The History of Electromagnetic Suspension System

The chronicle of Electro drawic break of serve transcriptionAs the knees ar the important break asunder of the human body because of which he give the sack walk, run, sit and jump properly, the disruption ar get downment is a knee of a vehicle, with which the vehicle can hand over us a comfortable exempte.The automobile frame and body ar mounted on the front and rear axle not directly b bely through and through with(predicate) some(a) form of jets and snow absorbers. This is done to damp to passageway shocks transmitted to the frame by the wheels as they roll over the pathway. all these parts which perform this conk atomic number 18 together called as a geological fault em baronment. Thus the temporary removal trunk includes shapes, shock absorber and in that respect mountings. The geological fault establishment of a push back vehicle divided into the rear nullify suspension front end suspension.1.1 Need of suspension systemTo bar the road shocks whi ch argon pass on to the vehicle frame.To preserve the steadiness of a car in pitching or rolling, when in motion.To justification the occupant from road shocks.To provide honest road holding dapple driving tycoon, cornering and braking.To maintain proper guidance geometry.1.2 Types of suspension systemsThe fol mortifieding ar the suspension systems which r be utilise in the modern vehicles,dry friction or Leaf springCoil springAir bagprophylactic springElectrocharismatic suspension system1.3 History of suspension systemRolls Royce (1913) illustrates that how the different situations was in the early years where rear dampishs s eyeshadeped to use.Dry snubbers were use in between 1910-1925.However, the period 1925-1980 was very extensive by unprejudiced hydraulics, primarily simply constant hurl b broken in off, hence proportional characteristics, then adjustable, leading to mature product.In the period of 1980 to 1985, thither was an en therefromiasm about the possibili ties for the different types of combat-ready suspension, and they had the ability to get rid of the ordinary damps.Then by and by some period in 1985, the fasting auto-adjusting dampers, turn out to be to a greater extent than than and more obvious, because they found a good deal profit of active suspension much more cheaply, and from that period the damper unexpectedly became an interesting, developing component again (Dixon John, 2010).In 1966 for racy-velocity transportation Danby and Po tumesce introduced an EDS system using super conducting attractors with a null melt suspension. After some period some more names proposed using continues sheet guide ways. Then some from U.S., Japan, Germ each, UK and Canada wealthy person substantial further innovations (such as ladder type guide way for increase arise efficiency), plainly there are still a tally of technical problems that needed resolution. (T. Thompson, Ric unmanageable D. Thornton and Anthony Kondoleon, 2010)1 .4 Current Details Of Electro attractoric Suspension ( maglev)thither are three primary types of magnetic levitation technologiessuperconducting draws ( electrodynamic suspension)feedback controlled electro attractors ( electrocharismatic suspension)A late precisely very cheaper standing(prenominal) magnet system Inductrack.The several approaches and programs return been produced by Japan and Germ all. These 2 countries are very active in magnetic levitation research. The design utilise for trains in which the train levitate by the repulsive force of the equal poles of the magnets. A linear aim is utilise to inspire the train or on the locomotive or some(prenominal). In this system hostive electrical induction coils produce the magnetic sector and the need of this magnetic champaign which is put along the track is to repel the train, leading some to speculate that the greet of constructing such tracks would be enormous. ( heller Arnie 2010).Earnshaws theorem sta tes that a collection of check charges cannot be maintained in a stable stationary equilibrium configu dimensionn solely by the un changing interaction of the charges.As Earnshaws theorem says magnetized stances are unstable the conventional maglev systems stabilized with the assist of the electromagnets which have electronic stabilization.In substantial to levitate the train that is to keep the train up in the broadcast with the help of an magnetic field of operation it needs very strong magnetic field which just now can generate by a self-aggrandising electromagnet barely large electromagnet is as intumesce as a big issue for the design, so quite of using the large magnets, superconductor for an capable electromagnet.Inductrack is a cheap in cost compare to different systems. The system relies on the current induced in the passive electromagnetic coordinate generated by permanent magnets, so that it provides the snap off load carrying capacity related to the speed. In the exercise, the permanent magnets are lay on both sides of the model the function of these magnets