Configuration Design And Trajectory Planning Of A Robot For Multi-chamber Workpiece Spraying

In the industrial production,the spraying operation is an important machining process,and the spraying robot has been widely used in the spraying industry,but the spraying task on the inner surface of the complex workpiece also depends on the manual finishing.The main content of this paper is to spray the inner wall of a large-scale component with multichamber multi-obstacle,so a new type of spraying robot is designed,and the control algorithm is designed according to the requirements of the surface spraying operation in the cavity wall.Firstly,according to the structural characteristics of the multi-chamber and multiobstacle large components,the robot structure is divided into three parts according to the function: the work positioning device,the work execution device and the auxiliary support device,which are designed separately.The mathematical model of the nine-degree-offreedom robot is established by using the DH parameter method,and the positive solution is obtained according to the established mathematical model.Considering that the inverse solution of the nine-degree-of-freedom robot is too complex,a new inverse kinematics solution method is proposed.according to the characteristics of the workpiece and the requirements of the spray trajectory.The angle presupposition of the first three joints is carried out according to the cavity wall sprayed in different directions to ensure that the spray target plane is in the flexible workspace of the work execution device.According to the characteristics of joint 7 workspace,forward solution and inverse solution are used to get the position coordinates of joint 7 and the pose of joint 6 was inversely deduced,and then the inverse solution was completed by solving the angle values of other joints.The inverse solution obtained by this method can guarantee that the robot can have similar pose when spraying on the same wall.It solves the problem that the number of inverse solutions is too many,it is difficult to solve,and it is difficult to select,which greatly improves the solving speed of the inverse solution.Position interpolation is based on the combination of spatial linear interpolation and spatial circular interpolation.On the basis of homogeneous transformation and quaternion theory,the position is described by matrix,the attitude is described by unit quaternion,and the attitude is interpolated by spherical interpolation curve,and the position and pose of robot end-effector is expressed.In the way of speed control,the standard S-type velocity curve is adopted and modified.Velocity stationarity and acceleration performance are important indexes to evaluate the speed control curve.The common velocity control models are studied first.In the above performance,the standard S-type velocity curve has outstanding advantages.In view of the limitation of low adaptability of standard S-type velocity curve,the abnormal condition is preprocessed.Then two adaptive S-type velocity curve algorithms based on the given initial speed and running time are proposed,and the improved speed control algorithm is obtained.It not only retains the good performance of the standard S-type velocity curve,but also improves the compatibilities.