| Liquid sloshing in the tank of a high clearance self-propelled sprayer is an important factor that reduces its driving smoothness and spraying quality.To address this problem,this paper intends to take the chassis suspension,which has an important influence on the performance of the sprayer,as the research object,and use the frontier theories and technical achievements of vibration theory,liquid sway and nonlinear system dynamics to analyze the liquid sway motion characteristics of the tank and its influence on the vehicle with the timevarying quality factors,and on this basis,carry out the analysis of the dynamic characteristics of the chassis suspension system and parameter optimization design research,in order to To improve the driving smoothness and spraying quality of spraying machine,and provide theoretical support and realization ways for the design and development of chassis suspension of large high clearance self-propelled sprayers in China.The main contents and conclusions of the study are as follows:(1)An equivalent mechanical model was used to analyze the characteristics of liquid sloshing motion in the spraying machine tank.The spring-mass-damping equivalent model is established,and the key parameters of the equivalent model were solved by the analytical method and simulation fitting method.Then,the effectiveness of the proposed equivalent model was proved by simulating the liquid shaking test and comparing with the simulation test.(2)The influence of liquid factors on the smoothness of the sprayer and the quality of spraying was investigated.A four-degree-of-freedom vertical dynamics model of the sprayer transverse and longitudinal semi-vehicle was established,and Matlab/Simulink smoothness response comparison tests were conducted.The test results showed that the liquid inside the tank was forced to shake the impact effect significantly reduces the whole machine vertical acceleration,lateral tilt angle speed and pitch angle speed when the vehicle was driving.At the same time,it was found that when the filling ratio is 0.8,the pitch angle speed of the whole vehicle is maximum,while when the filling ratio is 0.6,the side tilt angle speed of the whole vehicle reaches the maximum.(3)Based on genetic algorithm and Simulink dynamics simulation,multi-objective optimization of the undercarriage suspension parameters of the sprayer was carried out to obtain the optimal parameter matrix of the suspension under different liquid-filling conditions during the transfer and spraying operations of the sprayer.The Matlab/Simulink smoothness simulation test of the whole sprayer was carried out under the optimal parameters.The test results show that the maximum optimization effects of body vertical acceleration,lateral tilt angle speed,pitch angle speed and dynamic wheel load can reach 27.5%,16.4%,25.8%and17.6%,respectively.(4)A small high clearance self-propelled sprayer designed and manufactured by our team was used to conduct the sprayer real vehicle tests.Four sets of replicated tests were conducted according to the different driving surfaces(field and non-field surfaces)of the sprayer for transit transportation and spraying operations,and the different suspension parameters before and after optimization(initial and optimized parameters).The test results showed that the vertical acceleration of the sprayer’s spring-loaded mass was much smaller than the acceleration of the unsprung mass,and the adjustment of the suspension parameters reduced the vertical acceleration of its body by 10.23% and 15.97% under the two wheel running surfaces,respectively,in addition,the body roll/pitch angular speed was reduced by more than 10%. |
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