SEMI –ACTIVE SUSPENSION SYSTEM Presented By – Rohit Agarwal Pulkit Jain 11/13/2018

ABOUT US Rohit Agarwal Alma-Mater: VIT University (2010-2013) ARAI Academy (2013-2014) Academic achievement Merit certificates in all the 3 years of B.tech Participated in BAJA SAE 2013 in which the team stood 4th Projects Completed: Research paper published on Simulation of Drive Train Comprising CVT in IJET Languages Known: English, Hindi, Bengali Extra-Curricular: A grade in A level NCC 11/13/2018

Pulkit Jain Alma-Mater: VIT University (2010-2013) ARAI Academy (2013-2014) Research Experience: Reviewed Research papers on Alternative Fuels Projects Completed: Design and Simulation of Epicyclic Gear Train Numerical Simulation of Spark Ignition Engine Using Wiebe Function Languages Known: English, Hindi, Telugu, German, Extra-Curricular: National Level Table Tennis 11/13/2018

FLOW OF CONTENT INTRODUCTION HISTORY CLASSIFICATION OF SUSPENSION MATHEMATICAL MODELLING EQUATIONS SIMULINK MODEL RESULTS CONCLUSIONS 11/13/2018

INTRODUCTION Suspension includes springs, shock absorbers and linkages Strut Suspension includes springs, shock absorbers and linkages Supports the weight Provides a smooth ride Help in cornering Prevents excessive squat and dive Isolate the passenger compartment from road vibrations Link Tyre Chassis 11/13/2018

VEHICLE LAYOUT 11/13/2018

HISTORY Leaf springs - Obadiah Elliot 1804 1863 Patent for coil spring - R. Tredwell 11/13/2018

HISTORY Contd. Two-Seat vehicle with Dampers - William Brush 1906 Two-Seat vehicle with Dampers - William Brush 1930 Coil spring front suspension (Independent ) - General Motors 1970-80 MacPherson struts. 11/13/2018

CLASSIFICATION Axle Based Spring Based Technology Based Non Independent Independent Spring Based Leaf Spring Coil Spring Technology Based Passive Semi Active MR Suspension 11/13/2018

AXLE BASED 1. Non-independent suspension Both wheel attached to the same solid axle. One wheel upward movement causes a slight tilt of the other wheel. 11/13/2018

Contd. 2. Independent suspension Axles are independent Allows one wheel to move up and down Minimal effect to the other wheel 11/13/2018

SPRING BASED Leaf spring Commonly used in heavy vehicle Acts as a linkage for holding the axle in position Riding comfort is not good 11/13/2018

Contd. 2. Coil spring Most common type in now days cars Provide good ride comfort Absorbs large amount of energy then leaf spring 11/13/2018

TECHNOLOGY BASED Passive suspension Basic type of suspension No external source of energy Components: Linkages Springs Dampers 11/13/2018

Contd. Linkages Springs Movable lever Connects the steering knuckle to the vehicle’s body or frame. Springs Supports the weight of the vehicle Permits the control arm and wheel to move up and down. 11/13/2018

Contd. Dampers Helps in vibration damping Piston moves up and down due to relative motion of chassis and axle Oil flow from one cavity to other through holes 11/13/2018

Contd. Two stroke Compression stroke Extension stroke Friction between oil and piston wall form the damping force Damping force is proportional to velocity 11/13/2018

SEMI ACTIVE SUSPENSION (SAS) Consists of a spring, damper and linkages The value of the damper coefficient Cs can be controlled and updated. This changes the stiffness characteristic of the suspension system Required ride and handling can be obtained 11/13/2018

SAS Contd. Magneto rheological damper A MRD is not very different from a conventional viscous damper The key difference is the magneto rheological (MR) oil and the presence of a solenoid MR oil contains micron-sized ferromagnetic particles in suspension Due to the polarising magnetic field, particles tend to form chains, which modifies the value of the oil yield stress. 11/13/2018

Contd. Rheological properties of oil changes Hence by controlling the solenoid current, continuously variable damping can be produced The energy requirements are extremely low 11/13/2018

PASSIVE V/S SEMI ACTIVE 11/13/2018

MATHEMATICAL MODELLING Quarter car model (passive) Simple way of representing one wheel motion of vehicle Contain : Sprung mass(ms ) Unsprung mass(mu) Tyre represented by spring of stiffness ku road 11/13/2018

Contd. Quarter car model (semi active) The value of Cs is varied by using PID controller 11/13/2018

PID CONTROLLER A proportional-integral-derivative controller Controller calculates an "error" value These values can be interpreted in terms of time: P depends on the present error, I on the accumulation of past errors, and D is a prediction of future errors, based on current rate of change. 11/13/2018

EQUATIONS Spring force ks (xs - xu) Damper force Cs(x’s – x’u) Tyre force ku(xu − y) road 11/13/2018 Ref.-

Vehicle Dynamics:Theory and Application by Reza N. Jazar Contd. Finally we get SPRUNG MASS ms x”s = −ks(xs − xu) − Cs(x’ s – x’u) UNSPRUNG MASS muxu” = ks(xs − xu) + Cs(x’s– x’u) − ku(xu − y) 11/13/2018 Vehicle Dynamics:Theory and Application by Reza N. Jazar

SIMULINK MODEL PASSIVE 11/13/2018

Contd. SEMI ACTIVE 11/13/2018

INPUT PARAMETERS Parameter Symbol Value Sprung mass ms 375 kg Unsprung mass mu 75 kg Spring stiffness ks 3500 N/m Damping coef. Cs 500 N s /m Tyre stiffness ku 193000 N/m Road input step function 11/13/2018 Ref. -

Ref. - boseindia.com/information/ Suspension System 11/13/2018 Ref. - boseindia.com/information/ Suspension System

RESULT Passive suspension(disp.(m)vs time(sec)) Semi active suspension 11/13/2018

FUTURE PROSPECTS Simulink model based on skyhook model Driver comfort To Determine Frequency 11/13/2018

REFERENCES Semi-active Suspension Control By Guglielmino et tal. Vehicle Dynamics : Theory and Application by Reza N. Jazar Semi-active suspension control design for vehicles by sergio et tal. Race Car Vehicle Dynamics 11/13/2018

THANK YOU 11/13/2018