In-Wheel Suspension with Automatic Camber Control for Improved Handling : Design, Prototype Development and Modal Analysis

1. In-Wheel Suspension with Automatic Camber Control for
Improved Handling :
Design, Prototype Development and Modal Analysis
Dilip Kumar (1MV13ME024)
Nishant Tiwari (1MV13ME063)
Sameer Rafiq Shah (1MV13ME123)
Eshan Dhar
Research Scholar, ICER
Indian Institute of Science, Bangalore
CTO Gyrodrive Machineries Pvt Ltd

2. Literature Survey
1. Suspension geometry was studied from Vehicle Dynamics: Theory
and Application by Dr. Reza N. Jazar
2. Double Wishbone Geometry was studied from BMW X5 Model
Specification.
3. Content regarding the suspension was taken from Wikipedia.
4. Previous Research Papers were referred from SAE Publication
“Optimization of Double Wishbone Suspension System with
Variable Camber Angle by Hydraulic Mechanism”
5. Design of Parts was from done Design of Machine Elements by
V.B Bhandari and Lingaiah Machine Data Handbook.
6. Modal Analysis was studied from Modal Testing : Theory and
Practice D. J Ewins.
7. Noise and Vibration Analysis Signal Analysis and Experimental
Procedures by Anders Brandt was referred to carry out Impulse
Hammer Test.
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3. Introduction to Suspension Systems
What is a Suspension?
Suspension is the system of tires, tyre
air, springs, shock absorbers and
linkages that connects a vehicle to its
wheels and allows relative motion
between the two.
The job of a car suspension is to
maximize the friction between the tires
and the road surface, to provide
steering stability with good handling
and to ensure the comfort of the
passengers.
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4. Types of Suspension Systems
Dependent Suspension
• Satchell link
• Panhard rod
• Watt's linkage
• Mumford linkage
Independent Suspension
• MacPherson strut/Chapman
strut
• Upper and lower A-arm
(double wishbone)
• Multi-link suspension
• Leaf springs
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5. Types of Suspensions used in Vehicles
Leaf Springs Suspension MacPherson Strut Suspension
Double Wishbone Suspension Multilink Suspension
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6. Problems with Current Suspension
Systems
Leaf Spring Suspension • They are much stiffer than helical springs.
• Less Ride comfort due to no damping action.
• Restricts the swing of wheel in vertical direction.
• Less Adjustments.
MacPherson Strut
Suspension
• Raises the CG of the car as the strut is almost vertical.
• Causes change in camber while cornering.
• Poor handling.
Double Wishbone
Suspension
• Occupies More Space.
• Design Process is Complicated.
• Lack of Camber when wheel moves into bump
Multi Link Suspension • Too Complicated.
• Requires High Maintenance.
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7. Vehicle Axis System
• Sprung Mass and Un-sprung Mass
• Cartesian Coordinate System
• X= Longitudinal, Y= Lateral & Z= Vertical
• Rotations about axes
X= Roll
Y= Pitch
Z= Yaw
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8. Tyre Terminology
Camber Angle
• Angle between the wheel plane and the vertical
• Taken to be positive when the wheel leans
outwards from the vehicle
Castor Angle
• Inclination of the swivel pin axis projected into the
fore–aft plane through the wheel centre
• Positive in the direction shown.
• Provides a self-aligning torque for non-driven
wheels
Toe-In and Toe-Out
• Difference between the front and rear distances
separating the centre plane of a pair of wheels.
• Quoted at static ride height – toe-in is when the
wheel centre planes converge towards the front of
the vehicle
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9. Proposed Concept of In-Wheel Suspension
System with Automatic Camber Control
We have proposed the concept of an In-Wheel
Suspension system.
It will
• Occupy less space.
• Withstand and damp shocks.
• Prevent Uneven Tyre Wear.
• Improve Traction while cornering.
• Provides maximum contact between the wheels and
road.
• It will provide more space in luggage area.
• Sustain 6132 N of Load.
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11. Ill-effects of Fixed Camber Angle
• Fixed camber angle results in a fixed contact between the
road and tyre thereby decreases traction.
• Lack of Road-Tyre contact while cornering leads to lesser
stability.
• Decreases efficiency and Increases Fuel Consumption.
• Increases Uneven Tyre Wear.
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12. Solution for controlling Camber angle
• Automatic camber control always maintains maximum contact
between Road and tyre.
• It helps to maintain traction while cornering.
• It also prevents uneven tyre wear.
• Automatic Camber Control will be done through a jack
coupled with a servomotor. This will be demonstrated in the
prototype through Arduino UNO R3 microcontroller and a
servomotor.
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13. Features of In-Wheel Suspension
• This suspension is designed for Light Weight
Electric cars (Weight up to 1500 Kgs).
• This suspension is for Rear Wheels.
• It occupies less space and is compact.
• It provides more space in rear luggage
compartment.
• It provides Automatic Camber Control and
improves traction and mileage.
• Prevents uneven tyre wear.
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14. Methodology
Stage 1 (DESIGN & SIMULATION)
• Design and CAD Modelling.
• ANSYS Simulation (Structural Simulation).
• Result Interpretation and Design Iterations.
Stage 2 (Manufacturing)
• CNC Machining of Parts.
• Purchase of Standard parts.
Stage 3 (ASSEMBLY)
• Brazing of Parts
• Assembly of Prototype.
Stage 4 (MODAL ANALYSIS)
• Impulse Hammer technique to study the response of the system
and hence determine the Eigen Values and frequency.
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15. CAD Model of Parts
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16. Stage 1: Design of Parts
• Parts were designed as per the initial design of
the In-Wheel suspension.
• Iterations were performed and the dimensions
and geometry was changed and fillets were given
to reduce stress concentration.
• Changes were made such that parts should
satisfy FFF (Form, Fit, Function)
• Parts were designed keeping in mind the space
constraint since all the parts should
accommodate inside the rim of the wheel and
function as per requirement.
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17. Sample Design for Bracket
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18. Other Parts of the In-Wheel Suspension
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19. Stage 2: Simulation
Based on the forces inferred from the free body diagram, the input forces and
boundary conditions such as fixed regions were simulated in ANSYS 17.1 and
Structural Analysis was carried out.
Assumptions
• Total weight of the car = 1500 kg
• Unsprung mass = 15% of total weight = 225 ~ 250 kg (including all the
parts )
• Sprung mass = total weight – unsprung mass = 1500 – 250 = 1250 kg
• Unsprung mass on each wheel = 62.5 Kg ; force = 613.125 N
• Weight acting on each suspension = (sprung mass /4) = 1250/4 = 312.5 kg
~ 315 kg = 3065.6 = 3066 N
• Considering FOS = 2
• Weight acting on each suspension = 6132 N
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EN 19 Material Specifications

