Design and analysis of a novel parallel mechanism for prosthetic knee wear test simulators

• Published in: Journal of mechanical science and technology Vol. 31; no. 2; pp. 885 - 892
• Main Authors: Daeinejad, Fatemeh S., Farahmand, Farzam, Durali, Mohammad, Abedinnasab, Mohammad H.
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Mechanical Engineers 01.02.2017; Springer Nature B.V; 대한기계학회
• Subjects: Control; Degrees of freedom; Dynamical Systems; Engineering; Industrial and Production Engineering; Kinematics; Knees; Loads (forces); Matlab; Mechanical Engineering; Mechanical knees; Parallel degrees of freedom; Prostheses; Prosthetics; Simulation; Simulators; Surgical implants; Tibial components; Vibration; Wear mechanisms; Wear tests; 기계공학; Total knee replacement (TKR); Parallel mechanisms; Kinematic analysis; Dynamic analysis; Wear test simulator
• ISSN: 1738-494X; 1976-3824
• DOI: 10.1007/s12206-017-0141-1

Using a parallel mechanism in the wear test simulators of prosthetic knees provides an easy access to the femoral and tibial components during tests. Moreover, because of its higher accuracy and load capacity, in comparison with serial mechanisms, it allows simulation of heavier tasks, such as climbing stairs, to be performed. This paper describes a new 3 Degree of freedom (DoF) spatial 2T1R (T: Translational DoF; R: Rotational DoF) parallel mechanism, for reproducing the force and motion of the tibial component of the knee prostheses in a wear test simulator. Kinematics and dynamics analysis of the mechanism indicated that it can satisfy the required DoFs, workspace and load capacity prescribed in the standard. Also, evaluation of the performance of the mechanism using the simMechanics toolbox of MATLAB revealed that it can reproduce the prescribed forces/torques with relatively high accuracy. However, the mechanism’s force outcomes were found to be affected by inaccuracies in mounting the prosthesis components, although less than the previous serial simulators. In comparison of the different possible architectures, a lateral leg angulation of 45 degrees provided the best efficacy, considering the size of actuators, the overall size of the mechanism and the accessibility of the test sample.