[ODE] Adding a good "feel" to a haptics device

[Manohar B.S]

/*--- Tatu Lahtela <lahtela at cs.tut.fi> wrote:
   I have a 6 degree of freedom haptics device and I'm
   trying to add a good
  "feel" to the objects.
*/

Hi,
   I had to do the same thing some time back. I have a
3Dof Haptic device (6Dof position). I did this way:

 1. Your Haptic device position be HIP[x,y,z].
 2. Consider a small sphere S. add it to ODE space. S
should have both mass and geom. 
 3. Now connect HIP and S with a tough Spring-Damper.
 4. Return the spring-damper forces back to the haptic
device. and apply opposite force to the Sphere using
 dBodyAddFoce(..).

 5. That's all... There are other methods in which you
can use the BallJoint constraints.

 6. You can take care of Torques also if you have 3Dof
Torque output.

 6. Never set the position of the S. It will harm the
user.

 Incase you have PHANToM let me know.

 Good Luck.
Manohar
INDIA


> Hi!
> 
> I have a 6 degree of freedom haptics device and I'm
> trying to add a good
> "feel" to the objects. The goal is that I could
> - Feel the surface of the objects with the device
> - Push them around in the scene
> - Grab and carry the objects with the device.
> 
> What I've come up so far is to create only geoms for
> the haptic device
> and update the geoms' position according to its
> movement. The positions
> updates ok and I can push other objects with these
> geoms.
> 	 But the problem is the force interaction. The
> solution I came up with
> was to send a force relative to the penetration
> depth and the normal
> vector, but this approach works ok only when
> interacting with the floor.
> It's too easy to get "too deep" in to the object and
> it either gives too
> big a force to the device or shoots the object far
> away. Especially
> touching objects directly from above is troublesome
> if the object is
> lying on the ground.
> 
> Any good suggestions how to do better force
> interaction between the two
> systems?
> 
> 
> -- 
> Tatu Lahtela <lahtela at cs.tut.fi>
> 
> _______________________________________________
> ODE mailing list
> ODE at q12.org
> http://q12.org/mailman/listinfo/ode


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