Research On Design And Control Strategy Of Four-wheel Independent Steering System For Greenhouse Work Platform

Aiming at the problems of large space occupied by agricultural machinery in greenhouses,difficult steering and complex steering mechanism,this paper redesigned a new type of four-wheel independent steering system based on a small working platform,and analyzed the control scheme of the traditional steering system.The adaptive genetic algorithm fractional-order PID control strategy suitable for the design of this paper is proposed.The purpose is to enable the work platform studied in this paper to realize multiple steering modes such as in-situ steering,walking steering,lateral driving and oblique driving.The main research contents include:(1)By analyzing the working environment of the greenhouse and the structural characteristics of the four-wheel independent steering system,the overall design plan of the four-wheel steering system of the greenhouse working platform is proposed.On the basis of this plan,the components,components and the inter-parts are calculated.The relationship and other parameters are verified by the ADAMS engineering application software.(2)The design and selection of the hydraulic system of the greenhouse work platform.Based on the overall design plan of the platform steering system,and according to the design criteria of the hydraulic system,two different hydraulic system plan designs suitable for platform steering are proposed.Comparing the two with each other,the second scheme is obtained.The structure is simple and easy to implement,which reduces the complexity of the entire steering system to a certain extent.After the scheme is determined,the relevant parameters of each component in the hydraulic system are calculated,and the calculated data is compared with the relevant data.The relevant parameters of the corresponding parts on the market are compared,and the parts with the best cost performance are selected.(3)Research on control strategy of greenhouse working platform.First of all,the research on the control strategy of this platform is based on the theoretical design method of classical PID controller and the fractional-order control theory,combined with relevant theoretical knowledge,proposes an adaptive genetic algorithm fractional-order PID control strategy suitable for this platform.Secondly,based on the two-degree-of-freedom model of the operating platform,the MATLAB/Simulink module is used to establish a four-wheel independent simulation model of the operating platform.By comparing the response characteristics of the system under different control strategies,it is concluded that the overall performance of the designed control strategy is optimal and meets the design requirements.(4)Establish dynamic model and simulation data analysis of operating platform steering simulation system.First of all,establish the steering mechanism model of the ADAMS operating platform.On this basis,the control sub-modules and their respective data conversion modules are established in Simulink by using the angle relationship and the speed relationship.Secondly,the adaptive genetic algorithm is introduced to further design and process the fractional PID controller,and the above-mentioned control model established by Simulink and the virtual prototype model are integrated for simulation,and the steering system and the control strategy adopted in this paper meet the design requirements.(5)Through simulation and analysis of special working conditions,it is concluded that the steering system of the work platform can meet the design requirements of various steering modes,has the function of steering synchronization,and has a small steering radius and strong stability.