Real‐time hybrid control of electrohydraulic active suspension

Abstract

Summary Electrohydraulic actuators are an attractive choice for active suspension, because these systems provide a high power‐to‐weight ratio. However, their dynamics are highly nonlinear. In addition, the use of one simple controller for both position and force is complicated, because there is a compromise between them in the case of active suspension. Most existing controllers do not efficiently fulfill the requirements, because only one state variable is considered. In this paper, we address these problems by developing a new hybrid controller for both position and force and implementing it in a real‐time test bench. Our goal is to control the vertical position of the passenger seat while tracking the force transmitted to passengers and keeping it within tolerable and comfortable limits. Therefore, the proposed controller is a combination of two controllers. Its flexible structure redirects the control signal to control the proper controlled state variable. The real‐time results of the newly designed hybrid controller are compared with those obtained using a classical proportional integral derivative controller, because this is the most widely used controller in the industry. As expected, the proposed controller demonstrates better performance in real‐time operation. Copyright © 2017 John Wiley & Sons, Ltd.

Nonfragile fault‐tolerant control of suspension systems subject to input quantization and actuator fault

“…In this study, the system parameters, such as m u , c s , c t , k s , k t , are assumed to be constant, which implies the model is simplified. Of course, the more complex controlled models by considering the parameter perturbation and nonlinear dynamics via different control strategies can be referred to References 2,3,5,6,8,10,11, and 32‐34. This study is focused on the nonfragile quantized control for SSs based on a relatively simplified model, and the developed design strategy can also be applied to the above models with more complexity, which would be further considered in our future work thus is omitted here.…”

“…However, the vehicle performance, such as the ride comfort, road holding stability, and maneuverability, generally conflicts with each other; therefore, when design the SS, considerable attention and effort have been paid for the control and optimization problem of these required suspension performances and realizing the trade‐off between them 1 . Among different types of SSs, the active suspension system (ASS) is the more attractive ones, due to its great potential in terms of improving vehicle ride comfort and road holding, and plenty of control policy has been developed, such as References 2‐13. Particularly, control is the relative concerned one due to its elegant characterization for ride comfort 11,14‐18 …”

Robust adaptive backstepping sliding mode control for motion mode decoupling of two‐axle vehicles with active kinetic dynamic suspension systems

“…Different from above studies, the proposed AKDSS only employ one nonlinear hydraulic actuator, which has the merit of energy efficient and convenient implementation. Electrohydrostatic actuator (EHA) has strong nonlinear characteristics, thus the advance control theory such as sliding mode control, backstepping control, and adaptive control and so on are applied to achieve nonlinear tracking control of EHA for active suspension. Guan et al proposed an adaptive sliding mode control for electrohydraulic system with considering nonlinear unknown parameters such as original volumes of cylinders, a good performance of tracking task is verified by the experimental results.…”

Improvement of ride quality for patient lying in ambulance with a new hydro-pneumatic suspension

“…Their passive suspensions, though adequate for the original vehicle, are unable to meet the driving requirement of the ambulance. Semi-active and active suspensions have been adopted to improve overall dynamic performance for both handling and ride comfort, [18][19][20][21] while the passive suspensions are still widely used due to inevitable limits of these semi-active/active suspensions, such as increased cost, uncertain reliability, power consumption, and inherent complexity. 22 , 23 The conventional suspension (CS) with anti-roll bars (ARBs) can improve the roll stability, while the ride comfort would be deteriorated as well.…”