# US 4,474,047 A · Method and apparatus for inherent rotary joint calibration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,474,047 A - Document ID: US4474047A - Status: Granted - Kind: A - Application number: 06/355,286 - Filed: 1982-03-05 - Granted: 1984-10-02 - Earliest claimed: 1982-03-05 - Assignees: Texas Instruments Incorporated - Inventors: Donald E. Carlson - Web page: https://patentgrep.com/patent/US4474047A ## CPC - B25J 9/1692: {Calibration of manipulator} - G01B 7/30: for measuring angles or tapers; for testing the alignment of axes - G05B 2219/39046: Compare image of plate on robot with reference, move till coincidence, camera - B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50}) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract A manipulator having at least two segments, rotatable with respect to each other, measures the angle formed therebetween and is self calibrating to insure the accuracy of the measurement. An electrical resolver is employed, with its rotor attached to one of the segments and stator attached to the other, with the rotor and stator slotted, in registration, at a relative position indicating electrical zero. Each segment has a pin formed on it positioned to engage the slots in the rotor and stator at a mechanical zero degrees output, insuring a zero degrees mechanical output for zero volts electrical output. ## Claims ### Claim 1 A manipulator having at least first and second segments connected to measurably rotate with respect to each other, and a calibration mechanism for calibrating the measuring apparatus, comprising: (a) electrical sensing means having a rotor attached to the first segment and a stator attached to the second segment and having mechanical alignment means formed in the rotor and the stator, and in registration therebetween, corresponding to the predetermined electrical output; (b) electrical sensing engagement means having rotor locking means formed on the first segment, positioned to engage the rotor alignment means at a desired rotational position; and (c) electrical sensing engagement means having stator locking means formed on the second segment, positioned to mechanically engage the stator alignment means at the desired rotational position. ### Claim 2 (depends on 1) The manipulator of claim 1 wherein mechanical alignment means comprises slots, in registration, formed in the rotor and in the stator, wherein the rotor locking means comprises a pin formed on the first segment and wherein the stator locking means comprises a pin formed on the second segment. ### Claim 3 (depends on 1) The manipulator of claim 1 wherein the electrical sensing means comprises a resolver. ### Claim 4 (depends on 3) The manipulator of claim 3 wherein the electrical sensing means comprises a resolver. ### Claim 5 (depends on 1, 2, 3, 4) The manipulator of claims 2, 3, 4 or 1 wherein the predetermined electrical output is zero volts and the desired rotational position is zero degrees. ### Claim 6 A calibration mechanism for calibrating the apparatus for sensing the position between a first and a second segment that rotate with respect to each other, comprising: (a) electrical sensing means having a rotor attached to the first segment and a stator attached to the second segment to permit rotary motion between the rotor and the stator, and having mechanical alignment means formed in the rotor and in the stator, and in registration therebetween, corresponding to a predetermined electrical output; (b) rotor locking means formed on the first segment, positioned to engage the rotor alignment means at a desired rotational position; and (c) stator locking means formed on the second segment, positioned to mechanically engage the stator alignment means at the desired rotational position, thereby fixing the predetermined electrical output with the desired rotational position. ### Claim 7 (depends on 6) The mechanism of claim 6 wherein the mechanical alignment means comprises slots, in registration, formed in the rotor and in the stator, wherein the rotor locking means comprises a pin formed on the first segment and wherein the stator locking means comprises a pin formed on the second segment. ### Claim 8 (depends on 7) The mechanism of claim 7 wherein the electrical sensing means comprises a resolver. ### Claim 9 (depends on 8) The mechanism of claim 8 wherein the electrical sensing means comprises a resolver. ### Claim 10 (depends on 6, 7, 8, 9) The mechanism of claims 6, 7, 8 or 9 wherein the predetermined electrical output is zero volts and the desired rotational position is zero degrees.