Re: Cornering velocity bug fix

Hi David

You might looking for adjusting the inertia of the car, the cg hight, 
roll centers and the tire properties. I created a video regarding this 
some time ago, maybe you already know it:
http://youtu.be/H75kZ37j9o4

Kind regards

Bernhard

On 01/01/2015 10:06 PM, David Savinkoff wrote:
> Hi Bernhard,
>
> After seeing your explanation, I agree with you. However
> I do have some opinions.
>
> I submitted the patch because, at first glance, it looked
> like x and y may have been swapped... and the car
> actually drives better (especially drifting, and dirt tracks).
>
> I attempted to make sense of my patch. Here are some
> possibilities:
>
> * Swapping the x and y axis may subtract some rotation from
> car and make it more driveable ( what a hack!).
>
> * I changed the code to the following, and the car still
> drives OK.
> car->corner[i].vel.ax = 0.0;   //- car->DynGC.vel.az * y;
> car->corner[i].vel.ay = 0.0;   //car->DynGC.vel.az * x;
>
> When I drift torcs, it feels like too much energy goes into
> rotating the car, and not enough into going forward. As if
> the bumper is plowing the ground. I actually had an old
> Cadillac that would plow the sawdust I drove in. When the
> pile got over the bumper, the car would simply dig in
> (it could not rotate).
>
> If you could point me to the right part of torcs, maybe I'll
> find what I'm looking for. Thanks.
>
> Sincerely,
> David Savinkoff
>
> ----- Bernhard Wymann wrote:
>> Hi David
>>
>> I reviewed the suggested change, but I think it is wrong (I think the
>> original code is right).
>>
>> Simply assume a "1-d car" (a simple line from top), with one corner at
>> (x,y) as (1,0) and an angular velocity around the z-Axis := vz.
>>
>> So the speed of the corner relative to the rotation center is in y
>> direction r*vz, where r=x=1. I cannot see a flaw in this.
>>
>> With your change you would get a movement in x direction although the
>> radius in y direction is 0, that does not make any sense to me.
>>
>> Other thoughts, other opinions?
>>
>> Kind regards
>>
>> Bernhard
>>
>>
>> On 12/18/2014 02:31 AM, David Savinkoff wrote:
>>> Hi,
>>>
>>> TORCS was fueling my high velocity entertainment when road rage set in
>>> and I had to glare at the source code to calm down.
>>>
>>> I think I found a bug.
>>>
>>> The car drives much better now.
>>>
>>> Sincerely,
>>> David Savinkoff
>>>
>>>
>>>
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>
>


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