|Optimization and Comparison of Typical Elastic Actuators in Powered Ankle-foot Prosthesis
Jingjing Liu, Noor Azuan Abu Osman*, Mouaz Al Kouzbary, Hamza Al Kouzbary, Nasrul Anuar Abd Razak, Hanie Nadia Shasmin, and Nooranida Arifin
International Journal of Control, Automation, and Systems, vol. 20, no. 1, pp.232-242, 2022
Abstract : Elastic actuators are broadly applied in the design of the powered ankle-foot prosthesis, so it is a significant task to select and optimize a suitable elastic actuator. Dynamic models of seven kinds of elastic actuators are constructed from a two-degrees-of-freedom vibration system in rotation. With input parameters from sound ankle data during walking, motor data, and the three-dimensional model of the proposed prosthesis, two objectives, which are to minimize the peak mechanical power and mean energy consumption power of the motor, respectively, are optimized by changing the parameters of elastic elements. Unidirectional parallel elastic actuator (UPEA) and UPEA with series spring (SE+UPEA) optimize nearly 75% compared to the direct-driver actuator (DDA) in minimizing the characteristic of peak mechanical power. When it comes to reducing mean energy consumption power, UPEA is also the best, and its performance is at least 15% better than those of the other four kinds of elastic actuators with effective optimization. Besides, features of torque and velocity on the driver end are also compared from elastic actuators to sound ankle. The comparison contributes to understanding the optimization mechanism of different elastic elements, and the optimized and compared performances of elastic actuators can be utilized as the selection basis in the design of the powered ankle-foot prosthesis.
Dynamics, elastic actuators, optimization, powered ankle-foot prosthesis.
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