# US 2014/0156221 A1 · Angular position encoder for a rotating shaft > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0156221 A1 - Document ID: US20140156221A1 - Status: Published application - Kind: A1 - Application number: 13/921,580 - Filed: 2013-06-19 - Published: 2014-06-05 - Earliest claimed: 2012-06-20 - Assignees: SSB Wind Systems GmbH & Co. KG - Applicants: SSB Wind Systems GmbH & Co. KG - Inventors: Fabio BERTOLOTTI; Sebastian SBONNIK; Thomas SUMBECK - Web page: https://patentgrep.com/patent/US20140156221A1 ## CPC - G01D 5/20: by varying inductance, e.g. by a movable armature - G01B 21/22: for measuring angles or tapers; for testing the alignment of axes - G01D 5/2457: {Incremental encoders having reference marks} - G01P 3/66: using electric or magnetic means (G01P3/80 takes precedence; measuring short time intervals G04F8/00, G04F10/00) - G01P 21/02: of speedometers - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) ## Abstract An angular position encoder for a rotating shaft is disclosed, in particular for application on the rotor shaft in wind turbines. A materialized measure in the form of a roller chain is arranged around the circumference of the shaft. A scanning head in the form of a sensor is arranged at a distance from the materialized measure and scans the surface of the materialized measure as the shaft is rotating. A measurement value evaluation unit processes recorded measurement values to give positional and/or speed data on the shaft. A method for determination and measurement of the rotor speed or position for a rotating shaft by means of the angular position encoder is also disclosed which includes determination and measurement of the rotor speed or position, creating or mapping at least one reference pattern or map of the chain, and a comparing the pattern and an actual measurement value. ## Claims ### Claim 1 An angular position encoder for a rotating shaft comprising: a materialized measure arranged around the circumference of the shaft; at least one scanning head in the form of a sensor; and a measurement value evaluation unit which processes recorded measurement values such that they are evaluable or evaluated and can be or are processed to give positional and/or speed data on the shaft, wherein the scanning head is arranged at a distance from the materialized measure and the sensor signals scan the surface of the materialized measure as the shaft is rotating; wherein the materialized measure includes a roller chain with chain elements having inner rollers or pins which are aligned in the axial direction of the shaft, and wherein the chain is secured with a non-positive form-fit to the shaft circumference. ### Claim 2 (depends on 1) The angular position encoder according to claim 1, wherein a scanned surface of the inner rollers or pins during a scanning process have a sinusoidal analogue pattern. ### Claim 3 (depends on 1) The angular position encoder according to claim 1 wherein the sensor comprises an inductive analogue proximity sensor. ### Claim 4 (depends on 1) The angular position encoder according to claim 1 wherein the sensor comprises at least two analogue sensors arranged a set distance from one another. ### Claim 5 (depends on 1) The angular position encoder according to claim 1 wherein the measurement value evaluation unit further comprises a sequential program with an algorithm which from at least one sensor signal determines the position and/or speed of the shaft. ### Claim 6 (depends on 1) The angular position encoder according to claim 1 wherein the measurement value evaluation unit further comprises a memory in which saved measurement values are stored for comparison with an actually measured value, wherein the actual value is adapted to the saved value. ### Claim 7 (depends on 1) The angular position encoder according to claim 1 wherein ends of the chain are connected to one another by means of a chain connecting link that can be clamped. ### Claim 8 (depends on 1) The angular position encoder according to claim 1 further comprising a non-slip strip is arranged wherein between the chain and shaft surface as a shaft slip and vibration protector. ### Claim 9 (depends on 1) The angular position encoder according to claim 1 wherein the chain on the shaft circumference has at least one guide device. ### Claim 10 (depends on 9) The angular position encoder according to claim 9, wherein the at least one guide device has a groove on a scanning surface in which the chain is guided. ### Claim 11 (depends on 10) The angular position encoder according to claim 10, wherein the scanning surface has a curvature to match the radius of curvature of the circumference of the shaft. ### Claim 12 (depends on 9) The angular position encoder of claim 9 wherein the at least one guide device comprises a scanning head and the at least one sensor. ### Claim 13 (depends on 1) The angular position encoder according to claim 1 wherein the chain has a set synchronization point for the position determination on the shaft surface. ### Claim 14 (depends on 13) The angular position encoder according to claim 13 wherein the synchronization point is arranged in a chain connecting link. ### Claim 15 (depends on 1) A method for determination and measurement of the rotor speed or position for a rotating shaft by means of an angular position encoder according to claim 1, wherein at least one reference pattern of the chain is created for determination and measurement of the rotor speed or position, and a comparison between at least one pattern and an actual measurement value takes place. ### Claim 16 (depends on 15) The method according to claim 15, wherein the measurement process is initiated by identification of parameters relevant for the measurement and a calibration of the materialized measure. ### Claim 17 (depends on 16) The method according to claim 16, wherein the configuration comprises searching for a synchronization point. ### Claim 18 (depends on 15) The method according to claim 15 further comprising recording and storing a signal minimum and maximum, determining an offset of a chain element from the minimum and maximum values of the signal and identifying an amplitude. ### Claim 19 (depends on 15) The method according to claim 15 wherein creating at least one reference pattern takes place at a fixed interval and is regularly updated. ### Claim 20 (depends on 15) The method according to claim 15 wherein the comparison of the at least one pattern and an actual measurement valve comprises identifying a synchronization point. ### Claim 21 (depends on 20) The method according to claim 20, wherein identifying the synchronization point comprises identifying a rising edge of the maximum value of the signal. ### Claim 22 (depends on 20) The method according to claim 20, wherein identifying the synchronization point comprises identifying the difference between two measurement points, wherein the same measurement points are always compared with one another. ### Claim 23 (depends on 20) The method according to claim 20, wherein identifying the synchronization point comprises adding the measurement values of two offset sensors. ### Claim 24 (depends on 15) The method according to claim 15 wherein the speed or position identification comprises recording the number of chain elements multiplied by a chain element length in relation to the shaft circumference. ### Claim 25 (depends on 15) The method according to claim 15 further comprising an additional recording is performed of the section of a chain element in which the sensor is positioned during speed or position determination. ### Claim 26 (depends on 25) The method according to claim 25, wherein the local position determination is identified by the equation: X = sin - 1  ( y - D A ) wherein X is the local position of the respective chain element; y is the measurement value of the sensor; A is the amplitude of the respective chain element; and D comprises the offset of the respective chain element. ### Claim 27 (depends on 15) The method according to claim 15 wherein the position determination comprises clockwise/anticlockwise detection of the shaft. ### Claim 28 (depends on 1) A wind turbine of the type having a rotor rotatable about a rotor axis having a rotor hub, a rotor shaft and at least one rotor blade secured to the rotor hub and running in a direction substantially transverse to the rotor axis, and at least one electrical generator mechanically coupled to the rotor shaft, the improvement comprising an angular position encoder according to claim 1 for identifying the rotor speed and position. ### Claim 29 (depends on 15, 28) The wind turbine according to claim 28, wherein determination and measurement of the rotor speed and position is performed according to the method of claim 15.