U.S. patent application number 10/217043 was filed with the patent office on 2003-10-02 for cnc control unit with learning ability for machining centers.
Invention is credited to Balic, Joze.
Application Number | 20030187624 10/217043 |
Document ID | / |
Family ID | 28450346 |
Filed Date | 2003-10-02 |
United States Patent
Application |
20030187624 |
Kind Code |
A1 |
Balic, Joze |
October 2, 2003 |
CNC control unit with learning ability for machining centers
Abstract
A CNC control unit 1 with learning ability solves the problem of
automatic and intelligent generating of NC programs for CNC
machining centers for milling, drilling and similar operations. The
key module of the CNC control unit 1 is a neural network (NN)
device 7, that learns to generate the NC control programs through
an NN teaching module 4. Upon completion of learning process the NN
device 7 can generate automatically, without any intervention of
the operator, merely on the basis of the CAD 2D, 2,5D or 3D part
models, taken from a conventional CAD/CAM system 29, various new NC
control programs for different parts, which have not been in the
machining process before. The CNC control unit 1 with learning
ability is suitable especially for machining centers intended for
milling, including face milling (rough), contour milling (rough),
final milling following the contour and in Z-plane, final contour
3D milling, contour final milling, milling in Z-plane, final
contour milling on the equidistant, and milling of pockets;
drilling, including normal drilling, deep drilling, and center
drilling; and reaming, sinking and threading.
Inventors: |
Balic, Joze; (Maribor,
SI) |
Correspondence
Address: |
ST. ONGE STEWARD JOHNSTON & REENS, LLC
986 BEDFORD STREET
STAMFORD
CT
06905-5619
US
|
Family ID: |
28450346 |
Appl. No.: |
10/217043 |
Filed: |
August 12, 2002 |
Current U.S.
Class: |
703/1 |
Current CPC
Class: |
G05B 2219/33034
20130101; G05B 2219/45145 20130101; Y02P 90/02 20151101; G05B
19/4099 20130101; Y02P 90/265 20151101 |
Class at
Publication: |
703/1 |
International
Class: |
G06F 017/50 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2002 |
SI |
200200088 |
Claims
1. A CNC control unit 1 for machining centers for milling, drilling
and similar operations with learning ability and the ability of
automatic intelligent generation of NC control programs 28,
comprising a neural network (NN) device 7, a modified microcomputer
2, a comparison unit 15, a position measuring unit 16 and an
amplifier 17, the improvement comprising the NN device 7 that takes
instructions from the NN teaching module 4, which is not a
constituent part of the CNC control unit 1 and operates
independently taking as a basis for its operation the data package
received from a conventional CAD&CAM system, in order to
operate as intelligent programming module after the teaching
process is completed and to automatically generate adequate NC
control program 28 for a given part to be processed in the
machining center; the said NC control program 28 being fed to the
modified micro computer 2 including an internal interface 9 with
its first output connected to the position memory 11 and its second
output connected to the function memory 12, which accepts also the
manual input commands 6 fed through the manual input module 8 and
the decoding unit 10; the modified microcomputer 2 further includes
a function program module 14, with its input connected to the
function memory 12 and its output connected to the adaptable
interface system 18, and an interpolation program module 13 with
its input connected to the position memory 11 and its output
connected to the comparison unit 15 which has its other input
connected to the output of the position measuring module 16, to
which the position data 22 are fed from a position meter 20, while
the output of the comparison unit 15 is connected to an amplifier
17 which feds the geometric data 24 to the step motor 19.
2. The CNC control unit 1 for machining centers defined in claim 1,
wherein in the mode of intelligent and automated processing of a
CAD part model 5 into a specific NC control program 28 the data
package of the CAD part model 5 is fed to the N7N device 7, which
first identifies and classifies the individual geometric and
technological features 25 of the CAD part model 5 and then builds a
new CAD part model 26, which is transmitted to the NN milling
module 27, supplying on its output the NC control program 28 for
the processed part, the said NC control program 28 being fed to the
internal interface 9, which splits the data in the NC control
program 28 into a position package saved in the position memory 11
and into function data saved in the function memory 12, wherein the
NC function program 14, containing the technological data, is
transmitted through adaptable interface 18 to the NC machine 3,
while the NC position program, generated in the interpolation
program module 13, is sent over the comparison unit 15 and the
amplifier unit 17 to the step motors 19 of the NC machine 3
resulting in a suitable movement either of the parts support 32 or
of the tools 31 in accordance with geometric data 24, wherein the
position meter 20 perceives the movement and sends a regulated size
22 into the position measuring module 16, which transmits the data
to comparison unit 15, where the difference between the actual and
the programmed position is calculated, while the geometric data are
obtained from the NC control program for each part and are treated
in the position regulation circle 23.
