Design And Control Of Wheel Legged Quadruped Robot Based On 6R Manipulator

With the development of mechanical science and electronic control technology,more and more robots are used in industrial production and daily life.As a kind of bionic robots,wheel-legged quadruped robots have the strong advantages of the obstacle-crossing ability,fast movement and the environmental adaptability,which make them gradually emerge in various fields of production and life.In the 1980s,Europe,the United States,Japan and other countries conducted the research on related theories and technologies,which embraced in military,aerospace and other fields.Therefore,the study of wheel-legged quadruped robots has significant value in theoretical and practical application.In this research,based on the 6R six-degree-freedom robotic arm,we analyzed and designed the structure,kinematics/dynamics,and wheel/foot control system of the single-leg wheel-legged quadruped robot,which the work and research results are organized as follows:(1)Structural design of wheeled legged quadruped robot.According to the task requirements,the structure of each part of the robot body is designed,and the key structure of the robot is checked.(2)Modeling and analysis of wheeled legged quadruped robot.Firstly,the body and single-leg coordinate system of the wheel-legged robot are established,and the single-leg kinematics model is established.Then,the motion configurations of the robot are designed and the statics analysis is carried out to verify the reliability of the configuration.Finally,the singleleg dynamics model is simplified and the dynamic equations are solved by Lagrange method.(3)Foot motion control system design.Firstly,all kinds of gait stability and movement rules of foot movement are analyzed,and zero impact trajectory curve of foot is designed.Then,in view of the complexity of the original single-leg dynamic model and the large amount of calculation,a single-leg three-joint robust adaptive foot position tracking system is designed based on the simplified dynamic model,and its tracking effect is simulated.Finally,the typical gait of foot movement is selected for joint simulation of foot movement of wheel-legged robot.(4)Wheel motion control system design.Aiming at the problem that the turning radius of the traditional kinematics model is too large to track the complex traj ectory,a four-wheel differential steering kinematics model based on all-wheel steering is proposed,and the model predictive control algorithm is used to track the trajectory accurately.Then,in order to solve the problems such as abrupt change of leg end force,movement trajectory deviation and attitude instability caused by terrain changes in obstacle crossing,the original variable stiffness position impedance control method is improved,and the variable stiffness position adaptive impedance control method based on fuzzy controller is proposed.Finally,the effectiveness of the proposed method is verified by joint simulation.