JPH0482657A - Profile method - Google Patents

Abstract

PURPOSE:To perform indexing with the tolerance complied with the shape of a model, by deciding tolerance according to a profile speed and performing indexing whenever the movement quantity exceeds the tolerance, in the profile method profiling the surface of a model with a tracer head. CONSTITUTION:A tracer head 20 detects the displacement quantities epsilonx, epsilony and epsilonz caused by its contact with the model of a stylus 21, and inputs them to a changeover circuit 1 and synthetic circuit 3. In the changeover circuit 1, the commanded biaxial displacement quantities epsilon1, epsilon2 of a profile plane are indexed and input to an indexing circuit 2 with the selection, and the circuit 2 finds indexing signal Ec and Es. In a synthetic circuit 3, a synthetic displacement quantity epsilon is input to a computing element 4 with its finding from each displacement quantity epsilonx, epsilony and epsilonz, the computing element 4 inputs the finite difference epsilon in the synthetic displacement quantity epsilon and reference displacement quantity epsilon0 to speed signal generating circuits 5 and 6 with its operation. The speed signal generating circuit 5 generates a feed speed signal Vt in the orthogonal direction with a stylus displacement direction, and the speed signal generating circuit 6 generates a feed speed signal Vn in the stylus displacement direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for tracing the surface of a model, and more particularly to a tracing method with improved indexing.

[Conventional technology]

In the normal tracing method, the surface of the model is traced with a tracer head, the amount of displacement is detected, and a tracing speed is generated according to the displacement error between the amount of displacement and the reference displacement amount to perform tracing processing.

Further, the moving direction of the tracer head is determined by the amount of displacement for each fixed tolerance (moving distance). This is called indexing. This determination is made by the microprocessor of the profile controller. Generally, the tracing speed is fast in flat areas of the model, and slow in sudden changes.

[Problem to be solved by the invention]

However, this tolerance is the same whether the surface of the model is flat or where there are sudden changes. That is, it is constant regardless of the tracing speed.

Therefore, in a flat place, that is, a place where the tracing speed is fast, the tracing direction hardly changes, so a detailed indexing operation is not necessary.

On the other hand, in areas where the model suddenly changes, that is, where the tracing speed is slow, the tracing direction constantly changes, so detailed determination is required.

Therefore, in the conventional indexing method, there is a problem that unnecessary indexing is performed in flat parts of the model, and indexing is too coarse in parts of the model that suddenly change.

The present invention has been made in view of these points, and it is an object of the present invention to provide a tracing method that performs indexing with a tolerance depending on the shape of the model.

[Means to solve the problem]

In order to solve the above problems, the present invention is characterized in that, in a method of tracing the surface of a model with a tracer head, a tolerance is determined according to the tracing speed, and an index is performed each time the amount of movement exceeds the tolerance. A method for tracing is provided.

[Effect]

The tracing speed is fast in flat parts of the model, and slow in sudden changes. Therefore, the tolerance should be increased in locations where the tracing speed is fast, and the tolerance should be decreased in locations where the tracing speed is slow. Calculation is performed each time this tolerance amount is exceeded.

This allows for coarse indexing in flat areas of the model, and finer indexing in abruptly changing areas.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 is a block diagram showing the configuration of a profiling control device for implementing the present invention. In the figure, a tracer head 20 installed in a profiling machine tool detects displacements εX1εy and εZ in the X-axis, Y-axis, and Z-axis directions caused by the stylus 21 at its tip coming into contact with the model. It is input to the switching circuit 1 and the combining circuit 3. The switching circuit 1 selects the operation panel 30 from among these displacement amounts.
Biaxial displacements ε1, ε of the tracing plane commanded via
2 is selected and input to the indexing circuit 2.

The indexing circuit 2 uses the displacement amounts εl and ε2 to form the following equation: Ec=ε1/(ε12+ε22) I72ose Es=e2/(ε12+ε2”)”2=sine are calculated to obtain index signals Ec and Es.

