[ODE] bad wheels

[Johnson, Erik USA]

Here's mine (it's a combination of all ODE-car-steering code I've ever
seen).  This works fairly well for me.  The mAckermanRatio is kind of a
hack.  There is (was?) an issue with the dParamLoStop/dParamHiStop where
you need to set them twice.

Hope this helps!


void SetSteeringControl(const float amount)
{
   //positive = turn to right
   
   dReal v0 = amount - dJointGetHinge2Angle1(mHingeJoint[0]);
   dReal v1 = amount - dJointGetHinge2Angle1(mHingeJoint[1]);

   v0 *= 10.0;
   v1 *= 10.0;

   if (amount > 0.f) v1 *= mAckermanRatio;
   else v0 *= mAckermanRatio;

   if (mSteeringEnabled)
   {
      dJointSetHinge2Param(mHingeJoint[0], dParamVel, v0);
      dJointSetHinge2Param(mHingeJoint[1], dParamVel, v1);
      dJointSetHinge2Param(mHingeJoint[0], dParamFMax, 2.0);//<max force
      dJointSetHinge2Param(mHingeJoint[1], dParamFMax, 2.0);//<max force
      dJointSetHinge2Param(mHingeJoint[0], dParamFudgeFactor, 0.5);
      dJointSetHinge2Param(mHingeJoint[1], dParamFudgeFactor, 0.5);

      dJointSetHinge2Param( mHingeJoint[0], dParamLoStop,
-35.0*SG_DEGREES_TO_RADIANS );
      dJointSetHinge2Param( mHingeJoint[0], dParamHiStop,
35.0*SG_DEGREES_TO_RADIANS );
      dJointSetHinge2Param( mHingeJoint[0], dParamLoStop,
-35.0*SG_DEGREES_TO_RADIANS );
      dJointSetHinge2Param( mHingeJoint[0], dParamHiStop,
35.0*SG_DEGREES_TO_RADIANS );
      dJointSetHinge2Param( mHingeJoint[1], dParamLoStop,
-35.0*SG_DEGREES_TO_RADIANS );
      dJointSetHinge2Param( mHingeJoint[1], dParamHiStop,
35.0*SG_DEGREES_TO_RADIANS );
      dJointSetHinge2Param( mHingeJoint[1], dParamLoStop,
-35.0*SG_DEGREES_TO_RADIANS );
      dJointSetHinge2Param( mHingeJoint[1], dParamHiStop,
35.0*SG_DEGREES_TO_RADIANS );
   }
   else
   {
      dJointSetHinge2Param( mHingeJoint[0], dParamLoStop, 0.0 );
      dJointSetHinge2Param( mHingeJoint[0], dParamHiStop, 0.0 );
      dJointSetHinge2Param( mHingeJoint[0], dParamLoStop, 0.0 );
      dJointSetHinge2Param( mHingeJoint[0], dParamHiStop, 0.0 );
      dJointSetHinge2Param( mHingeJoint[1], dParamLoStop, 0.0 );
      dJointSetHinge2Param( mHingeJoint[1], dParamHiStop, 0.0 );
      dJointSetHinge2Param( mHingeJoint[1], dParamLoStop, 0.0 );
      dJointSetHinge2Param( mHingeJoint[1], dParamHiStop, 0.0 );

   }
} 

> -----Original Message-----
> From: ode-bounces at q12.org [mailto:ode-bounces at q12.org] On 
> Behalf Of THD
> Sent: Thursday, February 10, 2005 1:19 PM
> To: ODE at q12.org
> Subject: [ODE] bad wheels
> 
> hello, I've got problems with my vehicle-steering in ODE
> 
> My vehicle is a box with 4 spheres as wheels 
> (hinge2-jointed), it's driving on a trimesh. My problem is 
> steering. Sometimes the left wheel locks steering full left, 
> sometimes the wheels steer in different direction, also 
> problem increases when I drive faster. 
> 
> As you see beneath I ty to solve it setting 
> dParamLoStop/dParamHiStop, but it doesn't seem to help...
> 
>  This piece of code is called every frame: 
> (m_isSteering is a bool checking if the steering keys are 
> down, m_steer is float that increases if I press the steering keys.)
> 
> 
> if(m_isSteering == false)
> {
>   m_steer = 0.0f;
>   dJointSetHinge2Param (wheel1id, dParamLoStop, 0);
>   dJointSetHinge2Param (wheel1id, dParamHiStop, 0);
>   dJointSetHinge2Param (wheel2id, dParamLoStop, 0);
>   dJointSetHinge2Param (wheel2id, dParamHiStop, 0); } else {
>   dReal v = m_steer - dJointGetHinge2Angle1(wheel1id);
>   if (v > 0.1f) 
>     v = 0.1f;
>   if (v < -0.1f) 
>     v = -0.1f;
>   v *= 10.0f; 
> 
>   dJointSetHinge2Param (wheel1id, dParamVel, v);
>   dJointSetHinge2Param (wheel1id, dParamFMax, 0.2f);
>   dJointSetHinge2Param (wheel1id, dParamLoStop, -0.5f);
>   dJointSetHinge2Param (wheel1id, dParamHiStop, 0.5f);
>   dJointSetHinge2Param (wheel1id, dParamFudgeFactor, 0.1f); 
> 
>   dJointSetHinge2Param (wheel2id, dParamVel, v);
>   dJointSetHinge2Param (wheel2id, dParamFMax, 0.2f);
>   dJointSetHinge2Param (wheel2id, dParamLoStop, -0.5f);
>   dJointSetHinge2Param (wheel2id, dParamHiStop, 0.5f);
>   dJointSetHinge2Param (wheel2id, dParamFudgeFactor, 0.1f); } 
> 
> 
> Shouldn't this work? 
> Anyone who got any better steering-"algoritm" or suggestion?
> 
> 	/Sepultang
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