Vamos Automotive Simulator git

In Vamos, a car is modeled as a rigid body that consists of point masses at
fixed relative positions.  The total mass, the location of the center of mass,
and the inertia tensor are calculated from these masses.  All forces and torques
on the body are exerted by the point masses.  When the model is propagated
forward in time, the linear and angular acceleration are calculated from the
these forces and torques and the mass distribution.

A point mass may be of any type derived from the class 'Particle'.
- Particle: Has mass and weight
  - Contact_Point: Can collide with other objects
    - Wheel: Provides force and torque from tire friction and the reaction
      torque from braking.
  - Drag: Provides aerodynamic drag
    - Wing: Provides aerodynamic downforce
  - Engine: Provides reaction torque from engine rotation
  - Fuel_Tank: Mass decreases as fuel is used
  - Suspension: Provides forces from springs, dampers, and anti-roll bars

The car is controlled by setting the throttle, brake, clutch, gear, and
steering. 

The 'Engine' object determines how much torque is applied to the driven wheels
based on its rotational velocity and the current throttle setting.  The torque
curve can be defined by spline interpolation through specified points, or by the
3rd-order polynomial given in Genta's book.

Tire friction is calculated from the Pacejka function, or "magic equation".
Longitudinal and transverse components are coupled to limit the total frictional
force. 

An instance of the class 'World' mediates the interaction of a car with its
environment.  It provides 
1. the acceleration due to gravity for calculating weight
2. the atmospheric density, and velocity for calculating wind resistance and
   downforce 
3. information about contact with the track and walls
4. information about contact with other cars

The usual situation where the car is in contact with the road is handled as a
collision between the wheel and the track.  The suspension forces are calculated
from information about this collision.