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suspension-system
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A low-order H∞ controller design for an active suspension system via linear matrix inequalities
, Article JVC/Journal of Vibration and Control ; Volume 10, Issue 8 , 2004 , Pages 1181-1197 ; 10775463 (ISSN) ; Sadati, N ; Sharif University of Technology
2004
Abstract
We present an application of a new controller order reduction technique with stability and performance preservation based on linear matrix inequality optimization to an active suspension system. In this technique, the rank of the residue matrix of a proper rational approximation of a high-order H ∞ controller subject to the H∞ norm of a frequency-weighted error between the approximated controller and high-order H∞ controller is minimized. However, since solving this matrix rank minimization problem is very difficult, the rank objective function is replaced with the nuclear-norm that can be reduced to a semidefinite program, so that it can be solved efficiently. Application to the active...
Dynamics and Control of Seat Suspension Systems
, M.Sc. Thesis Sharif University of Technology ; Ghaemi Osgouie, kambeez (Supervisor)
Abstract
Suspension systems play a significant role in vehicles. They are responsible for providing ride comfort to the passengers and maintain car handling. Vibrations induced by the road can cause harmful effects on human body and this reveals the importance of designing and controlling the suspension system. Semi-active control is a reliable and safe method that has attracted a great deal of attention in the suppressing the car vibration. MR damper is a sample of semi-active control method. In most of the studies that have been done in literature the human body model has not been considered in designing the control strategy. In this study, a complete model of suspension system integrated with the...
Systematic Design of Chassis and Suspension System of a Multi-purpose Vehicle for Transportation, Repair and Cleaning Power Station Water Ways
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
In this thesis, overall design of a multi-purpose vehicle for transportation, repair and cleaning missions in hydro power station water ways during overhaul is presented. Design process is divided into several parts. The main challenges of the project and customer requirements are discussed first. A brief review of electric vehicles history is presented. The conceptual design including initial dimensional calculations, energy analysis and component selection are described in subsequent sections. Finally the structural and dynamic analysis of chassis and suspension system are carried out. To avoid pollution and life hazards to workers, a battery and electric motor drive system is utilized....
Design of car active suspension systems to obtain desired performance on reducing effect of road excitation on human health
, Article DETC2005: ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Long Beach, CA, 24 September 2005 through 28 September 2005 ; Volume 6 A , 2005 , Pages 383-390 ; 0791847438 (ISBN); 9780791847435 (ISBN) ; Ahmadian, M. T ; Sharifi Sedeh, R ; Sadati, N ; Sharif University of Technology
American Society of Mechanical Engineers
2005
Abstract
Advent of passenger cars has caused people to use them for more efficiency in their performance and wasting less time. Problems, however, still exist in them. For instance, since people travel with cars, their human bodies undergo in fatigue, restlessness, and sometimes health problems. Human body reaction under external vibration depends on the amplitude, frequency, and acceleration of the applied external excitation. These limitations which are usually announced by the bureau of standards imply the necessity of control of amplitude, vibration, frequency, and acceleration received by human body due to cars passing humps and bumps. In this paper, a quarter car model with active suspension...
Experiment of new laboratory prototyped magneto-rheological dampers on a light commercial vehicle using neuro-fuzzy algorithm
, Article JVC/Journal of Vibration and Control ; Volume 21, Issue 15 , 2015 , Pages 3007-3019 ; 10775463 (ISSN) ; Matbou, F ; Khayyat, A. A. A ; Sharif University of Technology
SAGE Publications Inc
2015
Abstract
Magneto-rheological (MR) fluids consist of magnetic particles in carrying fluid. One of the drawbacks in using MR dampers in laboratory work is their price. At present, there is a compelling need for the production of the laboratory scale of MR fluids to lower their production cost. In this study, to show that the MR fluid is an applicable prototyped laboratory scale of single ended and mono-tube, MR dampers with a prototyped MR fluid are presented. The main features of produced MR fluid and dampers are simplifying in constructing and their low cost. These dampers are useful for laboratory research work. To illustrate the validity of the MR fluids, using this fluid, four MR dampers are made...
