Project

AIM: To describe the model properties and comment on the results.

Solution:

Model Components Description:

1. Brake and Throttle input: It is generated via the signal builder block configuration, and has given the input of constant throttle input as 0.5 which signifies the constant paddle position, while 0 for brake input.
2. Generic Engine: Has given the initial speed of the engine as 1750 RPM, and inertia of 0.008 kgm^2.
3. Engine Sensor: It senses the generic engine crankshaft rotational component.
4. CVT Ratio: It is generated via signal builder configuration. Initially, the ratio has been set to 3.7 @ t=0 seconds, again it dropped to 3.65 and revert back to 3.7 and kept constant up to 0.15 seconds, then decreased exponentially asymptotic about 6 seconds
5. CVT: Takes input as CVT Ratio and Engine rotational speed. Consist of components as an I/O shaft coupled with an I/O rotational sensor which gives the primary and secondary RPM, it also consists of a variable gear ratio with transmission stiffness of 1000 Nm/rad and transmission damping of 10 Nm/(rad/s)
6. Simple Gear: Have a constant gear ratio of 10
7. Vehicle Body: Takes input from the simple gearbox and brake input, and gives output as vehicle speed and displacement. It consists of different components such as, the left and right front tyre having a rolling radius of 267mm, and the left and right rear tire having a rolling radius of 292.1mm. It also consists of a double shoe brake of a drum radius of 150mm and shoe span angle of 120 degrees, it takes input as brake input of 1000 as a gain.
8. Vehicle Body: Consist of a mass of 250kg. CG distance from the front and rear axle are 1000mm and 350mm respectively, and CG above ground is considered 700mm. It also has a drag coefficient of 1.92 and a frontal area of 0.735482 m^2. It takes input as tyre translation movement and gives output in the form of normal force on the rear and front axle, wind velocity (Impact), vehicle velocity (further integration gives distance, and inclination angle.

Result:

1. Plots description of vehicle velocity, distance, throttle and brake input:

• Velocity: Increases parabolically till 40 seconds and then attain a constant velocity of 53km/hr
• Distance: Increases cubically till 40 seconds covering a distance of 957.764m then increases linearly to 2800m by the end of 200 seconds.
• Throttle is kept constant to 0.5 for the whole 200 seconds.
• Brake input is kept constant to zero for the whole 200 seconds.

2. Plot description of primary and secondary CVT RPM:

• Primary CVT RPM: Increases from 1750 RPM to 2050 RPM in 0.41 second, then there is a sudden dip to 1700 RPM due to variable CVT ratio and inertia, then it keeps on increasing and flattened around t=60 second at a value of 3410 RPM till the end @ t=200 second
• Secondary CVT RPM: Increases from 0 to 800 RPM in 1.35 seconds, then there is a sudden dip and rise due to variable CVT ratio and inertia and gets flattened after 60 seconds to 4870 RPM.

3. Plot description of Engine Torque V/S Speed Curve:

The plot is basically a variation of torque with engine RPM. Initially around 1500 RPM, the torque is noted as 15.5 Nm and further attain a value of 19.5 Nm @ 1800 RPM and attain a peak value of 20.57 Nm @ 2992 RPM. Afterwards, if falls down to 7.81 Nm @ 3840 RPM.