Electromagnetic suspension system

Ideal Suspension System

F/O Engineering and Technology Jamia Millia Islamia1Mahindra Igniters Independent SuspensionGreater ride comfort,SaferStable on/off roadBetter tractionBeam Axle SuspensionSimple in ConstructionInexpensiveGreater loading capacityLow self weightF/O Engineering and Technology Jamia Millia Islamia2Electromagnetic Suspension SystemPrepared by Bilal Hasan Syed6th SemesterB.Tech Mechanical Engg.Jamia Millia Islamia

Mahindra Igniters SolutionClassification of suspension systemsF/O Engineering and Technology Jamia Millia Islamia44Mahindra IgnitersHydraulic Suspension SystemExamples of vehicles employing this technology BMW has recently developed an antiroll control (BMW-ARC) system by placing a hydraulic rotary actuator in the center of the antiroll bar at the rear of the vehicle as shown on figure in next slide.Mercedes has developed an Active Body Control System, which uses high-pressure hydraulics to pre-stress the spring, hence generating antiroll forces without coupling the left and right wheels (as in the case of an antiroll bar).

F/O Engineering and Technology Jamia Millia Islamia5Hydraulic Suspension SystemF/O Engineering and Technology Jamia Millia Islamia6

Fig no. 1 ARC system of BMW using a hydraulic rotary actuatorHydraulic/Pneumatic Suspension SystemAdvantages areVery high force densityEase of controlEase of DesignCommercial availability of various partsReliabilityCommercial Maturity

F/O Engineering and Technology Jamia Millia Islamia7Mahindra Igniters7Hydraulic/Pneumatic Suspension SystemDisadvantages areconsidered inefficient due to the required continuously pressurized system;relatively high system time constant (pressure loss and flexible hoses);environmental pollution due to hose leaks and ruptures, where hydraulic fluids are toxic;mass and intractable space requirements of the total system, including supply system, even though it mainly contributes to the sprung mass.F/O Engineering and Technology Jamia Millia Islamia8Sprung mass mass of chassis and body wrt to mass of wheels and axle.. Should be low

Mahindra Igniters8Electro-magnetic Suspension SystemBasic IdeaMagnetic repulsion can be used to absorb shocks. And since response to input signals is very fast in electro-magnetic induction motors, its use can give beneficial results. Linear motion can be achieved by an electric rotary motor with a ball screw or other transducers to transform rotary motion to linear translation. However, the mechanism required to make this conversion introduces significant complications to the system. These complications include backlash and increased mass of the moving part due to connecting transducers or gears that convert rotary motion to linear motion (enabling active suspension). F/O Engineering and Technology Jamia Millia Islamia9The Motor Principle: when a current-carrying conductor is located in an external magnetic field perpendicular to the conductor, the conductor experiences a force perpendicular to itself and to the external magnetic field.Mahindra Igniters9Electro-magnetic Suspension SystemF/O Engineering and Technology Jamia Millia Islamia10Overcomes the disadvantages of hydro/pneumatic suspension as follows-No need for continuous power,Ease of control,Absence of fluidsRelatively high Bandwidth (tens of hertz)

Mahindra Igniters10Bose Suspension System It consists of Linear electro magnetic motors attached on each wheel,Power amplifiers at each wheel,A set of control algorithms.WorkingThis linear electromagnetic motor responds quickly enough to counter the effects of bumps and potholes while maintaining a comfortable ride.Electrical power is delivered to the motor by a power amplifier in response to signals from the control algorithms.The bidirectional power amplifier allows power to flow into the linear electromagnetic motor and allows power to be returned from the motor.

F/O Engineering and Technology Jamia Millia Islamia11 - An application of EM suspensionMahindra Igniters11Bose Suspension SystemThis suspension system requires less than a third of the power of a typical vehicles air-conditioning system, i.e., hundreds of watts. Compared with hydraulic actuators, the main advantages of electromagnetic actuators are as follows:Increased efficiency,Improved dynamic behavior,Stability improvement,Accurate force control,Dual operation of the actuator.F/O Engineering and Technology Jamia Millia Islamia12Fast response of EM coil compared to Hydraulic/pneumats. Actuate dampers within fraction of seconds. Mahindra Igniters12Bose Suspension SystemF/O Engineering and Technology Jamia Millia Islamia13