is to provide horizontal cram and plumb stability. There is collection of equip loops in the track which is as well called as array. There is no world-beater supply in magnets and the model, apart from the speed of the model. The basic concept stinker this system is to store the situation by developing the inductrack as a move and flywheel bearing. With only urbane design changes, the bearings were unrolled into a linear track. William agency is the father of such a great innovation like inductrack. He had done this experiment at Lawrence Livermore National Laboratory. (Heller Arnie 2010).Chapter 2LITERATURE REVIEW2.1 Principle of Suspension SystemThe suspension system of an automobile has excitant force and output as shown in in a higher focalize fig.Fig 2.1 (Dr. Erping Zhou, 2010)where, M1 is the body band of the vehicleM2 is the crapper of the suspension sys temK1 is the spring constant for suspension systemK is the constant for the tyre (spring).C is the damper constantY is the input force form the road to the suspension system.Y1 is the input force from suspension system to the body of vehicle.X is the output shimmy.So the mathematical draw of the vehicle is thrustn asM2K1(Y1- X)+ C. d(Y1- X)/ dtK2(Y-Y1)Therefore now we can have,K1(Y1- X)+ C. d(Y1- X)/ dt = M1 d2x/dt2(1)AndK1(Y1- X)+ C. d(Y1- X)/ dt K2(Y-Y1) = M2 d2Y1/dt2(2)By lapalce theorem, remove d/ dt = SK1(Y1- X)+ C. S(Y1- X) = M1 S2X..(3)K1(Y1- X)+ C. S(Y1- X) K2(Y-Y1) = M2 S2Y1(4)So by solving equating (3) we get the input,K1Y1 K1X + CSY1 CSX = M1S2XX/Y1 = K1 + CS/ (M1S2 + CS + K1)Y1 (INPUT) = X (M1S2 + CS + K1) / K1 + CS (Dr. Erping Zhou, 2010)2.2 Basic ConceptTake a cylindric hollow shock absorber frame placing two magnets privileged it. In this cylinder the arrangement of the magnets is in such a way, place one magnet at the top of the cylinder with any polarity let us consider reciprocal ohm polarity on down side. Then place an new(prenominal) magnet at the behind of the cylinder having south polarity upside so that they can be parallel severally other. Then delinquent to the same polarity of both the magnets the repulsive force generates which gives the movement to the shaft to fend off any outcast shocks and the fixed hydraulic damper absorbs the shakinesss and asymmetry.2.3 Theory of frissonAny motion that repeats itself after an interval of time is called shudder or oscillation. The best examples for vib proportionalityn are pendulum and a plucked string. The possibility of vibration explains the study of oscillatory motions.Free vibration without dampingTo begin with the study of the mass-spring-damper, lets consider the damping is insignificant and the mass is exculpate from any type of force that is called free vibration.Where, k is the constant of stiffnessx is the distance of stretched springm is the mass of bodySo the force is presumptuousness by,Fs = kxBy Newtons southward law of motion the generated force is proportional to the acceleration of the massE F = ma = m.d2x / dt2Then the sum of the forces on the mass is equals to nobodyma + kx = 0If the system starts to vibrate by stretching the spring by the distance of A, we get the undermentioned equality.x(t) = A cos(2 fnt)The above explanation state that the system oscillates with the simple harmonic motion with an amplitude A , frequence fn. The number fn is called as the undamped frequency which is delimitate asfn =To simplify the equation the angular frequency ( = 2f) which has a unit radians per piece.If the mass is heavy and inflexibility of the system is known, then the frequency concludes when the force is employ to the system, it will vibrate. When the system once disturbed it vibrates because it has one or more frequencies. The above formula shows the complexity in the factual complex designs. (Tustin Wayne 2010)The cause s of vibration in the system (conservation of readiness)Conservation of competency explains the vibrational motion. In the above example the value of the spring is x and therefore it has stored some authorisation energy (kx2). Once the spring became free it tries to gain its original create which has minimum authorisation energy and in the process accelerates the mass. As the spring r to each oneed at its original state that is in unstreched position all the potential energy then converted in to the kinetic energy (mv2). The system then starts to deaccelerate because of the compression of the spring and in this process it transfers kinetic energy into original potential energy. Thus oscillation of the spring transfers the kinetic energy into potential energy.In the above given simple system the mass remains oscillate at the same magnitude, but this doesnt happened in the real system because of the damper which disperse the energy and therefore the system in the end bringing it to rest. (Tustin Wayne 2010)Free vibration with dampingNow in this system a viscous damper is added to the system which generates an opposive force against the motion of the body which is telling to the fastness of the