3. The CNC control unit 1 defined in claim 1, that can
automatically generate the NC control programs by means of the
instructed neural network contained in the NN module 4 using the
engineering drawings 35 of parts, wherein in the learning phase the
NN device 7 is connected to the teaching module 4 which takes the
teaching NC programs 36 for different parts defined in engineering
drawings module 35 from the conventional CAD/CAM system 29, and
wherein the decision on the success of teaching is taken in the
decision module 38, subsequent to the testing module 37, so that in
case the decision is NO, the path 39 is active and the repetition
of the teaching process takes place, while on the other hand the NN
device 7 has learned enough, the path 40 is active and the
generated neural network is sent to the NN device 7.
4. The NN device 7 defined in claims 1, 2, and 3, wherein the said
NN device 7 is realized in a microprocessor technique and contains
an identification module 25 that recognizes the geometrical and
technological features of different CAD part models 5, a generating
module 26 that produces new feature based CAD models of parts, an
NN milling module 27, and an automatically generated NC control
program 28 for a given part.
5. The CNC control unit 1 defined in claim 1 wherein the NN milling
module 27 enables intelligent, automatic generating of NC control
programs that enable the following machining operations to be
executed on prismatic parts: milling, including face milling
(rough), contour milling (rough), final milling following the
contour and in Z-plane, final contour 3D milling, contour final
milling, milling in Z-plane, final contour milling on the
equidistant, and milling of pockets; drilling, including normal
drilling, deep drilling, and center drilling; and reaming, sinking
and threading.
6. The procedure of teaching in the CNC control unit 1 defined in
claims 1, 2, 3 and 5, the improvement comprising a process of
generation of NC control programs in a conventional CAD/CAM system
29 based on engineering drawings of parts, the said NC control
programs serving as teaching NC programs 36 in the NN module 4 that
instructs the NN device 7, wherein the decision on the success of
teaching is taken in the decision module 38, subsequent to the
testing module 37, so that in case the decision is NO, the path 39
is active and the repetition of the teaching process takes place,
while in case that the NN device 7 has learned enough, the path 40
is active and the generated neural network is sent to the NN device
7
Description
FIELD OF THE INVENTION
[0001] The invention relates to manufacturing technology, in
particular to programming and numerical control of machining
centers for milling, drilling and similar operations.
[0002] The conventional control units for the CNC (Computer
Numerical Control) machining tools, especially the control units
for machining centers intended for milling, drilling and similar
operations, typically contain a microcomputer, consisting of a
decoder, a position memory, a function memory, an interpolation
program, and a functions program. The NC program is fed to the
computer either through a punched tape reading device or in a DNC
(Direct Numerical Control) mode through an interface. A manual
input is also foreseen, but it is limited to smaller corrections of
the NC control program or to individual changes of technological
parameters. The NC functions program comprising the technological
data is sent to the NC machine through an adaptable interface. The
NC positions program is send through a comparison unit and an
amplifier unit to a step motor of the NC machine. Either the
support for the part or the cutting tools of the machine can be
moved following the geometric data. A position meter perceives
every movement and sends a regulated position value to a
position-measuring module, which forwards the data to comparison
unit, where the difference between the actual and the desired
position is calculated. The geometric data is obtained from the NC
control program for the part and is processed in the position
loop.
[0003] A new NC control program must be supplied to the CNC control
system for each part, as the control system does not remember the
operations already performed and can not automatically change the
program parameters, with the exception of some technological
parameters, for example the cutting conditions, corrections of tool
length, offset of reference or zero points.