Diffusion of Lipid and Protein Molecules in Cell Membranes
, Ph.D. Dissertation Sharif University of Technology ; Jalali, Abbas (Supervisor)
Abstract
Lipid membranes are fundamental constituents of cell membranes and are now used in lap-on-a-chip technology. Membranes in living cells contain a significant fraction of proteins, which undergo lateral random movements due to thermal fluctuations and shear forces imposed by the solvent fluid. Prominent natural and biotechnological systems where membranes are highly sheared include the plasma membrane of endothelial cells, and membranes used in biosensors for high throughput screening of drug candidates, and in water purification devices. In these systems membrane is in direct contact with the mainstream suspension flow, which is driven by pressure gradients. The efficiency and function of...
Multi-variable Optimization of Vehicle Seat Suspension Considering Human Body Model Using Spring-Damper Isolators and Genetic Algorithm
, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed (Supervisor) ; Vossoughi, Gholamreza (Supervisor)
Abstract
In recent years, the seat suspension system in commercial vehicles, industry, agriculture, transportation and … have been focused by researchers. Designing the spring-damper isolators for vehicle’s seat can be an achievable and suitable strategy to increase the comfort and decrease the risk of injuries in vehicles. In this research, the effect of vibrations due to road roughness has been examined by dynamic modeling of a vehicle in combination with the human body model. Thus by using spring-damper isolators and genetic algorithm, we try to optimize the performance of the system. Designing parameters includes the stiffness and viscosity of seat isolator and our target functions include the...
Semi Active Vibration Control of an Eleven Degree of Freedom Passenger Car Using Magnetorheological Shock Absorbers
, M.Sc. Thesis Sharif University of Technology ; Khayyat, Amir Ali Akbar (Supervisor)
Abstract
This thesis is presented to introduce a semi-active control of the suspension systems. The currently available semi-active damper technologies can be divided into two main groups. The first uses controllable electromagnetic valves and the second uses Magnetorheological (MR) fluid to control the damping characteristics of the system. A mass-spring model with eleven degrees of freedom, considering constant velocity for the car, is developed to model the suspension system. A semi-active vibration control system is presented to reduce the amplitude of automotive vibrations caused by the alteration of the road profile. The gravel road profile with Gaussian white noise as the road irregularity...
Vibration Isolation of One Degree of Freedom Systems by Magnetorheological (MR) Damper Under Random Excitation
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor)
Abstract
The effect of Vibration on the human body is considered as one of the limitations in design and use of HSCs at high speeds. One way to reduce the effect of vibration on the human body is to isolate deck vibrations from the crew by means of seat suspension system. This thesis has studied the effect of using an MR damper on the performance of seat suspension in vibration reduction. In fact, employing MR dampers in seat suspension systems enables us to change their damping. Using an MR damper makes it possible to control seat suspension by semi active control strategies. In this work, a number of proposed mathematical models of an MR damper were studied for numerical analysis and the most...
Vibration Isolation of Suspension System by Magneto-Rheological (MR)Damper
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor)
Abstract
Suspension system is one of the most influential components of vehicle in the area of stability and comfort. The suspension system is designed based on the use of the vehicle and stable characteristics. Obviously, being distant from the designed spots and applying various gates, its optimized performance is lost. Semi-active suspensions by changing their features get floating designed spots to be created and suspension system is always in optimum conditions through a suitable control. This research covers the efficacy of using damper Magneto Rheological which is called damper (MR) on the performance of vehicle suspension system in reducing vibrations. This damper is considered as a device in...
