JPH01109056A - Copy control method - Google Patents

Abstract

PURPOSE:To bring trace error to zero regardless of inclination angle and to achieve an accurate copy control by measuring the distance to the surface of a model every time then obtaining an inclination angle of the model based on a difference of measured distances and making follow-up control. CONSTITUTION:CPU1 carries out detection of relative positions in the direction of X-Z axes between a distance meter 10 being driven by servo motors 9x-9z and a model 13 on a table 12 through position detectors 15x-15z and counters 7x-7z every predetermined time set by a timer 2. Then inclination angle of the model 13 is obtained based on every relative moving amount and variation of distance to the model 13 measured through the distance meter 10, and follow-up control is made accordingly. Since trace error is brought to zero regardless of the inclination angle, accurate copy control can be made.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method of controlling a pattern using a non-contact distance measuring device such as a laser distance measuring device, and particularly relates to a method of controlling the distance to a model surface and a machine position. This invention relates to a tracing control method for tracking a model surface by determining the angle of inclination of the model surface.

[Conventional technology]

A tracing control method that irradiates the model surface with a laser beam, detects the reflected light, detects the distance to the model surface, and performs tracing control while keeping the distance to the model surface constant. be.

Specifically, from the distance to the model surface, the reference path m t
Find the deviation (L-L6) by subtracting @, multiply this value by the loop gain K, set it as the corrected speed, set this corrected speed as the Z-axis output speed, set the command speed Vc as the X-axis output speed, and set the model. Track the surface. The speed of each axis is as follows.

Vx-Vc (1) Vz = K
(L-L6) (2) This control method is controlled regardless of the inclination angle of the model surface.

[Problem that the invention seeks to solve]

However, in the conventional method, the following relationship holds true.

Vz/Vxxtanα (3) Vz=Vx−tanα (4) In equation (4), (
2) Substituting the formula, K (LLLo) = Vx -tanot Therefore, L-Lo = (Vx/K) ・tarzr (5
), and equation (5) shows that the tracking error of the profile is proportional to the tangent of the inclination angle α, and the problem is that the tracking error changes depending on the inclination angle of the model surface, making it impossible to perform accurate profile control.

An object of the present invention is to solve the above problems, to track the model surface by determining the distance to the model surface and the inclination angle of the model surface from the machine position, and to track the model surface so that the tracking error is independent of the model inclination angle. The objective is to provide a control method.

[Means for solving problems]

In order to solve the above problems, the present invention provides a tracing control method in which a machine having at least three axes of moving parts measures the distance to a model surface and performs tracing control. At the same time, measure the distance to Calculate the inclination angle α of the model in the plane formed by the reference axis and the Z axis from the following formula, αmarc tan ((ΔZ+ΔL)/ΔX) using the distance measurement data L and the preset reference road. #IL
, calculate the difference (L-L0) as a deviation, find the corrected speed component K (L-L0) from the deviation and the loop gain, and use the following formula from the tilt angle α and the corrected speed K (LL0), Calculate the speed of each axis, Vx-Vc-cos ex-K (L-Lo)
・sin exVzmVc -5in cx+K (L
A tracing control method is provided, comprising: tracking the model surface.

[Effect]

Substituting the feed rate VX%VZ of each axis above into the above-mentioned equation (4), Vz=Vx-tanα, we get Vc-sin α0K (L-Lo) ・cos
α=(Vc-cosα-K(L-L0) ・cosα
] ・tanα Therefore, L −Lo = V c Ccosa jtanα−5
incr)/K 1 = O (where K 1- (K/cos α)), the tracking error (L-L@) becomes independent of the inclination angle of the model, and accurate tracing control becomes possible.

〔Example〕

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

FIG. 1 shows a block diagram of an apparatus for carrying out the profiling control method of the present invention. In FIG. 0, 1 is a processor that controls the entire system, and 2 is a timer, which informs the processor 1 of the time. 3 is a memory, which includes a ROM in which a control program is stored, and R for storing various parameters, data, etc.
It consists of AM, etc. 4 is an input/output signal interface (110), which exchanges input/output signals with the outside. 5 is an AD converter, which converts an analog signal from a distance measuring device (described later) into a digital signal * 6
x% 6716z is the DA of Y axis, Y axis, Z゛ axis respectively
The converter converts the digital command value written from the processor 1 into an analog value and outputs the analog value. 7x, 7
y and 7z are Y-axis, Y-axis, and Z-axis counters, respectively, which are read by the processor 1 and reset by detecting a feedback pulse from a position detector, which will be described later.

8xs ays 8z are Y-axis, Y-axis, and Z-axis servo amplifiers, which receive analog signals from DA converters 6x16y and 6z, and servo motors 9'J-s9y,
Drive 9z.

