I'm reading "ESL 04-10: Simulation of Vehicle Longitudinal Dynamics" in
an attempt to write a car simulations engine. However I came across
several dilemmas and was hoping to find answers here
- In page 3 an equation (04/01/C) of the form: V = (-Fxt +
g*sin(theta) - Fd(V)) / m
Was supposed to give the velocity of the car as the net force divided
by mass. However, IIRC such a formula would give the acceleration not
the velocity (A similar equation was given in page 6 for the angular
velocity)
- Another equation (04/01/D):
Fz = mg {(C/L)cos(theta) + (H/L)sin(theta)} - mV (H/L)
Is supposed to give the normal force on the front wheels. Which is a
variable controlling the total force (Fxt) in the first equation
(04/01/C). Now suppose that theta is 0 which means that the***term
would evaluate to zero, and suppose that the car is starting with zero
velocity which means that the second term is also zero. And Fz is zero
as a whole, hence Fxt is also zero (No force is acting on the vehicle
body). Since Fxt is zero this would mean that V is also zero (from the
first equation). And we are faced with a paradox: The car won't move
until a force is applied to it, but no force will be applied until the
car moves. I suppose that in real life clutching/declutching the engine
will solve this problem, however how can I solve such a problem in a
simulation?
PS: Article link: www.le.ac.uk/eg/embedded/pdf/ESL04-01.pdf
Thank you for your time
Abdo Haji-Ali
Programmer
In|Framez