Download or read book Dynamic Characterization of a Magneto rheological Fluid Damper and Synthesis of a Semi active Suspension Seat written by Xiaoqing Ma and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the point of view of suspension damper, semi-active dampers with only minimal power requirement could be applied to achieve variable damping to enhance suspension performance under complex vibration and shock environments. Magneto-rheological (MR) fluid based dampers offer significant potential for realizing semi-actively controlled variable damping with only minimal power. The MR-fluid dampers invariably exhibit considerable hysteresis, while the damping force varies with the intensity of applied electro-magnetic field and the nature of vibration in a highly nonlinear manner. A simulation model based on symmetric and asymmetric sigmoid functions is developed to fully characterize the properties of a MR-damper as function of excitation and control current. A comprehensive laboratory test program is undertaken to characterize the damping properties of a MR damper under wide ranges of excitations and control current. The essential fundamental features are identified for the modeling task, while the model parameters are identified using multi-parameter error minimization techniques. The validity of the proposed generic model is thoroughly examined by comparing the model response with the measured data under a wide range of excitations, particularly the force saturation and the hysteresis behaviour. An independent current function is further derived that could be integrated to reported regression-based hysteresis models to enhance their prediction abilities. From the results of the study, it is concluded that the refined Bouc-Wen and the proposed generalized sigmoid function model can fully characterized the nonlinear MR damping behaviour as function of applied current and excitation. A nonlinear analytical model of a pneumatic suspension seat including the motion limiting stops is developed for synthesis and analyses of the MR-damping control algorithms. The validity of the passive suspension seat model is thoroughly examined under various deterministic and random vibration excitations of varying intensities. The results suggest that attenuation of shock as well as vibration imposes difficulties design compromise of the passive damper. Owing to the strongly nonlinear properties of the suspension-seat and the MR-damper, such as hysteresis, saturation and end-stop impacts, a 'hi-lo' semi-active control algorithm is synthesized to realized modulation of the control current and thus the damping force following the skyhook control law. A continuous modulation function is further synthesized and integrated to ensure smooth transition between the 'hi' and 'lo' states. A relative position control is further introduced to limit the frequency and severity of shock motions caused by end-stop impacts. A set of performance measures is proposed to assess the characteristics of the semi-active and the resulting integrated controller under a wide range of excitations, including deterministic excitations of continuous and transient nature and random excitations of different vehicles. The potential performance benefits of the controller design are further investigated through a hardware-in-the-loop test and simulation program. The results are used to demonstrate the validity of the MR-damper and suspension seat models, and effectiveness of the control algorithm.

Download or read book Dynamic Characterization of a Magneto rheological Fluid Damper and Synthesis of a Semi active Suspension Seat written by Qing Ma Xiao and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling and Analysis of a Semi active Magneto rheological Damper Suspension Seat and Controller Synthesis written by Xiaoxi Huang and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whole body vibration in operational vehicles can cause serious musculo-skeletal disorders among the exposed workers. Consequently, considerable efforts have been made to protect vehicle operators from potentially harmful vibration. This thesis was aimed at the development of a semi-active suspension seat equipped with a magneto-rheological (MR) fluid damper. A damper controller was synthesized to minimize the vibration transmitted to the seated body and the frequency of end-stop impacts, which is known to induce high intensity vibration or shock motions to the seated occupant. A suspension seat was modeled by considering the kinematic non-linearity due to the cross-linkages and the damper link, while the cushion characteristics were linearized about the operating preload. The force-velocity properties of the MR damper were modeled by piecewise polynomial functions of applied current on the basis of the laboratory-measured data. The kineto-dynamic model of the suspension seat was thoroughly validated using the laboratory-measured responses under harmonic excitations in the 0.5 to 10Hz range. The performance characteristics of the passive suspension seat model were evaluated under different vehicular excitations in terms of frequency-weighted rms acceleration, vibration dose value (VDV), seat effective amplitude transmissibility (SEAT) and VDV ratio. These performance characteristics are also evaluated under amplified vehicular excitations in order to investigate the frequency as well as the potential suppression of end-stop impacts. The controller synthesis was realized in two stages: (1) attenuation of continuous vibration; and (2) suppression of end-stop impacts. Two different algorithms were explored in the first stage synthesis, which included a sky-hook control algorithm and a relative states feedback control algorithm. Each algorithm was further utilized in two different control current modulations. The performance potentials of each control synthesis were investigated using the 2 MATLAB Simulink platform under harmonic, transient, and random vehicular excitations in terms of SEAT and VDV ratio. One controller design (overall best suited for implementations) was subsequently implemented in a hardware-in-the-loop (HIL) test platform coupled with a MR-fluid damper mounted on an electro-hydraulic actuator that was linked to the HIL simulation platform. The semi-active suspension seat performance characteristics were further evaluated under different excitations using the selected control scheme. The results showed that the selected control scheme yielded SEAT and VDV ratio reductions in the 5 to 30% range depending upon the nature of excitations. The implementation of the second-stage controller, which was tested only by simulations, entirely eliminated the occurrence of end-stop impacts at nominal vibration level and attenuated the end-stop impact severity of three times amplified excitations by up to 10% . The results further suggested that the use of MR-fluid damper in suspension seat was most beneficial to city buses and class I earth moving vehicles amongst the selected inputs.

