Antagonistic active knee prosthesis. A metabolic cost of walking comparison with a variable-damping prosthetic knee

Martinez-Villalpando, Ernesto C.; Mooney, Luke M.; Elliott, Grant; Herr, Hugh M.

doi:10.1109/iembs.2011.6092102

Cited by 43 publications

(24 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…FSC is far-and-away the most popular mid-level control approach. Many groups have successfully implemented FSCs using different numbers of activities and states with a wide variety of devices [ 2 , 3 , 14 , 24 , 41 , 44 , 107 – 109 , 114 , 117 , 118 , 121 , 123 , 124 , 134 , 137 – 139 , 143 , 150 , 163 , 171 – 186 ].…”

Section: Control Strategiesmentioning

confidence: 99%

“…Aside from improvements in amplifier or transmission technology, energy-saving approaches include the use of passive compliance, e.g. [ 3 , 205 , 222 ], mechanically-variable impedance actuation [ 223 , 224 ] and the reciprocal transfer of power between joints [ 213 , 225 – 228 ] or between portions of the gait cycle [ 229 – 231 ].…”

Section: The P/o Devicementioning

confidence: 99%

See 1 more Smart Citation

Control strategies for active lower extremity prosthetics and orthotics: a review

Tucker¹,

Olivier

Pagel³

et al. 2015

J NeuroEngineering Rehabil

821

591

View full text Add to dashboard Cite

Technological advancements have led to the development of numerous wearable robotic devices for the physical assistance and restoration of human locomotion. While many challenges remain with respect to the mechanical design of such devices, it is at least equally challenging and important to develop strategies to control them in concert with the intentions of the user.This work reviews the state-of-the-art techniques for controlling portable active lower limb prosthetic and orthotic (P/O) devices in the context of locomotive activities of daily living (ADL), and considers how these can be interfaced with the user’s sensory-motor control system. This review underscores the practical challenges and opportunities associated with P/O control, which can be used to accelerate future developments in this field. Furthermore, this work provides a classification scheme for the comparison of the various control strategies.As a novel contribution, a general framework for the control of portable gait-assistance devices is proposed. This framework accounts for the physical and informatic interactions between the controller, the user, the environment, and the mechanical device itself. Such a treatment of P/Os – not as independent devices, but as actors within an ecosystem – is suggested to be necessary to structure the next generation of intelligent and multifunctional controllers.Each element of the proposed framework is discussed with respect to the role that it plays in the assistance of locomotion, along with how its states can be sensed as inputs to the controller. The reviewed controllers are shown to fit within different levels of a hierarchical scheme, which loosely resembles the structure and functionality of the nominal human central nervous system (CNS). Active and passive safety mechanisms are considered to be central aspects underlying all of P/O design and control, and are shown to be critical for regulatory approval of such devices for real-world use.The works discussed herein provide evidence that, while we are getting ever closer, significant challenges still exist for the development of controllers for portable powered P/O devices that can seamlessly integrate with the user’s neuromusculoskeletal system and are practical for use in locomotive ADL.

show abstract

Section: Control Strategiesmentioning

confidence: 99%

Section: The P/o Devicementioning

confidence: 99%

Control strategies for active lower extremity prosthetics and orthotics: a review

Tucker¹,

Olivier

Pagel³

et al. 2015

J NeuroEngineering Rehabil

821

591

View full text Add to dashboard Cite

show abstract

“…The device tested in this study was the VI Knee [ 29 ], a powered prosthetic knee developed at The Massachusetts Institute of Technology (MIT). Eleven unilateral, PWAs above the knee were recruited through connections with local prosthetists based on the following inclusion criteria: Height over 1.5 m, weight between 83 and 113 kg, age between 20 and 70 years, and rated as a level K3 or above ambulator (defined as being able to voluntarily vary walking speed and walk without hand-held assistive devices), and be experienced (greater than 1 year) C-Leg users.…”

Section: Methodsmentioning

confidence: 99%

“…Variable impedance control adjusts the knee output torque (either braking or producing positive torque) as a function of its rotational velocity, thereby producing a more biomimetic gait. In early studies, individuals with above knee amputations walking on level ground at their normal, customary walking speed were observed to have a 6.8 % reduction in their metabolic effort due to using this device compared to their conventional prosthesis [ 29 ].…”

