JPH0113992B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention provides two tracing devices, causes the first tracing device to perform model tracing, and based on the modeling, the second tracing device side is compared to the first tracing device. The present invention relates to a master-slave type profiling control device which generates a movement command and simultaneously performs profiling on the second profiling device side based on the movement command. <Prior art> A master-slave type tracing system has at least two tracing devices, the first tracing device side (master side) traces a model, and the second tracing device uses the second tracing device based on the tracing. A movement command is generated on the profiling device side (slave side), and processing is performed on the slave side based on the movement command. Each tracing device constituting such a master-slave type tracing system traces a model to a tracer head, calculates a speed command for each axis in a tracing control circuit using the amount of displacement detected by the tracer head, This generates analog speed commands, which drive the motors of the corresponding axes to move the tool relative to the workpiece, and also use the tracer head to align the model surface, and perform these operations. It has the function of repeatedly machining the workpiece into the same shape as the model. In addition, the analog speed command voltage output from the tracing control circuit of the tracing device (master side) can be used to control the speed of the other tracing device (slave side) as appropriate via the analog gate. The configuration is such that the voltage is applied to the unit. <Disadvantages of the prior art> As described above, in the conventional master-slave system, the speed control signal was commanded as an analog voltage input to the speed control unit, so the movement command sent from the master side to the slave side is also analog. It is output as a value, and as a result, it is vulnerable to disturbances such as power supply voltage fluctuations and noise, and cannot generate accurate commands, resulting in the disadvantage that high-precision tracing machining cannot be performed. In addition, special public service No. 44-23273
The publication describes an invention in which the tables of the copying machine and the processing machine are separated and each is provided with a feeding pulse motor to prevent a decrease in processing accuracy due to vibrations caused by cutting being transmitted to the stylus side. .
Here, multiple controlled machines are connected in parallel to one copying machine, and all the controlled machines receive the same motor drive command, that is, the feed is the sum of the batch and pitch error signals corresponding to the first machine. Since the pulse signal is transferred, it is possible to eliminate the influence of disturbances, but there is a problem in that it is not possible to accurately correct the pitch error or correct the consistency for each controlled machine after the second machine. <Object of the invention> The object of the present invention is to form a speed command using a digital signal in a master-slave type profiling control device for simultaneously profiling multiple workpieces from one model, and to transfer the speed command from the master side to the slave side. It is an object of the present invention to provide a tracing control device in which the movement command sent out is also digital value control data. <Summary of the Invention> The present invention provides a tracing control device for tracing and controlling each axis motor of a tracing machine tool using a detection signal generated from a tracer head, and a speed command function for controlling each axis motor based on the detection signal. The first and second profiling devices each have a positioning function that does not rely on tracing and perform independent profiling, and the first profiling device side monitors the current position or amount of movement of the movable part that performs profiling. A monitoring means and digitally transmitting the current position of the tracer head or the amount of movement within a predetermined time detected based on the monitoring result on the side of the first tracing device as a movement command for the movable part to the second tracing device. a signal transmission means, the model is traced by a tracer head on the first tracing device side;
This profiling control device is characterized in that it causes a second profiling device to perform profiling according to the shape of the model based on a movement command based on the profiling. <Embodiment> FIG. 1 is a block diagram of a tracing device applicable to a master-slave tracing system according to the present invention, showing only the Z-axis control system. Tracing machine tool side
TCM has an X that drives table TBL in the X-axis direction.
A Z-axis motor XM that drives the column CLM to which the tracer head TC and cutter head CT are attached in the Z-axis direction, and a Y-axis motor YM that moves the table TBL in the Y-axis direction are provided. . Model MDL and workpiece on table TBL
WK is fixed, tracer head TC is model
Cutting head CT in contact with the surface of MDL
Processes the workpiece WK according to the model shape. As is well known, the tracer head TC is configured to detect the displacements ε _x , ε _y , and ε _z of the surface of the model MDL in the X, Y, and Z axes, and the displacements in each axial direction detected by the tracer head TC is input to a tracing control section TCC composed of a microcomputer, where well-known tracing calculations are performed and speed commands in each axis direction are digitally generated. Now, as a training method,
Considering the surface profile on the −Z plane, digital velocity commands V _x and V _z are generated. Of this digital speed command, V _z is sent to the multiplexer.
