High Precision Redundant Robot With Rope Drive And Its Compliance Control Method

The redundant rope drive robot with the characteristics of mechanical electrical separation and large aspect ratio is used more and more in the narrow space environment,such as space satellite internal maintenance,nuclear power plant pipeline detection,etc.,but the poor motion accuracy in the semi closed loop control and the lack of rich control methods greatly limit its use scope and effect.In this paper,aiming at the practical problems in the use of rope drive robot,we will develop a high-precision redundant rope drive robot,study its control method,and provide an expandable experimental platform for the follow-up research on rope drive robot.In order to meet the needs of maintenance,assembly and other fine operations in a narrow space,a high-precision redundant robot system with rope drive is proposed.The robot adopts modular design,which is composed of boom and d rive box with 8 degrees of freedom.The drive control box is integrated with electric driver and tension sensor.The modular center block is equipped with split measurement angle encoder and multi-level measurement angle encoder The sensor guarantees high precision negative feedback control.On the basis of robot structure design,the position level and speed level kinematics model of "motor rope joint end" multi space mapping of rope drive redundant robot is established,the inverse kinematics solution equ ation is derived,the inverse kinematics solution flow based on Jacobian pseudo inverse and Jacobian velocity level is designed,and the straight line and arc trajectory planning program is compiled,and the calculation result table is shown The method bas ed on Jacobian pseudo inverse is faster.In this paper,the statics model of redundant robot driven by rope is established by Newton Euler method,and a method of error optimization inverse solution is put forward,which can better predict the angle of cardan joint through the length of rope.A hybrid control method based on position compensation is proposed to compensate the length change caused by the force change of rope In the force position hybrid control loop,this method can make the rope drive robot better adapt to the environment such as oil pollution radiation and higher control efficiency.The mobility control method is introduced into the rope drive robot,and the robot control system is developed.A prototype robot is developed and a complete robot system is integrated.Based on the system,performance tests such as trajectory planning,repetitive accuracy,force position hybrid control experiments and mobility control experiments are carried out.The experimental results show that the design of robot system reaches the design target,and its control method is reasonable and effective.