Study On The Modeling And Control Strategy For Lateral Stability Of High-Gap Sprayer

The self-walking High-Gap sprayer has been widely used in the control of crop pests and diseases on farmland and orchard because of its efficiency and good spraying effect.However,due to its high center of gravity and complex work environment,the wheels are stimulated and severe vehicle-liquid coupling when the sprayer is operating on the ramp stochastic road,which not only affects the spraying effect but also causes the sprayer to roll over.Therefore,the problem of the passability and lateral stability of sprayer has become the core problem to limit its technology popularization.However,the research about the stability of the lateral is mainly aimed at cars,buses,heavy goods vehicles and engineering special vehicles.Under this background,learn from the predecessors’ lateral stability of conventional vehicles and liquid tankers and combined with the special working conditions and structure of the sprayer.In this paper,the active safety technology of the sprayer is studied,and the development of the controller is of great significance to the driving safety of the sprayer.In this paper,the dynamic model of vehicle-liquid coupling for sprayer is established.Based on the dynamic model of vehicle-liquid coupling,a fuzzy PID control strategy of variable domain is proposed.Finally,based on the principle of similarity criterion of proportional model,the test system of vehicle proportional model is built,and the fuzzy PID control strategy of variable domain is verified.The main tasks are as follows:1.Based on the actual operating conditions of the sprayer,the fluid volume method(VOF)is used to simplify the coupling dynamics of sprayer.Firstly,the isolation method is used to obtain the accelerated physical model when tank is excited by the road surface.Secondly,the kinetic analysis of fluid forced shaking in tank is analyzed,which based on the accelerated physical model of tank when it is stimulated by the stochastic road,the impact force of tank’s wall is numerically simulated by using Fluent software under the excitation of the lateral acceleration under different working conditions(different filling ratio,working speed and pavement inclination).Finally,using Matlab to fit the impact force curve,and the impact function beam of the sprayer under different working conditions is obtained.The impact function is loaded into the centroid of Adams virtual sprayer,which successfully solves the working condition that Adams cannot define and simulate the sprayer under variable load.2.A three-dimensional virtual prototype model of sprayer vehicle is established,select Fiala to parse the tire model in Adams and set the relevant parameters.In this paper,the principle of Adams uneven random pavement is introduced,and the road unevenness coefficient required for simulation is selected.Using the harmonic superposition method,the E and F level unevenness coefficients are fitted by Matlab,which the data exchange with Adams is realized.Based on the design principle of Taguchi test,test design of three factors and three horizontal is designed with the stochastic pavement of class E and F as the noise factor.Through the virtual simulation test,it is obviously than the LTR change to consider the liquid impact in the simulation,which the correctness of the combined simulation of Adams and fluent vehicle-liquid coupling dynamics under variable load is proved.3.In this paper,a vehicle-liquid coupling dynamic control model with stochastic road of tire that class E and F slopes is established in Adams/view,and the control parameters of acceleration stability during operation are deduced by establishing the mathematical model of six degrees of freedom of sprayer.Based on the principle of acceleration stability control,this paper determines the input and output of Adams virtual sprayer model with the help of Adams/controls module.Based on the theory of variable domain,the fuzzy PID controller of variable domain is designed,and the simulation platform of sprayer stability control system is established in Simulink,and it is found by the Co-simulation of Adams and Simulink that the application of variable domain fuzzy PID can ensure the stability of the sprayer’s lateral acceleration at ±2g,The pitch acceleration is stable at ±4g,which the safety margin is higher and the control effect is better than that of ordinary fuzzy PID and PID control strategy.4.Based on the similarity criterion of proportional model,this paper mainly uses 3D printing technology,the walking system,spray rod,frame and water tank of printing sprayer,and forms the proportion model of sprayer after assembly.The random pavement of E and F is made based on the international standard of pavement spectrum.According to experimental conditions,the microcontroller and sensor are selected,and the construction of the model test system of proportional sprayer is finally completed.The fuzzy PID control strategy of variable domain is verified by experiment,and the relative error between the simulation value of vertical load transfer rate,the attitude change of lateral and pitch acceleration and the experimental value is less than 20%,and the simulation value is basically consistent with the experimental results,which further illustrates the feasibility of the fuzzy PID control strategy of the variable domain.