Yusuke Sugahara

Tokyo Institute of Technology | TITech · Department of Mechanical Engineering

The authors develop the mobile robots traversing on spatially structured cableway. In previous research, a depth camera was used to estimate the start timing of the front wheel's motion to pass cable node, but it could not be used for the rear wheels. In reality, there is slippage between the wheels and the rope, so that of the rear wheel’s motion...

An actuator, called RHA (Redundant Hybrid Actuator), composed of two types of motors connected in series which can mechanically switch its operation modes between a large torque mode and a small torque mode is proposed to achieve Assist-As-Needed actuation for assistive devices. A model which was supposed to apply the actuator to an assistive devic...

The Authors study on cable traversing robot on spatially-structured cableway. The robot has a problem of low weather resistance. Therefore, the purpose of this research is to improve weather resistance of cable traversing robot by making it waterproof. For waterproofing, the motors, PC, and camera must be protected from water. The waterproofing tar...

The decline in muscle strength and physical fitness that accompanies aging makes it difficult for the elderly to maintain independence in daily living, and they require assistance from others. Many assistive devices for Sit-to-Stand have been developed, but it is also important to work on maintaining and improving muscle strength and physical fitne...

The non-linearity of Shape Memory Alloy's (SMA) input vs. output relationship has been a significant barrier to their broader application for actuators. In this article, we introduce a novel activation approach with the objective of improving the output nonlinearity in SMA actuators by using a liquid temperature gradient for activation. This gradie...

Shape Memory Alloy (SMA) actuators have output non-linearities, posing challenges for control in robotic applications. As an alternative to model- and controller-based compensation, in this paper, with the objective of enhancing the linearity of the SMA output to make it possible to use conventional control algorithms, we present a novel physical c...

Parallel Continuum Robot, preserves the characteristics of flexibility, safety and agility due to its continuous structural nature. Additionally, the parallel configuration provides enhanced precision and stiffness, making it an increasingly attractive option for applications in confined space operation and human-contact scenarios such as human col...

A novel wearable end-effector type upper limb assistive robot for stroke hemiplegic patients is proposed, and a 3 DOF 4R-5R parallel mechanism for this type of robots is presented. Assistive functions of the robot are finalized to motion and force assistance to allow patients to have their paralyzed limb perform auxiliary roles in ADL. Kinematics o...

The development of independent link type gait assistive device is explaining in this work. Independent link type gait assistive deviceis targeted the person with muscle weakness and restriction in ankle dorsiflexion range of motion (ROM). This device helps the user to walk within their ankle dorsiflexion ROM while maintaining other walking posture...

This study presents a concept of a collaborative robot consisting of a cable-suspended parallel mechanism and a vertical downward thruster equipped on its end-effector to achieve low risk in the event of collision, and good positioning performance at high speed operation. A prototype of a 4-wires 2 degrees-of-freedom vertical planar translational c...

To promote good health and well-being is one of the Sustainable Development Goals (SDGs) drawn by the United Nations. To this end, the development of assistive devices is important to improve the quality of life for both caregivers and patients. This study aims to provide support in transfer assist, which is known to be strenuous work in the care e...

With the increasing number individuals living with the long-term effects of stroke, it has become more important to provide accessible healthcare, in line with the UN SDG 3 on promoting good health and well-being. Hemiplegia, the paralysis of one side of the body, is a common side effect of stroke. The condition of hemiplegia provides unique challe...

In order to make assist devices light, compact and easy to customize, we proposed to apply redundant motors (RMs). RM consists of many small motors with reduction gears in parallel instead of one large geared motor. Thanks to the composition of RM, compact design will be enabled by arranging many small motors with in the allowable space, and its ma...

In order to develop a cable-driven continuum robot having a large workspace without using a large number of segments, which leads to construction complexity and requires the use of many actuators, this paper presents a mechanism design for increasing the orientation workspace volume of a one-segment continuum robot by realizing multiple elastic rod...

In order to make assist devices light weight, compact, and easy to customize, use of a redundant motor actuator (RM) is considered effective. RM consists of many small motors with reduction gears in parallel instead of one large motor with reduction gears. Mass of gears in RM can be reduced by distributing the load torque to multiple working teeth...

