Dexterous control, Intelligent is key to the success of any programmable robot, whether it is an arm, automatically guided vehicle, or dexterous hand. While robotic intelligence is generally associated with processor-driven motor control, many biological systems, including human hands, integrate some degree of specialized reflex control independent of explicit motor-control signals from the brain. Actually, the BarrettHand combines programmable microprocessor intelligence and reflexive mechanical intelligence for a high degree of practical dexterity in real-world applications.
Base on the definition, neither the BarrettHand nor your hand is dexterous. Basically, their superior versatility challenges the definition itself. If the BarrettHand is followed by the strict definition for dexterity, it would require between eight and 16 motors, making it far too complex, bulky, and unreliable for any practical application outside the mathematical analysis of hand dexterity. But, by exploiting four intelligent, joint coupling mechanisms, the almost-dexterous BarrettHand needs only four servomotors. In some examples reflex control is even better than deliberate control. Two examples based on your own body illustrate this point. Accidentally suppose your hand touches a dangerously hot surface. It starts retracting itself instantly, relying on local reflex to override any ongoing cognitive commands. Your hand might burn when waiting for the sensations of pain to travel from your hand to your brain via relatively slow nerve fibers and then for your brain, through the same slow nerve fibers, to command your arm, wrist, and finger muscles to retract.
As the second example, let’s move the outer joint of your index finger without moving the adjacent joint on the same finger. You cannot shift these joints independently because the design of your hand is optimized for grasping. Your tendons and muscles are as lightweight and streamlined as possible without forfeiting functionality. The BarrettHand design recognizes that intelligent control of functional dexterity requires the integration of microprocessor and mechanical intelligence.
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