Project

PROJECT

BAJA ALL TERRAIN VEHICLE

AIM-To study and analyze the BAJA ALL TERRAIN VEHICLE(ATV) model using simulink.

OBJECTIVE-To prepare a technical report of BAJA ALL TERRAIN model with and without lookup table.

THEORY-

ALL TERRAIN VEHICLE

An all terrain vehicle atv aloso known as a quad cycle,light utility vehicle (LUV),as define by the American National Institute(ANSI),is a vehicle

that travels on low pressure tires,with a seat that is saddeled by the operator,along with handle barsfor steering control.it is designed to handle

a wider variety of terrain than most other vehicles.

BAJA ATV(SAE):-

the baja SAE series is an event for the under-graduate students organized by the society of aN Automotive engineers,USA.the event originated

in the name of mini-baja,in the year 1976 at university of coroline.since,the event has spanned accrossed six countries-USA,mexico,south

africa,korea,brazil and India.the baja sae tasks the srudents to design,fabricate and validate a signal seater four wheeled off road vehicle

take in series of an event spread over a course of three days that test the vehicle for the sound engineering practices that have gone into it.

the agility of the vehicke in term of gradeability,spped,acceleration and manueverability.characteristics and finally its ability to endure that

back breaking durability test.

MAJOR COMPONENTS USED IN SIMULATION:-
GENERIC ENGINE:-
The generic engine block represent a general internal combustion (IC) engine,which is type of spark ingnition (SI)petrol or compression

ignition(CI- diesel).the speed torque and speed power parameters are provided.

ports:-
B-rotational conserving port representing the engine block.
F-rotational conserving port representing the engine shaft.
T-physical signal input port specifying the normalized engine throttle level.
P-physical signal output port reporting the instantaneousengine power in watts(W0.
FC-physical signal input port reporting the fuel consumption rate in kg/s.

SIMPLE GEAR-
the simple gear is a combination of a driver and a driven gear where the speed is reduced by the gear ratio.
the gear ratio is defined as,

ports:-

• B-base gear or driver gear.
• F-follower gear or driver gear.

CVT transmission :-

In CVT(continuous variable transmission),the variable diameter pulley plays a role in the transmission.variable-diameter pulleys must always

come in pairs,known as the drive pulley (driving pulley),is connected to the crankshaft of the engine.the driving pully is also called input

pulley because it's where the engine enters the transmission.the second pulley is called the driven pulley becaise the first pulley is turning

it.as an ouput pulley,the driven pulley transfer energy to the driveshaft.

the distance between the centre of the pulleys to where the belt makes contact in the groove is known as pitch radius.when the pulleys are

close together,the belt rides higher and the pitch radius increases.the ratio of the pitch radius on the driving pulley determines the gear when

the pitch radius is small on the driving pulley and large on the driven pulley,then the rotational speed of the driven pulley decreases,resulting

in a lower gear.when the pitch radius is large on the driving pulley and small on the driven pulley ,then the rotational speed of the driven

pulley increases,resulting in a higher gear.thus in a theory,a cvt has an infinite number of gears that it can run through at any time,at any

engine engine or vehicle speed.

PORTS:-

• B-base pulley or drive pulley.
• F-follwer pulley or driven pulley.
• R-variable transmission ratio(input).

VEHICLE BODY:-

Two axle vehicle with longitudinal dynamics and motion and adjustable mass,geometry,and drag properties.The vehicle can have the same or

different number of wheels on each exle.for example,two wheels on the front axle and one wheel on the rear axle.the wheels are assumed

identical in size.the vehicle can also have a center of gravity(CG) that is at or below the plane of travel.

PORTS:-

• NR-rear axle normal force
• NF-front axle normal force
• Beta-road incline angle (rad)
• V-longitudinal velocity(m/s)
• W-head wind speed(m/s)
• H-horizontal motion

DOUBLE SHOE BRAKE:-

The double shoe brake block represemts a frictional brake with two pivoted rigid shoes that press against a rotating drum to produce a

braking action.The rigid shoes sit inside or outside the rotating drum in a diametrical opposed configuration.A positive actuating force causes

the rigid shoes to press against the rotating drum.viscous and contact friction between the drum and the rigid shoe surfaces cause the

rotating drum to decelerate.

