Project

AIM : To study the simulation of  baja all terrain vehicle atv model.

ATV : An all-terrain vehicle, also known as a light utility vehicle,  is a vehicle that travels on low-pressure tires, with a seat that is straddled by the operator, along with handlebars for steering control. 

CVT model one: 

The cvt model contains

1)Signal Builder:

    The Signal Builder block is used  to create interchangeable  linear signal sources and use them in a model.

2)Generic Engine :

    Can be used as spark  ignition and deisel engine .

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.

                                        Speed vector and Torque vector are the assigned parameters.

3)Engine Sensor:

    a)RPM sensor:  this block measures angular velocity or angle in a mechanical rotational network.Contains ports R,C,W,A.Physical signal ports W and A report the angular velocity and angle, respectively, of port R relative to port C. The measured angular velocity is positive when the angular velocity at port R is greater than the angular velocity at port C.

4)Simple Gear:

    Works as a gear box with fixed gear ratio where user can include gear meshing, backlash, and viscous bearing losses.

5)CVT subsystem:

  a)Inertia: The block represents an ideal mechanical rotational inertia.

 

  b)Variable 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.

6)Vehicle Body:

   

Represents a two-axle vehicle body in longitudinal motion. The block accounts for body mass, aerodynamic drag, road incline, and weight distribution between axles due to acceleration and road profile.

a)Tyre:

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.

b)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.

                                                             Torque vs Speed 

observation: From the above figure it is clear that torque is inverserly proportional to speed,i.e more the torque less the speed .

At 1st gear more torque is generated as more force is required to move vehicle from stable position.

Observations:

1) Velocity : at start it increases and after 40 sec it becomes constant through out as no breaks are applied.

2)Distance : as the vechile is moved the distance goes on increasing with respect to time .

3)Throttle: is constant at 0.5 throughout.

4)Breaks : NO breaks are applied.

PRIMARY AND SECONDARY RPM:

Whith Dashboard:

the major avdantage is throttle and break can be given by user during the simulation itself.

I tried to do the same by randomly changing the throttle input and following were results  where more the throttle more the speed was observed.

The nature of graph of primary and secondary rpm is quite similar to the graph(curve) of throttle.

CONCLUSION:

1)Velocity, CVT Shaft Speed and Engine Speed are directly proportional to the Throttle input and inversely proportional to the Brake input.

2)CVT Primary speed is greater than CVT Secondary speed as they are directly proportional to their shaft diameter.

3)The variation in vehicle velocity can be observed with change in throttle and brake inputs.