Apparatus and associated methods relate to cascaded sets of two or more individual permanent magnets distributed in a predetermined spatial relationship on a source carrier configured to translate proximate two or more magnetic field sensors distributed in a predetermined spatial relationship on a reference carrier. In an illustrative example, the permanent magnets may be arranged in at least two predetermined orientations. For example, each of the permanent magnets may direct its field in a predetermined orientation to produce a unique output code from a set of the magnetic field sensors. The output code may, for example, uniquely identify a relative position between the source carrier and the reference carrier. The magnetic field sensors may be, for example, anisotropic magneto-resistive elements. Cascaded sets of permanent magnets may cost-effectively increase the dynamic range of the relative position between the source carrier and the reference carrier by adding additional magnetic targets.

The various embodiment of the present disclosure provides a system to define and identify an absolute mechanical reference position for a rotating element, The system comprises a radial ring magnet comprising plurality of pole pairs mounted to the rotating element, a first magnetic sensor in proximity of the radial ring magnet to detect angular position of said rotating element, at least one second magnetic sensor in proximity of the radial ring magnet to detect the passage of each of the pole pair and a control module adapted to define said absolute mechanical position by computing a unique first set of feature values for each of said plurality of pole pairs based on responses of said first magnetic sensor and said second magnetic sensor. The first set of feature values is stored in a memory unit.

There is provided an absolute encoder advantageous in accuracy of an output thereof against a defect in a scale thereof. In the absolute encoder, a detector detects a part of an array of marks of the scale, and outputs a data sequence corresponding to the part. A processor stores information indicating a correspondence between each of a plurality of code sequences and an absolute coordinate of motion of the scale, and outputs information of the absolute coordinate based on the data sequence and the information. The processor detects an error of the data sequence, and performs rewriting of the information based on the detected error.

A measuring device for a spindle or for a rotary table includes at least two first and second position sensing elements and a scale element, having a first and second graduations and being rotatable about an axis of rotation relative to the position sensing elements. The first graduation includes regular structures arranged in parallel next to one another along a first direction, having a directional component in the circumferential direction. The second graduation includes regular structures arranged in parallel next to one another along a second direction, having a directional component in the axial direction. The first position sensing elements are offset from one another in the circumferential direction, and are able to scan the first graduation so that the position of the scale element in a plane having an orthogonal orientation to the axis of rotation is determinable. In addition, at least one of the first position sensing elements is able to determine an angular position of the scale element in relation to the first position sensing elements in absolute terms within and across a rotation. The second position sensing elements are offset from one another in the circumferential direction, and are able to scan the second graduation, and the axial position of the scale element is able to be determined.

A rotary position encoder includes a detection unit and a scale co-configured and co-operative to detect a relative rotational position and to generate a position output accordingly. The scale has a scale pattern according to a linear-feedback shift register (LFSR) pseudo-random code, which is a non-maximal length code having a seed value, tap positions, and modified least-significant bit position(s) of code words that satisfy rotary constraint by which each code word follows in sequence from the adjacent code word.

There is provided a displacement measuring apparatus capable of being used in a vacuum environment. The displacement measuring apparatus includes a scale and a detection head part disposed in such a manner as to be relatively displaceable to the scale and as to face the scale with a predetermined gap. The detection head part detects a displacement or position relative to the scale. The scale is disposed in a vacuum. The detection head part is housed in a housing holder separating an atmospheric environment side from a vacuum environment side. In a gap between the detection head part and the scale, the housing holder includes a relay means for passing a detection signal between the detection head part and the scale,

A position-measuring device and a corresponding method for measuring an absolute position includes a material measure having a first binary code and a second binary code and a sensor device that scans the first and second binary codes. The sensor device scans the first binary code, which has a first number of code words, each having the same code word length. The second binary code of the material measure forms a portion of the first binary code and has a second number of the code words that can be mapped onto the first binary code.

The invention concerns a device and a method for measuring the relative position and angles between two bodies to be measured (7, 77). The invention is characterized in that it comprises one or more permanent magnets (6) and in that the position to be measured is determined indirectly via a magnetic field. The magnetic field is detected by one or more magnetic field sensors (3) read by a microchip. A mathematical minimization method is used to calculate back to the position and angles of the permanent magnet system (6) in relation to the magnetic field sensors (3). The energy required to read out the sensors can be obtained from the excitation field of a readout device. The sensor can perform without energy supply and can be read out by means of standard readout devices, such as an NFC-capable mobile telephone.

The optical encoder includes a scale, a head moves relative to the scale, and a calculating unit performs calculation based on the relative movement. The head includes a light source and a receiving unit having a light receiving surface. The scale includes a step portion on a scale surface. The step portion generates interference light having a contrast pattern on the light receiving surface, and generate the darkest portion with the highest contrast in the contrast pattern. The light source irradiates the step portion with light in a direction inclined with respect to a direction perpendicular to the scale surface. The calculating unit includes an origin calculating unit that identifies the darkest portion from the contrast pattern and calculates the identified darkest portion as the origin position that is a reference of the relative movement between the scale and the head.

Apparatus and associated methods relate to cascaded sets of two or more individual permanent magnets distributed in a predetermined spatial relationship on a source carrier configured to translate proximate two or more magnetic field sensors distributed in a predetermined spatial relationship on a reference carrier. In an illustrative example, the permanent magnets may be arranged in at least two predetermined orientations. For example, each of the permanent magnets may direct its field in a predetermined orientation to produce a unique output code from a set of the magnetic field sensors. The output code may, for example, uniquely identify a relative position between the source carrier and the reference carrier. The magnetic field sensors may be, for example, anisotropic magneto-resistive elements. Cascaded sets of permanent magnets may cost-effectively increase the dynamic range of the relative position between the source carrier and the reference carrier by adding additional magnetic targets.