IO is a distance measuring device, and here a laser distance measuring device is used, which reflects the laser light irradiated to the model, receives this reflected light, generates a voltage signal proportional to the distance, and calculates the voltage. The signal is output to the AD converter 5. Further, as the distance measuring device, an ultrasonic distance measuring device or the like can be used in addition to the laser distance measuring device. Reference numeral 11 denotes a column head on which a distance measuring device 1O is provided so that it can be moved up and down by a servo motor 9z. 12 is a table, on which a model 13 is fixed. The movement of the table 12 is controlled by servo motors 9X and 9y. Reference numeral 14 denotes a control panel, which is used by the operator to control the machine, and whose signals are connected to an input/output interface (Ilo>4).

In addition, each servo motor is equipped with a position detector 15X.
% t5y and 15z are connected, and their output pulses are input to the counter 1xs7ys1z.

In FIG. 2, which shows the distance measuring device moving on the model surface, IO is the distance measuring device, 13 is the model, and the surface of the model 13 has an inclination angle α with respect to the horizontal plane. Pl is the previous position of the distance measuring device 10, and P
2 is the position of the range finder lO after one sampling time, and P3 is the position of the range finder 1 when tracking is ideally performed.
0 and therefore at position P2.
It is necessary to control 0 so that it returns to the ideal position.

Next, we will describe a method for tracking along the tilt angle of the model. FIG. 3 shows a flowchart for operating the distance measuring device along the inclination angle of the model. In the figure, the numerical value following S is the step number.

[S1] Processor 1 receives an interrupt from timer 2 and starts sampling.

(S2) Read the distance WBL from the AD converter 5, and read ΔX, ΔY1ΔZ from the counters 7X% 7y, 7z.

[S3] Find the difference between the reference distance [, o and the measured distance.

ALL L ” Lo -L -・-・-・-(0)
(S4) From ΔLL obtained in S3, calculate the feed rate of each axis using the following formula.

vx=vCjcosα−・ΔLL・sinαVz=V
c −5in a+K・ΔLL−cosα・---
-・------... (b) Here, (1) C: Feed command speed K: Loop gain Vx: Y-axis feed speed Vzs Z-axis feed speed.

(S5) The feed speed of each axis determined in S4 is output to the DA converters 5x and 5z. This output is servo amplifier 3x,
Sent to 13z, servo motor 9x.

9z is controlled to the commanded feed rate.

[S6] Find the difference between the distance data La read last time and the distance data L read this time.

AL = L a −L −−−−−−−−−・−
(C) (S7) Based on the data in S6, calculate the inclination angle of the model using the following equation.

cr=earc, tan ((ΔZ+ΔL)/Δ
X) −・・−・−−−−−−−−−−・(d) [S8]
The distance data L measured this time is replaced with the distance data La and is prepared for the next calculation, and other processing is performed until the next interruption occurs.

In this way, it is possible to perform a follow-up operation along the inclination angle of the model.

In the above description, the X-axis was used as the reference axis, but the same control can be performed using the Y-axis as the reference axis. Also, X-
It is also possible to control in a similar manner using a direction at an arbitrary angle on the Y plane as a reference axis.

〔Effect of the invention〕

As explained above, in the present invention, the distance to the model surface is measured every time, the tilt angle of the ° model is determined from the 0 difference in distance, and tracking control is performed along the tilt angle, so tracking error becomes zero regardless of the tilt angle, allowing an accurate tracing control method.

[Brief explanation of the drawing]

Fig. 1 is an overall block diagram for carrying out the tracing control method of the present invention, Fig. 2 is a diagram showing the distance measuring device moving on the model surface, and Fig. 3 is a diagram showing how the distance measuring device is moved along the model's inclination angle. It is a flowchart figure for operating along. l−・−−−−−−・・−・−Processor 2−・−・−
・−・・−・・Timer 3−・・−・−・・−・・−
・・Memory 5・−・−−1−・−AD converter 6
x-----DA converter 6y-----
-DA converter 6z---------DA converter 7x--
・−・−・−Counter 7y−・−・−・・Counter 7z−・・・−・−・Counter lO−・・−・−−−−−−・・Distance measuring device 11−−−
−−・−・−・−・Column head 12・−・・−・・−
−−−−−−Table 13・・・−−−−・・・・・・・
−・− Model patent applicant Fanuc Co., Ltd. agent Patent attorney Takeshi Hattori Figure 2

Claims (2)

[Claims] (1) In a tracing control method in which a machine having at least three axes of moving parts measures the distance to the model surface and performs tracing control, the distance to the model surface is measured at regular intervals, and each of the aforementioned Read the position of the axis, calculate the movement amount ΔX of the reference axis of one of the three axes, the movement amount ΔZ of the Z axis, and the increase/decrease in distance within a certain time ΔL, and calculate the distance between the reference axis and the Z axis. The inclination angle α of the model in the plane formed by ) as a deviation, calculate the corrected speed component K (L-L_0) from the deviation and loop gain, and calculate the speed of each axis using the following formula from the tilt angle α and the corrected speed K (L-L_0). Then, Vx=Vc・cosα−K(LL−L_0)・sinαV
z=Vc・sinα+K(LL_0)・cosα A tracing control method characterized in that the model surface is tracked. (2) The tracing control method according to claim 1, characterized in that the distance to the model surface is measured with a laser distance measuring device.