EP0420985A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Involute interpolation speed control system

Assignee: Fanuc Corp

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Filing: 1990-01-10

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Granted: —

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Expires: 2010-01-10

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Abstract

Abstract This invention relates to an involute interpolation speed control system for making involute interpolation by applying tool correction for machining in a numerical controller or the like. The system instructs a rotating direction of a first involute curve (In1) as an actual machining shape, the coordinates (Pee) of an end point, the center position of a basic circle (C) as viewed from a start point (Pss), the radius (R) of the basic circle (C), a feed speed, a tool diameter offset direction and the radius of the tool (Rofs). An offset vector of the tool is generated from this instruction and an equation of a second involute curve (In2) connecting its start point (Ps) and its end point (Pe) is calculated. The radius of curvature of the second involute curve (In2) is determined and a feed speed override value is determined from the tool offset direction and the radius of curvature. The second involute curve (In2) is interpolated by the speed as the product of the feed speed and the feed speed override value. This interpolation is made so that the cutting speed (Fp) in the tangential direction of the outer periphery of the tool generating the actual machining shape becomes constant.

Inventors

👤 Takao Sasaki
👤 Kunihiko Murakami
👤 Masafumi Fanuc Dai-3 Vira-Karamatsu Sano

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-10-30 20:13

CPC Classifications

G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/41; G05B19/4103; G05B2219/00; G05B2219/30; G05B2219/34; G05B2219/34144; G05B2219/43; G05B2219/43141; G05B2219/50; G05B2219/50336

Claims Analysis

Total Claims: 4

Claim 1

Independent Claim 201 words

An involute interpolation speed control system for effecting an involute interpolation to which a cutter compensation is applied when machining by a numerical control apparatus and the like, comprising the steps of: outputting commands for a direction in which a first involute curve as an actual machining configuration is rotated, coordinates of the end point of the first involute curve, a position of a center of a basic circle as viewed from a start point of the first involute curve, a radius of the basic circle, a feed speed, a direction in which a cutter is offset, an amount of offset of the cutter; creating an offset vector of said cutter based on the commands; calculating an equation of a second involute curve connecting a start point and an end point after the the offset vector has been created; determining a radius of curvature of the second involute curve at a center of said cutter; determining a feed speed override value based on said direction in which said cutter is offset, said offset amount, and said radius of curvature; and interpolating said second involute curve based on a value obtained by multiplying said feed speed override value by said feed speed.

Claim 2

Dependent Claim 123 words

An involute interpolation speed control system according to claim 1, wherein the second involute curve is calculated by the steps of: determining the coordinates (X₀, Y₀) of the center of the basic circle of the second involute curve, the angle (ϑ2) of the start point thereof, the angle (ϑ3) of the end point thereof, and the curve start angle (ϑ1) thereof based on the commands and the coordinates of the start point of the second involute curve; obtaining the coordinates of a point on the second involute curve from the following equations based on the thus determined values; X = R{cos(ϑ + ϑ1) + ϑsin(ϑ + ϑ 1)} + X₀ Y = R {sin(ϑ + ϑ1) - ϑ cos(ϑ + ϑ1)} + Y₀

Claim 3

Dependent Claim 155 words

An involute interpolation speed control system according to claim 2 wherein, when the cutter is positioned on the concave side of the first commanded involute curve, the feed speed override value V is determined by; V = (Rtan + Rofs)/Rtan (Rtan: the radius of curvature of said second involute curve, Rofs: said offset amount), and when the cutter is positioned on the convex side of the first commanded involute curve, the feed speed override value V is determined by; V = (Rtan - Rofs)/Rtan and wherein ϑ is incremented based on the following equation in the range of from ϑ = (ϑ2 - ϑ1) to ϑ = (ϑ3 - ϑ1); ϑ n+1 = ϑ n + V · K/(R · ϑ) and, a point X n+1 , Y n+1 corresponding thereto is determined from the above equations to obtain a difference between the previous point and this point, whereby said second involute curve is interpolated.

Claim 4

Dependent Claim 80 words

An involute interpolation speed control system according to claim 3, wherein when said cutter is positioned on the concave side of said first commanded involute curve, a maximum acceleration ratio Vmax is set, when said cutter is positioned on the convex side thereof, a minimum acceleration ratio Vmin is set, and said feed speed override value is clamped using said maximum acceleration ratio Vmax as an upper limit value and said minimum acceleration ratio Vmin as a lower limit value.

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