Project

AIM:

TO CARRY OUT A SYESTEM LEVEL SIMULATION OF A BAJA ATV

OBJECTIVES:

• Analyse all components and understand the relation and flow between the blocks
• understand the different types of wayes to model this BAJA ATV.

AN ATV IS A SMALL MOTOR VEHICLE WITH THREE OR FOUR LOW PRESSURE TIRES DESIGNED FOR USE ON VARIOUS TYPES OF TERRAIN.RECREATIONAL ACTIVITIES IN DESERTS ARE USUALLY CARRIED OUT IN ATVS.THIS PROJECT IS IN REFERENCE TO ONE OF THE TYPES OF ATVS USED IN BAJA SAE COMPETITIONS.

• FROM THID MODEL,THE COMPONENTS PRESENT ARE:

• ATV::INPUT BLOCKS-----BREAK ,,THROTTLE ,,CVT GEAR RATIO
• GENERIC ENGINE:::ENGINE SENSOR,,,SIMPILE GEAR
• CVT:::VARIABLE GEAR RATIIO,,,SHAFT INERTIA
• VEHICLE BODY:::WHEELS,,PHYSICAL BODY,,,SHOE BREAKS

BREAKJ AND THROTTLE INPUT:::

• NO BREAKS IS PROVIDED
• A CONSTANT THROTTLE of 0.3 for the first 20 seconds,,and full throttle of 1 for the remaining
• These two parameters are fed into the engine

GENERIC ENGINE::;

• The engine uses a programmed relationship between speed and tourqe,,,modulate by the throttle signal..The throttle input is seen above and the speed-torque data points are extracted from the graph
• Crankshaft is connected to an engine sensor,,which simply senses the angular velocity and angular displacement of the crankshaft

CONTINUOUSLY VARIABLE TRANSMISSTION(CVT)

• AS EVIDENT IN THE MEDIA ABOVE,, TWO CONE-SHAPED PULLEYS CONNECTED BY A STEEL OR COMPOSITE BELT,,WHOSE DIAMETERS ARE CONTINUOUSLY VARIABLE,,WORK TOGETHER TO PROVIDE INFINITE GEAR RATIOS
• OPTIMIZING ENGINE SPEED IN A VARIETY OF ROAD CONDITIONS,,ACCORDING TO THE SPEED AND TORQUE REQUIREMENTS OF THE TERRAIN.

CVT subsyestem blocks::;

• the input and output shaft inertia represent primary pulley(driver),,and secondary pulley(driven) respectively
• TWO ROTATIONAL MOTION SENSORS ARE FOR TRACKING THE ANGULAR VELOCITIES OF THE TWO PULLEYS.

VEHICLE BODY SUBSYESTEM BLOCKS::::

• THE VEHICLE BODY ACCOUNTS FOR BODY MASS,AERODYNAMIC DRAG,ROAD INCLINE,AND WEIGHT DSTRIBUTION BETWEEN AXLES DUE TO ACCELERATION AND ROAD PROFILE.
• THE DOUBLE-SHOE BREAK IS TO APPLY BREAKES TO THE REAL WHEELS.. WITH THIS COMPONENT,TWO BREAK BLOCKS ARE APPLIED AT OPPOSITE ENDS OF THE DRUM.THIS PREVENTS AN UNBALANCED FORCE FORM ACTING ON THE SHAFT AND BEARING CONNECTING THE DURM TO THE WHEEL,WHICH WOULD BE THE CASE WITH A SIGNAL-SHOE BREAK.

BAJA ATV MODEL LOOKUP TABLE::;;;

• THE ONLY DIFFERENCE WITH THIS STUDY IS THAT THE CVT GEAR RATIO ISN'T FED IN VIA A SIGNAL BUILDER,BUT INSTEAD VIA A LOOKUP TABLE
• THE LOOKUP TABLE IS DATA REGARDING THE RELATION BETWEEN CVT GEAR RATIO AND VEHICLE SPEED,WHICH IS INCORPORATED THROUGH A SIMPLE MATLAB SCRIPT.

CONCUSION::;:::::---------

• THE BAJA ATV WITH CVT WAS MODELLED USING TWO MAIN STUDIES. WITH THE FOCUS PULLEY ON CVT,THIS PROJECT IS ABLE TO SHOW THE EFFECT OF CVT ON VEHICLE VELOCITY,ALTHOUGH MULTIPLE SITUATIONS FOR DIFFERENT MODELS OF ATV DESIGN......