Car Dynamics
This page will stand as an overview of the dynamics modelling of the Midnight Sun XV car.
The physics of the system is the same as from the car dynamics for MSIV for now.
Physics of System
Midnight Sun can be, at a high level, seen as a vehicle with five forces acting upon it. The force of aerodynamic drag, friction, braking, motors and gravity. Since braking is intentional and no energy is expended in the change of state, it will not be considered for the system (the implementation of regenerative braking not being covered by this topic paper).
This means we can rewrite the state of the car at any given instance as Fmotor + ma = Ffric + Fdrag + Fg
, where each of the forces are defined by the following equations
Ffric = Fn * Crr
Fn = m * g * cos(theta)
Fdrag = 1/2 * rho * CdA * v^2
Fg = m * g * sin(theta)
Finally we get our equation, where m is the mass of cass, g is the acceleration of gravity, v is the vehicle velocity, vwind is the velocity of the wind, Crr is the coefficient of rolling resistance, CdA is the combined drag coefficient (essentially a fudge coefficient to relate the force experienced by the vehicle to its velocity squared), rho is the density of air, and theta is the angle between the ground and the car.Fmotor = m * g * cos(theta) * Crr + 1/2 * rho * CdA * (v+vwind)^2 + m * g * sin(theta)
+ ma
With this equation, we can calculate the force requirement for any velocity and acceleration pair, which can then be integrated over time to get the energy requirement of the vehicle.
Inputs of System
Takes a series of velocities and elevations measured over (a variable) distance - which can take input from the RouteElevation/CoordinateElevation.
Outputs of System
The amount of energy consumed by the car over the velocities/elevations.
To do so, the force required at each point is computed, which can be explored.