Relative angle detection device, rotation angle detection device, relative angle detection method, and rotation angle detection method

摘要

Disclosed is a relative angle detection device for detecting a relative angle between a first rotary shaft and a second rotary shaft, the relative angle detection device being provided with a first magnetic field sensing unit which outputs a value according to a magnetic field of a magnet, a second magnetic field sensing unit which outputs a value according to the magnetic field of the magnet and outputs a value different from the output value of the first magnetic field sensing unit even if being placed in the same magnetic field as that of the first magnetic field sensing unit, a correction unit which corrects one output value out of the output value of the first magnetic field sensing unit and the output value of the second magnetic field sensing unit in accordance with an amplitude ratio between magnetic field components orthogonal to each other in the magnetic field of the magnet, and a computing unit which computes the relative angle between the first rotary shaft and the second rotary shaft on the basis of the one output value corrected by the correction unit and the other output value different from the one output value. Consequently, a technique capable of detecting the relative rotation angle with high accuracy is provided even if magnitudes of amplitudes of magnetic field components orthogonal to each other in the magnetically sensitive surface of the magnetic field sensing unit are different from each other.

主权项

1. A relative angle detection device that detects a relative angle between a first rotary shaft and a second rotary shaft, the relative angle detection device comprising:
a magnet that is provided to any one rotary shaft out of the first rotary shaft and the second rotary shaft; a first magnetic field sensing unit that is provided to the other rotary shaft different from the one rotary shaft, and outputs a value according to a magnetic field of the magnet; a second magnetic field sensing unit that is provided to the other rotary shaft, outputs a value according to a magnetic field of the magnet, and outputs a value different from an output value of the first magnetic field sensing unit even if being placed in a magnetic field equal to a magnetic field of the first magnetic field sensing unit; a correction unit that corrects any one output value out of the output value of the first magnetic field sensing unit and an output value of the second magnetic field sensing unit in accordance with an amplitude ratio between magnetic field components orthogonal to each other in the magnetic field of the magnet; and a computing unit that computes a relative angle between the first rotary shaft and the second rotary shaft on the basis of the one output value having been corrected by the correction unit and the other output value different from the one output value.