| With the development of contemporary social economy and the improvement of modern industrial level,the independent operation of traditional legged legged robots and fixed base robotic arms has been unable to meet the needs of modern industrial production and special operation scenes.Therefore,the robot arm is installed on the legged legged robot,and the flexibility of the legged legged robot and the maneuverability of the robot arm are fully utilized to complete complex tasks in special scenarios,which has a wide range of application prospects.This paper takes a quadruped robot loaded with two arms as the research object,conducts kinematics modeling and analysis,control system design,single-leg compliant control,and research on zero-space-based collaborative operation of legs and arms.Specific work contents are as follows:(1)For the leg layout and kinematic modeling of the robot,the double-elbow leg layout with more stable structure is adopted;The D-H method is used to establish the coordinate system,the forward and inverse kinematics equations and the Jacobian matrix are derived,and the four-legged working space is calculated.Aiming at the layout and kinematics modeling of the manipulator,the characteristics of the front and back layout and the left and right layout of the arms are analyzed.The front and back staggered layout with larger working space and more uniform distribution of center of gravity is adopted.The coordinate system is established by D-H method,the forward and inverse kinematics equations are derived,and the working space of both arms is calculated.(2)Aiming at the single-leg active compliance control,the hydraulic cylinder model is established,and the two-cylinder jacking experiment based on the segmented PID control is carried out.The mapping relationship between cylinder length and joint Angle,between cylinder force and joint torque was deduced.The dynamic modeling of single leg was carried out.A single leg active compliance control method based on the spring-damping virtual model was designed,and the joint torque was controlled only considering the gravity compensation.Finally,a single leg compliance experiment was conducted to analyze the response of the single leg platform,and the feasibility of the active compliance control method based on the spring-damping model was verified.(3)In view of the need to realize the cooperative work of quadruped two-arm multi-limb robots,the overall architecture of distributed real-time measurement and control network is designed,the control system based on the distributed structure of CAN bus is built,the main program and various subroutines of the main controller are written,and the multi-core and multi-threaded technologies are adopted to realize the parallel operation between different tasks.The real-time performance and reliability of the system are improved,and the corresponding data encapsulation and data analysis are realized when CAN communication sends and receives data.The service program of servo controller is written and the joint servo control of manipulator is realized.At the same time,in order to facilitate the analysis of experimental data,the offline analysis software of robot leg movement data and the offline analysis software of robot arm movement data are designed respectively.Finally,in order to ensure the normal operation of the robot,the calibration method of sensor and encoder is designed.(4)Aiming at the multi-task motion of army-foot cooperation,the multi-task motion planning method based on null space mapping is introduced,and the multi-task analysis of army-foot cooperation is carried out based on this method.A whole-body control framework based on null space mapping was designed to map the torso motion to the null space of the manipulator motion task for control.The multi-task task is divided into priority,and the trunk motion task is mapped to the null space of the manipulator motion task,so as to ensure the execution of the manipulator motion task.The virtual prototype simulation experiment is carried out to verify the feasibility of the foot and arm cooperative control method based on the null space mapping. |