Engineering researchers perform an essential role in developing assistive technology that increases, maintains, and improves the functional capabilities of individuals with disabilities/difficulties in their daily lives. The researchers have employed human-centric design (HCD) to meet diverse special needs. However, an increasingly turbulent enviro...

Tendon-driven Continuum Manipulator (TCM) is a kind of flexible manipulator with outstanding performance on dexterity, safety and intrinsic force sensing ability. These features make TCM prospective for the application in human contact scenarios such as Robot-assisted Minimally Invasive Surgery (RMIS). As an improvable point, this paper proposed a...

In an earthquake simulator, which is a device for reproducing seismic waves, it is necessary to accurately reproduce the acceleration. In this letter, the authors propose an offline reference trajectory shaping method for precise acceleration control based on the dynamic model of an earthquake simulator, composed of a planar three-degrees-of-freedo...

Robots have generally many degrees of freedom and require many actuators to actuate. Designers have often wondered if it would be possible to assign actuators not to each joint but for each desired motion appropriately, and in such cases, the differential mechanism has attracted attention. Furthermore, environmental adaptability can also be achieve...

Scalability of actuators is the ability to change their output characteristics on demand. In a previous research, we proposed a Wet-activated Shape Memory Alloy (SMA) wire-bundle linear actuator that can scale its maximum output force in an easy manner. However, it was determined that the bundling technique we used produces a nonuniform stress dist...

An independent arm type assist device is proposed to provide assistance to the ankle joint plantar flexion torque while being driven independently of the ankle joint motion. A structure of the device was proposed and the required specifications were determined using walking data. Based on these specifications, a redundant motor actuator for this as...

This paper describes the kinematics, motion planning and mechanism optimization of the dual-arm type cable traversing robot on spatially-structured cable way. Since the inverse kinematics cannot be perfectly defined due to one of the orientation parameters is determined by static condition, its inverse kinematics algorithm utilizing both the kinema...

In this paper, the concept of scalability for actuators is introduced and explored, which is the capability to freely change the output characteristics on demand: displacement and force for a linear actuator, angular position and torque for a rotational actuator. This change can either be used to obtain power improvement (with a constant scale fact...

This paper presents the basic performance evaluation of a design concept for linear scalable Shape Memory Alloy (SMA) wire actuators controlled by the temperature of a liquid. Fluid heat transmission with SMA wires, contrasting with Joule heating, allows the design to provide scalability of its maximum output force and displacement by changing the...

As a device for pasting film objects on curved surfaces, this paper proposed a device, composed of a shape adaptable mechanism and an elastic electrostatic chuck, which is operated by two robot arms. As the shape adaptable mechanism generating a wide range of variable curvature radii, a single-DOF scissor mechanism with an elastic element was prese...

The water jet impact acoustic method is the wall inspection method to detect the concrete flaking by analyzing the sound generated by the water hit on the structure. The authors are developing the completely constrained planar CDPR (cable-driven parallel robot) to move and position the device for this method facing the wall. In general, the planar...

Mobility device is important for the people with disabilities. In the previous research, we developed a hands-free mobility, a nonholonomic mobility, which included the operation system using interactive learning system between human and robot, and found that when discussing interactive learning system between human and robot, we need to consider t...

In this research, a concept of robotic wheelchair which automatically follows a human caregiver side by side is proposed. This concept is aiming to promote the communication between a wheelchair rider and his/her caregiver since they can talk face-to-face while advancing forward. This research focuses on a derivation of a motion control law to achi...

A new generation electric high-speed train called Aerotrain has levitation wings and levitates under Wing-in-Ground (WIG) effect along a U-shaped guideway. The previous study found that lacking knowledge of the design makes the prototype unable to regain stability when losing control. In this paper, the nonlinear three-dimensional dynamic model of...

In order to realize a high speed and high space use efficiency transportation system in a vertical plane, authors conceived a concept to compose the system by multiple vertical rails and multiple self-propelled loading platforms so that such platforms can independently move along each rail and transfer between them. This paper focuses on the design...

