Research On Robot Ankle Reflex Control For Upright Standing Push Recovery

The ankle joint of biped robot should not only have similar shape and torque to the human ankle,but also have similar buffering function and upright standing ability.In this thesis,the structure and control algorithm of the bipedal robot's ankle joint are designed.A series elastic actuator(SEA)is added to the ankle joint structure of biped robot,and one kind of control algorithm is designed based on the upright standing push recovery of human ankle joint.The contents of the study are as follows:(1)Based on the size and weight of the human foot,ankle and calf,the mechanical structure of the ankle joint of a bipedal robot with similar shape and similar weight is designed.A SEA is added to the structure of the biped robot's ankle joint,so that it has the function of buffering,and realizes the torque control and position control conveniently.(2)On the basis of structure design,the hardware and software platform of ankle joint control system is designed.The hardware platform uses photoelectric encoder to collect the rotation angle information of the ankle joint and motor,and takes STM32 as the main control panel to drive the motor.The software platform is carries out logical processing,including the two parts of the slave computer and the upper computer.They communicate with each other by WiFi.(3)Human body's upright standing experiments were conducted to analyze the principle of human's push recovery.A muscle-like reflex control algorithm is proposed based on the structure and control system design of the bipedal robot's ankle joint.The algorithm is two-level closed loop control,the outer layer is the muscle-like reflex control,and the inner layer is the torque control based on SEA.The muscle-like reflex control algorithm runs on the lower computer software platform.Through the fixed stiffness rotation experiment and the upright standing experiment on the ankle joint of the robot,it is proved that the muscle-like reflex control algorithm can achieve the push recovery effect similar to the human ankle joint.