An encoder includes a main body and a toothed encoding unit. The main body is made of material with magnetic permeability. The toothed encoding unit is made of material with magnetic permeability, and includes a toothed encoding set and a position toothed encoding set that are disposed on the main body. The toothed encoding set includes a plurality of recesses that are disposed in a first direction. Each of the recesses of the toothed encoding set extends in a second direction that is transverse to the first direction. The position toothed encoding set includes a plurality of recesses that are disposed in the second direction. Each of the recesses of the position toothed encoding set extends in the first direction.

A magnetic encoder has an annular main body and a magnetic encoding unit. The main body is made of material with magnetic permeability, surrounds a central axis, and includes a first surface and a second surface opposite to said first surface. The magnetic encoding unit is disposed on one of the first surface and the second surface of the main body, and includes a plurality of first and second magnetic poles, each of which is annular and is centered at the central axis. The first and second magnetic poles are arranged in an alternating sequence.

A position detecting apparatus includes a signal detecting unit that detects a plurality of periodic signals, a correction unit configured to correct the plurality of periodic signals using a correction value to generate a plurality of correction signals, a first calculating unit configured to generate a plurality of displacement signals based on the plurality of correction signals and to calculate the position based on the plurality of displacement signals, a second calculating unit configured to calculate a reliability based on the plurality of displacement signals, and a correction value adjusting unit configured to adjust the correction value based on the reliability. The second calculating unit calculates a first reliability corresponding to a first correction value and a second reliability corresponding to a second correction value, and changes the first correction value to the second correction value when the second reliability is higher than the first reliability.

According to an embodiment, an encoder system includes an encoder and an interface. The encoder detects the position and speed of a motor, and generates A-, B- and Z-phase signals. The interface includes an AB waveform recognition circuitry to recognize a waveform of an AB phase, a Z waveform recognition circuitry to recognize a period of an enable state of a Z phase, a starting point storage device to store a value of the AB phase when the Z phase changes and stores an AB-phase change pattern, a starting point recognition circuitry to generate an interrupt signal, and a rotation angle counter to start a new count of the rotation angle of the motor.

An angle sensor system includes a magnetic field generation unit for generating a rotating magnetic field, and an angle sensor for detecting the rotating magnetic field to generate a detected angle value. The rotating magnetic field contains first and second magnetic field components orthogonal to each other. Each of the first and second magnetic field components contains an ideal magnetic field component, and an error component corresponding to the fifth harmonic of the ideal magnetic field component. The angle sensor includes first and second detection signal generation units. Each of the first and second detection signal generation units includes a magnetic layer whose magnetization direction varies according to the direction of the rotating magnetic field. The magnetic layer is provided with a magnetic anisotropy that is set to reduce an angular error resulting from the error components of the first and second magnetic field components.

A sensor device comprises a sensor unit for generating a signal indicative of a physical quantity. The device comprises a processing unit for receiving the signal, in which the processing unit comprises a storage memory for storing data derived from the signal as provided by the sensor unit at at least two points in time. The device comprises a bus interface for communicating with an electronic control unit via a digital communication bus. When a read command is received from the electronic control unit, an estimate of the physical quantity is sent in response to the electronic control unit. The processing unit comprises an estimator for calculating the estimate at a reference point in time based on the data stored in the storage memory, in which the reference point in time differs from the point in time at which the read command is received by substantially a predetermined offset.

In a control device for an AC rotary machine, having an angle detector for detecting an electrical angle of the AC rotary machine, a detection error produced by the angle detector due to a noise magnetic field generated by a multi-phase alternating current flowing through an inverter connection unit is corrected using a correction signal having a phase and an amplitude that are determined in accordance with a relative positional relationship between the inverter connection unit and the angle detector and a current vector of the multi-phase alternating current, whereupon an inverter is controlled on the basis of the corrected electrical angle. As a result, a simple, low-cost control device for an AC rotary machine with which an angular position of a rotor can be detected with a high degree of precision is obtained.

An encoder according to an example of the present disclosure includes a first reception unit configured to receive a position information request signal for requesting position information on an object to be detected, a position information generation unit configured to generate the position information at a position information generation timing after a predetermined delay time elapses from when the position information request signal is received, and a first transmission unit configured to transmit the position information to the outside via serial communication. The first transmission unit is configured to transmit, at least once, position information generation timing information representing the predetermined delay time to the outside via serial communication.

A rotary encoder includes a control part having a storage section storing a plurality of parameters regarding error signal components at a reference rotation speed, the error signal components respectively being superposed on an A-phase signal and a B-phase signal in proportion to a rotation speed of a rotor body, and a rotation speed calculation section structured to measure a reception interval of a requirement signal and calculate a current rotation speed of the rotor body. The control part is structured to convert a parameter stored in the storage section to a value at the current rotation speed based on a ratio between the reference rotation speed and the current rotation speed, correction processing correcting the A-phase signal and the B-phase signal is executed based on the value converted, and the rotation position of the rotor body is calculated by using a corrected A-phase signal and a corrected B-phase signal.

A correction apparatus for an angle sensor includes a correction processing unit, an indicator value generation unit, and a correction information determination unit. The correction processing unit performs correction processing on a plurality of detection signals to reduce an error of a detected angle value. The details of the correction processing are determined according to correction information. The indicator value generation unit generates, on the basis of the plurality of detection signals, an indicator value having a correspondence with the error of the detected angle value. The correction information determination unit generates an estimated indicator value using a function that takes one or more values each having a correspondence with the correction information as one or more variables, and determines the correction information by adaptive signal processing so as to reduce the difference between the indicator value and the estimated indicator value.