Towards local reflexive control of a powered transfemoral prosthesis for robust amputee push and trip recovery

2014 ◽  
Author(s):  
Nitish Thatte ◽  
Hartmut Geyer
Keyword(s):  
Transfemoral Prosthesis ◽  
Trip Recovery

PROTOTYPE OF TRANSFEMORAL PROSTHESIS WITH AN ACTIVE ARTIFICIAL KNEE

2020 ◽  
Vol 4 (1) ◽  
pp. 172-180
Author(s):  
A.M. POLIAKOV ◽  
P.K. SOPIN ◽  
V.B. LAZAREV ◽  
A.I. RYZHKOV ◽  
M.A. KOLESOVA ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Control System ◽  
Knee Joint ◽  
Hierarchical Control ◽  
Control Level ◽  
Quality Criteria ◽  
Optimal Conditions ◽  
Invariant Moments ◽  
Biological Similarity ◽  
Transfemoral Prosthesis

This article presents a transfemoral prosthesis prototype with active control of an artificial knee joint. One of the main criteria used in the design of the prosthesis was to achieve the maximum biological similarity of this device in order to provide optimal conditions conducive to user natural walking. The artificial knee joint, designed on the basis of a polycentric higed mechanism with intersecting links, provides such conditions at the design level, and a three-level hierarchical control system, built on the basis of an intelligent-synergetic concept, at the control level. To recognize user's intentions, the intelligent subsystem uses algorithms for comparing graphic images of user's walking phases by the method of estimating the invariant moments of Hu. After that, prosthesis elements movements are planned in the synergistic subsystem in accordance with the synergistic quality criteria. The algorithms used in the control system are adjusted depending on what type of artificial foot is used in the prosthesis: active, semi-active or passive (purely mechanical). Mathematical modeling of the prosthesis operation shows that the nature of its functioning corresponds to the quality criteria adopted in the design.

The Design and Initial Experimental Validation of an Active Myoelectric Transfemoral Prosthesis

2012 ◽  
Vol 6 (1) ◽  
Author(s):  
Carl D. Hoover ◽  
George D. Fulk ◽  
Kevin B. Fite
Keyword(s):  
Neuromuscular Control ◽  
Surface Emg ◽  
Myoelectric Control ◽  
Control Architecture ◽  
Single Subject ◽  
Test Bed ◽  
Real Time Control ◽  
Joint Power ◽  
Time Control ◽  
Transfemoral Prosthesis

This paper describes a single degree-of-freedom active-knee transfemoral prosthesis to be used as a test bed for the development of architectures for myoelectric control. The development of an active-knee transfemoral prosthesis is motivated by the inability of passive commercial prostheses to provide the joint power required at the knee for many activities of daily living such as reciprocal stair ascent, which requires knee power outputs of up to 4 W/kg. Study of myoelectric control based on surface electromyogram (EMG) measurements of muscles in the residual limb is motivated by the desire to restore direct volitional control of the knee using a minimally-invasive neuromuscular control interface. The presented work describes the design of a transfemoral prosthesis prototype including the structure, actuation, instrumentation, electronics, and real-time control architecture. The performance characteristics of the prototype are discussed in the context of the requisite knee energetics for a variety of common locomotive functions. This paper additionally describes the development of a single-subject diagnostic socket with wall-embedded surface EMG electrodes and the implementation of a control architecture for myoelectric modulation of knee impedance. Experimental results of level walking for a single subject with unilateral transfemoral amputation demonstrate the potential for direct EMG-based control of locomotive function.

Myoelectric Torque Control of an Active Transfemoral Prosthesis During Stair Ascent

2011 ◽  
Author(s):  
Carl D. Hoover ◽  
Kevin B. Fite ◽  
George D. Fulk ◽  
Donald W. Holmes
Keyword(s):  
Impedance Control ◽  
Torque Control ◽  
Motion Capture Data ◽  
Clinical Tests ◽  
Joint Kinetics ◽  
Set Point ◽  
Stair Ascent ◽  
Normal Gait ◽  
Stiffness And Damping ◽  
Transfemoral Prosthesis

This paper presents experimental results of a myoelectric impedance controller designed for reciprocal stair ascent with an active-knee powered transfemoral prosthesis. The controller is modeled from non-amputee (normal) motion capture data, estimating knee torque with a linear two-state (stance/swing) impedance control form that includes proportional myoelectric torque control. The normal gait model is characterized by small stiffness and damping in both stance and swing, a low angle set-point in stance, a high angle set-point in swing, and proportional myoelectric control in stance but not swing. Clinical tests with a single unilateral transfemoral amputee indicate good performance of the controller; however, subject feedback suggests a reduction in the extensive myoelectric torque parameter and the need for constant, balanced myoelectric torque parameters in both stance and swing. Average prosthesis knee joint kinetics from a stairwell test using the amputee-tuned controller compare favorably with non-amputee gait data.

A Computer Model to Simulate the Swing Phase of a Transfemoral Prosthesis

2004 ◽  
Vol 20 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Brendan Burkett ◽  
James Smeathers ◽  
Timothy M. Barker
Keyword(s):  
Walking Speed ◽  
Swing Phase ◽  
Prosthetic Knee ◽  
Energy Demands ◽  
Swing Time ◽  
Significant Difference ◽  
Prosthetic Knee Joint ◽  
Transfemoral Prosthesis ◽  
Everyday Task ◽  
Phase Motion

For amputees to perform an everyday task, or to participate in physical exercise, it is crucial that they have an appropriately designed and functional prosthesis. Past studies of transfemoral amputee gait have identified several limitations in the performance of amputees and in their prosthesis when compared with able-bodied walking, such as asymmetrical gait, slower walking speed, and higher energy demands. In particular the different inertial characteristics of the prosthesis relative to the sound limb results in a longer swing time for the prosthesis. The aim of this study was to determine whether this longer swing time could be addressed by modifying the alignment of the prosthesis. The following hypothesis was tested: Can the inertial characteristics of the prosthesis be improved by lowering the prosthetic knee joint, thereby producing a faster swing time? To test this hypothesis, a simple 2-D mathematical model was developed to simulate the swing-phase motion of the prosthetic leg. The model applies forward dynamics to the measured hip moment of the amputee in conjunction with the inertial characteristics of prosthetic components to predict the swing-phase motion. To evaluate the model and measure any change in prosthetic function, we conducted a kinematic analysis on four Paralympic runners as they ran. When evaluated, there was no significant difference (p > 0.05) between predicted and measured swing time. Of particular interest was how swing time was affected by changes in the position of the prosthetic knee axis. The model suggested that lowering the axis of the prosthetic knee could reduce the longer swing time. This hypothesis was confirmed when tested on the amputee runners.

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