[0004] The use of modern CAD/CAM systems does not solve this
problem. These systems just enable that a new NC control program is
performed faster and more reliably. Some systems allow saving of
certain processing strategies, nevertheless, the intervention of
skilled NC programmer is still necessary. The programs made in this
way cannot be used directly for the CNC control of the machine
tool; they must be adapted in a post-processing phase. The task of
this phase is to modify a generally valid file of the tool path
(CLDATA) for each machine tool, i.e. for each CNC control. Every NC
control program and every change must go through such
post-processing phase.
[0005] The technical problems indicated above can be solved by an
NC control system with learning ability and the ability of
automatic intelligent generation of NC control programs which
follow the computer read engineering drawings and/or 3D CAD models
of the parts to be processed.
[0006] In the patent DE4O1 1591 (JP19890098177) an NC control unit
with integrated learning function is described. The NC control unit
makes a teaching NC control program that is compared with the
inserted NC control program to make the resulting NC control
program. The actual NC control program can be changed or
supplemented by the machine operator who chooses the "teaching" way
of operation and then supplements the NC control program. The
solution requires the intervention of a skilled operator or a
programmer.
[0007] The patent application US2001/0000805 A1 describes a device
for generating a tool path on NC machines and the pertinent NC
control system. First, the device identifies the geometric feature
characteristics of a CAD model, and then it chooses the most
suitable tool path amongst the stored processing procedures
(machining cycles, sub-programs). Only the machining procedures,
which have been defined as typical processing procedures for
particular sub-programs, are available for selection.
[0008] The patent U.S. Pat. No. 6,022,132 describes a method and a
device for programming the CNC machine tools on the basis of a
probe built-in into the main spindle of the machine tool. The probe
is moved manually following the required profile (tool path). After
receiving the data the computer generates an automatic NC control
program, which gives the commands for the movement to the CNC
control system. This method does not include any elements of
artificial intelligence.
[0009] The patent US63 14412B1 describes an evolutional control of
a driving machine in a vehicle with respect to chosen coefficients.
A scheme of the control unit is constructed on the evolution
principles. The system is adapted for building-in into a
vehicle.
[0010] The patent EP0726509A1 describes an interactive programming
system for CNC machine tools. It allows the operator to choose
interactively between different control programs and procedures,
which are then automatically composed into an NC control program.
The solution requires the intervention of an operator or a
programmer.
[0011] The patent JP2001034155 describes a learning method and a
device made for this purpose. A special man-machine interface is
built-in into the control unit of the machine to enable a
conversation with the user and the learning process.
[0012] The patent JP 11242510 describes a device and a method for
generating the NC control programs. A special device saves the data
about the part, pertinent coordinates, junction's characteristics
and the time necessary for assembling the individual electronic
components. The solution enables a reduction of time needed for
preparing the NC control programs and a reduction of mistakes
arising at preparing the programs.
[0013] In all the solutions presented above manual intervention of
a skilled operator or a programmer is necessary for preparing the
NC control program for CNC machine tools. The systems cannot create
the NC control programs for the parts, which are not saved in the
database, and cannot choose and use the machining strategies
automatically.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The object of the invention is to provide an improved
programming and numerical control for machining centers intended
for milling, drilling and similar operations which has the learning
ability and the ability of automatic intelligent generation of NC
control programs. The said object of the invention is achieved by
means of a neural network (NN), which learns to generate NC control
programs through a teaching module. Consequently, the NC control
programs can be generated automatically without any intervention of
the operator, merely on the basis of the 2D, 2,5D or 3D computer
models of the parts to be processed.
[0015] The objects, advantages and features of the invention will
be presented in detail by means of drawings in the following
figures:
[0016] FIG. 1--shows a block diagram of a CNC unit with learning
ability for machining centers according to present invention,
[0017] FIG. 2--shows a schematic layout of a neural network device,
FIG. 3--shows a flow chart of learning and generating the neural
network, FIG. 4--shows a schematic layout of the neural
network.
