• Journal of Biosystems Engineering
• /
• v.37 no.3
• /
• pp.148-154
• /
• 2012

Purpose: In order to improve road-friendliness of heavy vehicles, a fuzzy hybrid control strategy consisting of a hybrid control strategy and a fuzzy logic control module is proposed. The performance of the proposed strategy should be effectively evaluated using a hardware-in-the-loop (HIL) simulation model of a semi-active suspension system based on the fuzzy hybrid control strategy prior to real vehicle implementations. Methods: A hardware-in-the-loop (HIL) simulation system was synthesized by utilizing a self-developed electronic control unit (ECU), a PCI-1711 multi-functional data acquisition board as well as the previously developed quarter-car simulation model. Road-friendliness of a semi-active suspension system controlled by the proposed control strategy was simulated via the HIL system using Dynamic Load Coefficient (DLC) and Dynamic Load Stress Factor (DLSF) criteria. Results: Compared to a passive suspension, a semi-active suspension system based on the fuzzy hybrid control strategy reduced the DLC and DLSF values. Conclusions: The proposed control strategy of semi-active suspension systems can be employed to improve road-friendliness of road vehicles.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1275-1280
• /
• 2004

This paper presents the construction of an active suspension system of a one-wheel car model by using fuzzy reasoning. The car model is approximately described by a nonlinear two degrees freedom system subject to excitation from a road profile, and the active control force is constructed by actuating a pneumatic actuator, and the degradation of the performance due to the delay of the pneumatic actuator is improved by inserting a compensator. The fuzzy control is obtained by single input rule modules fuzzy reasoning, and the excitation from the road profile is estimated by using a disturbance observer. The experimental result shows that the proposed active suspension system much improves the performance in the vibration suppression of the car model.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.2 no.4
• /
• pp.27-38
• /
• 1994

In this paper, a simplified model of a hydraulic actuator system for a low-band type active suspension system is derived. To reduce the order of model, time constants of each chamber in hydraulic system are neglected except that of an accumulator. And the dynamics of a spool in the pressure control valve is regarded as a first-order system. The step response and the frequency response of the simplified second-order simulation model exhibit a good agreement with those of the actual system as well as those of the tenth-order simulation model. It is possible to simplify the tenth-order model to the second-order one. The low-band type active suspension model is built up by combining of a quarter car model test rig to testify the validity of the simplified model. The experimental results of suspension characteristics show that the simplified second-order hydraulic actuator model is reasonable to describe the dynamics of the actual hydraulic actuator system for a low-band type active suspension system.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1994.10a
• /
• pp.420-424
• /
• 1994

In this paper, an active suspension system considering the wheel hop is studied for a quarter car model. A LQ controller controls an active suspension system in which a vibration absorber is attached to the wheel axis. The vibration absorber is adopted to reduce the vibration near the natural frequency of the unsprung mass, and the LQ controller is used to control the vibration near the natural frequency of the sprung mass. The perfomance of the control system considering the wheel hop is compared with that of a LQ control system.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.783-788
• /
• 1990

Computer simulation is carried out for passive, active, and semi-active suspension system. Each RMS and frequency response to road profile input is calculated for comparison and evaluation of the performance. The vibration analysis and active control of the quarter model of a vehicle suspension is studied in order to evaluate the alternative control laws. This paper derives an optimal closed-loop feedback law for the semi-active suspension that justifies the clipped optimal approach.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1152-1157
• /
• 2005

This paper is concerned with the construction of an improved sliding mode control for the active suspension system of a one-wheel car model subject to the excitation from a road profile. The active control is composed of the equivalent and the switching controls where an improved sliding surface is proposed. The active control force is generated by operating a pneumatic actuator due to the control signal that constructed by measuring the state variables of the car model and by estimating the excitation from the road profile using the VSS observer. The experimental result indicates that the proposed active suspension system is relatively effective in the vibration suppression of the car model.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1107-1112
• /
• 1996

A semi-active suspension system with continuously variable damper is greatly expected to be mainly used in the future as a high-performance suspension system due to its cost-effectiveness, light weight, and low energy consumption. To develop the suitable control logic for the semi-active suspension system, the hardware-in-the-loop simulation is performed with the experimental continuously variable damper combined with a quarter-car model. The hardware-in-the-loop simulation results are compared for passive, on/off controlled, and continuously controlled dampers in the aspects of ride comfort and driving safety, assuming each damper to be installed on a vehicle.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.6
• /
• pp.967-975
• /
• 2010

There have been a lot of efforts on the improvement for the ride comfort and handling stability of the combat vehicles. Especially most of vehicles for military purpose have bad inertial condition and severe operating condition such as the rough road driving, and need a high mobility in the emergency status. It is necessary to apply the controlled suspension system in order to improve the vehicle mobile stability and ride comfort ability of crews. A feasibility study is performed on the application of the semi-active suspension system with a magneto-rheological controlled shock absorber for a $6{\times}6$ combat vehicle. First, the dynamic simulation model of the vehicle including the control model for the semi-active suspension system was executed. Based on this model, a hardware-in-the-loop simulation(HILS) system which has a semi-active suspension controller hardware was constructed. After full vehicle simulations were performed in virtual proving courses with this system, the semi-active suspension system was proven to give better ride comfort and handling stability in comparison with the conventional passive suspension system.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.295-298
• /
• 1996

In this paper, a self-tuning optimal control algorithm is proposed to retain the optimal performance of an active suspension system, when the vehicle has some time varying parameters and parameter uncertainties. We consider a 2 DOF time-varying quarter car model which has the parameter variation of sprung mass, suspension spring constant and suspension damping constant. Instead of solving algebraic riccati equation on line, we propose a neural network approach as an alternative. The optimal feedback gains obtained from the off line computation, according to parameter variations, are used as the neural network training data. When the active suspension system is on, the parameters are identified by the recursive least square method and the trained neural network controller designer finds the proper optimal feedback gains. The simulation results are represented and discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.513-517
• /
• 1995

In this paper, a relation of matrix Q in cost function to distances between the closed-loop and open-loop poles of a multi input controllable systems is studied. Futhmore, the state feedback gain with exact desired eigenvalues in the LQR is computed. The proposed scheme is applied to designing automotive active suspension control system for a half-car model and its performance is compared with the existing LQR control system design methodology.