Design Optimization of an Ideal Steering Mechanism for Double Wishbone and MacPherson Suspensions
, M.Sc. Thesis Sharif University of Technology ; Fallah, Famida (Supervisor) ; Zohoor, Hassan (Supervisor)
Abstract
The steering system is very important in controlling the car. This requires to turning wheels at certain angles. These angles ideally follow the Ackerman geometry. But there is a difference between the real steering angle and the ideal geometry, which caused to steering error. This error depends on two factors, the steering mechanism and the vehicle suspension. Reducing steering error causes to reducing tire wear and increasing vehicle maneuverability at low speeds. In addition, the stability of the vehicle increases when crossing straight line and uneven roads. So far, mechanisms have been designed in accordance with the Ackerman geometry, but in these mechanisms used cam profile. Also...
Design of hydractive optimal suspension for a passenger vehicle
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 12 November 2010 through 18 November 2010, Vancouver, BC ; Volume 8, Issue PARTS A AND B , 2010 , Pages 351-359 ; 9780791844458 (ISBN) ; Asadi, N ; Yousefi, R ; Sharif University of Technology
2010
Abstract
In this study a hydractive suspension system is designed for a passenger car. By using a mathematical validated model with eight degrees of freedom for a vehicle which is equipped with hydractive suspension, optimal damping forces derived for suspension system on the base of optimal control theory which uses linear quadratic regulators for improving ride comfort of vehicle and saves vehicles stability at the same time. Existing limitations for applying damping forces and time lag of controlling component are considered. The results are being derived according to a bump excitation and nonlinearity effects of the hydractive suspension components. Simulation results for the hydractive optimal...
Design of an H∞-optimal FOPID controller using particle swarm optimization
, Article 26th Chinese Control Conference, CCC 2007, Zhangjiajie, 26 July 2007 through 31 July 2007 ; October , 2007 , Pages 435-440 ; 7900719229 (ISBN); 9787900719225 (ISBN) ; Masoud, K. G ; Nasser, S ; Sharif University of Technology
2007
Abstract
This paper proposes a novel method to design an H∞-optimal Fractional Order PLD (FOPLD) controller with ability to control the transient, steady-state response and stability margins characteristics. The method uses particle swarm optimization algorithm and operates based on minimizing a general cost function. Minimization of the cost function is carried out subject to the H∞-norm; this norm is also included in the cost function to achieve its lower value. The method is applied to a phase-locked-loop motor speed system and an electromagnetic suspension system as two examples to illustrate the design procedure and verify performance of the proposed controller. The results show that the...
Low-order H∞ controller design for an active suspension system via LMIs
, Article IEEE Transactions on Industrial Electronics ; Volume 53, Issue 2 , 2006 , Pages 554-560 ; 02780046 (ISSN) ; Sadati, N ; Sharif University of Technology
2006
Abstract
An application of a new controller order reduction technique with stability and performance preservation based on linear matrix inequality optimization to an active suspension system is presented. In this technique, the rank of the residue matrix of a proper rational approximation of a high-order H∞controller subject to the H∞-norm of a frequency-weighted error between the approximated controller and the high-order H∞ controller is minimized. However, because solving this matrix rank minimization problem is very difficult, the rank objective function is replaced with a nuclear-norm that can be reduced to a semidefinite program so that it can be solved efficiently. Application to the active...
Application of car semi- Active suspension systems to achieve desired performance on decreasing effect of road excitation on human health
, Article DETC2005: ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Long Beach, CA, 24 September 2005 through 28 September 2005 ; Volume 6 A , 2005 , Pages 375-382 ; 0791847438 (ISBN) ; Ahmadian, M. T ; Abdollahpour, R ; Sadati, N ; Sharif University of Technology
2005
Abstract
Using passenger cars for daily traveling include advantages and disadvantages simultaneously; this daily traveling causes variety of road excitations in the form of vibration with different amplitude and acceleration to be imposed on body. Exceeding the standard limitations of these parameters results in fatigue, restlessness, and health problems. In this paper, a quarter-car model with semi-active suspension system is considered and three control approaches are applied to reduce these parameters in the limit of standard. Results show adaptive fuzzy optimal controller has better performance compared to others in controlling the critical health parameters, and can be easily used in future...
