Project

AIM:
The aim of the project is to create the technical report of simulation of BAJA All-Terrain Vehicle(ATV) under different condition.
THEORY:
ALL-TERRAIN VEHICLE(ATV):
INTRODUCTION:
An all-terrain-vehicle (ATV) ,also known as quad,as defined by the American National Standards Institute(ANSI) is a vehicle
that travels on low -pressure tyres,with a seat that is stralled by the operator,along with the handelbars for steering control.As the
name implies,it is designed to handel a wider range of terrain than most other vehicles.All-terrain vehicles have been increasing in
popularity during the past decade.The motor driven,all-terrain vehicle are capable of cross-country travel without benifits of a road
or trail.Depending upon the tyre,an all-terrain vehicle may travel on land,snow,ice,marsh,swampland,or other natural terrain.
HISTORY:
1. ATVs were developed in Japan so that isolated farmers could transport their crops and supplies accross rugged terrain.Their
popularity spread to the United states and Canada.In 1969,Honda introduced the All Terrain Cycle(ATC) in the united states.The
ATC had three fat wheels and was promoted as a recreational vehicle.
2. After 1988,ATVs fell somewhat out of favor as a recreational vehicle because of consumer products safety commission
report.ATV riders were involved in a disproportionately high number of injury accidents due to rider immaturity,inexperience,and
lack of safety training.
3. More recently,a new generation of recreational riders,with a growing awareness of safety,has rediscovered the fun of ATVs.
4. While newer ATVs may have better safety features thab 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 for their maneuverability and off-roading ability.These include:
1. Border patrol
2. Construction
3. Emergency medical services
4. Land management
5. Law enforcement
6. Military Mineral exploration
7. Oil exploration
8. Pipeline transport
9. Search and rescue operations
10. Small-scale forestry
11. Surveying
12. Wild land fire control and so on...
CONTINUOUSLY VARIABLE TRANSMISSION:
A CVT is an automatic transmission that can change seamlessly through a continous range of gear ratios.This contrasts with
other transmissions that provide a limited number of gear ratios in fixed steps.The flexibility of a CVT with suitable control may allow
the engine to operate at a constant RPM while the vehicle moves at varying speeds.CVTs are used
automobiles,tractors,motorscooters,snowmobiles,and earthmoving equipment. The most common typr of CVT uses two pulleys
connected by a belt or chain,however several other designs have also been used at times.
The above figure consists of primary pulley,variator,secondary pulley and a belt,when variator which is connected to the primary
pulley move outwards then variator of secondary pulley will move inwards such that radius of primary pulley is less than the radius of
secondary pulley which leads to speed reduction and when variator which is connected to the primary pulley move inwards then
variator of secondary pulley will move outwards such that radius of primary pulley is more than the radius of secondary pulley which
leads to overdrive.
BAJA ATV Model:
The input signal is provided using signal builder in which brake input is provided as 0 and trottel input is provided as 0.3 upto 20sec
and varied to 1 for remaining seconds.
GENERIC ENGINE:
Represents a system-level model of spark-ignition and diesel engines suitable for use at initial stages of modeling when only
the basic parameters are available. Optional idle speed and red line controllers are included.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. If the engine speed
falls below the Stall speed, the engine torque is blended to zero. If the engine speed exceeds the Maximum speed, the simulation
stops and issues an error message.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.
The value of speed vector and torque vector is obtained from the diagram and logged the values in the workspace of matlab file.
ENGINE SENSOR:
Engine sensor which sense the rpm of the engine and it is connected to the CVT block

CVT BLOCKSET:
Input shaft represents the primary pulley and output shaft represents the secondary pulley and mechanical rotational sensor is
connected to input and output shafts and Variable ratio Gear represents a variable ratio gearbox such as implemented by mechanical belt CVT, electric, or hydraulic transmissions. The physical signal input r defines the ratio of input to output angular shaft
velocities.Connections B (base) and F (follower) are mechanical rotational conserving ports. Specify the relation between base and
follower rotation directions with the Output shaft rotates parameter.CVT ratio is generated by signal builder.
CVT ratio:
SIMPLE GEAR:
The output from the CVT block is connected to the simple gear which represents a fixed-ratio gear or gear box. No inertia or
compliance is modeled in this block. You can optionally include gear meshing and viscous bearing losses.Connections B (base) and F
(follower) are mechanical rotational conserving ports. Specify the relation between base and follower rotation directions with the
Output shaft rotates parameter. Optionally include thermal effects and expose thermal conserving port H by setting Friction model to
a temperature-dependent setting.
