Design And Optimization Of High Energy Efficiency Mechanism For Electric Quadruped Robot

With the continuous development of robotics,legged robot has gradually become a hot research topic in recent years.Compared with wheeled and crawler robots,legged robots are more suitable for transportation,patrol,reconnaissance,search and rescue,exploration and other tasks in complex terrain,so they have more extensive application prospects.Compared with the hydraulic drive,the motor drive has the advantages of high energy efficiency,fast response,low noise,simple structure,high reliability and wide adaptability to the robot scale,so the electric quadruped robot has occupied the mainstream of legged robot research.However,due to the unreasonable leg structure design of common electric quadruped robot,the motor driving performance is poor,which reduces the power density and motion energy efficiency of the robot.In order to optimize this problem,this paper designs a link type electric leg with spring energy storage and a quadruped robot mechanism,which is optimized and verified by kinematics and dynamics analysis,virtual prototype simulation and physical experiments.The main contents are as follows:(1)This paper summarizes and compares the existing joint driving methods of quadruped robot,designs an all elbow electric driving quadruped robot,and designs a leg mechanism aiming at reducing the joint torque.The knee joint driving motor is placed on the top,a three-bar linkage mechanism is added between the knee joint and the driving motor,and the elastic elements are paralleled in the linkage mechanism,The output torque of the joint motor is optimized by changing the transmission of joint force,and the output energy of the motor in reverse rotation is applied to the forward rotation through the storage and release of elastic potential energy to optimize the energy consumption of the system.Finally,the kinematics model of the whole robot and the dynamic model of the single leg are given.(2)In this paper,the gait of quadruped robot is selected,and the foot trajectory is planned.Based on this,the joint angle,joint angular velocity and joint angular acceleration of quadruped robot are analyzed.Then,based on the kinematics analysis and inverse kinematics formula,the foot to ground contact force and joint torque of the robot are calculated.(3)In this paper,the link length and spring stiffness of the robot leg mechanism are determined and optimized.According to the force transfer relationship between the knee joint and the joint drive motor,the output torque of the motor is calculated,and the problem of excessive output torque of the motor is optimized.The energy model of the single leg system is established,and the optimization effect of the elastic elements on the energy consumption of the system is proved.(4)In this paper,the walking simulation of the whole quadruped robot and the swing trajectory simulation of one leg are carried out based on ADAMS platform,and the results of kinematics and mechanics analysis of the robot are verified.The physical prototype of single leg is integrated to verify the motion space and trajectory of single leg system;The squat up experiment of single leg prototype is carried out to prove that the leg mechanism can optimize the motor output torque.