### Physics model

Team Popcorn

Hi guys,

As I've said I am working on a physics model, but I wanna make sure it does what you expect it to do.

*It should have one main input :

The initial speed of the agent or the initial power output of the engine.

* Using the above input physics model which willl take into account the other factors like the friction will calculate and return the theoretical speed of the agent.

* I would try to make the model more advance so it will give out vectors, so the agent will have some sense of direction as well.

Anyhow, I am away until Sunday, could you guys please make comments so I know if I am on the right track.

Cheers !

Anushka

## 2 Comments:

Anushka,

That's pretty much correct. Use F=ma for finding acceleration. m is mass set by the user and F is the power output for the car as a whole.

This relies on the geometric calculations. You have to find the throttle setting for each wheel. Say it's 0.8 out of a maximum of 1.0. Using F=ma we can find the acceleration the agent /wants/ to acheive.

Using F=ma again but with the force this time provided by the friction between the ground and the wheels, we can see if the desired acceleration for the car is greater than should be allowed, and if so, we skid.

Finding the acceleration of the car as a whole isn't straightforward, as we have two drive wheels to consider. We could have maximum acceleration for each wheel in opposite directions and the car would spin on its central point. But with the wheels turning at different rates in either direction you have to use the geometry from the notes I printed out (I also sent a link to the mailing list) to find the overall acceleration of the car.

Don't forget that each wheel as an individual can skid, so if one wheel is accelerating slightly too hard and the other is within the limits, then only the wheel which is going too hard will skid.

It's all quite involved and I reckon it'll take at least 2 of us to get the physics model going anywhere.

By Mark Rowan, at 31 January 2005 at 00:47

By the way there's no reason to limit the physics model to one input. It should be taking everything possible into account: acceleration, mass, power of engine, current slipping speed, etc.

I recommend we base a lot of the model on what's described at http://rars.sourceforge.net/doc/co_vecto.htm

By Mark Rowan, at 31 January 2005 at 00:52

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