Do Xuan Phu

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 of a new adaptive fuzzy controller and its implementation for the damping force control of a magnetorheological damper

This paper presents a new adaptive fuzzy controller and its implementation for the damping force control of a magnetorheological (MR) fluid damper in order to validate the effectiveness of the control performance. An interval type 2 fuzzy model is built, and then combined with modified adaptive control to achieve the desired damping force. In the formulation of the new adaptive controller, an enhanced iterative algorithm is integrated with the fuzzy model to decrease the time of calculation (D Wu 2013 IEEE Trans. Fuzzy Syst. 21 80–99) and the control algorithm is synthesized based on the tracking technique. In addition, for the verification of good control performance of the proposed controller, a cylindrical MR damper which can be applied to the vibration control of a washing machine is designed and manufactured. For the operating fluid, a recently developed plate-like particle-based MR fluid is used instead of a conventional MR fluid featuring spherical particles. To highlight the control performance of the proposed controller, two existing adaptive fuzzy control algorithms proposed by other researchers are adopted and altered for a comparative study. It is demonstrated from both simulation and experiment that the proposed new adaptive controller shows better performance of damping force control in terms of response time and tracking accuracy than the existing approaches.

Design of a novel adaptive fuzzy sliding mode controller and application for vibration control of magnetorheological mount

This paper presents vibration control of a mixed-mode magnetorheological fluid-based mount system using a new robust fuzzy sliding mode controller. A novel model of controller is built based on adaptive hybrid control of interval type 2 fuzzy controller incorporating with a new modified sliding mode control. The interval type 2 fuzzy is optimized for computational cost by using enhanced iterative algorithm with stop condition, and a new modified switching surface of sliding mode control is designed for preventing the chattering of the system. The controller is then experimentally implemented under uncertain conditions in order to evaluate robust vibration control performance. In addition, in order to demonstrate the effectiveness of the proposed controller, two fuzzy sliding mode control algorithms proposed by Huang and Chan are adopted and modified. The principal control parameters of three controllers are updated online by adaptation laws to meet requirements of magnetorheological mount system which has two operation modes: flow mode and shear mode. It is shown from experimental realization of three controllers that the proposed control strategy performs the best under uncertain conditions compared with two other modified controllers. This merit is verified by presenting vibration control performances in both time and frequency domains.

Vibration control of a vehicle’s seat suspension featuring a magnetorheological damper based on a new adaptive fuzzy sliding-mode controller

This work presents a new design for adaptive fuzzy sliding-mode control based on two methodologies, namely H∞ control and sliding-mode control, and its control effectiveness. This is achieved by implementing a control scheme for vibration control of a vehicle with a seat suspension on which a magnetorheological damper is installed. The sliding surface of sliding-mode control is analysed by separation into two matrices: a Hurwitz-constants matrix and a constant matrix. These matrices are the basis for establishing the proposed control scheme combined with the H∞ technique. The control scheme consisting of the combination of H∞ control and sliding-mode control is reinforced by a new robustness function featuring an exponential function. In this work, a fuzzy logic model, which is well known to be an excellent model for uncertain dynamic systems, is integrated with the proposed control algorithm. The fuzzy logic model adopted in this work is an interval type-2 fuzzy model featuring fast computation of the output. The effectiveness of the proposed control scheme is evaluated through both computer simulations and experimental realization on a vehicle with a seat suspension which is equipped with a magnetorheological damper. In addition, in this work, two existing adaptive controllers are modified and implemented for comparative work with the proposed control scheme. It is shown that the proposed control scheme exhibits a much better vibration control performance than the two existing adaptive controllers do.

Rheological properties of bi-dispersed magnetorheological fluids based on plate-like iron particles with application to a small-sized damper

In this study, the rheological properties and an application of bi-dispersed magnetorheological fluid (MRF) based on plate-like iron particles are experimentally investigated. A bi-dispersed MR Fluid is prepared using two different micron-scale sizes of plate-like iron particles. In the absence of a magnetic field, the properties of the fluid are isotropic. Upon the application of a magnetic field, the magnetized particles form a chain aligned in the direction of the field, which promotes the appearance of a yield stress. The reversible transition from solid to liquid is the basic requirement of MR applications. Due to the anisotropy in the shape and formation of a less compact structure in the iron plate-like particles, weak sedimentation and good redispersibility of the proposed MR fluid are created. The physical properties of the proposed MR fluids are evaluated and applied to the design of a small-sized controllable MR vibration damper, which can be used for vibration control of a washing machine. The...