[0018] The learning process and the automatic intelligent
generation of the NC control programs 28 take place in a neural
network (NN), built-in in a special NN device 7, which receives the
learning instructions from the NN teaching module 4. The NN
teaching module 4 is not a constituent part of the CNC unit 1 and
works independently. Upon completion of learning process the NN
device 7 can generate automatically, merely on the basis of the CAD
part model 5, coming from conventional CAD/CAM system 29, and
without any intervention by the operator, various new NC control
programs 28 for different parts, which have not been in the
machining process before.
[0019] The NC control programs 28 are fed from the NN device 7 to a
modified microcomputer 2, which includes internal interface 9 for
transmission of NC control programs 28 to a position memory 11 and
to a function memory 12. To the function memory 12, the manual
commands 6 from the manual input module 8 can be fed as well, to
wit through the decoding module 10. The commands 6 are mostly of
technological nature, i.e. feed rate, revolution speed, switch
on/off of cooling liquid etc.
[0020] The teaching data for the NN device 7 come from a special
teaching module 4, which is not a constituent part of the CNC
control unit 1. The task of the teaching module 4 is to teach the
neural network in the NN device 7 the principles and the technology
of NC programming for all the machining operations on CNC machining
centers, above all for milling, drilling and similar
operations.
[0021] In general, different neural network systems and different
software products, also software developed for commercial purposes,
can be applied. However, if special criteria have to be considered
and met in machining processes, e.g. costs, time, quality of
cutting, tool life, high speed cutting etc., the neural networks
developed especially for specific purposes should be used.
[0022] The schematic diagram of the NN device 7 according to the
invention is shown in FIG. 3. The NN device 7 consists of a module
25 designed to recognize geometric and technological features from
CAD part model 5 and to generate the features based CAD part model
26. The CAD part model 26 is fed to the NN milling module 27, which
has before that, namely in the learning phase, been instructed by
the NN teaching module 4 to generate the specific NC control
program 28 for specific machining operation, e.g. for milling or
drilling or similar operation.
[0023] In the learning phase, the N7N device 7 is connected to the
teaching module 4 designed for instructing the neural network (NN).
The teaching module 4 takes the data from conventional,
commercially available CAD/CAM system for programming the NC/CNC
machine tools. By means of a conventional CAD/CAM system 29, the
teaching NC programs 36 are prepared for different parts, defined
in engineering drawings module 35, and are sent to the teaching
module 4. In the decision module 38, subsequent to the testing
module 37, the decision is taken on the success of teaching. In
case that the decision is NO, the path 39 is active and the
repetition of the teaching process takes place. If on the other
hand the NN device 7 has learned enough, the path 40 is active and
the generated neural network is sent to the NN device 7.
[0024] The functioning principle of the NN device 7 is shown on
FIG. 4. The neural network built-in in the NN device 7 consists of
three layers: the input layer 43, the hidden layer 44 and the
output layer 45. On the input layer 43, the X-Y-Z sets 42 of
coordinate points appear, representing the coordinate point values
obtained from the modified CAD model 26 for individual machining
operations types 41. The coordinate point values are determined
according to special procedure. Through the intermediate hidden
layer 44 the input coordinates are transposed into output layer 45
in a form of a set of coordinate points X.sub.1, Y.sub.1, Z.sub.1
46, representing the position values of the tool path for
individual machining operations.
[0025] By means of the neural network the following machining
operations can be carried out: face milling (rough), contour
milling (rough), final milling after the contour and in Z-plain,
final contour 3D milling, contour final milling, milling on
Z-plain, final contour milling on equidistant, milling of pockets,
normal drilling, deep drilling, centering, reaming and
threading.
[0026] The CNC control unit 1 according to the invention can
function in either of the following two modes:
[0027] 1. Programming mode, i.e. the mode of intelligent and
completely automated processing of a CAD part model into a specific
NC control program.
[0028] 2. Learning mode, in which a learned NC programming system
based on the principle of a neural network is entered through the
teaching module 4 into the NN device 7.
[0029] The principle of generation of the NC control program is
shown in FIG. 4. In the programming mode, the CNC control unit 1
gets the data package of the CAD part model 5 from the
conventional, commercially available CAD/CAM system 29 intended for
programming the CNC machines. The model is then transmitted to the
NN device 7, which identifies and classifies the individual
geometric and technological features 25 of the CAD part model.
