Force/Position Hybrid Control Of Manipulator Based On Six Dimensional Force Sensor At The End And Its Application

At present,the first generation of industrial robots widely used in the industrial production process can complete handling,welding,spraying and other work,but there are many technical difficulties in upgrading to the second generation of industrial robots.A typical problem is to install a six-dimensional force sensor at the end of the first generation of industrial robots to make it have force sense,so as to make the end of the robot maintain the expected force in the specified direction,and maintain the expected position in the other direction,that is called force/position hybrid control.Aiming at the first generation of industrial robots widely used in industrial field,this paper upgrades the robot control system on the base of summarizing the existing research results at home and abroad,designs and improves the force/position hybrid control scheme of the manipulator,and carries out experimental verification on the scheme based on the existing experimental conditions.In order to improve the performance of the hybrid force/position control,it is necessary to use the dynamic model of the manipulator in the control strategy.As the basis of manipulator dynamic control,the parameter identification of manipulator dynamic model is the first step.This paper refers to the domestic and foreign research on the dynamic model parameter identification of manipulator,and simplify it,so that it is more suitable for rapid application in industrial field,and carry out experimental verification on the HAN'S robot.Implicit force control needs to obtain the end trajectory according to the force error of Cartesian space,and then use the inverse kinematics solution to obtain the target position in joint space for control.Therefore,the position servo strategy has higher requirements:faster response speed and smaller trajectory tracking error to ensure the stability of force control.Adapt to different joint configurations to ensure no oscillation at all.In this paper,based on the joint space dynamic model,a joint independent control strategy based on the extended state observer and torque feedforward is proposed,which is suitable for the current mainstream servo control scheme in which each joint is mutually independent.The algorithm has been verified by experiments on HAN'S robot.Based on the linearized joint space control scheme,the force control in Cartesian space is realized by using the information of the six-dimensional force sensor as feedback.In order to improve the stability and rapidity in contact with the working environment,the force servo scheme that the joint independent control algorithm based on the extended state observer and torque feedforward as the position control inner loop,and the damping control as the force control outer loop is proposed.The force servo scheme is verified by experiments on HAN'S robot.After the position control and force control of the Cartesian space are solved,the force/position hybrid control can be realized only by adopting the corresponding control strategies in all directions of the Cartesian space.Based on the position control and force control schemes,the hybrid impedance is adopted as the force/position hybrid control scheme.Finally,the hybrid control scheme is tested in two typical application scenarios:drag demonstrating and rough surface tracking,and it is verified by experiments on HAN'S robot.The results show that the proposed control scheme meets the performance requirements of force/position hybrid control.