Section: Introductionmentioning

confidence: 99%

Impact on gait biomechanics of using an active variable impedance prosthetic knee

Williams

D’Andrea

Herr

2016

J NeuroEngineering Rehabil

View full text Add to dashboard Cite

BackgroundAn above knee amputation can have a significant impact on gait, with substantial deviations in inter-leg symmetry, step length, hip exertion and upper body involvement even when using a current clinical standard of care prosthesis. These differences can produce gait that is less efficient and less comfortable, resulting in slower and shorter distance walking, particularly with long term use.MethodsA robotic variable impedance prosthetic knee (VI Knee) was tested with five individuals (N = 5) with unilateral amputation above the knee at fixed speeds both above and below their normal walking speed. Subject gait was measured as they walked along an instrumented walkway via optical motion capture and force plates in the floor. Each subject’s gait while using the VI Knee was compared to that while using their standard of care knee (OttoBock C-Leg).ResultsSignificant differences (p < 0.05) in walking between the standard of care and variable impedance devices were seen in step length and hip range of motion symmetries, hip extension moment, knee power and torso lean angle. While using the VI Knee, several subjects demonstrated statistically significant improvements in gait, particularly in increased hip range of motion symmetry between affected and intact sides, greater prosthesis knee power and in reducing upper body involvement in the walking task by decreasing forward and affected side lean and reducing the pelvis-torso twist coupling. These changes to torso posture during gait also resulted in increased terminal stance hip flexion moment across subjects. Detriments to gait were also observed in that some subjects exhibited decreased step length symmetry while using the VI Knee compared to the C-Leg.ConclusionsThe knee tested represents the potential to improve gait biomechanics and reduce upper body involvement in persons with above knee amputation compared to current standard of care devices. While using the VI Knee, subjects demonstrated statistically significant improvements in several aspects of gait though some were worsened while using the device. It is possible that these negative effects may be mitigated through longer term training and experience with the VI Knee. Given the demonstrated benefits and the potential to reduce or eliminate detriments through training, using a powered device like the VI Knee, particularly over an extended period of time, may help to improve walking performance and comfort.

show abstract

“…Such a variable-impedance control allows the knee to adjust its output (producing positive elastic torque or braking torque) in relation to its rotational state (position and velocity) to replicate a more natural gait, enhancing metabolic effectiveness. In preliminary studies, individuals with transfemoral amputation walking at their customary speed over level ground were found to have reduced their metabolic effort by 6.8 percent while walking with this knee compared with their normal variable-damping prosthesis, despite its greater mass (2.5 kg vs 1.5 kg for C-Leg with pylon and fittings) [26].…”

Section: Introductionmentioning

confidence: 99%

Metabolic effects of using a variable impedance prosthetic knee

2016

View full text Add to dashboard Cite

Abstract-A transfemoral amputation has a significant effect on walking. Though current prosthetic knee options serve to restore mobility, as purely passive devices, they do not fully restore nondisabled gait. Persons with transfemoral amputation incur a higher metabolic cost during walking than persons without amputation and as a result walk slower and for shorter distances before tiring. An original variable-impedance transmission prosthetic knee (VI Knee) was tested in five study participants with unilateral transfemoral amputation at two steadystate walking speeds, one below and one above their preferred walking speed. While walking with the VI Knee, participants with shorter limbs showed a reduction in metabolic cost compared with their conventional C-Leg prosthesis, while those with longer limbs exhibited an increase. Though differences were observed between speeds, overall the difference in metabolic cost (reduction or increase) was found to correlate significantly with rise in the center of mass, with those with shorter residual limbs exhibiting less overall lifting of the body during gait.

show abstract

Antagonistic active knee prosthesis. A metabolic cost of walking comparison with a variable-damping prosthetic knee

Cited by 43 publications

References 15 publications

Control strategies for active lower extremity prosthetics and orthotics: a review

Control strategies for active lower extremity prosthetics and orthotics: a review

Impact on gait biomechanics of using an active variable impedance prosthetic knee

Metabolic effects of using a variable impedance prosthetic knee

Contact Info

Product

Resources

About