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ABSTRACT

In India, motorcycle is one of the most popular common mode of transportation

due to their versatility. Motorcycles are also used for long distance touring, cruising and

sports application. Their engine capacity ranges from 100 cc engines to 1800 cc. The

demand of new and better two wheeler models are increasing which have improved

safety, comfort and performance.

Due to prolonged use of motorcycles, incorrect riding postures, bad road

conditions, and suspension system problems, human body will be strained and results

in back pain, neck pain etc. Out of these factors, the design engineer will concentrate

on suspension system design to reduce the discomfort for the human being.

This project aims to study the feasibility of implementing active suspension

system and preview active suspension system for a two wheeler by way of numerical

modelling, simulation and analysis. First of all, the active suspension system for a 2

DOF system is modelled and analysed. The analysis done are: Frequency response

analysis, and time domain analysis. Time domain analysis are done using two road

inputs. One is a bump input, which is deigned according to the standards, and the other

input is a random road input. Then the two wheeler has been modelled as a 4 DOF

model. The model is assumed to be a linear time invariant system. The controller is

modelled using optimal control theory. Linear quadratic regulator (LQR) controller is

used because the system is assumed to have linear characteristics and the cost function

of the system is quadratic. Wheelbase preview active system is modelled, which utilises

the fact that while travelling in a straight line, rear wheel will have the same input as

that of the front wheel but with a time lag. Thus the problem is modelled as an optimal

preview control problem. This system is also simulated and analysed with same input

as that given to the 2 DOF model. Conclusions are made and tabulated.