Project

AIM: To Study and analyze the BAJA All Terrain Vehicle (ATV) model using Simulink.
OBJECTIVES:
To prepare a technical report of Baja TV model with and without Lookup Table.

THEORY:

ALL TERRAIN VEHICLE:
An All-Terrain Vehicle (ATV), also known as a quad(cycle), Light Utility Vehicle (LUV), as defined by the American National Standards
Institute (ANSI), is a vehicle that travels on low-pressure tires, with a seat that is straddled by the operator, along with handlebars for steering
control. It is designed to handle a wider variety of terrain than most other vehicles.

BAJA.ATVI(SAE):

The BAJA SAE series is an event for the undergraduate engineering students, organized globally by the Society of Automotive Engineers,
USA The event originated in the name of Mini - BAJA, in the year 1976 at University of Caroline. Since then, the event has spanned across
six countries - USA, Mexico, South Africa, Korea, Brazil and India. The BAJA SAE tasks the students to design, fabricate and validate a single
seater four - wheeled off road vehicle to take part in series of events spread over a course of 3 days that test the vehicle for the sound
engineering practices that have gone into it, the agility of the vehicle in terms of gradeability, speed, acceleration and maneuverability
characteristics and finally its ability to endure that back breaking durability test.

MAJOR COMPONENTS USED IN THIS SIMULATION:

GENERIC ENGINE:
The Generic Engine block represents a general Internal Combustion (IC) Engine, which is a type of Spark Ignition (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 Crankshaft
T- Physical signal input port specifying the normalized engine throttle level
P- Physical signal output port reporting the instantaneous engine power, in Watts (W)
• FC- Physical signal input port reporting the fuel consumption rate, in ke/s

SIMPLE GEAR:
The simple gear is a combination of a driver and 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 vital role in transmission. Variable - diameter pulleys
must always come in pairs. One of the pulleys, known as the drive pulley (or driving pulley), is connected to the crankshaft of the engine.
The driving pulley is also called the input pulley because it's where the energy from the engine enters the transmission. The second pulley is
called the driven pulley because the first pulley is turning it. As an output pulley, the driven pulley transfers energy to the driveshaft.
The distance between the center of the pulleys to where the belt makes contact in the groove is known as the 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 to the pitch
radius on the driven 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 theory, a CVT has an infinite
number of "gears" that it can run through at any time, at any engine or vehicle speed.

Ports:
• B- Base pulley ore Drive Pulley
• F- Follower 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 t
the same or a different number of wheels on each axle. For example, two wheels on the front axle and one wheel on the rear axle. The
vehicle 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 (N)
• NF - Front Axle Normal Force (N)
• Beta - Road Incline Angle 9rad)
• V- Longitudinal Velocity (m/s)
• W- Head Wind Speed (m/s)
• H- Horizontal Motion

DOUBLE SHOE BRAKE:
The Double-Shoe Brake block represents 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 diametrically 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

TIRE:
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 the
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 Configuration - 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 physical signal outputs.
•Double Shoe Brake - To apply brake to the vehicle when needed.
•PS Constant - Generate constant physical signal.
•Tire - For transportation of the vehicle.
•Rotational Free End - For mechanical component (Tire)
•Vehicle Body - To represent the BAJA TV 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 TV model without Dashboard
•BAJA ATV model with Dashboard
• BAJA TV model - Mapped Lookup Table with Dashboard

BAJA TV MODEL WITHOUT DASHBOARD

MAIN 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 angular 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 builder block and inputted to generic engine,

.The torque and speed vector are inputted from the MATLAB workspace.

• The engine will generate the output rpm which can be taken from the crankshaft output. This speed will be given to the Ideal Rotational
• Motion Sensor to sense the output rpm.
• The same output speed will be given to a simple gear mechanism to reduce the speed 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 VT ratio is provided to the Variable Ratio Transmission (VT) block through Signal Builder.

• The speed is controlled by the variable VT ratios and the controlled output speed is inputted to the vehicle axle.
• The brake signal is generated by the signal builder and inputted to the vehicle body (Double Shoe Brake) for applying the 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:

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 it's a default input to the engine.

ENGINE-SPEED-PLOT:

Here we can see the engine rpm generated accordingly w.rit to the throttle, speed and torque inputs.

ENGINE SPEED VS GEAR REDUCTION SPEED PLOT:

Here we can see that the engine speed is reduced by the Gear Ratio "4: For verification I calculated the maximum RPM.
Maximum RPM (Before Reducing) = 3833 rpm
Gear Ratio = 1:4
We know that,
Driven = 3833/4
Driven = 95625RPM
Thus, the reduced maximum rpm is 958.25rpm which can be verified from the plot.
Note: Driven = Secondary CVT Shaft.

Driver = Primary CVT Shaft.

CVT SPEED REDUCTION PLOT:

The engine reduced speed is controlled by various VT ratios. For verification I had calculated the maximum RPM.