When a deployable origami structure is kinematically modelled as a link mechanism by replacing the creases by revolute joints, the obtained mechanism is generally overconstrained. In practice, devices and machines originated from overconstrained mechanisms need in-situ adjustments for assembly, and even encounter difficulty in assembly since they a...

We developed a small robot with Inline Archimedean Screw Mechanism in response to the demands of surveying Invasive Alien Species (IAS). There are some harmful IAS in wetlands such as snapping turtles. The current method for the survey is net-trap (“Mondori-wana”) and fumbling search by humans. Both methods are inefficient and unsafe for humans. To...

This paper describes the development of the suspended cable-driven parallel robot for object transportation having power assist function. The robot consists of the winches to drive four cables which suspend the object and control its three degrees of freedom motion. The impedance controller based on the external force measured by the tension sensor...

Our research aims at developing a meal-assistance robot with vision system and multi-gripper that enables frail elderly to live more independently. This paper presents a development of a chopstick-type gripper for a meal-assistance robot, which is capable of adapting its shape and contact force with the target food according to the size and the sti...

On the Moon, several deep pits that probably associates with large igneous caves like lava tubes have been found. The lunar pits and caves are significant for lunar science and as candidates for lunar bases. In this trend, we are investigating a small robot system WAseda PIt exploring roboT (WAPIT) to explore the lunar pits. WAPIT has two wheels fo...

The Aerotrain is a new generation train that floats at a low altitude along a U-shaped (concrete) guideway by the aerodynamic forces generated at the two levitation wings. Using the wing-in-ground effect, the Aerotrain can have an advantage in reducing the operating cost through its low-cost guideway while maintaining high-speed under high-payload...

In this study, focusing on the sustainability of environment and health, it has proposed Man-powered mobility.The proposed system is designed on the“ Man-powered robotics”, which realizes the intelligent operation by controlling the power to be transmitted to the output shaft in the robot system. Man-power to implement the safety control in mobilit...

In conventional configuration of Parallel Cable Mechanism, anchors (winding machines) were fixed and practically used in structured environment. In an attempt to reduce the hurdle of the above application in an unstructured environment, a concept of spatially structured cableway with traversing mobile anchors on it is proposed in this paper. Techni...

As robots become more and more ubiquitous in human society, the study of their emergence becomes critical to assessing robot performance and appropriateness for different applications, and for employment across countries with different cultural backgrounds. Throughout history, religion has been a major element in all human cultures, and there is a...

In this paper, the modeling of a double helical compliant joint and its characterization are introduced. The Double Helical Compliant Joint (DHCJ) was designed to increase the workspace in a compliant mechanism. The joint consists of leaf springs that are symmetrically arranged between two helical frames. The modified-type DHCJ was created to show...

The Origami Spring is one of the convertible origamis and its macroscopic motion is often regarded as a single Degree-of-Freedom (DoF) motion while in theory, its DoF is three DoF mechanism. In this paper, a new displacement analysis was introduced to study the behavior of Origami Spring. The Origami Spring was modeled as a link mechanism which inc...

In order to reproduce seismic waves classified in long-period ground motion by disaster prevention education facility, an earthquake simulator based on a cable-driven parallel mechanism has been constructed. In this paper, a feedforward-based control scheme was implemented in the cable-driven earthquake simulator for achieving high acceleration wit...

Origami Spring is one of the extendable Origamis which changes from a flat to a tower configuration. The important feature of the Origami Spring is that its whole structure simultaneously extends/contracts with a slight bending as a parasitic motion of the extension/contraction when only one of the segments is actuated. Therefore, such an observed...

This paper proposes a new shape memory alloy (SMA)-driven compliant rotary actuator that can perform both passive and self-actuated motions. This SMA actuator is suitable as a redundant actuation part in a parallel robot joint to assist with singularity postures where the robot might lose the ability to maintain the position and orientation of the...

This study proposes “Human-Powered Robotics,” a concept of the intelligent machines driven by the power applied by user directly. The development of the robotic personal mobility vehicle prototype based on this concept is described in this paper. This is a vehicle driven by the operator’s pedaling power, which is capable of servo control of the whe...

Evaluating parallel robots’ performance is a key to achieve a better design and better understanding of their behavior in operation. In this study, a novel idea of local performance evaluation of robots taking into consideration the directional variation of performance was proposed by introducing a circular trajectory around a local output point. T...

