An integrated circuit for error detection comprises an input for receiving two signals, in which a first signal is representative of a physical quantity in a first range and a second signal is representative of the physical quantity in a second range. The first range and second range are different ranges that overlap. The circuit comprises a processor configured to detect an inconsistency between the two signals by taking said first and second range into account, in which this inconsistency is indicative of an error.

A multi-turn detector is configured to detect an amount of multiple turns of an input shaft using a plurality of resolvers. Each resolver includes a rotor portion and a stator portion. The rotor portion has a rotor core composed of a magnetic flux modulating component. The rotor portion rotates in accordance with rotation of the input shaft at a reduction gear ratio that is different from that of a rotor portion of another resolver. The stator portion has an excitation winding that excites an ac magnetic flux in a direction of an axis of rotation of the rotor portion and two detection windings that output ac signals that are obtained by performing amplitude modulation in accordance with a rotation angle of the rotor portion. The excitation windings and the detection windings of the plurality of resolvers are formed by conductor traces in a common multi-layer printed circuit board.

A displacement measurement mechanism for automated equipment is provided, wherein the automated equipment at least includes an equipment base, at least one load-bearing linear slide rail disposed along and parallel to a machining axis of the automated equipment, a driving unit parallel to the load-bearing linear slide rail, and a sliding table coupled to the load-bearing linear slide rail and the driving unit. The displacement measurement mechanism includes a non-load-bearing linear slide rail disposed on the equipment base and adjacent to the machining axis, a graduation disposed on the non-load-bearing linear slide rail and parallel to the machining axis, a linear slide base slidably coupled to the non-load-bearing linear slide rail and also coupled to the sliding table without bearing the load of the sliding table, and a read head coupled to the linear slide base and corresponding to the graduation.

A rotation angle detection device includes a driving gear rotated integrally with a rotary body, a first driven gear and a second driven gear coupled to the driving gear and rotated in cooperation with the driving gear, a first sensor that detects rotation of the first driven gear and generates a first sensor output, and a second sensor that detects rotation of the second driven gear and generates a second sensor output. An initialization method includes adjusting zero points of the first and second sensor output obtained at positions of rotation references of the first and second driven gears, measuring a deviation amount occurring in a calculation of rotation information of at least one of the first and second driven gears, and correcting the zero point of at least one of the first and second sensor outputs based on the measured deviation amount.

A rotational angle detection device includes a first gear that rotates about a first rotation axis and that has a main surface having an annular shape that crosses the first rotation axis and a plurality of first teeth provided on the main surface; a second gear that rotates about a second rotation axis in engagement with the first gear and that has a larger number of second teeth than the first teeth; and a sensor that detects a rotational angle of the second gear. The second rotation axis extends in a direction orthogonal to both of a virtual line that connects a center of the first gear and a position where the first gear and the second gear are engaged with each other, and the first rotation axis. Each of the first teeth extends so as to shift from an outer side toward an inner side in a radial direction of the main surface as it shifts along a circumferential direction of the main surface. Adjacent two of the first teeth are disposed so as to overlap each other in the radial direction.

An absolute encoder preferable in being made compact is provided. The absolute encoder includes a first drive gear, a first permanent magnet, a first angle sensor, and a first driven gear of a central axis that is perpendicular to a central axis of the first drive gear, the first driven gear engaging with the first drive gear. The absolute encoder includes a second drive gear coaxially provided with the first driven gear, the second drive gear being configured to rotate in accordance with rotation of the first driven gear. The absolute encoder includes a second driven gear of which a central axis is perpendicular to the central axis of the first driven gear, the second driven gear engaging with the second drive gear. The absolute encoder includes a second permanent magnet provided on a top end side of the second driven gear. The absolute encoder includes a second angle sensor configured to detect a rotation angle of the second driven gear, in accordance with a change in magnetic flux generated from the second permanent magnet. A reduction ratio between the first drive gear (worm gear (101c)) and the first driven gear (worm wheel (102a)) is set to a value for mitigating an effect of backlash between the first drive gear and the first driven gear, the backlash resulting in an error in the rotation angle of the second driven gear.

An absolute encoder suitable for size reduction is provided. An absolute encoder includes: a first driving gear configured to rotate according to rotation of a spindle; a first driven gear having a center axis perpendicular to a center axis of the first driving gear and configured to engage with the first driving gear; and a second driving gear provided coaxially with the first driven gear and configured to rotate according to rotation of the first driven gear. The absolute encoder includes a permanent magnet (8) provided on a layshaft gear (5A) having a center axis perpendicular to the center axis of the first driven gear and where a worm wheel portion (52e) is formed to engage with the second driven gear; and a resin sheet (5A1) provided on the layshaft gear (5A) to prevent the permanent magnet (8) from coming out from the layshaft gear (5A) in the axial direction.

In an encoder device, a first gear is made of a transparent resin allowing transmission of light and includes: a detection target on which an optical pattern for detecting the absolute rotation angle within one rotation is formed, and a plurality of teeth formed on the outer periphery of the detection target. A first sensor includes a light emitter configured to emit light toward the detection target and a light receiver configured to receive the light transmitted through the detection target.

An influence of use orientation on detection accuracy is reduced. A magnetism detection device includes a magnet (Mr) magnetized, an angle sensor (Sr) as a magnetic sensor configured to detect a magnetic flux from the magnet (Mr), a magnet holder holding the magnet (Mr), and a second layshaft gear shaft. The magnet holder is rotatably supported on the second layshaft gear shaft. The second layshaft gear shaft is made of a magnetic material. An attractive force due to a magnetic force is generated between the magnet (Mr) and the second layshaft gear shaft in a direction of a rotation axis of the magnet holder.

A rotation angle detection device includes a correction-object driven gear that is a driven gear meshing with a main driving gear, a first sensor that is configured to generate an electrical signal based on rotation of the correction-object driven gear, and an electronic control unit that computes a driven-side rotation angle based on the electrical signal. The electronic control unit is configured to store a correction angle used to correct the driven-side rotation angle when computing the driven-side rotation angle. The correction angle is a predetermined deviation in a predetermined angle domain obtained as an average value in which deviations of the number equal to the integer and corresponding to a same relative rotation angle is averaged, so as to be deviation in an angle domain of 0 to 360 degrees.