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JumpRoACH: A Trajectory-Adjustable Integrated Jumping-Crawling Robot
Abstract
In this paper, we present a milli-scale integrated jumping-crawling robot that can adjust its launch trajectory and upright itself. This multi-modal robot shows an enhanced performance of overcoming obstacles compared to a robot with a single locomotion mode. To make this possible, the robot uses a newly developed jumping module with improved energy storing-capacity and a height-adjustable active clutch. The jumping module utilizes both linear springs and torsional springs to maximize the energy-storing capacity under the given limit of structural robustness. To adjust the quantity of stored energy and release the energy at any state, an active clutch mechanism based on a single DC motor is developed, which enables the robot to control both jump timing and height. Also, an active shell allows the robot to upright itself after landing and to continue jumping-crawling. The jumping module and the shell are integrated with the lightweight VelociRoACH crawler. To show the usability in real-world applications, the integrated jumping-crawling robot is tested on the cluttered terrain. In result, the robot reaches a target using jumping, crawling, and self-righting.
... This soft robot's control system consists of eight BMX100 SMA coils, and different values of the voltage will produce different deformations, making it possible for the soft robot to achieve corresponding heights [19]. The JumpRoACH robot generates variable energy in order to reach appropriate sites using a planetary gear system [20]. Taking into account energy utilization rates and the environmental adaptation of the robots, the second method will indubitably have more promising developments. ...
... In contrast, the driving gear rotates counterclockwise and drives the tie rod to rotate counterclockwise through a one-way bearing such that the transition gear is separated from the driven gear, the mechanism releases energy, and the robot performs its jumping movement. Although the clutch is similar to the clutch used by the JumpRoACH robot [20], there are underlying differences in its application principles. In the clutch we designed, the meshing and separation of the transition gear and the driven wheel are realized by the driving wheel driving the tie bar through a one-way bearing, while the clutch of the JumpRoACH robot is realized directly by the meshing force between the gears. ...
This paper presents the design and development of a miniature integrated jumping and running robot that can adjust its route trajectory and has passive self-righting. The jumping mechanism of the robot was developed by using a novel design strategy that combines hard-bodied animal (springtail) and soft-bodied animal (gall midge larvae) locomotion. It could reach a height of about 1.5 m under a load of 98.6 g and a height of about 1.2 m under a load of 156.8 g. To enhance the jumping flexibility of the robot, a clutch system with an adjustable height and launch time control was used such that the robot could freely switch to appropriate jumping heights. In addition, the robot has a shell with passive righting to protect the robot while landing and automatically self-righting it after landing, which makes the continuous jumping, running, and steering of the robot possible. The two-wheel mechanism integrated at the bottom of the housing mechanism provides the robot with horizontal running locomotion, which is combined with the vertical jumping locomotion to obtain different locomotion trajectories. This robot has the functions of obstacle surmounting, track adjustability, and load- and self-righting, which has strong practical application value.
... Rhomboidal jumpers have been developed various types of springs for power amplification, including the torsion springs [6], single extension spring [5], [7], multiple extension springs [8], [9] and combinations of torsion and extension springs [10]. However, a detailed comparison of these different arrangements is yet to be made. ...
... The second example uses a Hookean linear extension spring with ends connected to joints B and D (Fig. 2b); this layout has been used in several previous examples of jumping robots [5], [7], [8], [10]. The actuator force is ...
... [21] 115. 6 28 305 232 Yes 54.9 JumpRoACH [24] 42.6 11.5 275 0 Yes 41.1 Jump-flapper [23] 23 -86 -Yes 9.1 MSU jumper [12] 23.5 6 Catapult mechanisms are most frequently accepted by jumping robots, which allow them to slowly store energy in elastic elements with actuators, and then suddenly release the elastic energy via latch or catch mechanisms to trigger the push-off. The frogbot [15] uses a geared six-bar mechanism paralleled with a linear spring, and the elastic energy storage or release is achieved by a motor with one-way clutches. ...
... Strategies for energy storage and release using cables and clutches are used in Multimo-Bat [21,22] and Jump-flapper [23] . The JumpRoACH uses both torsional springs and linear springs to enhance its energy density, and the height-adjustable trigger is achieved by an active clutch [24] . The TAUB [25,26] has a pair of two-bar legs jointed by torsional springs. ...
Compared with the catapult mechanism widely employed by small jumping robots, recently proposed jumping strategies based on series-elastic actuators (SEA) without latch mechanisms perform better in terms of agility, structural robustness and maneuverability. However, in some practical applications, they have difficulty in effectively storing energy before the push-off. This paper presents a novel no-latch jumping strategy inspired by frogs, achieving highly effective energy storage. The jumping strategy combines an SEA with a parallel-elastic linkage, which allows one motor to rotate in one direction to store the elastic energy and automatically trigger its release. Combined with this strategy, a frog-inspired robotic leg mechanism is designed. The jumping process is analysed in detail and the kinematic and dynamic models are derived. Bars’ dimensions and springs’ parameters are determined by the optimization to maximize the energy-storing capacity. The simulation is performed to predict the jumping performance. A 100.7 g prototype is fabricated and jumps to a height of 1.3 m with slight aerial body rotation. The energy-storing capacity of the robot is 18.1 J/Kg.
... The performance is changed by changing the spring stiffness of their SMA springs by varying the input current; the Joule heating changes the material properties of the SMA spring, thereby changing the total energy stored. Jumpers such as the JumpROACH robot are able to change its stored elastic energy and thus its jump height, by using an active clutch mechanism [17,18]. Another novel jumping robot includes the magnetically actuated 3.1 mm jumper that consists of a latex spring attached to a 5-bar linkage mechanism driven by a pair of magnetically-actuated gears [19]. ...
Small jumping robots can use springs to maximize jump performance, but they are typically not able to control the height of each jump owing to design constraints. This study explores the use of the jumper’s latch, the component that mediates the release of energy stored in the spring, as a tool for controlling jumps. A reduced-order model that considers the dynamics of the actuator pulling the latch and the effect of spring force on the latch is presented. This model is then validated using high speed video and ground reaction force measurements from a 4 g jumper. Both the model and experimental results demonstrate that jump performance in small insect-inspired, resource-constrained robots can be tuned to a range of outputs using latch mediation, despite starting with a fixed spring potential energy. For a fixed set of input voltages to the latch actuator, the results also show that a jumper with a larger latch radius has greater tunability. However, this greater tunability comes with a trade-off in maximum performance. Finally, we define a new metric, ’Tunability Range,’ to capture the range of controllable jump behaviors that a jumper with a fixed spring compression can attain given a set of control inputs (i.e., latch actuation voltage) to choose from.
... Some robotic jumpers can right themselves once on the ground after an upside-down landing. To correct their posture, they use either motorized levelers deployed against the ground (Jung et al 2019) or the force due to gravity (Ma et al 2021). Robots with the ability to control pitch in mid-air have been successfully designed based on the inertial responses of the tail (Libby et al 2012, Haldane et al 2016 and the elongated tails of lizards and geckos during jumping and descending, respectively (Jusufi et al 2008, 2010, Siddall et al 2021a. ...
Recent observations of wingless animals, including jumping nematodes, springtails, insects, and wingless vertebrates like geckos, snakes, and salamanders, have shown that their adaptations and body morphing are essential for rapid self-righting and controlled landing. These skills can reduce the risk of physical damage during collision, minimize recoil during landing, and allow for a quick escape response to minimize predation risk. The size, mass distribution, and speed of an animal determine its self-righting method, with larger animals depending on the conservation of angular momentum and smaller animals primarily using aerodynamic forces. Many animals falling through the air, from nematodes to salamanders, adopt a skydiving posture while descending. Similarly, plant seeds such as dandelions and samaras are able to turn upright in mid-air using aerodynamic forces and produce high decelerations. These aerial capabilities allow for a wide dispersal range, low-impact collisions, and effective landing and settling. Recently, small robots that can right themselves for controlled landings have been designed based on principles of aerial maneuvering in animals. Further research into the effects of unsteady flows on self-righting and landing in small arthropods, particularly those exhibiting explosive catapulting, could reveal how morphological features, flow dynamics, and physical mechanisms contribute to effective mid-air control. More broadly, studying apterygote (wingless insects) landing could also provide insight into the origin of insect flight. These research efforts have the potential to lead to the bio-inspired design of aerial micro-vehicles, sports projectiles, parachutes, and impulsive robots that can land upright in unsteady flow conditions.
