Research On Inverse Problem In Vehicle Handling Stability And Ride Comfort

The character of vehicle handling dynamics affects vehicle handling handiness, and is a main performance index determining safe running for high speed vehicle. In the case of vehicle high speed turning, driver model parameters are not easy to determine, which makes driver model difficult to bulid. In order to avoid the problem, driver handling input is calculated by the handling inverse dynamics method.Aiming at the limitation of current research method for road surface roughness, the road surface roughness identification method is studied by the thinking of inverse problem. It establishs the foundation for vehicle ride comfort , and provides the basis for the anlysis of road surface performance.(1)Based on RBF neural networks, a simulation research method of road surface roughness identification in the field of frequency is put forward. Based on four degree-of-freedom and seven degree-of-freedom vehicle vibration model, the vehicle body centroid vertical acceleration and pitching angular acceleration which are got through Matlab simulation are regarded as neural networks ideal input sample, the imitated road surface roughness is regarded as neural networks ideal output sample. The nonlinear mapping relations among vehicle body centroid vertical acceleration, pitching angular acceleration and the road surface roughness are found by RBF neural networks. Another vehicle body centroid vertical acceleration and pitching angular acceleration which are calculated by simulation are used to identify road surface roughness by trained networks. Simulated results show that the method has better ability of anti-noise and ideal identification accuracy, the road surface roughness of identification fits the imitated road surface roughness.(2)Based on RBF neural networks, a simulation research method of road surface roughness identification in the field of time is put forward. The nonlinear mapping relations in the field of time are found by RBF neural networks . Another vehicle body centroid vertical acceleration and pitching angular acceleration which are calculated by simulation are used to identify road surface roughness by trained networks. Finally another vehicle body centroid vertical acceleration and pitching angular acceleration which are got by ADAMS/View virtual experment simulation are used to identify road surface roughness. So the availability of road surface roughness identification by RBF neural networks is validated .(3)A simulation research method for identifying the angle input and the force input in vehicle handling inverse dynamics is proposed under the condition of different vehicles tracking the same given path. In this method, the linear vehicle model of steering angle input with two degree-of-freedom and steering momemt input with three degree-of-freedom are adopted, and the optimal control theory is used to identify the steering angle input and the steering moment input. By using the direct parallel method, the optimal control problem is converted into a nonlinear programming problem that is then solved by means of the sequential quadratic programming. Simulated results show that the proposed method is of good path-tracking ability; is able to compare the maneuverability of different vehicles that track the same path; and the movement trend of simulated results is similar to that of actually experiment.(4)A simulation research method for solving vehicle minimum time maneuver problem is proposed. Based on optimal control theory, steering angle input and traction/brake force imposed by driver are control variables, the minimum time required to complete the double lane change and slalom is control object. By using the direct parallel method, the optimal control problem is converted into a nonlinear programming problem that is then solved by means of the sequential quadratic programming. Matlab simulation results are obtained for two different vehicles performing similar given path boundary by the method. Simulated results show that the proposed method can solve vehicle minimum time maneuver problem; compare maneuverability of two different vehicles that complete double lane change and slalom with the minimum time; and the results fit the results of ADAMS/Car virtual experment.