VEHICLE BODY:
Represents a two-axle vehicle body in longitudinal motion. The block accounts for body mass, aerodynamic drag, road incline,
and weight distribution between axles due to acceleration and road profile. The vehicle can have the same or a different number of
wheels on each axle. Optionally include pitch and suspension dynamics or additional variable mass and inertia. The vehicle does not move vertically relative to the ground.Connection H is the mechanical translational conserving port associated with the horizontal motion of the vehicle body. The resulting traction motion developed by tires should be connected to this port. Connections V, NF, and
NR are physical signal output ports for vehicle velocity and front and rear normal wheel forces, respectively. Wheel forces are
considered positive if acting downwards. Connections W and beta are physical signal input ports corresponding to headwind speed
and road inclination angle, respectively. If variable mass is modeled, the physical signal input ports CG and M are exposed. CG
accepts a two- element vector representing the x and y distance offsets from vehicle CG to additional load mass CG. M represents
the additional mass. If both variable mass and pitch dynamics are included, the physical signal port J accepts the inertia of the
additional mass about its own CG.
In Vehicle Body parameter block we can vary the mass of the vehicle and plot the result in data inspector in order to compare the
behaviour of vehicle during different mass condition.
RESULTS:
VEHICLE SPEED:
The above plot shows that when trottle is at 0.3 for 20sec speed of vehicle is increases correspondingly and at full trottle that is at 1
the vehicle speed is jumped nearly to 40kmph and then increases proportionally.
CVT SHAFT SPEED:
From the above plot it can be observed that the CVT secondary RPM plot and the velocity of the vehicle from the previous plot
behaves same because the secondary pulley is connected to the vehicle output.
Now from simulation data inspector ,
In the above plot red plot represents the vehicle with 100kg mass and blue plot represents the vehicle with 250kg mass and from the
plot it is clear that lighter the vehicle , maximum speed can be obtained and it is clear from the plot that the velocity of vehicle with a mass of 100kg is slightly more than the velocity of vehicle with a mass of 250kg.
BAJA ATV MODEL WITH LOOKUP TABLE:
The above model of Baja ATV with CVT along with the lookup table is similar to the previous model which includes generic engine
,CVT, simple gear,engine sensor,Vehicle body the only difference is that the CVT ratio is provided in lookup table.
LOOKUP TABLE:
A lookup table is an array of data that maps input values to output values, thereby approximating a mathematical function.
Given a set of input values, a lookup operation retrieves the corresponding output values from the table. If the lookup table does not
explicitly define the input values, Simulink can estimate an output value using interpolation, extrapolation, or rounding,
where:
An interpolation is a process for estimating values that lie between known data points.
An extrapolation is a process for estimating values that lie beyond the range of known data points.
A rounding is a process for approximating a value by altering its digits according to a known rule.
A lookup table block uses an array of data to map input values to output values, approximating a mathematical function. Given input
values, Simulink performs a lookup operation to retrieve the corresponding output values from the table. If the lookup table does not
define the input values, the block estimates the output values based on nearby table values.
The look up table data is logged into the workspace of the MATLAB
CVT ratio data:
Vehicle speed data:
The input to the model is brake and trottle which is provided by step time which depends on the run time and it varies accordingly.By
using loopup table for the gear ratio and it gives input to the CVT block and in this model the input values is obtained from the lookup
tables and accordingly to the values of input,the output value is obtained.
CVT BLOCK:
Input shaft represents the primary pulley and output shaft represents the secondary pulley and mechanical rotational sensor is
connected to input and output shafts and Variable ratio Gear represents a variable ratio gearbox such as implemented by mechanical belt CVT, electric, or hydraulic transmissions. The physical signal input r defines the ratio of input to output angular shaft
velocities.Connections B (base) and F (follower) are mechanical rotational conserving ports. Specify the relation between base and
follower rotation directions with the Output shaft rotates parameter.CVT ratio is obtained from the lookup table.
RESULTS:
VEHICLE SPEED:
The above plot shows that when trottle is at 0.3 for 20sec speed of vehicle is increases correspondingly and at full trottle that is at 1
the vehicle speed is jumped nearly to 40kmph and then increases proportionally and the result remains same as the input parameter
remains same.
CVT Shaft speed:
From the above plot it can be observed that the CVT secondary RPM plot and the velocity of the vehicle from the previous plot
behaves same because the secondary pulley is connected to the vehicle output
CVT RATIO:
The above data is obtained from lookup table.
BAJA ATV MODEL WITH DASHBOARD:
The study is based on 'BAJA ATV with dashboard' as shown in the figure above here input data like trottel and brake input is given
from the dashboard instead of providing the signals through signal builder and all the remaining blocks are same.The main purpose
of using dashboard is to study the output value with the variation of input data of throttle and brake in the digital reading.
CVT ratio:
RESULTS:
VEHICLE SPEED:
The above plot shows the variation of throtle as provided in the dashboard and corresponding velocity of the vehicle.
ENGINE RPM:
CVT SHAFT SPEED:
From the above plot it can be observed that the CVT secondary RPM plot and the velocity of the vehicle from the previous plot
behaves same because the secondary pulley is connected to the vehicle output.
BAJA ATV MODEL WITH DASHBOARD AND LOOKUP TABLE: