US 5,396,434 AGranted

Machining-error correcting method used for a non-circular shape machining apparatus

AssigneeOkuma Corporation

InventorsHiroshi Oyama, Kenji Ito

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Abstract

A machining-error of a non-circular shape machining apparatus is corrected by controlling a movement of a tool which is synchronous with a rotation of a workpiece. A position of the tool is detected when the tool is according to a command position which is coincident with or close to a target position of the tool. At least an amplitude ratio and a phase difference of an amplitude ratio, a phase difference, and an offset difference between the target position and the detected position; is obtained. At least a process of increases and/or reducing the command position and a process of phase shift of the process for increasing and/or reducing the command position on the basis of the amplitude ratio, a process for shifting a phase on the basis of the phase difference, and a process for changing an offset of the command position on the basis of the offset difference are performed, whereby a first corrected command position is obtained. The detected position of the tool can be made to coincide with the target position quickly since the target position and the detected position are determined as a waveform, which is divided into an amplitude, a phase, an offset and a distorsion.

Claims7

Dependent claims

In a process for correcting a machining-error of a non-circular shape machining apparatus by controlling a movement of a tool which is synchronous with a rotation of a workpiece, a machining-error correcting method used for said non-circular shape machining apparatus, comprising the steps of:

detecting a position of said tool relative to a rotational axis of said workpiece while said tool is alternately and repeatedly moved toward and away from the rotational axis of said workpiece according to a command position which is coincident with or close to a target position of said tool to obtain a detected position;
obtaining an amplitude ratio, a phase difference, and an offset difference between said target position and said detected position;
performing a process of changing an amplitude of said command position on the basis of said amplitude ratio, a process of shifting a phase of said command position on the basis of said phase difference, and a process of changing an offset of said command position on the basis of said offset difference, whereby a first corrected command position is obtained;
performing a process of changing an amplitude of said detected position on the basis of said amplitude ratio, a process of shifting a phase of said detected position on the basis of said phase difference, and a process of changing an offset of said detected position on the basis of said offset difference, whereby a predicted detected-position is obtained;
and
performing a process of obtaining a difference between said target position and said predicted detected-position as a predicted error, and a process of correcting said first corrected command position by said predicted error to obtain a second corrected command position.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/996,402Filed 23 Dec 1992
Priority: JP 3-35732525 Dec 1991
Granted: 7 Mar 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G05B 19/184
Characterised by the machine tool function, e.g. thread cutting, cam making, tool direction control: generation of cam-like surfaces
G05B 2219/41374
Servomotor, servo controller till figures: observe position and driving signal, predict, estimate disturbance signal
G05B 2219/45218
Nc applications: making cams, cones
G05B 2219/50053
Machine tool, machine tool null till machine tool work handling: machine non circular, non-round cross section, hexagonal, rectangular