Design of a new adaptive fuzzy controller and its application to vibration control of a vehicle seat installed with an MR damper

This paper presents a new adaptive fuzzy controller featuring a combination of two different control methodologies: H infinity control technique and sliding mode control. It is known that both controllers are powerful in terms of high performance and robust stability. However, both control methods require an accurate dynamic model to design a state variable based controller in order to maintain their advantages. Thus, in this work a fuzzy control method which does not require an accurate dynamic model is adopted and two control methodologies are integrated to maintain the advantages even in an uncertain environment of the dynamic system. After a brief explanation of the interval type 2 fuzzy logic, a new adaptive fuzzy controller associated with the H infinity control and sliding mode control is formulated on the basis of Lyapunov stability theory. Subsequently, the formulated controller is applied to vibration control of a vehicle seat equipped with magnetorheological fluid damper (MR damper in short). An experimental setup for realization of the proposed controller is established and vibration control performances such as acceleration at the drivers seat are evaluated. In addition, in order to demonstrate the effectiveness of the proposed controller, a comparative work with two existing controllers is undertaken. It is shown through simulation and experiment that the proposed controller can provide much better vibration control performance than the two existing controllers.

Vibration control of a ship engine system using high-load magnetorheological mounts associated with a new indirect fuzzy sliding mode controller

In this work, a new high-load magnetorheological (MR) fluid mount system is devised and applied to control vibration in a ship engine. In the investigation of vibration-control performance, a new modified indirect fuzzy sliding mode controller is formulated and realized. The design of the proposed MR mount is based on the flow mode of MR fluid, and it includes two separated coils for generating a magnetic field. An optimization process is carried out to achieve maximal damping force under certain design constraints, such as the allowable height of the mount. As an actuating smart fluid, a new plate-like iron-particle-based MR fluid is used, instead of the conventional spherical iron-particle-based MR fluid. After evaluating the field-dependent yield stress of the MR fluid, the field-dependent damping force required to control unwanted vibration in the ship engine is determined. Subsequently, an appropriate-sized MR mount is manufactured and its damping characteristics are evaluated. After confirming the sufficient damping force level of the manufactured MR mount, a medium-sized ship engine mount system consisting of eight MR mounts is established, and its dynamic governing equations are derived. A new modified indirect fuzzy sliding mode controller is then formulated and applied to the engine mount system. The displacement and velocity responses show that the unwanted vibrations of the ship engine system can be effectively controlled in both the axial and radial directions by applying the proposed control methodology.

A new adaptive hybrid controller for vibration control of a vehicle seat suspension featuring MR damper

This paper presents a new hybrid controller which is a combination of three control schemes: fuzzy neural control, PI control and sliding mode control. The interval type 2 fuzzy model featuring updated rules via online is used in this study and in order to support the fuzzy model, a granular clustering method is applied to find groups of data related to the initial fuzzy rule. Then the output for fuzzy model is used for the PI-sliding mode controller. The combination of PI and sliding mode controls is carried out by H-infinity technique method which is rely on the modified Riccati-like equation. After developing the mathematical model, the proposed controller is applied to vibration control of a vehicle seat suspension featuring magneto-rheological (MR) damper. In order to demonstrate the effectiveness of the proposed controller, two different excitations of bump and random signals are adopted and corresponding vibration control performances are evaluated. It is demonstrated through both simulation and experiment that the proposed controller can provide much better than vibration control performance compared with the conventional controllers showing more robust stability.

A new magnetorheological mount featured by changeable damping gaps using a moved-plate valve structure

In this work, a new type of a magnetorheological (MR) fluid mount is proposed and its performances are experimentally investigated. The design of this MR mount is based on two operating modes of MR fluid: flow mode and shear mode. These modes are applied to the mechanism design consisting of two components: a fixed plate for applying the flow mode, and a moved plate for applying the shear mode of MR fluid motion. These plates belong to the valve-type structure of MR mount. The primary objective using the moved plate is to overcome the block-up phenomenon which frequently occurs in the conventional-type MR mount, in which there is no flow of MR fluid through the damping gap. In this research, a laboratorial fluid (MRF140) is used in the design and optimization of MR mount. This fluid features plate-like particles unlike the sphere particles. The yield stress of the fluid is measured as a function of the magnetic field and the theoretical analysis for the mount design is undertaken using the properties of the MR fluid, followed by design optimization. The objective function is concentrated on maximal damping force of the MR mount subjected to parameter constraints. Based on the results of optimization, the proposed MR mount is manufactured and tested for the performance evaluation. Vibration control capability and block-up phenomenon are investigated and compared between the proposed and conventional MR mounts.

Development of High Damping Magneto-Rheological Mount for Ship Engines

In this paper, novel configurations of a compact and high damping force engine mount featuring magnetorheological fluid (MRF) is proposed and analyzed. In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. Firstly, several configurations of the MR mount are proposed. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are then derived based on Bingham plastic behaviour of the MRF. Optimal design of the proposed MR mount is then considered. In the optimization, the objective is to find out the optimal structure of the MR mount that can generate a maximum damping force while the off-state force of the mount is constrained in such a manner that the force ratio of the mount is greater than a required value. Performance of the optimized MR mount is then evaluated based on finite element analysis and validated by experimental results.