Project

Aim:

Analysis of Baja all-terrain vehicle using Simulink model

Objective:

To prepare Baja all-terrain vehicle technical data technical report and explaining the model properties and comment on results.

All-terrain vehicle:

All-Terrain Vehicles (ATV) are among the most useful land vehicles ever invented. Designed to combat the hazards of different kinds of terrain, they can be used in almost every worksite there is. Not only do they make traveling easier for drivers, they are also safe to use when transporting loads or cargo.

Components of Baja all terrain vehicle

• Vechile body
• Engine
• Continuously variable transmission(CVT)
• Suspension
• Tire

Continuously variable transmission(CVT)

A CVT, or continuously variable transmission, seamlessly changes through an unending range of effective gear ratios while you drive, whereas other kinds of mechanical transmissions offer a fixed number of gear ratios and have hard shifts between each as explained by Certified Transmission Repair. CVT transmission systems are also known as single-speed, shiftless, and stepless transmissions.

The shiftless nature of a CVT offers unparalleled flexibility that maintains constant angular velocity regardless of output speed. Additionally, a continuously variable transmission makes accelerating smooth and offers enhanced fuel economy.

The main componrents of CVT;

• Primary pulley
• Secondary pulley
• Variator
• Belt

Types of baja ATV model in Simulink:

• Model without dashboard
• Model with dashboard
• Model lookup table data extraction
• Model mapped lookup table without dashboard
• Model mapped lookup table dashboard

Simulink model for baja all terrain vehicle with CVT :

Signal builder :

Signal builder is used for giving input value of brake input and throttle input and its connected with generic engine.

Where;

• Break input=0;
• Throttle input =0.3 for first 20 sec, after 20 sec throttle input

Generic engine :

Represents a system level model of spark-ignition and diesel engines suitable for use at initial stage of modelling when only the basic parameters are available. Optional idle speed and red line controllers are included.

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.

Torque vector and speed vector values are assigned in workspace.

Engine sensor:

Engine sensor is connected with generic engine. It contains ideal mechanical rotational sensor that converts an across variable measured between two mechanical rotational nodes into a control signal proportional to angular velocity or angle.

Simple gear:

Engine is connecting to CVT with simple gear ratio for speed reduction.

Cvt ratio:

Signal builder for cvt ratio block is connected by giving random ratio to get the value for those random cvt ratio.

Vehicle body:

It represents a two axle vehicle body in longitudinal motion. The block accounts for body mass, aerodynamic drag, road incline and weight distribution between axlees due to acceleration and road profile. The vehicle can have the Same or a different number of wheels on each axle. Optionally include pitch and suspension dynamics or additional variable mass and inertia. The vehicle does not move vertically relative to the ground.

Vehicle body contains two front wheels and two rear wheels which is connected with inertia output shaft and double shoe brake.

Vehicle speed plot:

CVT shaft speed plot:

Simulink model for BAJA ATV with CVT using dashboard :

In this Simulink model, RPM gauge, velocity gauge, brake input, throttle input are connected in the dashboard. Brake input is 0, throttle is 0.3 for initial condition to run the simulation.

Dashboard is connected with BAJA ATV using CVT in Simulink model and with the help of dashboard, variation of speed and velocity will display in the RPM and velocity gauge.

BAJA ATV model using lookup table

The model work flow is same as the process of BAJA ATV model without dashboard. Here the lookup table has been assigned as input to CVT instead giving CVT ratio. For giving input of look up table by creating a program in the MATLAB and data has been assigned as input to the CVT.

The results are same as without dashboard model but an additional output is the CVT ratio and vehicle velocity to the workspace

RESULTS:

BAJA ATV model mapped lookup table without dashboard:

The workflow process is same as without dashboard model, here instead of signal builder blocks for brake and throttle input.

At 35sec the brake input will take a step of value 0.

Throttle input

Instead of signal builder block for CVT ratio the 2-D lookup table is used. The interpolation and extrapolation methods are set to linear.

CVT shaft speed:

Vehicle speed:

CVT ratio:

BAJA AVT model mapped lookup table with dashboard:

Here the throttle and brake inputs are controlled by the user with knob foleewed by the vehicle speed is given as feedback to the CVT ratio lookup table.

CVT shaft speed

Vehicle speed:

CVT ratio