Challenge

Project

RRakesh Thakur3 May 2022

Aim:- To prepare a technical report of an All - Terrain Vehicle (ATV) under the different conditions.

Objective:-

* To prepare a technical report of BAJA ATV model with and without lookup table.

Theory:-

ALL TERRAIN VEHICLE :

An ATV, or all-terrain vehicle, is a motorized off-highway vehicle with handlebars and a seat like a motorcycle, but with four tires that are optimized for control and safety when navigating unpaved roads. The term is more generally used to describe a number of small, open, motorized buggies and tricycles designed for off road use.

On an all-terrain vehicle, the rider sits upright and operates these vehicles like motorcycles, but the extra wheels give the rider more stability at slower speeds. ATVs are used for everything from racing and recreational riding to hunting, farming, hauling, plowing snow and even cutting the grass. Because of their small size and awesome power, they can be used for an unlimited number of duties.

CVT:
A CVT transmission, or continuously variable transmission, shifts seamlessly through an endless range of effective gear ratios as you drive, while other types of mechanical transmissions offer a fixed number of gear ratios and have hard shifts between each.

A CVT, or continuously variable transmission, shifts seamlessly through an endless range of effective gear ratios as you drive, while other types of mechanical transmissions offer a fixed number of gear ratios and as specified by Certified Transmission Repair. Tough changes occur between each. CVT transmission system is also known as single-speed, shiftless and Stepless transmission.

Procedure:-

* BAJA ATV Model Without Dashboard.

Brake And Throttle Input :

Brake inpu is constant i.e. zero throughout the time of 80sec. Throttle input is 0.3 for first 20sec, accelerates to 1 at the same and remains constant throughout the remaining time till 80sec.

Signal Builder:

The Signal builder block allows you to create linear signal sources and to use them in a model. You can quickly switch the signal groups into and out of a model to facilitate testing.

The CVT gear ratio 2:3 for the first 4sec , then drops down to 1.8 till 35 sec and remains constant thereafter till 80 sec.

Generic Engine:

It represents a model of spark-ignition and diesel engines suitable for use at initial stages of modeling when only the basic parameters are available. 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.

Engine Sensor:

Ideal Rotational Motion Sensor: The block represents an Ideal Rotational Motion Senso, that is a device that converts an across variable measured between two mechanical rotational nodes into a control signal proportional to angular velocity or angle. Connections R and C are mechanical rotational conserving ports and connections W and A are physical signal output ports for velocity and angular displacement, respectively.

CVT Subsystem:

Inertia:

The block represents an ideal rotational inertia. The block has one mechanical rotational conserving port. The block positive direction is form it's port to the reference point. This means that the inertia torque is positive if the inertia is accelerated in a positive direction.

Variable Ratio Transmission:

It represents a variable ratio gearbox such as implented 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 raotational conserving ports. Specify the relation between base and follower rotation directions with the output shaft rotates parameter.

Vehicle Body Subsystem:

Vehicle Body:

Represent two axle vehicle body in longitudinal motion. the block accounts for body mass, aerodynamic drag, road incline, and weight distribution between axle due to acceleration and road profile. The vehicle can have the same or a different number of wheels on each axle. Optionally include pich and suspention 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 develop by tires should be connected to this port. Connections V, NF, and NR are plysical signal output ports for vehicle velocity ad front and rear normal wheel forces, respectively. wheel forces are considered positive if acting downwards. Connections W and beta are plysical signal input ports corresponding to headwind and road inclination angle, respectively. If the variable mass in 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 it's own CG.

Tire:

Represents the longitudinal behavior of a highway tire characterized by the tire Magic Formula. The block is built from Tire road interaction (magic formula) and Simscape foundation library wheel and axle blocks. Optionally, the effects of tire inertia, stiffness, and damping can be included.

Connection A is the mechanical rotational conserving port for the wheel axle. Connection H is the mechanical translational conserving port for the wheel hub through which the thrust developed by the tire is applied to the vehicle. Connection N is a physical signal inut port that applies the normal force acting on the tire. The force is considered positive if it acts downword. Connections S is a physical signal output port that reports the tire slip. Optionally expose physical signal Magic Formula coefficients. Physical signal port M accepts a four-element vector corresponding to the B, C, D, and E Magic formula coefficients.

Double-Shoe Brake:

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.

Torque vs Speed characteristics:

Outputs:

* Vehicle speed

* CVT Shaft speed

BAJA ATV Model with Dashboard

A dashboard ( also called dash, instrument panel (IP), or fascia) is a control panel usually located directly ahead of a vehicle's driver, displaying instrumentation and controls for the vehicle's operation.

The initial conditions are as follows:

Brake input = 0

Throttle input = 0.3

It comprise a throttle and brake input through a knob which can be varied unlike the signal builder in the previous model without Dashboard. The Engine RPM gauge and velocity gauge displays the changes done by the respective knobs.

Outputs:

* Vehicle Speed

* CVT Shaft Speed

BAJA CVT using Lookup table

* Without Dashboard

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 retrives the corresponding output values from the table. If the lookup table does not explictly define the input values, Simulink can estimate an output value using interpolation, extrapolation, or rounding.