Min-Sang Seong

Vibration control of an electrorheological fluid-based suspension system with an energy regenerative mechanism

Abstract This work presents vibration control of a vehicle suspension system using a controllable electrorheological (ER) shock absorber activated by an energy generator without external power sources. The ER shock absorber has a rack and pinion mechanism which converts a linear motion of the piston to a rotary motion. This rotary motion is amplified by gears and subsequently activates a generator to produce electrical energy. The generated voltage is experimentally evaluated with respect to excitation magnitude and frequency of the ER shock absorber. After evaluating the damping force using the regenerated voltage, a quarter-car ER suspension model is established. A skyhook controller is then formulated and experimentally implemented to attenuate vibration using the regenerated energy. It has been demonstrated via experiment that suspension vibration under bumpy and sinusoidal road conditions is significantly controlled by activating the ER shock absorber operated by the proposed regenerative energy mechanism.

Integrated control on MR vehicle suspension system associated with braking and steering control

This article presents a hierarchy control strategy for magneto-rheological suspension system integrated with active braking and active front steering subsystems. This is proposed for the improvement of ride comfort and vehicle stability under different kinds of driving conditions. A nonlinear complicated full vehicle model which includes the longitudinal, lateral and vertical motions is established and combined with a modified coupling ‘Magic Formula’ tyre model. Subsequently, the global state identification and task assignment logic are formulated by adopting several driving conditions such as the straight driving and cornering state. A fuzzy control strategy is then used for the suspension system, while a sliding mode control technique is utilised for both braking and steering systems. In order to demonstrate the effectiveness of the proposed control methodology, control performances such as roll angle, yaw rate and vehicle trajectory are evaluated and presented.

A low sedimentation magnetorheological fluid based on plate-like iron particles, and verification using a damper test

This study presents a new kind of low sedimentation magnetorheological fluid (MRF). Its salient properties are evaluated using a small-sized damper. The proposed MRF is characterized to investigate the effect of plate-like iron particles on rheological properties such as yield stress and flow behavior. Plate-like micron size iron particles play an important role in improving stability against rapid sedimentation as well as in enhancing the value of the yield stress. This study also considers a bidisperse MRF because this can produce a higher yield stress compared with a monodisperse suspension. Since the field-dependent yield stress is the key factor in mechanical applications, the physical properties of the MRF proposed in this work are evaluated and applied to the design of a small-sized damper which can be used for vibration control in washing machines. In order to verify the smaller effect on the damping force due to the particle sedimentation, the field-dependent damping forces are measured under two different operating conditions; one is just after filling the MRF and another after operating for 48 h. The proposed MRF is shown to be very effective in reducing adverse effects due to particle sedimentation.

Design and vibration control of military vehicle suspension system using magnetorheological damper and disc spring

This paper proposes a new type of magnetorheological (MR) fluid based suspension system and applies it to military vehicles for vibration control. The suspension system consists of a gas spring, a MR damper and a safety passive damper (disc spring). Firstly, a dynamic model of the MR damper is derived by considering the pressure drop due to the viscosity and the yield stress of the MR fluid. A dynamic model of the disc spring is then established for its evaluation as a safety damper with respect to load and pressure. Secondly, a full military vehicle is adopted for the integration of the MR suspension system. A skyhook controller associated with a semi-active actuating condition is then designed to reduce the imposed vibration. In order to demonstrate the effectiveness of the proposed MR suspension system, a computer simulation is undertaken showing the vibration control performance of such properties as vertical displacement and pitch angle, evaluated for a bumpy road profile.

Damping force control of a vehicle MR damper using a Preisach hysteretic compensator

This paper presents damping force control performances of a magnetorheological (MR) damper via a new control strategy considering hysteretic behavior of the field-dependent damping force. In order to achieve this goal, a commercial MR damper, Delphi Magneride™ which is applicable to a high-class passenger vehicle is adopted and its field-dependent damping force is experimentally evaluated. The MR damper has two types of damping force hysteretic behavior. The first is velocity-dependent hysteresis and the other is field-dependent hysteresis. Since the magnetic field is directly connected with control input, the field-dependent hysteresis largely affects the control performances of the MR damper system. To consider the field-dependent hysteretic behavior of the MR damper, a Preisach hysteresis model is established and its first-order descending (FOD) curves are experimentally identified. Subsequently, a feedforward hysteretic compensator associated with the biviscous model and inverse Bingham model is formulated to achieve the desired damping force. The control algorithm is experimentally implemented and damping force controllability for sinusoidal and arbitrary trajectories is evaluated in terms of accuracy and input magnitude. In addition, vibration control performances of the MR suspension system are experimentally evaluated with a quarter-vehicle test facility.

