Research On Robot-Assisted Gasbag Bolishing Under An Unknown Environment

In order to realize the function of the robot-assisted gasbag polishing system can automatically identify and obtain the geometric information of the polished workpiece, one algorithm was proposed which enable the robot-assisted gasbag polishing system can reconstruct surface of the polished workpiece under an unknown external environment, it is a surface fitting algorithm based on least square method. To achieve this function, the processing efficiency of the gasbag polishing was improved, and the technical requirement to the operator was reduced, but also to adapt to the characteristics of modern manufacturing industry product. In addition, in order to solve the problem of active compliance control between the polishing tool and workpiece, one force control system was presented which base on the passive structure of the air sac head, so as to ensure the precise requirements in the process of polishing system on the position and contact force, and ensure the surface quality of workpieces to be machined. The study of the above two problems are hot topics in the field of robot, which has important significance to the robot-assisted gasbag polishing system.First of all, the description method of position and the kinematic equations of industrial robot AS-5DOF were discussed and the representation of forward and inverse solution also were provided; secondly, the method of online reconfiguration polishing workpiece CAD geometry information and a force control system based on air sac polishing head structure of the active passive compliant which is to ensure the gasbag polishing force control precision were proposed; then, the software modules of the gasbag polishing system were introduced briefly; finally, an experimental platform which can rebuild an unknown workpiece was built, and verified by this experiment. The main research contents and results are as follows:1. Starting from the basis of the robot kinematics, analyzing the kinematics of industrial robot AS-5DOF comprehensively, discussing the method to describe the position and pose of the robot, building the robot kinematics equation, then combined with the structure parameters and joint variables of the industrial robot’s each bar, finding out the forward and inverse solution of the manipulator kinematics equation.2. By using the predetermined force tracking control system to compensate the position and the mapping relationship of the forward manipulator kinematics, finding out the forward solution of the manipulator kinematics equation, and obtaining the coordinates of the vertices of surface polishing value of each point. Then based on these values, we fit the curve segments and get the reconstructed geometry information of the workpiece with the least square method.3. In order to make the end of the polishing robot remains expected contact force and precision of position in constrained environment movement, proposing an active passive compliant force control system which based on the passive structure of the gasbag polishing head. It is an outer loop force control based on inner position loop, can achieve force control with not changing the robot internal position controller.4. By using Visual C++as the platform, developing the control software of the gasbag polishing system, thus the gasbag polishing system increases the function of online reconstruction workpiece CAD information and outer loop force control algorithm based on robot internal position loop.5. An experimental platform which can rebuild an unknown workpiece was built, and the hardware&software design scheme of the experimental system are discussed in detail, and achieve the desired results by the related experiments.