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Logo for the Journal of Rehab R&D
Vol. 40 No. 1, January/February 2003
Pages 39 — 48

Kinematic and dynamic performance of prosthetic knee joint using six-bar mechanism
Dewen Jin, Professor; Ruihong Zhang, PhD; HO Dimo, PhD; Rencheng Wang, PhD, Associate Professor; Jichuan Zhang, Professor
Rehabilitation Engineering Center, Department of Precision Instruments, Tsinghua University, Beijing 100084, PR China
Abstract — Six-bar linkages have been used in some prosthetic knees in the past years, but only a few publications have been written on the special functions of the mechanism as used in transfemoral prosthesis. This paper investigates the advantages of the mechanism as used in the prosthetic knee from the kinematic and dynamic points of view. Computer simulation and an experimental method were used in the investigation. The results show that the six-bar mechanism, as compared to the four-bar mechanism, can be designed to better achieve the expected trajectory of the ankle joint in swing phase. Moreover, a six-bar linkage can be designed to have more instant inactive joints than a four-bar linkage, hence making the prosthetic knee more stable in the standing phase. In the dynamic analysis, the location of the moment controller was determined for minimum value of the control moment. A testing prosthetic knee mechanism with optimum designed parameters was manufactured for experiments in the laboratory. The experimental results have verified the advantage revealed in the analyses.
Key words: dynamics, kinematics, prosthetic knee, six-bar mechanism.

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