Research And Simulation Analysis Of Trajectory Tracking Of Excavator Working Device

In recent years,with the successive proposals and in-depth promotion of national policies such as "Made in China 2025","14th Five-Year Plan" and "Double-Carbon Plan",the development of my country’s equipment manufacturing industry has entered a new wave.The R&D and manufacturing of the "star" products are undoubtedly the top priority.The efficient performance of excavators in many fields of work has led to more and more researches on their transformation and upgrading.Intelligent and automated technology is an inevitable trend in the development of excavator products,which can not only improve the safety factor,reduce energy consumption,and adapt to harsh environments,but also reflect my countr y’s strong scientific and technological level and production capacity.In order to realize the intelligent mining of hydraulic excavator,this paper tracks the movement trajectory of the hydraulic excavator working device.After planning the bucket movement trajectory,different methods are used based on the idea of sliding mode control,iterative learning control idea and fractional order theory.The tracking effect of the actual trajectory of the excavator working device on the expected trajectory is stud ied.The main work are as follows:(1)Analysis of the kinematics of the excavator working device by using the D-H coordinate system method,the forward and inverse kinematics problems are studied,and the forward and inverse kinematics equations of the excavator working device are deduced.(2)The joint space trajectory planning method is investigated,and the interpolation methods of cubic polynomial and quintic polynomial are introduced.Then,the cubic polynomial and quintic polynomial methods based on the idea of single-node interpolation and multi-node interpolation are deduced in detail.Through comparison,it is found that(5-5-5-5-5)piecewise interpolation method has the ability to configure the starting point of the trajectory at the same time.and the effect of the velocity and acceleration values at the end point.Finally,it is verified by simulation that the method proposed in this paper has a smoother and more continuous mining trajectory during the operation.(3)Combined with the good robustness of the sliding mode control algorithm and the high tracking accuracy of the iterative learning control algorithm,the sliding mode control theory was introduced into the iterative learning control theory,and an iterative sliding mode position control ler was designed.The control strategy can avoid the problem of serious chattering when the system uses sliding mode control alone or the robustness is not strong when iterative learning control is used,so that the control system of each joint of the excavator working device has better control performance.(4)In order to further improve the trajectory tracking control accuracy of each joint of the excavator working device,an iterative sliding mode control algorithm combined with the control strategy of fractional calculus is used,and a fractional iterative sliding mode is designed through the definition and selection of the reaching law model controller.Compared with the integer-order iterative sliding mode control strategy,the fractional-order iterative sliding mode control strategy can suppress the chattering phenomenon to a certain extent,and the tracking performance is better,and the actual trajectory of each joint in position tracking and velocity tracking is highly consistent with the expected trajectory,that is the tracking error is much smaller than the integer order iterative sliding mode control strategy.