Research On Roll Stability Control Of High Clearance Sprayer

High ground clearance sprayer is a large modern agricultural equipment.Because of its characteristics such as high center of mass,large ground clearance,and large single drug loading capacity,it can meet the needs of high-stalk crops such as corn in the middle and late stages of pesticide application.During its steering or operation,due to the external excitation and changes in the internal parameters of the system,the roll stability of the entire machine becomes poor,and it will face the risk of rollover in severe cases.This article takes the high ground clearance sprayer as the research object and aims to improve its roll stability.The roll stability control system scheme design,the whole machine dynamics modeling and control method research are carried out.The main research work are as follows:(1)After analyzed the unique system structure characteristics and stability influencing factors of high ground clearance sprayers,applying motion control to the mass of the pesticide tank was proposed to keep it steady in this paper.Reducing the roll moment to improve the roll stability of the whole machine is the main research content of this paper and formulates the corresponding technical route.(2)A roll dynamic model was established for the high ground clearance sprayer.Analysis shows that the roll stability has a certain relationship with the roll angle and lateral acceleration during driving or operation.The two factors can generate a rolling moment and change the vertical load of the tire.The lateral load transfer rate(LLTR)is used as a comprehensive evaluation index of roll stability.Based on the structural parameters and layout of the test platform designed by the members of the research group,the design requirements for the motion attitude control of the pesticide tank were proposed.Based on this,an active leveling system suitable for the test platform is designed,and the feasibility analysis of the system design scheme is performed using the inverse kinematics solution method and simulation analysis.(3)A dynamic model of the machine with 16 degrees of freedom was established,and the dynamic relationship between the critical value of roll instability and its lateral load transfer rate and the roll angle,lateral acceleration,and system structural parameters was analyzed according to the dynamic model.In order to verify the dynamic relationship between the various components of the system,ADAMS was used to establish its virtual prototype model and its simulation analysis under different operating conditions.The maximum load transfer rate reached 0.89.(4)Aiming at the characteristics of non-linear,uncertain and time-varying parameters of the high ground-gap sprayer,a corresponding control strategy was formulated and designed a grey predictive fuzzy PID control algorithm controller.Simulation analysis based on AMDAS and MATLAB and comparison with other two control algorithms.The results show that the gray fuzzy PID control algorithm proposed in this paper can make the leveling system response faster and more accurate under the action of step signal and sinusoidal signal input,and it can better meet the control requirements of the leveling system.It was also applied to the roll stability control of the high ground clearance sprayer under three operating conditions,and good control results were obtained.The lateral load transfer rate was reduced by 33% in the slope operating condition and the steering condition down by 42% and 34% under field conditions.(5)The test platform of the active leveling system is designed and built,and the response characteristics of the active leveling system are experimentally verified based on the test platform.The experimental results show that,in the step response and sinusoidal response tests,the comparison of the effects of the three different control algorithms is consistent with the simulation results.The gray prediction fuzzy PID control algorithm has the best effect.Based on this,it can be seen that the gray-prediction fuzzy PID control algorithm proposed in this paper can well achieve its requirements of fast response and accurate control,and the good control performance of the algorithm is further verified through simulation tests of slope operating conditions.