Dynamically Controlled Ankle-Foot Orthosis (DCO) with Regenerative Kinetics: Incrementally Attaining User Portability

Hitt, Joseph K.; Oymagil, A.M.; Sugar, Thomas G.; Hollander, Kevin W.; Boehler, Alex; Fleeger, J.

doi:10.1109/robot.2007.363543

Cited by 54 publications

(46 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Robotic devices with active assistance show promise for improving locomotor performance for people with lower-limb amputation [13][14][15][16][17][18][19]. For example, the first robotic ankle-foot prosthesis to reduce the energetic cost of walking for amputees has recently been demonstrated [20].…”

Section: Introductionmentioning

confidence: 99%

“…Experimental studies are therefore crucial to evaluating the effects of a proposed design on humans, but such tests require a physical device that can be worn and used by a person. This has led to the development of product-like prototypes, each embodying a candidate functionality (we use this term in the manner of [28]), and each requiring several years of design and refinement prior to evaluation by human users [14][15][16]20,21,29]. Autonomy presents the greatest design challenge, leading to specialized devices that are not versatile enough to express other candidate functionalities.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Universal Ankle–Foot Prosthesis Emulator for Human Locomotion Experiments

Caputo

Collins

2014

Journal of Biomechanical Engineering

139

107

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Universal Ankle–Foot Prosthesis Emulator for Human Locomotion Experiments

Caputo

Collins

2014

Journal of Biomechanical Engineering

139

107

View full text Add to dashboard Cite

show abstract

“…Switch between ascending and level walking is handled by detecting how the ground contact is made toe (8) or hill (7).…”

Section: ) Level Walkingmentioning

confidence: 99%

“…With force transducers and a rotary potentiometer gait phases were detected by comparing with thresholds. Hitt et al proposed an actuator control which followed an individual ankle angle trajectory where the spring allowed the motion to differ [8]. The system was continuously updated for gait speed variations by a variable time-base of the trajectory.…”

Section: Introductionmentioning

confidence: 99%

Ankle-Foot-Orthosis Control in Inclinations and Stairs

Svensson

Holmberg

2008

2008 IEEE Conference on Robotics, Automation and Mechatronics

View full text Add to dashboard Cite

Abstract-A control procedure is proposed for an ankle-footorthosis (AFO) for different gait situations, such as inclinations and stairs. This paper presents a novel AFO control of the ankle angle. A magneto-rheological damper was used to achieve ankle damping during foot down and locking at swing, thereby avoiding foot slap as well as foot drop.The controller used feedback from the ankle angle only. Still it was capable of not only adjusting damping within a gait step but also changing control behavior depending on level walking, ascending and descending stairs. As a consequence, toe strike was possible in stair gait as opposed to heel strike in level walking. Tests verified the expected behavior in stair gait and in level walking where gait speed and ground inclinations varied. The self-adjusted AFO is believed to improve gait comfort in slopes and stairs.

show abstract

“…In general, current devices fall into two distinct categories (1) fullypowered [6][7][8][9] and (2) purely passive [10]. Fully-powered devices employ motors under high gain force control that can mimic the normal torque output of the lower-limb joints over the full gait cycle.…”

Section: Introductionmentioning

confidence: 99%

An exoskeleton using controlled energy storage and release to aid ankle propulsion

Wiggin

Sawicki

Collins

2011

2011 IEEE International Conference on Rehabilitation Robotics

View full text Add to dashboard Cite

-Symmetric ankle propulsion is the cornerstone of efficient human walking. The ankle plantar flexors provide the majority of the mechanical work for the step-to-step transition and much of this work is delivered via elastic recoil from the Achilles' tendon -making it highly efficient. Even though the plantar flexors play a central role in propulsion, body-weight support and swing initiation during walking, very few assistive devices have focused on aiding ankle plantarflexion. Our goal was to develop a portable ankle exoskeleton taking inspiration from the passive elastic mechanisms at play in the human triceps surae-Achilles' tendon complex during walking. The challenge was to use parallel springs to provide ankle joint mechanical assistance during stance phase but allow free ankle rotation during swing phase. To do this we developed a novel 'smartclutch' that can engage and disengage a parallel spring based only on ankle kinematic state. The system is purely passivecontaining no motors, electronics or external power supply. This 'energy-neutral' ankle exoskeleton could be used to restore symmetry and reduce metabolic energy expenditure of walking in populations with weak ankle plantar flexors (e.g. stroke, spinal cord injury, normal aging).Keywords-human walking, ankle exoskeleton, plantar flexors, elastic energy storage and return, passive dynamics, 'energyneutral', metabolic cost I. BACKGROUNDCoordinated ankle propulsion is a critical factor for efficient human walking. The ankle plantar flexors contribute the majority of the mechanical work done on the center-of-mass during push-off (Phase 4, 50-60% Stride) (Fig. 1). The efficiency of human gait is particularly impacted by the timing of the push-off and collision impulsive ground reaction forces [1]. For example, following stroke, propulsive impulses delivered by the ankle plantar flexors are often highly asymmetric. Push-off asymmetry results in slow walking speeds and increased metabolic energy consumption [3][4][5]. Due to the vital role of the ankle plantar flexors in shaping the normal mechanics and energetics of walking, it is essential to investigate ways in which we can improve gait impairments by focusing on aiding ankle joint push-off.Portable wearable robotic devices hold considerable promise for restoring ankle function in populations with musculoskeletal or neurological impairments. In general, current devices fall into two distinct categories (1) fullypowered [6-9] and (2) purely passive [10]. Fully-powered devices employ motors under high gain force control that can mimic the normal torque output of the lower-limb joints over the full gait cycle. Some major downsides to this approach are that powerful motors are heavy, require bulky gears and mounting frames, and rely on finite power sources that must be donned by the user. The consequence of this added mass is a marked decrease in walking economy (i.e. no metabolic savings) during assisted locomotion with portable powered devices.

show abstract

Dynamically Controlled Ankle-Foot Orthosis (DCO) with Regenerative Kinetics: Incrementally Attaining User Portability

Cited by 54 publications

References 25 publications

A Universal Ankle–Foot Prosthesis Emulator for Human Locomotion Experiments

A Universal Ankle–Foot Prosthesis Emulator for Human Locomotion Experiments

Ankle-Foot-Orthosis Control in Inclinations and Stairs

An exoskeleton using controlled energy storage and release to aid ankle propulsion

Contact Info

Product

Resources

About