Tiny hydraulics for powered orthotics

Durfee, William K.; Xia, Jicheng; Hsiao-Wecksler, Elizabeth T.

doi:10.1109/icorr.2011.5975473

Cited by 14 publications

(8 citation statements)

References 13 publications

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“…More importantly, our results validate a linear relationship between input pressure and output torque that is independent of joint angle. For preliminary assessment, the accumulator was pressurized using a simple hand pump; however, automated pumps and motors capable of producing required pressures with reasonable weight and power consumption for portable use are available [ 28 ] and can be integrated into the PAS in the future now that feasibility of the approach has been established.…”

Section: Discussionmentioning

confidence: 99%

“…Keeping the mass proximal allows it to be directly transferred to the ground and is not carried by the user or an external power source [ 25 ]. Suitable wearable miniature hydraulic pumps are currently being developed [ 28 ] and adding this unit to our current exoskeleton prototype will keep the weight ( Table 1 ) at or below clinically available electrically driven exoskeletons [ 29 ].…”

Section: Methodsmentioning

confidence: 99%

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Feasibility of a Hydraulic Power Assist System for Use in Hybrid Neuroprostheses

Foglyano

Kobetic

et al. 2015

Applied Bionics and Biomechanics

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Feasibility of using pressurized hydraulic fluid as a source of on-demand assistive power for hybrid neuroprosthesis combining exoskeleton with functional neuromuscular stimulation was explored. Hydraulic systems were selected as an alternative to electric motors for their high torque/mass ratio and ability to be located proximally on the exoskeleton and distribute power distally to assist in moving the joints. The power assist system (PAS) was designed and constructed using off-the-shelf components to test the feasibility of using high pressure fluid from an accumulator to provide assistive torque to an exoskeletal hip joint. The PAS was able to provide 21 Nm of assistive torque at an input pressure of 3171 kPa with a response time of 93 ms resulting in 32° of hip flexion in an able-bodied test. The torque output was independent of initial position of the joint and was linearly related to pressure. Thus, accumulator pressure can be specified to provide assistive torque as needed in exoskeletal devices for walking or stair climbing beyond those possible either volitionally or with electrical stimulation alone.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Feasibility of a Hydraulic Power Assist System for Use in Hybrid Neuroprostheses

Foglyano

Kobetic

et al. 2015

Applied Bionics and Biomechanics

View full text Add to dashboard Cite

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“…Current off-the-shelf pressure sources are generally limited to compressors and compressed air cylinders, 25 while recent literature has shown a promising explosive actuation modality for soft robots by combustion. 8 In previous work, we have utilized both pressure sources.…”

Section: Energy: Portable Pneumatic Batterymentioning

confidence: 99%

System-level challenges in pressure-operated soft robotics

Önal

2016

SPIE Proceedings

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Last decade witnessed the revival of fluidic soft actuation. As pressure-operated soft robotics becomes more popular with promising recent results, system integration remains an outstanding challenge. Inspired greatly by biology, we envision future robotic systems to embrace mechanical compliance with bodies composed of soft and hard components as well as electronic and sensing sub-systems, such that robot maintenance starts to resemble surgery. In this vision, portable energy sources and driving infrastructure plays a key role to offer autonomous many-DoF soft actuation. On the other hand, while offering many advantages in safety and adaptability to interact with unstructured environments, objects, and human bodies, mechanical compliance also violates many inherent assumptions in traditional rigid-body robotics. Thus, a complete soft robotic system requires new approaches to utilize proprioception that provides rich sensory information while remaining flexible, and motion control under significant time delay. This paper discusses our proposed solutions for each of these system-level challenges in soft robotics research.

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“…Roland Auberger, Michael Friedrich Russold, Robert Riener, Hans Dietl C force and power with a high power/weight ratio [17], especially if hydraulics is used as a passive damper only. However, the control possibilities are limited.…”

Section: Patient Motion Using a Computerized Leg Brace In Everyday Lomentioning

confidence: 99%

Patient Motion Using a Computerized Leg Brace in Everyday Locomotion Tasks

Auberger

Russold

Riener³

et al. 2019

IEEE Trans. Med. Robot. Bionics

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Exoskeletal systems are becoming a rehabilitation standard of care for persons with lower limb paralysis. As muscular dysfunctions affect a heterogeneous patient group, each individual develops their own strategy to negotiate everyday locomotion challenges. This paper introduces a microprocessor controlled orthotic system that passively supports people with lower limb paralyses in their everyday locomotion tasks while incorporating the user as the highest control entity. A clinical study with seven patients with a range of leg pareses investigated the functionality and usage of the system while capturing the mechanical stress on the device. Data from the knee joint was recorded in locomotion tasks including level walking, ramp and stair negotiation. For all patients the measurements demonstrate that the motion for level walking was close to the motion of healthy individuals. In other tasks, variations between the patients were large with respect to motion kinematics, power and torque requirements. As the control concept supported individualized motion patterns, patients perceived the system functionality as intuitive. The mechanically most demanding task was stair descent with a peak torque of 1.47 Nm/kg and peak dissipative power up to 2.67 W/kg. Intra-subject variability makes prediction of movements and loads challenging.

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Tiny hydraulics for powered orthotics

Cited by 14 publications

References 13 publications

Feasibility of a Hydraulic Power Assist System for Use in Hybrid Neuroprostheses

Feasibility of a Hydraulic Power Assist System for Use in Hybrid Neuroprostheses

System-level challenges in pressure-operated soft robotics

Patient Motion Using a Computerized Leg Brace in Everyday Locomotion Tasks

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