This paper proposed the new SMA driven compliant rotary actuator, which is able to perform both passive and self-actuated motions. This kind of actuator can be used as redundant actuation part in parallel robot’s joint to help for the singularity postures that the robot might lose the ability to maintain the position and orientation of the end effe...

This paper proposed a chopstick-type gripper for a meal-assistance robot, which is capable of adapting its shape and the contact force with the target food according to the size and the elasticity of the food. Solely using position control of the driving motor for the mechanism, this feature was enabled without relying on force sensors. The gripper...

In the present paper, a systematic method useful in the structural design and motion synthesis of motion assist exoskeleton. To this end, a method for analyzing complex human motions with multiple degrees of freedom for different functions and for regenerating arbitrary motions from the analyzed data by adjusting parameters based on the principal c...

In order to enable designing assistive devices/tools which are connected to some part of human body directly or through some attachment parts, such as wearable power-assist suits, joint rehabilitation devices and walking sticks, taking into consideration the deformation of the connection parts and slippage between them, the concept “dynamic pair” i...

In the present paper, the authors propose a reconfigurable multi robot system which consists of many robotic dolly units capable of transporting a heavy object in a group and a central unit for measuring the object's motion and distributing the acquired information to all dolly units. The system has no hierarchical control structure or supervising...

In this study, design and control theories for a suspended parallel wire system has been researched. Previously, theories are confirmed by a numerical formula and a simulation. In this paper, torque-adjusting high powered wire-reel robot, which employs commercially available electric reel as a reeling mechanism is proposed and described its perform...

In this paper, clanking effort reduction method for the single-DOF human-powered joint mechanism having regenerative servo clutches, by the power assist using regenerative energy and continuously variable transmission is proposed. Through the experiments, it was confirmed that the assist motor compensated external torque immediately and CVT reduced...

In this research, a new mobility vehicle for elderly is being developed, which combines lower limbs exercise effective for improvement of walking function, operation method enabling free upper limb movement, and movement support. This report summarizes the following three points; clarified target person and needs of movement activity, survey result...

In this study, focusing on a sustainability of an environment and user's health, an intelligent mobility system driving by a human power has been proposed. The proposed system was designed based on the Man-powered Robotics, which realizes a servo control on an output shaft/shafts by controlling transmitting power. Man-powered Robotics does not util...

This research focuses on developing a lower limb operated personal mobility vehicle for the elderly to provide transportation and to improve flail and sarcopenia. In this paper, the design of a pedal mechanism to apply an effective exercise load to the lower limbs is described. In order to realize an effective exercise load to improve the gait func...

In this study, focusing on a positioning of an object using a parallel-wire mechanism, some kind of model for a wire state estimation had been proposed. Previously, a mechanical wire-model based on the catenary curve, a way to judge that a wire is tensioned or not and a way to estimate wires, which will lose its tension were proposed in this study....

In this study, Man-powered Robotics has been proposed and some applications has been developed. Man-powered Robotics realizes servo control of axes using not electrical energy but human power inputted to the system using a handle, a pedal and so on. In this paper, to realize handling an object, a griping mechanism is proposed. The mechanism employs...

This paper proposed a chopstick-type gripper for a meal-assistance robot, which is capable of adapting its shape and the contact force with targets according to the size and the stiffness of the object. Solely using position control of the driving motor for the mechanism, this feature was enabled without relying on force sensors. The gripper was de...

Recently, facilities with the special intention to help people who lack walking ability or even sit in the wheel chair could be seen everywhere. However, in the hospitals, rehabilitation devices, which are used for people to regain their body functions right after some health problems, are very limited, and even the existing robots have not shown s...

In this study, focusing on a transportation of heavy small objects, a transportation system using a robotic mobility based on the Man-powered Robotics, is proposed. The Man-powered Robotics realizes intelligent operation by controlling power sources supplied by human pedaling. Therefore, a driver or an user just only input the power by pedaling, an...

The present paper discusses a systematic approach to figure out a practical and functional design of sextuple 3D-magnetic tweezer system to perform physical property measurement of biological cell specimens. The authors carried out static and dynamical analyses of the electromagnetic system by using a theoretical model described with closed-loop ma...

