Research And Design Of Four Wheel Steering System Of High Clearance Self-Propelled Platform

High clearance self-propelled platform of research and development is to solve the late crop management difficulties of long-stalked crops such as maize, tobacco, cotton. For high clearance self-propelled platform,four wheel steering technology is adopted to increase the flexibility of the platform,including the speed of field work and the yield of the crop. At the same time,four wheel steering technology is adopted to improve the performance of uniform spraying, which provides quality assurance of crops. Therefore, the research on the four wheel steering system based on agricultural machinery has a reference value for the development of the corresponding equipment in our country. In order to complete the four wheel steering system of High clearance self-propelled platform,the related research is carried out in the following aspects.(1)In order to choose reasonable steering mode of four wheel steering system of platform,based on Ackerman Principle kinematic analysis of four steering mode(coordinated4WS,crab 4WS,conventional 2WS,Articulated steering) were fulfilled. and obtained the relationship between the lateral steering wheel and the inner steering wheel and the formula of turning radius. Compared with conventional 2WS, coordinated 4WS can reduce turning radius by 39.32%.(2)In order to adapt to different operating conditions and be easy to drive, High clearance self-propelled platform must have three steering mode(coordinated 4WS,crab4 WS,conventional 2WS).four wheel steering hydraulic system is suitable for the requirements of the agricultural machinery. The steering force analysis was carried out,and selection is applied to the hydraulic components of the steering hydraulic system including the steering hydraulic oil cylinder, the hydraulic pump, the steering gear, the priority valve, the prime mover, etc..(3)Based on software AMESim to build four wheel steering hydraulic system simulation model of high clearance self-propelled platform.and hydraulic components were simulated and analyzed,including full hydraulic steering gear, a priority valve, steering hydraulic cylinder. The results show that the design of four wheel steering hydraulic system can meet the design requirements.(4)Experimental study on the performance of the steering system.the satellite receiver which was installed on platform recorded path points of it.using ANOVA, a significant effect of analysis of the factors of road surfaces, turning directions,steering modes were fulfilled,indicating that significant differences in turning radius was detected between steering modes.The aligning distance when re-entering the crops and the headland width were used to evaluate the performance of platform.The results showed that coordinated 4WS significantly improves steering maneuverability of platform in headland turns.The increase of aligning distance would equate to about 2~3 seconds to make adjustmnets.horizontal path adjustment experiment of three steering mode were fulfilled,indicating that crab 4WS results in a smaller application and no part of surface area experiences multiple applications.From the research, the design of the four wheel steering hydraulic system meets the high clearance self-propelled platform, and according to the experimental results show that the four wheel steering system did improve vehicle maneuverability and spraying uniformity.