Research On Motion Planning And Control Method Of Robot

Biped robot has become one of the most cutting-edge topics in the field of robot because its shape and structure are more simila r to human beings and easier to integrate into human society.As the most basic humanoid behavior,the stable walking of biped robot has a very broad prospect,so it has attracted the attention of many international scholars and high-tech enterprises.Because of its high degree of freedom,complex mechanical structure and high coupling characteristics,it is a hot and difficult point for biped robot to realize smooth and stable walking.The research on the control of walking stability can not only help people understand the walking mode of bipedal structure more deeply,but also make robot serve human better.Therefore,the research of this topic has important theoretical significance and practical application value.Gait planning is to let the biped robot achieve the ideal trajectory of the center of mass,the swing leg and its own joints,and the walking stability control is to adjust the previously planned gait according to the walking state of the biped robot,so that the biped robot can maintain better stability in the walking process.Based on the collection and analysis of relevant data and experimental data,this paper focuses on the gait optimization and walking stability of biped robot(1)Kinematics model and stability judgment of Biped RobotAccording to the leg joints of the biped robot,the link model,the world coordinate system and the local coordinate system of each link are established.Based on the model structure of the robot,the forward and inverse kinematics model of the biped robot is established according to the geometric relationship between the joint and the connecting rod.According to the expression of ZMP(zero moment point),this paper judges the walking stability of biped robot.(2)Gait optimization based on particle swarm optimizationThe traditional gait planning not only makes the gait order of biped robot higher,but also makes the ZMP stability margin smaller.In view of the above problems,this paper uses particle swarm optimization method to optimize gait.In this paper,co mbined with human walking requirements,we use cubic spline method for gait planning.According to the starting position,the highest point and the stop position of the swinging leg of the biped robot,the gait of the robot in each walking cycle is planned.In the optimization phase of PSO algorithm,according to the distance from ZMP to the center of stable region as the judgment basis,the evaluation function of gait stability is constructed.PSO algorithm helps to search the parameters of trajectory pla nning,such as step size,double leg support period,single leg support period,and the optimal solution is calculated to make the ZMP of gait as close to the center of stable region as possible.(3)Walking stability control based on joint angle correctionIn the walking process of biped robot,due to the insufficient plantar friction and the joint angle error caused by the joint angle friction,the trajectory of the center of mass of the robot is deviated,which leads to the error of ZMP and has a great impact on the stability of walking.If only the joint angles of the supporting leg are compensated,the ideal walking control effect can not be achieved.To solve the above problems,this paper uses a method based on the correction of each joint angle for walking stability control.According to the position error between the landing foot and the planned landing foot,this method adjusts the trajectory of the swing leg in the next walking cycle,and finally corrects the desired joint angle according to the reconstructed trajectory.