... Jumping locomotion overcomes the limitations imposed by their small size and is an effective locomotion method for travelling over discontinuous paths and obstacles. Several studies have attempted to increase jumping performance by amplifying the power output of the motor and have used elastomers to do so [1][2][3][4][5][6][7]. ...
Hopping locomotion has the potential to enable small-scale robots to maneuver lands quickly while overcoming obstacles bigger than themselves. To make this possible, in this paper, we propose a novel design of a high-power linear actuator for a small-scale hopper. The key design principle of the linear actuator is to use a power spring and an active clutch. The power spring provides a near constant torque along the wide range of output displacement. The active clutch controls the moving direction and operation timing of the linear actuator, which enables the hopper to take off at the right timing. As a result, the hopper has a size of 143 mm, a mass of 45.9 g, and hops up to 0.58 m.
... Although these robots have achieved high jumps, none have been able to adjust their jumping height or takeoff angle. JumpRoACH [6] and SNU Jumper [7] demonstrated adjustable jumping trajectories, but lacked precision. Salto-1P [8] is the smallest jumper capable of precisely controlling its jumping motion; the standard deviation (STD) of the jumping distance is approximately 1.6-5.6 cm. ...
... Next, we describe the essential performance metrics of jumping and benchmark the jumping height of JUMPA robots with various beam configurations against that of insects (1,3,4,(9)(10)(11)(35)(36)(37)(38)(39)(40)(41), and previous robots (15)(16)(17)(42)(43)(44)(45)(46)(47)(48)(49)(50). In Fig. 5C, we plot the raw jumping data, namely jump height versus size (maximum body length). ...
Millions of years of evolution have allowed animals to develop unusual locomotion capabilities. A striking example is the legless-jumping of click beetles and trap-jaw ants, which jump more than 10 times their body length. Their delicate musculoskeletal system amplifies their muscles' power. It is challenging to engineer insect-scale jumpers that use onboard actuators for both elastic energy storage and power amplification. Typical jumpers require a combination of at least two actuator mechanisms for elastic energy storage and jump triggering, leading to complex designs having many parts. Here, we report the new concept of dynamic buckling cascading, in which a single unidirectional actuation stroke drives an elastic beam through a sequence of energy-storing buckling modes automatically followed by spontaneous impulsive snapping at a critical triggering threshold. Integrating this cascade in a robot enables jumping with unidirectional muscles and power amplification (JUMPA). These JUMPA systems use a single lightweight mechanism for energy storage and release with a mass of 1.6 g and 2 cm length and jump up to 0.9 m, 40 times their body length. They jump repeatedly by reengaging the latch and using coiled artificial muscles to restore elastic energy. The robots reach their performance limits guided by theoretical analysis of snap-through and momentum exchange during ground collision. These jumpers reach the energy densities typical of the best macroscale jumping robots, while also matching the rapid escape times of jumping insects, thus demonstrating the path toward future applications including proximity sensing, inspection, and search and rescue.
... Although they achieved large jumping heights but none of them could adjust the jumping trajectory. JumpRoACH [8] and SNU Jumper [9] demonstrated adjustable jumping trajectory but still lack of precision. Salto-1P [10] could perform precise jumps. ...
p>The jumping trajectory control is important for the jumping robots to overcome different obstacles. However, the trajectory control of a micro jumping robot is not easy. No insect-scale jumping robots have demonstrated the precise trajectory following yet. We proposed a miniature origami omnidirectional jumping robot (Moobot) that achieved the feedback control of jumping trajectory. The jumping of the robot is based on a four-bar origami structure and the SMA actuators. Unlike the tethered micro robots that powered externally, we integrated a miniature control board with LiPo battery on the robot for remote control. The overall system measured 6 g in mass, 5.5 cm in length and 2cm in height. Two strain gauges and an IMU sensor were used on the robot for the feedback control of the jumping force and take-off angle, respectively. Meanwhile, a reliable jumping mechanism and a novel supporting leg were designed to improve the jumping stability and trajectory accuracy. The standard deviation of the jumping distances was less than 1.4 cm, which is greatly improved from all previous micro jumping robots. Furthermore, we integrated the yaw control and conducted the omnidirectional jumping experiments. The results revealed that Moobot could climb different platforms from all directions precisely.</p
... Although they achieved large jumping heights but none of them could adjust the jumping trajectory. JumpRoACH [8] and SNU Jumper [9] demonstrated adjustable jumping trajectory but still lack of precision. Salto-1P [10] could perform precise jumps. ...
p>The jumping trajectory control is important for the jumping robots to overcome different obstacles. However, the trajectory control of a micro jumping robot is not easy. No insect-scale jumping robots have demonstrated the precise trajectory following yet. We proposed a miniature origami omnidirectional jumping robot (Moobot) that achieved the feedback control of jumping trajectory. The jumping of the robot is based on a four-bar origami structure and the SMA actuators. Unlike the tethered micro robots that powered externally, we integrated a miniature control board with LiPo battery on the robot for remote control. The overall system measured 6 g in mass, 5.5 cm in length and 2cm in height. Two strain gauges and an IMU sensor were used on the robot for the feedback control of the jumping force and take-off angle, respectively. Meanwhile, a reliable jumping mechanism and a novel supporting leg were designed to improve the jumping stability and trajectory accuracy. The standard deviation of the jumping distances was less than 1.4 cm, which is greatly improved from all previous micro jumping robots. Furthermore, we integrated the yaw control and conducted the omnidirectional jumping experiments. The results revealed that Moobot could climb different platforms from all directions precisely.</p
... Although they achieved large jumping heights but none of them could adjust the jumping trajectory. JumpRoACH [8] and SNU Jumper [9] demonstrated adjustable jumping trajectory but still lack of precision. Salto-1P [10] could perform precise jumps. ...
p>The jumping trajectory control is important for the jumping robots to overcome different obstacles. However, the trajectory control of a micro jumping robot is not easy. No insect-scale jumping robots have demonstrated the precise trajectory following yet. We proposed a miniature origami omnidirectional jumping robot (Moobot) that achieved the feedback control of jumping trajectory. The jumping of the robot is based on a four-bar origami structure and the SMA actuators. Unlike the tethered micro robots that powered externally, we integrated a miniature control board with LiPo battery on the robot for remote control. The overall system measured 6 g in mass, 5.5 cm in length and 2cm in height. Two strain gauges and an IMU sensor were used on the robot for the feedback control of the jumping force and take-off angle, respectively. Meanwhile, a reliable jumping mechanism and a novel supporting leg were designed to improve the jumping stability and trajectory accuracy. The standard deviation of the jumping distances was less than 1.4 cm, which is greatly improved from all previous micro jumping robots. Furthermore, we integrated the yaw control and conducted the omnidirectional jumping experiments. The results revealed that Moobot could climb different platforms from all directions precisely.</p
... Jumping is a very effective way to overcome unfavorable ground conditions and obstacles of various sizes. Most jumping robots use elastic elements such as springs to store and release mechanical energy to enable the robot to jump and reach high heights [22], [23], [24], [25], [26]. Some robots can be actuated by combustion [27], the thermomechanical response of shape memory alloys (SMA) [28], single-domain liquid crystal elastomers (LCE) [29], etc. ...
Insects and animals in nature generally have various modes of locomotion to adapt to complex environments, such as crawling, running, flying, and jumping. Achieving multi-locomotion in a centimeter-scale robot requires complex structures and mechanisms that are normally difficult to design and fabricate. In this article, we propose a centimeter-scale robot powered by electrohydrodynamic propulsion capable of rolling, hopping, and taking off. The robot's mass, body length, and height are 203 mg, 6.5 cm, and 4.1 cm, respectively. The robot has a simple mechanical structure, consisting of electrohydrodynamic thrusters, wheels, and supporting beams. By only controlling the magnitude of the thrust, the proposed robot can roll, hop, and take off. The experimental results show that this robot's rolling speed reaches 72.1 cm/s (11.1 body length/s). The takeoff of the robot along a vertical guide and the hopping performance over various obstacles are also demonstrated. This study extends the potential for applying electrohydrodynamic propulsion to centimeter-scale robots.
... TAUB achieved the jumping orientation control by a propeller-shaped tail mechanism [2]. JumpRoACH used a cellular gear mechanism for jumping height control [3]. The Salto-1P was successful progress toward a fully controllable jumping robot, which achieved the adjustment of air attitude, take-off angle, and jumping height by the series-elastic power modulation and an inertia tail [4] [5] [6]. ...
