Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
2002-04-19
2004-10-05
Knight, Anthony (Department: 2121)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S047000, C700S088000, C700S188000, C700S252000, C318S568100, C318S568130, C318S568150, C318S568180, C318S625000, C703S002000, C703S007000, C901S005000
Reexamination Certificate
active
06801830
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an operation confirming method when checking an actual operation path of industrial machinery which is provided with a plurality of shafts driven by servo motors in compliance with operation programs, and a control device suited to embodiments of the above-described operation confirming method.
BACKGROUND ARTS
Generally, where a job (welding and cutting) is carried out by industrial machinery (for example, industrial robots, machining centers) having a plurality of shafts, operation programs are prepared in advance, and the industrial machinery is caused to execute operations as per instructions by reading operation instructions written in the programs.
FIG. 13
is a configurational view showing the construction of a control device for a prior art industrial machine. In the drawing,
1
denotes a control device for industrial machinery, and the control device
1
is composed of an operation instruction data storing portion
2
, a shaft operation instruction preparing portion
3
, and a servo controller unit
4
. Also,
5
denotes a servo motor that drives an object industrial machine.
The operation instruction data storing portion
2
is a device that stores operation programs prepared in advance and reproduces the same. When executing the operation programs, instruction data are sequentially read from the operation instruction data storing portion
2
into the shaft operation instruction preparing portion
3
. Instruction data are control points of an object industrial machine, that is, end-effecter attaching portions in the case of industrial robots, or a position and a speed at a point that is used as a tool attaching reference in the case of a machining center, wherein a position Pi (i=0 through N−1, N: Number of all actuating points) and a speed Vti (Operating speed of Pi through Pi+1) are sequentially read into the shaft operation instruction preparing portion
3
.
In the shaft operation instruction preparing portion
3
, the instruction data are converted to operation instructions (quantity of operation per unit time) &ohgr;j (j=1, , , M: M indicates the number of shafts) for servo motors
5
for respective shafts.
The operation is called “inverted conversion” for general industrial machinery, and is called “pulse distribution” in an NC (Numerical Control) apparatus used for a machining center, etc. Respective shaft operation instructions &ohgr;j that are prepared herein are transmitted to the servo controller unit
4
, and the servo controller unit
4
controls a servo motor
5
so that respective shafts of the servo motor
5
operate as per instructions &ohgr;j.
In industrial machinery having such a construction as described above, before executing an actual job (welding, cutting, etc.), it is necessary to check whether or not the operation programs are prepared as intended. That is, it is checked whether or not control points of the industrial machinery operate while drawing an intended path. At this time, if any part of the program is inadequate when the industrial machinery is actuated at a speed that is designated by the operation program (hereinafter, an actual operation instruction speed), not only may an actual workpiece and/or fixture be damaged, but also an operator may be subjected to danger. Therefore, it is general that the industrial machinery is not operated at an actual operation speed, but is operated at lower speed than the actual operation speed.
In order for the industrial machinery to be operated at a lower speed, as shown in
FIG. 14
, the actual operation instruction speed Vti that is read from the operation instruction data storing portion
2
is passed through a low speed instruction converting portion
6
before transmitting the same to the shaft operation instruction preparing portion
3
. In the low speed instruction converting portion
6
, the instruction speed is decreased to a ratio &agr;(0<&agr;<1) that is designated in advance. That is, Via=Vti*&agr; is transmitted to the shaft operation instruction preparing portion
3
as a new instruction speed.
However, the following problems exist where an operation check is carried out in this type of prior art control device.
FIG. 15
is a view showing a comparison of operation paths to describe the problems in an operation confirming method for industrial machinery, which is embodied by a prior art control device. In the drawing, P
0
is an initial position of the control point of industrial machinery. When an operation program is prepared, which brings about an inverted L-shaped channel in which the control point advances from Point P
0
to Point P
1
at a constant speed, and next advances from Point P
1
to Point P
2
at a constant speed, the operation path in an actual job not bypassing the low speed instruction converting portion greatly depicts an inward curve, skipping Point P
1
as shown by C
0
. This phenomenon is called an “inward short-cut” resulting from a so-called servo delay. The faster the speed becomes, the larger the curve becomes. On the other hand, if the speed is made lower, bypassing the low speed instruction converting portion, the operation path depicts a small curve outside the operation path C
0
as shown by C
1
. That is, there is a problem in that, when confirming operations at a low speed, the operation path cannot reproduce the actual operation path at an actual operation speed.
DISCLOSURE OF THE INVENTION
Therefore, it is an object of the present invention to provide an operation confirming method capable of making, in order to enhance an operation program correction efficiency, an operation path at an operation confirming time (teaching mode) as identical as possible to that of an actual job time (play mode); and a control device therefor.
In order to solve the above-described and other problems, an operation confirming method for industrial machinery, by which the operation path is confirmed by actuating industrial machinery provided with a plurality of shafts driven by a servo motor controlled by a servo controller unit at a lower speed than an actual operation speed, according to the first aspect of the invention, comprises the steps of inputting respective shaft operation instruction values &ohgr;j based on the above-described actual operation speed into a simulator, which reproduces a servo control loop at an actual operation speed in the above-described industrial machinery, and instructing a quantity &ohgr;sj/P, which is obtained by dividing an output &ohgr;sj from the above-described simulator by an appointed positive real number P to the above-described servo controller unit N times (however, N is the maximum natural number not exceeding the above-described real number P) as respective shaft operation instruction values.
Also, an operation confirming method according to the second aspect of the invention comprises the steps of inputting a quantity &ohgr;j/P, which is obtained by dividing respective shaft operation instruction values &ohgr;j based on the above-described actual operation speed by an appointed positive real number P, into a simulator, which reproduces a servo control loop at an actual operation speed of the above-described industrial machinery, N times (however, N is the maximum natural number not exceeding the above-described real number P), and instructing an output &ohgr;sij from the above-described simulator into the above-described servo controller unit as respective shaft operation instruction values.
In the operation confirming method according to the third aspect of the invention, where the above-described actual operation speed is smaller than an appointed value, a value of the above-described real number P is determined to be 1.0.
In addition, in the operation confirming method according to the fourth aspect of the invention, where respective shaft instruction values &ohgr;sj from the above-described simulator are smaller than values determined shaft by shaft in advance, a value of the above-described real number P is determined to be 1.0.
In th
Nakazato Tatsumi
Tomita Koji
Barnes Crystal J
Kabushiki Kaisha Yaskawa Denki
Knight Anthony
Westerman Hattori Daniels & Adrian LLP
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