The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 29, 2003
Filed:
Jul. 11, 2001
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
In a stepping motor control method using an encoder, a timer means is provided, and an excessive advance of a phase during low rotation is restricted to attain a high speed without compromising stability during low rotation by driving the motor in such a manner that a pre-reversal state is recovered a predetermined time after a voltage reversal and a post-reversal state is recovered after one cycle of an angle detecting means. A device is provided which controls a speed by a pulse generator generating pulses at predetermined intervals, which detects a sudden drop in speed from a predetermined time elapsed from the last pulse, and which detects, when a speed is to be recovered, an abnormal drop in motor rotation independent of the motor rotation speed by changing a threshold value of an elapsed time according to an actual speed, a speed command value and an acceleration command value. A device is provided which controls deceleration by switching from a close-loop control to microstep driving in deceleration, wherein a drive amplitude in microstep drive into a predetermined relation with a drive amplitude in closed-loop control so that unnecessary vibration when switching to microstep driving is prevented while out-of-step is prevented.