Translational Mechanical Suspension: Response of Quarter-Car(1/4) Suspension

Using Simulink Modeling

Presented By:Ishak Mohammad Tanjinul Haque-12108049

Ahashan Ahmed-12108071Sadi Al Mamun-12108078

MD. Mustakim ArIfin-12108083

A Presentation on

Introduction Suspension Types Design requirements Physical setup System parameters Basic Simulink Blocks to do this Design Working Procedure Simulink Model Figure Open-loop response Applications Advantages Disadvantages Conclusion References

Contents

Automotive Suspension is the system of tires, tire air, springs, shock absorbers and linkages that connects a vehicle to its wheels and allows relative motion between the two.

Suspension systems serve a dual purpose —

Contributing to the vehicle's road holding/handling and braking for good active safety and driving pleasure.

Keeping vehicle occupants comfortable and a ride quality reasonably well isolated from road noise, bumps, and vibrations etc. 

Introduction

Suspension Types

A good automotive suspension system should have satisfactory road holding ability.

It should provide comfort when riding over bumps and holes in the road.

When the vehicle is experiencing any road disturbance (i.e. pot holes, cracks, and uneven pavement),the vehicle body should not have large oscillations, and the oscillations should dissipate quickly.

Design Requirements

Designing an automotive suspension system is an interesting and challenging control problem. When the suspension system is designed, a 1/4 model (one of the four wheels) is used to simplify the problem to a 1D multiple spring-damper system. A diagram of this system is shown below.

Physical Setup

(m1) body mass =2500 kg (m2) suspension mass= 320 kg (k1) spring constant of suspension system = 80,000 N/m (k2) spring constant of wheel and tire =500,000 N/m (b1) damping constant of suspension system =350 N.s/m (b2) damping constant of wheel and tire=15,020 N.s/m (u) control force = force from the controller we are going to design.

System Parameters

The following design blocks are needed for our simulink design of suspension.

Basic Simulink Blocks to do this Design

This system is modeled by summing the forces acting on both masses (body and suspension) and integrating the accelerations of each mass twice to given velocities and positions. Newton's law is applied to each mass.

1)

2)Newton's law for each of these masses can be expressed as:3)

4)

Working Procedure

Simulink Model Figure

Open-Loop Response

1. We can easily and efficiently define the response of a ¼ suspension system.

2. For building any costly car, this process is usually

done.Because,this is needed to verify the the response for a translational mechanical system for spring and damper for this Control System analysis.

Applications

1. This design process is efficient. 2. Easily found response.

Disadvantages 1. Very much time consuming process.

Advantages

It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the road or ground forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different.

Suspension system is a very important part of designing a vehicle.We can verify the the response of a suspension system by Control System Analysis using Simulink modeling.

Conclusion

1.www.wikipedia.com 2.www.google.com 3.www.solarnet.com 4.www.mathworks.com

References

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