Robotic transtibial prosthesis with biomechanical energy regeneration

Hitt, Joseph K.; Sugar, Thomas G.; Holgate, Matthew; Bellman, Ryan; Hollander, Kevin W.

doi:10.1108/01439910910980169

Cited by 107 publications

(56 citation statements)

References 23 publications

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“…Benchtop tests revealed higher closed-loop torque bandwidth than the highest open-loop bandwidth values reported for prior designs (17 Hz vs. 14 Hz in [4]), but with less than half the mass. The testbed exhibited higher peak torque (175 N·m vs. 134 N·m in [4]) and peak power (1006 W vs. 270 W in [25]) than prior experimental results. These results also compare well with observations of the human ankle and foot.…”

Section: Discussioncontrasting

confidence: 54%

An experimental robotic testbed for accelerated development of ankle prostheses

Caputo

Collins

2013

2013 IEEE International Conference on Robotics and Automation

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Biomechatronic devices show promise for restoring human performance, but development has been made inefficient by the need for specialized autonomous devices prior to testing benefits of proposed functionalities. This has severely limited exploration within and across intervention strategies. We have developed a laboratory testbed suitable for emulating and rapidly assessing wearable robot designs. The testbed is comprised of powerful off-board motor and control hardware, a flexible tether, and lightweight instrumented end-effectors worn by a person. We performed a series of benchtop tests to gauge mechatronic performance, and found significant improvements over prior candidate testbed platforms. In particular, this system has an unusual combination of low worn mass (less than 1 kg), high closed-loop torque bandwidth (17 Hz), and high peak torque (175 N·m), key to emulating specialized devices. We also performed walking trials to gauge dynamic torque control and versatility. Walking trials with a prosthesis end-effector demonstrated precise torque tracking (4 N·m RMS error), both in time and joint-angle space, and versatile mechanical behavior through systematic changes in high-level control law parameters. For example, we widely varied net ankle work (from -3 J to 9 J per step) using an impedance law relating joint angle and velocity to desired torque. These results suggest such testbeds could be used to emulate and evaluate novel assistive robot concepts prior to laborious product design.

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Section: Discussioncontrasting

confidence: 54%

An experimental robotic testbed for accelerated development of ankle prostheses

Caputo

Collins

2013

2013 IEEE International Conference on Robotics and Automation

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“…Transactions of the ASME in [55]) than prior experimental results. These results also compare well with observations of the human ankle and foot.…”

Section: -6 / Vol 136 March 2014mentioning

confidence: 73%

A Universal Ankle–Foot Prosthesis Emulator for Human Locomotion Experiments

Caputo

Collins

2014

Journal of Biomechanical Engineering

139

107

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Robotic prostheses have the potential to significantly improve mobility for people with lower-limb amputation. Humans exhibit complex responses to mechanical interactions with these devices, however, and computational models are not yet able to predict such responses meaningfully. Experiments therefore play a critical role in development, but have been limited by the use of productlike prototypes, each requiring years of development and specialized for a narrow range of functions. Here we describe a robotic ankle-foot prosthesis system that enables rapid exploration of a wide range of dynamical behaviors in experiments with human subjects. This emulator comprises powerful off-board motor and control hardware, a flexible Bowden cable tether, and a lightweight instrumented prosthesis, resulting in a combination of low mass worn by the human (0.96 kg) and high mechatronic performance compared to prior platforms. Benchtop tests demonstrated closedloop torque bandwidth of 17 Hz, peak torque of 175 Nm, and peak power of 1.0 kW. Tests with an anthropomorphic pendulum "leg" demonstrated low interference from the tether, less than 1 Nm about the hip. This combination of low worn mass, high bandwidth, high torque, and unrestricted movement makes the platform exceptionally versatile. To demonstrate suitability for human experiments, we performed preliminary tests in which a subject with unilateral transtibial amputation walked on a treadmill at 1.25 ms À1 while the prosthesis behaved in various ways. These tests revealed low torque tracking error (RMS error of 2.8 Nm) and the capacity to systematically vary work production or absorption across a broad range (from À5 to 21 J per step). These results support the use of robotic emulators during early stage assessment of proposed device functionalities and for scientific study of fundamental aspects of human-robot interaction. The design of simple, alternate end-effectors would enable studies at other joints or with additional degrees of freedom.

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“…Several prototypes of ankle-foot prostheses are already using this mechanisms [4][5][6]. There is one active knee joint prototype operated as an DD [7] and one with an antagonistic SEA-system [8].…”

Section: Introductionmentioning

confidence: 99%

Stiffness adjustment of a series elastic actuator in a knee prosthesis for walking and running: The trade-off between energy and peak power optimization

Grimmer

Seyfarth

2011

2011 IEEE/RSJ International Conference on Intelligent Robots and Systems

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In ankle-foot prostheses a serial spring can assist the motor to reduce peak power (PP) and energy requirements (ER) during locomotion. Similar benefits can be expected for an active knee prosthesis. We compare the situation of a direct drive with a series elastic actuator optimized for minimal ER or for minimal PP. The simulations indicate that at the knee joint a serial spring can highly reduce ER and PP in running and fast walking. Around preferred walking speed (1.3m/s) only a reduction in ER is found. The optimal stiffness changes with speed and gait. Still it is possible to use one constant stiffness for a huge range of walking and running speeds with only moderate increases of ER and PP in comparison to speed and gait optimized values.

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Robotic transtibial prosthesis with biomechanical energy regeneration

Cited by 107 publications

References 23 publications

An experimental robotic testbed for accelerated development of ankle prostheses

An experimental robotic testbed for accelerated development of ankle prostheses

A Universal Ankle–Foot Prosthesis Emulator for Human Locomotion Experiments

Stiffness adjustment of a series elastic actuator in a knee prosthesis for walking and running: The trade-off between energy and peak power optimization

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