Multi-Objective Control of an In-Joint Semi-Active Suspension System with Energy Harvesting Capability Using Neural Network
, M.Sc. Thesis Sharif University of Technology ; Sayyaadi, Hassan (Supervisor)
Abstract
The basic type of suspension systems, which is known as passive suspension systems, creates a balance and compromise between the two goals of ride comfort and road holding. In order to improve the performance of the suspension system, the use of active actuators has been considered. However these actuators require energy and control strategies. To supply the required energy, recovering the energy of vehicle vibrations can be a solution. Therefore, ride comfort, keeping the wheels in contact with the road and the amount of recoverable energy are three important control objectives for modern active and semi-active suspension systems. The control of these systems is considered a challenging...
Design, analysis and manufacturing a double wishbone suspension system with variable camber angle by pneumatics mechanism
, Article ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011 ; Volume 7, Issue PARTS A AND B , 2011 , Pages 477-483 ; 9780791854938 (ISBN) ; Mokhlespour, M. I ; Keshavarzi, A ; Hoviat Talab, M ; ASME ; Sharif University of Technology
2011
Abstract
The accuracy of multi dimensional simulation of vehicle dynamics has been significantly increased for both passive and active vehicles which are equipped with advanced electronic components. Recently, one of the subjects that has been considered is increasing the car safety in design. Therefore, many efforts have been done to increase vehicle stability especially during the turn. It is also very important in three wheel car. One of the most important efforts is adjusting the camber angle in the car suspension system. Camber angle as well as the vehicle stability has major effects on the wheel slip, reducing rubber abrasion, acceleration and braking. Since the increase or decrease in the...
Vibration control of vehicle suspension system using adaptive critic-based neurofuzzy controller
, Article 2009 6th International Symposium on Mechatronics and its Applications, ISMA 2009, Sharjah, 23 March 2009 through 26 March 2009 ; 2009 ; 9781424434817 (ISBN) ; Rahaeifard, M ; Alasty, A ; Sharif University of Technology
2009
Abstract
This paper presents an active suspension system for passenger cars, using adaptive critic-based neurofuzzy controller. The model is described by a system with seven degrees of freedom. The car is subjected to excitation from a rode surface and wheel unbalance. The main superiority of the proposed controller over previous analogous fuzzy logic controller designed approaches, e.g., genetic fuzzy logic controller, is its online tuning characteristic and remarkable reduced amount of computations used for parameter adaptation, which makes it desirable for real time applications. Considering the simplicity of this controller and its independence from the system model, this control method has the...
Design and Manufacturing of Left Ventricular Assist Device for Patients Undergoing Cardiac Surgery
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor) ; Firouzbakhsh, Keikhosrow (Supervisor)
Abstract
The heart is a powerful muscle whose primary function is to pump blood into the body. many cardiac patients reach a stage that can no longer be kept function of their heart to a satisfactory level by using medication thus doctors undergo surgery. The common problem occurs to most patients undergoing cardiac surgery is that after the surgery, the patient's heart during a short period of time is unable to supply blood with the flow rate and pressure required for all organs, especially the end organs of the body. In this conditions, ventricular assist device help the patients. These devices are used parallel with patient’s heart and supply the large portion of blood that patient’s body needs....
Semi Active Vibration Control of a Passenger Car Using Magnetorheological Shock Absorber
, M.Sc. Thesis Sharif University of Technology ; Zabihollah, Abolghasem (Supervisor)
Abstract
This project is intended to introduce a semi-active control for suspension systems of passenger cars wherein, in addition to usual dampers, the damper using Magnetorheological (MR) fluid instead of ordinary oil is used. In order to model the suspension system, a mass-spring model with eight degree-of-freedoms without considering the effect of car velocity is developed. A semi-active vibration control is presented to reduce the amplitude of automotive vibration caused by the alteration of road profile. In order to design a suitable control mechanism, first, an optimal control algorithm, Linear Quadratic Regulator (LQR) and Linear Quadratic Gaussian (LQG), are used to control the system;...