CA1184275A - Method of inputting positions of displacement in body moving apparatus - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Method of inputting displacements of movable bodies to an apparatus for automatically moving movable bodies to predetermined positions. A displacement of a body to a predeter-mined position is replaced with pulse signals by an encoder in such a manner that a unit displacement corresponds to one pulse, these pulse signals are counted by a counter, and the counted value is stored in a memory, whereby distance data is inputted based on the counted value thus stored.

Description

The present invention relates to methods of input-ting positions of displacement in an apparatus Eor moving bodies, and particularly to a method of inputting positions of displacement of a tool and a work into a memory of control means for controlling -the tool and the work in a boring machine, a milling machine, a lathe or -the like.
An invention relative to a me-thod of detecting positions of a movable body is described in Japanese Patent Application N 96524/79 to TO~OTA JIDOSHA KOGG~O KAB~SHIKI
KAISHA and laid open to the public under N 21745/81 on February 28, 1981.
According to this invention, in a method of detectin~ positions of a movable body by directly or indirectly replacing unit displacements of the movable body with digital pulse signals, a point where the movable body abuts against and press a stopper provided at a specified position within the moving scope thereof is made to be a reference position, a coincidence between a coun-t number of the pulse signals coun-ted from a reference number determined by the reference position and a set pulse number corresponding to a preset predetermined position is detected to detec-t an arrival of the movable body at the predetermined position, whereby the position of the movable body is reliably detec-ted, thereby enabling to provide a method of detecting positions of the movable body, wherein the assembling the method into a machine tool or the like is facilitated and the application of the method thereto is effected at low costs. However, here, in order to input a preset pulse number corresponding to the preset predetermined position, it has been necessary that the movable body is moved to the predetermined position, a distance from the reference position to the movable body is measured by use of slide calipers, a micrometer or a standard gauge, -the data should be inputted and stored in a memory by use of a digital switch or a key board. However, according to the above-described method, errors in measurement may occur, so that the operation i.s not correctly carried out~and moreover, -the measuring work is complicated.
The present invention has been developed in vi.ew of the above-described disadvantages and has as its object the provision of a method, wherein positions of displacement of a movab]e body can be accurately and readily input-ted and stored in a memory.
More particularly, according to the present i.nvention, there is provided a method of storing positional information of a reciprocable movable body from a reference position Eor the purpose of a body moving apparatus which lncludes, pulse generating means for emitting pulse signals in accordance wi-th a moving direction of the reciprocable movable body, each of said pulse signals indicating a unit displacement of said movable body, counting means for adding or subtracting a number of said pulse signals to or from a determ.i.ned reference number corresponding to the reference position and providing a counted pulse number, memory means for storing a set pulse number, which set pulse number being set with reference to said reference number and corresponding to a predetermined position within a range of movemen-t of said movable body, and means for judging whe-ther said set pulse number meets with said counted pulse number of said counting means after said set pulse number is stored i.n said memory means, to thereby judge if said movable body is at said predetermined position, said method comprising the steps of:
moving said movable body to said predetermined position to provide the counted pulse number corresponding to said predetermined position through said counting means;
and storing in said memory means said counted pulse number as said set pulse number.
The present inven-tion may also be defined as follows:
A method of storing positional information of a reciprocab],e movable body frorn a reference position for -the ,.,^ -- 2 -purpose of a body moving apparatus, said method comprising:
emittin~ normal or reverse rotation pulse signals Erom an encoder in accordance with a moving direction of the reciprocable movable body, each pulse signal indicating a unit clisplacement oE said movable body;
resetting an updown counter when said movable body reaches a reference position, for coun-ting said pulse signals emitted from said encoder during movemen-t of said movab].e body in a region other than said reference position, and providi.ng a counted pulse number through said updown coun-ter;
storing in a memory a set pulse number correspond-ing to a prede-termined posi-tlon within said region;
comparing said set pulse number, which has been stored by said memory, with the coun-ted pulse number of said updown counter to thereby judge if said movable body is at the predetermined position, moving said movably body to said predetermined position -to provide the counted pulse number corresponding to said predetermined position through said updown coun-ter;
and storing in said memory said counted pulse number as said set pulse number.
~he above-mentioned features and objects of the present invention will become more apparent from the following non restrictive description of preferred embodiments thereof taken in conjunction with the accompanying drawings, wherein like reference numerals denote like elements, and in which:
Figure 1 is a block diagram showing an embodiment of a machine tool, to which is applied the method according to the present invention;
Figure 2 is a block diagram enlargedly and schematically showing a control module and a program module illustrated in Figure l;
Figure 3 is a block diagram schema-tically showing another embodiment of the present invention;

