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Modular Joint Design for Performance Enhanced Humanoid Robot LOLA.
Abstract
The paper presents the performance enhanced humanoid robot LOLA which is currently being manufactured. The goal of the project is the realization of a fast, human-like walking motion. The robot is characterized by its lightweight construction, a modular, multi-sensory joint design with brushless motors and an electronics architecture using decentralized joint controllers. The fusion of motor, gear and sensors into a highly integrated, mechatronic joint module has several advantages for the whole system, including high power density, good dynamic performance and reliability. Additional degrees of freedom are introduced in elbow, waist and toes. Linear actuators are employed for the knee joints for a better mass distribution in the legs
... Review on the works of foot structure for humanoid robots, we can list very old papers such as [19][20][21]. Recently, Sadedel et al. proposed a passive toe design. ...
... iter max , and niter denote the maximum iteration, and the nonlinear modulation index. Niter is defined in Eq. (19). n iter ¼ n min þ n max À n min ðÞ iter iter max (19) Where n max and n min are selected in the [0, 15] range. ...
... Niter is defined in Eq. (19). n iter ¼ n min þ n max À n min ðÞ iter iter max (19) Where n max and n min are selected in the [0, 15] range. n max and n min are 0.2 and 6.0, respectively. ...
This chapter addresses an approach to generate 3D gait for humanoid robots. The proposed method considers gait generation matter as optimization problem with constraints. Firstly, trigonometric function is used to produce trial gait data for conducting simulation. By collecting the result, we build an approximation model to predict final status of the robot in locomotion, and construct optimization problem with constraints. In next step, we apply an improve differential evolution algorithm with Gauss distribution for solving optimization problem and achieve better gait data for the robot. This approach is validated using Kondo robot in a simulated dynamic environment. The 3D gait of the robot is compared to human in walk.
... Early solutions in humanoid robots usually installed the weighted motors directly at the joints [1][2][3][4], with one motor on each actuated joint for the servocontrol of artificial articular joints. When based on a characteristic kinematic relationship, this solution also achieves independent servo motion control of each joint [1][2][3][4][5][6][7][8][9][10][11][12]. However, the joint articulation of humans features a complicated structure that is composed of tendons, bones, and muscles [13]. ...
... By using aspects of biomimetic inspiration, a proper transmission solution can be conceived with the articular actuation that locates the weighted actuator far away from the joint rotational center also with the aim to minimize the rotational inertia. In literature, existing solutions for ankle transmissions are reported within the mechanical application categories of gear transmissions, belt transmissions, and screw transmissions [1][2][3][4][5][6][7][8][9][10][11][12][16][17][18][19][20][21][22][23][24][25]. However, in literature and among existing humanoids, none shows an ankle design similar to the one proposed in the present study. ...
... In general, the servo motion control of artificial articular devices is obtained by rotational actuation through electrical servo motors [1][2][3][4][5][6][7][8][9]. This actuation layout usually requires gear sets or belts as linear transmission with speed reduction in angular motions. ...
In this paper, a mechanical transmission based on cable pulley is proposed for human-like actuation in the artificial ankle joints of human-scale. The anatomy articular characteristics of the human ankle is discussed for proper biomimetic inspiration in designing an accurate, efficient, and robust motion control of artificial ankle joint devices. The design procedure is presented through the inclusion of conceptual considerations and design details for an interactive solution of the transmission system. A mechanical design is elaborated for the ankle joint angular with pitch motion. A multi-body dynamic simulation model is elaborated accordingly and evaluated numerically in the ADAMS environment. Results of the numerical simulations are discussed to evaluate the dynamic performance of the proposed design solution and to investigate the feasibility of the proposed design in future applications for humanoid robots.
... Due to their advantages, PKM are used as sub mechanism modules in series-parallel hybrid robots in various fields such as humanoids, (THOR [6], LOLA [7], Charlie [8]), exoskeletons [9,10], haptic interface [11], surgeries [12], and industrial applications [13,14]), P r e p r i n t A recent work in mechanism design optimization is co-optimization with the motion trajectories [35]. In this approach, the design parameters and the motion equations are represented implicitly and efficient algorithms are used to explore the implicitly defined manifold. ...
... The lambda mechanism is a single closed loop (1-RRPR) mechanism and is used in the legged robots as an abstraction of revolute joint [7,61,62] as shown in figure 10. This mechanism is used for a stiffer actuation where a compact, but powerful force is required, and non-linear transmission characteristics are desirable. ...
The optimization of parallel kinematic manipulators (PKM) involve several constraints that are difficult to formalize, thus making optimal synthesis problem highly challenging. The presence of passive joint limits as well as the singularities and self-collisions lead to a complicated relation between the input and output parameters. In this article, a novel optimization methodology is proposed by combining a local search, Nelder–Mead algorithm, with global search methodologies such as low discrepancy distribution for faster and more efficient exploration of the optimization space. The effect of the dimension of the optimization problem and the different constraints are discussed to highlight the complexities of closed-loop kinematic chain optimization. The work also presents the approaches used to consider constraints for passive joint boundaries as well as singularities to avoid internal collisions in such mechanisms. The proposed algorithm can also optimize the length of the prismatic actuators and the constraints can be added in modular fashion, allowing to understand the impact of given criteria on the final result. The application of the presented approach is used to optimize two PKMs of different degrees of freedom.
... Due to their advantages, PKM are used as sub mechanism modules in series-parallel hybrid robots in various fields such as humanoids, (THOR [6], LOLA [7], Charlie [8]), exoskeletons [9,10], haptic interface [11], surgeries [12], and industrial applications [13,14]), see [15] for an extensive survey. PKMs are also prominently employed in high speed industrial assembly lines, for example the DELTA + 1 DOF wrist robot [16]. ...
... The lambda mechanism is a single closed loop (1-RRPR) mechanism and is used in the legged robots as an abstraction of revolute joint [7,61,62] as shown in figure 10. This mechanism is used for a stiffer actuation where a compact, but powerful force is required, and non-linear transmission characteristics are desirable. ...
The optimization of parallel kinematic manipulators (PKM) involve several constraints that are difficult to formalize, thus making optimal synthesis problem highly challenging. The presence of passive joint limits as well as the singularities and self-collisions lead to a complicated relation between the input and output parameters. In this article, a novel optimization methodology is proposed by combining a local search, Nelder-Mead algorithm, with global search methodologies such as low discrepancy distribution for faster and more efficient exploration of the optimization space. The effect of the dimension of the optimization problem and the different constraints are discussed to highlight the complexities of closed-loop kinematic chain optimization. The work also presents the approaches used to consider constraints for passive joint boundaries as well as singularities to avoid internal collisions in such mechanisms. The proposed algorithm can also optimize the length of the prismatic actuators and the constraints can be added in modular fashion, allowing to understand the impact of given criteria on the final result. The application of the presented approach is used to optimize two PKMs of different degrees of freedom.
... [18] , Stewart platform, 2SPU+1U 1 [20] , double parallelogram linkage [21] etc. have been used in various hybrid robots like hominid Charlie [22] , multi-legged robot Mantis [23] , Recupera full body exoskeleton [24] , AXO-SUIT [25] as well as humanoid robots like Lola [26] and THOR [27] . The design motivation of such hybrid robots is evident: use of PKM-based submechanisms helps designers to achieve lightweight, modular and compact design while enhancing the stiffness and dynamic characteristics of the robot. ...
... Both of these properties can be achieved by utilizing parallel mechanisms in the design. Fig. 2 a shows the bipedal robot Lola [26] developed in 2006 by TU Munich, which is probably the first humanoid robot designed using a modular parallel joint concept. The non-linear transmission between the actuator space and output space in a parallel mechanism can be utilized advantageously by adjusting its design parameters to the torque-speed characteristics of typical movements of the robot [33] . ...
Parallel mechanisms are used increasingly often as modular subsystem units in various robots and man-machine interfaces for their superior stiffness, payload-to-weight ratio and dynamic properties. This leads to series-parallel hybrid robotic systems which utilize closed loop linkages and parallel kinematic machines as an abstraction of a certain kinematic joint. This paper presents a survey of recently developed series-parallel hybrid robots in various application domains such as legged robotics, humanoids, exoskeletons and industrial automation. In particular, we focus on modular and distributive aspects of such systems with an intention to bring the current design paradigm into focus, which simplifies the robot development process by promoting the effective reuse of hardware and software components and overcomes the shortcomings of traditional serial robots like poor payload capacity and stiffness.
