Vehicle Chassis Integrated Control Based On Multibody Dynamics Model

With the development of technology, in order to improve the vehicle comfort, handling and active safety, a variety of dynamic control systems such as electric power steering system (EPS), active suspension system (ASS), anti-lock braking system (ABS) have successively applied to the modern car. In the integrated control design of these systems, two important issues --- the setting up of the model and determination of the control strategy become the research hotspot which the experts and scholars study in recent years.The paper described the research significance of the integrated control of chassis, discussed the necessity of it; introduced the uses of control structures ,algorithms and models; the research status of the integrated control was summed up.The EPS and full vehicle equipped with ASS multibody models were established by the Cartesian coordinates method, and applied to the control studies. The returnability control were carried out which making use of the steering load characteristics which well reflected by the EPS multibody model. The simulation results verify the control effect.Based on the motion coupling relationships between steering and suspension systems, the centralized and hierarchical-supervised integrated controls of EPS and ASS which using of multibody models were studied. In the centralized integrated control, taking into account there are many constraints and uncertainties in actual vehicle driving course, the MPC control strategy was designed; in the hierarchical-supervised coordination control, based on the full vehicle space multibody dynamics model, the sub-controller and the upper controller which supervises and coordinates the subsystems were designed. At the same time, applying of multibody dynamics models and the hierarchical-supervised coordination strategy, according to the motion coupling relationships between steering and braking systems, as well as steering, suspension and braking systems, respectively, the hierarchical-supervised coordination control of EPS/ABS and the three systems were studied. The simulation results show the effectiveness of integrated control and feasibility of applying multibody models to the integrated control.Based on the PXI hardware and LabVIEW software, a real-time hardware in the loop platform which provided with the data acquisition and logic control functions was created. In this platform, the vehicle hardware-in-the-loop test for the EPS power assisted control and the coordination control of EPS and ABS were carried out. The results show that the control strategy is reasonable. Also this test will lay the foundations of the actual product development, and improve the efficiency of the development.