Project

MODELLING OF A CONTINUOUSLY VARIABLE TRANSMISSION (CVT) BAJA ALL TERRAIN VEHICLE(ATV) MODEL in Closed Loop & Open Loop.

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CONTINUOUSLY VARIABLE TRANSMISSION (CVT)

Parts:

Two canonical pulleys and a steel belt make up a basic CVT.

Input pulley or Drive pulley:

Connected to input shaft for input power. This turns the Steel belt.

Output pulley or Driven pulley:

Steel belt turns this. Connected to output shaft and rear wheels.

Under Drive:

During this output pulley speed is less than input pulley speed. Attained by primary pulley radius less than secondary pulley radius.

Over Drive:

During this output pulley speed is greater than input pulley speed. Attained by primary pulley radius greater than secondary pulley radius.

VEHICLE MODELLING:

Given CVT ATV simscape model has below

Engine

CVT

Vehicle body

Gear raio block used to take the speed difference between output shaft and the vehicle body. For this model it is calculated as 10.

Engine:

Data input given to the Engine block are derived from data points we got from the Torque - Speed plot of this vehicle.

CVT:

CVT ratio is fed to CVT block .In CVT the states of pulleys are modelled here using two Ideal mechanical rotational inertia blocks. and gear ratio block

Gear ratio is fed to gear ratio block.

VEHICLE BODY:

This simscape model desiged of Vehicle body and four simple tire blocks.

Once the throttle input is given, vehicle attains the max speed after some trasition time.

Vehicle scope readings in over drive

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CVT ATV MODEL In Closed Loop:

Closed Loop system for this model is achieved by feeding the data to look up table in the CVT. Look up table data input is done via a matlab script.

Velocity output for Throttle input 1.