DexHand - Dextrous Robotic Hand

Author: Andreas Maryanto?

DexHand - Dextrous Robotic Hand is a Robotic Hand with Five Fingers and has 11 DOF. Driven by RC standard servos. Dextrous Robotic Hand controlled by potentiometers as sensor equipped Master Glove to indicate the user’s fingers positions. A large variety of different objects can be grasped reliably and the movements of the hand appear to be very natural like human hand movements.

Hand Design

The dimensions of the fingers are close to that of a human one. Each joint has a range of rotation which equivalent to that of a human hand. Each finger joint use steel wire to drive the fingers for grasp and use a tension spring for go back to normal position.

Each finger have 2 DOF that is MP (Metacarpal Phalangeal) joint and PIP (Proximal Inter Phalangeal)joint. The DIP (Distal Inter Phalangeal) joint is passively driven follow PIP joint.

Each Finger is actuated through 2 steel wire and driven by 2 RC Standard Servos. First steel wire driving the MP joint and other steel wire for PIP and DIP joint. The RC servo have output torque of about 3.7 KgCm (51 OzIn) at 6.0 Volt.

Control

The method of control is use a power glove outfitted with potentiometers as sensor across the dorsal surface of the fingers and thumb.

Every Sensor control every DOF. The Dextrous Hand have 11 DOF, so we need 11 Sensor too. Each sensor placed at hand dorsal and thumb joints and a sensor between index finger and thumb.

As you can see in the image on the left side, each sensor on a finger connected by 2 pieces of modification telescopic antenna.

Electronics

The brain of Dextrous Hand is Microcontroller AT89S52. Sensors on power glove will give analog input to ADC 0816 and Microcontroller AT89S52 will take the digital output from ADC0816 and will be process it. Microcontroller output is Pulse and use to drive RC Servos based on ADC datas.