Design And Research Of Four Wheel Independent Steering System For Gantry Elevated Work Vehicle

In recent years,with the improvement of China's economic level and the development of science and technology,agriculture has gradually modernized.The main high-crop crops in Henan include corn and tobacco.During the planting and harvesting stages,high mechanization levels have been achieved,but most of the cultivating work such as tobacco topping,weeding,spraying,and corn emasculation in the middle and late stages of planting It is still artificial,and the degree of mechanization is low.After investigation and research,the reason for this situation is mainly because the high-bar crop overhead work vehicle has a mismatch between agronomic and work vehicles when working in the field.It is difficult to enter the ground during the operation,the turning of the field is difficult to turn and the turning radius is too large.In order to solve these problems,this paper designed a gantry elevated work vehicle with high passability,variable wheelbase and four-wheel independent drive steering.The four-wheel independent steering system was designed with four wheels.The wheels of the independent steering system do not interfere with each other,and can be independently steered,and are coordinated and controlled by the electronic control system.The steering algorithms are used to realize the Ackerman steering relationship between the wheels,and various steering modes and variable pitch functions are realized.Design an independent steering system.The design is divided into two parts:the first part is to design the steering four-bar mechanism of the corner actuator,and the second part is to design the hydraulic control system of the steering part.In this paper,the independent steering four-bar mechanism is designed,and the position analysis of each member of the mechanism is carried out.Then,through mathematical calculation,MATLAB software calculation and Adams dynamic simulation,the hydraulic cylinder elongation and the four-bar mechanism follower rod are obtained.The relationship between the AD corners is mathematically expressed as.Design the hydraulic system of the whole vehicle.The vehicle oil circuit includes three parts:the traveling hydraulic circuit,the variable distance hydraulic circuit and the steering hydraulic circuit.The steering hydraulic circuit is designed and the control scheme of the steering hydraulic circuit is studied.The hydraulic simulation software AMESIM is used to control the steering hydraulic system.Modeling and analyzing the response characteristics and following characteristics of the hydraulic system with PID control,the results show that the response speed is basically satisfied,but the following performance is poor.Using AMESIM/Simulink co-simulation,the hydraulic system with fuzzy PID control is performed.The simulation analysis shows that the system with fuzzy PID control has better position accuracy,response characteristics and follow-up characteristics compared with the conventional PID system to meet the design requirements.The electronic control system of the steering system is designed.The hydraulic components and electrical components required for the steering hydraulic control system are selected.The controller is programmed according to the control idea.The front wheel test bench is built for test analysis.The test results indicate the designed steering hydraulic pressure.The control system has certain practical significance.The positional accuracy of the system is ±2.lmm,and the response time is 1?2s.It can follow the continuous signal and meet the design requirements.