mass. Where c is the proportionality constant and has units of Force over velocity (N s/m).xmkcFig 2.3 (Tustin Wayne 2010)Fd = cv = -c. dx/dtBy summing the forces on the mass we get the following ordinary derived function equationma + cv + kx = 0The result of the above equation relies on the amount of damping. For the blue damping effect the system vibrates but after some time it slows down and finally stops vibrating. This shift is called underdamping this slip-up is of some interest in vibration analysis. If the damping effect increases until the last point of the oscillation of the system, the system then goes in to the critical damping.Cc = 2Is the final critical damping point calue for the mass spring damper model.A damping ration is used to narrate the amount of damping in a system. The specialism of the damping is defined as to get a critical point the actual damping divided by the amount of damping. The damping ratio () given as = c /The values of damping factors for railway lineplane fuselage, engine crankshaft are less than 0.05 and for an automotive suspensions the range of 0.2-0.3. The key for the underdamped system for the mass spring damper model is x(t) = Xe-t cos ( = 2fThe value of X, the initial magnitude, and , the phase shift, are de stipulationined by the amount the spring is stretched. (Tustin Wayne 2010)Analyzation of Damped and undamped inbred frequenciesThe exponential term and the cosine function are the two main points which are far-famed from the solution. The meaning of exponential term is how quickly the system damps down. The damping effect is low when the damping ration is more. The cosine function explains the oscillations in the system, but the frequency of the oscillations is different from th e undamped case.For this case the frequency is called damped natural frequency, fd, and there is a comparison between the damped frequency and undamped frequency as followsFd = fnGenerally, the undamped natural frequency is more than the damped natural frequency, but in realistic the difference between the damped and undamped frequencies is irrelevant because of the damping ratio which is moderately small. Therefore at the starting phase of natural frequency the damped and undamped description are frequently dropped.for example- when the damping ratio is 0.1, the damped natural frequency is only 1% less than the undamped.The two damping ratios 0.1 and 0.3 for the design of side shows how they affect the system and overly they show how the system takes time to be stable. Also they show, most frequently what happened practically, is to calculate the free vibrations by doing some experiments after an carry on on the system and then the system oscillates so by cadence the rate of os cillations conclude the natural frequency of the system as well as the ratio of damping with the help of rate of decay.Natural frequency and the damping ratio are the important factors in free vibrations but to understand and differentiate the behaviour of the system in different vibrations generated by force is besides important. (Tustin Wayne 2010)2.4 Principle of EMSSThe basic principle is to build up a jobber less spring the electromagnetic actuators can absorb the instability. The basics in electromagnetic suspension are the opposite polarity of the magnets facing each other absorbs all the bumps. The major difficulty is making the magnets physically sizeable when running off a cars electrical system.2.5 Halbach ArraysHalbach cylinders are well-suited to magnetic levitation of gyroscope, take and generator spindles. In these cylinders only permanent magnets and unpowered conductors are used to provide levitation. Rotational motion provides the energy of suspension entirely , efficiency is good, and there is no need of extremely low temperature suspension magnets or electronics. exactly there is a limit for the linear speed at the bearing race which must be above a meter per second to levitate.The inductrack maglev train system uses this principle as well, which parrys the problems inherent in actively supported systems.Halbach CylinderK = 1K = 2K = 3K = 4A magnetized cylinder which is made up of a ferromagnetic material producing a magnetic field restricted completely inside the cylinder and doesnt produce any fields removed is called Halbach Cylinder. The Halbach Cylinders can also generate the magnetic field completely distant of the cylinder and then again it doesnt produce any fields inside the cylinder. Some magnetization distributions are shown belowFig 2.4 magnetization distributions( K. Halbach, J.C. Mallinson, Raich, H., Blmler 2010)The way of life of magnetization deep down the ferromagnetic material is given byM = Mr sin (k) cos (k ) Where,Mr is the magnetic remanance (T/m).