Download or read book Synthesis Characterization and Applications of Magneto Responsive Functional Materials written by Yancheng Li and published by Frontiers Media SA. This book was released on 2021-08-10 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis and testing of modified hydraulic semi active damper by magneto rheological approach written by Khedkar Yashpal Marutirao and published by Book Rivers. This book was released on 2024-02-24 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Syntheses and Analyses of Semi active Control Algorithms for a Magneto rheological Damper for Vehicle Suspensions written by En Rong Wang and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Syntheses and Analyses of Semi active Control Algorithms for a Magneto rheological Damper for Vehicle Suspensions written by Enrong Wang and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vehicle suspensions impose conflicting design requirements to satisfy the performance goals related to ride, handling and road holding. Semi-active damping suspensions, with their low cost and low power requirement, have been extensively investigated to achieve better compromises among different performance measures. The magneto-rheological (MR) fluid dampers offer superior potential to achieve rapid variations in the damping force and thus the wide bandwidth. The MR dampers, however, exhibit strong nonlinearities associated with force saturation and hysteresis, which affect the force-tracking performance of the controller in an adverse manner. This dissertation research focuses on characterization and modeling of the hysteretic force-velocity (F-v) characteristics of a MR-fluid damper, and analyses of different semi-active controller syntheses to achieve improved multi-objective vehicle suspension performance. The force-limiting and hysteresis properties of a prototype MR-damper are characterized in the laboratory as functions of applied magnetic field, and response and excitation variables. An asymmetric force generation algorithm is formulated and integrated into the command current circuit to achieve asymmetric force in compression and rebound from the symmetric damper hardware. The measured data are used to identify the low-speed pre-yield, post-yield, force-limiting and hysteretic force-velocity characteristics in both symmetric as well as asymmetric damping modes. A generalized analytical model of the MR-damper is developed using symmetric and asymmetric sigmoid functions. The validity of the proposed model is demonstrated under wide ranges of control current and excitations. A number of control syntheses are formulated to achieve semi-active modulation in drive current of the MR-damper, including four different on-off and "skyhook"--Based hi-lo, and "inverse-model"-based hi-lo and sliding-mode controllers. Continuous modulation (CM) and asymmetric damping force generation (ADFG) algorithms are proposed and integrated within the control policies to minimize switching transients in the symmetric and asymmetric modes.

Download or read book Insight into Magnetorheological Shock Absorbers written by Janusz Gołdasz and published by Springer. This book was released on 2014-12-27 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with magnetorheological fluid theory, modeling and applications of automotive magnetorheological dampers. On the theoretical side a review of MR fluid compositions and key factors affecting the characteristics of these fluids is followed by a description of existing applications in the area of vibration isolation and flow-mode shock absorbers in particular. As a majority of existing magnetorheological devices operates in a so-called flow mode a critical review is carried out in that regard. Specifically, the authors highlight common configurations of flow-mode magnetorheological shock absorbers, or so-called MR dampers that have been considered by the automotive industry for controlled chassis applications. The authors focus on single-tube dampers utilizing a piston assembly with one coil or multiple coils and at least one annular flow channel in the piston.

