Motor control apparatus for synchronously controlling master axis and slave axis

• US 8,692,488 B2
• Filed: 09/14/2012
• Issued: 04/08/2014
• Est. Priority Date: 11/25/2011
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: Takayama, Kenichi, Kawamura, Hiroyuki
• Primary Examiner(s): Duda, Rina
• Application Number:
  US13/616,242
• Publication Number:
  US 20130134919A1
• Time in Patent Office: 571 Days
• Field of Search: 318/49, 318/51, 318/77, 318/85, 318/112
• US Class Current: 318/49
• CPC Class Codes: G05B 19/416 characterised by control of velocity, acceleration or deceleration G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/50218 Synchronize groups of axis, spindles

Abstract

A motor control apparatus for synchronously controlling a master axis motor for driving a master axis and a slave axis motor for driving a slave axis, includes: a master axis position detector which outputs position data of the master axis and a reference signal with a predetermined fixed period; a master axis receiving circuit which receives the position data and the reference signal output from the master axis position detector; a master axis computation circuit which computes a master axis error representing a difference between the position data received by the master axis receiving circuit and the position data acquired at the time of the reception of the reference signal; and a slave axis motor control unit which controls the operation of the slave axis motor by using the master axis error as a command for synchronizing the operation of the master axis motor.

Claims

1. A motor control apparatus for synchronously controlling a master axis motor for rotary-driving a master axis and a slave axis motor for rotary-driving a slave axis, comprising:

a master axis position detector which outputs position data, which is used to detect the rotational speed and rotational direction of said master axis, and a reference signal with a predetermined fixed period;

a master axis receiving circuit which receives said position data and said reference signal output from said master axis position detector;

a master axis computation circuit which computes a master axis error representing a difference between said position data received by said master axis receiving circuit and said position data acquired at the time of the reception of said reference signal;

a slave axis motor control unit which receives said master axis error and controls the operation of said slave axis motor by using at least said received master axis error as a command for synchronizing to the operation of said master axis motor; and

a master axis motor control unit which is connected to said master axis computation circuit, and which receives said master axis error from said master axis computation circuit and controls the operation of said master axis motor by using at least said received master axis error, while also transferring said master axis error to said slave axis motor control unit.

2. The motor control apparatus according to claim 1, wherein said reference signal from said master axis position detector is output in synchronism with said master axis position data.

3. The motor control apparatus according to claim 2, further comprising:

a slave axis position detector which outputs position data of said slave axis and a reference signal with a predetermined fixed period;

a slave axis receiving circuit which receives said position data and said reference signal output from said slave axis position detector; and

a slave axis computation circuit which computes a slave axis error representing a difference between said position data received by said slave axis receiving circuit and said position data acquired at the time of the reception of said reference signal, and wherein;

said slave axis motor control unit controls the operation of said slave axis motor so that the difference or ratio between said master axis error and said slave axis error is maintained constant.

4. The motor control apparatus according to claim 3, wherein said reference signal from said slave axis slave axis position data.

5. The motor control apparatus according to claim 1, further comprising;

a slave axis position detector which outputs position data of said slave axis and a reference signal with a predetermined fixed period;

a slave axis receiving circuit which receives said position data and said reference signal output from said slave axis position detector; and

a slave axis computation circuit which computes a slave axis error representing a difference between said position data received by said slave axis receiving circuit and said position data acquired at the time of the reception of said reference signal, and wherein;

said slave axis motor control unit controls the operation of said slave axis motor so that the difference or ratio between said master axis error and said slave axis error is maintained constant.

6. The motor control apparatus according to claim 5, wherein said reference signal from said slave axis position detector is output in synchronism with said slave axis position data.

7. The motor control apparatus according to claim 1, wherein at least one of said master axis computation circuit, said master axis motor control unit, and said slave axis motor control unit includes a correcting circuit which corrects said master axis error by using a data transmission delay time occurring between said master axis motor control unit and said slave axis motor control unit.

8. The motor control apparatus according to claim 1, wherein said master axis is an axis for driving a tool in a gear generating machine, and said slave axis is an axis for driving a workpiece in said generating machine.