innovative question paper

7/30/2019 innovative question paper

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Mukti Nath Gogoi

PhD Progress seminaron

Vehicle Differential

Supervisor: Dr. Santanu Sarma

Associate professor

Department of Electronics and Communication

Engineering

School of Engineering, Tezpur University, Napaam,

Sonitpur, Assam-784 028


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Outline

Vehicle differential

a) introduction

a) Its role in the Vehicle

Mechanical differential

a) Working principle of the mechanicaldifferential

b) Disadvantages of the mechanical differential

Electronic differential

a) introductionb) Advantages over mechanical differential

Literature survey

Conclusion

References


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Vehicle differential, Introduction

Differential is a small device that helps in splitting

the Energy/torque of the cars engine in such away, which will allow the driving wheels to move at

different speed.


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Vehicle differential, Its importance

Differential in a vehicle has mainly four jobs to

do:

To give the required engine power (torque)at the

wheels.

To act as the final gear reduction in the vehicle,

showing the rotational speed of the transmission

one final time before it hits the wheel.

Splits amount of torque going to each wheel.

To transmit the power to wheels while allowing themto rotate at different speeds.


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Vehicle differential, Its role

differentials play an important role while turning a

car. The inside and outside wheels of a car turn in

different radius corners.

The outside wheel has to turn faster

than the inside one in order to

cover the greater distance in the

same amount of time.

If differential is not included than

In this case a certain amount of

tension would build up And this tension would relive

itself with a wheel skipping over the surface.

W0 > Wi and R0ut > Rin


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Mechanical differential, Parts

Pinion Drive Gear: transfers power from

the driveshaft to the ring gear.

Ring Gear: transfers power to the

Differential case assembly.

Side/spider gears: help both wheels

to turn independently when turning.

Differential case assembly: holds the

Ring gear and other components that drive the

rear axle.

Rear drive axles: steel shafts that transfer torque from the differential assembl

drive wheels.

Axle housing: metal body that encloses and supports parts of the rear axle as


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Mechanical differential, The Working

principle

>>Drive shaft spins the Pinion gear.

>>Pinion gear turns the larger ring

gear to produce gear reduction.

>>When the car drives straight ahead

no differential action occurs, both

axles turn at the same speed and

the spider gears do not rotate.

>>Differential case spins the sun gears

which are attached to the axles.

>>When the car turns,the differential must compensate for the

difference in distance traveled by the drive wheels. This roll around

the side gears, allowing the inside wheel to turn more slowly and the

outside wheel to turn faster.


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Disadvantages of the mechanical

differential

When one of the tires hits ice or a slippery surface, itbegins to spin and the majority of torque is directed to

the spinning wheel, leaving very little for the wheel

with the good traction.

To solve this problem limited slip differential (LSD) is

invented, where a series of coupled clutches which

limit the difference in the rotation of the inner and

outer wheels to a specific limit.

The disadvantage of LSD is that it may require an

additive to be added to the gear oil. Without it the


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Electronic differential, Introduction

The electronic differential is a new form of

differential, which provides the required torque for

each driving wheel separately and allows different

wheel speeds.

It reduces the mechanical transmission componentsis related to the elimination of the mechanical

differential gear introducing an electronic substitute

system, called electronic differential.

Figure: mechanical differential

system

Figure: Electronic differential system


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Electronic differential, Advantages

over mechanical differential

Much simpler. It can eliminates the need ofgearbox and clutch.

It uses several electric motors, one for each driving

wheel allowing independent control of each wheel

It is reprogrammable in order to include new

features or tuned according to the drivers

preferences.

Allows distributed regenerative braking. Faster response times.

Accurate knowledge of traction torque per wheel.


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Literature survey

The research on electronic differential propulsion

system is quit new and probably japan is the first

country to implement it in 2006.

Researchers named S. M. Wasfy, M.M.Eissa,

G.M.A.Sowilam

, M.Abdel monem tries to modeland analysis of a proper traction system based on

EDS for two wheel independent drive EVs [1]. When car is in a straight trajectory:- the two rear wheels run

exactly at the same speed (for a steering angle equals zero)

When the vehicle turns right and left:-

Firstly based on the steering angle a reference speed for the

both rear wheel are selected according to the trajectory.

Then With the information about the real speed of the

vehicle, on left and right sides, they are making a control

algorithm.


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Literature survey, continued

>>WLEFT, WRIGHT :- Two rear wheels angular velocity as a

feedback signal>> WL(REF), WR(REF) :- Reference for the angular velocity based on

steering angle

Figure: proposed system[1]


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Three researcher Kada Hartani, Yahia Miloud, and

Mohamed Bourahla form Algeria tries to propose asystem to improve the vehicle stability based on the

method of electronic differential using sliding mode

control[2].

SMC, is a nonlinear control method .

They analysed the nonlinear behaviour of the differential

system in relation to the speed and steering angle, as well asvehicle structure.

The proposed propulsion system consists of two permanent

magnet synchronous machines that ensure the drive of the two

back driving wheels.