... In addition, researchers at the University of California, Berkeley, have conducted a series of interesting explorations based on these robots, such as tumbling, jumping, etc., which has further broadened the scope of their application. In addition, researchers at the University of California, Berkeley, have also developed many outstanding RoACH-derived micro-robots [53][54][55][56][57], and these micro-robots are therefore more likely to be used in real environments. ...
This article introduces and explores the current frontier four-legged (quadruped) and six-legged (hexapod) crawling micro-robots. The performances of various crawling micro-robots are compared, and their driving modes are analyzed. Moreover, the research status of crawling micro-robots is summarized, and the future application prospects and development directions of these robots are put forward.
... Recently, many jumping robots have been developed, including JumpRoach, 52 Tribot, 53 Surveillance Robot, 54 MSU tailbot, 55 Salto-1p, 56 and Flea. 57 With advancements in manufacturing technology, microactuators, and biomimetic technology, existing miniature jumping robots can achieve longer jumping distances and higher jumping heights while remaining as small and light as insects. ...
Jumping locomotion is critical for microrobots to overcome obstacles. Among the microjumping robots, the development of an omnidirectional jumping mechanism is challenging. To avoid the complicated microfabrication process, we present an insect-computer hybrid robot by controlling the locomotions of an Oriental Migratory Locust (Locusta migratoria manilensis, Meyen 1835). The insect-computer hybrid robot achieves repetitive omnidirectional jumps of ∼100 mm high. A series of experiments on jumping control, turning control, and collaborative directional jumping control are carried out. We also demonstrate the implementation of a wireless stimulator backpack that provides remote locomotion control, which transforms the insect into a hybrid robot. Moreover, a feedback jump control system is subsequently presented. The results indicate that the hybrid robot could easily achieve an omnidirectional jump and maintain body righting after landing. This robot is well-suited for applications that require locomotion on uneven terrains, such as environmental surveillance and search and rescue.
... Lussier developed an amphibious robot that combines crawling and flying, which can crawl, take off, and land on smooth/rough surfaces [10,11]. Robots that combine crawling and jumping modes can expand traversability in unstructured environments [12], and there are robots that mimic the locomotion strategies of vampire bats (MultiMo-Bat) and locusts (Jump-flapper), with capabilities of jumping and flying [13,14]. In the bimodal robot "LEONARDO", the combination of bipedal movement and flight movement not only improves the robot's movement ability, but also results in flexible and stable motion [15]. ...
The better application of crawl robots depends on their ability to adapt to unstructured environments with significant variations in their structural shape and size. This paper presents the design and analysis of a novel robot with different locomotion configurations to move through varying environments. The leg of the robot, inspired by insects, was designed as a multi-link structure, including the Hoekens linkage and multiple parallel four-link mechanisms. The end trajectory was a symmetrical closed curve composed of an approximate straight line and a shell curve with a downward opening. The special trajectory allowed the robot to share drives and components to achieve structural deformation and locomotion. The structural characteristics of the crawl robot on the inner and outer arcs were obtained based on the working space. The constraint relationship between the structure size, the radius of the arc, and the coefficient of static friction with which the robot could crawl on the arc were established. The feasible support posture and support position of the robot under different arc radii were obtained. The simulation tested the locomotion of the robot on the plane, arc, and restricted space. The robot can be used for detection, search, and rescue missions in unstructured environments.
... Jumping Sumo [6] and Jumping Night Drone [7] use an eccentric cam. JumpRoARC [8] uses a pantograph mechanism and an active clutch. Scout robot [9] uses an elastic plate. ...
Impulse force is effective for purposes such as system analysis, mobile robots, and haptic devices. However, the most popular DC motor actuator is not suitable for generating an impulse force. Thus, the lack of a compact impulse force generator has become a problem. We propose a snap motor that is a compact and rapid impulse force generator. In this paper, we propose a slider mechanism for the arched snap motor to increase the durability of the frame. This paper shows a reasonable explanation the function of the slider mechanism on an arched snap motor with simulation. Then, experiments showed that the energy conversion efficiency of the input electric energy to the buckling energy is about 60%. This paper provides a design method for a simple and compact impulse force generator.
... For a jumping robot, the ability of the robot to self-righting after landing is important in order to achieve multiple jumps. There is a diversity of self-righting methods in jumping robots, such as passive self-righting [8] Rigid Links Flexible Hinge SMA Spring Fig. 2: Robot's mechanical structure and active self-righting [9], [10]. For insect-scale jumping robots, most researchers focus on improving the jumping maneuverability and multi-modal locomotion. ...
We present the first demonstration of a battery-free untethered wirelessly powered sub-gram jumping robot on an insect-scale. In order to operate the insect-sized robot autonomously, the limitation in battery use emphasizes the need for a wireless power transmission system as an onboard power solution. We designed a wireless power transmission system based on inductive coupling to power the Shape Memory Alloy (SMA), which serves as an elastic energy storage element and actuator for the jumping robot. The assembled mechanical structures, onboard power and electronics yield a ~2 mm
(high) x 24 mm (long) x 12 mm (wide) robot with a weight of ~216 mg. The experiments show that our jumping robot wirelessly lift-off up to 5.75 times its body length and repeats the jump around 7 times per minute. To date, out of the several untethered sub-gram insect-scale jumping robots with onboard power, this is the first wirelessly powered robot with the highest jumping performance. The novelty in this work, which addresses the engineering challenges in insect-scale jumping robots, is an untethered wirelessly powered design that achieves dynamic jumping maneuvers, and has self-righting ability.
... Apart from locomotion on mobile platforms, different humanoid-based locomotion strategies have also been developed [4][5][6][7][8][9][10]. Researchers have also focused on the development of other legged robots like the quadruped robots [11][12][13][14], the transleg robots [15], etc. Different other robots have been developed after being inspired by the unique motion behavior of the animals, like the "lizard-Inspired robot" [16,17], the "dolphin-like robot" [18], the "snake-robot" [19][20][21], the bioinspired "jump-roach" [22] robot, and the legged hopping robot [23]. Apart from the mammal-like and the mobile robot-like motion, skate-like motion has been developed for these robots [24][25][26][27]. ...
The continuous contact-based skating technique utilises the sideways movement of the two skates while changing the orientation of the two skates simultaneously. The skates remain in contact with the surface. A mathematical model mimicking a continuous skating technique is developed to analyse the kinematic behaviour of the platform. Kinematic and dynamic equations of motion are derived for the impending non-holonomic constraints. Heuristic-based motion primitives are defined to steer the robotic platform. For the lateral movement of the platform, a creeping based motion primitive is proposed. A prototype of the robotic platform is developed with three actuated degrees of freedom – orientation of two skates and distance between them. A multibody model of the platform is also developed in MATLAB. Analytical expressions are verified to be useful using the simulation and experimental results. The robotic platform follows the desired motion profiles. However, the initial deviation has been observed in both the simulations and experiments due to the slipping of the roller skate at the contact point with the surface. The platform can be effectively used in a structured environment autonomously.
... This robot toy, actually a two-wheeled inverted pendulum, can move fast on a flat ground, and jump up to the height of 0.8 m. The collaboration research by Cho and Fearing invented a mobile and jumping robot, JumpRoACH, which can adjust the jumping height [24]. This light and small robot utilizes an elastic pantograph combined with an active clutch for a quick energy release, and has a capability of 0.72 m jump with running. ...
Pulsatile flow is widespread in nature, but replicating such impulsive periodic pumping routines with traditional rotary actuators is complex and energetically inefficient. We demonstrate the feasibility of an actuator capable of generating impulsive flow displacement by exploiting the bistable equilibrium of a simple mechanism. These kind of mechanisms, commonly known as snap-through mechanisms, offer the benefit of sudden release of elastic energy at the interface between two stable structural configurations. This property has been employed in certain actuators to drive abrupt motions of mechanical systems. Here, we use this principle to drive an inflation/deflation routine of a fluid-filled cavity, thus generating a peaked, pulsatile flow, comparable to that encountered in biological systems. Assessment of the various stages of actuation of this system shows that a sharp drop in the energy occurs from elastic to hydraulic work, highlighting the need for improved design elements involved in this stage of the actuation.
