Synchronizing control apparatus

• US 5,175,680 A
• Filed: 03/02/1990
• Issued: 12/29/1992
• Est. Priority Date: 03/02/1989
• Status: Expired due to Term

• Current Assignee: Toyoda Koki Kabushiki Kaisha
• Original Assignee: Toyoda Koki Kabushiki Kaisha
• Inventors: Yonezu, Toshihiro, Yoneda, Takao
• Primary Examiner(s): Smith, Jerry
• Assistant Examiner(s): Brown, Thomas E.
• Application Number:
  US07/487,449
• Time in Patent Office: 1,033 Days
• Field of Search: 364/474.11, 364/474.16, 364/474.19, 364/474.34, 364/474.35, 364/474.12, 364/176, 364/177, 318/563, 318/565, 318/567, 318/569, 318/632, 318/625, 318/85, 318/611, 318/615-617, 318/571, 318/675
• US Class Current: 700/71
• CPC Class Codes: G05B 19/182 characterised by the machine tool function, e.g. thread cutting, cam making, tool direction control G05B19/21 - G05B19/40 take precedence
• CPC Class Codes: G05B 2219/49252 Two spindle drives for common workpiece
• CPC Class Codes: G05B 2219/50234 Synchronize two spindles, axis, electronic transmission, line shafting

Abstract

A synchronizing control apparatus for synchronously rotating master and slave main spindles of a pin grinder, wherein a servomotor for the slave main spindle is rotated at a speed corresponding to a compensated command value while the master main spindle is rotated at a speed corresponding to a noncompensated command value. The compensated command value is calculated based on a synchronizing error between the master and slave main spindles at a predetermined interval longer than the length of instable condition of a servo loop for the slave main spindle. When the synchronizing error is larger than a predetermined limit value, the command value for the slave main spindle is gradually compensated in order to prevent the compensated command value from changing too abruptly.

Claims

1. A synchronizing control apparatus for synchronously controlling a first rotary spindle engaged with one end of a rotary member and a second rotary spindle engaged with the other end of said rotary member, said synchronizing control apparatus comprising:

a pair of servomotors for driving said two spindles, respectively;

a pair of drive circuit means for driving said pair of servomotors in accordance with a command value;

synchronizing error detecting means for detecting a synchronizing error based upon an angular position difference between said two rotary spindles;

comparing means for comparing said detected synchronizing error with a predetermined limit value;

limiting means for regarding said synchronizing error as a compensation adding value when said synchronizing error is smaller than said predetermined limit value and for regarding said limit value as said compensation adding value when said synchronizing error is larger than said limit value;

compensation value calculating means for adding said compensation adding value to a previous compensated command value in order to obtain a new compensated command value; and

control means for outputting said command value to one of said drive circuit means and for outputting said compensated command value to the other of said drive circuit means.

2. A synchronizing control apparatus set forth in claim 1, wherein said synchronizing error detecting means comprises:

a pair of angular position sensors for detecting angular position of said two spindles; and

calculation means for calculating a difference between the angular position detected by said angular position sensors.

3. A synchronizing control apparatus set forth in claim 2, wherein said comparing means further comprises limit value setting means for inputting and storing said limit value.

4. A synchronizing control apparatus set forth in claim 1, wherein said synchronizing error detecting means, said comparing means, said limiting means, compensation value calculating means and said control means operate at a predetermined time interval larger than a time length of instable condition of said other drive circuit means.

5. A method for synchronously rotating two rotary spindles by a pair of servomotors to rotate a common member at a predetermined speed, wherein said method comprises steps of:

outputting a pair of command values corresponding to said predetermined speed to a pair of drive circuits driving said pair of servomotors, respectively;

detecting a synchronizing error based upon an angular position difference between said two rotary spindles;

comparing said detected synchronizing error with a predetermined limit value;

regarding said synchronizing error as a compensation adding value when said synchronizing error is smaller than said predetermined limit value and regarding said limit value as said compensation adding value when said synchronizing error is larger than said limit value;

adding said adding compensation value to said command value output to one of said drive circuits; and

repeating said detecting step through said adding step at a predetermined time interval.

6. A method for synchronously rotating two rotary spindles set forth in claim 5, wherein said steps are repeated at a predetermined time interval larger than a time length of instable condition of said one of drive circuits.

7. A synchronizing control apparatus for synchronously controlling a master main spindle and a slave main spindle of a pin grinder, wherein said master main spindle is engaged with one end of a workpiece and said slave main spindle is engaged with the other end of said workpiece to rotate said workpiece, said synchronizing control apparatus comprising:

a pair of servomotors for driving said master main spindle and said slave main spindle, respectively;

a pair of angular position sensors for detecting angular positions of said master main spindle and said slave main spindle, respectively;

a pair of drive circuit means for driving said pair of servomotors in accordance with a command value;

synchronizing error detecting means for detecting a synchronizing error of said slave main spindle with respect to said master main spindle based upon angular positions of said master and slave main spindles detected by said pair of angular position sensors;

comparing means for comparing the detected synchronizing error with a predetermined limit value;

limiting means for regarding said synchronizing error as a compensation adding value when said synchronizing error is smaller than said predetermined limit value and for regarding said limit value as said compensation adding value when said synchronizing error is larger than said limit value;

compensation value calculating means for adding said compensation adding value to a previous compensated command value in order to obtain a new compensated command value; and

outputting means for outputting said command value to one of said drive circuit means and for outputting said compensated command value to the other of said drive circuit means;

wherein said control means includes means for renewing said compensated command value at a predetermined time interval larger than a time length of instable condition of said other drive circuit means.

8. A synchronizing control apparatus for synchronously controlling a master main spindle and a slave main spindle of a machine tool, wherein said master main spindle is engaged with one end of a workpiece and said slave main spindle is engaged with the other end of said workpiece to rotate said workpiece, said synchronizing control apparatus comprising:

a pair of servomotors for driving said master main spindle and said slave main spindle, respectively;

a pair of angular position sensors for detecting angular positions of said master main spindle and said slave main spindle, respectively;

a pair of drive circuit means for driving said pair of servomotors in accordance with a command value;

synchronizing error detecting-means for detecting a synchronizing error of said slave main spindle with respect to said master main spindle based upon angular positions of said master and slave main spindles detected by said pair of angular positions sensors;

comparing means for comparing the detected synchronizing error with a predetermined limit value;

limiting means for regarding said synchronizing error as a compensation adding value when said synchronizing error is smaller than said predetermined limit value and for regarding said limit value as said compensation adding value when said synchronizing error is larger than said limit value;

compensation value calculating means for adding said compensation adding value to a previous compensated command value in order to obtain a new compensated command value; and

outputting means for outputting said command value to one of said drive circuit means for outputting said compensated command value to the other of said drive circuit means,

wherein said control means includes means for renewing said compensated command value at a predetermined time interval larger than a time length of instable condition of said other drive circuit means.