In addition, in the synthesis circuit 3, the composite displacement amount ε (ε=(ε12+ε2 +εz2)l/
2) is determined and input to the calculator 4. The calculator 4 calculates the difference Δε (
△ε=ε−εO) and speed signal generation circuits 5 and 6
Enter. The speed signal generation circuit 5 generates a feed speed signal (
A tangential velocity signal) Vt is generated. Further, the speed signal generation circuit 6 generates a feed speed signal (normal direction speed signal) Vn in the stylus displacement direction in proportion to the difference Δε.

The distribution circuit 7 uses the indexing signals Ec and Es, the tangential velocity signal Vt, and the normal velocity signal Vn to form the following equation: V1=VtXs 1ne-VnXcoseV2=-Vt
Xcose-Vn
Output as Vy and VZ, servo amplifier 9X, 9y
and amplified by 9z.

Then, the servo motors 22x and 22y are driven by the outputs of the servo amplifiers 9x and 9y, and a table (not shown) is moved. Further, the servo motor 22Z is driven by the output of the servo amplifier 9Z, and a cutter (not shown) moves in the Z-axis direction together with the tracer head 20.

FIG. 3 is a diagram showing details of the profile speed. here,
Tracing is performed on the Xz plane. Stylus 21 follows model 31. The tangential velocity Vt and the normal velocity Vn are obtained according to the error displacement amount εd (not shown), which is the difference between the composite displacement amount ε detected by the stylus 21 and the reference displacement amount εO (not shown). , the composite of these becomes the tracing speed V. Here, the tracing speed V is the X axis,
They are distributed along the Z-axis to find Vx and Vz, respectively.

Next, indexing will be explained. FIG. 1 is a flowchart of one embodiment of the indexing of the present invention.

In the figure, the number following S indicates the step number.

[S1] Calculate the moving distance Lxy on the χY plane.

[S2] Calculate the Z-axis movement distance Lz.

[S3] Find the tolerance T from T-(V/K). Here, ■ is the tracing speed, and K is a constant. That is, where the tracing speed is high, the tolerance is large, that is, the indexing is coarse.

On the other hand, in places where the tracing speed is slow, the indexing becomes finer,
Improves accuracy of tracing.

[34] Determine whether the moving distance Lxy in the XY plane exceeds the tolerance T. If it does, proceed to S6; if not, proceed to S5.

[:S5] Determine whether the Z-axis movement distance Lz exceeds the tolerance, and if so, proceed to S6.

[S6] Since the moving distance Lxy or the moving distance Lz exceeds the tolerance T, indexing processing is performed and the direction of the stylus 21 is changed.

In this way, the tolerance is changed according to the tracing speed, and the calculation is performed every time the moving distance exceeds the tolerance. As a result, the indexing becomes rough in areas where the tracing speed is high, that is, in flat areas of the model. On the other hand, in places where the tracing speed is slow, that is, in areas where the model changes suddenly, the indexing is performed more precisely, improving tracing accuracy.

In the above description, the tracing control device has been described, but the present invention can also be applied to digitizing that traces a model and collects surface data of the model.

〔Effect of the invention〕

As explained above, in the present invention, the tolerance for indexing is changed according to the speed, so the indexing becomes coarse in flat parts of the model, eliminating unnecessary indexing and reducing the processing burden on the processor, etc. Reduced.

In addition, the indexing becomes finer in areas where the model suddenly changes, improving tracing accuracy.

index circuit tracer head stylus model

Claims (4)

[Claims] (1) A tracing method for tracing the surface of a model with a tracer head, characterized in that a tolerance is determined according to the tracing speed, and an index is performed every time the amount of movement exceeds the tolerance. (2) The tracing method according to claim 1, wherein the amount of movement is divided into the amount of movement in the Z-axis direction and the amount of movement on the XY plane, and the indexing is performed even when either amount of movement exceeds the tolerance amount. . (3) The tracing method according to claim 1, wherein the tolerance is determined as follows: T=V/K, where T is the tolerance and V is the tracing speed. (4) The tracing method according to claim 1, wherein numerical data of the model is collected by said tracing.