This research provides a thorough investigation of the self-balancing capabilities of long-range jumping robots. The study focuses on the concepts underlying jumping robots' self-balancing mechanisms and their capacity to retain stability during lengthy jumps. The existing literature on self-balancing robots is reviewed, with an emphasis on the various ways utilized to accomplish self-balancing. The research looks at the dynamics of the jumping robot during takeoff , flight, and landing, as well as the efficiency of the self-balancing system in maintaining stability. The findings show that the self-balancing mechanism greatly enhances the stability and accuracy of long-distance leaps and that it can be adjusted by modifying different design factors such as mass distribution and spring stiffness. The study's observations can be helpful for future generations of jumping robot designers and developers for tasks including search and rescue, surveillance, and exploration.
Bionic robotics and actuators have made dramatic advancements in structural design, material preparation, and application owing to the richness of nature and innovative material design. Appropriate and ingenious sources of bio-inspiration can stimulate a large number of different bionic systems. After millennia of survival and evolutionary exploration, the mere existence of life confirms that nature is constantly moving in an evolutionary direction of optimization and improvement. To this end, bio-inspired robots and actuators can be constructed for the completion of a variety of artificial design instructions and requirements. In this article, the advances in bio-inspired materials for robotics and actuators with the sources of bio-inspiration are reviewed. The specific sources of inspiration in bionic systems and corresponding bio-inspired applications are summarized first. Then the basic functions of materials in bio-inspired robots and actuators is discussed. Moreover, a principle of matching biomaterials is creatively suggested. Furthermore, the implementation of biological information extraction is discussed, and the preparation methods of bionic materials are reclassified. Finally, the challenges and potential opportunities involved in finding sources of bio-inspiration and materials for robotics and actuators in the future is discussed.
Tensegrity structures made from rigid rods and elastic cables have unique characteristics, such as being lightweight, easy to fabricate, and high load-carrying to weight capacity. In this article, we leverage tensegrity structures as wheels for a mobile robot that can actively change its shape by expanding or collapsing the wheels. Besides the shape-changing capability, using tensegrity as wheels offers several advantages over traditional wheels of similar sizes, such as a shock-absorbing capability without added mass since tensegrity wheels are both lightweight and highly compliant. We show that a robot with two icosahedron tensegrity wheels can reduce its width from 400 to 180 mm, and simultaneously, increase its height from 75 to 95 mm by changing the expanded tensegrity wheels to collapsed disk-like ones. The tensegrity wheels enable the robot to overcome steps with heights up to 110 and 150 mm with the expanded and collapsed configuration, respectively. We establish design guidelines for robots with tensegrity wheels by analyzing the maximum step height that can be overcome by the robot and the force required to collapse the wheel. The robot can also jump onto obstacles up to 300-mm high with a bistable mechanism that can gradually store but quickly release energy. We demonstrate the robot's locomotion capability in indoor and outdoor environments, including various natural terrains, like sand, grass, rocks, ice, and snow. Our results suggest that using tensegrity structures as wheels for mobile robots can enhance their capability to overcome obstacles, traverse challenging terrains, and survive falls from heights. When combined with other locomotion modes (e.g., jumping), such shape-changing robots can have broad applications for search-and-rescue after disasters or surveillance and monitoring in unstructured environments.
Kangaroo rats are well known as representative hoppers in small-scale animals. Especially kangaroo rats show rapid movement when a predator approaches. If this amazing motion can be applied to small-scale robots, they will be able to traverse lands at high speed while overcoming size limitations. To take advantage of hopping locomotion, in this paper, we present a lightweight and small-scale clutch-based hopping robot called Dipo. To make this possible, a compact power amplifying actuation system has been developed using a power spring and an active clutch. The power spring is possible to take out and use the accumulated energy little by little whenever the robot starts to hop. Moreover, the power spring needs low torque to charge the elastic energy, and a only tiny space is required to install. The active clutch controls the motion of hopping legs by adjusting the timing of energy release and storage. Thanks to these design strategies, the robot weighs 45.07g, has the height of 5 cm in the stance phase, and achieves the maximum hopping height of 54.9 cm.
Jumping mechanisms constitute an important means of resolution in applications such as crossing uneven terrain and space exploration. However, the traditional design mainly uses engineering design thinking, but seldom studies the structural characteristics of organisms themselves and lacks biomimetic research basis, which leads to the difference between jumping mechanism and biological structure and its jumping ability. On the other hand, it lacks in-depth study on biological jumping mechanism from the view of engineering. Weevil has excellent jumping performance, and its key jumper structure is specially designed by biologist. To investigate the motion mechanism and working mechanism of the jumping mechanisms, this paper takes the weevil as the bionic object, and designs a weevil-inspired jumping mechanism. A miniature prototype is designed to reproduce weevil’s jumping mechanism with its working principle and anatomical structure to verify how weevil’s jumping mechanisms work, and turns out to perform well at jumping height. This paper is presented the anatomical structure and working principle of the weevil jumping mechanism, followed by explanation and analysis of its kinematics and dynamics, then performing virtual prototype simulations to compare different design schemes, with results guiding the parameter optimization and subjecting a prototype machine into a height test. In comparisons among existing jumping mechanisms whose jumping method is bio-inspired, the present design, which weighs 44.7 g and can jump to a maximum height of 2 m. The present research establishes a biologically inspired working principle and provides a new practical archetype in biologically inspired studies.
Small-scale jumping robots are promising for rugged terrain locomotion due to their strong ability to overcome obstacles. Appendages are widely adopted by them to improve maneuverability and thus better adapt to real-world applications. However, existing appendages of small-scale jumping robots have limited operational modes or control degrees of freedom (DOFs), constraining their functionality. Here, we present a maneuvering mechanism with two-DOF inertial appendages to improve the maneuverability of jumping robots. It allows the robot to function diversely in different phases by changing the operation behavior. The terrestrial maneuverability is endowed by advanced appendage–ground interactions. By smoothly driving the appendages to control two-DOF body attitude before triggering the jump, the robot allows the omnidirectional jumping trajectory modulation. By controlling the rhythmic disengagement and contact between the appendages and the flat substrate, the crawling locomotion mode is achieved. In the aerial maneuver, the robot redirects its angular momentum to stabilize its two-DOF body attitude through rapid appendage manipulation. Such multifunctional appendages provide a versatile solution for jumping robots to improve maneuverability.
The toe joints play an important role in human walking and running movement patterns. In this paper, we propose a design method for metamorphic foot structures based on spring-loaded linkages to realize metatarsal-toe switching by using the self-recovery and self-stabilization properties of the spring-loaded linkages. We constrain the degrees of freedom (DOFs) of the foot mechanism by using the singular position characteristic of the four-bar mechanism to compensate for the lack of rigidity when the foot mechanism is in the toe line state. In addition, the structural parameters are calculated based on the static analysis method, and the validity of the design method is verified by simulation using Adams software. Finally, the compliance of the metatarsal state and the stability of the toe line state are demonstrated by physical prototyping and experiments. The results show that the novel metamorphic foot mechanism provides a uniform solution to cope with both walking and running movement modes.
Legged robots can negotiate unstructured environments and have applications in education, environmental inspection, space exploration, and cargo transportation. As a powerful form of legged robots, jumping robots have attractive features due to their high efficiency, mobility, traverse obstacles, and low cost of transport. Although spring is the core component of the energy system, little related work explores the value selection of spring stiffness and the effect of different spring placements for jumping robots. In this article, we present a systematic method to select the stiffness of spring based on static analysis, jumping linkage configuration and multi-objective optimization for jumping robots. Also, to predict the motion behavior of jumping robots, we provide a comprehensive dynamic model of the robotic jumping in different phases according to the Lagrange method and the principle of virtual work, which considers the motion constraints and configuration constraints simultaneously. The proposed method and dynamic model can validate by designing a spring-linkage-based jumping robot as a showcase. The experimental results show performance improvements in jumping height in terms of both different springs’ stiffness and arrangement, which is possible to appraise a maximal enhancement of 57.88%.
This work introduces the reconfigurable, foldable, legged, and miniature robot (REMIRO), a palm-size modular robot with compliant c-shaped legs. The robot’s body modules are made by folding acetate sheets. The legs connected to these modules are made of Polydimethylsiloxane (PDMS) using molding. The backbone modules are made of Thermoplastic polyurethane (TPU) using 3D printing. In this study, we propose a path tracking algorithm for our robot that enables our modules to move from a random initial location to the pose required to lock with another module. We also design and manufacture backbones with embedded permanent magnets to allow connection between modules. We also present a kinematic model of our robot utilizing c-shaped leg kinematics, predicting the forward differential kinematics of the robot, which is then used to test the path tracking algorithm. Our experiments show that the proposed path tracking algorithm moves our robot to the desired location with an average positioning error of 5mm and an average orientation error of 22°, which are small enough to permit docking between modules.
