Project

AIM :- To carry out a system level simulation of an All-Terrain vehicle and to prepare a technical report explaining the model

properties and comments on the results.

Theory :- An All-terrain vehicle(ATV), also known as light utility vehicle(LUV),a quad bike or simply a quad as defined by the ANSI(American National Standards Institute), is a vehicle that travels on low-pressure tyres, with a seat that is straddled by the operator along with the handle bars for steering control. As the name implies it is designed to handle a wider variety of terrain than most other vehicles.ATVs are intended for use by a single operator,although some companies have developed ATVs intended for use by the operator and one passenger.The rider sits on and operates these vehicles like a motorcycle, but the extra wheels give more stability at slower speeds.ATVs are used in all types of applications such as farming and industrial use.

History:-

• ATVs were developed in Japan so that isolated farmers could transport their crops and supplies across rugged terrain. In 1969 the Honda introduced the All terrain cycle(ATC) in United states. The ATC had a three fat wheels and was promoted as a recreational vehicle.
• After 1988,ATVs fell somewhat out of favour as a recreational vehicle because of consumer products safety commission report.ATV riders were involved in a disproportionately high number of accidents due to riders immaturity,inexperience,lack of safety training.
• Recently a new generation of recreational riders, with a growing awareness of safety have rediscovered the fun of ATVs.
• While newer ATVs have better safety features than their predecessors,they also have faster,better performance engines that make safety an even more critical issue to be addressed by all responsible riders.

Uses :- They are used in a variety of industries.

• Border patrol
• construction
• Emergency medical services
• Land management
• Law enforccement
• Militiary mineral exploration
• Oil exploration
• Pipeline transport
• Search and rescue operations
• Small-scale forestry
• Surveying etc.

Study1 :-

Case1:- Simulink model for Baja ATV with CVT :-

Major components in the model :-

Continuously variable transmission drive (CVT) :- It is better to have more gears in a transmission, since it can optimize engine speed in a variety of driving conditions. That means low gears can provide better acceleration while higher gears can maximize fuel economy.CVT's differ from traditional automatic transmissions in that they don't have gears that provide "steps" between low and high operations.Instead the majority of them work via a pair of variable-diameter,cone shaped pulleys connected by a steel or composite belt.The halves of each pulley are alligned with the pointed ends of cones touching.These form a V-shaped groove in which the connecting belt rides.One side of the pulley is fixed and the other side is movable,actuated by the hydraulic cylinder.The cylinder can increase or decrease the amount of space between the two sides of the pulley.This allows the belt to ride lower or higher along the walls of the pulley,depending on the driving conditions,thereby changing the 'gear ratio'.

CVT Block :-

Variable Transmission Ratio :- It represents a variable ratio gearbox such as implemented by mechanical belt CVT,electric or hydraulic transmissions.The physical signal input defines the ratio of input to output angular shaft velocities.Connections B(base) and F(follower) are mechanical conserving ports.

Engine:- Engine represents a system level model of spark-ignition and diesel engines are suitable for initial stages of modelling when only the basic parameters are available.Optional idle speed and redline controllers are inluded.The throttle input signal T lies between zero and one and specifies the torque demanded from the engine as a fraction of the maximum possible torque.Connections F and B are mechanical rotational conserving ports associated with the engine crankshaft and engine block respectively.Connections P and FC are physical signal output ports through which engine power and fuel consumption rate are reported.

Input Signal :- A signal builder is used to create signals for brake and throttle.

CVT Gear Ratio Input:-

Torque vs Engine Speed Input:-

Vehicle Body:-

Output for Case1:-

Vehicle speed :-

It is clear from the graph that vehicle attains its maximum speed at V=55km/hr and then it remains constant.

CVT shaft RPM :-

These graphs show the variation in angular velocities of input and output shafts of the variable gear transmission system.These values differ with respect to the gear ratio.

Case2 :- Simulink model for Baja ATV with CVT using dashboard

In this model we have a dashboard which contains knobs to control the inputs.In this case,the inputs 'Throttle' and 'brake' are not provided using signal builder.A knob is provided to control both the parameters in real time for the user.

Output for Case2 :-

Vehicle speed:-

It can be observed from the graph that the velocity increases drastically from 0 to 50kmph and then after gaining maximum velocity it remains constant.

CVT Shaft Rpm:-

Study2:-

Case1:- Simulink model for Baja ATV with CVT using look up table

CVT Block:-

The only difference between this model and the first model is that in this model,the gear ratio input to CVT is provided using a lookup table.The vehicle velocity and shaft rpm outputs are same as before.

CVT Gear Ratio :-

LOOk UP TABLE VISUALISATION :-

OUTPUT For CASE1 :-

Vehicle Speed :-

STUDY2:-

Case2:-

SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE & DASHBOARD:-

Vehicle speed :-

The variations in vehicle velocity can be observed with change in throttle and brake inputs

CVT shaft RPM:-

Results:- Thus we have successfully analyzed 4 different models of BAJA ATV with CVT and recorded the outputs with respect to change in brake and throttle inputs.