Path Tracking And Anti-rollover Control Of High Gap Four Wheel Independent Drive Sprayer

Agricultural problem has been the main problem of our country’s development,and its level of development concerns the lifeblood of our country’s economic development.At present,Chinese agricultural development still faces various difficulties.For example,the loss of rural labor force,the transfer of land,the increase of farming scale.In order to promote the development of Chinese traditional agriculture in the direction of intelligent and modern development,the country puts forward the slogan of developing smart agriculture.According to the upgrading and transformation of traditional agricultural equipment,the representative of which is high gap sprayer.Most of the traditional highland gap sprayer adopts semi-mechanization for plant protection,and all of them are manned with a low intelligence level.Therefore,the development of an efficient and safe unmanned highland gap sprayer is of great significance for the prevention and control of crop diseases and pests,the reduction of environmental pollution,and the improvement of grain production.In this paper,the intelligent transformation is carried out for the chassis model of the sprayer designed for future unmanned autonomous driving,and the path tracking control and anti-rollover control of the high-gap sprayer are studied respectively.The main contents are as follows:(1)Aiming at the shortcomings of the traditional sprayer,a new chassis structure of the sprayer is proposed,and the kinematic model of the sprayer is established based on this structure.The virtual prototype model of the designed sprayer is established in ADAMS,and the constructed virtual prototype model is verified.Adams/Car is used to build different simulated road surfaces to simulate the complex field working environment of the sprayer,which lays a foundation for the subsequent path tracking control and anti-rollover control of the sprayer.(2)Based on the kinematic model of the sprayer,the path tracking control of the sprayer is realized by model predictive control(Model Predictive Control,MPC).On this basis,the influence of turning radius and prediction time domain on the path tracking accuracy was deeply analyzed,and the approximate change mechanism of the turning radius in the prediction time domain was summarized.An MPC controller which could be adjusted in real time according to the turning radius of the sprayer was designed to ensure the accuracy of the path tracking of the sprayer.The co-simulation platform of Adams and MATLAB is built to verify the adaptive MPC algorithm.The simulation shows that the designed adaptive MPC controller has good control effect.(3)Aiming at the situation that the sprayer may roll over in plant protection operation in complex field environment,an anti-rollover strategy is proposed.The fuzzy control idea is adopted to adjust the steering Angle and improve the force,so as to stabilize the body attitude and prevent rollover.The co-simulation results of Adams and MATLAB show that the designed anti-rollover controller has good control effect.(4)The A&D5436 real-time simulation system was used to build a 4WID high-gap sprayer experiment system,and the adaptive MPC path tracking and anti-roll-over control algorithm were verified in real vehicles.The control algorithm was tested based on the straight line,turn and U-bend conditions.The experimental results show that the path tracking controller and anti-rollover controller of the sprayer designed in this paper have better control functions,it not only ensures the better tracking accuracy of the sprayer in path tracking,but also ensures the safety of the sprayer so that it does not roll over.