Research On Pose Planning Algorithm Of Six-axis Robot Based On LinuxCNC

With the improvement of the automation degree of China's manufacturing industry,a lot of physical and repetitive labor will be replaced by industrial robots in the future,and the demand for industrial robots in the manufacturing industry is increasing.When performing industrial tasks,the industrial robot needs to ensure that the position and orientation of the end effector meet the mission requirements.Therefore,research on pose planning can improve the motion accuracy of industrial robot end actuators.This thesis studies the pose planning of the end joints,and the algorithm will be implemented on LinuxCNC.Firstly,in order to describe the kinematic relationship between the pose of the end joint and the joint angle of the robot,this thesis uses D-H method to establish the kinematics model of the six-axis robot.In the solution of inverse kinematics,the pose separation method is used to simplify the calculation,solving joint angle with quaternions.Secondly,when processing complex curves,NURBS is often used as the trajectory of the robot end effector.However,the calculation of its interpolation parameters will affect the smoothness of the curve.In order to improve the computational efficiency of interpolation parameters,an iterative algorithm for interpolation parameters is proposed.In order to reduce the interpolation error during processing,this paper controls the interpolation step by controlling the interpolation speed.A speed planning algorithm using pre-interpolation to identify features of curves is proposed.By this way,the bow height error is effectively reduced.Thirdly,the quaternion is an effective way to describe orientation,which is abstract and difficult to understand by engineers.Therefore,this thesis uses spherical projection to study the rotation effect of quaternion on vector.Because constant parameter interpolation will cause a sudden change in angular velocity,the iterative method is used to calculate the interpolation parameters based on the angular velocity,which avoids the sudden change of angular velocity.Since the orientation motion and the position motion need to be synchronized in time,a cooperative angular velocity planning algorithm is proposed,which enables the robot to complete the orientation motion under time-constrained conditions.Finally,as an open source CNC software,LinuxCNC is beneficial for engineers to develop and meet specific production needs.This thesis introduces a six-axis robot control system with LinuxCNC as the controller.According to the LinuxCNC programming method,the above algorithm is implemented and tested on LinuxCNC.In order to make the experiment more intuitive,the 3D simulation model and control interface of the robot were established.The experimental results show that the 3D model can complete the desired position and orientation motion according to the instructions,which proves the effectiveness of the pose planning algorithm.