A small-scale jumping–crawling robot expands the accessible region of a robot by selectively performing suitable locomotion type. However, the parallel elastic actuation for jumping, which amplifies a lightweight actuator's limited power, couples the motion between the energy storing process and the crouching of the jumping linkage. This coupling hinders the quick transition of the locomotion from jumping to crawling and limits the jumping height control. Furthermore, these two defects degrade the agility and the energy-efficiency of the robot. In this article, we present a jumping–crawling robot with enhanced agility and energy-efficiency by decoupling the energy storage and crouching of the jumping linkage. The decoupling is achieved by implementing a passive clutch that properly switches the connection between the energy storage component and the jumping linkage. As a result, the proposed jumping–crawling robot can promptly change the locomotion type, and can adjust the jumping height from 0.1 to 0.8 m. These features reduce the time and energy consumption of the jumping–crawling robot during the demonstration of multimodal locomotion up to 40 and 30% respectively, compared to the robot without the proposed decoupling approach.
Animal locomotion results from a combination of power modulation and cyclic appendage trajectories, but combining these two properties in small-sized robots is difficult. Here, we introduce and characterize a new elastic actuation system based on an inverted cam that is capable of generating cyclic locomotion with controlled elastic energy charge and release for small-sized robots. We designed a leg linkage and attached to the inverted cam to develop a single legged hopping platform with one actuated degree of freedom. The hopping platform was able to continuously hop forward at 1.82 Hz. The average horizontal hopping distance was 18.7 cm, and the average forward speed was 0.34 m/s. This speed was corresponding to a Froude number of 0.14. The energy consumed for one hop was 2.09 J, and the corresponding energetic cost of transport was 6.43. The combination of inverted cam and cyclic trajectory generation has the potential to be used in other robotic applications, such as flapping wings in the air and tail fin waving in water.
This study investigates the effects of control uncertainties and random feet failures on the locomotion of the multi-legged miniature robots. The locomotion analyses results are verified with our modular multi-legged miniature robot with a soft/hybrid body named SMoLBot. A single SMoLBot module is 44.5 mm wide, 16.75 mm long, and 15 mm high with two individually actuated and controlled DC motors. This individual actuation makes it feasible to run with any imaginable gait, making SMoLBot a nice candidate for gait study analyses. The presented locomotion study shows that the effects of control uncertainties and feet failures are highly dependent on the total number of legs and the type of backbone attached to the robot, e.g., increasing the total number of legs or utilizing a rigid backbone on the robot helps the robot to walk faster compared to similar robots with soft backbones or the ones with fewer modules. This study presents a guide to the researchers on the effects of feet failures and control uncertainties on the locomotion of soft/hybrid multi-legged miniature robots.
Twisted and coiled polymer (TCP) actuators are becoming increasingly prevalent in soft robotic fields due to their powerful and hysteresis-free stroke, large specific work density, and ease of fabrication. This paper presents a soft crawling robot with spike-inspired robot feet which can deform and crawl like an inchworm. The robot mainly consists of two leaf springs, connection part, robot feet, and two TCP actuators. A system level model of a soft crawling robot is presented for flexible and effective locomotion. Such a model can offer high-efficiency design and flexible locomotion of the crawling robot. Results show that the soft crawling robot can move at a speed of 0.275 mm/s when TCP is powered at 24 V.
The lateral fall of a quadruped robot is difficult to avoid. However, there are few studies on the fall recovery of quadruped robots, especially that with large size and weight. One of the important reasons originates from the driving capability of robot joints. This paper analyzes the fall recovery behavior of several animals in nature, and designs a bionic shell structure. Then the working mechanism and critical conditions of the shell have been studied in detail. The shell that with the ability of regulating the energy changes of the robot when rolling, can make the quadruped robot withstand large impacts and avoid tipping. Based on the compliant movement generated by the arc-shaped contour of the bionic shell, the demand for the explosive joint driving force can be greatly reduced. These inherent advantages of the mechanism of the shell make it suitable for the lateral fall recovery of a large quadruped robot. The effectiveness of the mechanism is verified by simulation. Moreover, the performance of the bionic shell is discussed, for different factors including impacts, terrains and structures.
The jumping motion is adapted by Earth’s creatures to achieve rapid maneuverability and energy-efficient hurdling over uneven terrains or large obstacles. Herein, the continuous photomechanical jumping of polymer monoliths with on-demand height and angle programmability is reported. Upon exposure to actinic light, self-assembled spring-like molecular geometry of azobenzene-functionalized liquid crystalline polymers provide on-demand jumping via snap-through of non-isometric structures. The finite element method simulation quantitatively describes stress–strain responsivity of the experimental jumping. Remarkably, the maximum jumping height reaches 15.5 body length (BL) with the maximum instantaneous velocity of 880 BL s⁻¹. We demonstrate programmable jumping height and angle by varying macroscopic geometry and light intensity profile. Finally, four continuous and directional jumping sequences are demonstrated within 5 s to overcome an obstacle.
Chameleon tongue-like manipulators have the potential to be quite useful for mobile systems to overcome access issues by allowing them to reach distant targets in an instant. For example, a quadrotor with this manipulator will be able to snatch distant targets instead of hovering and picking up. In this letter, we present a chameleon-inspired shooting and rapidly retracting manipulator, which is lightweight, compact, and ultimately suitable for mobile systems. To make this possible, two design strategies are proposed: to use a wind-up spring as an energy source and to employ an active clutch to selectively distribute the energy. The wind-up spring enables the device to keep supplying the stored energy for a long time, compared to normal torsion springs. The active clutch controls the direction and the timing of the energy supply, which allows to deploy and retract the end-effector. Thanks to these design strategies, the device achieves snatching manipulation while maintaining compact and lightweight. In result, the Snatcher has a size of 120x85x85mm, weighs 117.48g, and brings a 30g mass located at 0.8m away within 600ms.
The CaseCrawler is a lightweight and low-profile movable platform with a high payload capacity; it is capable of crawling around carrying a smartphone. The body of the robot resembles a phone case but it has crawling legs stored in its back. It is designed with a deployable, in-plane transmission that is capable of crawling locomotion. The CaseCrawler's leg structure has a knee joint that can passively bend only in one direction; this allows it to sustain a load in the other direction. This anisotropic leg allows a crank slider to be used as the main transmission for generating the crawling motion; the crank slider generates a motion only within a 2D plane. The crank slider deploys the leg when the slider is pushed and retracts it when pulled; this enables a low-profile case that can fully retract the legs flat. Furthermore, by being restricted to swinging within a plane, the hip joint is highly resistant to off-axis deformation, this results in a high payload capacity. As a result, the CaseCrawler has a body thickness of 16mm (the transmission without the gearbox is only 1.5mm) and a total weight of 22.7g; however, it can carry a load of over 300g, which is 13 times its own weight. To show the feasibility of the robot for use in real-world applications, in this study, the CaseCrawler was employed as a movable platform that carries a 190g mass, including a smartphone and its cover. This robot can crawl around with the smartphone to enable the phone to charge itself on a wireless charging station. In the future, if appropriate sensing and control functions are implemented, the robot will be able to collect data or return to the owner when needed.
Pipe inspection is of great importance from both safety and cost perspectives. Despite extensive research, in-pipe robots with multi-locomotion capability have not been fully explored. Here, we develop a multi-locomotion soft robot, with a compact yet robust structure, that can hop for speed and crawl for maneuverability in horizontal and vertical pipes for pipe inspection. The robot consists of two motors, cables, and several longitudinally arranged elastic ribbons. These ribbons, with strategically designed profile, are 3D-printed and can be buckled into different three-dimensional shapes by pulling cables, thereby achieving hopping and crawling (forward and backward) by issuing different actuation sequences and parameters of the two motors. We studied the effect of ribbon design and pulling/releasing duration on the hopping and crawling performance. Our findings may shed light on the development of in-pipe robots with new functionality and applications.
