Research On Compliant Grabbing And Assembly System Based On Binocular Vision And Six-Dimensional Force Control

With the improvement of automation level in industrial production,higher requirements are put forward for the intellectualization and flexibility of the system.Industrial robots are widely used in industrial production because of their stable motion and high repeat positioning accuracy.Traditional industrial robots are operated by teaching programming,which is unable to automatically adjust the motion trajectory in response to environmental changes.The multi-dimensional and flexible characteristics of robots cannot be fully utilized.In order to solve the requirements of robotic grabbing and assembling tasks,this paper combines industrial robot with camera and force sensor.Based on the binocular vision technology,the robot is guided to capture the arbitrary position of the space.The pose adjustment of robot assembly process based on force control technology is studied.The grasping and assembly experiment platform is built to realize the grasping of workpiece in space and the flexible assembly of axle hole.In this paper,the linear imaging model of the camera and the principle of binocular vision is studied.A mathematical model of the correspondence between the camera coordinate system and the spatial point is established.Through camera calibration and hand-eye calibration,the numerical correspondence between the spatial point and the camera,the camera and the robot are established.The image collected by binocular vision system is preprocessed and corrected to reduce the influence of system noise and equipment position error.The principle and method of stereo matching are studied,and the region-based stereo matching algorithm is used and optimized to obtain the matching points of image pairs.The matching points are reconstructed according to the 3D reconstruction principle,and the 3D information of workpiece surface is obtained.According to the characteristics of the workpiece,the spatial pose of the workpiece is estimated,and the spatial pose of the workpiece relative to the camera is obtained.Aiming at the communication problem of force sensor and the influence of gravity on the measured data,a force sensor communication system and a gravity compensation system are designed.Accurate measurement of the contact force between the robot end and the environment is realized.The axial hole assembly is analyzed and simulated,and the stress of each stage of axial hole assembly is obtained.The control algorithm is studied.The impedance control algorithm based on position is improved and the error of impedance control is analyzed.Impedance control and adaptive impedance control are compared by simulation.The secondary development of ABB robot is carried out,and software is written to realize real-time control of robot movement.The grasping and assembly experiment platform is set up to carry out the verification experiment.The hardware,software and communication system of the system are designed and built.The feasibility of the system is verified by the completion of the visual guided robot grasping experiment,the machine manual following teaching experiment and the axle hole compliant assembly experiment.