لغزش چرخ در سیستم های ترمز ضد قفل مبتنی بر شبکه عصبی
Abstract
1- Introduction
2- Mathematical modeling
3- Control system design
4- Simulation results
5- Conclusion
References
Abstract
Anti-Lock Braking System (ABS) is a well-known technology for vehicle safety enhancement during hard braking. The wheel slip control has been a challenging problem due to a complex behavior of the tire and strong nonlinearity in a braking process. Furthermore, the system is subjected to unknown uncertainties that would arise from changing the vehicle parameters and un-model dynamics. Thus, it is required to design a nonlinear robust control law for ABS to overcome these problems. In this paper, a novel robust prediction-based controller for ABS is proposed that guarantees the stability against uncertainties. An optimal control law is firstly designed for ABS using nonlinear predictive method. Then, the unknown uncertainties are adaptively approximated utilizing a radial basis function neural network (RBFNN). The Lyapunov approach is employed to develop an update control law to determine the network weights. Finally, some simulations are conducted to examine the performance of the proposed control system for tracking the reference wheel slip in the presence of uncertainties in different maneuvers. Also, the performance of the proposed controller is compared with the conventional sliding mode controller (SMC) through simulation results.
Introduction
Many active safety devices have been developed to assist the driver to improve the vehicle safety during dangerous conditions. Among them, Anti-Lock Braking System (ABS) is a common wellknown active safety technology to control of automotive braking systems. In a hard braking situation, the wheels might lock and the braking forces fall to their sliding values and the lateral forces are reduced to almost zero [1]. In this manner, the stopping distance will be increased and the directional stability of vehicle in turning maneuvers will be lost. Hence, the longitudinal wheel slip has significant role in affecting the performance of braking, traction and stability control systems in ground vehicles. The ABS is known as a good solution to maintain the wheel slip at desired value and prevent the wheel from locking. As a result, the shortened stopping distance is obtained and the safety and the vehicle steerability are enhanced. In another application, the ABS is used in electronic stability control (ESC) systems to provide the required yaw moment for stabilizing vehicle lateral dynamics by differential braking strategy [2].