Applying concepts and methods of bionics to endow autonomous robots with elegant and agile mobility just like natural living beings is gradually becoming a hot research topic in intelligent robot field. Compared with walking, crawling, rolling and other motion modes, jumping performs considerable advantages that can leap across obstacles and move to different heights in agility and flexibility. In this paper, we specifically review the developments of biologically inspired jumping robots in the past decades, and give comprehensive analysis on some key technologies for implementing a practical jumping robot effectively. First, the jumping mechanism of frog (amphibian, quadruped), locust (arthropod, hexapod), kangaroo (mammality, bipedalism) as examples of typical animals good at jumping is introduced and analyzed, from which it is concluded that power sources, limbs coordination and control are key elements for excellent jumping performances, which should be synthetically improved by combination with structure design and model establishment. Then, spring loaded inverted pendulum (SLIP), bio-inspired open-chain and closed-chain multi-linkage as representative jumping mechanical structures, their characteristics are explored accompanied with dynamic analysis. After a detailed analysis to actuators and energy storage devices and a comprehensive summarization to functional and soft materials commonly applied in jumping robots, different control methods and strategies adopted to achieve better jumping performance are reviewed and analyzed, from self-righting, driving control to path planning. Especially, how to analyze the stability of a jumping control system and how to stabilize it are explained theoretically by taking a vertical monopedal jumping robot as an example and via limit cycle analysis. Finally, some feasible and potential future developments in bio-inspired jumping robots are also presented after detailed discussions on current status and existing deficiencies.
Terrestrial animals and robots are susceptible to flipping-over during rapid locomotion in complex terrains. However, small robots are less capable of self-righting from an upside-down orientation compared to small animals like insects. Inspired by the winged discoid cockroach, we designed a new robot that opens its wings to self-right by pushing against the ground. We used this robot to systematically test how self-righting performance depends on wing opening magnitude, speed, and asymmetry, and modeled how kinematic and energetic requirements depend on wing shape and body/wing mass distribution. We discovered that the robot self-rights dynamically using kinetic energy to overcome potential energy barriers, that larger and faster symmetric wing opening increases self-righting performance, and that opening wings asymmetrically increases righting probability when wing opening is small. Our results suggested that the discoid cockroach’s winged self-righting is a dynamic maneuver. While the thin, lightweight wings of the discoid cockroach and our robot are energetically sub-optimal for self-righting compared to tall, heavy ones, their ability to open wings saves them substantial energy compared to if they had static shells. Analogous to biological exaptations, our study provided a proof-of-concept for terrestrial robots to use existing morphology in novel ways to overcome new locomotor challenges.
Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes the ability to extend the distance travelled and reduce the potentially damaging impact forces upon landing. This publication evaluates the performance of jump-gliding locomotion and provides models for the analysis of the relevant dynamics of flight. It also defines a jump-gliding envelope that encompasses the range that can be achieved with jump-gliding robots and that can be used to evaluate the performance and improvement potential of jump-gliding robots. We present first a planar dynamic model and then a simplified closed form model, which allow for quantification of the distance travelled and the impact energy on landing. In order to validate the prediction of these models, we validate the model with experiments using a novel jump-gliding robot, named the ‘EPFL jump-glider’. It has a mass of 16.5 g and is able to perform jumps from elevated positions, perform steered gliding flight, land safely and traverse on the ground by repetitive jumping. The experiments indicate that the developed jump-gliding model fits very well with the measured flight data using the EPFL jump-glider, confirming the benefits of jump-gliding locomotion to mobile robotics. The jump-glide envelope considerations indicate that the EPFL jump-glider, when traversing from a 2 m height, reaches 74.3% of optimal jump-gliding distance compared to pure jumping without a gliding phase which only reaches 33.4% of the optimal jump-gliding distance. Methods of further improving flight performance based on the models and inspiration from biological systems are presented providing mechanical design pathways to future jump-gliding robot designs.
Combined jumping and gliding locomotion, or 'jumpgliding', can be an efficient way for small robots or animals to travel over cluttered terrain. This paper presents functional requirements and models for a simple jumpglider which formalize the benefits and limitations of using aerodynamic surfaces to augment jumping ability. Analysis of the model gives insight into design choices and control strategies for higher performance and to accommodate special conditions such as a slippery launching surface. The model informs the design of a robotic platform that can perform repeated jumps using a carbon fiber spring and a pivoting wing. Experiments with two different versions of the platform agree with predictions from the model and demonstrate a significantly greater range, and lower cost-of-transport, than a comparable ballistic jumper.
A shape memory alloy (SMA) coil spring actuator is fabricated by annealing an SMA wire wound on a rod. Four design parameters are required for the winding: the wire diameter, the rod diameter, the pitch angle and the number of active coils. These parameters determine the force and stroke produced by the actuator. In this paper, we present an engineering design framework to select these parameters on the basis of the desired force and stoke. The behavior of the SMA coil spring actuator is described in detail to provide information about the inner workings of the actuator and to aid in selecting the design parameters. A new static two-state model, which represents a force–deflection relation of the actuator at the fully martensitic state (M100%) and fully austenitic state (A100%), is derived for use in the design. Two nonlinear effects are considered in the model: the nonlinear detwinning effect of the SMA and the nonlinear geometric effect of the coil spring for large deformations. The design process is organized into six steps and is presented with a flowchart and design equations. By following this systematic approach, an SMA coil spring actuator can be designed for various applications. Experimental results verified the static two-state model for the SMA coil spring actuator and a case study showed that an actuator designed using this framework met the design requirements. The proposed design framework was developed to assist application engineers such as robotics researchers in designing SMA coil spring actuators without the need for full thermomechanical models.
It has come to the attention of the authors that they omitted an author from the author list of the above article. The excluded author, Dr Richard Bomphrey (Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK, e-mail: richard.bomphrey@zoo.ox.ac.uk), made an important and early contribution to the work reported in the paper. The authors apologize for this oversight and gratefully acknowledge Dr Bomphrey's contribution to this work.
This paper describes the latest additions to the Mini-Whegs™ series of small robots. These new robots are fully enclosed, measure 9 to 10 cm long, and range in weight from 90 g to 190 g. Mini-Whegs™ 7 weighs less than 90 g, but can run at over three body-lengths per second and surmount 3.8 cm high obstacles. The most recent iteration, Mini-Whegs™ 9J, incorporates fully independent running and jumping modes of locomotion. The controllable jumping mechanism allows it to leap as high as 18 cm.
This paper describes the design of a fast long- jumping robot conceived to move in unstructured environments through simple feed-forward control laws. Despite the apparent similarities with hopping, jumping dynamics is peculiar and involve non-trivial issues on actuation powering, energy saving and stability. The "Grillo" robot described here is a quadruped, 50-mm robot that weights about 15 grams and is suited for a long-jumping gait. Inspired by frog locomotion, a tiny motor load the springs connected to the hind limbs. At take-off, an escapement mechanism releases the loaded springs. This provides a peak power output that can exceed several times the maximum motor power. In this way, the actuation and energy systems can be significantly reduced in weight and size. On the other hand, passive dynamics is exploited by compliant forelegs, that let to partially recover the impact energy in their elastic recoil. Equipped with a 0.2W DC motor, the robot is dimensioned to achieve a forward speed of 1.5 m/s, which corresponds to about 30 body length per second. I. INTRODUCTION
This paper introduces jumping robots as a means to traverse rough terrain; such terrain can pose problems for traditional wheeled, tracked and legged designs. The diversity of jumping mechanisms found in nature is explored to support the theory that jumping is a desirable ability for a robot locomotion system to incorporate, and then the size-related constraints are determined from first principles. A series of existing jumping robots are presented and their performance summarized. The authors present two new biologically inspired jumping robots, Jollbot and Glumper, both of which incorporate additional locomotion techniques of rolling and gliding respectively. Jollbot consists of metal hoop springs forming a 300 mm diameter sphere, and when jumping it raises its centre of gravity by 0.22 m and clears a height of 0.18 m. Glumper is of octahedral shape, with four 'legs' that each comprise two 500 mm lengths of CFRP tube articulating around torsion spring 'knees'. It is able to raise its centre of gravity by 1.60 m and clears a height of 1.17 m. The jumping performance of the jumping robot designs presented is discussed and compared against some specialized jumping animals. Specific power output is thought to be the performance-limiting factor for a jumping robot, which requires the maximization of the amount of energy that can be stored together with a minimization of mass. It is demonstrated that this can be achieved through optimization and careful materials selection.