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Yong Zhou, Shengjin Li, Xunqi Zhou, Zongde Fang

three Chinese researcher tried to implement acontrol strategy of Electronic Differential with Four In-

wheel Motors of EV [3]. Orders such as starting, accelerating

or decelerating, turning, braking etcare given via a steering wheel or pedal .

All of the orders are converted into

analog signal via several linear

displacement sensors, and then the

analog signal will be transferred

to a controller.

After analyzed the signal, controller

regulates the speed of four motors

makes them have different speed.


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Some researchers from Portugal proposed a FPGAbased implementation of Electronic differentialcontrol system [4]. In this paper they are developinga fully integrated on chip electronic differentialcontroller employing FPGA technology.

Electronic differential can also be implementedadaptively. A paper written by the BekheiraTabbache, Abdelaziz Kheloui, and Mohamed El

Hachemi Benbouzid concerns about the vehiclestability based on the adaptive electronicdifferential[5].

They used a DSP processor chip as a controller. they have proposed the traction drive uses direct torque control


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Li Zhai, Shouquan Dong from Beijing has proposed

A comprehensive control strategy of speed andtorque based on Neural Networks PID electronicdifferential to calculate object speed of fourwheels[6].

Used four PID controller.

When the voltage on the bus goes

beyond the limitation, the energy

absorber begins to work and

absorb the redundant energy.

electronic differential speed controller

would calculate four wheels velocity

v and steering angle .

A comprehensive PID controller is

used to perform speed-torque

coordinate control of ED.


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Some researcher of Applied Electronics Group,

Faculty of Engineering, National University of Rio

Cuarto, had studied the principles and methods

actually developed in electronic differential system

around the world and then they implemented most

appropriate control strategy for this using Field

Oriented Control (FOC) or vectorcontrol method of

AC motors[11].

stator current, rotor flux position and rotor speed are measured.

A DSP processor TMS320F2812 is used for processing ad

controlling purposes.


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Conclusion

During these literature surveys it has noticed that almost

all researcher concentrates on the vehicle stabilityissues with the help of electronic differential and aredesigned to keep some stability-related quantity[] (as fore.g. wheel slip) in a saferegion.

Some situations may happen in which we have to copewith extreme steering conditions as for example in aaccidental case and acceleration demand in car racingscenario. In these cases we require a controller which is

able to cope with these conditions. Till now It is foundthat no researcher is given importance in it. So this isone of a point which we can approach in near future.

Development of a cost effective and a simpleimplementation will have considered to be a another


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References

[1] S. M. Wasfy, M.M.Eissa(SMIEEE), G.M.A.Sowilam,

M.Abdel monem.:MODELING AND ANALYSIS OF A

TRCTION CONTROL SYSTEM FOR TWO

INDEPENDENT WHEEL DRIVES-ELECTRIC VEHICLE,

International Conference on Renewable Energies and

Power Quality (ICREPQ10) Granada (Spain), 23rd to25th March, 2010.

[2]Kada Hartani, Yahia Miloud, and Mohamed Bourahla,:

Vehicle Stability Improvement Based on Electronic

Differential Using Sliding Mode Control. 7th WSEASInternational Conference on Electric Power Systems,

High Voltages, Electric Machines, Venice, Italy,

November 21-23, 2007. PP:331-338.

[3]Yong Zhou1, Shengjin Li2, Xunqi Zhou2, ZongdeFan 2.:The Control Strate of Electronic Differential


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References, Continued

[4]Ricardo Pinto de Castro, Hugo Santos Oliveira, Jos

Ricardo Soares, Nuno Miguel.;A new FPGA based

control system for electrical propulsion with electronicdifferential.

[5]Bekheira Tabbache, Abdelaziz Kheloui, and Mohamed ElHachemi Benbouzid, Senior Member, IEEE.: An

Adaptive Electric Differential for Electric Vehicles MotionStabilization.IEEE transactions on vehicular technology,vol. 60, no. 1, january 2011

[6]Li Zhai, Shouquan Dong.: Electronic Differential Speed

Steering Control for Four In-wheel Motors IndependentDrive Vehicle.Proceedings of the 8th World Congress onIntelligent Control and Automation June 21-25 2011,Taipei, Taiwan.

[7]Y. Hori, senior member IEEE, Future vehicles driver by

electricity and control research on four wheel motored


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References, Continued

[8]Y. E. Zhao, J. W. Zhang and X. Q. Guan,: Modeling and

Simulation of Electronic Differential System for anElectric Vehicle with Two Motor-Wheel Drive. IEEE

Transactions on Vehicular Technology 2009.

[9]Manu Jain, Student Member, IEEE, and Sheldon S.

Williamson, Member, IEEE,:Suitability Analysis of In-Wheel Motor Direct Drives for Electric and Hybrid Electric

Vehicles. IEEE Electrical Power & Energy Conference

2009.

[10]K. Vitols, I. Galkin,: Analysis of Electronic Differentialfor Electric Kart. 15th International Power Electronics

and Motion Control Conference, EPE-PEMC 2012 ECCE

Europe, Novi Sad, Serbia.

[11]Guillermo A. Magallan, Cristian H. De Angelo,Guillermo Bisheimerand Guillermo Garcia : A


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