Project
Aim: To prepare a technical report of simulation of BAJAJ ALL-TERRAIN VEHICLE under different condition.
Objectives:
Carry out a system level simulation of an ALL-TERRAIN VEHICLE and prepare a technical report explaining the model properties.
Introduction:
ALL-TERRAIN VEHICLE(AVT) is defined as a motorizes off-highway vehicle designed to travel on four low pressure or non pneumatic tires,having a seat designed to be straddled by the operator and handlebars for steering control.
As the name implies, it is designed to handle a wider variety of terrain than most other vehicles.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 ATV.
STUDY-1
Model 1-Simulink model for BAJA ATV with CVT is attached in file(cvtmodel).By using simulink model of CVT consists of signal builder,generic engine,motion sensors,vehicle transmission,vehicle body,tyres and solver configuration blocks...
Major components in the model:
1.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.A continuously variable transmission is a transmission that operates on an ingenious pulley system that automatically varies the transmission ratio, allowing an infinite variability between highest and lowest gears with no discrete steps or shifts. CVTs provide more useable power, better fuel economy and a smoother driving experience than traditional transmissions that use gearboxes with fixed numbers of gear sets.A continuously variable transmission system is a type of automatic transmission in which an arrangement of pulleys and belts made it possible for a drive to achieve n-number of continuous gear ratios within a range.
2.Variable Transmission Ratio:
Represents a variable ratio gearbox such as implemented by mechanical beltCVT,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.
3.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 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.
INPUT SIGNAL:
A Signal builder is used to create signals for brake and throttle.
CVT Gear Ratio Input:
Torque vs Engine Speed Input:
VEHICLE BODY:
OUTPUT FOR MODEL 1
VEHICLE SPEED:
It is clear from the graph that the vehicle attains its maximum speed (V = 55km/hr) at full throttle = 1 after 30 seconds and then remains constant. The brake input value is zero, hence it has no effect on velocity.
CVT SHAFT RPM:
These graphs shows the variation in angular velocities of input and output shafts of the variable gear transmission system. These values differ with respect to the gear ratio.
MODEL 2
SIMULINK MODEL FOR BAJA ATV WITH CVT USING DASHBOARD
A model is attached in file (cvtmodeldashboard).
In this model we have a dashboard which contains knobs to control the inputs. In this case, the inputs- ‘Throttle’& ‘Brake’ are not provided using signal builder. A knob is provided to control both the parameters in real-time for the user.
OUTPUT:
VEHICLE SPEED:
It can be observed from the graph that the velocity of the vehicle increases drastically from 0 to 50kmph when throttle value is 0.5 & brake input is 0. Once the braking value increases from 0.1 to 0.5, the velocity of the vehicle decreases to 0 at constant throttle value.This explains the direct relation of vehicle velocity with respect to throttle and brake inputs.
CVT SHAFT RPM:
STUDY 2
MODEL 3
SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE:
CVT GEAR RATIO:
LOOK UP TABLE VISUALISATION:
OUTPUT:
VEHICLE SPEED:
CVT SHAFT RPM:
Both results are same as that of the first case: - SIMULINK MODEL FOR BAJA ATV WITH CVT since the input parameters are same.
MODEL 4
SIMULINK MODEL FOR BAJA ATV WITH CVT USING DASHBOARD & LOOKUP TABLE:
In this model a dashboard is used to control the inputs- ‘Throttle’ & ‘Brake’ with knobs.
OUTPUT:
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 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 different models of BAJAJ ATV WITH CVT and recorded the outputs: - (Vehicle velocity & CVT shaft rpm) with respect to variations in input throttle and brake.