| Industrial robots are now widely used in abrasive belt grinding operations,but the mode of teaching and reproduction is still mainly used to produce robot grinding trajectory.Once the shape of the surface is complex,the teaching programming is not only time-consuming but also reduces the quality of robot grinding.In order to using off-line programming mode to fastly produce high quality robot grinding trajectory,the tool path planning,robot grinding trajectory planning and robot grinding trajectory optimization are studied.In order to generate high-quality surface grinding tool locations,surface grinding tool path generation method and interpolation method were studied.In order to solve the problem of sharp curvature of the curve,the number of tool locations generated by the algorithm of curvature estimation interpolation is too sparse,an optimized algorithm of curve interpolation is proposed.The number of the tool locations generated by this algorithm would conform to the setting error in any place of the curve,avoiding the occurrence of over cutting.In order to solve the boundary problems and self-intersection problems generated by offset line iso-scallop tool path generation method,an iso-scallop path algorithm based on parametric line method is proposed,compared with the traditional offset line method,the algorithm is more stable,and there is no boundary problem and self-intersection problem.The simulation results show that the tool locations generated by the algorithm above has high quality and can meet the requirements of grinding.In order to transform the surface grinding tool locations into the robot grinding trajectory,the robot grinding trajectory planning method is studied.In order to improve the universality of the robot grinding trajectory planning algorithm,the screw theory is used to model the positive kinematics of the robot,and the numerical method is used to solve the robot inverse kinematics problem,compared with the forward and inverse kinematics equations established by the D-H parameter method,the modeling method has a unified solution for different types of robots,and a universal algorithm for solving the forward and inverse kinematics of the robot is realized.Then,the principle of generating the robot grinding trajectory based on tool location file is expounded.The simulation results show that the modeling method has good generality,and the robot grinding trajectory generated by the above modeling method is consistent with the grinding trajectory of the robot modeled by D-H parameters.The robot trajectory,generated by the above robot grinding trajectory planning method,may have some defects such as larger joint volume and collision in grinding process.To solve this problem,an optimizing robot grinding trajectory searching algorithm is proposed.First,it is proposed that we can adjust the grinding path of the robot by adjusting the location of the grinding point on the belt wheel.Then,the adjustment formula of grinding point coordinate system is derived and integrated;according to the adjustment formula of the grinding point coordinate system,establishing a mathematical model that using two coordinate axes to describe the robot grinding trajectory.Finally,a robot searching algorithm is proposed to get a collision free robot with small joint size.The algorithm is simulated with V-shaped workpiece,compare and optimize the robot trajectory obtained from the pre robot polishing trajectory planning algorithm,the maximum joint change of robot trajectory obtained from optimization algorithm is reduced from 2.8123 rad to 1.0741 rad.Then the S-shaped workpiece is used to simulate the algorithm,which shows that a collision free robot grinding path can be generated by the optimization algorithm,and the collision free robot belt grinding can be achieved. |
PDF Full Text Request