Research On Trajectory Planning And Optimization Of Automatic Loading And Unloading Hydraulic Cylinder For Continuous Casting Ladle Robot

With the rapid development of informationization and intelligence in the steel industry,the unmanned factory has become an important direction for the development of intelligent manufacturing.Using robots instead of manual handling to load and unload ladle hydraulic cylinder can reduce production risks and improve production efficiency.In this dissertation,the path planning,trajectory planning and multi-objective trajectory optimization of the 6-DOF continuous casting ladle robot in Tanggang new factory are studied.The main research content of this dissertation is as follows:Firstly,this dissertation focuses on the modeling problem of continuous casting ladle robots based on the principles of pose description and coordinate transformation.According to the specific model of the continuous casting ladle robot,the linkage model of the robot is established by using the D-H parameter method,and the forward kinematics and inverse kinematics of the robot are analyzed.Secondly,aiming at the path planning of the continuous casting ladle robot,according to the actual situation of the factory,the robot is enveloped by the cylindrical envelope method,and the obstacle is enveloped by the envelope ball in the envelope box detection method.Based on this,the collision detection analysis of the robot is carried out.Based on the collision detection analysis,the path planning of the continuous casting ladle robot is carried out based on the improved RRT* algorithm,and the simulation experiment is carried out in MATLAB.Secondly,for the path planning of the continuous casting ladle robot,this dissertation considers the actual situation of the factory to analyze the obstacle detection model for the robot.The robot is enveloped by the cylindrical envelope method,and the obstacles are enveloped by the envelope ball in the envelope box detection method.Based on the obstacle detection model analysis,the path planning of the continuous casting ladle robot is carried out based on the improved RRT* algorithm,and the simulation experiment is carried out in MATLAB.Then,for the trajectory planning of the continuous casting ladle robot,this dissertation chooses to carry out trajectory planning in joint space.The basis function of the quintic B-spline function is constructed,and the control points of the quintic B-spline function are constructed using the discrete path points obtained from the path planning.Based on quintic B-spline curves,the trajectory planning simulation experiments of the continuous casting ladle robot are carried out in MATLAB.Finally,for the multi-objective optimization of the robot trajectory,this dissertation improves NSGA-Ⅱ algorithm based on two-dimensional chaotic mapping initialization.The improved NSGA-Ⅱ algorithm is used for multi-objective optimization of the trajectory.In this dissertation,combining the task requirements of the continuous casting ladle robot and the overload problems that occurred during the commissioning process,time and jerk are selected as optimization objectives.Kinematic constraints of the robot regarding velocity,acceleration and jerk are considered.Simulation experiments are conducted in MATLAB to obtain the pareto frontier of NSGA-Ⅱ,and suitable solutions are selected and applied to the B-spline curves to obtain the optimized trajectory curves.