Project
Alm:
To prepare a technical report of Simulation of BAJA All-Terrain Vehicle (ATV) under different conditions.
Objectives:
Carry out a system-level simulation of an all-terrain vehicle and prepare a technical report explaining the model properties & comments on the results. An all-terrain vehicle (ATV) is defined as a motorized off-highway vehicle designed to travel on four low-pressure or
ALL TERRAIN VEHICLE:
non-pneumatic tires, having a seat designed to be straddled by the operator and handlebars for steering control
Major components in the model:
Simple Gaer:
simple gear Represents the 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.
Continuously Variable Transmission drive(CVT):
it is better to have more gears in a transmission, since it can optimize engine speed in a variety of driving conditions That means low goars can provide better acceleration while higher gears can maximize fuel economy. CVTs differ from traditional automatic transmissions in that they don't have gears that provide steps between low- and high speed operations. Instead, the majority of them work via a pair of variable-diameter, cone shaped pulleys connected by a steel or composite belt. The halves of each pulley are aligned with the pointed ends of the cones touching. These form a V-shaped groove in which the connecting belt rides. One side of the pulley is fixed, and the other side is movable, actuated by a hydraulic cylinder. The cylinder can increase or decrease the amount of space between the two sides of the pulley. This allows the belt to ride lower or higher along the walls of the pulley. depending on driving conditions, thereby changing the "gear ratio.
VARIABLE TRANSMISSION RATIO:
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.
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. Connections F and 8 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.
SETTING FOR THE VEHICLE BODY:
STUDY THE BAJA ATV MODEL WITH OUT A DASHBOARD
SIMULATINK MODEL:
CVT MODEL OF SET UP BLOCk:
VEHICLE BODY:
INPUT: one signal builder block is used to create a signal for throttle and brakes and another one is used to create the
needed cvt ratio
THROTTLE AND BRAKE INPUT:
when we applied the brake inputs are zero and the and the throttle input is zero from 0-10 sec after that it is one from
10-80 sec it is a given volue
CVT GEAR RATIO:
cvt gear ratio volues changes entirely over the period of time intially it is around 3.8 after that it is continiously decresing
and finally at a constant volue of 0.8
THE ENGINE TORQUE SPEED CHARACTERSTIC CAN BE GIVEN AS FOLLOW
OUT PUT RESULT OF AN THROTTLE AND BRAKES AS SHOWN BELOW
when the throttle is zero the speed gradually incresing and attains a naximum speed when the throttle is at one and
after that the throttle is constant and then speed is gradually decresing and finally the speed is in constant mode
the brake input is constant for entire region and hence it does not effect the velocity
CVT PRIMARY AND SECONDARY SPEED:
STUDY OF BAJA ATV MODEL WITH A DASH BOARD :
SIMULINK MODEL:
this model is same as the cvt model ,but here the input is given through the dash model there are two input one is
brake and the throttle both are connected to the constnant block which provide the input while the model is running for
infinite time this help us to create various scenarios while the simulation is running
ENGINE SENSOR:
the block represents an ideal mechanical roatational motion sensor that is a device that converts an across variable
measured betwen two mechanical roatational nodes into a control signal proportional to angular velocity or angle the
sensor is ideal since it does not account for inertia ,friction ,delay, energy consumption and so on.. connection r and c
are mechanical roatational conserving ports and connection w and a are physical signal output ports for velocity and
angular displacement respectively
CVT MAPPED MODEL:
OUTPUT:
CVT SHAFT SPEED:
ENGINE SPEED:
SPEED VECTOR:
TORQUE VECTOR:
LOOKUP TABLE VISUALIZATION:
