Research On Steering Characteristics And Optimal Control Strategy Of Nine Axis All Terrain Crane

Large tonnage all terrain have advantages of longer body and multi-axle, so bring about a lot of problems in operation and the steering travel, especially the steering problem. Although the multi-axis steering technology is adopted, but the domestic research of this technology is not very mature and many key technologies can not be obtained from abroad. So it needs further research on multi-axle steering technology. The steering performance and control strategy of a certain type of nine axle all terrain crane are studied in this paper.Firstly, according to the law of motion, the two-freedom mathematical model and dynamic differential equation of the vehicle was established. According to the principle of multi-axle steering and the calculation formula of the wheel angle of each axle, the instantaneous steering center position of the vehicle was determined and the calculating formula of the minimum turning radius was obtained. In order to minimize the side bias power loss of tire, through the optimization analysis, the expression of the sideslip angle and longitudinal force was obtained. According to the expression of the sideslip angle can ensure the tire wear minimum caused by steering.Secondly, the operation stability of the different steering modes was analyzed. The expression of steady state and time response parameters was obtained by calculation. In order to analysis three kinds of nine axle vehicle steering models, simulation model was established, the response of steady state, time domain and frequency was simulation studied by MATLAB software. Through the analysis to compare the advantages and disadvantages of different steering modes.Finally, based on optimal control strategy, the optimal controller of the nine axle all terrain crane was designed, when the whole wheel steering was used, the wheel angle of each axle was optimal controlled. The simulation model of steering system is established and the simulation analysis was carried out. The results show that this control method can ensure the minimum steering radius of the vehicle at low speed, and the high speed is not due to the lack of too much to reduce its flexibility.