Global integrated control of vehicle suspension and chassis key subsystems

Abstract This paper presents a new integrated control methodology for vehicle chassis subsystems associated with controlled suspension, braking system, and steering systems. In order to reflect the practical vehicle better, a non-linear complicated full-vehicle model which includes longitudinal, lateral, and vertical dynamics is established and combined with the modified non-linear tyre model. Then, a main objective-oriented hierarchical control strategy is proposed for global integrated control of chassis subsystems to improve the vehicle performance during different kinds of driving condition. The proposed hierarchical strategy consists of two layers. The upper layer is a system supervisory layer which is used to identify the vehicle states and to assign the task for each controllable subsystem based on their effective regions and the detected state signals of the system. The lower layer is the executive layer interfaced to actuators of the chassis subsystem. In this layer, different controllers which can be switched to a special vehicle state are designed by using fuzzy control and integral sliding-mode control methods. The effectiveness of the proposed control strategy is verified via computer simulations, showing the results of three typical driving conditions.

Vibration control of an MR vehicle suspension system considering both hysteretic behavior and parameter variation

This paper presents vibration control responses of a controllable magnetorheological (MR) suspension system considering the two most important characteristics of the system; the field-dependent hysteretic behavior of the MR damper and the parameter variation of the suspension. In order to achieve this goal, a cylindrical MR damper which is applicable to a middle-sized passenger car is designed and manufactured. After verifying the damping force controllability, the field-dependent hysteretic behavior of the MR damper is identified using the Preisach hysteresis model. The full-vehicle suspension model is then derived by considering vertical, pitch and roll motions. An controller is designed by treating the sprung mass of the vehicle as a parameter variation and integrating it with the hysteretic compensator which produces additional control input. In order to demonstrate the effectiveness and robustness of the proposed control system, the hardware-in-the-loop simulation (HILS) methodology is adopted by integrating the suspension model with the proposed MR damper. Vibration control responses of the vehicle suspension system such as vertical acceleration are evaluated under both bump and random road conditions.

Accurate position control of a flexible arm using a piezoactuator associated with a hysteresis compensator

In this work, position control of a one-link flexible arm is undertaken by considering the field-dependent hysteresis behavior of a piezoceramic actuator (piezoactuator in short). The proposed arm is controlled by two actuators: a motor mounted at the hub and a piezoceramic bonded to the surface of the flexible link. In the modeling process, two transfer functions: one from the input torque to output hub angle and the other from the input voltage to the output tip deflection are obtained. The hysteretic behavior of the piezoactuator is experimentally identified using the Preisach model, and the first-order descending (FOD) curves are obtained that are required to design a hysteresis compensator. After establishing the overall control block diagram for the position control of the flexible arm, a quantitative feedback theory (QFT) controller is designed by treating parameter variations and external disturbances as uncertainties. Subsequently, a hysteresis compensator that produces additional control input to the piezoactuator is designed to enhance the vibration control performance. An experimental realization of the proposed control scheme is undertaken and the effect of the hysteresis compensator on vibration control of the flexible arm is evaluated in the time domain.

Repulsive force control of minimally invasive surgery robot associated with three degrees of freedom electrorheological fluid-based haptic master

This paper presents a repulsive force feedback control in a haptic master–slave robot-assisted system for robot minimally invasive surgery. In general, the haptic master can provide position and force information for superior performance and reliability in master–slave robot-assisted interventions for a surgeon. In order to realize this potential, in this work three degrees of freedom electrorheological haptic master is adopted and associated with a four degrees of freedom slave robot. The haptic master featuring controllable electrorheological fluid is featured by a spherical joint mechanism and the slave robot is controlled by servomotors. After designing a user interface that is capable of providing force feedback in all the degrees of freedom available during robot minimally invasive surgery, the dynamic model of the haptic master is analyzed and the model parameters are identified to evaluate control performance of the haptic master on skin- and cancer-like tissues (palpation). Subsequently, the haptic architecture for robot minimally invasive surgery is established and experimentally implemented so that the reflection force for the object of the slave robot and the desired position for the master operator are transferred to each other. In order to demonstrate the effectiveness of the proposed system, repulsive force tracking control performances are evaluated and presented in time domain.

Experimental Performance Evaluation of MR Damper for Integrated Isolation Mount

This paper presents experimental performance evaluation of a magnetorheological(MR) damper for integrated isolation mount for ultra-precision manufacturing system. The vibration sources of the ultra-precision manufacturing system can be classified as follows: the one is the environmental vibration from the floor and the other is the transient vibration occurred from stage moving. The transient vibration occurred from the stage moving has serious adverse effect to the process because the vibration scale is quite larger than other vibrations. Therefore in this research, a semi-active MR damper, which can control the transient vibration, is adopted. Also the stage needs to be isolated from tiny vibrations from the floor. For this purpose, a dry-frictionless MR damper is required. In order to achieve this goal, a novel type of MR damper is originally designed and manufactured in this work. Subsequently, the damping force characteristics of MR damper are evaluated by simulation and experiment. In addition, the vibration control performance of the MR damper associated with the stage mass is evaluated.