Electromagnetic Tracker for Active Handheld Robotic Systems.

We describe the development of the In-Loop Electromagnetic Tracker (ILEMT), designed to meet the demanding latency and resolution requirements for active stabilization of hand motion during precision manipulations such as microsurgery. The prototype surpasses the fastest commercial EM trackers by > 4× in root bandwidth/resolution and 2× in latency. The use of two widely spaced carrier frequencies (e.g., 300 Hz and 10 kHz) enables a particularly simple way of reducing the eddy-current interference caused by nonferrous metals present in the workspace. Previously, metal compatibility has only been achieved at a large cost to measurement speed.