Download or read book Design Simulation and Fabrication of a Lightweight Magneto Rheological Damper written by Soroush Sefidkar-Dezfouli and published by . This book was released on 2014 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mountain biking has significantly evolved recently, thanks to utilizing cutting-edge technologies in mountain bicycle design and fabrication. In this research we study development of a semi-active suspension system using magneto-rheological (MR) fluid dampers instead of conventional oil based shocks. MR dampers are devices with magnetic field dependent damping characteristics.Low power consumption, high controllability, quick response, and high durability are among the major features of MR dampers. In this work we first investigate the damping characteristics of MR dampers to find out if characteristics comparable to the conventional shocks used in mountain bikes can be achieved. To this end,experimental tests were performed on an off-the-shelf MR damper. The results indicate that damping characteristics similar to the ones used in mountain bikes can in fact be achieved using MR technology.However, requirements such as small weight and wide dynamic range have to be addressed in designing a MR damper for mountain bikes. These considerations are studied in this thesis by formulating a simple design followed by a constrained optimization problem and designing the damper accordingly. Utilizing Finite element modeling and simulation tools are further utilized to fine tune and optimize the design.A prototype MR damper is fabricated after the above design steps are carried out.

Download or read book Design Semi active Suspension Using Magneto rheological Damper written by Muhamad Amzansani Abd Wahab and published by . This book was released on 2010 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focused on the development of semi- active suspension by using magneto-rheological damper. The MR damper is a type of damper that used MR fluid as working fluid which enables us to change damping force and setting of suspension without need to setting manually damper itself. It can be achieve by changing the current flow on it magnetic circuit.This thesis first introduces MR technology through a discussion of MR fluid and then by giving a broad overview of MR devices that is being developed. After giving the reader an understanding of MR technology and devices, MR damper basics are presented. This section includes a discussion of MR damper types, mathematical fundamentals, and an approach to magnetic circuit design. With the necessary background information covered, MR dampers for automotive use are then discussed. Then come to design part. By using specification same as Proton Waja passive damper, the model was develop by using SOLIDWORK software. The design used twin tube damper with same size of outer tube of OEM damper. The parameter like number of turn, length and diameter of the wire, current induced, magnetic field generated, head piston velocity, and force produced by MR damper was be calculated and discussed. The result show the damper produced 6475.441 Newton of maximum force when 3 ampere of current being applied to the damper. The force generated by damper at 0.5, 1, 1.5, 2, 2.5 and 3 ampere was plotted in a single graph versus piston head velocity in order to give better view of result.

Download or read book Design and Implementation of Energy Generated Magneto rheological Damper for Vehicle Suspension Systems written by Raju Ahamed and published by . This book was released on 2015 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magneto rheological (MR) fluid based dampers are very promising for semi-active or adaptive suspension control system which is filled with MR fluid. Its huge advantages attract the researchers to use it in more advanced application. MR damper's damping force can be controlled by changing the viscosity of its internal magneto-rheological fluids (MRF). However the requirement of external power source is one of the major concerns. Self-powered MR damper is one of the recent advancement which is accomplished only for double ended MR damper. In this work an energy generated mono tube MR damper has been designed and investigated with power generation which has a huge demand in the vehicle suspension system. This damper combines the advantages of energy harvesting (reusing wasted energy) and MR damping (controllable damping force). This multifunctional integration would bring great benefits such as energy saving, size and weight reduction, lower cost, high reliability, and less maintenance for the MR damper systems. The proposed MR damper model consists permanent magnet and coil combination of energy generation. Two magnetic fields are induced inside this damper. One is in the outer coil of the power generator and another is the piston head coils. A 2-D Axisymmetric model of energy generated MR damper is developed in COMSOL Multiphysics where it is analyzed extensively by finite element method and its hardware model is tested by Universal Testing Machine (UTM). The complete magnetic isolation between these two fields is accomplished here, which can be seen in the finite element analysis and damper characteristic analysis. The energy generation ability of the MR damper model is tested by UTM and oscilloscope combination and the maximum output voltage is measured around 0.8 volts by oscilloscope. Finally, experimental dampers characteristic analysis is performed by using RD-8041-1 MR Damper. These results are compared with the hardware model experimental results, which clearly validate the hardware model damper characteristic.

