| Excavators are not only important machinery in modern construction,but also indispensable special engineering machinery in military and rescue.They play a key role in the modernization of national infrastructure and economic prosperity,and excavator robots are the important development direction of excavators.Trajectory planning of excavators is the basis for excavators to develop intelligently and automatically.Based on the normal digging theory,this topic carries out the research on trajectory planning of excavators.The research contents include:（1）Based on the shortcomings of traditional trajectory planning of excavator robot and the comparison of intelligent optimization algorithms,particle swarm optimization（PSO）algorithm with penalty function is selected to carry out trajectory planning,which can meet the operation requirements and avoid the problem of blind position and blind angle.A PSO trajectory planning model（PSO method）of an excavator robot was established based on the exterior penalty function method and the concept of blind position and blind angle,and the objective function was constructed based on normal digging theory.（2）In a simple path,with energy saving as the optimization objective,the trajectory planning effect and calculation efficiency of the empirical method,traditional optimization method and the PSO method were compared.Compared with the empirical method and traditional optimization method,the PSO method reduced the total change amount of hydraulic cylinder by 17.9% and 6.74% respectively.Compared with empirical method and traditional optimization method,the PSO method reduces the total time of path calculation by 36.6s and 36.1s.The effectiveness of PSO trajectory planning model is verified.（3）In the compound digging path,with energy saving as the optimization objective,the hydraulic cylinder’s moving of each joint is compared with the measured data of the path by PSO method.The simulation results show that the improved efficiency of the PSO method’s hydraulic cylinder’s moving is 8.63% compared with the measured path.In order to improve the digging force,the compound digging force curve corresponding to the measured path attitude and trajectory attitude is compared with the measured digging resistance curve.The values of the corresponding compound digging force are greater than the measured digging resistance value,indicating that the compound digging force model is in line with the actual operation requirements.The compound digging force corresponding to the trajectory attitude is increased by 4.52% on average compared with the measured path attitude.（4）In order to improve the excavation force and save energy,track planning is carried out on the compound digging path.Firstly,the compound digging force curve corresponds to the trajectory attitude and the measured path attitude is compared with the measured digging resistance curve.Both of them are above the digging resistance curve,and the compound digging force corresponding to the trajectory attitude is increased by 3.31% on average compared with the measured path attitude.Then,the hydraulic cylinder’s moving curves of each joint measured by the PSO method and measured data of the path are compared.The improved efficiency of the PSO method is 3.92% compared with the measured data of the path hydraulic cylinder’s moving.Finally,the trajectory planning optimization effects of two optimization objectives with different weight values are compared. |