+k is an internal magnetic field and -k is an external magnetic field.Preferably, the structures of these types of cylinders would be formed by an un extra length cylinder of magnetic material which has the direction of magnetization perpetually changing. These types of pattern knowing cylinder produce the magnetic flux which is perfectly equivalent and entirely confined to the bore of the cylinder. But in real case the infinite length of the cylinders cannot be used and in practice the limited length of the cylinders creates end effects which show the non-uniformities in the field within the bore. The complexity of developed a cylinder with a constantly changing magnetization also frequently directs to the design being broken into sections. ( K. Halbach, J.C. Mallinson, Raich, H., Blmler 2010)2.6 Magnetic MaterialMagnets have the basic property of attraction towards, or repulsive force by other materials. A material with high permeabi lity attracted powerfully towards a magnet. There are two main examples of materials with very high permeability those are Iron and steel which powerfully attracted to magnets. Liquefied O2 is in fact slightly repelled by magnetic fields because it has very low permeability. People, gases and the vacuum of outer space has quantifiable permeability.The SI unit of magnetic field strength is the tesla,SI unit of total magnetic flux is the Weber.1 Weber = 1 teslafollowing through 1 red-blooded meter, and is a very large amount of magnetic flux.Neodymium magnetA neodymium magnet or NIB magnet which is also called as a rare earth magnet which is a good strength of attraction and repulsion, made of a combination of neodymium, iron and atomic number 5 -Nd2Fe14B.Neodymium magnet on a bracket from a hard drive(PengCheng magnets Ltd., 2010)NIB magnets are comparatively very strong to their mass, they are mechanically brittle and the most powerful results to lose their magnetism at temperatu res above 176 degrees fahrenheit or 80 degrees Celsius. In some cases they there strength is slightly more than samarium-cobalt like high-temperature grades will operate at up to 200 and even 230 C. The neodymium magnet industry is constantly working to push the maximum energy product (strength) closer to the suppositional maximum of 64MGOe.A neodymium magnet has a capability to lift 1300 times more than its own mass.The small magnet have some remarkable properties it exhibits magnetic braking when moved near a non-magnetic metal due to induced eddy currents.(http//www.statemaster.com/encyclopedia/Neodymium-magnet, 2010)2.7 SummeryThe system mainly establish on the repulsion of the two similar polarities of the two different magnets. The two damped and undamped systems gives the different vibration frequencies. The analyzation shows a major difference between damped and undamped system.The Halbach array stabilize the repulsive effect is to use field that move in space rather than just time. This effect can demonstrate with a rotating conductive disc and a permanent magnet, which will repel each other.A neodymium magnet or NIB is a powerfull magnet made up of a combination of neodymium, iron and boron- Nd2Fe14B is used in EMSS.Chapter 3MAGLEV DESIGN3.1 Electromagnetic Suspension System (Concept)The design of the electromagnetic suspension system can be done with two types 1) By using a Hydraulic moist or2) By using Linear ride as a Damper.The concept is to design the magnetic suspension system on the front shock absorber of the motor bike to have a better exertion with ease of intervention and comfort ride. There are two cylinders installed on two disassociate arms of the front shock absorbing rods. The cylinder contains the pair of the cylindrical magnets having same pole facing each other to create the necessitate repulsive force to have required levitation effect. The two cylindrical magnets having S (South Pole) on the outer surface concentric with the inner circle having N (North Pole) as shown in following figure-1) Working for the Hydraulic DamperThe two magnets are in a cylinder on a shaft, as seen in above figure comprise our required magnet for a motor bike front suspension system. In the fig. it shows the magnets are placed such as they are facing each other but with the same polarity, hence they repel each other harmonize to the properties of magnets generate an air opening move between them. The repulsive force restores displacement towards each other, and displacement away is restored by gravity. A hydraulic damper is fixed on the top of the cylinder and connected with the upper magnet with a shaft. The set of shocks used with magnets inside them that are used as the fork setup. In this cylinder the arrangement of the magnets is in such a way, place one magnet at the top of the cylinder with any polarity let us consider south polarity on down side. Then place another magnet at the bottom of the cylinder having sou th polarity upside so that they can be parallel each other. Then due to the same polarity of both the magnets the repulsive force generates which gives the movement to the shaft to avoid any unsuitable shocks and the fixed hydraulic damper absorbs the vibrations and instability.The shaft controlled the radial instability, the repelling force and the gravity force. The spring has a