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US4916375A Expired / Lapsed US ⏱️ 0.0 years remaining

Servomotor control apparatus

Assignee: Fanuc Corp
•
Filing: 1987-12-11
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Granted: 1990-04-10
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Expires: 2007-12-11
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Abstract

Abstract The invention is a servomotor control apparatus for controlling the positioning of a movable element of an industrial robot or NC machine tool. An NC unit or a robot controller detects displacement from a movable element that is to be positioned, such as a table, forms a position command regarding a servomechanism, and has a correction circuit (A) which receives quadrant data (BLF) regarding a backlash correction command. When there is a quadrant reversal for each axis of the movable element, frictional torque corresponding to the axis is stored and a torque correction command (FR) corresponding thereto is outputted. A torque command of a fully-closed loop servo system for performing control based on a fed back position detection signal is corrected by the torque correction command. The servomotor control apparatus can be applied to semi-closed loop servo system in which a backlash correction is possible, and not just to a fully-closed loop servo system.

Inventors

  • 👤 Mitsuo Kurakake
  • 👤 Keiji Sakamoto

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 19:35
CPC Classifications
G; G05; G05D; G05D3/00; G05D3/12; G05D17/00; G05D17/02; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/404; G05B2219/00; G05B2219/30; G05B2219/41; G05B2219/41036; G05B2219/41084; G05B2219/41426

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 117 words
A servomotor control apparatus for controlling movement of a mechanical load in response to a position command and to a backlash correction command for correcting backlash at the mechanical load, comprising: position detecting means for detecting a position of the mechanical load; discriminating means for discriminating, based on the backlash correction command, a time at which an operating quadrant of the mechanical load reverses; correcting means for receiving offset data corresponding to frictional resistance of the mechanical load, and for generating a corrected torque command based on the offset data, the detected position and the position command when the quadrant reverses; and control means for driving and controlling the mechanical load based on the corrected torque command.
Claim 2
Dependent Claim 117 words
A servomotor control apparatus for controlling movement of a mechanical load in response to a position command and to a backlash correction command for correcting backlash at the mechanical load, comprising: position detecting means for detecting a position of the mechanical load; discriminating means for discriminating, based on the backlash correction command, a time at which an operating quadrant of the mechanical load reverses; correcting means for receiving offset data corresponding to frictional resistance of the mechanical load, and for generating a corrected torque command based on the offset data, the detected position and the position command when the quadrant reverses; and control means for driving and controlling the mechanical load based on the corrected torque command.
Claim 3
Dependent Claim 19 words
A servomotor control apparatus according to claim 1, wherein said position signal detecting means comprises an optical linear scale.
Claim 4
Dependent Claim 32 words
A servomotor control apparatus according to claim 1, wherein said correcting means comprises means for storeing the offset data corresponding to a frictional resistance value for each axis of the mechanical load.
Claim 5
Dependent Claim 49 words
A servomotor control apparatus according to claim 1, wherein said control means comprises either a semi-closed loop servo system or a fully-closed loop servo system, and the corresponding means comprises a means for generating a corrected torque command based on the backlash correction command or on the offset data.
Claim 6
Dependent Claim 26 words
A servomotor Control apparatus according to claim 1, wherein the mechanical load is a machine tool or an industrial robot having a plurality of servo systems.
Claim 7
Dependent Claim 40 words
A servomotor control apparatus according to claim 1, wherein said discriminating means includes: means for determining, based upon the backlash correction command, a time at which a quadrant in the velocity-torque characteristic for an axis of the mechanical load reserves.

References Cited (Backward Citations)

US4196380A Cited
US4743822A Cited
US4792738A Cited
US4743823A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1993-04-09 1993-10-09 1994-04-10 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1997-04-09 1997-10-09 1998-04-10 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2001-04-09 2001-10-09 2002-04-10 $7700.00 Window Closed / Lapsed

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