Figure ~ is a flow chart showing -the fundamental operat.i.ons and procedures .in the embodiment shown in Figure l;
Figure 5 is a flow chart showlng a control flow in the flow char-t of Figuxe 4;
Flgure 6 is a flow chart showing a manual operation setting flow in the flow chart of Figure 4; and Figure 7 is a flow chart showing a teaching setting flow in the flow chart of Figure 4.
Description will hereunder be given of an embodi-ment, in which the present invention i.s applied for inputting the displacement positions of a tool and a work in a machine tool.
Figure l is a block diagram showing an embodiment of a machine tool, to which the present invention is applied.
A table for example, not shown, movably holding a work for e~ample, not shown, in a machine tool 400 is connected thereto with an encoder 200, which is adapted to replace a displacement of the table with pulse signals in such a manner that a unit displacement corresponds to one pulse. The encoder 200 may be either a rotary encoder for converting a rotary angle into pulses of a length or a linear encoder for conver-ting a linear distance into pulses of a length. For example, o~

pulse is set to 0.1 mrn. Pulse slgnals from the encoder 200 are i.nputted -to a con-trol module 100, which in turn operates in accordance with a program selec-ted and commanded by a program module 150. For lnstance, when the proyram module 150 commands an input of a position of the table for transferring the tool, the control module 100 counts the pulse signals from the encoder 200 and stores the position of the table in a memory thereof. Furthermore, when the program module 150 commands a control o~ the machine tool 400, the control module 100 counts the pulsè signals from the encoder 200, and, when the counted value coincides with a signal of the table position stored in -the memory of the control module 100, -the control modu:Le 100 sends a signal to a control panel 300 to operate a sequence circuit or the like for operating the machine tool, so that the machine tool 400 can be controlled by the operation of the control panel 300.
Fig. 2 is a block diagram enlargedly and schematically showing the control module 100 alld the program module 150 in Fig. 1, in which the control module 100 and the program module 150 are detachably connected to each other through a connector 140. The control.module 100 compri.ses: a program memory 102 for storing a program for controlling; a central processing unit (hereinafter referred to briefly as "CPU") 101 for successively performing control and calculation in accordance with the contents of the memory 102; an input~output 7~

ci.rcuit 106 Eor connecting CPU to ou-tside; and a random access memory (hereinafter reEerred to brlefly as RAM) 107 :Eor storing data Erom the program module 150, which can be varied by an user in accordance with uses. CPU 101, the memory 102, the input/ou-tput circuit 106, RAM 107 and the connector 104 are connected to one another through an address omnibus, a control omnibus and a data omnibus 105, respectively.
RAM 107 is connected thereto with a backup battery 108, which can prevent the data stored in RAM 107 from disappearing even if a main power source is temporarily cut off. Additionally, the input/output circuit 106 is connected thereto with: a counter 130; a direction discri-minating circui-tl24~(publicly known by Japanese ~tility Model Application Publication N 8574/77 published on February 23, 1977 to the name of HITAC~I DENSKI K.K.)for discrimi-nating the moving direction of the table based on a signal from an encoder 200 for emitting two pulse signals having a phasic difference of 90 therebetween, the two pulse signals being emitted, in the case of the reverse rota-tion of the encoder, in an emission order opposi-te -to that in the case of the normal rotation of the encoder; an indicator 121 for indicating errors; a timer 122; and an output relay 123 including a semiconductor switch or relay for emitting a control outpu-t. The program module 150 comprises: an input/output circuit 151 connected thereto with a connector 140; and indicator 152 connected to the~

~ ~ . . _ ~ - 6 -il~pUt/OUtpllt circuit 151., and a ]ceyboarcl 153. The keyboard 153 comprises: a mode selector key for selec-tirly modes such as a monitor mode, a setting mode and a teaching mode; a ten ~ey; and a control key for controlling -the settings and write-ins.
Description will now be given of action of the embodi-rment of the present invention explained in FigsO 1 and 2 with reference to the flow char-ts shown in Figs. 4 through 7.
Fig. ~ is a flow chart showing the fundamen-tal opera-tions. A power source for the whole apparatus is thrown~in,CPU 101 starts its operation in Step 11 in accordance wi-th a program from the program memory 102, advances -to S-tep 12, stores data frorn the encoder 200 beiny sto:red in RAM 107 immediately before the power is cut off and data showing the correspondence of the present position of the table to the position stored and set in a data area of the program mernory, returns the memory 102 and the input/output circuit 106 to the state ir~ediately before the power cut, and advances to Stép 13. In Step 13, CPU 101 judyes -the succeeding object to be achieved, and, when the program module (P-M) 150 is connected to the control module 100, advances to Step 15 for judging the presence of either the initial state where data showing a point (a table position stored and set) and data showing the correspondence of the point to the condition Gf the output relay are not inputted or a moni-tor mode having data previously 7~

