Week 7 Challenge

Vehicle Model

A vehicle model is a mathematical representation of a vehicle's behavior and dynamics, which can be used to simulate and analyze its performance under different conditions. The vehicle model typically includes a set of equations that describe the physical forces acting on the vehicle, as well as its kinematics and dynamics. These equations take into account various factors such as the vehicle's mass, aerodynamic properties, tire characteristics, and engine performance.

There are different types of vehicle models depending on their complexity and intended use. Some models are simple and focused on specific aspects of the vehicle's behavior, such as the suspension or the engine. Others are more complex and take into account multiple systems and interactions between them. Vehicle models can be used for various purposes such as design optimization, performance evaluation, control system development, and safety analysis.

Overall, a vehicle model is an essential tool for engineers and researchers to understand and improve the performance of vehicles, as well as to design and test new technologies and systems

To find the total force acting on a vehicle, you need to consider all the forces that act on the vehicle at a given time. The total force acting on the vehicle is the vector sum of all these forces, taking into account their direction and magnitude.

The forces acting on a vehicle include:

Gravity: This force is always acting on the vehicle and is equal to the product of the vehicle's mass and the acceleration due to gravity, i.e., Fg = m * g, where m is the mass of the vehicle and g is the acceleration due to gravity.

Aerodynamic drag: This force is proportional to the square of the vehicle's velocity and depends on factors such as the vehicle's shape and size, air density, and speed. The force of aerodynamic drag can be calculated using the equation Fd = 0.5 * Cd * A * rho * v^2, where Cd is the drag coefficient, A is the frontal area of the vehicle, rho is the air density, and v is the vehicle's velocity.

Rolling resistance: This force is caused by the interaction between the tires and the road surface and depends on factors such as the tire properties, road surface, and vehicle speed. The force of rolling resistance can be calculated using the equation Fr = m * g * Crr, where Crr is the rolling resistance coefficient.

Engine force: This force is generated by the vehicle's engine and is transmitted to the wheels through the transmission system. The force generated by the engine can be calculated using the equation Fe = Te * GR / r, where Te is the engine torque, GR is the gear ratio, and r is the wheel radius.

To find the total force acting on the vehicle, you can add up all these forces:

Ftotal = Fg + Fd + Fr + Fe

The total force acting on the vehicle will depend on the driving conditions, such as the vehicle speed, road surface, and engine output.

Simulink model :

It consist of driver block vehicle block only

Here thw Driver block is used to accleration purpose the value to overcome the integral windup happeneing while converting tractive force into velocity

So Hence the only vehicle block system is consider as major system block in the vehicle modeling

Subsytem of the Driver Block:

In this we created a inputs as desired velocity and actual velocity

And aslo output as Accelerator ,brake ,

We aslo used the below steps

1)Compute the error

2)Proportional control

3)Integral control reset when velocity is 0

4)Derivative controller

Vehicle model subsystem :

In this we used input as traction force and output as velocity

Working of the above designed model :

Initially we loaded the excel file into the siginal builder block as shown in below

Here The input to the vehicle block is tractive force this tractive force is teh force which is applied by the powertrain to the vehicle body

Here we have given tractive force directly as a input its values are in newton its plot the values as shown in above siginal builder block

Vehicle model subsystem:

This is the major block which lay key role in vehicle modeling

So to find velocity let us asume that all the forces acting on vehicle this force of traction which is given as

F_trac = Force of acceleration+ Rolling Resistance Foce+ Gradient Force+ Aerodynamic Force

The term force of acceleration will help us to find the velcoity we will first seperate the acceleration term and resistive force terms.

F_trac-Fr-Fg-Fd=Fa

F_trac-Fr-Fg-Fd= m*a

F_trac-Fr-Fg-Fd/m=a

So we now have to acclerate

Here The forces other than F_trac in model is calculated by formula implementation using Fcn block

So now We have taken grade is zero hence there will be no gradient force acting on vehicle

Here Fr is independent of velocity value but only acts on vehicle when its moving