To provide an angle detection method with which a control for positioning an output shaft using an input shaft encoder and output shaft encoder at a high accuracy and a torsional feedback control can be realized and an angle detection apparatus that executes the angle detection method. In a robot arm constituted by an input shaft encoder, an output shaft encoder, a motor, a reduction gear, and the like, an output shaft encoder detection error is corrected by setting rotation position information using a periodicity of rotations of the input shaft encoder as a reference. When the input/output shaft encoder detection error is corrected in this manner, the control for positioning the output shaft at a high accuracy and the torsional feedback control can be realized.

To suppress deterioration in the detection accuracy of a rotation angle of a magnet even when a member located in the vicinity of the magnet is made of a magnetic material. An absolute encoder includes a first sub-shaft gear configured to rotate based on rotation of a main shaft, a bearing part configured to rotatably support the first sub-shaft gear around an axial line A, a support shaft configured to support the bearing part, and a spacer provided between the first sub-shaft gear and the bearing part. At least a part of the spacer is formed of a magnetic material, and the spacer is formed extending in a direction intersecting the axial line A.

The invention relates to a sensor system (1), and a method for determining an absolute rotation angle () of a shaft (10) with a rotation angle range of more than one revolution and to a vehicle fitted with a sensor system (1), wherein the sensor system (1) has a main rotor (2) that can be connected rotationally synchronously to the shaft (10), a first auxiliary rotor (3) which is mechanically coupled to the main rotor (2), a second auxiliary rotor (4) mechanically coupled to the main rotor (2), a first sensor device (SE1) which is assigned to the first auxiliary rotor (3) for generating a first sensor signal dependent on a rotation angle of the first auxiliary rotor (3), a second sensor device (SE2) which is assigned to the second auxiliary rotor (4) for generating a second sensor signal dependent on a rotation angle of the second auxiliary rotor (4), a third sensor device (SE3) which is assigned to the main rotor (2) and which is used for generating a third sensor signal dependent on a relative rotation angle () of the main rotor (2) and an evaluation device for determining the absolute rotation angle () of the main rotor (2) from the sensor signals of the sensor devices (SE1, SE2, SE3). The detection range () of the third sensor device is less than 360.

Provided is a sensor device that is machinable and mountable easily. A sensor device includes an external gear configured to rotate together with a pinion shaft, driven gears configured to rotate by meshing with the external gear, permanent magnets configured to rotate together with the driven gears, magnetic sensors configured to detect magnetic fields of the permanent magnets, a circuit board assembly having the magnetic sensors mounted on a printed circuit board, a tubular first housing member that houses the external gear, and a second housing member that supports the driven gears and houses the circuit board assembly. The second housing member has a flange portion that abuts against an open end face of a fitting hole of the first housing member, and parts of the driven gears that protrude from the flange portion mesh with the external gear inside the first housing member.

Detection accuracy of a rotation angle of a sub-shaft is to be improved. In an absolute encoder according to an embodiment of the present invention, a second worm wheel part is a second driven gear, has a central axis orthogonal to a central axis of a first worm wheel part, and meshes with a second worm gear part. A support shaft rotatably supports the second worm wheel part. A magnet (Mq) rotates integrally with the support shaft. An angle sensor (Sq) is provided near the magnet (Mq) and detects a change in a magnetic flux generated from the magnet (Mq). A first bearing has an outer ring fixed at the second worm wheel part and an inner ring fixed at the support shaft. A second bearing has an inner ring fixed at the support shaft.

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 system for detecting the absolute rotational angle of a shaft rotatable more than one revolution includes a drive wheel connected to the shaft to rotate therewith. The drive wheel includes measurement sectors adjacent to one another in a circumferential direction. First and second driven wheels are engaged to the drive wheel. First and second sensors monitor rotational positions of the driven wheels to thereby detect an absolute rotational angle of the shaft. A third sensor monitors a relative angular position of the shaft in relation to a detected one of the measurement sectors to thereby detect the relative angular position of the shaft within one revolution of the shaft. The detected absolute rotational angle of the shaft is refined with the detected relative angular position of the shaft to thereby generate the absolute rotational angle of the shaft with more precision.

A detection device includes: a sensor that outputs first and second sensor outputs behaving respectively differently according to a change in a rotation angle of an object; a target calculation unit that calculates first and second target angles hat are target values of first and second actual angles corresponding to the first and second sensor outputs; and a selection unit that selects, as a reference destination, one of the first and second sensor outputs for driving the object.

A rotary position sensor comprises a magnetic sensor for generating two independent signals indicative of at least two different order magnetic fields, and a magnetic assembly forming a first magnetic field component having a first order at the location of the magnetic sensor, in which the first magnetic field component is rotatable relative to the magnetic sensor by receiving a first angle. The magnetic assembly is also adapted for forming a second magnetic field component having a second order, different from the first order, at the location of the magnetic sensor, in which the second magnetic field component is rotatable relative to the magnetic sensor and the first magnetic assembly by receiving a second angle. The position sensor comprises a processor for combining the two independent signals to produce a unique system state representative of the first and second angle.

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.