Via MPX, it is input to the digital-to-analog converter (DA converter) DAC, which converts it into an analog speed command voltage _Vc , which is then output to the speed control unit.
Applied to VCC. Note that during tracing control, the tracing mode signal TCM is generated and the multiplexer
MPX is designed to only pass V _z . The speed control unit VCC drives the Z-axis motor ZM based on the difference between the actual speed voltage V _a generated by the tachogenerator TG and the speed command voltage V _c . At the same time, the X-axis motor XM is driven in the same way, and the cutter head CT moves relative to the workpiece WK.
The workpiece is processed according to the model shape, and the tracer head TC follows the surface of the model MDL. Thereafter, the tracer head TC generates displacement amounts ε _x , ε _y , and ε _z according to the model shape, and inputs the displacement amounts to the tracing control unit TCC. Tracing control section
If the displacement amounts ε _x , ε _y , and ε _z are input, TCC performs a well-known tracing calculation based on the displacement amounts to determine the feed rate.
Calculate V _x and V _z . For example, the feed rate V _x is |ε−
The feed rate is controlled to be inversely proportional to the value of ε ₀ | (where ε is the combined displacement amount and ε ₀ is the reference deviation), and the feed rate V _z changes in proportion to the value of |ε−ε ₀ |. And (ε−
control so that ε ₀ ) becomes zero. Thereafter, the X-axis and Z-axis motors are driven by the newly calculated digital speed commands V _x and V _z , and the tracer head TC
moves along the model surface, and the cutter head CT moves in the same way as the tracer head, processing the workpiece WK in the same shape as the model MDL. On the other hand, when the Z-axis motor ZM rotates by a predetermined angle, a pair of feedback pulses P _a and P _b are generated from a position detector (for example, a pulse coder, a position coder, etc.) PSD that are shifted by 90 degrees from each other. Feedback pulses P _a and P _b are movement direction discrimination circuits
The voltage is applied to MDD, and the direction of movement is determined here. That is, since the direction of movement can be determined depending on whether the phase of pulse P _a is ahead of the phase of pulse P _b , the direction discrimination circuit MDD outputs the movement direction signal MDS to the gate circuit GTC depending on whether the phase is ahead or behind. . When the Z-axis motor ZM is rotating forward, the gate circuit GTC sends the feedback pulse P _a to the subtraction terminal of the reversible counter RCN.
Furthermore, distribution pulses P _s , which will be described later, are input to the addition terminals, and when the rotation is reversed, a feedback pulse P _a is input to the addition terminal, and a distribution pulse P _s is input to the subtraction terminal. Below, the method for monitoring the current position when the Z-axis motor is rotating forward (referred to as follow-up)
I will explain about it. With the generation of _m1 feedback pulses P _a , the content of the reversible counter RCN becomes _-m1 . The contents of this reversible counter RCN are read at predetermined intervals by the tracing control unit TCC and subjected to the calculation M+m ₁ →M (initial value of M is zero) (1). Also, the tracing control section TCC is m ₁
is input to the pulse distributor PDC. pulse distributor
When m ₁ is commanded, the PDC immediately performs pulse distribution calculation and outputs m ₁ distribution pulses P _s . This distribution pulse P _s is the OR gate ORG and the gate circuit
It is input to the addition terminal of the reversible counter RCN via the GTC, and its contents are updated one by one in the positive direction. Therefore, if the motor ZM stops after generating m ₁ pulses, the count value of the reversible counter RCN becomes zero due to the generation of m ₁ pulses from the pulse distributor PDC. However, if the Z-axis motor is rotating, the feedback pulse P _a is still input to the subtraction terminal of the reversible counter RCN in parallel with the above pulse distribution calculation, and its content is updated by 1 in the negative direction, and the pulse distribution Even if m ₁ distribution pulses are generated from the device, it will not become zero. Therefore, the time when the content -m ₁ is read from the reversible counter RCN is t ₁ , the time when m ₁ distribution pulses P _s is generated is t ₂ , and the time t ₁
If m ₂ feedback pulses _{P a} are generated _between
The content of RCN is −m ₂ . By the way, after a number of distribution pulses equal to m ₁ are generated (when sampling pulses of a predetermined period are generated), the tracing control unit TCC starts the reversible counter RCN.
