Calibration And Trajectory Planning Of A Hybrid Spraying Robot

The spraying robot is an automatic equipment that is widely used in automotive painting production lines which greatly improves the quality and efficiency of automotive body spraying.The spraying robot accuracy,the spray trajectory,the shape of the surface to be sprayed,and the process parameters of the spray gun both directly affect the spraying quality.In order to improve the spraying quality,this paper takes a selfdeveloped fixed six-degree-of-freedom hybrid spray robot as the research object,investigates error modeling,parameter identification,data measurement and other key processes of kinematic calibration technology,and proposes a kinematic calibration method.After ensuring the motion accuracy of the robot,this paper optimizes the process parameters by studying the paint distribution under different spray trajectories,and proposes a trajectory planning method to ensure uniform coating thickness.The specific research contents are as follows:Based on the self-developed hybrid spray robot,the kinematic model of the robot is analyzed by structural equivalent method.And on this basis,the error model and identification model of the robot is established.Aiming at the problem of strong coupling of error parameters,a method of eliminating redundant error parameters through vector stacking is proposed.Due to the small curvature of the car body,the position accuracy of the robot is more important than the attitude accuracy.Therefore,this paper analyzes the feasibility of the partial freedom measurement of the robot terminal,studies the influence of the lack of terminal attitude measurement data on the accuracy of the terminal position,and proposes a robot terminal position measurement scheme based on the laser tracker.In addition,in the aspect of identification algorithm,this paper proposes a fast selection method of ridge estimation algorithm parameters,and compares the ridge estimation algorithm and the least squares identification performance.Then,combined with the control strategy of the robot control system,an error compensation scheme based on trajectory compensation is proposed.In addition to the accuracy of the spray robot,the spray trajectory is another important factor that affects the spraying quality.In this paper,the coating deposition model of fixed-point spray,single track spray and reciprocating spray on plane and free-form surface was established.The optimization method of spray track parameters was proposed and verified by simulation.The simulation results show that the spray trajectory planning by this method can greatly improve the spraying quality.In order to verify the calibration compensation effect,the hybrid painting robot was calibrated under the all-motor driving condition.Based on the experimental results,the possible structural problems of the robot were inferred.The above inference was verified by the calibration experiment under the condition of partial-motors driving.Finally,a third-party testing agency is invited to perform accuracy testing on the calibrated robot.The test results show that the kinematic calibration scheme proposed in this paper can effectively ensure the terminal output accuracy of the robot.