In the previous paper, taking the non-linear Wing-In-Ground effect into consideration, the longitudinal dynamic model of Aero-Train after expanding it with a horizontal tail was developed for the purpose to clarify the relationship between the body frame design and its stability. This paper describes the development of the longitudinal dynamic mode...

The present paper discusses an approach for quantitative evaluation of physical property of obstacles called “ease of movement” in order to make it possible disaster response manipulators to deal with harsh environment. The physical property evaluates how much force is necessary to make translation and rotation of target obstacle with respect to ea...

Wire-parallel mechanisms are categorized as two groups: fully constrained mechanisms and under-constrained mechanism. In this study, focusing on the under-constrained mechanism, a cable-suspended robot system have been developed. In such a mechanism, slacks of cables affects its design or control. In this paper, to improve them, slacks of cables ar...

In this study, focusing on the sustainability of the environment and health, it has proposed a mobility that human-powered. The proposed system is designed on the “Man-powered robotics”, which realizes the intelligent operation by controlling the power to be transmitted to the output shaft in the robot system. Manpower to implement the safety contr...

The goal of this study is to propose the concept “Human-powered robotics,” which is a methodology to design the robotic system which can control the joint by directly using a power applied by the operator. This paper illustrates the proposal of the driving assist method not to lose safety using regenerative energy on 1-DOF human-powered joint contr...

In order to improve living space for stable walks by elderly people, this paper discussed assessment of living space with unique-shaped support objects. Four evaluation indices expressing capability of balance recovery corresponding to the support object were derived based on directionality of generative force by human's upper extremity and directi...

This paper presents a kinematic characterization of the Origami Spring, which can change its shape from a flat, contracted state to a solid, extended state. Through observation using a real model, the Origami Spring was modelled as a spherical 6R linkage with 3 degrees of freedom (DOF). To obtain a kinematic model, which enables kinematic design of...

A 3-DOF parallel mechanism as a compact foot drive mechanism for the gait rehabilitation of walking-disabled patients was developed. Based on the preprocessed walking data captured from healthy individuals, reference motion for the footplate was determined and used to calculate the speci cations of the footplate drive mechanism. The dimensional syn...

By Man-powered Robotics, a system controls motion intelligently using power served by a user. In previous works about man-machine cooperation, the user recognizes the environment and judges/decides motions of the machine, and the machine controls the motion based on local sensor-feedbacks. On the other hand, the system based on the man-powered robo...

In order to assess living space for assisting stable walks by elderly people, this paper proposed an evaluation index for single support object which is calculated from four fundamental measures expressing capability of balance recovery corresponding to the support object, derived from the directionality of generative force by human’s upper extremi...

The goal of this study is to propose a concept of "Man-powered robotics," a design methodology for an intelligent robotic system powered by human's motion. In the system, the servo control of robotic joints is performed by controlling transmitted torque of the power given by human's motion. In this paper, for the developed prototype of the human-po...

This paper describes the mechanical design of the small amphibious mobile robot for environmental monitoring. To realize the body having amphibious locomotion performance by simple mechanism and principle of operation and high stability on the water, we proposed the amphibious propulsion crawler, the waterproof driving mechanism using commercially...

We present the first developed prototype of the co-worker robot “PaDY” (i.e., in-time Parts/tools Delivery to You) for automotive assembly processes and demonstrate its ef-fectiveness in assembling vehicles. PaDY delivers the necessary part(s) and tool(s) for each task, to a worker during the assembly process, increasing efficiency, by reducing unn...

Earthquake simulation is helpful in order for society to experience real seismic waves in safe environment. Cable-driven parallel mechanisms have advantages over conventional serial and parallel mechanisms. Prototype simulator which covers 1 m stroke in each direction has been built. In this paper, conceptual design of an earthquake simulator using...

The objective of this study was to design a new model of wheel shape for increasing climbing ability of slopes and steps. We made a new model using a statics for calculating the ability easily and found that the arc-shaped notch type seems to be the best and implemented to our robot. In this paper, we introduce the detail of the proposed model and...