... To combine the various advantages of serial and parallel topologies, many series-parallel hybrid designs, primarily in the field of legged robotics, have been developed in the last decade (see Fig. 1). Fig. 1a shows the bipedal robot LOLA [1] which is probably the first humanoid robot designed using a modular joint concept utilizing parallel kinematics. The design of NASA Valkyrie humanoid [2] followed a similar design concept by utilizing parallel kinematics for its wrist, torso and ankle joints. ...
... The full model of the leg (T ) has m = 6 independent degrees of freedom, p = 6 active joints and n = 18 spanning tree joints. Further, we introduce three different model simplifications from the full description of the robot: 1)T 1 is a subgraph of T containing only the independent joints neglecting all other branches, 2)T 2 is a subgraph of T containing only the independent joints where bodies separated by the cut joints in T are merged to parent and child links of each parallel submechanism module with the help of fixed joints 1 , 3)T 3 is a subgraph of T which 1 It should be noted that the total mass ofT 1 is less than T andT 2 and T have equal masses. ...
It is becoming increasingly popular to use parallel mechanisms as modular subsystem units in the design of various robots for their superior stiffness, payload-to-weight ratio and dynamic properties. This leads to series-parallel hybrid robotic systems which pose several challenges in their modeling and control e.g. resolution of loop closure constraints, large size of their spanning tree etc. These robots are typically position-controlled and when equipped with real time dynamic control, often a simplified inverse dynamic model of these systems is utilized. However, the trade-offs of this model simplification has not been studied previously. This paper presents a representative study of the neglected dynamics by introducing some error metrics which are useful in highlighting the advantages and disadvantages of such model simplification. The study is guided with the help of a series-parallel humanoid leg which has been recently developed at DFKI-RIC.
... Those reasons make e.g. the Delta-robot a remarkable representative of PMs (see [23]). In the context of humanoid robotics and exoskeletons, PMs have been used as a mechanical generator of certain kinematic joints such as in torso, wrist, hip and ankle [14,15,18,24]. PMs possess different types of singularities as described in [7]. ...
... Motivation: VIAs allow for independent position and stiffness control of one DOF joints by using two actuators. Following the trend of highly integrated multi-DOF joints in robotics (see [14,15,18,24]), it will be desirable to have multi-DOF variable impedance joints. However, utilizing two actuators per joint in a serial architecture may significantly increase the weight of the robot and reduce its dynamic performance. ...
Future robots will rely more than today on high precision, better energy efficiency and safe handling (e.g. human-machine interaction). An inevitable step in the development of new robots is therefore the improvement of existing mechanisms, since better sensors and algorithms do not satisfy the demands alone. During the last three decades, Parallel Redundant Mechanisms (PRM) came more into the focus of research, as they are advantageous in terms of singularity avoidance , fast movements and energy efficiency. Subsequently, yet another technology-the Variable Impedance Actuator (VIA)-emerged which proposes to change its inherent stiffness allowing an adaptation to its environment and to handle for example dynamic movements or shock absorptions. This work aims to create a new mechanism where a stiffness and position control for 2 degrees of freedom (DOF) is achieved by 3 actuators with flexible elements. It is thus a combination of the PRM and VIA, while taking advantage of both technologies but asking for a more sophisticated mathematical description. Practical implementation is intended for a humanoid ankle mechanism. Kinetostatic and stiffness models are derived and incorporated into the simulation of the mechanism. The simulations show that improvements in terms of singularity removal and dexterity are achieved. Furthermore, the adaptation of human like gait performances is presented.
... A maximum walking speed of 1.25 km/h was achieved by KHR-3 prototype [10]. In Germany, the Technical University of Munich (TUM) developed two humanoid prototypes, Johnnie with a walking speed of 2 km/h and Lola [11][12][13][14]. A 41-DoF humanoid robot Reem-B developed by Pal Technology Robotics in Spain reaches walking speed of 1.5 km/h [15]. ...
... where is the transmission ratio of harmonic reducer, is the motor torque constant and is the motor current. At the knee and ankle joints, transmission kinematics given in Equations (12)(13)(14)(15)(16)(17)(18)(19)(20) in Section 3 are used to compute corresponding joint torque. ...
This paper presents the design and construction of a 12-DoF biped walking robot. The kinematics of electrically actuated 6-DoF legs is similar to that of human legs with three DoF at the hip, one at the knee and two at the ankle joints. The mechanical design of the robot was based on dynamical simulations realized in a modular PC environment. Two communicating software were used in order to solve the forward dynamics of the system and to design walking controllers. Forward, backward and lateral walking as well as stair climbing behaviors with up to 6 km/h forward walking speeds have been simulated in order to determine the nominal power rates required at joints. Hip joints are actuated by DC motors coupled to harmonic reducers situated both in joint axes. The actuators driving the knee and ankle joints are situated higher than the respective joint axes and the rotational output motion of DC motors are transmitted to the joints through linear ball-screw mechanisms. Spherical joints are used within the transmission of spatial motion required for the 2-DoF at ankle joints. All joints consist of absolute encoders and 6-axes force/torque transducers are mounted at the ankle joints. The robot is controlled through an embedded industrial PC running real-time operating system. All electronic control hardware including the motor drivers and sensors communicate through CAN bus. The robot’s mass without batteries is 55 kg and its height is 142 cm.
... To reduce the total mass in combination with high robustness, we can use adapted bearing concepts. Lohmeier et al. describe in [7] a joint design of the robot LOLA. For this approach, Lohmeier et al. use a cross roller bearing. ...
A manipulator with a human-like range of motion combined with adequate control strategies can increase the autonomy of humanoid robots. If we look at the motion patterns of human beings during manipulation, we see that they often combine trunk and manipulator motion to grasp objects lying outside the workspace of the manipulator itself. In this work, we introduce an approach for a hybrid inverse kinematics algorithm with a focus on avoiding joint and workspace limitations. We combine a fully analytical inverse kinematics algorithm for a redundant 7-DOF manipulator with the inverse kinematics of the robot’s trunk. To handle the workspace limitations, if a desired pose lies outside the workspace, we combine the robot’s trunk motion with the manipulator motion. We demonstrate the performance of our approach with the humanoid robot Sweaty, playing fully autonomously a chess game against a human while picking up chess pieces lying outside the workspace of its manipulator by a combined trunk and manipulator motion.
... These humanoid robots are making drastic accomplishments and improvements with the passage of time; specifically, their mechanical and electronic designs are their basic building blocks. There are some prominent robot designs summarized in Table 1 with respect to their design complexities, features, usage, etc. Humanoid robots such as ARMAR [24,25], JUSTIN [26,[26][27][28], BHR-5 [29], and LOLA [30][31][32][33] are very complex and efficient designs, and most of them have a desktop application interface to control the robot. As different designs are reviewed, different applications in healthcare are found. ...
The COVID-19 pandemic took valuable lives all around the world. The virus was so contagious and lethal that some of the doctors who worked with COVID-19 patients either were seriously infected or died, even after using personal protective equipment. Therefore, the challenge was not only to help communities recover from the pandemic, but also to protect the healthcare staff/professionals. In this regard, this paper presents a comprehensive design of a customized pseudo-humanoid robot to specifically deal with contagious patients by taking basic vitals through a healthcare staff member from a remote location amid the COVID-19 pandemic. The proposed design consists of two portions: (1) a complete design of mechanical, electrical/electronic, mechatronic, control, and communication parts along with complete assembly to make a complete multitask-performing robot that interacts with patients to take vitals, termed as RoboDoc, and (2) the design of the healthcare staff side (master/operator side) control of a joystick mechanism with haptic feedback. The proposed RoboDoc design can be majorly divided into three parts: (1) the locomotion part is composed of two-wheeled DC motors on a rover base and two omni wheels to support the movements of the robot; (2) the interaction part consists of a single degree-of-freedom (s-DOF) neck to have communication with different heights of patients and (3) two anthropomorphic arms with three degrees-of-freedom (3-DOF). These parts help RoboDoc to reach to patient’s location and take all of the vitals using relevant devices such as an IR temperature thermometer, pulse oximeter, and electronic stethoscope for taking live auscultations from the lungs and heart of the patient. The mechanical design was created using solid works, and the electronic control design was made via proteus 8.9. For haptic teleoperation, an XBOX 360 controller based on wireless communication is used at the master/operator side. For the convenience of the healthcare staff (operator), an interactive desktop-based GUI was developed for live monitoring of all the vital signs of patients. For the remote conversation between the healthcare staff and the patient, a tablet is mounted (that also serves as the robot’s face), and that tablet is controlled via a mobile application. For visual aid, a DSLR camera is integrated and controlled remotely, which helps the doctor monitor the patient’s location as well as examine the patient’s throat. Finally, successful experimental results of basic vitals of the remote patient such as temperature sensing, pulse oximeter, and heart rate (using haptic feedback) were obtained to show the significance of the proposed cost-effective RoboDoc design.
