Project
AIM-
To prepare a technical report of simulation of BAJA ALL-Terrain-Vechicle (ATV) under different conditions.
OBJECTIVES-
Carry out a system level simulation of an ALL-Terrain-Vechicle (ATV) and prepare a technical report explaining the model properties & comments on the results.
ALL-Terrain-Vechicle (ATV)-
An ALL-Terrain-Vechicle (ATV) is defines as a Motorized off-Highway vehicle designed to travel on four low-pressure or non pneumatic tyres, having a seat designed to be straddled by the operator and handlebars for steering control.
Study 1#
case1:
Simulink model for BAJA ATV with CVT-
Major components in the model:
Continously 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 gears can provide a better acceleration while higher gears can maximize fuel economy. CVTs differ that from traditional automatic transmissions in that they do not have gears that provides ''steps" between low and high speed operations. Instead of majority of them work via a pair of variable - diameter, cone-shaped pulleys is 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 hydrolic cylinder. The cylinder can increase or decrease the amount of space between the two sides of 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 GEAR RATIO-
Reprensents a variable ratio gearbox such as implimented by mechanical belt CVT, elctric, or hydraulic transmissions. The Physical signal input r defines the ratio input to output angular shaft velocities.
Connection 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 stage of modelling when the only basic parameters are available. Optional idle speed and red line controllers are included. The throttle input signal T lies between 0 and 1 specifies the torque demanded from the engine as fraction of the maximum possible torque.
Connection F & B are mechanical rotational conserving ports associated with the engine crankshaft and engine block, respectively. Connections P and FC are physical output ports through which engine power and fuel consumptions rate are reported.
INPUT SIGNAL-
A signal buider is used to create signals for brake and throttle.
CVT GEAR RATIO INPUT-
OUTPUT FOR CASE1:
Vehicle Speed-
It is cleared from the graph that the vehicle attains its maximum speed (v=55km/hr) at full throttle = 1 after 30 seconds and remains constant.
The break point value is zero and hence it has no effect on velocity.
CVT SHAFT RPM:
SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE & DASHBOARD:
In this model dashboard is used to control the inputs- Throttle & Brake with knobs.
OUTPUT FOR CASE-2
VEHICLE SPEED-
This graph is similar to that of cvt dashboard case. The variation in vehicle velocity can be observed with change in throttle and brake inputs. with increase in braking value, the speed of vehicle decreases. On the other hand, increasing the throttle leads to increased the vehicle velocity.
CVT SHAFT RPM:
This graph indicates the variation in RPM of primary and secondary shafts with respect to input parameters.
CONCLUSION:
Thus we have successfully analysed 4 differents Of BAJA ATV with CVT and recorded the outputs:- (Vehicle velocity & CVT shaft RPM) with respect to variations in input throttle and brake.