inputted and sto:red and used to monitor whether the machine tool ~00 i.s operated in conformity wi-th the data or not.
~hell the con-trol module 100 is not connected to the program module 150, CPU 101 advances -to a control flow 14 where such a control is made that an output is actually fed to -the control panel 300 from the output relay 123 in accordance with the operation of the machine tool 400, and loops the control flow.
~ escription will hereunder be given oE a method of inputti.ng setti.ng data oE the correspondence o:E the point to the state of the point ou-tput relay 123 when the control module 100 is connected to the program modul.e 150.
Firstly, when the mode selec-tor key of the keyboard 153 is selected to a memory clear mode, P~M connection takes place in Step 13, then CPU 101 passes through Steps 15 and 17, advances to Step 2]. where CPU ].01 selects the memory clear mode at Step 21, advances to S-tep 22 where C:PU 101 clears a desirable data area as a whole to zero, and re-turns to Step 13. Subsequently, the mode selector key of the keyboard 153 is set to a setting mode, the setting mode is judged in Step 17, CPU 101 advances to Step 108, then to a manual operation flow 19, and returns to SteLo 13. Nex-t, when -the mode selector key of the keyboa.rd 153 is selected to a teaching mode, CPU ]01 advances from Step 13 through S-teps 15 and 17 to Step 18, a teaching setting flow is performed from Steps 18 through 20, and CPU 101 returns to Step 13.

-- 8 ~

Z~5 Subsequently, when the mode selector key of the keyboard 153 is switched over -to a monitor mode to actually operate the machine tool 400, CPU 101 advances from Step 13 to Step 15, and further advances to Step 16 where a relay output emitted based on the correspondence of a distance from the original point to the table at this time, the preset point and the state of the output relay outputted from the correspondence of the preset point to this distance are indicated by the indicator 152 in the Step 16, and then, CPU ].01 advances Step 14 to perform a control. flow, and returns to Step 13.
Description will. now be given of the manual operation setting flow with reference to Fig. 6. CPU 101 advances from Step ]8 to Step 52 to clear the memory, then, advances to Step 53, where the setting of the control key of the keyboard 153 and the write-in thereof are inputted, advances to Step 54, where a desi.rable point number is inputted through the ten keys of the keyboard 153 and stored in R~M 107, and advances to Step 55. In Step 55, the correspondence of the di.stance of the point to the state of the output relay 123 (for example, the output relay 1 is on at Poin-t Nos. 1, 2 and 5 and off at Point Nos. 3, 4, 6 and 7) is inputted through turning ON or OFF of the ten key and the control key of the keyboard 153 and stored in R~M 107, then CPU 101 advanced to Step 56, performs Step 56, where 1 is added to the initially set Point No., then, when it is not the final point, returns to Step 55, the s correspondences of the distances of the points to the states of -the output xelay are successively inputted, which is repea-ted until the E~nal point is completed, when the final point is completed, CPU 101 advances from Step 56 to Step 53, an end mark is written in RAM 107, in Step 59, the original point, allowable errors and frequency division ratio are set, and then, CPU 101 returns to Step 13, thus completing the man~al opera-tion setting flow~ In this manual operation setting flow, the relationships between Point Nos., which should necessarily be determined in the settlng stage of a control sequence and outputs of the switch can be readily set, however, the distance, another factor, cannot be set in most cases until a machlne tool is ac-tually operated to move a tool or a work to a desirable position and measure the distance, and, in ~eneral, the measurement of the type described is complicated, and moreover, proves to be inaccura-te in many cases.
Description will hereunder be yiven of the teaching setting flow according to the present invention with reference to Fig. 7.
In Step 18 of the basic routine shown~ in Fig. 4, when the teaching mode is inputted through the mode selector key oE the keyboard 153, CPU 101 advances to Step 20. In other words, CPU 101 advances to Step 82, in which, f~rstly, the correspondence of Point No. to the state of the output relay 7~