Read the contents (−m ₂ ) again, perform the addition operation M+m ₂ →M ………(1)′, and add m ₂ to the pulse distributor.
Command the PDC. Note that M is (m ₁ +m ₂ ) due to the operation (1)'. From then on, every time a sampling pulse occurs, the tracing control unit TCC reads the contents of the reversible counter RCN -mi (i=1, 2, 3), and performs the addition operation of M+mi→Ni (=Σmi)......(1)'' At the same time, input the numerical value mi to the pulse distributor PDC.Then, repeat the above operation.The above is summarized as shown in the table below.It should be noted that at time t ₁
First, the control unit TCC converts the reversible counter RCN
It is the time when the contents of were read, and ti(i=2, 3,
) is the time at which the sampling pulse of period T is generated, and mi is the number of feedback pulses _{P a} generated between time ti-1 and ti. As is clear from this table, the feedback that occurred up to time tj+1

[Table] The total number M of pulses P _a can be expressed as M= _j+1 〓 ⁱ⁼¹ mi, which indicates the current position in the Z-axis direction, and is stored in the current position register in the tracing control unit TCC.
It is assumed that mi distribution pulses are reliably generated within one cycle of the sampling pulse T. The profiling control operation and the method of monitoring the current position during profiling control have been described above, but the profiling device TCU shown in FIG. 1 has a positioning function that does not rely on profiling, similar to the NC device. for example,
The tracing control unit TCC sends the movement amount ΔZ to the pulse distributor PDC, and the command movement direction signal to the gate circuit GTC.
CMD, NC mode signal to multiplexer MPX
When NCM is input, a distribution pulse P _s is generated from the pulse distributor PDC, and this distribution pulse P _s is input to the gate circuit GTC via the OR gate ORG.
If the command direction is positive, the gate circuit GTC sends the distribution pulse P _s to the addition terminal of the reversible counter RCN.
If it is negative, input it to the subtraction terminal. Now, if the command direction is the positive direction, the distribution pulse P _s is counted up in the reversible counter RCN, and the count value of the reversible counter is input to the DA converter DAC via the multiplexer MPX, where the analog It is converted into a command speed voltage _Vc and applied to the speed control unit VCC. The speed control unit VCC drives the Z-axis motor ZM based on the difference between the actual speed voltage V _a and the speed command voltage V _c to move the column CLM in the Z-axis direction. When the Z-axis motor ZM rotates, feedback pulses P _a and P _b are generated, and the reversible counter
Decrease the RCN count value toward zero. The count value of the reversible counter RCN gradually increases and becomes almost constant during steady state, causing the Z-axis motor ZM to rotate at a constant speed. When the distribution pulse P _s stops generating, the count value gradually decreases and the Z-axis motor decelerates. It rotates by the commanded amount and stops. If you want to move the machine tool manually, first select manual mode from the operation panel OPP. This allows the tracing control section to
TCC sends NC mode signal to multiplexer MPX
Output NCM. After that, by operating the manual feed switch or manual pulse generator provided on the operation panel, the control unit TCC sends the command movement direction signal CMD according to the manual feed direction to the gate circuit GTC.
The pulse generator POS also generates a pulse P _b , and thereafter the machine tool is moved in the same manner as with the distribution pulse P _s described above. FIG. 2 is a block diagram of a master-slave type tracing system according to the present invention.
The same parts as in the figure are given the same alphanumeric characters, and the master side is shown with a suffix 1 and the slave side is shown with a suffix 2. A signal transmission line LN is connected between the profiling device on the master side and the profiling device on the slave side, which digitally transmits the current position of the machine tool or the amount of movement within a predetermined time from the profiling control unit TCC ₁ to the profiling control unit TCC ₂ . connected by. Next, tracing control using the master-slave system will be explained. Set the mode selection switches on the operation panels OPP ₁ and OPP ₂ to master/slave mode, and input the distinction between master and slave. Tracing control section on the tracing device side (master side) where the master is instructed
The TCC ₁ outputs a tracing mode signal TCM to the multiplexer MPX ₁ , and the tracing control unit TCC ₂ on the tracing device side (slave side) to which the slave is instructed outputs the NC mode signal NCM to the multiplexer MPX ₂ . In this state, when tracing is activated, the master-side tracing device executes the aforementioned tracing operation and monitors the current position by follow-up control. Now, in follow-up control, the tracing control section TCC ₁ uses a reversible counter at every predetermined period T.
