Hitachi, Ltd.

Seiichi Narushima

Fumio Tajima

Hiroshi Katayama

Kunio Miyashita

Shigeki Morinaga

Nobuyoshi Mutoh

Motoya Ito

Taizo Miyazaki

Taizou Miyazaki

Tunehiro Endo

Yuji Sato

Kouichi Saito

Toshio Nakamoto

Toshio Osada

Takashi Takahashi

Jun Ohya

Kiyoshi Yamamuro

Nicolas Samman

Kouchi Saito

A speed control apparatus in which for sampling features of a speed fluctuation and generating a speed fluctuation correcting signal, an arithmetic operation can be simplified and can be performed by an inexpensive arithmetic and operation unit, thus requiring no expensive arithmetic operation unit. The speed control apparatus is also capable of reducing torque ripples and speed fluctuations quickly even when the load of an object to be controlled is changed.

Apparatus for controlling the speed of a moving object

There is provided position error computing means for sampling an error value between a position detecting signal derived from means for detecting the position of a moving body and a position command signal supplied from outside and for computing a position error value on the basis of two or more past values of said error values. There is also provided a position control apparatus in which the magnitude of a gain of a position control loop is changed according to the above described position error value. Further, there is also provided a signal reproducing apparatus or a magnetic signal reproducing apparatus using the above described position control.

Moving body position control apparatus and signal reproducing apparatus

In order to provide a speed control apparatus for a movable equipment having small torque ripples and speed variation, the present invention has a speed control means which comprises a driver for providing a current or a voltage having a magnitude corresponding to the instructed speed, a speed detection circuit for detecting a speed on the basis of a signal from the speed detector and a microcomputer for driving the driver by comparing the speed instruction signal with a speed signal obtained from the speed detection circuit. The microcomputer includes a harmonic wave component detecting means for detecting a harmonic wave component contained in a speed variation mode which is obtained from the speed detection circuit and has a function of making the gain of a speed control system variable by the harmonic wave component detected by the harmonic wave component detecting means.

Speed control apparatus for movable equipment

A speed control apparatus is provided for controlling a speed of a movable equipment in such a way that the speed of the movable equipment is detected, calculates a deviation value between a detected speed of the movable equipment and a speed instruction signal, and controls the speed of the movable equipment based on the deviation value. The speed control equipment detects harmonic wave components included in the detected speed and reduces the harmonic wave components from the speed instruction signal so as to control the speed of the movable equipment.

Speed control apparatus of movable equipment

The stator comprises three phase driving coils and an electric commutator for controlling current to the driving coils. The rotor comprises permanent magnets which are alternately magnetized in N polarity and S polarity. Driving torque is generated corresponding to the current flowing through the driving coils and the permanent magnets. On the surface of the permanent magnet facing to the driving coils, two non-magnetizing portions are provided in each permanent magnet having either N or S polarity.

Low ripple-torque permanent magnet brushless motor

Disclosed is a speed controlling method and apparatus in which a suitable current or voltage command is given to a moving body on the basis of the relation between a speed detection signal obtained by detecting the speed of the moving body and an externally supplied speed command signal. The speed of the moving body is controlled in a manner so that the speed of the moving body is successively detected, a speed error which is a difference between a speed command value and a speed detection value is calculated whenever the speed of the moving body is detected, and the speed of the moving body is successively controlled on the basis of a driving signal obtained by an arithmetic operation on the basis of the speed error and a set control gain, and that, on the other hand, a present speed error quantity is calculated on the basis of speed errors obtained whenever the detection of the speed of the moving body have been carried out predetermined number of times, the speed error quantity obtained presently is compared with and the speed error quantity obtained last, and the set gain is corrected or updated in accordance with the result of comparison of the present and last speed error quantities to thereby minimize the speed error quantity.

Method and apparatus for controlling the speed of moving body

Growing community of inventors

Ibaraki, Japan

Seiichi Narushima