Multi-objective trajectory planning of segment erector considering error uncertainty

Abstract

To meet the requirements for automation and precision in segment assembling and enhance the quality and efficiency of assembly, a multi-objective trajectory planning method considering error uncertainty is proposed for the trajectory planning strategy for segment erector under the conditions of heavy load and low-speed assembly. Based on the forward kinematics model of segment erector, the working space of segment erector is determined by Monte Carlo method, and the key track points are determined according to the actual operation requirements. The kinematic mapping relationship between Cartesian space and joint space is established based on the inverse kinematics model of segment erector, and the trajectory planning is carried out by using 5th-degree B-spline and 5th-degree polynomial respectively. Considering uncertainty errors caused by structural parameters, environmental factors, and joint space, the time, energy, and impact objective functions are established, and the comprehensive optimal trajectory is obtained based on the elite non-dominated sorting genetic algorithm II (NSGA-II). The results show that this method is an effective trajectory planning solution, which ensures that the segment erector moves smoothly, and has obvious advantages in reducing time, energy, and impact during the moving process.