Institute for Systems Research University of Maryland at College Park

Demos and Videos

Contents

• Grasping with the Modular Dextrous Hand
• Roller-Racer: Micro-controller Based Prototype
• Walking Robot

The Modular Dextrous Hand (MDH) is a general purpose robotic hand developed at the University of Maryland. The term "modular" refers to the hands design philosophy...the hand has one module (3 single degree of freedom fingers) used for grasping and a second, seperate module (a 6 degree of freedom stewart platform) used for finely manipulating the grasped object. The MDH is capable of grasping and finely manipulating objects having a wide variety of shapes and sizes. Even so, because of its modular design, the MDH is less complex and easier to control than other hands with similar functionality.

The MDH was originally concieved in 1988 and built in 1989 by J. Loncaric, F. de Comarmond, J Bartusek, Y.C. Pati, D. Tsakiris and R. Yang. Since then much work has been done by Loncaric, M.E. DeSilets and others analyzing the various configurations of the grasping module and devising grasping strategies. Currently, these grasping strategies are being implemented and tested using the ISL's new rapid prototyping test bed. Future work includes developing and employing improved grasping strategies as well implementing the stewart platform module.

This MPEG movie shows the MDH employing a simple open loop grasping stragegy to grasp a Coke bottle.

The roller racer is an example of a 2 node SE(2) snake. The kinematics, dynamics and control of such nonholonomic systems are currently being studied by Prof. P.S. Krishnaprasad and Dimitris P. Tsakiris. The prototype was designed by Vikram Manikonda.

Size of prototype: 12 x 9 x 6 in. (approx.)

Motor:
Superior Electric Co. Synchronous/Stepping Motor
Model # MA61FS-62019
Specs. Rated 10V DC. .5 amps/phase, 60 oz-in holding torque,
(approx. 30 oz-in running torque), resistance 20 ohm/phase.
Resolution : 1.8 deg/step ( 200 steps/rev ) in full step mode,
.9 deg/step ( 400 steps/rev ) in half step mode

Batteries: Two Duratrax 7.2 V rechargable

On Board Microcontroller:
On board microcontroller based on the FAUX STAMP kit from SDRFT.
Uses PIC16C56_XT/P-PBASIC 1.4 microcontroller, programmed with PBASIC interpreter through an IBM PC parallel port.

Click here to see an mpeg video of the roller racer.