Research On Adaptive Fault Tolerant Control Of Automotive Active Suspension System

Automotive suspension systems are one of the main components of automobiles,and can be divided into passive suspension systems and active suspension systems.Active suspension system is the most widely used suspension system at present because of overcoming the shortcomings of passive suspension system.The performance of the suspension system has an important impact on driving safety and comfort.Adopting scientific methods to control the suspension system can improve the stability and comfort of the automobile.Due to the long-term driving of the automobile,some components may fail and age,or the controller,sensors,and actuators of the suspension system may usually fail,such as the actuator being stuck,gain changes,and constant deviation makes the automobile run away from the normal trajectory.This kind of fault is a random fault that occurs in actual driving,which can cause the instability of the controlled object during driving,and even cause a major traffic accident.This paper studies the fault-tolerant control method of the active suspension system actuator to ensure that the automobile system can run safely and stably when the actuator fails.This article focuses on the following two aspects:(1)Aiming at the problem of adaptive fault-tolerant control of active suspension systems with time-varying displacement and speed constraints,based on the analysis of the force of the half-car and the second law of Newton's mechanics,a dynamic model of the active-suspension system of the half-car is established.State variables build state space expressions.By constructing a time-varying obstacle Lyapunov function and adopting the Backstepping design method,a virtual fault-tolerant controller,a main fault-tolerant controller,and an adaptive law are designed to ensure that the displacement and speed of the vehicle body do not violate the constraint boundary and keep the automobile running smoothly.At the same time,the radial continuous function neural network is used to approximate the unknown continuous function in the system due to the uncertain body mass and other factors.The parameter estimation error is derived and used as an overlay on the adaptation to ensure the error convergence,thereby achieving the purpose of fast fault tolerance within the bounds.The space limitations of the active suspension system and the dynamic load of the tires are analyzed,and the effectiveness of the proposed fault-tolerant control method is verified by simulations of deviation faults and partial failure faults.(2)The adaptive fault-tolerant control of a quarter-car active suspension system with input saturation is studied.A mathematical model of a quarter-car is established based on Newton's law and Lagrangian modeling method.Based on device saturation problem,the radial basis neural network was used to approximate the unknown function of the active suspension system.When the actuator is not saturated,an adaptive fault-tolerant control scheme is designed based on the Backstepping design method.When the actuator is saturated,an adaptive fault-tolerant control scheme is designed based on the anti-saturation theory,and a first-order filter is introduced to correct the error value to increase the anti-interference ability of the fault-tolerant control.Through simulation research,the effectiveness of the proposed fault-tolerant anti-saturation control method is verified.