- Robert A. MacLachlan, Brian C. Becker and Cameron N. Riviere
The Robotics Institute
Carnegie Mellon University,
Contact: camr 'at' cs.cmu 'dot' edu, brianbec 'at' cs.cmu 'dot' edu
Control of an Active Handheld Instrument for Microsurgery and Micromanipulation
“Micron” is a fully handheld manipulator that enhances accuracy in microsurgery and micromanipulation by active compensation of the physiological hand tremor of the user. To sense the motion of the device in six degrees of freedom, a set of four LEDs is tracked by orthogonally placeds planar photodiodes. Three LEDs are affixed to the tip manipulator, and the fourth is mounted on the tool handle, which is also the base of the manipulator. The LEDs are pulsed at different rates, and a frequency-domain multiplexing scheme is used to track each light source separately with roughly 4- micron precision peak-to-peak at 1000-Hz sampling. The sensory information is used to enable feedback control of the tip manipulator, which is a 3-dof parallel mechanism driven by Thunder © piezoelectric actuators to provide accuracy enhancement in a workspace approximately 1 mm x 3 mm x 3 mm.
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