... Recently, the field of industrial and humanoid robots has also begun to consider hybrid designs. The robot LOLA [4] presented in 2006 by TU Munich is regarded as the first humanoid robot designed with a serial-parallel hybrid system that includes PKMs at knees and ankles. In 2010, the DFKI-RIC introduced AILA [5], a mobile dual-arm manipulation robot with hybrid design, which involves parallel joints at the wrists, neck and torso. ...
Recent studies suggest that a stiff structure along with an optimal mass distribution are key features to perform dynamic movements, and parallel designs provide these characteristics to a robot. This work presents the new upper-body design of the humanoid robot RH5 named RH5 Manus, with series-parallel hybrid design. The new design choices allow us to perform dynamic motions including tasks that involve a payload of 4 kg in each hand, and fast boxing motions. The parallel kinematics combined with an overall serial chain of the robot provides us with high force production along with a larger range of motion and low peripheral inertia. The robot is equipped with force-torque sensors, stereo camera, laser scanners, high-resolution encoders etc that provide interaction with operators and environment. We generate several diverse dynamic motions using trajectory optimization, and successfully execute them on the robot with accurate trajectory and velocity tracking, while respecting joint rotation, velocity, and torque limits.
... The modernized form of these bipedal walking robots is called a humanoid robot. They are either designed for entertainment, logistics, collaborative maintenance in the industries, and also teleoperation [12][13][14][15][16][17]. To this end, researchers have taken motivation from 2D designs, 3D bipedal robots, and humanoid robots to design exoskeleton robots for bipedal walking. ...
Exoskeleton robots are electrically, pneumatically, or hydraulically actuated devices that externally support the bones and cartilage of the human body while trying to mimic the human movement capabilities and augment muscle power. The lower extremity exoskeleton device may support specific human joints such as hip, knee, and ankle, or provide support to carry and balance the weight of the full upper body. Their assistive functionality for physically-abled and disabled humans is demanded in medical, industrial, military, safety applications, and other related fields. The vision of humans walking with an exoskeleton without external support is the prospect of the robotics and artificial intelligence working groups. This paper presents a survey on the design and control of lower extremity exoskeletons for bipedal walking. First, a historical view on the development of walking exoskeletons is presented and various lower body exoskeleton designs are categorized in different application areas. Then, these designs are studied from design, modeling, and control viewpoints. Finally, a discussion on future research directions is provided.
... However, such designs also have recently caught the attention of robotics researchers from industry and academia (see [2] for an extensive survey). For instance, the LOLA humanoid robot [3] has a spatial slider crank mechanism in the knee joint and a two degree of freedom (DOF) rotational parallel mechanism in the ankle joint. Similarly, the AILA humanoid 1 The authors are with the Robotics Innovation Center, DFKI GmbH, 28359 Bremen, Germany. ...
... Within a robot, there are an immense amount of configurable parameters and actuation strategies. Many roboticists, seeking to take advantage of the energetically economical motion that animals exhibit across a wide range of speeds [57,51,85], design their robots based on animals [80,10,64]. The motivating idea is that features that are useful in nature should be similarly useful in robotics. ...
There exist many open design questions in the field of legged robotics. Should leg extension and retraction occur with a knee or a prismatic joint? Will adding a compliant ankle lead to improved energetics compared to a point foot? Should quadrupeds have a flexible or a rigid spine? Should elastic elements in the actuation be placed in parallel or in series with the motors? Though these questions may seem basic, they are fundamentally difficult to approach. A robot with either discrete choice will likely need very different components and use very different motion to perform at its best. To make a fair comparison between two design variations, roboticists need to ask, is the best version of a robot with a discrete morphological variation better than the best version of a robot with the other variation? In this dissertation, I propose to answer these type of questions using an optimization based approach. Using numerical algorithms, I let a computer determine the best possible motion and best set of parameters for each design variation in order to be able to compare the best instance of each variation against each other. I developed and implemented that methodology to explore three primary robotic design questions. In the first, I asked if parallel or series elastic actuation is the more energetically economical choice for a legged robot. Looking at a variety of force and energy based cost functions, I mapped the optimal motion cost landscape as a function of configurable parameters in the hoppers. In the best case, the series configuration was more economical for an energy based cost function, and the parallel configuration was better for a force based cost function. I then took this work a step further and included the configurable parameters directly within the optimization on a model with gear friction. I found, for the most realistic cost function, the electrical work, that series was the better choice when the majority of the transmission was handled by a low-friction rotary-to-linear transmission. In the second design question, I extended this analysis to a two-dimensional monoped moving at a forward velocity with either parallel or series elastic actuation at the hip and leg. In general it was best to have a parallel elastic actuator at the hip, and a series elastic actuator at the leg. In the third design question, I asked if there is an energetic benefit to having an articulated spinal joint instead of a rigid spinal joint in a quadrupedal legged robot. I found that the answer was gait dependent. For symmetrical gaits, such as walking and trotting, the rigid and articulated spine models have similar energetic economy. For asymmetrical gaits, such as bounding and galloping, the articulated spine led to significant energy savings at high speeds. The combination of the above studies readily presents a methodology for simultaneously optimizing for motion and morphology in legged robots. Aside from giving insight into these specific design questions, the technique can also be extended to a variety of other design questions. The explorations in turn inform future hardware development by roboticists and help explain why animals in nature move in the ways that they do.
... However, such designs also have recently caught the attention of robotics researchers from industry and academia (see [2] for an extensive survey). For instance, the LOLA humanoid robot [3] has a spatial slider crank mechanism in the knee joint and a two DOF rotational parallel mechanism in the ankle joint. Similarly, the AILA humanoid robot [4] employs parallel mechanisms for its wrist, neck, and torso joints. ...
Last decades of humanoid research has shown that humanoids developed for high dynamic performance require a stiff structure and optimal distribution of mass--inertial properties. Humanoid robots built with a purely tree type architecture tend to be bulky and usually suffer from velocity and force/torque limitations. This paper presents a novel series-parallel hybrid humanoid called RH5 which is 2 m tall and weighs only 62.5 kg capable of performing heavy-duty dynamic tasks with 5 kg payloads in each hand. The analysis and control of this humanoid is performed with whole-body trajectory optimization technique based on differential dynamic programming (DDP). Additionally, we present an improved contact stability soft-constrained DDP algorithm which is able to generate physically consistent walking trajectories for the humanoid that can be tracked via a simple PD position control in a physics simulator. Finally, we showcase preliminary experimental results on the RH5 humanoid robot.
... In the Italian Institute of Technology, the iCub robot [8][9][10][11] was designed based on children, and it has 53 driving degrees of freedom. The LOLA robot was developed by a team in the University of Munich, Germany [12], and this robot contains actively driven toe joints, which has improved the stability of the robot's feet on and off the ground. Despite the progress achieved in the design of humanoids/bipeds, there are still some significant barriers such as how to prevent robots (physical structure, materials, actuation, and sensing) from emulating the physical performance of the human body. ...
This paper presents a novel framework of hydraulic-driven biped robot. The target biped robot is a humanoid robot NWPUBR-1 with 12 degrees of freedom (DOF), and its dimensions are close to that of an average male. The joint axis adopts the modular structure design of sensor with angle measurement, and the force sensor is deployed on the side of hydraulic actuator to facilitate force and position control of the robot. Meanwhile, the finite element analysis of critical components is conducted to meet the requirements of mechanical strength in motion. Based on the screw theory, the forward kinematics and Jacobian matrix models are established, and the inverse kinematics of robot is solved by using the analytical geometric method. To achieve real-time control of the robot gait in 3D space, a three-dimensional linear inverted pendulum model (3D-LIPM) is built, and a 3D gait model is generated by combining the zero-moment point (ZMP) theory. In the virtual environment of MATLAB software, the results of programming simulation show that the biped robot can walk stably in the virtual environment, which proves the correctness of 3D-LIPM.
... This work presents the workspace analysis with some assumptions in the architecture. This architecture has been widely proposed in past research for various applications [32,33,34,35,36]. Other variant of the architecture is the 2PUS-1U which has been implemented in the Valkyrie humanoid [37]. ...