Download or read book Theoretical and Experimental Analysis of Mr Fluid Dampers written by Babruvahan P. Ronge and published by LAP Lambert Academic Publishing. This book was released on 2011-09 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Economical and effective damping system is the need of modern competitive industry to improve performance of the products in terms of comfort level, durability, etc. by minimizing vibrations. This motivated researchers to explore the advanced semi-active damping systems. The present work is focused on theoretical and experimental analysis of one of the semi-active systems, Magneto-Rheological (MR) fluid dampers. The study is initiated by a parametric study to understand the influence of various design variables on the performance parameters of a damper. To avoid the problem of local minima, an evolutionary algorithm, GA is used for optimal design. Further, 2D axisymmetric MR damper model is developed using FEM to study the magnetic properties in the fluid gap for different current inputs to the coil. Furthermore, the use of MR damper for vehicle vibration reduction is demonstrated using SIMULINK models of a typical vehicle and dynamic model of MR damper. Finally, experimental work on MR fluid, MR damper and quarter-car models with MR damper is carried out. Book is useful for academics, industry and research.

Download or read book Magneto rheological MR Damper for Landing Gear System written by Mahboubeh Khani and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Depending on the different sink speeds, angles of attack and masses; aircraft landing gears could face a wide range of impact conditions which may possibly cause structural damage or failure. Thus, in hard landing scenarios, the landing gear must absorb sufficient energy in order to minimize dynamic stress on the aircraft airframe. Semi-active control systems are the recent potential solutions to overcome these limitations. Among semi-active control strategies, those based on smart fluids such as magneto-rheological (MR) fluids have received recent attraction as their rheological properties can be continuously controlled using magnetic or electric field and they are not sensitive to the contaminants and the temperature variation and also require lower powers. This thesis focuses on modeling of a MR damper for landing gear system and analysis of semi-active controller to attenuate dynamic load and landing impact. First, passive landing gear of a Navy aircraft is modeled and the forces associated with the shock strut are formulated. The passive shock strut is then integrated with a MR valve to design MR shock strut. Here, MR shock strut is integrated with the landing gear system modeled as the 2DOF system and governing equations of motion are derived in order to simulate the dynamics of the system under different impact conditions. Subsequently the inverse model of the MR shock strut relating MR yield stress to the MR shock strut force and strut velocity is formulated. Using the developed governing equations and inverse model, a PID controller is formulated to reduce the acceleration of the system. Controlled performance of the simulated MR landing gear system is demonstrated and compared with that of passive system.

Download or read book Magneto rheological MR Damper Design for Off road Vehicle Suspensions with Flow Blocking Ability written by Riaan F. Meeser and published by . This book was released on 2015 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Semi active Suspension System Using a Magnetorheological Damper written by Abinav Suresh and published by . This book was released on 2016 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetorheological (MR) Fluid changes its yield strength when it is subjected to a magnetic field. When this fluid is used inside a damper, it has the ability to change the damping coefficients when it is acted upon by magnetic fields. In this experiment, a MR damper was tested on a shock dyno, where characteristics of the damper was found. Three parameters were changed during the course of the experiment, namely: electric current supplied through the solenoid of the damper, displacement amplitude of the piston and driving frequency of the motor. The results show that there was an increase in damping force when the three parameters were increased. Since the damper cannot be categorized as hard or soft using damping force, the damper and its configuration were represented in the terms of energy dissipated and equivalent damping coefficient. The trends of energy dissipated and equivalent damping coefficients were also compared with the change in electric current, displacement amplitude and driving frequency. Using the above results, a mathematical model was developed to predict the behavior of the MR damper. This model can be used in a control system, where a specific damping force and damping ratio is desired. A 'Single Degree of Freedom' (SDOF) system with a mass connected to a spring and a MR damper was studied. The response of the system was analyzed in the terms of transmissibility and phase angle. The results obtained were found similar to a passive suspension system with different damping ratios. A quarter car model was studied using the MR damper. A step input was chosen as road excitation and the responses of sprung and unsprung masses were studied. Sky-hook control strategy was utilized in the model to demonstrate the benefits of continuously changing the damping ratio in the system.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2007 with total page 960 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Controllable Suspension Design Using Magnetorheological Fluid written by Anria Strydom and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: