Research On Multifunctional Steering System Of Self-propelled Sprayer With High Ground Clearance

The multifunctional steering system is the main part of the plant protection type mechanical highland gap self propelled sprayer.Its function affects the machine’s operation efficiency,operation quality,tire wear and handling stability.In this thesis,the steering system of the high altitude self propelled sprayer is taken as the research object.A multifunctional and multi-function steering control anti-skid system is designed,and its mathematical model is established,and the joint simulation analysis and real vehicle test are carried out.The main research work is as follows:(1)The "magic formula" is used to establish the tire model,and the effects of sideslip angle and lateral force,longitudinal force and lateral force on tire sideslip characteristics are analyzed;According to Ackerman steering principle,the side deflection angle and turning radius of the wheel were analyzed mathematically by the steering wheel of two wheels,four wheels and crab rows.A two degree of freedom linear model and a spray machine reference model are established,and the steering dynamics of the sprayer is analyzed.(2)Taking the multifunctional steering system of the high altitude self propelled sprayer as the research object,the actual operation requirements of the highland gap self propelled sprayer are analyzed,and a multifunctional and multi-functional steering system is designed.The system can make the highland gap self propelled sprayer realize the coordinated switch between two wheels,four wheels and crab rows.According to the parameters such as system pressure of the high altitude self propelled sprayer,the important hydraulic components are calculated and selected.(3)Using AMESim and MATLAB / Simulink joint simulation,the angle following and tire sideslip characteristics of the multi-functional steering system based on Fuzzy PID and PID algorithm under step response,slope response and sinusoidal response are compared and analyzed.The results show that the designed system can realize the coordinated switching of two wheels,four wheels and crab,and meet the Ackerman steering principle.(4)According to the designed multi-function steering system,the test prototype was built,and the corner following,the tire sideslip characteristics and the turning car test were carried out.The turning radius of the sprayer in the two wheel and four wheel steering modes,the rotation angles,the pitch angles,the heading angles,the lateral angles and the acceleration of the X\Y\Z direction of the four wheels were measured.According to the obtained mass center side slip angle and yaw rate,the two wheel steering was compared with the four wheel steering system.Under the four-wheel steering mode,the turning radius and tire sideslip are significantly reduced,and the corner following characteristics are significantly improved.It shows that the designed multi-functional steering system based on Fuzzy PID algorithm and the joint control strategy of proportional feedforward and yaw rate feedback meets the actual operation requirements,and the operation effect under the four-wheel mode is better.