Boots – shoes – and leggings
Patent
1988-10-27
1990-09-18
MacDonald, Allen
Boots, shoes, and leggings
3644742, G05B 1900
Patent
active
049582933
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a digitizing method in which contactor position data is accepted while tracer control is being performed. More particularly, the method relates to a digitizing method in which it is possible to accept position data conforming to a profile even if there is bite-in at a corner portion or the like.
2. Description of the Related Art
A digitizer is available in which a contactor is moved along a model by tracer control, the present position of the contactor is monitored and the three-dimensional shape of the model is digitized by accepting contactor position data at a predetermined time interval.
If the contactor is a tracer head equipped with a stylus in this method of digitizing a three-dimensional shape by tracer control, the stylus is moved along the model without biting into the model. However, the motion of the tracer head holding the stylus is similar to the dotted line in FIG. 4, and the points indicated by the large dots are digitized as the path of the contactor ST. Consequently, when NC data is created using these digitized points and machining is performed in accordance with this NC data, a problem that arises is that bite-in occurs at the corner so that machining conforming to the shape of the model cannot be carried out.
Accordingly, an object of the invention is to provide a digitizing method that enables digitizing conforming to the shape of a model even if the contactor bites into the model at a corner or the like at the time of digitizing.
SUMMARY OF THE INVENTION
The invention relates to a digitizing method for moving a contactor along a model on the basis of tracer control and digitizing probe position data upon accepting the data as a predetermined reference. In this digitizing method, when three points most recently accepted are P.sub.1, P.sub.2 and P.sub.3 in the order of acceptance, the point P.sub.2 is not digitized if an angle .theta. defined by a vector P.sub.1 P.sub.2 and a vector P.sub.2 P.sub.3 is larger than a predetermined angle .theta..sub.max.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1(a) and 1(b) are views for describing the general features of the method of the present invention;
FIG. 2 is a block diagram of an apparatus (a digitizer) for executing digitizing processing according to the invention;
FIG. 3 is a flowchart of processing according to the invention;
FIG. 4 is a view for describing bite-in; and
FIG. 5 is a block diagram illustrating a system for controlling a machine tool using digitized position data.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1(a) and 1(b) is a view for describing the general features of the method of the present invention.
P.sub.1, P.sub.2, P.sub.3 represent three machine positions most recently accepted, .theta. denotes an angle defined by a vector P.sub.1 P.sub.2 and a vector P.sub.2 P.sub.3, and .theta..sub.MAX represents a maximum allowable angle.
Thus, let the three points most recently accepted be P.sub.1, P.sub.2 and P.sub.3 in the order of acceptance. The angle .theta. defined by the vector P.sub.1 P.sub.2 and the vector P.sub.2 P.sub.3 is computed, the point P.sub.2 [FIG. 1(b)] is not digitized when .theta. is greater than the predetermined angle .theta..sub.MAX. When .theta. is less than the predetermined angle .theta..sub.MAX, on the other hand, all three of the points P.sub.1, P.sub.2 and P.sub.3 [FIG. 1(a)] are digitized.
FIG. 2 is a block diagram of an apparatus (a digitizer) for executing digitizing processing according to the invention.
In FIG. 2, numeral 1 denotes a digitizer equipped with a digitizing function for accepting the present position of a tracer head while tracer control is being formed, as will be described below. The digitizer 1 has a processor 1a, a ROM 1b storing a control program, a RAM 1c for storing digitized data, and a working memory 1d.
Numeral 2 denotes an operator's panel having functions for inputting various operation signals and setting tracing conditions, tracing areas, tracing method and the like.
Numerals 10X,
REFERENCES:
patent: 4550383 (1985-10-01), Sugimoto
patent: 4648024 (1987-03-01), Kato et al.
patent: 4841430 (1989-06-01), Nakagawa et al.
Itsubo Yoshihiro
Onishi Yasushi
Tanaka Kunio
Fanuc Ltd.
MacDonald Allen
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