The use of endoscope in otological surgery provides many benefits in terms of visibility and access to the operating region but needs to be handled by the surgeon at all time making such surgeries cumbersome. A mechanism that can act as an assistant to the surgeon for manipulating endoscope can have a huge positive impact on the efficiency of the surgeon and the surgeries.
This thesis explains the technical requirements, constraints and optimization process for proposing a mechanism for such application. The importance of analysis and synthesis of the kinematic properties of the structure for an optimized output is highlighted in the study. The author presents a novel implementation of an optimization algorithm for the design optimization. Various approaches researched in the past for the optimization are presented and their advantages and disadvantages are pointed out too. The effect of parametrization, different constraints as well as rewarding strategies are discussed to stress the complexities in the optimization of closed loop kinematic chains. The thesis also presents approaches used to consider the constraints for the passive joint limits as well as avoiding internal collision in the mechanism. A novel methodology is used for a faster and efficient global search of the optimization space. The work concludes by presenting the optimised result as well as by discussing open questions regarding the future of mechanism design.
... If a z-phase output exists on the incremental encoder, the absolute position can be measured using the z-phase output, but this is only possible when the incremental encoder rotates until a point at which the z-phase is detected and still requires a reference position (Lim and Lee 2014). Therefore, it is utilized with other sensors that can measure absolute positions, for example, absolute encoder, resolver, potentiometer, etc. (Choi et al. 2013;Lohmeier et al. 2006). The absolute encoder possesses a complex disk pattern called gray code and can detect the absolute position of the disk. ...
The dual absolute encoder (DAE) system is a measurement system for a motion control system that comprises two absolute encoders and one reduction mechanism. In terms of accuracy and measuring range, DAE is superior to ordinary dual encoder systems, which comprise one incremental encoder, one absolute encoder, and a reduction mechanism. In this study, we focus on the error measurement and compensation using DAE system. There have been many studies to measure and compensate for the errors in measuring systems. However, this typically demands high precision equipment to measure the errors, and attaching and detaching the equipment affects the errors. We measured the errors in the absolute encoder by using the DAE systems solely. The measured errors are modeled using harmonic functions and compensated for by using the modeled errors. The experimental results reveal that the maximum errors and mean absolute errors decrease by one-seventh and one-twelfth, respectively, after error compensation. As a result, we can compensate the errors in the encoders with the encoder system, itself. Additionally, the modeled errors in a DAE system are observed to remain constant even when changing the reduction ratios between two absolute encoders. Once the errors are measured and modeled in the DAE system, the modeled errors can be applied to a DAE system with a different reduction ratio for error compensation.
... Advances in DC motor, SEA, and hydraulic servo valve designs have also pushed the envelope in the performance capabilities of bipedal and humanoid machines. Taking insights from the design of JOHNNIE (Gienger et al., 2001), researchers at the Technical University of Munich designed the 25 DoF humanoid LOLA (Lohmeier et al., 2006) to study fast human-like walking. LOLA (Figure 1.11) is 180 cm tall and weights approximately 55 kg. ...
Inspired by the remarkable locomotion capabilities illustrated by animals across land, sea and air, robotics engineers have strived for decades to achieve similar dynamic locomotion capabilities in legged machines. Learning from animals’ compliant structures and ways of utilizing them, engineers have developed numerous novel mechanisms that allow for more dynamic, more efficient legged systems. These newly emerging robotic systems possess distinguishing mechanical characteristics in contrast to manufacturing robots in factories and pave the way for a new era of mobile robots to serve our society. Realizing the full capabilities of these new legged robots is a multi-factorial research problem, requiring coordinated advances in design, control, perception, state estimation, navigation and other areas. Design of Dynamic Legged Robots focuses on the mechanical design of legged robots. It introduces the topic by looking at the history of legged robots, taking us up to the dynamic legged machines that are today pushing the boundaries of speed and performance through advances in materials, design, and control. It goes on to discuss some of the main challenges to actuator design in legged robots and discusses a recently developed technology called proprioceptive actuators in order to meet the needs of today’s legged machines. It proceeds to discuss philosophical perspectives on designing for energetic efficiency, a critical aspect of legged robot design. The penultimate chapter discusses trends in leg design and presents a case study using principles from observations in biology to design a leg for the MIT Cheetah robot, and concludes with a summary of future directions and applications.
... Fig. 1 shows some of the series-parallel hybrid walking robots developed in the last decade. Fig. 1a shows the bipedal robot LOLA [4] which is probably the first humanoid robot designed us-ing a modular joint concept utilizing parallel mechanisms. The design of NASA Valkyrie humanoid [5] followed a similar design concept by utilizing parallel mechanisms for its wrist, torso and ankle joints. ...
Parallel mechanisms are increasingly being used as modular subsystem units in various robots and man-machine interfaces for their superior stiffness, payload-to-weight ratio and dynamic properties. This leads to series-parallel hybrid robotic systems which are challenging to model and control due to the presence of various closed loops. Most model based kinematic and dynamic modeling tools resolve loop closure constraints numerically and hence suffer from inefficiency and accuracy issues. Also, they do not exploit the modularity in robot design. In this paper, we present a modular and analytical approach towards kinematic and dynamic modeling of series-parallel hybrid robots. This approach has been implemented in a software framework called Hybrid Robot Dynamics (HyRoDyn) and its application is demonstrated with the help of a series-parallel hybrid humanoid robot recently developed at DFKI-RIC.
... Irrespective of the drive system used to actuate a robot for a specific task, there is the need to accurately measure the angle, speed and acceleration of a joint [14] and in some cases, to have a 2 measurement system of the angle in order to ensure improved accuracy and precision of measurement results in case one measurement system fails in safety-critical applications. In this work, an angle and speed measurement system using an incremental rotary encoder connected to a prototype robotic joint was designed, developed and tested. ...
The design of a prototype system that measures the joint angles of the rotary joint of a robotic exoskeleton is presented in this work. An incremental rotary encoder is a sensor that can be connected to any rotary joint to measure the angle of rotation, speed of rotation, direction of rotation (clockwise or counter-clockwise motion) as well as the acceleration of a joint. The measurement system using a rotary encoder which generates an electrical signal either analog or digital according to the rotation movement was designed in this work. A prototype rotary joint having a 270° range of motion was fabricated with ABS plastic using 3D printing and then connected to an incremental rotary encoder to measure its speed and angle of motion. A robotic exoskeleton was then proposed to be used with the tested and developed measurement system.
... Other important electric or hydraulic full and half-size humanoids, include the LOLA/Johnnie robot [6], the iCub [7] and cCub/COMAN [8] half-size humanoids, the full-size Valkyrie humanoid [9], TORO [10] and M2V2 biped [11], JAXON [12], Hydra [13], Escher [14], TALOS [15], and WALK-MAN [16] humanoids. Several other companies have also presented very impressive humanoid or bipedal systems, such as SHAFT, Robotis THORMANG, Agility Robotics Cassie biped, and Boston Dynamics PETMAN/ATLAS. ...
This paper provides the design of a novel open-hardware mini-bipedal robot, named Rapid-Prototyped Remote-Brain BiPed (RPBP), that is developed to provide a low-cost and reliable platform for locomotion and perception research. The robot is made of customized 3D-printed material (ABS plastic) and electronics, and commercial Robotics Dynamixel MX-28 actuators, as well as visual RGB-D and IMU sensing systems. We show that the robot is able to perform some locomotion/visual-odometry tasks and it is easy to switch between different feet designs, providing also a novel Center-of-Pressure (CoP) sensing system, so that it can deal with various types of terrain. Moreover, we provide a description of its control and perception system architecture, as well as our opensource software packages that provide sensing and navigation tools for locomotion and visual odometry on the robot. Finally, we briefly discuss the transferability of some prototype research that has been done on the developed mini-biped, to half or fullsize humanoid robots, such as COMAN or WALK-MAN.
... Fig. 1 shows some of the series-parallel hybrid robots developed in the last decade. Fig. 1a shows the bipedal robot LOLA [3] which is probably the first humanoid robot designed using a modular joint concept utilizing parallel mechanisms. The design of NASA Valkyrie humanoid [4] followed a similar design concept by utilizing parallel mechanisms for its wrist, torso and ankle joints. ...
