Power assist method for HAL-3 using EMG-based feedback controller

When developing rehabilitation assist suits, safety consideration for patients is crucial. Computer-aided control techniques can improve their safety. However, when the computer breaks down, the assist suit may be dangerous for the user because of its unintentional motion. Therefore, assist suits with hardware-based safety devices are desired to guarantee safety even when the computers do not operate properly. In this paper, we present a new rehabilitation assist suit equipped with a velocity-based safety device and a torque limiter. The assist suit assists a patient's knee joint. The velocity-based safety device switches off the assist suit's motor if it detects an unexpected high joint angular velocity. The torque limiter cuts off the torque transmission if it detects an unexpected high joint torque. These safety devices will work even when the computer breaks down, because they consist of only passive mechanical components without actuators, controllers, or batteries. Firstly, we describe the features of the assist suit with the safety devices. Secondly, we introduce the structure of the assist suit. Thirdly, we explain the structure and mechanism of the velocity-based safety device. Fourthly, we show the prototype assist suit that we have developed. Finally, we present experimental results to verify the effectiveness of the velocity-based safety device installed on the developed assist suit. 3 Sugiyama, Ikeda, Kaneda, Kai and Tomizuka, Transactions of the JSME (in Japanese), Vol.83, No.856 (2017) Sugiyama, Ikeda, Kaneda, Kai and Tomizuka, Transactions of the JSME (in Japanese), Vol.83, No.856 (2017) 8 Sugiyama, Ikeda, Kaneda, Kai and Tomizuka, Transactions of the JSME (in Japanese), Vol.83, No.856 (2017) © 2017 Gear B were both measured by using a motion capture system (k7-USB, KATO KOUKEN Corporation) while increasing the motor velocity. Keywords 9Sugiyama, Ikeda, Kaneda, Kai and Tomizuka, Transactions of the JSME (in Japanese), Vol.83, No.856 (2017) © 2017 The time when the bar switched off the motor The time when the bar switched off the motor

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“…の使用が考えられる (Kawamoto et al, 2003) (Chen et al, 2007) The time when the bar switched off the motor The time when the bar switched off the motor …”

Section: )．しかし，コンピュータや電気式センサ等が故障し，アシストスーツの制御が不能となった場合でも患者に対する安全性mentioning

confidence: 99%

Development of a knee joint assist suit with hardware-based safety devices (Proposal and design of the assist suit)

将史

啓祐

翼

et al. 2017

Transactions of the JSME (In Japanese)

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“…The representative civil application of exoskeletons was the Robot Suit Hybrid Assistive Limb (HAL)-5 developed by Professor Yoshiyuki Sankai at University of Tsukuba for both power augmentation and walk assistance [24,25]. The hip and ankle joint of HAL-5 were actuated by a DC motor with harmonic drive for flexion/extension, respectively, and the ankle joint for flexion/extension DOF was passive with springs to return a normal angle [26].…”

Section: Climax Periodmentioning

confidence: 99%

Development of Exoskeletons and Applications on Rehabilitation

Guan

Wang

2016

MATEC Web of Conferences

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Abstract. For over a century, the development of exoskeletons experienced five periods including sprout, exploration, dormancy, accumulation and climax period from a concept in 19 th century to applications in distinctive fields in 21 th century. Recently, exoskeletons are applied in military, civilian and rehabilitation to augment the travel and loading abilities of soldiers, increase an operator's load-handling capabilities, reduce the occurrence of musculoskeletal disorders, and improve the lost functions and quality of life of patients, respectively. Aiming at lessening the strain on physical therapists to train patients with severe or degenerative disabilities, motor cognitive limitation and improving their quality of life, exoskeletons are applied on the field of rehabilitation, mainly on patient training and locomotion. Although great progress has been made in the century long effort to design and implement exoskeletons, many design challenges still remain including powered devices, the comfort of human-machine interface and how to effectively understand the wearer's intensions.

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“…RoboKnee [13] controls only the knee, using inverse dynamics without interaction with the user. More recently, in HAL of the Japanese University of Tsukuba and the Cyberdyne Systems Company (Tsukuba, Japan) [14][15][16], the joints at the hip and knee of both legs on the sagittal plane are controlled, while ankles are passive joints. The patient's Electro Miographical (EMG) signals are measured and used to synchronize precomputed walk phases and to modify the mechanical impedance which the exoskeleton presents to the patient [17].…”

Section: Introductionmentioning

confidence: 99%

Lower Limb Exoskeleton for Rehabilitation with Improved Postural Equilibrium

Menga

Ghirardi

2018

Robotics

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Abstract:In this work we present a lower limb haptic exoskeleton suitable for patient rehabilitation, specifically in the presence of illness on postural equilibrium. Exoskeletons have been mostly conceived to increase strength, while in this work patient compliance with postural equilibrium enhancement is embedded. This is achieved with two hierarchical feedback loops. The internal one, closing the loop on the joint space of the exoskeleton offers compliance to the patient in the neighborhood of a reference posture. It exploits mechanical admittance control in a position loop, measuring the patient's Electro Miographical (EMG) signals. The problem is solved using multi variable robust control theory with a two degrees of freedom setting. A second control loop is superimposed on the first one, operating on the Cartesian space so as to guarantee postural equilibrium. It controls the patient's Center of Gravity (COG) and Zero Moment Point (ZMP) by moving the internal loop reference. Special attention has been devoted to the mechanical multi-chain model of the exoskeleton which exploits Kane's method using the Autolev symbolic computational environment. The aspects covered are: the switching system between single and double stance, the system's non-holonomic nature, dependent and independent joint angles, redundancy in the torque controls and balancing weight in double stance. Physical experiments to validate the compliance method based on admittance control have been performed on an elbow joint at first. Then, to further validate the haptic interaction with the patient in a realistic situation, experiments have been conducted on a first exoskeleton prototype, while the overall system has been simulated in a realistic case study.

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Power assist method for HAL-3 using EMG-based feedback controller

Cited by 278 publications

References 1 publication

Development of a knee joint assist suit with hardware-based safety devices (Proposal and design of the assist suit)

Development of a knee joint assist suit with hardware-based safety devices (Proposal and design of the assist suit)

Development of Exoskeletons and Applications on Rehabilitation

Lower Limb Exoskeleton for Rehabilitation with Improved Postural Equilibrium

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