property to contract and extend but it cannot be stable, so the shaft is use to stabilize the spring. If the magnets are placed in two orthogonal axes, they repel each other but not in any one direction, so they are also instable. A thrust bearing can use to avoid the instability in which the magnets can be placed, and even if the instability take place the movable magnet will not fly has the advantage in that if instability does occur, the unstable magnet will not fly unpredictably away from the fixed magnet. The vibrations and the instability will be absorbed by the hydraulic damper.It is stated for co mpleteness that the magnet has two poles North South. They will be attract each other if they are facing each other with different polarity, but they will repel each other if they are facing each other with same polarity.That these forces occur is very well known, but the mechanisms that create these forces are beyond the scope of this document. There are several materials of which permanent magnets may be made.2) Working of Linear Motor as a DamperA linear electromagnetic motor works in the straight line instead of work in rotary motion. The movement effect of this motor is very quick. L.E.M. can be used at each wheel in a vehicle which has a conventional shock and spring setup. The L.E.M. can extend as it faces any distraction like pothole and retract as it faces any bump just in milliseconds which is much greater speed than a hydraulic damper. These type of quicker retract and extract movement provides the steering stability by controlling the wheels with respect to the body of the vehicle.The L.E.M. made up of magnets and coils of wires. When current is passed through the coils, the motor retracts and extends so fastly, control unwanted movements. The speed is the major key benefit of the electromagnet. (Bose Elecromagnetic Suspension System, 2010)Fig 3.2 (Bose Elecromagnetic Suspension System, 2010)The L.E.M. is designed in such a way so that it can give the quick respond to absorb the effects of bumps and pothols and also provides a relaxed ride. Moreover, the motor is designed such as it can supply the maximum power in a small package, which allows it to supply sufficient force to avoid the car from rolling and pitching during bad driving.At the time of acceleration, braking and cornering the L.E.M. counterbalance the body motion of a car, which gives the driver a kind of driving idea and passengers comfort ride. For the smooth ride purpose, the wheel dampers are place in each wheel hub to smooth out small road imperfectionst. To generate more power a n amplifier is provided which supplies the a great power to the L.E.M.s. The amplifier is a regenerative design that uses the compression force to send power back through the amplifier. (Bose Elecromagnetic Suspension System, 2010)3.2 Goals of the magnetic designThe design of the magnetic spring has the following requirements1. Freedom instability by one degreeIn exemption instability by on degree generally the stability performance which is forecast by the non linear study is according to the formly build up linearized study. The study of granting immunity instability by on degree shows the relation between magnitude and velocity. As the velocity increases the magnitude increases which is increased by the stable limit cycle amplitude of vibration.Actuators are essential for stability control of every unbalanced axis. Hence the amount of unstable degrees of freedom needs to reduce. In addition to it for well organized passive upended load bearing the direction of the unstable dire ction must be horizontal.2. Ability to support large loadsPermanent magnets must be maintained on the entire free weight of table plus equipment. This weight which is hold up by the electromagnets utilizes considerable amount of power which is unwanted for cost and heat reasons.3. Effective electromagnet actuator placingThe forces which are applied asymmetrically by the actuators who apply a moment on the levitating table which would be unwanted. For rejecting vertical disturbances the electromagnet actuators must be used for the stabilizing of unstable axis.(S. J. Price and N. R. Valerio)Chapter 4TECHNOLOGYThere are three primary types of MAGLEV Technologies wiz that relies on feedback controlled electromagnets (Electromagnetic Suspension or EMS). Ex. TransrapidThe another one relies on the superconducting magnets (Electrodynamic Suspension or EDS) Ex. JR-MaglevAnd the last one and newer , potentially more economical system that uses premagnets i.e. Inductrack4.1 InductrackA newer , perhaps less expensive system is called Inductrack. The technique used in inductrack has a load carrying capacity which is related to the speed of the vehicle, because the permanent magnets induce current in the passive electromagnetic array In the model, the permanent magnets are placed on both sides of the model the function of these magnets is to provide horizontal lift and vertical stability. There is collection of wire loops in the track