Methods for locating and sensing the position, orientation, and contour of a work object in a robotic system

A method of locating a position and at least one additional feature of an object surface using at least one distance sensor positioned by a robot of a robotic system, the method comprising the steps of:

• a) the robotic system iteratively translating the distance sensor of the robotic system along a sensor measurement axis of the distance sensor across a range of motion of the distance sensor along the sensor measurement axis and incrementally moving the distance sensor, until the object surface lies along the sensor measurement axis, and within a measurement range, of the distance sensor for the robotic system in a first position;
• b) the robotic system obtaining a first distance measurement between the distance sensor and a first point on the object surface with the robotic system in the first position and storing the first distance measurement in a repository;
• c) the robotic system collecting a plurality of first robot positional data for the robotic system in the first position from a robot position-determining mechanism of the robotic system and storing the first robot positional data in the repository;
• d) the robotic system computing a first location in three-dimensional Cartesian space for the first point on the object surface by using the first distance measurement and the first robot positional data;
• e) the robotic system incrementally adjusting the distance sensor to a plurality of additional positions along a path, the robotic system repeating steps b) through d) for each additional position;
• f) the robotic system plotting the additional positions as Cartesian Z-axis values along the path;
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• g) the robotic system analyzing the Cartesian Z-axis values to locate any inflection points, maxima, minima, and discontinuities as additional features of the object surface.

A method of verifying an accuracy of a distance sensor controlled by a robot in a robotic system, the method comprising the steps of:

• a) the robotic system locating a test surface using the distance sensor;
• b) the robotic system moving the distance sensor along a measurement axis of the distance sensor, until the test surface lies along the sensor measurement axis, and within a measurement range, of the distance sensor for the robotic system in a first position;
• c) the robotic system measuring a first distance to the test surface using the distance sensor with the distance sensor at the first position and collecting a plurality of first robot positional data for the distance sensor in the first position from a robot position-determining mechanism of the robotic system and storing the first distance and the first robot positional data in a repository;
• d) the robotic system repeating steps b) and c) for a plurality of additional positions within the measurement range of the distance sensor;
• and
• e) the robotic system comparing a measured change in distances by the distance sensor between at least one pair of the positions of the distance sensor and a calculated change in distances based on the positional data for the at least one pair of the positions to determine whether a difference between the measured change and the calculated change is within a predetermined tolerance for the distance sensor.

A method of verifying an accuracy of a plurality of distance sensors controlled by a robot in a robotic system, the method comprising the steps of:

• a) the robotic system moving a first distance sensor of the plurality of distance sensors along a measurement axis of the first distance sensor, until the test surface lies along the sensor measurement axis, and within a measurement range, of the first distance sensor in a first position;
• b) the robotic system obtaining a first distance measurement between the first distance sensor and test surface and collecting a plurality of first robot positional data for the first distance sensor in the first position from a robot position-determining mechanism of the robotic system and storing the first distance and the first robot positional data in a repository;
• c) the robotic system sequentially moving each additional distance sensor of the plurality of distance sensors to the first position using the first robot positional data and measuring additional distances to the test surface using each additional distance sensor with each additional distance sensor at the first position and storing the additional distance measurements in the repository;
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• d) the robotic system comparing the first distance and each additional distance to determine whether a difference between the first distance and each additional distance is within a predetermined tolerance for the plurality of distance sensors.

A method of autonomously calibrating a plurality of distance sensors controlled by a robot in a robotic system, the method comprising the substeps of:

• a) the robotic system sequentially moving each of the plurality of distance sensors to a previously-programmed first reference position lying in front of a fixed reference surface;
• b) the robotic system sequentially activating a first distance sensor calibration signal to calibrate a first distance sensor range limit for each of the plurality of distance sensors;
• c) the robotic system sequentially moving each of the plurality of distance sensors to a previously-programmed second reference position lying in front of the fixed reference surface;
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• d) the robotic system activating a second distance sensor calibration signal to calibrate a second distance sensor range limit for each of the plurality of distance sensors.

A method of autonomously compensating for an out-of-calibration or failed distance sensor in a robotic system comprising an out-of-calibration or failed distance sensor and a functioning distance sensor, the method comprising the substeps of:

• a) the robotic system substituting the functioning distance sensor for the out-of-calibration or failed distance sensor by moving the functioning distance sensor to occupy measurement positions that would have been occupied by the out-of-calibration or failed distance sensor;
• b) the robotic system obtaining distance measurements from the functioning distance sensor and storing the distance measurements in a repository;
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• c) the robotic system utilizing the distance measurements from the functioning distance sensor in place of other measurements that would have been obtained from the out-of-calibration or failed distance sensor.