Read the count value of RCN ₁ - mi. Furthermore, this count value
mi is the distance that the machine tool moved in the Z-axis direction during the period T. The tracing control unit TCC ₁ uses this count value (travel amount) to update the current position according to the above-mentioned formula (1), and the tracing control unit TCC ₂ uses the movement amount and movement direction as a movement command on the slave side.
Output to. The tracing control unit TCC ₂ on the slave side outputs the movement amount data mi sent from the master side to the pulse distributor PDC ₂ , and also outputs the movement direction signal CMD ₂ .
is output to gate circuit GTC ₂ . pulse distributor
The PDC ₂ executes a pulse distribution calculation based on this movement amount data mi and generates a distribution pulse P _s2 . Distribution pulse P _s2 is OR gate ORG ₂ , gate circuit GTC ₂
is input _to reversible counter RCN ₂ via
MDL ₁ type of processing is applied. Although the above is a case in which the model is traced on the master side, it is also possible to trace the model independently using the slave side profiling control device and perform unique profiling processing. In addition, although we have explained the case where the master side movement amount mi is outputted every predetermined period as movement command data from the master side to the slave side, the current position of the master side every period T is outputted to the slave side as movement command data. , M _i −M _i-1 →mi may be calculated on the slave side, and mi may be output to the pulse distributor PDC ₂ . <Effects of the Invention> As explained above, according to the profiling control device of the present invention, the tracer head on the first profiling device side is used to trace a model, and the second profiling device is used to perform profiling processing according to the shape of the model. Since the current position of the tracer head or the amount of movement within a predetermined time is digitally transmitted as a movement command for the movable part to the second tracing device, pitch error and backlash correction adjustments can be made for each machine to be controlled. Not only can this process be easily performed independently for each controlled machine, but it can also eliminate the effects of external disturbances such as power supply voltage fluctuations and noise, allowing highly accurate tracing machining to be performed. In addition, since the positioning operation of the slave-side profiling machine tool can be digitally controlled, the configuration is easier compared to the conventional method in which the slave-side machine tool was controlled by analog voltage commands. , reliability is also improved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a tracing device applicable to the master-slave type tracing system of the present invention, and FIG. 2 is a block diagram of the master-slave type tracing system of the present invention. TCC, TCC ₁ , TCC ₂ ...Trailing control section,
MPX, MPX ₁ , MPX ₂ ...Multiplexer,
DAC, DAC ₁ , DAC ₂ ...DA converter, PDC,
PDC ₁ , PDC ₂ ...Pulse distributor, GTC, GTC ₁ ,
GTC ₂ ...Gate circuit, RCN, RCN ₁ , RCN ₂ ...
...Reversible counter, OPP, OPP ₁ , OPP ₂ ...Operation panel, POS, POS ₁ , POS ₂ ...Pulse generator,
MDD, MDD ₁ , MDD ₂ ...Movement direction determination circuit,
MDL, MDL ₁ ...Model.

Claims (1)

[Scope of Claims] 1. In a tracing control device for tracing and controlling each axis motor of a tracing machine tool using a detection signal generated from a tracer head, there is provided a speed command function for controlling each axis motor based on the detection signal. first and second profiling devices each having a positioning function independent of the profiling process and performing profiling processing independently; and a monitoring means for monitoring the current position or amount of movement of a movable part that performs profiling processing on the side of the first profiling device. and signal transmission for digitally transmitting the current position of the tracer head or the amount of movement within a predetermined time detected based on the monitoring result on the first tracing device side as a movement command for the movable part to the second tracing device. and a means for tracing the model using a tracer head on the first tracing device side, and causing the second tracing device to also perform tracing processing according to the model shape based on a movement command based on the tracing. Features a profiling control device. 2 The second profiling device forms a movement command for each axis motor of the profiling machine tool based on the digitally transmitted movement command, moves the movable part according to the command, and the movable part moves by a predetermined amount. The profiling control device according to claim 1, wherein the profiling control device controls the positioning of the second profiling machine tool so that the difference between the number of pulses and the number of commands is zero by generating pulses at each time. .