Parallel mechanisms are increasingly being used as modular subsystem units in various robots and man-machine interfaces for their superior stiffness, payload-to-weight ratio and dynamic properties. This leads to series-parallel hybrid robotic systems which are difficult to model and control due to the presence of various closed loops. Most model based kinematic and dynamic modeling tools resolve loop closure constraints numerically and hence suffer from inefficiency and accuracy issues. Also, they do not exploit the modularity in robot design. In this paper, we present a modular and analytical approach towards kine-matic and dynamic modeling of series-parallel hybrid robots. This approach has been implemented in a software framework called Hybrid Robot Dynamics (HyRoDyn) and its application is demonstrated with the help of a series-parallel hybrid humanoid robot recently developed at DFKI-RIC.
... Other important electric or hydraulic full and half-size humanoids, include the LOLA/Johnnie robot [6], the iCub [7] and cCub/COMAN [8] half-size humanoids, the full-size Valkyrie humanoid [9], TORO [10] and M2V2 biped [11], JAXON [12], Hydra [13], Escher [14], TALOS [15], and WALK-MAN [16] humanoids. Several other companies have also presented very impressive humanoid or bipedal systems, such as SHAFT, Robotis THORMANG, Agility Robotics Cassie biped, and Boston Dynamics PETMAN/ATLAS. ...
This paper provides the design of a novel open-hardware mini-bipedal robot, named Rapid-Prototyped Remote-Brain BiPed (RPBP), that is developed to provide a low-cost and reliable platform for locomotion and perception research. The robot is made of customized 3D-printed material (ABS plastic) and electronics, and commercial Robotics Dy-namixel MX-28 actuators, as well as visual RGB-D and IMU sensing systems. We show that the robot is able to perform some locomotion/visual-odometry tasks and it is easy to switch between different feet designs, providing also a novel Center-of-Pressure (CoP) sensing system, so that it can deal with various types of terrain. Moreover, we provide a description of its control and perception system architecture, as well as our open-source software packages that provide sensing and navigation tools for locomotion and visual odometry on the robot. Finally, we briefly discuss the transferability of some prototype research that has been done on the developed mini-biped, to half or full-size humanoid robots, such as COMAN or WALK-MAN.
... Similarly KAIST built KHR-1/2/3 (Hubo) [6] and Waseda continued its long and successful tradition to build many different models through to Wabian-2R [7]. The iCub humanoid represents a coordinated European effort in the humanoid arena aiming at producing a "child-like" humanoid platform for understanding and development of cognitive systems [8][9][10][11], but other successful humanoid/bipedal implementations within Europe include the humanoid LOLA which is an enhancement over the Johnnie robot [12]. Despite the progress made in the design of humanoids/bipeds, significant barriers still remain that prevent robots (physical structure, materials, actuation, and sensing) from emulating the physical performance capabilities of the human body. ...
... Similarly KAIST built KHR-1/2/3 (Hubo) (Park et al. 2007), Waseda continued its long and successful tradition to build many different models through to Wabian-2R (Ogura et al. 2006) and University of Tokyo look at improving the power performance of humanoids (Ito et al. 2012). The iCub humanoid represents a co-ordinated European effort in the humanoid arena aiming at producing a child-size humanoid platform for understanding and development of cognitive systems (Tsagarakis et al. 2007;Parmiggiani et al. 2012), but other successful humanoid/bipedal implementations within Europe include the humanoid LOLA which is an enhancement over the Johnnie robot (Lohmeier et al. 2006) and the recently developed torque controlled humanoid TORO (Englsberger et al. 2014). ...
In this chapter we present WALK-MAN, a humanoid platform that has been developed to operate in realistic unstructured environments and demonstrate new skills including powerful manipulation, robust balanced locomotion, high strength capabilities and physical sturdiness. To enable these capabilities, WALK-MAN design and actuation are based on the most recent advancements of Series Elastic Actuation (SEA) drives with unique performance features that differentiate the robot from previous state-of-the-art compliant actuated robots. Physical interaction performance benefits from both active and passive adaptation thanks to WALK-MAN actuation, which combines customized high performance modules with tuned torque/velocity curves and transmission elasticity for high speed adaptation response and motion reactions to disturbances. The WALK-MAN design also includes innovative design optimization features that consider the selection of kinematic structure and the placement of the actuators with respect to the body structure to maximize the robot performance. Physical robustness is ensured with the integration of elastic transmission, proprioceptive sensing and control. WALK-MAN hardware was designed and built in 11 months, and the prototype of the robot was ready 4 months before the DARPA Robotics Challenge (DRC) Finals. The motion generation of WALK-MAN is based on the unified motion generation framework of whole-body locomotion and manipulation (termed loco-manipulation). WALK-MAN is able to execute simple loco-manipulation behaviours synthesized by combining different primitives defining the behaviour of the center of gravity, of the hands, legs and head, the body attitude and posture, and the constrained body parts such as joint limits and contacts. The motion generation framework including the specific motion modules and software architecture are discussed in detail. A rich perception system allows the robot to perceive and generate 3D representations of the environment as well as detect contacts and sense physical interaction force and moments. The operator station that pilots use to control the robot provides a rich pilot interface with different control modes and a number of tele-operated or semi-autonomous command features. The capability of the robot and the performance of the individual motion control and perception modules were validated during the DARPA Robotics Challenge in which the robot was able to demonstrate exceptional physical resilience and execute some of the tasks during the competition.
... LOLA robot [30], successor of the German robot Johnnie, is recognized by another revolute joint arround the roll axis at the trunk. This articulation could make it possible to walk by unfolding the knee at certain moments of the cycle, as does the human being. ...
My thesis aims at contributing to the development and improvement of the upper body of HYDROïD robot for bi-manual tasks, while basing on a bio-mechanical study of this part of the human being. To reach our major goal, this work adopts, at first, a novel hybrid structure of 4 degrees of freedom (DOF) for the trunk of the robot, distributed in three DOF at the lumbar level and one DOF at the thoracic level. This structure was identified after an analysis of the work-space of a multi-body model feigning the vertebral column of a human being, and an optimization study of that model allowing the synthesis of the envisaged structure. Secondly, an improvement of the kinematics of the robor arm was organized, by introducing the notion of the shoulder complex in the present structure. The choice of this new degree of freedom was the fruit of a systematic approach to increase the anthropomorphism geometry of the arm wished towards a humanitarian arm of the same size.The two proposed structures crossed afterward by the mechanical design phase while respecting all the geometrical constraints and by using the hydraulic energy as being the type of actuation of these systems. Finally, the Inverse Geometrical Model (IGM) for the generic solution of the trunk was established and its adaptation to our particular case was identified. An optimized solution for this mechanism based on 2 various criteria was then given.
... For example, pneumatics [1] [2]or hydraulics [3]∼ [6] was used to satisfy the maximum torque. Meanwhile, although the electric actuators is difficult to achieve high torque, the electric actuators [7]∼ [14] was widely developed because of the excellent control and low-cost. However, the torque required in some locations is less than the maximum torque. ...
... Some robots utilizing these actuator types include Asimo of Honda, HRP2,3,4 of AIST [7], HUBO of KAIST [8], REEM-C of PAL Robotics, JOHNNIE and LOLA of Tech. Univ. of Munich [9], [10], CHIMP of CMU [11], Robosimian of NASA JPL [12], and more. These actuators have precise position control and high torque density. ...
... Some robots utilizing these actuator types include Asimo of Honda, HRP2,3,4 of AIST [17], HUBO of KAIST [18], REEM-C of PAL Robotics, JOHNNIE and LOLA of Tech. Univ. of Munich [19], [20], CHIMP of CMU [21], Robosimian of NASA JPL [22], and more. These actuators have precise position control and high torque density. ...
We design, build, and empirically test a robotic leg prototype using a new type of high performance device dubbed a viscoelastic liquid cooled actuator (VLCA). VLCAs excel in the following five critical axes of performance, which are essential for dynamic locomotion of legged systems: energy efficiency, torque density, mechanical robustness, position and force controllability. We first study the design objectives and choices of the VLCA to enhance the performance on the needed criteria. We follow by an investigation on viscoelastic materials in terms of their damping, viscous and hysteresis properties as well as parameters related to the long-term performance. As part of the actuator design, we configure a disturbance observer to provide high-fidelity force control to enable a wide range of impedance control capabilities. After designing the VLCA, we proceed to design a robotic system capable to lift payloads of 32.5 kg, which is three times larger than its own weight. In addition, we experiment with Cartesian trajectory control up to 2 Hz with a vertical range of motion of 32 cm while carrying a payload of 10 kg. Finally, we perform experiments on impedance control by studying the response of the leg testbed to hammering impacts and external force interactions.
