Research On Driving Stability Control Of High-Gap Sprayer

The high-gap sprayer fertilizes high-stalk crops such as corn and sorghum at the early stage to prevent disease in the middle stage,and in the later stage of the disease and pest control process,it is popular with users because of its high work efficiency.However,the center of gravity of the whole vehicle is relatively high,and the working road environment is complicated,which further aggravates the difficulty of controlling the driving stability of the vehicle.In this paper,while considering the structural characteristics of the high-gap sprayer,while taking into account the vehicle operating conditions and traditional vehicle control methods,the following related researches on the driving stability of the High-gap sprayer are carried out:(1)By investigating the structure and characteristics of the existing High-gap sprayer vehicles,analyzing the problems existing in the agricultural plant protection vehicle industry,first simplify the physical structure of the entire vehicle;then perform the force analysis of the entire vehicle based on the simplified physical model to derive the entire vehicle dynamic mathematical equations,and build a driving stability simulation model based on mathematical equations;finally,the correctness of the model is verified under high and low speed,straight and sinusoidal driving conditions.(2)Aiming at the problem of poor driving stability control effect of High-gap sprayer,a driving stability control strategy of direct yaw moment control is proposed.Firstly,based on the sliding mode control theory and the direct yaw moment control method,the coupling variable yaw rate and the error between the body side slip angle and its ideal value are used as the control input,and the direct yaw moment is the control output.A reasonable sliding mode function and approaching rate function,design a sliding mode controller;then,by analyzing the applied resistance-braking force to control the driving state of the vehicle,reverse reasoning and design 5 kinds of active control to realize the driving stability of the vehicle by change the driving torque;Through the simulation test of the control method under low-speed conditions,it is found that the average absolute value of the yaw rate error of the sliding mode controller is reduced by 7.70%,and the body side slip angle is reduced by 0.54%,which improves the vehicle’s driving stability at low-speed operation.(3)Through the design of the quadratic rotation orthogonal combination test and the response surface method,the relationship between the realization plan of the direct yaw moment,the operating speed,the load and the driving stability of the high-gap sprayer is explored.The simulation results show that the three factors all affect the driving stability;The designed direct yaw moment five realization plans can effectively improve the driving stability of the vehicle,but the plan of changing the inner driving vehicle wheels has the most significant effect;It is recommended to work at a driving speed of 1.5 m/s during the operation,try to keep the load near 1000 kg,and at the same time adopt the change of the inner wheel logic control scheme as the driving torque control scheme under low-speed operating conditions.(4)In view of the driving stability controller of high-gap sprayer under high and low speed working conditions,the design is compatible with the driving stability layered controller that takes into account both high speed and low speed working conditions.The upper layer is designed with a sliding mode controller and a fuzzy sliding mode controller to calculate the numerical value of the direct yaw moment;the lower layer controller contains logic judgments and actuators,and respectively selects the change of the inner wheel control scheme and the four-wheel simultaneous change of the wheel logic control scheme as low-speed and high-speed working condition execution plan.Among them,the focus is to use fuzzy intelligent control methods to improve the sliding mode controller and optimize the shortcomings of unsatisfactory control effects in high-speed working conditions.