Abstract: In this work, an optimal control scheme with adaptive weighting coefficients is presented which coordinates different vehicle dynamics control objectives, thus ruling out possible conflicts among them. In a new approach, the weighting coefficients in optimal control are adjusted according to the vehicle state in the phase plane in such a way that a priority is given to each objective of handling and stability in each region. The optimal control acts as a high-level control for the vehicle body, which determines the body lateral force and yaw moment for stable vehicle motion. The body lateral force and yaw moment provide the inputs to the mid-level force (control) distribution module, which works out the desired lateral and longitudinal forces at each wheel. Therefore, the high-level control objectives are allocated to individual tire forces in an optimal manner with the assumption of a 4-wheel-independent car. A low-level control uses the desired individual tire forces to compute the steering angle and applied torque at each wheel. Simulation tests with a nonlinear vehicle model are conducted and comparison with the well-recognized work in the literature is made to show the efficiency of the proposed method.  پرونده مقاله

Suspension system as one of the most important key elements of vehicle has always been considered by research centres and auto makers over the world and this issue is more important on sport cars which have special sensitive working conditions and even the smallest defect can strongly affect their performances. In this study, optimization of effective handling parameters of a sport car with three optimization indices is favourable cover racetrack at the shortest possible time. For this purpose a sport car model simulated in ADAMS/car software has been used and all test steps have been implemented in this environment. At the end of reaching optimum solution in different racetrack conditions, Pareto solution set optimization method has been used and in this problem, optimization indices have been examined which is covered distance in standard constant radius test with three different radii. so, by implementation of these experiments at different levels of optimization parameters, all solution sets are collected in a three dimensional diagram called performance space whose coordinates axes are optimization indices values, then using LP norm idea, possible optimum solutions are selected from among other solution and in order to find optimum solution in a special racetrack, a new idea has been proposed, through this, weighted coefficients related to each optimization indices for a special racetrack are determined and optimum solutions appropriate for that track is selected from pareto solution set. پرونده مقاله