System Control And Kinematical Simulation Of Four-Wheel-Independent-Steering Vehicle

As the "swifter, more flexible and more maneuverable" becomes the current thought of the army, and the panzer with wheel turns to the trend, it necessarily becomes the subject of study to enhance the flexibility, maneuverability and stability of the panzer. 4WIS(Four-Wheel-Indepen dent-Steering) based on the Ackerman theorem just can supply a feasible scheme for this subject. In the paper, aiming to the shortage of the research on the 4WIS and using the MATLAB software, the theory of optimum control and the MSC .ADAMS software, the modeling of the system, the control strategy & method and the kinematical simulation of the 4WIS are researched deeply and some creative achievements are gained which possess important value in theory and practice. Main achievements summarize as follows:1. The mathematical model of a 4WIS vehicle based on 3DOF is built for the first time. According to the control strategy, the function expressions of the angles of 4WIS vehicle based on 3DOF are derived. Based on this, the SIMULINK model is built and simulated, the results indicate that, in the control strategy of making the steady state sideslip angle of mass center equal to zero, the maneuverability at low speed and stability at high speed of 4WIS vehicle is improved compared with that of FWS and 4WS vehicle.2. The state space of 4WIS vehicle based on 3DOF is described, based on this, a linear quadratic optimum controller(LQOC) is applied to the SIMULINK model of 4WIS vehicle based on 3DOF for the first time. By simulation of the model of 4WIS vehicle with LQOC and the former, the results indicate that the LQOC can enhance the stability, celerity and veracity, and the capability of anti-jamming in high speed of the vehicle system.3. The VP(Virtual Prototyping) model of 4WIS vehicle is established using the software of PRO/ENGINEER and ADAMS/View in this paper. The expression of 2-order-fit function relation between the displacement of the tie rod and the steering angle of the tire is got through the simulation experiment. The method of controlling 4WIS based on 3DOF was used, and the simulation of the 4WIS,4WS and FWS vehicle VP model is processed.The law of motion is ulteriorly explored that the process of steering is smoother compared with that of FWS and 4WS vehicle and the capability of overtaking is superior.4. The kinematical simulations of the vehicles based on 4WIS in different steer modes are carried through combining with practice. The methods of the steering, drive control and realization of the inclined move mode and the spot steering mode are first obtained.