Excavation Trajectory Planning Method Based on Path Coarse Interpolation

This paper analyzes the advantages and disadvantages of Cartesian space trajectory planning and joint space trajectory planning. To achieve the balance between efficiency and accuracy of trajectory planning, an excavation trajectory planning method based on path coarse interpolation is proposed. Firstly, a kinematic model of the excavator is established, and the excavation path is determined. Then, the excavation path is coarse interpolated in Cartesian space and divided into multiple excavation key points. Finally, the trajectory planning is carried out in the joint space. Taking space line and space arc as examples for simulation analysis, the simulation results show that the actual path under this method coincides with the planned path highly, and the maximum error and average error in X and Z direction are both less than 0.01mm, which ensures the accuracy of path execution and has small amount of calculation. This method achieves a balance between trajectory planning efficiency and accuracy.

1. INTRODUCTION

In the process of excavator operation, trajectory planning is the key to realize excavation intelligence and improve excavation efficiency. Therefore, many scholars have carried out a lot of research on trajectory planning of excavator. In excavator excavation trajectory planning, the main methods are Cartesian space trajectory planning and joint space trajectory planning [1]. In Cartesian space trajectory planning, the position, velocity, and acceleration of the bucket tip are directly planned, and the commonly used methods are T-shaped or S-shaped acceleration and deceleration planning [2]. This method can ensure that the bucket tip executes excavation actions according to the specified path, but it requires inverse kinematics calculation to obtain the mutual conversion between joint space and driving space. The planning process requires a large amount of calculation, making it difficult to achieve real-time control of the excavator. Therefore, joint space trajectory planning method is usually used in excavators.