is inputted to be stored in ~ 107 throucjh the control key and the ten key of the keyboard 153. At thi.s time, data of distance is not set because it is sought through the teaching operation. Subsequently, CPU 101 advances -to Step 83, where CP~ 101 outputs a reset signal to clear the counter ]30, then, CPU 101 advances to Step 84, where CPU 101. discriminates the presence of an operation command (in operation or s-top) by a control signal, if the signal of stop is present, CPU 101 reaches Step 13 from Step 84 to repeat S-tep 13 until a con--dition oE "the machine too]. 400 is in operation" is brought about. When the condition is "in operation", CPU 101 advances to Step 85. When the operator moves the table, while ascertain-ing the positional relati.onship between the work and the tool, the encoder 200 outputs pulse signals in accordance with the distance of displ.ac~r~nt,c~nd the counter 130 counts the pulse signals. When the table reaches a desirable positi.on, -the table is stopped indisplac~nt. Subsequently, -the counted value of the counter 130 at this time (i~e~ the di.stance up to the point i.ntended fo:r) is written in P~M 107 throuyh the con-trol key of the keyboarcl 153, and CPU 101 advances to the succeeding Step 88, where one point is-added, and further, advances to Step 89. In Step 89, when it is not the final point, CPU 101 advances to Step 84, and the abovedescribed steps are repeated until the final point is reached. Additionally, in the final point, CPU 101 advances to Step 13, thus completing the teaching setting flow. Finally, description wi.ll be given of the con-trol flow with re:Eerence to F`ig. 5.
Firs-tly, when the proyram module 150 is disconnected from the control moclule 100, S-tep 13 is carried out to perform the con-trol flow of Step 14 as aforesaid. In the first place, in Step 32, the machine tool 400 is jud~ed whether it is in operati.on or at stop, when it is at stop, CPU 101 advances to 42, where the timer 122 is stopped, then returns to Step 13 to repeat the same until the condition of "-the machine tool 400 is in operation" is brought about. When the machine -tool is in operation, the timer ]22 for judging whether the encoder 200 is normally operated or not is started to detect the presence of an abnormality (for example, when even one pulse is not inpu-tted for one second, the encoder 200 is out of order), and, when an abnormality is presen-t, the error indicator 121 is operated, CPU 101 advances to Step 13 -to repeat the same until the normality i5 present, not shown. When the no~mality is present, CPU 101 advances to Step 34, where the direction discriminating circuit 124 judges whether the encoder 200 is rotated in the normal direction or in -the reverse direction, and, the rotation is in the normal direction, CPU
101 advances to Step 35, where a distance output xi from the counter 130 is written in, advances to Step 36, where a distance Xi of the desirable point is compared with the afore-said distance output xi, when the distance Xi and the distance output xi become equal in value to each other, CPU 101 advances -to Step 37, where -the output relay ]23 is operated and one point is added to the current point Pi (i.e., Pi + 1) to obtain the succeeding point to be perEormed, then, CPU 101 advances to Step 41, where the distance Xi of -the point Pi -~ 1 is set, and then advances to Step 13. In Step 3~, when Xi is larger in value than xi, CPU 101 advances -to Step 13 to repeat the same until x:i and Xi become equal. in value -to each other.
When the encoder 200 is rota-ted in the reverse direction, CPU
101 advances from St.ep 34 to Step 38, where the distance output xi from the counter 130 is written in, then CPU 101 advances to Step 39, where xi and Xi are equal in va:lue to each other, CPU 1.01 advances to Step 40, where the output relay 123 is opera-ted and one point is subtracted from the current point Pi (i.e., Pi - 1) to obtain the succeeding point to be performed, then, CPU 101 advances to Step 41, where the distance Xi of the point Pi - 1 is set, and further, advances to S-tep 13. In Step 39, when Xi is smaller in value than xi, CP~ 101 advances from Step 39 to Step 13 to repeat -the latter until xi and Xi become equal in value to each other~
Description has hereinabove been given of an example of using a computer. It should be understood, however, there is no intention to limit the invention to the specific embodiment disclosed, but on the contra-ry~ the inven-tion is to cover all modifications falling within the sprit and scope o:E the invention, for example, the invention can be worked by use of a coun-ter and a compara-tor, which t~7ill hereunder be explained wi-th reference to Fig. 3.
Major components in this case include an updown counter 131, a register 132 and a compara-tor 133. ~nputted at -the input side of the updown counter 131 are reset signals 137, normal. rotation pulse signals 134 and reverse rotation pulse signals 1.35 from the encoder 200 through the direction discri-mina-tlng circuit. 12~, while connected to the output side of the updown coun-ter 131 are one oE i.nput terminals of the comparator 133 and a memory, not shown. ~;urthermore, input-ted i.nto the inpu-t side of the register 132 are a reset signal 137 similar to that in the case of the updown counter 131 and pulse siynal da-ta Xi determined in accordance with a desirable point, and the output side of the register 132 is connected to the other of the input terminals of -the comparator ]33.
The comparator 133 compares the output xi from the updown counter 131 with the output Xi from the reglster 132/ and, when the both outpu-t eclual in value to each other, outputs an output signal.
Description will now be given of action of an ernbodiment shown in Fig. 3. Firstly, in the teaching mode, when the table is positioned at the original point, the reset signal 137 is inputted to the updown counter 131 to set the output to zero, and when the table is at a point other than the - 14 ~