... Advances in DC motor, SEA, and hydraulic servo valve designs have also pushed the envelope in the performance capabilities of bipedal and humanoid machines. Taking insights from the design of JOHNNIE (Gienger et al., 2001), researchers at the Technical University of Munich designed the 25 DoF humanoid LOLA (Lohmeier et al., 2006) to study fast human-like walking. LOLA (Figure 1.11) is 180 cm tall and weights approximately 55 kg. ...
Animals exhibit remarkable locomotion capabilities across land, sea, and air in every corner of the world. On land, legged morphologies have evolved to manifest magnificent mobility over a wide range of surfaces. From the ability to use footholds for navigating a challenging mountain pass, to the capacity for running on a sandy beach, the adaptability afforded through legs motivates their prominence as the biologically preferred method of ground transportation. Inspired by these achievements in nature, robotics engineers have strived for decades to achieve similar dynamic locomotion capabilities in legged machines. Learning from animals’ compliant structures and ways of utilizing them, engineers developed numerous novel mechanisms that al- low for more dynamic, more efficient legged systems. These newly emerging robotic systems possess distinguishing mechanical characteristics in contrast to manufacturing robots in factories and pave the way for a new era of mo- bile robots to serve our society. Realizing the full capabilities of these new legged robots is a multi-factorial research problem, requiring coordinated ad- vances in design, control, perception, state estimation, navigation and other areas. This review article concentrates particularly on the mechanical design of legged robots, with the aim to inform both future advances in novel mech- anisms as well as the coupled problems described above. Essential techno- logical components considered in mechanical design are discussed through historical review. Emerging design paradigms are then presented, followed by perspectives on their future applications.
... Shotaro Mamiya et al. have proposed a foot structure with point contact links to adapt to the ground surface with various geometry and hardness [8]. Sebastian Lohmeier et al. have designed a humanoid robot LOLA with actively driven toe joints [9]. Kenji Hashimoto et al. have developed a human-like foot mechanism mimicking the medial longitudinal arch to clarify the function of the foot arch structure [10]. ...
This paper is a presentation of a work that consists of considering a novel foot structure for biped robot inspired by human foot. The specific objective is to develop a foot mechanism with human-like toes for a small biped robot. The chosen architecture to present the biped includes ten degrees of freedom (DoF) on ten articulations between eleven links. Our study considers the effect of varying foot structure on a walking process of the robot in simulation by ADAMS (MSC software, USA) through gait generation method. In toe mechanism, aiming to reduce the energy consumption, the passive joint was selected as the toe joint. The center of gravity (CoG) point trajectories of the robot with varying toe is compared with each other in normal motion on flat terrain to determine the most consistent toe mechanism. The result shows that the selected foot structure enables the robot to walk stably and naturally.
... Similarly KAIST built KHR-1/2/3 (Hubo) (Park et al., 2007) and Waseda continued its long and successful tradition to build many different models through to Wabian-2R (Ogura et al., 2006). The iCub humanoid represents a co-ordinated European effort in the humanoid arena aiming at producing a "child-like" humanoid platform for understanding and development of cognitive systems (Metta et al., 2005;Tsagarakis et al., 2007;Tsagarakis et al., 2011), but other successful humanoid/bipedal implementations within Europe include the humanoid LOLA which is an enhancement over the Johnnie robot (Lohmeier et al., 2006) and the recently developed torque controlled humanoid TORO (Englsberger et al., 2014). ...
In this work, we present WALK-MAN, a humanoid platform that has been developed to operate in realistic unstructured environment, and demonstrate new skills including powerful manipulation, robust balanced locomotion, high-strength capabilities, and physical sturdiness. To enable these capabilities, WALK-MAN design and actuation are based on the most recent advancements of series elastic actuator drives with unique performance features that differentiate the robot from previous state-of-the-art compliant actuated robots. Physical interaction performance is benefited by both active and passive adaptation, thanks to WALK-MAN actuation that combines customized high-performance modules with tuned torque/velocity curves and transmission elasticity for high-speed adaptation response and motion reactions to disturbances. WALK-MAN design also includes innovative design optimization features that consider the selection of kinematic structure and the placement of the actuators with the body structure to maximize the robot performance. Physical robustness is ensured with the integration of elastic transmission, proprioceptive sensing, and control. The WALK-MAN hardware was designed and built in 11 months, and the prototype of the robot was ready four months before DARPA Robotics Challenge (DRC) Finals. The motion generation of WALK-MAN is based on the unified motion-generation framework of whole-body locomotion and manipulation (termed loco-manipulation). WALK-MAN is able to execute simple loco-manipulation behaviors synthesized by combining different primitives defining the behavior of the center of gravity, the motion of the hands, legs, and head, the body attitude and posture, and the constrained body parts such as joint limits and contacts. The motion-generation framework including the specific motion modules and software architecture is discussed in detail. A rich perception system allows the robot to perceive and generate 3D representations of the environment as well as detect contacts and sense physical interaction force and moments. The operator station that pilots use to control the robot provides a rich pilot interface with different control modes and a number of teleoperated or semiautonomous command features. The capability of the robot and the performance of the individual motion control and perception modules were validated during the DRC in which the robot was able to demonstrate exceptional physical resilience and execute some of the tasks during the competition.
For patients with lower limb dysfunction who need to complete gait rehabilitation training, a new single-degree-of-freedom human lower limb rehabilitation training robot was designed, and a mechanism dimensional synthesis method was proposed. In order to realize the motion trajectory of the foot, a single-degree-of-freedom planar four-bar mechanism is selected as the mechanism unit, and the functional relationship between the input and output of the planar four-bar mechanism is analyzed and established, and a double four-bar synchronous motion mechanism is used to realize the relative motion of the heel and toe joint. Then, a Watt II six-link mechanism and a deflation mechanism are used to realize the motion trajectory of the toes. By acquiring the human gait trajectory through the Xsens MVN Analyze, thus giving the rigid-body line of desired according to the motion trajectory. The desired rigid-body line is processed by the non-equal interval normalization method, and the mechanism is designed by the numerical atlas method and the approximate synthesis method. The results show that the designed single-degree-of-freedom mechanism can simulate the motion of normal human gait motion trajectory, and the effectiveness of the design method is verified by experiments.
The gearbox of the small joint steering gear of a service robot is characterized by a compact structure, a large reduction ratio, and a special manufacturing and assembling technology. However, when a tooth in the gear is broken, the gear transmission can be still maintained, so it is difficult to identify the broken tooth accurately. In order to provide a theoretical basis for the identification of a broken tooth in the study, the influence of gear tooth fracture on the time-varying meshing stiffness in the transmission process was firstly analyzed theoretically and its influencing mechanisms on the time domain and frequency domain characteristics of transmission error (TE) were further analyzed. Then, the TE measurement test bench of the joint steering gear was designed. The signal-to-noise ratios and root-mean-square errors of the TE data processed by wavelet noise reduction, Kalman filtering and combined wavelet-Kalman filtering algorithms were compared and analyzed. The analysis results showed that the joint algorithm had the best performance. Next, the TE data measured under multiple working conditions were processed with the joint filtering algorithm to obtain the time domain results and then the frequency domain results were obtained by Fourier transform. Whether there was a broken tooth in the joint steering gear could be judged based on the difference between the maximum and minimum values of the TE in the time domain. The broken-tooth gear shaft could be positioned based on the frequency of TE mutation waveform. Furthermore, combined with the frequency domain, the accurate identification of the position of the broken gear can be realized. Finally, the accurate positioning method of broken teeth was applied in the product inspection process. Broken teeth were successfully identified and located, thus proving the effectiveness of the identification method.
This paper designs a hydraulic humanoid biped robot with 12 degrees of freedom named Defensor. First of all, this paper chooses the self-designed hydraulic humanoid biped robot as the research object. Then the Defensor’s structural design is introduced includes sensors distribution and Defensor’s 12-DOF on the structure. Secondly, a linear inverted pendulum model is established to simplify the Defensor’s whole model, and a hierarchical control structure is designed to control the movement of Defensor. Thirdly, this paper builds the virtual simulation platform Simscape Multibody and the experiment platform of Defensor. After that, the gait planning of the robot is realized, and the relevant research results are verified. Lastly, this paper realizes the Defensor’s continuous and stable walking in the virtual simulation platform. The simulation results show that Defensor’s mechanical model is reasonable and the gait planning control method adopted in this paper makes the hydraulic humanoid biped robot stable and feasible.
