公开(公告)号：US10712153B2

公开(公告)日：2020-07-14

申请号：US15477691

申请日：2017-04-03

Applicant: TOPCON CORPORATION

Inventor： Kaoru Kumagai ,  Satoshi Yanobe ,  Tetsutaro Kouji

IPC: G01C15/00 ,  H02N2/14 ,  G01C15/02 ,  G05B7/00 ,  H02N2/00 ,  H02N2/16

Abstract: Provided is a method for controlling an ultrasonic motor to reduce deterioration of automatic tracking performance, and a surveying instrument for the same. The present invention provides a method for controlling an ultrasonic motor in a surveying instrument including a rotary shaft, an ultrasonic motor that drives a rotary shaft, a tracking unit that includes a light emitting unit and a light receiving unit and tracks a target, and a clock signal oscillation unit that outputs a clock signal, wherein at the time of low-speed rotation of the ultrasonic motor, based on the clock signal, a ratio of an acceleration period in which a drive signal is applied and a deceleration period in which the drive signal is stopped in a drive cycle of the drive signal of the ultrasonic motor is set, and the light emitting unit is made to emit light in the deceleration period.

公开(公告)号：US10211387B2

公开(公告)日：2019-02-19

申请号：US15463920

申请日：2017-03-20

Applicant: TOPCON CORPORATION

Inventor： Kaoru Kumagai ,  Satoshi Yanobe ,  Tetsutaro Kouji

IPC: H02P23/20 ,  H01L41/04 ,  B06B1/06 ,  G01C3/08 ,  G01D5/347 ,  G01S3/786 ,  H01L41/09 ,  G01C15/00 ,  H02N2/14 ,  H02N2/16

Abstract: Provided is a method for controlling an ultrasonic motor to reduce noise sounding during low-speed rotation in a surveying instrument adopting the ultrasonic motor for a rotary shaft, and a surveying instrument for the same. In a method for controlling an ultrasonic motor according to an aspect of the present invention, in a low-speed rotation range of an ultrasonic motor, a ratio of an acceleration period as a time of application of the drive signal in a control cycle is controlled, and a time to start the acceleration period is randomly shifted for each control cycle. In a method for controlling an ultrasonic motor according to another aspect, a time to start the acceleration period is regularly shifted for each control cycle. In a method for controlling an ultrasonic motor according to still another aspect, second-half acceleration control and first-half acceleration control are alternately repeated.