7~

original point, -the reset signal 137 is no-t inputted and the table i.s movecl to a desirable point by a desirable method, the normal rotati.on pulses 134 or the reverse rotation pulses 135 are input-ted to the updown counter 131. Then, -the updown counter 131 counts the pulse signals from the encoder 200 outpu-tted in accordance ~i-th the c~isplac~n~nt distance and outputs the same as the output xi to a mernory, not shown. This memory stores therein this outpu-t xi, and can automat.ically stop the table of the machine tool 400 at a desirab]e point basecl on this s-tored data in the control ef~ected thereupon.
Namely, the data stored in the memory as the desirable point is inputted to -the regi.ster 132 as the data Xi r whereby the table starts moving to the preset point. During this displacement of the table, the pulse signals from -the encocler 200 are upGounted or downcounted by the updown counter 131 in accordance with the normal or reverse rotation of the encoder 200, and, when the resultant output xi becomes equal to the data Xi preset by the regi.ster 132, the comparator l33 ou-tpu-ts an output signal, whereby this output signal is inputted to the control panel 300, so that the table can be automatically s-topped at the preset point. ~ -From the foregoing description, it should he apparent to those skilled in the art that the abovedescribed emdodiment is but one of many possible specific embodimen-t which can represent the applications of the principles of the present 7~

invention. Numerous and varied o-ther arrangements can be readily devised by those skilled in the art without depar-tin~3 :Erom -the spirit and scope of the invention.

Claims (9)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1.- A method of storing positional information of a reciprocable movable body from a reference position for the purpose of a body moving apparatus which includes, pulse generating means for emitting pulse signals in accordance with a moving direction of the reciprocable movable body, each of said pulse signals indicating a unit displacement of said movable body, counting means for adding or subtract-ing a number of said pulse signals to or from a determined reference number corresponding to the reference position and providing a counted pulse number, memory means for storing a set pulse number, which set pulse number being set with reference to said reference number and correspond-ing to a predetermined position within a range of movement of said movable body, and means for judging whether said set pulse number meets with said counted pulse number of said counting means after said set pulse number is stored in said memory means, to thereby judge if said movable body is at said predetermined position, said method comprising the steps of:
moving said movable body to said predetermined position to provide the counted pulse number corresponding to said predetermined position through said counting means;
and storing in said memory means said counted pulse number as said set pulse number.

2.- The method of claim 1, further comprising the step of making said counted pulse number to be a predetermined number when said movable body reaches said reference position.

3.- The method of claim 1, further comprising the step of indicating an end mark when a number of set pulse numbers corresponding to all positions amongst a number of set positions of said movable body is stored in said memory means.

4.- The method of claim 2, further comprising the step of indicating an end mark when a number of set pulse numbers corresponding to all positions amongst a number of set positions of said movable body is stored in said memory means.

5.- The method of Claim 1, wherein, in said storing step, a key of a key board is operated to cause said memory means to store said counted pulse number.

6.- The method of claim 2, wherein, in said storing step, a key of a key board is operated to cause said memory means to store said counted pulse number.

7.- The method of claim 3, wherein, in said storing step, a key of a key board is operated to cause said memory means to store said counted pulse number.

8.- The method of claim 4, wherein, in said storing step, a key of a key board is operated to cause said memory means to store said pulse number.

9.- A method of storing positional information of a reciprocable movable body from a reference position for the purpose of a body moving apparatus, said method comprising:
emitting normal or reverse rotation pulse signals from an encoder in accordance with a moving direction of the reciprocable movable body, each pulse signal indicating a unit displacement of said movable body;
resetting an updown counter when said movable body reaches a reference position, for counting said pulse signals emitted from said encoder during movement of said movable body in a region other than said reference position, and providing a counted pulse number through said updown counter;

storing in a memory a set pulse number correspond-ing to a predetermined position within said region;
comparing said set pulse number, which has been stored by said memory, with the counted pulse number of said updown counter to thereby judge if said movable body is at the predetermined position, moving said movable body to said predetermined position to provide the counted pulse number corresponding to said predetermined position through said updown counter;
and storing in said memory said counted pulse number as said set pulse number.