Research And Implementation Of Quadruped Robot Stable Movement Method

As an indispensable branch of the field of bionic robots,legged robots have strong adaptability to complex environments.In recent years,the hydraulic quadruped robot developed by Boston Dynamic has attracted the attention of a large number of experts and scholars at home and abroad due to its excellent motion performance.However,due to the time-varying and strong coupling characteristics of the hydraulic quadruped robot,the corresponding motion control method is very complicated.In order to make the robot run stably and reliably under complex road conditions,this paper relies on the National 863 Program topic "Research and Development of Practical Technology for Quadruped Bionic Robots Facing the Field Environment" to study the control method of the stable motion of hydraulic quadruped robots.The main research contents are as follows:(1)Aiming at the design of the real-time control system of the robot,the controller and the real-time operating system are selected in accordance with the principles of stability,reliability and strong real-time performance.In order to expand the peripheral functions of the controller,select analog input,analog output,serial communication,CAN communication board.In the development process,multi-thread technology is used to improve the real-time and reliability of the system.(2)Aiming at the motion control of the robot's legs,a single-leg motion test system is built,and the D-H coordinate transformation method is used to perform positive kinematics analysis and derive the corresponding inverse kinematics equations.Through a simplified analysis of the hydraulic actuator,the output force of the actuator is mathematically modeled,and the mapping relationship between the output force and the signal current is established.The impact test of the robot single leg in position control,impedance control and virtual model control was carried out,which improved the control strategy of the robot leg and reduced the impact of the ground contact on the leg structure.(3)Build a simulated robot in the robot simulation environment Webots.By introducing the posture angle of the torso and its differential terms into the control closed loop during the movement,the dynamic adjustment of the leg movements is performed to maintain the stable movement of the torso.For the control of the legs during exercise,the virtual model control method is adopted according to the experimental results of the single-leg test platform.According to the error between the expected foot position and the foot position obtained by the feedback and its differential terms,the virtual force of the leg is calculated by the virtual model,and the output force of the leg is controlled by the joint torque control of the robot leg to improve the adaptability of the robot to the environment.