PORTS:-

• S-rotational conserving port associated with the rotating drum shaft.
• F-physical signal input port associated with the applied actuating force.

TIRES:-

The vehicle body is connected to 4 tires each per axle to move the vehicle according to the power input to the axle.

PORTS:-

• N-normal force
• S-tire slip
• A-axle
• H-mechanical translational port associated with the wheel hub that transmits the thrust generated by the tire to the remainder of vehicle

BLOCKS USED:-

Signal builder:-to input the brake,throttle and cvt ratio.

simulink to ps-converter:-to convert the simulink signal to simscape environment.

solver comfiguration:-to specify the solver parameters before starting the simulation.

mechanical reference:-to make sure all the components are clamped to the ground.

generic engine:-to run the engine with speed and torque values as input.

ps to simulink converter:-to convert simscape signal to simulink environment.

scope:-to view the graph of the parameters for better understanding.

display:-to view the calculated engine power.

inertia:-to represent the solid inertia.

rotational motion sensor:-to sense the rotational motion from the engine and give output as RPM.

variable gear ratio:-to vary the speed according to the gear ratios.

PS terminator:-terminator for unconnected physicl signal outputs.

double shoe brake:-to apply brake to the vehicle when needed.

PS constant:-generate constant physical signal.

Tire:-for transportation for the vehicle.

Rotational free end:-for mechanical component (tires).

vehicle body:-to represent the baja ATV model body.

custom measure gauge:-to measure the brake and throttle input.

knob:-to increase,decrease and vice-versa of throttle and brake inputs.

lookup table:-to insert the CVT values from the workspace.

simple gear:-to reduce the speed of the engine with pre-defined gear ratio.

Step-to increase or decrease an input value for a defined time interval.

TYPES OF MODEL:-

• BAJA ATV MODEL WITHOUT DASHBOARD.
• BAJA ATV MODEL WITH DASHBOARD.
• BAJA ATV MODEL -MAPPED LOOKUP TABLE WITH DASHBOARD.

BAJA ATV MODEL WITHOUT DASHBOARD

MAIN MODEL:-

BAJA ATV MODEL

ENGINE SENSOR:-

This block measures angular velocity or angle in a mechanical rotational network.the sensor is ideal since it does not account for inertia,

friction,delays,energy consumption, and so on.

the physical signal ports W and A report the angualr velocity and angular displacement,respectively,of port R relative to port C.the

measurement is positive when the motion at R is greater than the motion at C.

CVT system:-

vehicle body:-

simulation process:-

• the throttle signal is generated by signal buider block and inputted to generic engine.
• the torque and speed vector are inputted from MATLAB wprkspace.

• the engine will generate the output rpm whicch can be taken from the crankshaft output.this speed will be given to the ideal rotational motion sensor to sense the ouput rpm.
• the same output speed will be given to a simple gear where the gear ratio is '4'.
• then the output speed from the gear reducer will be given to the variable ratio transmission block(cvt).
• the cvt ratio is provided to the variable ratio transmission CVT block through signal builder.

• the speed is controlled by the variable CVT ratios and the controlled output speed is inputted to the vehicle axle.
• the bfrake is signal is generated by the signal builder and inputted to the vehicle body(doyble shoe btrake) for applying brake to axle.

• the power from the CVT is inputted to the axle and the vehicle accelerates according to the speed.
• then the velocity is taken as output from the vehicle body for further analysis.

OUTPUT:-

THE TORQUE SPEED PLOT:-

the torque and speed are inputted from the MATLAB workspace window to the generic engine block to generate the output RPM accordingly.

this plot is common for all the cases because its a default input to a engine.

BAJA ATV MODEL WITH DASHBOARD.

FLOW PROCESS:-

the model workflow process is as same as the process of BAJA ATV model without dashboard but the throttle and brake inputs are controlled

by the user with the knob.we are also replacing signal builder with two separate constant blocks for throttle and brake.

OUTPUT:-

The engine speed is generated according to the inputs like throttle,break,torque,and speed vectors.the runtime is not defined so that the

throttle and brake are controlled by the user.the step up is throttle and step down is break input.