Oriental Motor Co., Inc.

Akihiko Houda

Masayuki Someya

Masaharu Furuta

A motor control device controls an AC motor by sensorless control. The motor control device includes: an inverter; a multilayer printed circuit board including an inner layer having a wiring pattern provided in a current line connecting the inverter to a winding of the AC motor; a plurality of chip inductors mounted on a major surface of the multilayer printed circuit board in opposed relation to the wiring pattern, and connected in series to form a series circuit having a midpoint connected to a reference potential; load resistors connected between the midpoint of the series circuit and the opposite ends of the series circuit; a differential amplification circuit connected to the series circuit; and a control unit that estimates the position of the rotor of the AC motor by using an output of the differential amplification circuit, and generates the pulse width modulation signal to be supplied to the inverter.

Motor control device

A stepping motor control device is provided, which controls a stepping motor including a rotor position detector by micro-step driving. The control device has a plurality of operation modes including an adjustment mode and a use mode. In the adjustment mode, the control device generates control data for a closed loop control for controlling the winding current of the stepping motor based on the detection value of the rotor position detector, and performs a stepping motor acceleration operation and a stepping motor deceleration operation according to the control data. In the use mode, the control device performs the stepping motor acceleration operation and the stepping motor deceleration operation so that a winding current observed in the adjustment mode is reproduced by an open loop control for controlling the winding current of the stepping motor based on the control data generated in the adjustment mode.

Control device for stepping motor

Some embodiments include an absolute displacement detection device configured to calculate, from a plurality of displacement detection signals provided by a plurality of displacement detection mechanisms that detect displacement amounts, an absolute periodic signal having an absolute periodic signal period larger than displacement detection signal periods of the plurality of the displacement detection signals. Other embodiments of related devices and methods are also disclosed.

Device and method for calculating absolute amount of displacement, and method for same

This detection device is configured from a gear mechanism () provided with first to third counter-shaft gears that mesh with a main-shaft gear (), and has a relationship in which the difference between the numbers of teeth of the main-shaft gear and the first counter-shaft gear is two or an integer (a) exceeding two, the difference between the numbers of teeth of the main-shaft gear and the second counter-shaft gear is one, and the number of teeth of the first counter-shaft gear is an integral multiple of the product of the difference of the number of teeth thereof from that of the main-shaft gear and the shaft angle multiplier of a main shaft detector. The detected values of angle detectors (RS-RS) are given as digitized angle detected values (P, P, P, P) to a multi-turn arithmetic circuit (). The determination region of the detected value (P) of a main shaft is determined, and the rotation angle of the main shaft is found. Further, periodic signal values indicating the differences in rotation angle between the main shaft and first to third counter shafts are generated, respectively, and on the basis of a combination of the relative numbers of rotations of the first to third counter shafts found from the respective periodic signal values, the number of rotations of the main shaft is found. The multi-turn absolute rotation angle can be obtained by adding the rotation angle to the number of rotations of the main shaft.

Multi-turn absolute rotation angle detection device and method of detecting absolute rotation angle

There is provided a method for calculating with high accuracy a multi-turn absolute rotation angle of a motor rotating shaft coupled to a motor output shaft. In a rotation angle detection device according to this invention, a rotation angle &#x3b8;of an n-th rotating shaft satisfies the relationship with a rotation angle &#x3b8;of the motor rotating shaft: &#x3b8;=(&#x2212;(m&#xb1;1)/m)&#xd7;&#x3b8;. The rotation angle detection device as an embodiment of a mechanism satisfying the relationship includes a gear mechanism in which a gear having (m&#xb1;1) teeth meshes with a gear having m teeth between each adjacent two of first to n-th rotating shafts. A multi-turn rotation angle of the first rotating shaft is expanded to a detected value pof the first rotating shaft which is a rotation angle of the first rotating shaft and R&#xd7;m+R&#xd7;m+ . . . R&#xd7;mcorresponding to the number of revolutions of the first rotating shaft, coefficients Rto Rare obtained on the basis of detected values from angle detectors of the respective shafts, and the multi-turn rotation angle of the first rotating shaft is calculated. Detection errors generated in the angle detectors of the second and subsequent rotating shafts can be effectively reduced, and a high-accuracy multi-turn rotation angle can be calculated.

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Ibaraki, Japan

Akihiko Houda