One type of robot is a robot with legs that can freely move in all directions and fields representing a human-like form. In a robot movement system, stability and balance present fundamental problems that often arise decreasing the robot's performance especially in robots utilizing feet as a moving medium. The number of legs dramatically affects the balance of the robot. Smaller number of legs generates smaller stability and balance, leading to more significant flexibility. Therefore, this research aims to highlight the stability and balancing, recently alleged as an important topic. The results of this study are in the form of algorithms or methods which create the robot movement in a balanced manner preventing from effortless fall, performed through Zero Moment Point or ZMP. In this study, the authors analyzed the balance of a humanoid robot by paying attention to the robot's Zero Moment Point using Fuzzy. When the robot is walking in place, the robot is not moving or when the robot is walking. This humanoid robot has two legs -called bipedal, demonstrating a lower balance level than other legged robots. It is thus possible to analyze and conduct further development in the present and future, by using the ZMP, anticipated that robot can move without slipping of more than 1 meter
Single degree-of-freedom (DOF) planar linkage mechanism has been widely used in bio-inspired robots because of its simple control. However, designing a single DOF mechanism to meet the complex motion law of creatures is difficult, and the multiple variables of six- or eight-bar mechanism further increase the design difficulty. A design method of single DOF planar linkage bionic mechanism is proposed in this paper. Through the continuous constraints on the position of all reference points with constraint descent method, the requirements of the bionic mechanism in shape, motion trajectory, and posture are met. As for the mechanism by which reference point coordinates cannot be expressed as the analytical solution of the driving angle, a single DOF mechanism is equivalent to a double DOF mechanism containing additional optimization variables, which further improves the design efficiency. For example, the design process of six- and eight-bar bionic mechanisms is given, confirming the feasibility of the method. Then, the effects of the constraint conditions on the design process are analyzed in detail. This study provides a reference for the design of bio-inspired robots.
This paper proposes a powered ankle-foot prosthesis called PANTOE II, which includes an ankle and a segmented foot with a toe joint. The ankle and toe joints are both driven by series elastic actuators, which can reduce the required velocity and energy consumption of the actuators. The mechanical design of the ankle and toe joints makes the prosthesis more compact. In addition, PANTOE II employs a more human-like foot, which includes the heel, the mid foot, and the toe. Both the heel and the toe are made of leaf springs, and the mid foot is used to install the transmission mechanisms. The finite state control strategy is used for controlling the prosthesis. To evaluate the basic performance of PANTOE II, experiments are conducted on a subject with a transtibial amputation. Wearing PANTOE II, the amputee feels more comfortable and presents more symmetrical walking gaits.
As small-sized absolute encoders are currently being installed in small and high-power motors, a dual absolute encoder (DAE) system comprising two absolute encoders can now be constructed. The two absolute encoders in the DAE system are installed on a motor shaft and an output shaft; further, the two shafts are connected by a reduction mechanism. The DAE system will replace an ordinary dual encoder system in the future, because of its high accuracy and extended measurement range. In this paper, an analysis of the accuracy and measuring range of DAE system is presented. Index numbers that are calculated from readings of absolute encoders have a one-to-one correspondence with the number of rotations of the two shafts. Their positions are calculated based on the index number and extended greatest common factor (
EGCF
) of 1 and the inverse of reduction ratio. The error in the index number is investigated and maximum error tolerance of an absolute encoder that guarantees correct position estimation is proposed. Experiments are conducted separately in narrow and wide measurement ranges. Each range exhibits different types of errors, small random and large periodic errors. The large periodic errors are compensated using harmonic function model. The small random errors are utilized to calculate the maximum error tolerance and minimum resolution of the absolute encoder at the output shaft. The experimental results demonstrate that the final error decreases and the measurement range is extended to 1/
EGCF
in the DAE system compared with the ordinary dual encoder system.
This article focuses on the design and integration of a parallel modular mechanism inside the waist of a human-sized biped robot to enable tilting motion of the torso. The mechanism for each tier is adapted from the parallel 2-degree-of-freedom tilting part of an existing 3-rotation flight simulator structure. The main contribution of this work is the design of a minimized-torque-oriented optimization process that takes into account the upper mass load to be supported by the mechanism, the constrained volume of the waist, a minimal dexterity threshold, and the tilting range required. The design process aims to determine the relative size and position of the different parts of the mechanism. The objective consists of minimizing the actuator average torque over the entire tilt range, and to evaluate how much torque reduction this parallel mechanism can bring compared with the use of a serial mechanism. Up to three modules can be stacked inside the waist to limit the actuator torques and to reach the required tilting range for sitting and bending movements.
This paper is an overview of the humanoid robot Rh-1, the second phase of the Rh project, which was launched by the Robotics Lab at the Carlos III University of Madrid in 2002. The robot mechanical design includes the specifications development in order to construct a platform, which is capable of stable biped walking. At first, the robots’ weights were calculated in order to obtain the inverse dynamics and to select the actuators. After that, mechanical specifications were introduced in order to verify the robot’s structural behaviour with different experimental gaits. In addition, an important aspect is the joints design when their axes are crossed, which is called ‘Joints of Rectangular Axes’ (JRA). The problem with these joints is obtaining two or more degrees of freedom (DOF) in small space. The construction of a humanoid robot also includes the design of hardware and software architectures. The main advantage of the proposed hardware and software architectures is the use of standardised solutions frequently used in the automation industry and commercially available hardware components. It provides scalability, modularity and application of standardised interfaces and brings the design of the complex control system of the humanoid robot out of a closed laboratory to industry. Stable walking is the most essential ability for the humanoid robot. The three dimensional Linear Inverted Pendulum Model (3D-LIPM) and the Cart-table models had been used in order to achieve natural and dynamic biped walking. Humanoid dynamics is widely simplified by concentrating its mass in the centre of gravity (COG) and moving it following the natural inverted pendulum laws (3D-LIPM) or by controlling the cart motion (Cart-table model). An offline-calculated motion pattern does not guarantee the walking stability of the humanoid robot. Control architecture for the dynamic humanoid robot walking was developed, which is able to make online modifications of the motion patterns in order to adjust it to the continuously changing environment. Experimental results concerning biped locomotion of the Rh-1 humanoid robot are presented and discussed.
A model-free robust adaptive controller is proposed for control of humanoid robots with flexible joints. The proposed controller uses a time-delay estimation technique to estimate and cancel nonlinear terms in robot dynamics including disturbance torques due to the joint flexibility, and assigns desired dynamics specified by a sliding variable. A gain-adaptation law is developed to dynamically update the gain of the proposed controller using the magnitude of the sliding variable and the gain itself. The gain-adaptation law uses a leakage term to prevent overestimation of the gain value, and offers stable and chattering-free control action. The effectiveness of the proposed adaptive controller is experimentally verified on a humanoid robot equipped with flexible joints. Tracking performances of the auto-tuned adaptive gain are better than those of the manually-tuned constant gains. The proposed control algorithm is model-free, adaptive, robust and highly accurate.
In this paper, we describe the mechanical design, system integration and dynamic walking of the humanoid, KHR-2 (KAIST Humanoid Robot– 2). KHR-2 has 41 DOFs in total, that allows it to imitate various human-like motions. To control all joint axes effectively, the distributed control architecture is used, which reduces computation burden on the main controller, and allows convenient system. A servo motor controller was used as the sub-controller, whereas a 3-axis force/torque sensor and an inertia sensor were used in the sensory system. The main controller attached on the back of KHR-2 communicates with the sub-controllers in real-time through CAN (Controller Area Network) protocol. Windows XP was used as the operation system, whereas RTX HAL extension commercial software was used to realize the real-time control capability in Windows environment. We define the walking pattern and describe several online controllers in each stage. Some of the experimental results of KHR-2 are also presented.
Deals with the design and control of an anthropomorphic autonomous biped robot. The objective is to realize a dynamically stable, three-dimensional walking and jogging motion. The design, sensors and electronics of the robot are introduced. Particular emphasis has been devoted to achieving a high power-to-weight ratio. The corresponding methods for weight reduction are presented. The control scheme is discussed. It is based on the method of feedback linearization employing the equations of motion of the system.
Addresses the extension of a humanoid's action capability by
attaching toe joints. The effectiveness of toe joints is discussed in
three aspects. One is utilizing it to speed up the walking, another is
using it to enable a humanoid to go up higher steps, and the other is
using it to whole-body action in which knees are contacting the ground.
