8:00 – 11:00 SR

• Backups
• Some more back and forth with Brandon W. Not sure where that’s going.
• Showed Pat VISIBILITY. She might be able to help with a proof-of-concept ROI visualization
• Poked at Dong’s dynamic panel problem

11:00 – 4:00 FP

• Added force interaction between gripper and target sphere
• Determined how to make the ratio calculation work. If the sum of all of the magnitudes on the target is greater than zero, then the ratio equals the magnitude of the sum of the force vectors divided by the sum of each magnitude. A value of 1.0 means that there is no contact. A value of 0.0 is a perfectly opposing contact. As currently implemented, if the ratio is less than 0.5, then the position of the target sphere is set to the point that lies between the two grippers, otherwise the (summed) contact force vector is applied to the target.
• Need to add walls around the work environment so that the targets can’t get out of reach.
• Need to add the metal standoffs for the speakers. I was thinking about ordering some box tubing, but the sizes weren’t optimal. I’ll bend up some metal tonight.
• Need to start adding in the code that will support the experiments
  • Task code
  • Feedback options
    • Position and pressure only
    • Position, force feedback and pressure
    • Position, pressure and vibration
    • Position, force feedback, pressure and vibration.

8:00 – 10:00 SR

• Backups
• Desk issues
• Looks like someone might be interested in Visibility pretty much out of the blue. We’ll see

10:00 – 5:00 FP

• Wired up the speakers to the old grip interface. Amp and speakers work nicely
• Now to work on the force moving the gripper.
• I also need to get the target force vector back so that I know how to move the target. Not looking forward to implementing friction…
• Hmm. Before I commit to doing it right, I’m wondering if I can look at the summed magnitude of the force vectors vs the magnitude of the summed force vectors. If the first is high and the second is low, then it means that the ball is being squeezed. Above a certain ratio, The target could simply be at the center of the sensor points.
• Assuming that the above will work, I need to do the following to targets
  • An awareness of a “floor” that provides either a limit to motion or an upward force once penetrated
  • An awareness of the forces being applied and the sources of the forces. Since these are spheres with given radius, the information to be tracked could be as simple as the center positions of the items
  • Gravity and mass?

8:00 – 10:00 SR

• Backups
• Deployed new FA, which seems to be working well
• Met Pat.

10:00 – 5:00 FP

• Building a two-fingered gripper
• Going to add sound class to SimpleSphere so that we know what sounds are coming from what collision. Didn’t do that’ but I’m associating the sounds by index, which is good enough for now
• Need to calculate individual forces for each sphere in the Phantom and return them. Done. To keep the oscillations at a minimum, I’m passing the offsets from the origin. That way the loop uses the device position as the basis for calculations within the haptic loop.
• Here’s the result of today’s work: 

8:00 – 11:30 SR

• Backups
• Training

11:30 – 4:00 FP

• Basically spent the whole day figuring out how the 4×4 phantom matrix equates to the rendering matrix (I would have said OpenGL, but that’s not true anymore. I am using the lovely math libraries from the OpenGL SuperBible 5th Edition, which makes it kinda look like the OGL of Yore. Initially I thought I’d just use the vector components of the rotation 3×3 from the Phantom to get the orientation of the tip, but for some reason, parts of the matrix appear inverted. So instead of using them directly, I multiply the modelviewmatrix by the phantom matrix, Amazingly, this works perfectly. To make sure that this works, I rendered a sphere at the +X, +Y and +Z axis in the local coordinate frame. Everything tracks. So now I can create my gripper class and get the positions of the end effectors from the class. And since the position is in the global coordinate frame, it kind of comes along for free,
• Here’s a picture of everything working:
• 
• Tomorrow, I’ll build the gripper class and start feeding that to the Phantom. THe issue will be to sum the force vectors from all the end effectors in a reasonable way.