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Simulation Results

25. Stage 3: Manufacturing
Manufacturing carried out at Fortune Industries, Peenya
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26. Parts Manufactured
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27. Assembly
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28. Automatic Camber Control
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γg = γb + φ

29. Automatic Camber Control Prototype Demonstration
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30. Programming the Microcontroller
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31. Stage 4: MODAL ANALYSIS
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33. Using MATLAB to solve the above matrix
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35. Impulse Hammer Technique
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Data Acquisition from LabVIEWTM

37. Numerical Analysis and MATLAB Solution
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38. Results
• The Impulse hammer technique was used to determine the
response of the system. The impulse signal was given and the
damped frequency was recorded.
• Eigen values were calculated to find the corresponding
frequencies and the experimental result was verified with the
MATLAB calculations.
• The system was able to damp the sudden vibrations hence the
suspension so designed is structurally stable and responsive.
The suspension was able to sustain the load and damp the
sudden vibration which is the main function of the
suspension.
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39. FUTURE SCOPE OF WORK
• The Suspension can be further improved by using Forged
Composite® Wishbones which is currently being used by Automobili
Lamborghini. This forged composite material is 30% lighter than
steel and hence makes the suspension even lighter.
• The spokes of the rim can be designed in the shape of a bladed
turbine which is currently being used by Koenigsegg in Agera R
models. When the rim rotates, this type of spoke design acts like a
fan or a turbine which provides passive cooling to the suspension
elements.
• Magnetorheological dampers can be used in place of air or oil
based damper which allows the damping characteristics of the
shock absorber to be continuously controlled by varying the
power of the electromagnet according to the road conditions and
different driving modes.
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40. Thank You
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