Project

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AIM: To study the system level simulation of an All-Terrain Vehicle (ATV) Model under different condition

KEYWORDS: CVT, lookup table, Dashboard, Baja ATV Model

SOFTWARE: Matlab, Simulink

OBJECTIVE:

1. Study the Baja ATV model without dashboard.
2. Study the Baja ATV model with dashboard.
3. Study the Baja ATV model using lookup table without dashboard.
4. Study the Baja ATV model using lookup table with dashboard.

CASE 1:

By using simulink model of CVT consists of Signal builder, generic engine, motion sensors, vehicle transmission, vehicle body,tyres and solver configuration blocks etc., as shown in figure-1. The CVT subsystem includes Transmission block, input and output shaft inertia and motion sensors as shown in figure-2. The vehicle body subsystem includes vehicle body block, double drum brake and tyres as shown in figure-3. The initial engine speed is given as 2100 rpm, mechanical rotation for driven pulley and driver pulley as 0.8 & 0.7 respectively. The mass of the vehicle as 250kg and 2 axles which connects 4 wheel accordingly.

CASE 2:

The above figure shows 'Baja ATV with dashboard' model which consists throttle meter and brake input in the dash board instead of giving input through signal builder. Rest of the blocks and subsystems are common in the above Baja ATV model without dash board as shown in figure 2 & figure 3. The main concept of using dash board is study the result by varying the input of brake and throttle, which shows that the velocity and speed of the engine. The gear ratio is maintained as 2.3 for 5 secs and linearly decreases to 1.8 and maintained constant for overall simulation as shown in figure 5. As the brake input varies from 0 - 0.5, the velocity and speed decreases accordingly. By increasing the throttle, the velocity and speed of the engine & shaft increase.

CASE 3:

By using simulink model of CVT consists of step time, generic engine, motion sensors, vehicle transmission, vehicle body,tyres and solver configuration blocks etc., as shown in figure 11. The CVT subsystem includes look up table, Transmission block, input and output shaft inertia and motion sensors as shown in figure 12. The vehicle body subsystem includes vehicle body block, double drum brake and tyres as shown in figure 13. The initial engine speed is given as 2100 rpm, mechanical rotation for driven pulley and driver pulley as 0.8 & 0.7 respectively. The mass of the vehicle as 250kg and 2 axles which connects 4 wheel accordingly
A lookup table is an array of data that maps input values to output values, thereby approximating a mathematical function. Given a set of input values, a lookup operation retrieves the corresponding output values from the table. If the lookup table does not explicitly define the input values, simulink can estimate an output value using interpolation, extrapolation, or rounding, where

• An interpolation is a process for estimating values that lie between known data points
• An extrapolation is a process for estimating values that lie beyond the range of known data points
• A rounding is a process for approximating a value by altering its digits according to a known rule

CASE 4:

The above figure shows 'Baja ATV with dashboard' model using lookup table which consists throttle meter and brake input in the dash board and indicated as constant block. Rest of the blocks and subsystems are common in the above Baja ATV model without dash board as shown in figure 12 & figure 13. The main concept of using dash board is study the result by varying the input of brake and throttle, which shows that the variation of velocity and speed of the engine. The gear ratio is given by lookup table, simulink get the input value from the lookup table and obtain the result according to the lookup table. As the brake input varies from 0 - 0.5, the velocity and speed decreases accordingly which inturn the gear ratio also decreasing. By increasing the throttle, the velocity and speed of the engine & shaft increases. The transmission as primary pulley and secondary pulley, in which the radius of primary pulley incresed by compacting and the radius of secondary pulley decreases. As the gear ratio varies, the torque also varies. Gear ratio is directly proportional to the torque, which increases by increasing the gear ratio. At the max torque, the speed and velocity is decreases.

CONCLUSION:

we have successfully analysed 4 different models of BAJA ATV WITH CVT and recorded the outputs (Vehicle velocity & CVT shaft rpm) with respect to variations in input throttle and brake.