Project

AIM:

To prepare a technical report of a simulation of BAJA All-Terrain vechile (AVT) under different conditions.

OBJECTIVE:

Carry out a system-level simulation of an all-terrain vechile and prepare a technical report explaining the model properties and comments on the results.

ALL-TERRAIN VECHILE:

An all-terrain vechile is defined as a motorized off-highway vehicle designed to travel on four low pressure tires, having a seat designed to be straddled by the operator and handlebars for steering controls.

CASE1:

SIMULINK MODEL FOR BAJA AVT WITH CVT:

COMPONENTS USED IN THE MODEL:

Continuously variable Transmission drive(CVT)

• Primary pully
• variator
• secondary pully
• belt

WORKING:

In a CVT there is a primary pully and secondary pully which is connected with a belt and there is variator for both the pullys. If a primary pully moves outwards then the secondary pully moves inwards,

Rp < Rs

which is, radius of a primary pully is more then radius of a secondary pully is called speed reduction.

similarly,

primary pully moves inwards and a secondary pully moves outwards then, primary pully radius is less then a radius of a secondary pully that is Overdrive.

Rp > Rs

CVT BLOCK:

Input shaft inertia is connected with a primary pully and output shaft inertia is connected with secondary pully. To specify the gear ratio we have variable gear ratio. The CVT primary RPM and CVT secondary RPM acts like sensor and gives RPM values.

GEAR RATIO:

As 3840 is the maximum RPM of BAJA vehicle and it is the highest value and so the gear ratio stops at 3840 since it has no value.

VARIABLE TRANSMISSION RATIO:

Represents a variable ratio gearbox such as implemented by mechanical belt CVT,electric or hydraulic transmission. The physical signal input r defines the ratio of the input to output angular shaft velocities.

connections B (base) and F (follower) are mechanical rotational conserving ports. specify the relation between base and follower directions with the output shaft rotates parameter.

ENGINE:

Represents a system level model of spark ignation and diesel engines suitable for use at initial stages of modelling when only the basic parameters are available. Optional idle speed and redline controllers are included in throttle input signal T lies between zero and one and specifies the torque demanded from the engine as a fraction of the maximum possibe torque.

Connections F and B are mechnical rotational conservating ports are associated with the engine cranshaft and engine block.

INPUT SIGNAL:

A signal builder is used to build signals for breake an throttle.

It is clear from the graph that the vehicle attains its maximum speed V=65km/hr at full trottle = 1 after 50sec and remains constant. The break input value is zero, hence it has no effect on velocity.

CVT SHAFT RPM:

These graph shows the in angular velocities of input and output shafts of the variable gear transmission system. These values differ with respect to gear ratio.

CASE2:

SIMULINK MODEL FOR BAJA AVT WITH CVT USING DASHBOARD:

In this model we have dashboard which contains knobs to control the inputs, In this case the inputs throttle and break are not provided using signal builder.

OUTPUT :

VEHICLE SPEED:

To run a simulation in initial stage throttle value is 0.5 and the break value is 0. This explains the vehicle velocity with respect to throttle and break inputs.

CVT SHAFT RPM:

CASE 3:

SIMULINK MODEL FOR BAJA AVT WITH CVT USING LOOKUP TABLE:

CVT BLOCK:

The gear ratio input to CVT is provided using lookup table.The vehicle velocity and shaft rpm are same as before.

CVT GEAR RATIO:

LOOKUP TABLE VISUALISATION:

OUTPUT:

VEHICLE SPEED:

CVT SHAFT RPM:

Both the result are same as that of firdt case simulink model for baja avt with cvt since the models are same.

CASE4:

SIMULINK MODEL FOR BAJA CVT WITH AVT USING LOOKUP TABLE AND DASHBOARD:

In this model as a dashboard is used so throttle and breaks are used as an input.

OUTPUT

VEHICLE SPEED:

The variation in vehicle speed is observed by changing the throttle and break inputs. As a break value increase speed of vehicle decreases and when break value decreases speed of vehicle inceases. Increased throttle input increases speed velocity.

CVT SHAFT RPM:

This graph represents variation in primary and secondary shaft with respect to input prameters.

CONCLUTION:

We have succusfully analysed four different models of BAJA AVT WITH CVT and outputs are recorded with respect to throttle and break inputs.