Research On Collision Detection And Reaction Of Industrial Robot Based On Model

With the increasing popularity of robots in industrial production,people put forward higher and higher requirements for the safety of robots.Aiming at the problem that robots are easy to collide with people or objects in their workspace,this paper presents a model-based collision detection and response method for industrial robots.The control system can detect and respond to collisions without additional sensors..The main work of this paper is as follows:Firstly,the dynamic model of the robot body is established by Lagrange method,and the load is taken as a part of the model.When the load changes,the whole dynamic model can be modified only by inputting load parameters.A parameter identification method of dynamic model based on experiment is designed,and the identification trajectory based on finite Fourier series is improved to improve the identification efficiency.Secondly,the types of collisions between industrial robots and the external environment are studied.For passive collision,the actual output moment of the robot joint is compared with the model-predicted output moment of the joint,so as to achieve the purpose of collision detection.For active collision,the collision detection method based on energy method is improved,so that the collision detection can meet the system requirements of rapidity and accuracy.Then the reaction of industrial robots after collision with external environment are studied,and the position control reaction and the force control reaction are proposed.According to the collision information detected during the collision,the former can plan the back path of the robot to cancel the contact force between the robot and the object being collided.The latter enables the robot to maintain a relatively stable contact force with the impacted object,and to change its position according to the change of contact force.An adaptive adjustment algorithm of damping coefficient based on fuzzy control is proposed,which can improve the flexibility of the robot to contact force.Finally,the control system of the robot is built on the industrial computer based on TwinCAT.The proposed algorithm is validated by an industrial computer,a six-axis force sensor and an ER30 industrial robot.The experimental results show that the control system can detect the collision between the robot and the outside environment without additional sensors,and make timely and reasonable response to avoid possible damage.