Research On Flow Matching And Trajectory Control Of Large Intelligent Excavators

Excavators have strong applicability and occupy an extremely important position in construction machinery,and have a huge demand worldwide.Manually operated excavators are difficult to meet the increasingly high requirements in terms of operating environment,operating efficiency and operating costs,and intelligence is a major trend in the development of excavators.However,most of the current research on hydraulic excavation robots is aimed at medium and small excavators,and the mechanical structure and electro-hydraulic control system of the excavator are modified to a large extent,and the selected sensors are not suitable for the excavation environment.In this thesis,for 95 t mining excavator,the intelligent operation of large excavation robot with autonomous planning of excavation is the goal,and the research on its trajectory planning,trajectory control and flow matching is carried out.The main work is as follows:First,the structural parameters of the 95 t large excavator and the working principle of the positive flow hydraulic system are introduced,the energy-saving characteristics of the positive flow control system are studied,and the control method used for the positive flow system of the excavator is described.Second,the kinematic analysis of the excavator was carried out,and the displacement and velocity mapping relations of Cartesian space-joint space-actuator space were deduced.An excavation robot trajectory planning method was designed to obtain the actuator planning trajectory after cubic polynomial planning.Simulation experiments of the excavation robot were conducted in robotics toolbox of MATLAB to verify the feasibility of the trajectory planning method.Third,a trajectory control system with feedback from the tilt sensor was designed,a mathematical model of the valve-controlled asymmetric hydraulic cylinder was established,and a PV controller was designed.The AMESim-Simcenter3 D Motion joint simulation model was established,and single-action and compound-action tracking tests were conducted.The simulation results show that the PV controller has a good control effect and can meet the control requirements of the excavation robot.Fourth,the flow matching method of the existing electro-hydraulic control system is analyzed,and the flow matching method based on the planning trajectory is proposed and the control simulation is carried out.According to the simulation results,the computational flow system enables the valve and pump control signal coupling to be separated,and the pump output flow and system pressure are stable,which improves the control performance of the system.The demand flow is calculated according to the planning trajectory,which can be taken on demand and improve the energy utilization efficiency,while solving the heavy load action hysteresis problem.Finally,the prototype was modified based on a 95 t large excavator,and the trajectory planning and control program was written in the Linux system upper computer.The trajectory planning method and trajectory control of the test prototype under single action and compound action were studied,and the control parameters were optimized.The actual excavation test research was conducted to optimize the trajectory planning method and parameters,and initially realized the autonomous trajectory planning and excavation operation of the excavator.