A STUDY OF RELATED FACTORS ON VERTICAL HOPPING HEIGHT OF THE PNEUMATIC ACTUATOR

摘要

This paper reveals the influencing rules of the related factors on the hopping height of the pneumatic actuator. A hopping cycle of the pneumatic actuator includes stance phase and flight phase. By virtue of dynamics, thermodynamics, hydrodynamic, collision theory and control theory, the comprehensive mathematical model of a hopping cycle of the pneumatic actuator is proposed, which includes the procedure of foot collision to the ground, buffering stage and accelerate stage of the body in the stance phase, the shock on the body by the leg at the moment of take-off and the process of piston positioning in the flight phase. A dynamic model of a hopping cycle of the pneumatic actuator is built by Simulink tools in the form of system function (S-function). The related factors on the hopping height which are studied in this paper include: the hopping height of the previous hopping cycle, preset values of the piston position and the chambers pressure during the flight phase, control method of charging and discharge process of the cylinder during the stance phase, and so on. By theoretical analysis, simulation and experiment, the influencing rules of the related factors on the hopping height of the pneumatic actuator are discussed. The simulation results are in good agreement with the experimental results. Consequently, the obtained conclusions are valid, which can provide a reference for the hopping height control of the pneumatic actuator.