Provided are an electromagnetic-induction-type position detector which can be small sized and in which interference errors do not occur, and a detection method. The present invention has: a stator having first and second main patterns and first and second sub-patterns; and a rotor having a main pattern part and a sub-pattern part, in which adjacent comb-shaped electrodes of the main pattern part and the sub-pattern part are connected to form a single loop; and when an excitation electric current is supplied to the first and second main patterns, an excitation voltage excited in the main pattern part is detected in the first and second sub-patterns via the sub-pattern part, and when an excitation electric current is supplied to the first and second sub-patterns, the excitation voltage excited in the sub-pattern part is detected in the first and second main patterns via the main pattern part.

A method for measuring a large shaft rotation angle utilizes one or more cams attached to the shaft. Each cam shape is designed to have one or more detectable harmonics when rotated. Multiple harmonics in a single cam or amongst multiple cams may have a particular order. Pairs of fine position sensors, positioned at opposing sense angle positions relative to the cam(s) measure displacement of the cam during rotation. The data from the position sensors is then analyzed, with a processor, to determine the large shaft rotation angle and angular displacement relative to an ideal axis of rotation.

An inductive sensor may track an angle of a movable element. In some cases, it is desirable to operate the inductive sensor using battery power so that turns are tracked properly even when power is lost. The disclosed inductive sensor includes circuitry to conserve power, such as a non-resonant driver that allows for fast measurements without wasting energy and a difference encoder that can estimate the angle within a range without the need for digitization and complicated processing.

A receiver coil of an inductive angular position sensor can have circuit features that become smaller than reasonable for high resolution measurement designs. This is especially true when multiple receiver coils are used, such as in a three-phase configuration, and when each of the multiple receiver coils is in a twisted loop configuration. The disclosed inductive angular position sensor utilizes different spatial frequencies for a rotor coil and the receiver coils. For example, the spatial frequency of the receiver coils may be kept smaller than the rotor coil. In this condition, the fundamental frequency of the angular position sensor is shifted to the least common multiple of the spatial frequencies, making the angular resolution of the inductive angular position sensor high, while the circuit features of the receiver coils are maintained at a reasonable size.

A receiver coil of an inductive angular position sensor can have circuit features that become smaller than reasonable for high resolution measurement designs. This is especially true when multiple receiver coils are used, such as in a three-phase configuration, and when each of the multiple receiver coils is in a twisted loop configuration. The disclosed inductive angular position sensor utilizes different spatial frequencies for a rotor coil and the receiver coils. For example, the spatial frequency of the receiver coils may be kept smaller than the rotor coil. In this condition, the fundamental frequency of the angular position sensor is shifted to the least common multiple of the spatial frequencies, making the angular resolution of the inductive angular position sensor high, while the circuit features of the receiver coils are maintained at a reasonable size.

A device for measuring a relative rotation speed and/or a relative angular position between a first rotating element (2) and a second rotating element (3). The device includes a structure for generating a magnetic field rotating at a magnetic rotation speed representing a rotation speed of the first rotating element and a sensor (5) mounted to rotate and adapted to produce from the rotating magnetic field a measurement signal representing the relative rotation speed and/or the relative angular position. The device also has a processor (11) positioned on the static part and intended to acquire the measurement signal. A transmitter is adapted to transmit the measurement signal to the processor from the sensor.

A position of a target is determined using a linear inductive position sensor that includes a target coil, an excitation coil, two sensors and a Vernier processor. The sensors each include two or more receive coils. The receive coils include multiple twisted loops. In the first sensor, the coils have a first period, with loops offset by first distance. In the second sensor, the coils have a second period, with loops offset by a second distance. The target coil width is a function of the first distance and the second distance. During operation, the coils output voltages in which third, fifth and/or seventh harmonics are cancelled. Based on the voltages, the sensors output respective first and second position signals, from which the Vernier processor calculates the target's position along an axis of the position sensor.