Project

Aim:  

To prepare a technocal 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 and comment on the results.

ALL TERRAIN VEHICLE:

An all- terrain vehicle (ATV) is defined as a motorized off-highway vehicle designed to travel in four low pressure or non-pneumatic tires, having a seat designed to be staddled by the operator and handlebars for steering control.

Study-1:

case-1

Simulink model for BAJA ATV with CVT model:

In the cvt model we use the no.of blocks in that one of the block is signal builder.

Signal Builder:  Signal Builder is used to give the throttle valu and breack input to the generic engine.

the major component in this model is continously variable transmission drive (CVT).

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 better acceleration while higher gears can maximize fuel economy. CVTs differ from traditional automatic transmissions in that they don't have gears that provides "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 groave in whivh the connecting belt rides. One side of the pulley is fixed, and the other side is movable, acurated 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 higer doing the walls of the pulley, depending on driving conditions, there by changing the gear ratio.

CVT Block:  In this block we have input shaft inertia and output shaft inertia. The input shaft inertia and ouput shaft inertia block are used to put the primary and secondary shaft at fixed position. and also we have the motion detection sensor/ wheels speed measuring sensor. This sensors are used to measure the primary and secondary wheels speeds in RPM.

VARIABLE TRANSMISSION RATIO:

It is represent  a variable ratio gearbox such as implemented by mechanical belt CVT, electric, or hydraulic transmissions. The physical signal input are "r" defined as the ratio of input to output angular shaft velocities.

Conections B(base) and F (followers) are the mechanical rotational conserving ports for primary and secondary shaft or wheels. Specify the relation between base and follower roration 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 availaible. Optional idle speed and redline controllers are included. The trottle input signal T lies between zero and one and specifies the torque demands from the engines as a fraction if 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.

 WITHOUT DASH BOARD

     In this model there is no variable throttle and breake inputs. It has only constant inputs through signal builder.

Output scope observations: 

In this simulink model at constant throttle input is 0.5 and at zero break input, The velocity of the vehicle is gradually increases and remain's constant and the displacement of the vehicle is gradually increases with the input values.

CVT Shaft speed:  In this graph the wheels has the primary and sencondary speed sensor. The speed sensor are mesure the speed o the wheels. In this graph we observe the difference between the primary and sencondary wheels speeds. the primary and secondary wheels speed are gradually increases with respect to inputs. here, the secondary wheel speed is greater than the primary speed.

WITH DASH BOARD:

In this simulink model we dont have the signal bulder block to provide the trottel and breake inputs. For inputs we have to control the both throttlrese and break inputs using the knobs in dashboards to get real time results. In the graph we observe the outputs (velocity, displacement , throttle input and breake input), CVT shaft speed

Output scope observations: 

At initially set the trottle Input=0.3 and breake input = 0 in the dashboard using the knobs. After setting the dashboard intial values we have to run the simulation model and varies the throttle and break inputs. when you increases the throttle value the vechicle velocicy is also incerase gradually with respect to the throttle inputs and when you applies the breake input the speed of the vehicle is decrease . here i observe the result once you applied the break input fully after that increase or decreased the trottle speed there is no changes the vehicle speed is zero

CVT Shaft speed:  In this graph the wheels has the primary and sencondary speed sensor. The speed sensor are mesure the speed o the wheels. In this graph we observe the difference between the primary and sencondary wheels speeds. the primary and secondary wheels speed are gradually increases with respect to inputs. here, the secondary wheel speed is greater than the primary speed.

Study-2:

case-1

SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE:

In the BAJA ATV Model we directly connect the feedback velocity input to the cvt. in this we have the lookup table to get the real time updates/resuls continously.

In the CVT Block the only difference between this model and the first model that in this models, the gear ratio input to CVT is provided using a lookup table. The vehicle velocity and shaft RPM outputs are same as before.

WITHOUT DASH BOARD

     In this model there is no variable throttle and breake inputs. It has only constant inputs through signal builder.

vehicle speed: 

In this simulink model get the inputs like throttle and brake input values from lookup table,once the model is un, The velocity of the vehicle is gradually increases 

CVT Shaft speed:  In this graph the wheels has the primary and sencondary speed sensor. The speed sensor are mesure the speed o the wheels. In this graph we observe the difference between the primary and sencondary wheels speeds. the primary and secondary wheels speed are gradually increases with respect to inputs. here, the secondary wheel speed is greater than the primary speed.

CVT Ratio: CVT Ratio of the model is seem like the lookup table figure. and the values are noted from the feedback velocity

WITH DASH BOARD:

vehicle speed: 

At initially set the trottle Input=0.3 and breake input = 0 in the dashboard using the knobs. After setting the dashboard intial values we have to run the simulation model and varies the throttle and break inputs. when you increases the throttle value the vechicle velocicy is also incerase gradually with respect to the throttle inputs and when you applies the breake input the speed of the vehicle is decreases and again repeat the process again the velocity of the vehicle is increases and decreases with respect to the variable inputs from the dashboard.

CVT Shaft speed:  In this graph the wheels has the primary and sencondary speed sensor. The speed sensor are mesure the speed o the wheels. In this graph we observe the difference between the primary and sencondary wheels speeds. the primary and secondary wheels speed are gradually increases with respect to inputs. here, the secondary wheel speed is greater than the primary speed.

CVT Ratio: CVT Ratio of the model is seem like the lookup table figure. and the values are noted from the feedback velocity.

CONCLUSION:

    Thus we have successfully analysed 4 different models of BAJA ATV WITH CVT and recorded the outputs (vehicle velocity & CVT shaft rpm) with repect to variations in inputs like throttle and brake.