| Different from the traditional single-arm robot,the two-arm cooperative robot system has the advantage of cooperation and mutual assistance between the two robotic manipulators,and can complete the complex operation tasks assigned by the two robots.It has become one of the hot issues in the field of robotics research.In this paper,safety trajectory planning and the improved sliding mode impedance control are studied as follows,and laboratory equipment is used to complete the experimental verification of dual-arm coordinated handling operation.Firstly,the specifications and space configuration of the 6-DOF Kinova Jaco2manipulator model are analyzed,and the kinematics model is established with a single manipulator as the research object.Then,the end-effector homogeneous transformation matrix of the dual-arm cooperative robot is obtained according to the base transformation relationship,and the joint kinematics equation of the dual-arm robot is established.It lays the foundation for the following research on trajectory optimization and sliding mode impedance control algorithm of dual-arm cooperative robot.Secondly,in order to solve the safety problem between the robot arm and the environmental obstacles in the process of moving,a method of tracking the robot end-effector trajectory based on null space obstacle avoidance is proposed.After completing the hyperquadric modeling of environmental obstacles,a method to calculate the minimum pseudo-distance between the obstacle model and the manipulator links is presented,and the null space obstacle avoidance problem of the manipulator is solved by combining the gradient projection method.The adaptive positive definite coefficient matrix K pm（t）and error saturation function sat（ηe）in the proposed motion algorithm feedback the real-time trajectory results to the inverse kinematics solution of the manipulator,and adjust the angular velocity of the joint adaptively according to the feedback results to reduce the trajectory tracking error of the end-effector.The feasibility and superiority of the proposed trajectory optimization method are verified by comparing with the traditional obstacle avoidance algorithm and the end-effector trajectory tracking strategy.Then,dual-arm cooperative control algorithm based on improved sliding mode impedance controller is proposed to meet the requirements of high-precision force/position control for carrying objects by dual-arm robot.First of all,set up dynamics equations combined with the unity of the target object,and then,according to the target object oriented motion model of the impedance control the desired joint angular acceleration,the introduction of improved hyperbolic tangent function as the switch function of the sliding mode controller,the method of impedance control and improve the method of sliding mode control,get arms coordinated control strategy based on improved sliding mode impedance controller.Finally,the simulation experiments of PD,SMC（sign）and MSMIC（tanh）for sine function curve tracking and dual-arm coordinated moving are completed to achieve stable joint control torque and high-precision trajectory tracking.Finally,the two same 6-DOF Kinova Jaco2 robots are used to build a dual-arm cooperative robot system to verify the proposed dual-arm coordinated handling control strategy.The dual-arm robot environment is configured in the plug-in Move It!in ROS system,the RViz tool is used to visualize the motion process,and the coordinated handling operation of the dual-arm robot is realized through the program language.The effectiveness and superiority of the dual-arm robot coordinated handling control strategy are verified. |
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