Project

Aim: - Carry out a system-level simulation of an all-terrain vehicle.

Objectives: - Prepare a technical report explaining the model properties & comments on the results.

An all-terrain vehicle (ATV), also known as a light utility vehicle (LUV) a quad bike, or simply a quad, 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. As the name implies, it is designed to handle a wider variety of terrain than most other vehicles. Although it is a street-legal vehicle in some countries, it is not street-legal within most states, territories and provinces of Australia, the United States or Canada.

By the current ANSI definition, ATVs are intended for use by a single operator, although some companies have developed ATVs intended for use by the operator and one passenger. These ATVs are referred to as tandem ATVs.

Model Type: -

• BAJA ATV without dashboard.
• BAJA ATV with dashboard.
• BAJA ATV with lookup table.

FIRST: - BAJA ATV without dashboard.

Blocks Used

1. Signal Builder: - This block is used for generating signals for the brake, throttle, and CVT ratio inputs.
2. Generic Engine: - Represents a system-level model of spark-ignition and diesel engines suitable for use at initial stages of modelling 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.

1. Engine Sensor: - Used to determine RPM of engine crankshaft. Input of engine sensor is mechanical rotational conserving ports associated with the engine crankshaft & output goes to CVT blocks, as primary RPM to the variable gear ratio.

2.CVT Block: -

A continuously variable transmission (CVT) is an automatic transmission that can change seamlessly through a continuous 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 in automobiles, tractors, motor scooters, snowmobiles, bicycles and earthmoving equipment.

The most common type of CVT uses two pulleys connected by a belt or chain; however, several other designs have also been used at times.

Components comes under CVT block: -

• Variable ratio gear: - The Variable Ratio Transmissionblock represents a gearbox that dynamically transfers motion and torque between the two connected driveshaft axes, the base and the follower.

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.

• Input and output shaft Inertia: - The Inertia block represents an ideal mechanical translational inertia that is described with the following equation:

T=J.dw/dt

where:

T is inertia torque.

J is inertia.

ω is angular velocity.

t is time.

By default, the block has one mechanical translational conserving port. The block positive direction is from its port to the reference point. This means that the inertia torque is positive if inertia is accelerated in the positive direction.

• Ideal Rotational Motion Sensors: - Used to sense RPM of primary and secondary wheel of CVT.

5. Simple Gear: - Represents a fixed-ratio gear or gear box. No inertia or compliance is modelled in this block. You can optionally include gear meshing, backlash, and viscous bearing losses.

6. Vehicle Body: -

Vehicle Body subsystem consist of: -

• 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 modelled, 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

included, the physical signal port J accepts the inertia of the additional mass about its own CG

.

• Tyre

• Brake Shoes: -Represents a brake arranged as two pivoted rigid shoes symmetrically installed inside or outside a drum and operated by one actuator. The actuator force causes the shoes to exert a friction torque on a shaft connected to the drum.
• 

Connection S is a conserving rotational terminal associated with the drum shaft. Connection F is a physical signal port representing the force input to the actuator. Positive force creates friction torque that resists shaft rotation. Optionally include thermal effects and expose thermal conserving port H by setting Thermal port to Model.

Operation: -

1.Without dashboard

Throttle =1

brake input =0

CVT ratio

workspace for CVT ratio.

Primary and Secondary wheel RPM:

Velocity=60km/hr

velocity vs throttle:-

throttle=0.5 for 20 second and then rises to 1.2 after 20 sec. as per that velocity changes.

2.With Dashboard:-

2.With dashboard

1. You can use dashboard blocks to build an intuitive and interactive interface for your model. The control blocks, such as the Knobblock, connect to variables or tenable parameters in your model and allow you to interactively modify the value of the connected element during simulation. The display blocks connect to signals in the model and display the signal value during simulation. For more information, see Control Simulations with Interactive Displays.
2. CVT Model with dashboard image is sown below
3. Where used blocks are,

Knob: - To change the value of throttle and brake.

Circular gauge: - this is used for showing running speed and velocity of the vehicle to the driver.

At start of simulation brake applied is zero where as throttle is =1

At that time speed of primary and secondary of CVT is 5439 and 3793 RPM respectively& Velocity of vehicle is almost 59.4km/hr

Now throttle reduced to below 0.5 at that time

speed of primary and secondary of CVT: -3000 & 4000 RPM

velocity of vehicle is almost 40 km/hr

Now brake applied to the body

Throttle =0.99

Brake=0.50

Velocity of body = 29.2

speed of primary and secondary of CVT: -1859 & 2656 RPM.

CONCLUSION: -

Speed of CVT wheels is directly proportional to the throttle input.

velocity is also directly proportional to the throttle.

as brake applied spped and velocity both decreases.

LEARNING:-

Adding signal to data inspector.

Gain knowledge about diffrent dashboards.

Logging the singnals.

2.With Lookup table in dashboard model

Instead of usin gsignal bui;der here used lookup table with value defined in workspace which feed into the CVT block.

CONCLUSION: -

Speed of CVT wheels is directly proportional to the throttle input.

velocity is also directly proportional to the throttle.

as brake applied spped and velocity both decreases.

LEARNING:-

Adding data lookup table

Import new file to workspace related to its model.