Feet with toe joints are developed for humanoid 'H6'. An experiment of
the wholebody action in which knees are contacting the ground is carried
out to show the usefulness of toe joints for such actions. Then the
walking pattern generation system is extended to use toe joints. Using
this extended system maximum speed of knee joints can be reduced at the
same walking speed, and 80% faster walking speed is achieved on humanoid
'H6'
Dynamics simulation is a valuable tool for biped robot hardware and controller design. Due to the complexity of biped walking robots, simulation times can be quite high. It is therefore important to identify the key components in modeling the system so that the phenomena of interest can be correctly predicted at a reasonable numerical cost. In this paper a detailed and a reduced simulation of the biped robot JOHNNIE are presented and results are compared with experimental data. The comparison shows that results for both models correctly predict global dynamics of the system, while some phenomena are only captured by the more complex model
Almost all conventional biped humanoid robots have difficulties in realizing various walking motions such as knee stretch walking like a human because of an insufficiency of DOF. Therefore, we have developed a 16-DOF biped humanoid robot without a trunk: 3-DOF in each ankle, 1-DOF in each knee, 3-DOF in each hip and 2-DOF in the waist. Using the biped robot, basic experiments are conducted and the effectiveness of the leg mechanism is confirmed.
The biped robot "Johnnie" is designed to achieve a dynamically stable gait pattern, allowing for high walking velocities. Very accurate and fast sensors were developed for the machine. In particular the design of the 3D-orientation sensor and the 6-axes force-torque sensor are presented. The control scheme is based on the information from these sensors to deal with unstructured terrain and disturbances. Two different implementations are investigated: a computed torque approach and a trajectory control with adaptive trajectories. Walking speeds of 2.2 km/h have been achieved in experiments.
This paper addresses the problem of gait pattern generation for biped robots. A method based on nonlinear parameter optimization is proposed. Key features of the method are the trajectory description, optimization of only a subset of coordinates and the use of analytical, recursively calculated gradients for cost functions and constraints. The method has been used successfully to calculate walking trajectories for the 3D 17-DOF robot "Johnnie"
A development of humanoid robot HRP-2 is presented in this paper. HRP-2 is a humanoid robotics platform, which we developed in phase two of HRP. HRP was a humanoid robotics project, which had run by the Ministry of Economy, Trade and Industry (METI) of Japan from 1998FY to 2002FY for five years. The ability of the biped locomotion of HRP-2 is improved so that HRP-2 can cope with uneven surface, can walk at two third level of human speed, and can walk on a narrow path. The ability of whole body motion of HRP-2 is also improved so that HRP-2 can get up by a humanoid robot's own self if HRP-2 tips over safely. In this paper, the appearance design, the mechanisms, the electrical systems, specifications, and features upgraded from its prototype are also introduced.
Aiming for a humanoid robot of the next generation, we have been developing a biped which can jump and run. This paper introduces biped robot HRP-2LR and its hopping with both legs as our first attempt towards running. Using a dynamic model of HRP-2LR, hopping patterns are pre-calculated so that it follows the desired profiles of the total linear and angular momentum. For this purpose we used resolved momentum control. Adding small modifications to negotiate the difference between the model and the real hardware, we successfully realized a steady hopping motion of 0.06 [s] flight phase and 0.5 [s] support phase. A hopping with forward velocity of 15 [mm/s] was also realized. Finally, a running pattern of 0.06 [s] flight and 03 [s] support phase was tested. HRP-2LR could successfully run with average speed of 0.16 [m/s].
SDR-4X is the latest prototype model, which is a small humanoid type robot. We reported the outline of this robot last year. In this paper we discuss more about mechanical system, which is important and original for a small biped entertainment robot, which will be used, in home environment. One technology is the design of actuators alignment in the body, which enables dynamic motion performance. Another technology is the actuator technology, which we originally developed, named intelligent servo actuator (ISA). We explain the specification and the important technical points. Next technology is the sensor system, which supports the high performance of the robot, especially the detection of outside objects, ability of stable walking motion and safe interaction with human. The robot is used in normal home environment, so we should strongly consider the falling-over of the robot. We propose the ideas against falling-over which makes the robot as safe as possible.
A third generation of torque-controlled light weight robots has been developed in DLR's robotics and mechatronics lab which is based on all the experiences that have been had with the first two generations. It aims at reaching the limits of what seems achievable with present day technologies not only with respect to light-weight, but also with respect to minimal power consumption and losses. One of the main gaps we tried to close in version III was the development of a new, robot-dedicated high energy motor designed with the best available techniques of concurrent engineering, and the renewed efforts to save weight in the links by using ultralight carbon fibres.
This paper presents the final stage of development of the humanoid
system, ETL-Humanoid. It is full-scale humanoid system with 46 degrees
of freedom, with the height and weight of an average Japanese person. It
was designed as an experimental platform, to explore the general
principle of controls of complex embodied systems. The complete system
will be presented; the mechanical configuration of the system and the
low-level network-based control system will also be presented. The final
system possesses properties of compactness, modularity and is light in
weight. The mechanical system is high in performance, is backdrivable
and compliant, allowing the possibility of a wide range of motions and
capabilities. The general capability of being able to support itself is
demonstrated. A "Chin Up" experiment showing the physical strength of
our system is presented. The system is able to support its own body
weight while rising up to a supporting bar. Aside from its physical
strength, the system is also capable of performing higher-level
perceptions and actions. These capabilities will be briefly presented
This paper describes the progress of the BIP2000 project. This
project is aimed at the realization of the lower part of an
anthropomorphic biped robot. The robot consists of two legs, two feet, a
pelvis and a trunk. It has 15 active joints. The mass distribution, the
kinematics and the capacities of the robot in terms of joint torques are
close to the ones of humans. The transmissions are specific
screw/nut-based systems which have good dynamic performances and small
size. They are arranged in parallel at the ankles and at the
trunk/pelvis linkage. The control schemes are either based on a control
of the center of mass associated with suitable task functions, or take
dynamically into account the unilateral constraints foot/ground. The
robot has been built and tested, the computer control architecture has
been realized and connected with the robot, and the basic control
schemes have been implemented
In this paper, we present the mechanism, system configuration,
In this paper, we present the mechanism, system configuration,
basic control algorithm and integrated functions of the Honda humanoidbasic control algorithm and integrated functions of the Honda humanoid
robot. Like its human counterpart, this robot has the ability to moverobot. Like its human counterpart, this robot has the ability to move
forward and backward, sideways to the right or the left, as well asforward and backward, sideways to the right or the left, as well as
diagonally. In addition, the robot can turn in any direction, walk updiagonally. In addition, the robot can turn in any direction, walk up
and down stairs continuously. Furthermore, due to its unique postureand down stairs continuously. Furthermore, due to its unique posture
stability control, the robot is able to maintain its balance despitestability control, the robot is able to maintain its balance despite
unexpected complications such as uneven ground surfaces. As a part ofunexpected complications such as uneven ground surfaces. As a part of
its integrated functions, this robot is able to move on a planned pathits integrated functions, this robot is able to move on a planned path
autonomously and to perform simple operations via wireless teleoperationautonomously and to perform simple operations via wireless teleoperation
The purpose of this paper is to develop systematic analysis and
design methods for a two-inertia system. A conventional
proportional-integral speed control system with a torsional load is
redesigned, and the damping characteristic of the system is derived and
analyzed. It is shown that the dynamic characteristic of the system
strongly depends on the inertia ratio of load to motor. Three kinds of
typical pole assignments with identical radius/damping coefficient/real
part are applied and compared, and the merits of each pole-assignment
design are concluded. Furthermore, for small inertia ratio, we present
how to improve the damping of the system by a derivative feedback of
motor speed
Dec) New ASIMO -running at 6km/h
- Co Ltd
Honda Motor Co., Ltd. (2005, Dec) New ASIMO -running at 6km/h. [Online]. Available: http://world.honda.com/HDTV/ASIMO/ New-ASIMO-run-6kmh/
Entwurf und Realisierung einer zweibeinigen Laufmaschine, ser. Fortschrittberichte VDI, Reihe 1. D ¨ usseldorf
- M Gienger
M. Gienger, Entwurf und Realisierung einer zweibeinigen Laufmaschine, ser. Fortschrittberichte VDI, Reihe 1. D ¨ usseldorf: VDI-Verlag, 2005, no. Nr. 378.
Dec) New ASIMO - running at 6km/h. [Online] Available: http://world.honda.com
- Honda Motor Co
- Ltd