Based on these characteristic features a new CAD part model 26 is
built, which is transmitted to the N7N milling module 27, where on
the basis of learned intelligent procedures the most suitable
machining operations and cutting parameters (cutting speed,
feed-rate and the depth of cutting) with respect to chosen
conditions (machining time, surface quality, machining costs) are
defined.
[0030] The output of the NN milling module 27 is the NC control
program 28 for the processed part, which includes the geometric
data about the mode of cutting tool path (linear G01 or circular
G02/G03 interpolation), the coordinates of the cutting tool path
(e.g. milling cutter), the technological data (revolution speed,
feed-rate, depth of cutting) and auxiliary data (coordinates of
reference, zero and starting points, direction of rotation of the
main spindle M02/M03, change of cutting tools M06, etc.).
[0031] The data is then transmitted to internal interface 9, which
splits the data in the NC control program into tool path data
(coordinates of movement in axis X, Y, Z and/or rotation A, B, C
around coordinate axis X, Y, Z) saved in position memory 11 and
into functions data (M, S, T) saved in function memory 12.
[0032] The NC functions program 14, which contains the
technological data, is transmitted through adaptable interface 18
to the NC machine 3. The NC position program is then sent through
the comparison unit 15 and the amplifier unit 17 to the step motors
19 of the NC machine 3. Either the machine tool slide 32 or the
cutting tools 31 can be moved in accordance with geometric data 24.
The position meter 20 perceives the movement and sends a regulated
value 22 into the position-measuring module 16, which transmits the
data to comparison unit 15, where the difference between the actual
and the programmed position is calculated.
[0033] The geometric data are obtained from the NC control program
28 for each part and are treated in the position regulation circle
23.
[0034] In the learning mode, the learned NC programming system
based on the principle of a neural network is fed to the NN device
7 through the teaching module 4, which conducts the teaching of the
NN device 7. The functioning of the NN module is schematically
shown in FIG. 3.
[0035] The origin for the teaching process is the engineering
drawing 35 of a prismatic part, suitable for processing on
machining centers, designed for milling, drilling and similar
operations. First, the teaching NC program 36 is generated by the
conventional CAD/CAM system 29 and sent to the NN teaching module
4. Then, testing 37 of the obtained NC program is performed. In the
decision module 38, the decision is brought on whether the NC
control program is suitable and whether the neural network in the
NN teaching module 4 has learned enough. In the beginning the
statement NO 39 is valid and the teaching process is repeated using
the engineering drawing 35 of another part. In such a way the
series of teaching cycles is performed until the testing 37 shows,
that the decisional condition in the IF module 38 is fulfilled,
i.e. that the state 40 is accomplished. Here, the teaching process
of the NN module ends and the learned neural network is transmitted
into the NN device 7.
[0036] The CNC control unit 1 can learn how to generate the NC
control programs for the following machining procedures:
[0037] 2.1--milling
[0038] 2.1.1--face milling (rough)
[0039] 2.1.2--contour milling (rough)
[0040] 2.1.3--final milling following the contour in Z-plane
[0041] 2.1.4--final contour 3D milling
[0042] 2.1.5--contour final milling
[0043] 2.1.6--milling on Z-plane
[0044] 2.1.7--final contour milling on equidistant
[0045] 2.1.8--milling of pockets
[0046] 2.2--drilling
[0047] 2.2.1--normal drilling
[0048] 2.2.2--deep drilling
[0049] 2.2.3--centering
[0050] 2.3--reaming,
[0051] 2.3--sinking
[0052] 2.4--threading
[0053] The NN device 7 can be built-in into any CNC control unit
for milling machines as shown in FIG. 1. The standard parallel data
transmission is used. In case that it is not possible to reprogram
the internal interface 9, the NN device must be connected to
existing DNC interface, which is a constituent part of every CNC
control. The NN teaching module 4 is connected to the NN device 7
by means of a standard serial interface. The CAD part model 6 is
sent to the NN device 7 through a standard communication
interface.
[0054] For teaching of the NN device 7 through the teaching module
4, different commercially available CAD/CAM programming systems 29
can be used, for example Unigraphics Solution, I-Deas, Catia,
HyperMill etc.
* * * * *