Method of digitizing a profile locus
First Claim
1. In a profiling method for performing NC working on the basis of locus data obtained by profiling a shape of a model by a stylus in a profiling machine, a method of digitizing profile locus data comprising steps of:
- rounding position data of a surface of the model, obtained by adding a position signal of the profiling machine and a displacement signal from a tracer head, at each sampling time upon profiling operation by means of a low-pass filter having a changeable time constant; and
automatically changing the time constant of said filter in response to a rate of change of the shape of the model, wherein the time constant of said filter is decreased when the rate of change of the shape of the model increases.
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Abstract
In a profiling method constructed so that NC working is performed on the basis of profile locus data obtained by profiling a shape of a model by a profiling machine, a digitized method of the profile locus is characterized in that position data of the model surface, obtained by adding a position of the profiling machine and a displacement signal from a tracer head at each sampling time, are rounded through a low-pass filter upon a profiling operation, and a time constant of the filter is automatically changed in response to the rate of change of the shape of the model. According to this method, fluctuation of the profiling machine, which can not be corrected by the filter heretofore and is an error as it is, is corrected, and a stylus displacement signal, delayed as compared with a response of a profiling machine position signal upon high speed profiling operation, is greatly improved so that high speed profiling operation can be attained.
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Citations
5 Claims
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1. In a profiling method for performing NC working on the basis of locus data obtained by profiling a shape of a model by a stylus in a profiling machine, a method of digitizing profile locus data comprising steps of:
- rounding position data of a surface of the model, obtained by adding a position signal of the profiling machine and a displacement signal from a tracer head, at each sampling time upon profiling operation by means of a low-pass filter having a changeable time constant; and
automatically changing the time constant of said filter in response to a rate of change of the shape of the model, wherein the time constant of said filter is decreased when the rate of change of the shape of the model increases. - View Dependent Claims (2, 3)
- 3. A method according to claim 1, wherein the rate of change of the shape of the model is determined by the relation
- space="preserve" listing-type="equation">K=|ε
| and
space="preserve" listing-type="equation">ε
=√
ε
.sub.x.sup.2 +ε
.sub.y.sup.2 +ε
.sub.z.sup.2,in which K is the rate of change, and (ε
x, ε
y, ε
z) is the displacement of the stylus, and ε
is a normal vector of the displacement. - space="preserve" listing-type="equation">K=|ε
- rounding position data of a surface of the model, obtained by adding a position signal of the profiling machine and a displacement signal from a tracer head, at each sampling time upon profiling operation by means of a low-pass filter having a changeable time constant; and
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4. In a profiling method for performing NC working on the basis of locus data obtained by profiling a shape of a model by a stylus of a profiling machine, a method of digitizing profiling locus data comprising the steps:
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(a) detecting displacement of the stylus by stylus detection means and generating digitized stylus detection signals (ε
x, ε
y, ε
z);(b) producing profiling speed command signals, for driving respective drive motors corresponding to three axes of the profiling machine in response to the stylus detection signals on the basis of central position signals of the stylus from a profiling data processing unit, by a profiling speed controlling unit; (c) detecting drive positions of the drive motors by position detection means to produce drive position signals; (d) adding the drive position signals (X, Y, Z,) for the three axes to the stylus detection signals (ε
x, ε
y, ε
z) of the stylus displacement detecting means by an arithmetic operation unit for a central position of the stylus, to produce profiling data signal; and(e) passing the profiling data signal through an electric filter in the profiling data processing unit to apply a time constant, defined by a rate of change of the displacement (ε
x, ε
y, ε
z) of the stylus according to the relation K=|ε
x |+|ε
y |+|ε
z |, in which K is the rate of change, to the profiling data signal, wherein the time constant of the electric filter in the profiling data processing unit is automatically made smaller as the rate of change K of the displacement of the stylus increases, and producing the central position signal of the stylus to the profiling speed controlling unit. - View Dependent Claims (5)
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Specification