Laser gauge for robotic calibration and monitoring
A contactless, and accurate device and methods of use thereof are provided to calibrate and verify the calibration of a robotic arm and associated attachments. The device uses a laser gauge for calibrating and subsequently verifying the calibration of the robotic arm, digitizer, or robotic tools. An optical transmitter, in communication with an optical receiver is fixed nearly perpendicular to a second optical transmitter in communication with a second optical receiver that form two optical micrometers that are offset a small distance, forming a small gap, d, to create a measuring void having two distinct non-intersecting measurement planes. One measurement plane measures the position and size of an object in a first axis direction and the other measurement plane measures the position and size of an object in a second axis direction. The position and size of an object is measured within the measuring void in both axial directions.
1. An optical gauge for calibration of a robotic arm or a tool attached thereto, said optical gauge comprising:
a first optical transmitter in communication with a first optical receiver to form a first optical micrometer defining a first direction of planar measurement;
a second optical transmitter in communication with a second optical receiver to form a second optical micrometer defining a second direction of planar measurement nearly perpendicular to the first direction, said first optical micrometer being offset in a fixed position from said second optical micrometer by a known gap distance in a third direction orthogonal to the first direction and the second direction to create a measurement void with the first direction of planar measurement and the second direction of planar measurement in a space defined between said first optical transmitter and said first optical receiver and between said second optical transmitter and said second optical receiver to obtain calibration data as to position or size of the robotic arm or a tool attached thereto when positioned within or passed through the measurement void; and
a processor configured to calibrate or verify the calibration of a robot with the calibration data.
2. The optical gauge of claim 1 wherein the first direction of planar measurement is a first plane that measures a first position or a first size of an object in a ‘y’ axis direction and the second direction of planar measurement is a second plane that measures a second position or a second size of the object in a ‘x’ axis direction; and wherein a third position or a third size of the object is measured within the measuring void in a ‘z’ axis direction.
3. The optical gauge of claim 1 wherein said first optical receiver and said second optical receiver are detection devices comprising at least one of photodiodes, CCD cameras, CMOS cameras, magnetic field sensor, or transducers.
4. The optical gauge of claim 1 further comprising a casing to house said first micrometer and said second micrometer for attachment to a robot, where a set of coordinates of said measuring void is known with respect to the robot coordinates.
5. The optical gauge of claim 1 further comprising at least one amplifier connected to at least one of said first micrometer and said second micrometer in communication with a robot.
6. The optical gauge of claim 5 wherein said robot is configured as an autonomous or semi-autonomous robotic system either for medical or industrial applications.
7. The optical gauge of claim 5 wherein said processor or a robot computer performs mathematical operations to obtain a set of additional information about the orientation, velocity, or acceleration of a robotic arm or a tool attached thereto when positioned within or passed through the measurement void.
8. A method for verifying calibration of a robotic arm with the optical gauge of claim 1 comprising:
performing an initial calibration of said robotic arm;
passing an end effector of said robotic arm through said measurement void at least once;
recording and storing from said first micrometer and said second micrometer a position of said end effector within said measuring void; and
using the recorded position of said end effector from said initial calibration procedure as a comparison tool to verify the robotic arm calibration in a subsequent calibration procedure.
9. A method for verifying calibration of a robotic arm with the optical gauge of claim 1 comprising:
performing an initial calibration of said robotic arm;
passing said end effector of said robotic arm through said measurement void three times to obtain three measured positions of said end effector;
calculating and storing a set of side lengths and a set of angles between the three measured positions in three dimensional space; and
using the stored set of side lengths and the set of angles from said initial calibration procedure as a comparison tool to verify the robotic arm calibration in a subsequent calibration procedure.