US 2010/0109594 A1Published application

Position control apparatus for numerically controlled machine

AssigneeOkuma Corporation

InventorMasashi Miyaji

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Abstract

In a position control apparatus that drives a feed-axis with a servomotor of a machine tool, the machine tool maybe quickly accelerated or decelerated in a state where a machine structural member that supports and fixes a structural member including a driving system has a lower rigidity, or in a state where an element having a lower rigidity is present beyond a load position where the detection by a linear scale is performed. In such cases, a generated deflection may induce a displacement in a mechanical system. A relative locus error may be generated between a workpiece to be processed and a front end portion of the tool. Further, a mechanism rigidity generally changes according to a machine posture. The generated deflection amount changes in magnitude. The present embodiment estimates and compensates a displacement amount of the front end portion of the tool that may be caused by the deflection of the mechanical system. Moreover, in calculating an estimation amount, the present embodiment can change a parameter corresponding to the mechanism rigidity based on the machine posture. Thus, the front end of the tool can move accurately along a desired locus relative to the workpiece to be processed.

Claims7

Dependent claims

A position control apparatus that is usable in a case where a motor drives a movable portion of a numerically controlled machine to change a relative positional relationship between two control objects provided on the numerically controlled machine, wherein the position control apparatus controls the position of the movable portion based on a position command value of the motor that is input from a host apparatus, the position control apparatus comprising:

a machine deflection amount estimation unit that calculates a machine deflection amount estimation value representing a relative displacement amount between the two control objects that may be caused by a deflection of a structural member intervening between the two control objects based on information indicating a posture of the intervening structural member and information indicating a driving acceleration of the movable portion;
a machine deflection compensation amount calculation unit that calculates a machine deflection position compensation value based on the machine deflection amount estimation value for compensating at least a positional deviation that may be caused by a deflection of the intervening structural member;
and
a command value calculation unit that generates a new position command value for the control by adding the machine deflection position compensation value to the position command value.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 12/581,569Filed 19 Oct 2009
Priority: JP 2008-28208131 Oct 2008
Published: 6 May 2010
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G05B 19/404
Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to…
G05B 19/19
Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to…
G05B 2219/41403
Servomotor, servo controller till figures: machine deformation estimator as function of commanded position
G05B
Control or regulating systems in general