Bio-inspired robotics is a promising design strategy for mobile robots. Jumping is an energy efficient locomotion gait for traversing difficult terrain. Inspired by the jumping and flying behavior of the desert locust, we have recently developed a miniature jumping robot that can jump over 3.5 m high. However, much like the non-adult locust, it rotates while in the air and lands uncontrollably. Inspired by the winged adult locust, we have added spreading wings and a tail to the jumper. After the robot leaps, at the apex of the trajectory, the wings unfold and it glides to the ground. The advantages of this maneuver are the stabilization of the robot when airborne, the reduction of velocity at landing, the control of the landing angle and the potential to change the robot's orientation and control its flight trajectory. The new upgraded robot is capable of jumping to a still impressive height of 1.7 m eliminating airborne rotation and reducing landing velocity. Here, we analyze the dynamic and aerodynamic models of the robot, discuss the robot's design, and validate its ability to perform a jump-glide in a stable trajectory, land safely and change its orientation while in the air.
This paper presents a vertically jumping robot based on the inertial actuation concept. Recent research studies in our System Laboratory proved that a wide range of inertially actuated locomotion systems can be generated. This can be achieved by using a family tree approach starting from a very simple system and progressively evolving it to more complex ones. We discovered that inertial actuation was an efficient method to regulate the motion of these robots. The hopper is the most basic member of this tree and efficient control of its motion using inertial actuation is essential to the design of every element in the family.
Several arboreal mammals have the ability to rapidly and repeatedly jump vertical distances of 2 m, starting from rest. We characterize this performance by a metric we call vertical jumping agility. Through basic kinetic relations, we show that this agility metric is fundamentally constrained by available actuator power. Although rapid high jumping is an important performance characteristic, the ability to control forces during stance also appears critical for sophisticated behaviors. The animal with the highest vertical jumping agility, the galago (Galago senegalensis), is known to use a power-modulating strategy to obtain higher peak power than that of muscle alone. Few previous robots have used series-elastic power modulation (achieved by combining series-elastic actuation with variable mechanical advantage), and because of motor power limits, the best current robot has a vertical jumping agility of only 55% of a galago. Through use of a specialized leg mechanism designed to enhance power modulation, we constructed a jumping robot that achieved 78% of the vertical jumping agility of a galago. Agile robots can explore venues of locomotion that were not previously attainable. We demonstrate this with a wall jump, where the robot leaps from the floor to a wall and then springs off the wall to reach a net height that is greater than that accessible by a single jump. Our results show that series-elastic power modulation is an actuation strategy that enables a clade of vertically agile robots.
Locomoting soft robots typically walk or crawl slowly relative to their rigid counterparts. In order to execute agile behaviors such as jumping, rapid actuation modes are required. Here we present an untethered soft-bodied robot that uses a combination of pneumatic and explosive actuators to execute directional jumping maneuvers. This robot can autonomously jump up to 0.6 meters laterally with an apex of up to 0.6 meters (7.5 times it's body height) and can achieve targeted jumping onto an object. The robot is able to execute these directed jumps while carrying the required fuel, pneumatics, control electronics, and battery. We also present a thermodynamic model for the combustion of butane used to power jumping, and calculate the theoretical maximum work output for the design. From experimental results, we find the mechanical efficiency of this prototype to be 0.8%.
In this paper, we present the design and development of a miniature robot that is able to run and jump. This robot can use wheeled locomotion to travel on the flat ground. When it encounters a large obstacle compared to its size, it can stand up and leap over the obstacle. The robot has a mass of 25 grams and a maximum size of 9 centimeters. Experimental results show that with a take-off angle 80°, the robot can jump up to 1.44 meter in height and 0.59 meter in distance. Moreover, it has on-board energy, control, and communication abilities, which enables tetherless or autonomous operation. With the multi-modal locomotion abilities, the robot is expected to have many applications ranging from environmental monitoring, search and rescue, to military surveillance.
In this paper we describe a novel approach to the design and deployment of small and minimally actuated jumping or hopping robots that are suitable for exploring the unstructured terrains of celestial bodies. We introduce the basic jumping mobility paradigm, as well as the evolution of our hopping robot concept by way of the main prototypes that we have developed. These prototypes show that a small number of actuators can control the vehicle's steering, hopping, and self-righting motions. The last prototype is equipped with wheels so that precision motion can be combined with gross hopping motion. Lessons learned during the development of these prototypes have general applicability to the design of jumping robots. In addition to reviewing the issues relevant to the design of jumping systems, in this paper we describe some of the key mechanisms that enable our approach, we summarize tests obtained with these systems, and we present our future plans of localization and sensing for hopping mobility.
Unmanned ground vehicles are mostly wheeled, tracked, or legged. These locomotion mechanisms have a limited ability to traverse rough terrain and obstacles that are higher than the robot's center of mass. In order to improve the mobility of small robots it is necessary to expand the variety of their motion gaits. Jumping is one of nature's solutions to the challenge of mobility in difficult terrain. The desert locust is the model for the presented bio-inspired design of a jumping mechanism for a small mobile robot. The basic mechanism is similar to that of the semilunar process in the hind legs of the locust, and is based on the cocking of a torsional spring by wrapping a tendon-like wire around the shaft of a miniature motor. In this study we present the jumping mechanism design, and the manufacturing and performance analysis of two demonstrator prototypes. The most advanced jumping robot demonstrator is power autonomous, weighs and is capable of jumping to a height of covering a distance of .
Jumping locomotion has been widely employed in milliscale mobile robots to help overcome their size limitations by extending their range and enabling them to overcome obstacles. During jumping, the robot's legs experience acceleration that is up to an order of magnitude greater than the gravitational acceleration. This large force results in bending of the jumping legs. In this paper, we study how the bending of the leg affects the jumping performance of a flea-inspired jumping robot. To judge the effect of the leg compliance, the amount of energy lost during jumping is determined by examining the ratio of kinetic energy to input energy, which we define as the mechanical efficiency. The bending leg is dynamically modeled using a pseudo-rigid-body model in order to precisely analyze the energy transfer. Jumping experiments are performed for five different legs, each with a different stiffness. Shape memory polymer rivets, which are lightweight and compact, were used to easily switch out the legs. The mechanical efficiency of the robot with appropriately chosen leg compliance was 41.27% compared with 36.93% for the rigid case and 21.51% for the much more compliant case. The results show that optimizing the compliance of a jumping leg can improve the performance of a jumping robot.
This paper presents the design, development, and verification of a miniature integrated jumping and gliding robot, the MultiMo-Bat, which is inspired by the locomotion strategy of vampire bats. This 115.6 g robot exhibits high jumping and gliding performance, reaching heights of over 3 m, to overcome obstacles in the environment. The MultiMo-Bat was developed by a novel integrated design strategy that combines jumping and gliding locomotion modes and minimizes the necessary actuation and structural components by sharing a significant portion of the components required for each mode; nearly 70% of the total robot mass is utilized by both modes. This results in overall low mass, low volume, and high cooperation between the modes which allows for the preservation of over 80% of the performance of the independent jumping locomotion mode when combined. This not only allows for two high-performance locomotion modes, but also for all of the necessary actuation components to be on board. Key considerations and components of the design are discussed in the context of the integrated design approach. A prototype of the system is constructed and experimentally tested in various configurations to elucidate the overall system and integration performance. Finally, metrics are developed to begin to quantify the level and performance of the integrated approach as well as allow it to be compared to other mechanical and biological systems. This type of jumping and gliding robot can be used to explore, inspect, and monitor unstructured environments for security and environment monitoring applications.
The VelociRoACH is a 10 cm long, 30 gram hexapedal millirobot capable of running at 2.7 m/s, making it the fastest legged robot built to date, relative to scale. We present the design by dynamic similarity technique and the locomotion adaptations which have allowed for this highly dynamic performance. In addition, we demonstrate that rotational dynamics become critical for stability as the scale of a robotic system is reduced. We present a new method of experimental dynamic tuning for legged millirobots, aimed at finding stable limit cycles with minimal rotational energy. By implementing an aerodynamic rotational damper, we further reduced the rotational energy in the system, and demonstrated that stable limit cycles with lower rotational energy are more robust to disturbances. This method increased the stability of the system without detracting from forward speed.
Recent advances in small-scale flapping-wing micro aerial vehicles have extended the capabilities of flight control for a number of applications, such as intelligence, surveillance, and reconnaissance activities. In this work, we demonstrate autonomous flight control of a 13 gram ornithopter capable of flying toward a target without remote assistance. For autonomous flight control, we developed 1.0 gram control electronics integrated with a microcontroller, inertial and visual sensors, communication electronics, and motor drivers. We also developed a simplified aerodynamic model of ornithopter flight to reduce the order of the control system. With the aerodynamic model and the orientation estimation from on-board inertial sensors, we present flight control of an ornithopter capable of flying toward a target using onboard sensing and computation only. To this end, we developed a dead-reckoning algorithm to recover from the temporary loss of the target which can occur with a visual sensor with a narrow field of view. As a result, the 28 cm wing-span ornithopter flying toward a target landed within a radius of 0.5 m from the target with more than 85% success (N = 20).
