DATE

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DESIGN AND FABRICATION OF CROSS LINK FOUR WHEEL STEERING

PROJECT REVIEW

13/04/2015

P R O J E C T M E M B E R S : R . K O U S I K P R A B H U ( 7 2 0 7 1 2 11 4 0 6 8 ) G . PA L PA N D I A N ( 7 2 0 7 1 2 11 4 1 0 3 ) B . P R E M N AT H ( 7 2 0 7 1 2 11 4 11 1 ) M . R A J A R A M ( 7 2 0 7 1 2 11 4 1 2 2 )  P R O J E C T G U I D E :M r. C . A . J A G A D I SH M . E ,A SS I S TA N T P R O F ESSO R

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STEERING SYSTEM

FUNCTION OF STEERING• Control of front wheel (sometimes

rear wheel) direction.• Transmit road feel (slight steering wheel pull caused by the road surface) to the drivers hand.• Maintain correct amount of effort

needed to turn the wheels.• Absorb most of the shock going to the steering wheel as the tire hits holes and bumps in the road.• Allow for suspension action

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OBJECTIVE

The main objectives for our project

• To reduce turning radius

• To improve handling and stability of vehicle

• To reduce driver work load

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LITERATURE SURVEYS.NO TITLE AUTHOR REMARKS

1. Developing quadra steering system

Manish k.mistry,jagodanadipak

Design and caculation. stability in vehicle

2. Developing four wheel steering system for a car

k.lohith,s.r shankapal,

Theory for steering, To provide neutral steering on vehicle

3. Study of four wheel steering system to reduce turning

Arun singh, abhishek kumar

Parts and equipments required

4. Four wheel steering for future

Dilip.s.choudhari

Quadra steering system

5. Dynamic characteristics of multi function four wheel steering system

I nyoman sutantra,yusuf kaelani

Zero side slip methods

6. Cross link steering system

Ashok B.1, Nitish Singh2, Naman kashyap3

simple kinematic bar mechanism

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ABOUT EXISTING SYSTEM AND ITS DRAWBACKS

A steering system is used to change the direction of motion of the vehicle

and to make the vehicle turn either left or right.

For this purpose, a steering wheel, a steering rod, and a rack and pinion is

connected to the wheels only on the front.

Thus making only the front wheels to steer.

The rear wheels remain constant.

This makes the rear wheels skid when the vehicle turns.

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FOUR WHEEL STEERING

Four-wheel steering (or all wheel steering) is a system employed to improve

steering response.

Increased vehicle stability while manoeuvring at high speed.

It also decreases turning radius at low speed.

By controlling the steering angle of all four wheels, this steering system helps

reduce driver’s steering workload at low speed.

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HISTORY OF 4WS

4WS has its history from the late

1980’s to early 1990’s.

Honda had four-wheel steering as

an option in their 1987-2000

Prelude.

Mazda also offered four-wheel

steering on the 626 and MX6 in

1988.

Honda Prelude

Mazda MX6

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CROSS LINK MECHANISM

The material selected for cross bar and side bar is duplex 2205 stainless steel hollow pipes of 25.4mm diameter and 2mm thickness due to its high tensile strength and its fracture toughness.

The setup requires the use of three ball joints along with a steering rack and pinion assembly and a modified knuckle for the attachment of shaft in the rear end diagonally.

The material selected for the bar is a type of super stainless steel having following properties [2]:

Ultimate strength = 620 MPa Yield Strength = 570 MPa Density = 7805 Kg/m3

NOMAL MODE

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WORKING

The setup consists of one cross bar which runs between front and rear ends cross ways.

The bar is joined to the frontier side of the front knuckle through ball joint from one end and connected to the rear side of the rear knuckle with another ball joint.

Another kind of bar, side bar (similar to a toe link) connects the rear two knuckles.

All four wheels are linked to each other, making it a constrained system.

WORKING MODE

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WORKING

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AT LOW SPEEDrear wheels are turnedin opposite direction

of front wheels

(below 40 miles or 64 kilometers per

hour), in the negative phase, the rear

wheels turn in the opposite direction of the

front wheels ,Reduces turn radius up to 20

percent , Improves maneuverability ,Eases

parking , Simplifies trailer positioning

At moderate speeds (around 40 miles or

64 kilometers per hour), the rear wheels

remain straight, or neutral

WORKING MODE

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CALCULATION

• Gross Weight (m) = 1350 kg. • Weight of vehicle (W) = m * g = 13243.5 N• Radius of Wheel (r W) =0.3556 m.• Radius of curvature(R) = 1.7868 m. • Width of Track(x) = 1.295 m. • Wheel Base (b) =1.295 m.• Distance of C.G. vertically above the road surface (h) = 0.55 m.• Distance of C.G. horizontally from rear wheel axle (l) = 0.963 m. • Linear velocity (V) = 16 m/s.• Normal Steer Mode: Radius of curvature(R) = 3 m. • Cross Steer Mode: Radius of curvature(R)=1.7868 m. • %Reduction= (3-1.7868/3) * 100 = 40.44 % .

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ADVANTAGES OF 4WS

Vehicles move smoothly both in the city and on winding roads.

Added stability means vehicles can be driven safely.

Quick and responsive control system will allow gentle steering

operation.

At high speeds, the four wheel steering system avoids skidding in cars.

At slow speeds, the four wheel steering system helps in reducing

turning radius by 21% which has its applications in parking.

The mechanism can be controlled electronically or hydraulically.

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DISADVANTAGES OF 4WS

Complex links to connect front and rear wheels.

Expensive.

Additional weight to the vehicle.

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RECENT APPLICATIONS

4ws used in large farm vehicles and trucks.

Monster truck.Our setup can be applied on the

vehicles which have high ground clearance ( Lorry, buses All- terrain vehicles, Sports utility vehicles) and large turning radius.

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2WS 4WS

Only front wheels are steered.

Turning radius is large.

Steering response and stability are

less.

Less complicated.

More complicate for lane change.

Both front and rear wheels are steered.

Turning radius is smaller than 2WS.

Steering response and stability are high.

More complicated. Easily taking lane change

COMPARISON

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COMPARISION

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REFERENCE

[1] PACEJKA, H. B. 2006. Tyre Mechanics and Vehicle Dynamics, Butterworth-Heinemann .

[2] Bansal, R.K. 2010. A textbook of Strength of Materials, Laxmi Publications.

[3] REIMPELL, J. 2001. The Automotive Chassis - Engineering Principles, Butterworth-Heinemann .

[4] William F. Milliken, Douglas L. Milliken, 1995. Race Car Vehicle Dynamics , Society of Automotive Engineers

[5] Swanson Analysis Systems, Inc. ANSYS software (Version 14.0). [6] Dassault Systèmes SolidWorks Corp., a subsidiary of Dassault

Systèmes, S. A. (Vélizy, France) Solidworks software (December9,2009), version 4.

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THANK YOU