Method of digitizing a profile locus

• US 4,746,251 A
• Filed: 01/23/1986
• Issued: 05/24/1988
• Est. Priority Date: 05/24/1985
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Inventors: Yoshikawa, Hirofumi, Matsunaga, Yuso
• Primary Examiner(s): BILINSKY, ZENON
• Application Number:
  US06/821,707
• Time in Patent Office: 852 Days
• Field of Search: 364/474, 364/520, 318/578, 409/84, 409/85, 409/116, 409/117, 409/125, 409/130, 409/99
• US Class Current: 409/84
• CPC Class Codes: B23Q 35/123 the feeler varying the impedance in a circuit
• CPC Class Codes: G05B 2219/50167 Adapting to copying
• CPC Class Codes: Y10T 409/30112 Process
• CPC Class Codes: Y10T 409/30196 to actuate electrically driven work or tool moving means

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.

Claims

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.

2. A method according to claim 1, wherein the rate of change of the shape of the model is determined by the relation

3. A method according to claim 1, wherein the rate of change of the shape of the model is determined by the relation

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:

(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.

5. A method according to claim 4, 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 a normal vector ε

of the displacement of the stylus increases, wherein

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.