An electronic absolute position encoder is provided including a scale, a detector portion and a signal processing configuration. The scale includes a first scale pattern of signal modulating elements, wherein the first scale pattern includes a spatial characteristic of the signal modulating elements which progressively changes as a function of position along a measuring axis direction and defines an absolute measuring range. The spatial characteristic includes at least one of a spatial wavelength or a spatial frequency of the signal modulating elements and is unique at each unique position in the absolute measuring range. The detector portion includes a group of sensing elements, and the signal processing configuration determines an absolute position of the sensing elements relative to the scale within the absolute measuring range. In various implementations, the signal processing configuration may utilize Fourier transform processing and/or other processing for determining the absolute position.

A magnetic encoder comprising an encoder element having at least two tracks of encoder regions, each region comprising a magnetic pole, the poles along each track being arranged as an alternating pattern of North and South poles, and one or more sensors, each sensor comprising one or more sensing elements associated with a respective track and generating an output that is indicative of the magnetic field associated with that track in the vicinity of the sensor, in which at least one track has a differing number of poles to at least one of the other tracks, and in which the properties of the poles of a first one of the tracks differ along the track such that there is a periodic variation along the first track of the magnetic field emitted by the first track that is detected by the sensing elements associated with the first track which at least partially cancels out a corresponding periodic variation in field from the other tracks that is also detected by the sensing elements associated with the first track.

Disclosed is linear displacement absolute position encoder used for measuring displacement of a tested apparatus. The linear displacement absolute position encoder comprises a base, a magnetoresistive sensor array, an encoding strip, and a back magnet. The encoding strip is fixed on the base and extends in the direction of a rail of the tested apparatus. The encoding strip is a magnetic material block having recess and protrusion for identifying encoding information of different positions. The magnetoresistive sensor array is arranged between the encoding strip and the back magnet in a non-contact manner. The back magnet is used for generating a non-uniform magnetic field around the encoding strip so as to magnetize the encoding strip. The magnetoresistive sensor array is used for acquiring the position encoding information of the encoding strip by detecting magnetic field information of the encoding strip. The encoder is low cost and can monitor large distances.

An absolute encoder configured to, when a rotation range of a measurement target member is limited by a brake mechanism, generate an AB-phase signal and a Z-phase signal for calculating a rotation angle of the measurement target member. The absolute encoder includes a brake mechanism, a plurality of Z-phase-signal-detection-target portions each having a Z-phase-signal-rise-detection-target portion and a Z-phase-signal-fall-detection-target portion, a plurality of AB-phase-signal-detection-target portions each located between a Z-phase-signal-rise-detection-target portion and a Z-phase-signal-fall-detection-target portion that are adjacent to each other in a circumferential direction, to thereby form a plurality of restriction ranges each including at least one of the Z-phase-signal-rise-detection-target portions and at least one of the Z-phase-signal-fall-detection-target portions. An interval in the circumferential direction between a Z-phase-signal-rise-detection-target portion and a Z-phase-signal-fall-detection-target portion that are adjacent to each other in the circumferential direction is different among the plurality of restriction ranges.

Detection accuracy of a rotation angle of a sub-shaft is to be improved. In an absolute encoder according to an embodiment of the present invention, a second worm wheel part is a second driven gear, has a central axis orthogonal to a central axis of a first worm wheel part, and meshes with a second worm gear part. A support shaft rotatably supports the second worm wheel part. A magnet (Mq) rotates integrally with the support shaft. An angle sensor (Sq) is provided near the magnet (Mq) and detects a change in a magnetic flux generated from the magnet (Mq). A first bearing has an outer ring fixed at the second worm wheel part and an inner ring fixed at the support shaft. A second bearing has an inner ring fixed at the support shaft.

An inductive angle measuring device includes a scanning element and a scale element having scale tracks. First and third scale tracks have an equal first number of scale structures, and a second scale track has a different number of scale structures. The scale tracks are arranged circumferentially and concentrically about an axis, such that the first scale track is located radially inwardly, the second scale track is located radially between the first scale track and the third scale track, and the third scale track is located radially outwardly. The scanning element includes receiver conductors by which the signals having angle-related signal periods can be generated. The first signal period is equal to the third signal period. An overall signal can be generated from the first signal and the third signal and can be combined with the second signal for determining absolute angle position information.

A rotary transducer is described. The rotary transducer includes a Hall effect sensor, a rotary dial comprising at least two recessed pockets, a first magnet that is positioned within one of the at least two recessed pockets, and a second magnet that is positioned within another one of the at least two recessed pockets. In an acceleration only mode, the rotary dial is rotatable from a center position in a first direction and is not rotatable from the center position in a second direction. This mode is selected when a mode selection screw is inserted into a mode selection orifice. In a bi-directional acceleration/deceleration mode, the rotary dial is rotatable from the center position in the first direction and is rotatable from the center position in the second direction. This mode is selected when the mode selection screw is not inserted into the mode selection orifice.

A method of correcting a position reading from a position sensing arrangement. The position sensing arrangement is suitable for sensing the position of a revolute joint of an articulated structure, and comprises a disc having a magnetic ring with magnetic pole pairs and a magnetic sensor assembly comprising a magnetic sensor array for detecting the magnetic pole pairs of the magnetic ring. The method comprises: for each pole pair of the magnetic ring, taking a calibration pole pair position reading with the magnetic sensor array, and generating a pole pair correcting function by comparing the calibration pole pair position reading with a model pole pair position reading; averaging the pole pair correcting functions of the pole pairs of the magnetic ring to generate an average pole pair correcting function for the magnetic ring; taking a position reading with the magnetic sensor array, the position reading comprising a plurality of pole pair position readings; and generating a corrected position reading by deducting the average pole pair correcting function from each pole pair position reading.

A magnetic encoder includes one or more sensors and an encoder element having at least two tracks of encoder regions. Each region comprises a magnetic pole. Each sensor has one or more sensing elements associated with a respective track and generates an output that is indicative of the magnetic field associated with that track. At least one track has a differing number of poles to at least one of the other tracks. The properties of the poles of a first one of the tracks differ along the track such that there is a periodic variation along the first track of the magnetic field emitted by the first track that is detected by the sensing elements associated with the first track which at least partially cancels out a corresponding periodic variation in field from the other tracks that is also detected by the sensing elements associated with the first track.

At a time that a position detecting device is initiated, an arithmetic processing unit calculates the absolute position of a rotating shaft at the time of initiation, on the basis of first to third analog signals corresponding to first to third angles of rotation, which are detected respectively by first to third rotational angle detectors. During rotation of the rotating shaft, a current position counter detects a current absolute position of the rotating shaft by counting a number of pulses of forward rotation pulses or reverse rotation pulses, corresponding to the first angle of rotation detected by the first rotational angle detector, taking as a standard a total number of pulses corresponding to the absolute position of the rotating shaft at the time of initiation.