Research On Control System Of Frog-inspired Swimming Leg Powered By Pneumatic Muscle

Research on bionic swimming robots in recent years has become popular to adapt to the complicated aquatic environment. Given its excellent amphibious abilities, it is of great importance and practical value to develop frog inspired robot. A frog inspired leg driven by pneumatic muscles was designed according to real frog structure. Meanwhile, an experimental platform for antagonistic joint was designed, and the joint dynamic model was developed. The control strategy for antagonistic joint was carried out and validated via simulations and experiments.Firstly, according to the shortages of previous generation of frog inspired robot, 3D model of frog inspired leg was designed based on the concept of antagonistic joint. The webbed foot design was improved. Kinematic model of frog inspired leg was built by D-H method and the leg design was validated by simulations.Secondly, the dynamic model of antagonistic joint based on advanced pneumatic muscle model was established in Matlab/Simulink environment. Th e nonlinear relationship between joint angle and pneumatic muscle output was derived in the designed experimental platform for antagonistic joint. Response results of dynamic model simulations and experiments were compared and parameters of simulation model were revised to improve the performance of the dynamic model.Besides, the servo control strategy of joint angle was studied based on the dynamic model of antagonistic joint. The PID and self-tuning fuzzy control were utilized to control the antagonistic joint, and their validities were verified. Control programs based on PID and self-tuning fuzzy control were written in Lab VIEW, and their feasibilities were validated via step response experiments with different loads on antagonistic joint and trajectory tracking experiments with large load.Finally, the experiment platform was established to carry out position and attitude adjusting experiment and robot control experiment with the developed frog-inspired swimming leg. And the feasibility of antagonistic frog inspired swimming leg driven by pneumatic muscles was validated.