Design and Control of a Nonlinear Series Elastic Cable Actuator Based on the Hill Muscle Model

Abstract

The bionic design of muscles is a research hotspot at present. Many researchers have designed bionic elastic actuators based on the Hill muscle model, and most of them include an active contraction element, passive contraction element and series elastic element, but they need more parametric design of mechanical structure and control under the guidance of Hill muscle model. In this research, a nonlinear series elastic cable actuating mechanism is designed in which the parameters of the elastic mechanism are optimized based on the Hill muscle model to fit the nonlinear passive elasticity of a muscle. Through the force–position relationship determined by the Hill muscle model, the output force and position of a nonlinear series elastic cable actuator are controlled to simulate the active contraction performance of a muscle. The experiments show that the proposed design and control method can make the nonlinear cable actuator have good muscle-like output force–displacement characteristics.

Neuromechanics-Based Neural Feedback Controller for Planar Arm Reaching Movements

“…The force produced by the PEC is dependent on the forces generated by the CC and SEC. The formula for it is described as follows [ 33 ]: where , , and are the PEC force, SEC force, and the total force exerting on the muscle tendon, respectively.…”

Physical based motion reconstruction from videos using musculoskeletal model

“…The Hill three‐element muscle model 36,37 is a widely used tool for analyzing the mechanical properties and movement mechanisms of muscles in biomechanical research. As depicted in Figure 3, this muscle model includes three main components: a contractile element (CE) represents the active properties of the muscle fibers, which generate the active force $$$ {f}_{\mathrm{CE}} $$$ when the muscle is elongated or contracted; a passive elastic element (PE) represents the passive stiffness of the muscle fibers, which ensures the shape and stability of the muscle and generates the passive force $$$ {f}_{\mathrm{PE}} $$$; and a tandem elastic element (SE) represents the elasticity of the tendons connecting the muscle to the bone and generates the passive force $$$ {f}_{\mathrm{SE}} $$$.…”