Pressure Control and Static Characteristic Experiments of Water Hydraulic Artificial Muscle

Due to the difference between work media employed in the water hydraulic artificial muscle (WAM) and pneumatic artificial muscle (PAM), the driving processes and characteristics are different. Aiming to analyze the static characteristics of WAM developed in our lab, a novel hydraulic pressure control circuit was proposed and a test system was designed. The experimental results of the hydraulic circuit show that the pressure can be linearly controlled in large ranges while the inputs of the water hydraulic proportional throttle valve in the circuit were limited from 10% to 90%. As well, the theoretical relationship among the contraction, pressure and output drawing force of WAM was tested and verified through static drive experiments. The WAM prototype works well to generate a drawing force of at least 14 kN and can be driven at 4 MPa. The model parameters of WAM were obtained through experiments and the comparative analysis of experimental results and the present static model of WAM. These contribute to the researches on drive characteristic and WAM control systems.