Research On Control Strategy Of Running Motion Of Quadrupedal Robot

Movement speed is an important indicator for measuring the performance of a quadrupedal robot.To improve the movement speed,the running of the robot must be studied.At present,most researches on a quadrupedal robot in China still focus on stability and carrying capacity,and the related control strategies are mainly open-loop control or stability control.Given this situation,it is of great significance to study the control strategy of the running motion of the quadrupedal robot.The research purpose of this paper is to propose a strategy for controlling the running motion of a quadrupedal robot,so that the robot can run stably and quickly.With reference to the running of quadrupedal animals,a corresponding gait generator is proposed in this paper,and completes the modeling,analysis,and control of the quadrupedal robot.Finally,the viability of the control strategy is demonstrated using simulation experiments,and the experimental results are analyzed.The main research methods and research contents are as follows:(1)A gait generator based on the Central Pattern Generator(CPG)is used,and the four legs of the robot are controlled by four Hopf harmonic oscillators with different phases.The CPG signal is used as the driving signal of the foot-end trajectory,and the influence of its key parameters on the movement of the quadrupedal robot is analyzed.(2)A quadrupedal robot is modeled and the one-leg kinematics is analyzed.Based on the Sagittal Plane Model,the motion law of the robot when running in bounding gait is studied,and a method of calculating the theoretical foot-end force is proposed according to the dynamic equation.Also,the foot-end trajectory of the robot is planned.(3)According to the principle of impedance control,a method for detecting touch-down events is proposed.In terms of control,the control strategy based on Cartesian space is adopted,and the torque of the joint motor is adjusted by adjusting the virtual force at the foot end,to control the running of the quadrupedal robot.(4)Through the combined simulation of Adams and MATLAB,the control strategy used is verified.The stability of the robot running is verified in the experiment,and the results of foot-end trajectory tracking control,body height control,body pitch angle control,and running speed control are analyzed.Finally,the changes in foot-end force and joint torque are explained.After the research of this article,the quadrupedal robot realizes the stable running with bounding gait,the body height can reach 0.43 m,and the body pitch angle is controlled at-11.46°?14.32°.The maximum running speed is 2.21 m/s,which has reached the target of high-speed movement.