Systems and methods for detecting magnetic turn counter errors with redundancy are provided. In one aspect, a magnetic field turn sensor system includes a magnetic field angle sensor having a sine bridge and a cosine bridge and first to third comparators configured to compare the outputs from the sine and cosine bridges. The system further includes a processor configured to receive outputs from each of the first to third comparators, determine that a combination of the outputs from the first to third comparators corresponds to an invalid state, and indicate a fault in response to determining that the combination of the outputs from the first to third comparators corresponds to the invalid state.

To provide an abnormality detection apparatus for resolver which can determine the abnormality of at least the first system, even if the period of the excitation AC voltage of the first system and the period of the excitation AC voltage of the second system are different periods, and the magnetic interference between systems occurs. An abnormality detection apparatus for resolver applies an AC voltage of a first period to a first system excitation winding; applies an AC voltage of a second period different from the first period to a second system excitation winding; calculates DC values of first system two output signals by performing a DC extraction processing; and determines abnormality of first system based on whether or not the DC values of first system two output signals are within a normal range.

A failure detection device for a steering angle sensor according to an embodiment comprises: a steering angle sensor including a main gear that rotates together with a steering wheel, a first sub-gear and a second sub-gear that are each engaged with the main gear and have a constant gear ratio with the main gear, a first Hall IC chip for detecting the angle of the first sub-gear, and a second Hall IC chip for detecting the angle of the second sub-gear; and a control unit that determines failure of the steering angle sensor on the basis of a first angle difference between the current angle and a previous angle of the first sub-gear as detected by the first Hall IC chip, and a second angle difference between the current angle and a previous angle of the second sub-gear as detected by the second Hall IC chip.

A method of operating a position encoder apparatus, including a scale having features defining position information and a readhead for reading the scale. The method includes: calculating extrapolated position information from at least one previous reading of the scale; comparing an extrapolated position with a position calculated from a reading of the scale to determine any discrepancy between them; using the extrapolated position information whether or not there is a discrepancy; and maintaining a record of any discrepancies.

A dual encoder system includes first and second encoders on a single printed circuit board mounted on an electric motor. Each encoder independently generates feedback information used by motor and safety controllers for controlling the motor. A single magnet is mounted on the motor shaft. The first encoder cooperates with the magnet to provide first encoder information to the motor controller regarding magnetic alignment between a rotor and a plurality of stator windings of the motor and regarding real-time position and velocity. The second encoder cooperates with the same magnet to provide second encoder information to a safety controller, wherein the second encoder information should be identical to the first. The safety controller may receive the first encoder information from the motor controller, compare the second encoder information to the first encoder information, and brake the electric motor if the second encoder information is different from the first encoder information.

An apparatus for detecting a failure of a motor drive circuit includes an encoder for detecting rotation information of a motor. The apparatus also includes an interface configured to transmit rotation information detected by the encoder to a processor. The apparatus also includes the processor configured to control the motor based on the rotation information of the motor and configured to receive through the interface and detecting a failure of the interface.

An actuator position sensing system for sensing a position of an actuator. The actuator position sensing system includes a first sensor for detecting a position of a first moveable portion of the actuator; a plurality of second sensors each being configured for detecting a position of a second moveable portion of the actuator; and a controller connected to the first sensor and the plurality of second sensors. The controller is configured to calculate a difference between (i) a position of the second movable portion as calculated based upon the data transmitted from the first sensor, and (ii) a position of the second movable portion as calculated based upon the data transmitted from one or more of the plurality of second sensors. A motor is connected to the first movable portion and the controller, and the motor is configured to move the first moveable portion based upon the calculated difference.

A rotation detection apparatus, a rotation angle detection apparatus are provided which allow appropriate detection of an abnormality in a portion that detects rotation of a rotating shaft. A first arithmetic circuit calculates a rotating direction and a number of rotations of the rotating shaft based on a change in a combination of positivity and negativity of a first electric signal (first sine signal) and a third electric signal (first cosine signal). A second arithmetic circuit calculates a rotating direction and a number of rotations of the rotating shaft based on a change in a combination of positivity and negativity of a second electric signal (second sine signal) and a fourth electric signal (second cosine signal). An abnormality determination circuit determines whether each of the first and second arithmetic circuits and is abnormal based on the two rotating directions and calculated by the first and second arithmetic circuits respectively.

The invention relates to a method for monitoring at least two redundant sensors, which are in particular arranged in a chemical plant or an aircraft, comprising providing a first sensor signal of a first sensor, the first sensor signal comprising at least one measured value, providing at least one further sensor signal from a further sensor, the further sensor signal comprising at least one further measured value, generating a first analysis signal from the first sensor signal, generating at least one further analysis signal from the further sensor signal, determining at least one relationship between the first sensor signal and the further sensor signal at least in dependence on the first analysis signal and the further analysis signal over a time horizon, comparing the relationship with at least one admissible range, and, depending on the result of the comparison, determining whether at least one sensor of the two redundant sensors is faulty.

A device for detecting and monitoring crank shaft rotary speed and position in a four stroke engine, wherein a first and a second sensor are arranged to sense passage of reference marks on a rotatable element or elements. The first sensor is a high precision sensor which is arranged to sense passage of reference marks on a crank shaft flywheel of the engine, and the second sensor is a low speed sensor which is arranged to sense passage of reference marks on the crank shaft flywheel or reference marks or a wheel being associated with a cam shaft of the engine. The invention also concerns a method and a vehicle.