Fleas can jump more than 200 times their body length. They do so by employing a unique catapult mechanism: storing a large amount of elastic energy and releasing it quickly by torque reversal triggering. This paper presents a flea-inspired catapult mechanism for miniature jumping robots. A robotic design was created to realize the mechanism for the biological catapult with shape memory alloy (SMA) spring actuators and a smart composite microstructure. SMA spring actuators replace conventional actuators, transmissions, and the elastic element to reduce the size. The body uses a four-bar mechanism that simulates a flea's leg kinematics with reduced degrees of freedom. Dynamic modeling was derived, and theoretical jumping was simulated to optimize the leg design for increased takeoff speed. A robotic prototype was fabricated with 1.1-g weight and 2-cm body size that can jump a distance of up to 30 times its body size.
The ability to jump is found widely among small animals such as frogs, grasshoppers, and fleas. They jump to overcome large obstacles relative to their small sizes. Inspired by the animals' jumping capability, a miniature jumping robot-Michigan State University (MSU) Jumper-has been developed. In this paper, the mechanical design, fabrication, and experimentation of the MSU jumper are presented. The robot can achieve the following three performances simultaneously, which distinguish it from the other existing jumping robots. First, it can perform continuous steerable jumping that is based on the self-righting and the steering capabilities. Second, the robot only requires a single actuator to perform all the functions. Third, the robot has a light weight (23.5 g) to reduce the damage that results from the impact of landing. Experimental results show that, with a 75° take-off angle, the robot can jump up to 87 cm in vertical height and 90 cm in horizontal distance. The robot has a wide range of applications such as sensor/communication networks, search and rescue, surveillance, and environmental monitoring.
This paper presents a bio-inspired design of a jumping mini robot including the theoretical analysis on jumping dynamics based on a simplified biological model, the dynamically optimized saltatorial leg design, the overall design of the jumping robot prototype and, as a part of the bio-mimetic research, and the measuring and comparing of the jumping characteristics between the robot and animal. The artificial saltatorial leg is designed to imitate the characteristics of a real jumping insect, kinematically and dynamically, and proposed to reduce the contact force at tarsus–ground interface during jumping acceleration thus optimizes the jumping motion by minimizing the risk of both leg ruptures and tarsus slippage. Then by means of high speed camera experiment, the jumping characteristics of the theoretical jumping model, the jumping insect leafhopper and the robot are compared so as to show the dynamic similarity and optimization results among them. The final energy integrated jumping robot prototype is able to accomplish a movement of continuous jumping, of which a single jumping reaches 100 mm high and 200 mm long, about twice and four times of its body length respectively.
Recent work suggests that wings can be used to prolong the jumps of miniature jumping robots. However, no functional miniature jumping robot has been presented so far that can successfully apply this hybrid locomotion principle. In this publication, we present the development and characterization of the ‘EPFL jumpglider’, a miniature robot that can prolong its jumps using steered hybrid jumping and gliding locomotion over varied terrain. For example, it can safely descend from elevated positions such as stairs and buildings and propagate on ground with small jumps. The publication presents a systematic evaluation of three biologically inspired wing folding mechanisms and a rigid wing design. Based on this evaluation, two wing designs are implemented and compared1.
This paper describes the numerical analysis and design for a higher jumping rescue robot using a pneumatic cylinder. First, the basic equations for jumping are derived and the simulation is performed. Then, the relationship between the jumping height and the pressure-receiving area of the cylinder is considered when the volume or the stroke of the cylinder is kept constant. This allows calculation of the optimal cross sectional area. In addition, the jumping height is also affected by the weight ratio between the rod and the cylinder tube. Based on these results, a robot equipped with a cylinder of the appropriate dimensions controlled by a well-selected valve is re-engineered and demonstrated. Experimental results show that the improved robot can jump considerably higher than the former design with the same energy efficiency, as shown in the following video. http://www.cm.ctrl.titech.ac.jp/study/jump/home.html.
This paper presents the design of a biologically inspired miniature integrated jumping and gliding robot capable of jumping heights of greater than 6 meters with a total weight of less than 100 grams. The robot is composed of two four-bar mechanisms that provide the structure for both jumping and gliding. The robot is highly integrated utilizing approximately 80% of the system mass for the jumping mode and 67% for the gliding mode. The drawbacks and benefits associated with the development of the integrated jumping and gliding prototype are highlighted and discussed. Finally, prototypes are constructed to test the integration strategy and validate the theoretical design.
We describe crawling and jumping by a deformable robot. Locomotion over rough terrain has been achieved mainly by rigid body systems including crawlers and leg mechanisms. This paper presents an alternative method of moving over rough terrain, one that employs deformation. First, we describe the principle of crawling and jumping as performed through deformation of a robot body. Second, in a physical simulation, we investigate the feasibility of the approach. Next, we show experimentally that a prototype of a circular soft robot can crawl and jump.
Keywords: deformation, locomotion, crawl, jump
In this paper we describe a novel approach to the design and deployment of small and minimally actuated jumping or hopping robots that are suitable for exploring the unstructured terrains of celestial bodies. We introduce the basic jumping mobility paradigm, as well as the evolution of our hopping robot concept by way of the main prototypes that we have developed. These prototypes show that a small number of actuators can control the vehicle's steering, hopping, and self-righting motions. The last prototype is equipped with wheels so that precision motion can be combined with gross hopping motion. Lessons learned during the development of these prototypes have general applicability to the design of jumping robots. In addition to reviewing the issues relevant to the design of jumping systems, in this paper we describe some of the key mechanisms that enable our approach, we summarize tests obtained with these systems, and we present our future plans of localization and sensing for hopping mobility.
We present here a three-dimensional FE model of the healthy human knee that included the main structures of the joint: bones, all the relevant ligaments and patellar tendon, menisci and articular cartilages. Bones were considered to be rigid, articular cartilage and menisci linearly elastic, isotropic and homogeneous and ligaments hyperelastic and transversely isotropic. Initial strains on the ligaments and patellar tendon were also considered. This model was validated using experimental and numerical results obtained by other authors. Our main goal was to analyze the combined role of menisci and ligaments in load transmission and stability of the human knee. The results obtained reproduce the complex, nonuniform stress and strain fields that occur in the biological soft tissues involved and the kinematics of the human knee joint under a physiological external load.
Jumping can be a very efficient mode of locomotion for small robots to overcome large obstacles and travel in natural, rough terrain. In this paper we present the development and characterization of a novel 5 cm, 7g jumping robot. It can jump obstacles more than 27 times its own size and outperforms existing jumping robots by one order of magnitude with respect to jump height per weight and jump height per size. It employs elastic elements in a four bar linkage leg system to allow for very powerful jumps and adjustment of the jumping force, take-off angle and force profile during the acceleration phase.
In this paper, we propose a new asymmetric robotic catapult based on the closed elastica. The conventional robotic catapults based on the closed elastica which the authors developed are the robotic elements for generating impulsive motions by utilizing a snap-through buckling. In a typical closed elastica, the two ends of an elastic strip are fixed to a passive rotational joint and an active rotational joint, respectively. Here we found that by adding only a range limitation to the passive rotational joint, compared to the conventional type, the deforming shape of the elastic strip becomes more complicated and 40% more elastic energy can be stored. Using this modification, we can develop a compact jumping robot which is able to leap over 700[mm] away and 200[mm] high.
/sup T/he University of Minnesota's Scout is a small cylindrical robot capable of rolling and jumping. Models describing the robot's motion are developed. These models can be employed for motion prediction and simulation. The results suggest that the determining factor of the Scout's behavior is the length of the winch cable.
Jump stabilization and landing control by wing-spreading of a locust-inspired jumper
- A Beck
- V Zaitsev
- U B Hanan
- G Kosa
- A Ayali
- A Weiss
A. Beck, V. Zaitsev, U. B. Hanan, G. Kosa, A. Ayali, and A. Weiss, "Jump
stabilization and landing control by wing-spreading of a locust-inspired
jumper," Bioinspiration Biomimetics, vol. 12, no. 6, 2017, Art. no. 066006.