The Deverlopment Of Industrial Rotot System Based On General-purpose Motion Controller

The openness and expandability of the dedicated controller for industrial robots are insufficient to cope with the customed development of complex and precise tasks.The general-purpose motion controller has been widly used in the field of motion control due to its standard,open and easy to develop features.So in this dissertation,the technical features of the general-purpose motion controller is systematically studied and the development of the industrial robot system based on the general-purpose controller is carried out for friction stir welding.The general-purpose motion controller is composed of soft PLC based on IEC61131-3 standard and real-time industrial Ethernet which can meet the openness and real-time requirements of industrial robots.First of all,the development approach of robotic application software on standard soft PLC is analyzed.Then,according to the layered bottom-up architecture of the robotic system,the different functions are developed in the form of modules which include basic functional modules and extended functional modules.The basic function modules included fieldbus intermediate layer interface,single-axis and multi-axis motion function blocks based on the PLCopen standard,6-DOF industrial robot kinematics and inverse kinematics modules,trajectory planning function blocks of straight lines and circular arcs,etc.The extended function modules are as follows:1)Double S velocity profile algorithm.In order to improve the smoothness and accuracy of the terminal trajectory,the double S velocity profile algorithm function block is developed for the interpolation operation to make its acceleration curve meet the continuity requirements.2)Cubic B-spline trajectory planning module.The cubic B-spline trajectory planning method is proposed which can fit terminal trajectory by teaching the key points on the trajectory.Taylor series is used to interpolate parameter u of the spline curve and the terminal linear velocity meets the double S velocity profile.3)Intelligent perception interface module.The intelligent perception interface is designed to realize the interaction between the robot and the environment in complex operatons.The force control between the robot and the environment was achieved by force sensor combined with the variable impedance control algorithm.The visual sensor combined with the cubic B-spline curve trajectory planning method is used to implement the visual aided teaching function.Finally,the customed development and application is conducted through the simulation experiment of industrial robot friction stir welding.In the experiment,weld joint trajectory is generated by the image grabbed by the visual sensor and the contact force can overcome the the disturbance and maintain a constant value through force sensor combined with variable impedance control algorithm.The experiment results of correctness and feasibility of each module and the overall architecture of the industrial robot developed on the general-purpose motion controller.The robot system can fulfill the demand of customized development tasks in complex and precise works.