Study On Leveling Device Of An Ammunition Loading Vehicle

Ammunition loading vehicle is the logistics supply vehicle of combat equipment,its mobility performance is the key to determine the survival ability of main combat equipment,and whether one side can win the battlefield opportunity.Among them,how to solve the problem of rapid extension of ammunition loading vehicle leg and rapid and stable leveling of leveling platform has become one of the important concerns.At present,most of the pressure retaining devices used in hydraulic leveling circuit are bidirectional hydraulic lock pressure retaining circuit or balance valve pressure retaining circuit.However,the bidirectional hydraulic lock pressure retaining circuit is easy to produce shock and vibration.Although the current balance valve pressure control loop has developed into anti-impact,load control,locking load and other functions in one of the motion control components,the balance valve due to high price,will still be under a certain amount of pressure when the system stops the oil supply instantaneous,resulting in short life,frequent replacement which is not conducive to use in long-term pressure maintenance equipment.How to ensure the stability of the pressure retaining circuit and how to improve the service life of the circuit components become an urgent problem to be solved.The principle and application of hydraulic leveling system and its control algorithm are introduced in many literatures,but there are few literatures about automatic leveling system in ammunition loading vehicle.Based on the actual topic of technical improvement of a certain type of ammunition loading vehicle,the thesis focused on the research of the leg of the hydraulic leveling circuit,the control of the leg of the hydraulic circuit and vehicle body leveling control strategy.On this basis,the electronic control system was designed and tested.The main contents were listed as follows:(1)A new design of bidirectional hydraulic lock and balance valve in the same leg of hydraulic leveling circuit was adopted.The bidirectional hydraulic lock pressure retaining circuit,balance valve pressure retaining circuit and two pressure retaining components were shared in the same hydraulic circuit,and the simulation test of the working pressure of the three pressure retaining circuits was carried out respectively.The results showed that the new design using two pressure retaining components in the same leg of hydraulic leveling circuit has relatively less working pressure,but takes longer time to level.(2)The key components of the hydraulic leveling leg circuit were selected and the working stability of the hydraulic leveling leg circuit was studied.The closed-loop model of single-leg hydraulic leveling loop was established by AMESim hydraulic modeling and simulation platform.Using model identification method and MATLAB programming environment,the mathematic model of the corresponding closed-loop model was established when the piston rod moved to different positions.The stability of each mathematical model was analyzed by using Bode diagram.The results showed that the two pressure retaining components which share the same hydraulic leveling leg circuit works well.(3)The fuzzy PID control algorithm was used for the single leg of hydraulic leveling circuit.The comprehensive simulation analysis was made for the conventional PID control method,fuzzy PID control algorithm and genetic algorithm optimization method.The results showed that the fuzzy PID control method has good robustness and the control effect can meet the technical requirements of ammunition loading vehicle.(4)The study determined the highest point fixed leveling method and two point leveling method combined leveling strategy.The AMESim hydraulic modeling and simulation platform and Simulink logic control module were used to co-simulate the four leg hydraulic leveling circuit.The simulation results showed that the support leg has balanced force,stable speed and good dynamic performance.(5)The hardware and software of leveling electronic control system were designed and tested.Controller selected Siemens S7-1200PLC programmable controller.The hardware circuit was designed with it as the core,and the components were selected.The control software was designed,including PLC control program and touch screen man-machine interface.PROFINET communication mode based on industrial Ethernet realized the communication between PLC and touch screen.On the basis of laboratory debugging,the leveling test of the real car was carried out.The results showed that the developed electronic control system can meet the requirements of leveling control in the aspects of leveling accuracy,smoothness and speed.The research results have been preliminarily applied,and further tests on reliability and anti-interference capability are needed.