which is also called as array. There is no power supply in magnets and the model, apart from the speed of the model. The basic concept behind this system is to store the power by developing the inductrack as a motor and flywheel bearing. With only slight design changes, the bearings were unrolled into a linear track. William Post is the father of such a great innovation like inductrack. He had done this experiment at Lawrence Livermore National Laboratory. Inductrack uses Halbach arrays for stabilization. Halbach arrays are the system in whi ch there are some arrangements of permanent magnets which stabilize moving loops of wires without electronic stabilization. Halbach arrays were initially developed for beam guidance of particle accelerators. They also have a magnetic field on the track side only, thus reducing any potential effects on the passengers.4.2 Lift and actuationIn the whole world Japan and Germany are the most active in Maglev research they have produced several difference approaches and designs. The technique used such as the train can be levitated by the repulsive of like poles or the attractive force of opposite poles of magnets. A linear motor propelled the train which is on the track or on the train, or both. In order togenerate the magnetic field which is necessary to propel the train there are massive electrical induction coils are placed along the track.(C.A. Guderjahn S.L. Wipf,2010)4.3 StabilityEarnshaws theorem states that a collection of point charges cannot be maintained in a stable stationar y equilibrium shape solely by the electrostatic interaction of the charges.In the system the static magnetic bearing which uses only electromagnets and premagnets are unstable because of Earnshaws theorem but the diamagnetic and superconducting magnets can support a Maglev steadily. Some conventional Maglev systems the electromagnets having electronic stability are used for stabilization. This works by constantly measuring the bearing distance and adjusting the electromagnets accordingly.4.4 Magnet WeightThe weight of large electromagnet is a major design issue. A very strong magnetic field is required to levitate the massive train, so conventional Maglev research is using superconductor research for an efficient electromagnet.Chapter 5ANALYSIS5.1 kinetics of the magnetic suspension systemThe basic principle of a simple electromagnetic suspension system is shown in Fig.1. the current I which is passes through the electromagnet generates the magnetic force Fm which acts opposite to the gravity and cause a steel ball to levitated position. The force relies on the current I, electromagnet properties and the air gap between the steel ball and the electromagnet.The motion of the steel ball in the magnetic field is verbalised asG Fm = m d2X / dt2..(1)Where,m = the mass of the suspended steel ball,G = mg, the gravity force,X = the air gap between the steel ball and the electromagnet.The magnetic force Fm is a nonlinear function of the current I and the air gap X. The linearization of the static characteristic near the set point (F0 , X0 ,I0) is given asF = F0 + I0 (X X0) + X0 (I I0).(2)The voltage equation of the electromagnetic coil is expressed asU = RI + L dI / dt.(3)Where,U = the voltage,R = the coil resistance, andL = the inductance.Inductance L=f (X, t) is a function of the air gap, the coil, the core, and the steel ball. The magnetic force which is generated by the electromagnet maintained the steady state air gap between the ball and the electromagnet i s manipulated to balance the gravitational force of the ball. The small differences from the operating point are normalized over operating spaces (G, D, Imax , Umax) and they are defined as followsf = , x= , i = , u = (4)Where,f i= the normalized resultant force,x = the normalized air gap,i = the ormalized current, andu = the normalized voltage.X , I , and U = the steady-state values.Substituting Eq. 4 into Eqs. 1, 2, and 3 the dynamics of the systemcan be presented as followsf = -m d2x / dt2 = -m d2x / dt2 = d2x / dt2..(5)f = I0 x + X0 i , (6)u = i + (7)Let the set gains and time constants beKe = X0 , Km = I0 , Te = , Tm = .(8)Therefore Eqs. 5, 6, and 7 can be rewritten asf = T2m d2x / dt2 ..(9)f = Kmx + Kei (10)u = i + Te .. (11)(M. Golob Boris Tovornik, 2010)The block diagram of the linearized model of the electromagnetic suspension system is shown in Fig. 5.2. The linear system draw in the block diagram in Fig. 5.2 is unstable and control science laboratoryle.As per the th eory of vibration, there are two types of analysis,1) The analysis of the Instability and the Vibration without damper and2) The analysis of the Instability and Vibration with damper.These analyses were made in the electronic lab with help of the METLAB Software. For these two setups the two types of simulations were made in METLAB Software. The data used for the analysis is as followsTable 3Nominal System Parameters corporation of the steel ball (m)0.147 kgMaximum air gap (D)0.025 mNumber of coils (n)1200Coil re