Fast and high-precision 3D tracking and position measurement with MEMS micromirrors

A method for optically locating and tracking an object in three dimensions and measuring a position in three dimensions, comprising:

• a) scanning a first reflector about a first axis and a second axis;
• b) scanning a second reflector about a third axis and a fourth axis;
• c) generating radiation with one or more optical sources;
• d) reflecting the radiation with the first and second reflectors while scanning the first and second reflectors;
• e) using one or more optical detectors to determine when the first and second reflectors provide first and second optical paths between the one or more optical sources and the one or more optical detectors, wherein the optical path originates or terminates at the object;
• f) determining values of the first and second angles of rotation of the first reflector with respect to the first and second axes at a time when the first reflector provides the first optical path;
• g) determining values of the third and fourth angles of rotation of the second reflector with respect to the third and fourth axes at a time when the second reflector provides the second optical path;
• and
• h) determining a position of the object in three dimensions from the values of the first, second, third and fourth angles.

A system for optically locating and tracking an object, comprising:

• an optical source configured to generate an optical beam;
• an optical scanner having a reflector mounted to a two-dimensional actuator configured to control a tilt of the reflector about a first axis and a second axis, wherein the scanner is configured to deflect the optical beam toward an object;
• and optical detector responsive to radiation from the optical source deflected by the object;
• and
• a controller coupled to the optical detector and the optical scanner,
• wherein the object has retro-reflective properties such that when the reflector is aligned to provide an optical path between the optical source and the object, the object reflects a portion of the radiation in the general direction of the reflector;
• wherein the detector is configured such that it does not obscure an optical path between the reflector and the object and wherein the detector is configured to receive a portion of the radiation that is reflected by the object in the general direction of the reflector;
• wherein the controller is configured to determine from one or more detection signals from the optical detector whether the reflector is aligned to provide an optical path between the optical source and the optical detector, wherein the detector is configured such that the optical path from the source to the detector does not intersect the reflector along a return portion of the optical path from the object to the detector;
• and
• wherein the controller is configured to determine a position of the object from control signals to the two-dimensional actuator of the optical scanner obtained when the reflector is aligned to provide the optical path between the one or more optical sources and the one or more optical detectors,
• wherein the control signals determine a tilt of each reflector about its first and second axes.

A method for optically locating and tracking an object, comprising:

• a) scanning a reflector about a first axis and a second axis;
• b) generating radiation with an optical source;
• c) reflecting the radiation with the reflector while scanning the reflector;
• d) using an optical detector to determine when the reflector provides an optical path between the optical source and the optical detector, wherein the optical path is deflected at the object, wherein the object has retro-reflective properties such that when the reflector is aligned to provide an optical path between the optical source and the object, the object reflects a portion of the radiation in the general direction of the reflector,
• wherein the detector is configured such that it does not obscure an optical path between the reflector and the object and wherein the detector is configured to receive a portion of the radiation that is reflected by the object in the general direction of the reflector, and wherein the optical detector is configured such that the optical path from the source to the optical detector does not intersect the reflector along a return portion of the optical path from the object to the detector;
• f) determining values of the first and second angles of rotation of the reflector with respect to the first and second axes at a time when the reflector provides the optical path;
• h) determining a position of the object from the values of the first and second angles.