Design And Control Of Electrical Active Suspension For Sport Utility Vehicle

With the development and progress of the times,people not only pursue the vehicle dynamic performance,but also begin to focus on the comfort and operational stability of the car.Their requirements are getting higher and higher.The vehicle suspension is an important factor affecting vehicle comfort and stability.Although most cars are using passive suspension,but due to the active suspension can take the initiative to improve the performance of the suspension on the car,its development will be an important direction for the development of the automobile technology in the future.In the current active suspension design study,most studies are biased in favor of active suspension control strategy or the structure of actuator.However,since the active suspension control strategy and the actuator are both complex system,the influence of each other is very big.This paper is divided into two parts.On the one hand,it makes a structure design for the Electro-Mechanical Actuator and simulation analysis for the electrical action system.On the other hand,the theory research of the combination of electric actuating system and the active suspension control strategy are made to analyze the performance characteristics of electric suspension.First of all,according to the relevant literature at home and abroad,to the electrical active suspension is determined as the focus of research objectives,and explain how it works.And then through the main parameters of the suspension system,the performance parameters of the Electro-Mechanical Actuator are determined.And the DC brushless motor is used by the slowdown mechanism to drive the ball screw rotation converting rotary motion into linear motion and transmitting force and displacement.The transmission and structure scheme are determined;the three-dimensional CATIA model and assembly drawings of Electro-Mechanical Actuator are drawn.Then,the suspension performance evaluation index and the AMESim simulation model of the input signals are determined such as random,step,square wave,and sine.Set the parameters and simulate in the time domain.Secondly,the electric actuator actuating system is divided into six parts,and the AMESim model of the electric actuator actuating system is established.According the result of simulation,make a research about the following behaviors and errors.It is shown that the designed electric actuator actuating system for the frequency less than 3HZ,the amplitude of 0.05 m sine and the mutation time greater than 0.12 s,the amplitude of 0.05 m step signal,the system response speed,the follow accuracy are able to meet the requirementsFinally,the principles of skyhook damping control,groundhook damping control and LQR control are introduced and their respective dynamics models and AMESim models are established.At the same time,the active suspension model and the electric actuator actuating system model are combined to obtain the electrical active suspension model.By using the AMESim and MATLAB/Simulink co-simulation method,do research on different road inputs signals.It is concluded that the three active control methods have improved the performance relative to the passive suspension.The larger the damping coefficient of the skyhook control,the better the effect of reducing the vehicle acceleration of the vehicle body.But when the value is too large,it will cause the performance of tire dynamic load deterioration and affect the stability of vehicle operation.In terms of unsprung mass,the control effect of the groundhook damping control is better than skyhook damping control,which can effectively improve the stability of the vehicle operation.However,for sprung mass,the control effect of the groudhook damping control is far worse than the skyhook damping control,which affects the ride comfort.The active suspension effect of LQR control is better than skyhook damping control and groundhook damping control,and the optimization of the three performance parameters is very balanced by using the 1HZ sine and the random signal of 0.15 s step as the pavement input.It is an ideal control method that using Electro-Mechanical Actuator for active suspension and LQR control method.It can not only effectively reduce the vehicle acceleration and suspension dynamic deflection,but also reduces the vibration of the tire.Thereby it improves the ride comfort of the vehicle while ensuring vehicle operational stability.