Fig no. 2- Bose Suspension SystemDriving through curves

F/O Engineering and Technology Jamia Millia Islamia14Mahindra Igniters14Driving through long Bumps

F/O Engineering and Technology Jamia Millia Islamia15Bose Suspension SystemThe disadvantages are as follows:Increased volume of the suspension, since the force density of the active part of hydraulics is higher than for electromagnetic actuation, i.e., system mass and volume could be less;Relatively high current for a 12- to 14-V system;Conventional designs that need excitation to provide a continuous force;Higher system costs.F/O Engineering and Technology Jamia Millia Islamia16We need to reduce the High cost of the Bose suspension system, so that it can be put into use by normal cost vehicles. What if we can combine the use of active and passive suspension system? This idea can yield to a modified suspension system.Mahindra Igniters16 Proposed DesignF/O Engineering and Technology Jamia Millia Islamia17Basic IdeaTo combine the use of both Active and Passive suspension. The general Macpherson system can be used and the passive shock absorber can be replaced by electromagnetic dampers.

Basic ComponentsElectromagnetic DamperPassive Coil SpringPower supplierControl Unit

To be able to use in a Macpherson type of system, the shape of the magnets have to be changed. The LEM of Bose system doesnt use the coil spring. It simply carves out the shape of the pothole and bump, i.e. the tire extends or withdraws according to the road surfaceMahindra Igniters17Proposed DesignGeneral ModificationFor an electromagnetic coil to be used in a Macpherson type of suspension system, its shape has to be modified. F/O Engineering and Technology Jamia Millia Islamia18

FFig no. 3 Linear Electromagnetic coil of Bose SystemProposed DesignGeneral ModificationIt has to be made into a cylindrical shape or moreover a tubular shape so that it can be adjusted in Macpherson system.

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FFig no. 4 coil shape of the proposed designProposed DesignF/O Engineering and Technology Jamia Millia Islamia20

Coil springPassive damperPermanent MagnetsBump stopEncoder Shaft3 phase CoilCoil springsPermanentmagnets(A)(B)(C)Fig no. 5 Suspension struts. (a) Passive. (b) Active interior-magnet TPMA, (c) Active exterior-magnet TPMA.So the entire sytem would look like this.Mahindra Igniters20Proposed DesignWorkingWhen the vehicle moves on the road the irregularities are sensed by the control unit sensors. Power is supplied by the to EM dampers. Signals are sent to Electromagnetic dampers which extend/withdraw according to need. Wheels would then trace the path of irregularity. Entire process would take fractions of second to initiate. The extra shocks would be absorbed by the passive coil spring. Power RegenerationThe bidirectional power supplies allows power to flow into the tubular electromagnetic motor and allows power to be returned from the motor. For example, when the suspension encounters a pothole, power is used to extend the motor and isolate the vehicles occupants from the disturbance. On the far side of the pothole, the motor operates as a generator and returns the power back through the supplies.

F/O Engineering and Technology Jamia Millia Islamia21Mahindra Igniters21Proposed DesignSafetyIn general, the contact with the road surface is increased. When a car turns through corner or curves, the effect of body roll is almost eliminated. This would decrease the chance to topple over the sides making it safer for the passenger. Also the smoother movement of the vehicle, would prevent damage of the mechanical parts. Thus, making safer for the parts of vehicle.Ride-ComfortThe fast response of this system, is able to cancel out the vibration up to a very large extent making it very comfortable. Fail SafeEven if the power supply fails, the passive spring would still absorb the shocks and the regenerative power would help run the EM damper. F/O Engineering and Technology Jamia Millia Islamia22Body roll- term used to describe the tilting of cars on other side of the turn taken.Mahindra Igniters22Proposed DesignLimitationA lot of research still has to be done to bring this design into usable technologyIn general, the entire system installation cost is expected to be quiet high. Cost Cut-outsComparing to Bose system only a shock absorber has to be changed, hence cost compared to Bose sys should be less.Operating cost is less, since comparatively a low power is required to operate.Comparing to active hydraulic system, its cost would be very less. (no use of compressors, lesser power consumption) On observing level of comfort, safety and loading; compensation could be made.F/O Engineering and Technology Jamia Millia Islamia23ConclusionActive suspension offers many benefits over conventional and semi-active suspension systems Electromagnetic suspension is a high bandwidth and efficient solution for improving handling and comfort Proposed design of tubular permanent magnet coil in dampers offers a high force density and fail-safe solution.

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