Research On Design And Control Strategy Of Pneumatic Muscle-based Biped Robot

From the 1960 s, the biped robots has got more and more attention from the scholars all over the world and got huge development. Since all joints of the active robots need to be actuated, the choice of the drive is very important. The past active robots are mainly actuated by motors. Although the motors can help the robot get precise position, this kind of robot can not walk as human beings. During this circumstance, the pneumatic muscle is choosed for its compliance, high power/mass ratio and similarity to human muscles. To deep study the characteristics of the biped robots actuated by pneumatic muscles and improve their walking stability, this paper puts forward to the designing of the biped robot actuated by pneumatic muscles, based on the human muscle model of lower limbs. The walking trajectory of the robot is planned through ZMP method. The walking of the robot is controlled through the method of PID and fuzzy control. Besides, to study the rationality and walking stability of the designed robot, the robot prototype is made.Firstly, this paper studies the driving mechanism of the human muscle model of lower limbs. According to the existing nine-muscle model and human walking simulation results of the human body dynamics simulation software Life MOD, the force curve of the muscles and angle curve of every joint are got. The biped robot is designed on the basis of human muscle model of lower limbs.Secondly, this paper studies the dynamic, static and rigidity characteristics of the pneumatic muscles. This paper chooses the pneumatic muscles on the basis of the parameters of the designed robot and studies the characteristics of the pneumatic muscles theoretically and experimentally.Thirdly, this paper studies the control strategy of the designed biped robot. The walking trajectory of the biped robot is planned through ZMP method, through which the desired joint angle and position of ZMP point are got. The joint angle of the biped robot is controlled through PID controller and the angle of the ankle joint is controlled through fuzzy control. The walking of the designed robot is controlled through this double-closed-loop control system.Finally, the robot prototype is made. The walking of the biped robot is controlled by the method put forward by this paper. During the process of the walking, the position of ZMP point and the angle of every joint are got through related sensors. The result of the 2D walking experiment shows that the ZMP point of the biped robot always stays in the contact area of foot and ground and the angle of every joint is similar to the related joint of humanbeings. It is proved that the designed biped robot can walk stably and the design meets the requirements.