Maximum RPM (Before Reducing) = 958.25rpm
CVT Ratio = 1:1.8
We know that,
Driven = 3833/ 4
Driven = 95625RPM
The reduced maximum rpm is 532.36rpm which can be verified from the plot.

SPEED VS THROTTLE PLOT:

From the graph we can infer that the brake is not applied during the drive cycle and the Throttle is constant (0.3) till 20 sec and being
increased from 0.3 to 1 from 20 sec where it remains constant for the rest of the run. With the increase in throttle, the vehicle speed also
increases.

ACCELARATION PLOT:

From the above plot, we can infer that the vehicle is accelerated from O-20kmph and then gradually increases till 30kmph(approx.) and it's
accelerated to 55.74kmph where it remains constant throughout the cycle.

BAJA ATV MODEL WITH DASHBOARD:

MAIN MODEL:

DASHBOARD:

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:

ENGINE SPEED PLOT:

ENGINE SPEED PLOT:

Here 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 Break are controlled by the user. The step up is throttle and step down are break inputs.

ENGINE SPEED VS GEAR REDUCTION PLOT:

Here we can see that the engine speed is reduced by the Gear Ratio '4. For verification I calculated the constant RPM (42000
50000 sec).
Maximum RPM (Before Reducing) = 2759.3 rpm
Gear Ratio = 1:4
We know that,
Driven = 2759.3/4
Driven = 689.825 RPM
The reduced constant rpm is 689.825 rpm which can be verified from the plot.

CVT SPEED REDUCTION PLOT:

The engine reduced speed is controlled by various VT Ratios. For verification I had calculated the constant RPM (42000 - 50000 sec)
Maximum RPM (Before Reducing) = 689.825 rpm
CVT Ratio = 11.8
We know that,
Driven = 689.825/1.8
Driven = 383.23 RPM
The reduced maximum rpm is 383.23 rpm which can be verified from the plot.

SPEED VS THROTTLE PLOT:

From the graph we can infer that the vehicle is accelerating while throttle is applied (Step Up) and decelerated while break is applied (Step
Down).

ACCELERATION PLOT:

From the graph we can infer that the vehicle is accelerated to 46 kmph initially and then the state changes when the user controls th
throttle and brake knobs. The step-up and step-down are acceleration and deceleration respectively. The linear one is the constant st
no changes in throttle or braking.

BAJA ATV MODEL:MAPPED LOOKUP TABLE WITHOUT DASHBOARD:

SIMULINK MODEL:

DASHBOARD MODEL SIMULATION OFF:

DASHBOARD MODEL SIMULATION ON:

FLOW PROCESS:

• The workflow process is same as the process of "BAJA TV model with Dashboard: The small addition is here the VT Ratio and
Vehicle Speed are extracted using To Workspace block.

WORKSPACE BEFORE:

• Instead of a Signal Builder block for CVT Ratio, the 2-D Lookup Table is used. The interpolation and extrapolation methods are set to
linear.

• Right Click on the Lookup table block and choose Foundation Library option and then Plot option to visualize the lookup Table.

RELATIONSHIP OF CVT RATIO,THROTTLE AND BRAKE INPUT:

In this BAJA ATV Model, the Engine is pre-set to run at 3300rpm with the throttle value of 'O.3. And the velocity at 45 m/s. The CVT
Ratio for minimum and maximum speed of the engine was pre-defined as 2.3 and 1.8 respectively. When the simulation is started the initial
throttle value 0.3 is achieved so that the CVT Ratio is nearby to 1.85. When the throttle is being increased the CVT Ratio move towards 1.8
where the state is maximum engine speed. Simultaneously when the throttle is decreasing the VT Ratio will move towards 1.85. While the
braking is applied the CVT Ratio increases so that it can achieve the nearest state of 2.3 (Minimum Engine Speed). When braking is reduced
the CVT Ratio move towards 1.85 which is the basic throttle input 0.3 or if any other throttle value is applied it would reach that CVT Ratio
state.

CVT RATIO PLOT:

OUTPUT:

ENGINE SPEED PLOT:

From the graph we can infer that the vehicle was first running at minimum rpm of 3300 rpm and then throttle is applied (step-up) then
braking (step-down) then brake is released so that engine rpm is increased then braking is applied. Finally throttle and brake are put to
constant of 2900 rpm.

CVT SPEED PLOT:

From the above graph we can understand that the throttle is applied (step-up) and then kept constant, then braking is applied (step-down),
and finally brake is released so that the engine speed is increased with the increase in throttle input.

INPUT VS VEHICLE SPEED:

From the plot we can infer that when throttle is applied the vehicle speed increases and when brake is applied, vehicle speed decreases
simultaneously.

SIMULINK MODEL:https://drive.google.com/drive/folders/1CQ5LTWzctiMA4jnja_D-yRqNlySqZuB4?usp=sharing