Active Suspension of Output Feedback Robust Control Based on LMI Approach

Volume 1 ◽  
2004 ◽  
Author(s):  
Zhiqiang Gu ◽  
S. Olutunde Oyadiji

Traditionally automotive suspension designs have been a compromise between the three conflicting criteria of road holding, load-carrying and passenger comfort. Active and semiactive suspension control methods have been considered as ways of increasing the freedom one has to specify independently the characteristics of load carrying, handling and ride quality. Consequently, these control methods have been enthusiastically investigated in the past decades. In this paper, active suspension control based on LMIs, including H∞ control and mixed H2/H∞ synthesis has been developed in this paper. The simulation results demonstrate that robust control method can suppress disturbance from road inputs, thus improving the ride comfort and maintaining the good road handling. The mixed H2/H∞ synthesis can provide both the robustness of H∞ control and the better performance of H2 (LQR) method.

Author(s):  
Rakesh Chandmal Sharma ◽  
Srihari Palli ◽  
M. Avesh ◽  
Neeraj Sharma

In the past, the magnetorheological (MR) suspension for railway vehicle has obtained great attention for the isolation of vibrations. This work presents a numerical approach to analyse skyhook and ground hook semi-active control methods for railway vehicle suspension. A 10 DoF model of the railway vehicle system is formulated for the comparative analysis between conventional passive and semi-active suspension control in the present study. The non-linear analysis is investigated in time and frequency domain for the sinusoidal excitations from the track.


2020 ◽  
Vol 10 (11) ◽  
pp. 3929 ◽  
Author(s):  
Hang Wu ◽  
Ling Zheng ◽  
Yinong Li ◽  
Zhida Zhang ◽  
Yinghong Yu

In this paper, after investigating the coupling effect in a permanent magnet synchronous in-wheel motor, a robust control method for active suspension of hub-driven electric vehicles (EVs) to enhance the performance of the in-wheel motor and the vehicle is proposed. Based on the electric vehicle model addressing the coupling effect between the electromagnetic excitation of the permanent magnet synchronous motor (PMSM) and the transient dynamics in EVs, the influence of the coupling effect on the motor and the vehicle performance is analyzed. The results reflect that the coupling effect in in-wheel motors intensifies the magnetic force oscillation, aggravates the eccentricity of the rotor, deteriorates the motor operation performance, and worsens the ride comfort. To suppress the magnetic force oscillation in motor and enhance the vehicle comfort, the active suspension system considering five aspects of suspension performance is introduced. Simultaneously, on the basis of Lyapunov stability theory, a reliable robust Hꝏ controller considering model uncertainties, actuator failure and electromagnetic force interference is designed. The simulation results reflect that the robust Hꝏ feedback controller can not only achieve better ride comfort, but also restrain the coupling effect in the motor. Meanwhile the other requirements such as the road holding capability, the actuator limitation, and the suspension deflection are also maintained. The proposed robust control method demonstrates a potential application in the practice of EV control.


2017 ◽  
Vol 20 (K5) ◽  
pp. 44-50
Author(s):  
Huyen Thi Thanh Dinh

This paper introduces a robust control method for car’s Macpherson active suspensions included uncertainties and exogenous disturbances. Based on saturated RISE control methodology, control force is guaranteed to be limited to a priori limit. Lyapunov stability analysis is exploited to prove control errors including vertical displacement, velocity and acceleration of the sprung mass asymptotically go to zero, so the ride comfort is improved. Simulations are performed to show the effectiveness of the proposed method in both time domain and frequency domain in comparison with the active suspension with PID controller, the semi-active suspension with a modified Skyhook control and the passive suspension.


2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Yechen Qin ◽  
Feng Zhao ◽  
Zhenfeng Wang ◽  
Liang Gu ◽  
Mingming Dong

This paper presents a comprehensive comparison and analysis for the effect of time delay on the five most representative semi-active suspension control strategies, and refers to four unsolved problems related to semi-active suspension performance and delay mechanism that existed. Dynamic characteristics of a commercially available continuous damping control (CDC) damper were first studied, and a material test system (MTS) load frame was used to depict the velocity-force map for a CDC damper. Both inverse and boundary models were developed to determine dynamic characteristics of the damper. In addition, in order for an improper damper delay of the form t+τ to be corrected, a delay mechanism of controllable damper was discussed in detail. Numerical simulation for five control strategies, i.e., modified skyhook control SC, hybrid control (HC), COC, model reference sliding mode control (MRSMC), and integrated error neuro control (IENC), with three different time delays: 5 ms, 10 ms, and 15 ms was performed. Simulation results displayed that by changing control weights/variables, performance of all five control strategies varied from being ride comfort oriented to being road handling oriented. Furthermore, increase in delay time resulted in deterioration of both ride comfort and road handling. Specifically, ride comfort was affected more than road handling. The answers to all four questions were finally provided according to simulation results.


Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5560
Author(s):  
Jarosław Konieczny ◽  
Marek Sibielak ◽  
Waldemar Rączka

In the paper authors consider the active suspension of the wheeled vehicle. The proposed controller consists of a sliding mode controller used to roll reduction and linear regulators with quadratic performance index (LQRs) for struts control was shown. The energy consumption optimization was taken into account at the stage of strut controllers synthesis. The studied system is half of the active vehicle suspension using hydraulic actuators to increase the ride comfort and keeping safety. Instead of installing additional actuators in the form of active anti-roll bars, it has been decided to expand the active suspension control algorithm by adding extra functionality that accounts for the roll. The suggested algorithm synthesis method is based on the object decomposition into two subsystems whose controllers can be synthesized separately. Individual suspension struts are controlled by actuators that use the controllers whose parameters have been calculated with the LQR method. The mathematical model of the actuator applied in the work takes into account its nonlinear nature and the dynamics of the servovalve. The simulation tests of the built active suspension control system have been performed. In the proposed solution, the vertical displacements caused by uneven road surface are reduced by controllers related directly to suspension strut actuators.


Author(s):  
Jialing Yao ◽  
Meng Wang ◽  
Yanan Bai

Automobile roll control aims to reduce or achieve a zero roll angle. However, the ability of this roll control to improve the handling stability of vehicles when turning is limited. This study proposes a direct tilt control methodology for automobiles based on active suspension. This tilt control leans the vehicle’s body toward the turning direction and therefore allows the roll moment generated by gravity to reduce or even offset the roll moment generated by the centrifugal force. This phenomenon will greatly improve the roll stability of the vehicle, as well as the ride comfort. A six-degrees-of-freedom vehicle dynamics model is established, and the desired tilt angle is determined through dynamic analysis. In addition, an H∞ robust controller that coordinates different performance demands to achieve the control objectives is designed. The occupant’s perceived lateral acceleration and the lateral load transfer ratio are used to evaluate and explain the main advantages of the proposed active tilt control. To account the difference between the proposed and traditional roll controls, a simulation analysis is performed to compare the proposed tilt H∞ robust control, a traditional H∞ robust control for zero roll angle, and a passive suspension system. The analysis of the time and frequency domains shows that the proposed controller greatly improves the handling stability and anti-rollover ability of vehicles during steering and maintains acceptable ride comfort.


Author(s):  
Amit Shukla ◽  
Jeong Hoi Koo

Nonlinear active suspension systems are very popular in the automotive applications. They include nonlinear stiffness and nonlinear damping elements. One of the types of damping element is a magneto-rheological fluid based damper which is receiving increased attention in the applications to the automotive suspension systems. Latest trends in suspension systems also include electronically controlled systems which provide advanced system performance and integration with various processes to improve vehicle ride comfort, handling and stability. A control bifurcation of a nonlinear system typically occurs when its linear approximation loses stabilizability. These control bifurcations are different from the classical bifurcation where qualitative stability of the equilibrium point changes. Any nonlinear control system can also exhibit control bifurcations. In this paper, control bifurcations of the nonlinear active suspension system, modeled as a two degree of freedom system, are analyzed. It is shown that the system looses stability via Hopf bifurcation. Parametric control bifurcation analysis is conducted and results presented to highlight the significance of the design of control system for nonlinear active suspension system. A framework for the design of feedback using the parametric analysis for the control bifurcations is proposed and illustrated for the nonlinear active suspension system.


2014 ◽  
Vol 663 ◽  
pp. 152-157
Author(s):  
Aghil Shavalipour ◽  
Sallehuddin Mohamed Haris

This paper consider the control of active automotive suspensions applying Mixed (H2/H∞) state-space optimization techniques. It is well known that the ride comfort is improved by reducing vehicle body acceleration generated by road disturbance. In order to study this phenomenon, Two Degrees of Freedom (DOF) in state space vehicle model was built in. However, the H∞ control method attenuates the agitation effect on the output while H2 is employed to improve the input of the controller. Linear Matrix Inequality (LMI) technique is employed to calculate the dynamic controller parameters. The outcome of the simulation revealed that ride comfort for the vehicle upgraded adequately by applying mixed H2/H∞ Control method for active suspension system, and also the mixed H2/H∞ Control method was more effective than the H∞ Control method.


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