Some robotic grippers I have designed / worked on:

A. Spiers, S. Baillie, T. Pipe, and R. Persad, “Experimentally Driven Design of a Palpating Gripper with Minimally Invasive Surgery Considerations,” IEEE Haptics Symposium, pp. 261-66, 2012

R.R. Ma, A. Spiers, and A.M. Dollar
“M2 Gripper: Extending the Dexterity of a Simple, Underactuated Gripper,” In Review.

More information on the second design (and open source building instructions) may be found on the Yale OpenHand project page.