| The velocity is discontinuous at the corner between the paths,which leads to the frequent acceleration and deceleration,and it is an important factor in reducing the efficiency of work.How to realize the velocity smooth of the multi-path corner and the look-ahead velocity planning of cross-section is the difficulty of the path transition,which is the key technology that the robot manufacturer uses to improve the robot's work efficiency.In this thesis,an look-ahead trajectory planning algorithm for multi-path sections smooth transition is designed and a real-time online trajectory planning control scheme is built,which realize the smooth transition of multi-path sections,the main research contents is as follows:(1)The robot kinematics model is established.Based on the traditional geometric and analytical method to solve the inverse solution,a fast inverse method based on matrix factorization is designed and its accuracy and real-time performance are verified.In order to meet the spraying operation requirements,a 6 point method for tool coordinate is designed.(2)Based on the ladder velocity planning,the joint space trajectory planning algorithm and the cartesian space trajectory planning algorithm based on the S-type velocity programming are deduced.Cartesian space trajectory planning is divided into position planning and attitude planning.Linear position planning algorithm and arc position planning algorithm is included and an attitude planning algorithm based on quaternion is designed.(3)An look-ahead trajectory planning algorithm for multi-path sections smooth transition is designed.With the advantages ofG~1 continuity and the arc length parameterization,the arc curve is used to transit the corner between sections of path;The asymmetric S-curve acceleration/deceleration control is adopted for complete path segments;Under the constraint of path length and velocity,the look-ahead velocity planning of cross-section is used for segmented path segment.(4)An open real-time control shecem for the robot is designed and the hardware platform of control system is set up.A control system software platform with strong openness,high real-time and UI interface-friendly is designed.The LinuxCNC real-time system is configured and the driver of EtherCAT real-time Ethernet is transplanted;The mechanism based on multi-thread concurrent execution management scheduling and Ethernet communication technology is adopted in this control system.The look-ahead interpolation algorithm is integrated into the robot real-time control system in order to realize the real-time online planning. |
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