JPH0650444B2 - Uniaxial tracing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a uniaxial tracing device.

Conventionally, in industrial robots, a finite number of passing points are specified on the path for PTP control (Point to point control).
l) and CP control (Continuous path control) that is specified as a straight line or a curve in the space of the work position and continuously positions and orients on the path.

By the way, in the case of adopting the former PTP control in the uniaxial tracing device, it is necessary to stop and teach each teaching instruction, and since the trajectory is uncertain, a large number of points must be taken. It takes time. In the CP control, it is necessary to perform a calculation of running a straight line between the two points taught, and it becomes very difficult when the rotary table rotates. Even if it can be realized, many teaching points must be taught, and the complication becomes a method, which is a problem.

Therefore, an object of the present invention is to provide a uniaxial tracing device having a simple control system and capable of continuous operation.

In the present invention, in order to achieve the above object, one of the two controlled objects is configured to simply generate a synchronization pulse, and the other controlled object uses this synchronization pulse as a kind of clock pulse. It is characterized in that the configuration is such that sequential control is performed.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 indicates the overall configuration of the uniaxial tracing device. The uniaxial tracing device 1 is composed of a rotary table 2, a moving table 3, a control device 4, and a teaching device 5.

The rotary table 2 is mainly composed of a rectangular table 6 and a table 7 rotatably provided on the table 6. A motor 8 for rotating the table 7 and an encoder 9 for detecting the rotational position of the table 7 are provided on the side of the table 6, and these rotary shafts 8a,
9a is connected to the rotating shaft 7a of the table 7 by belts 10 and 11. An instruction piece 25 for setting the data acquisition position is provided on the lower surface of the table 7, and a proximity switch 26 for detecting the instruction piece 25 and sending a data acquisition start signal is provided on the upper surface of the table 6. . In addition, 12 is a work provided on the upper part of the table 7, 13
Is a fixture for fixing the work 12 to the table 7.

The moving table 3 has a rectangular parallelepiped base 14 and a ball screw 15.
And a table 17 screwed to a ball screw 15 and a servo motor 16 for rotating the table. A tacho generator 18 for detecting the rotational speed and an encoder 19 for detecting the rotational position of the servo motor 16 are provided behind the servo motor 16, and a working nozzle 20 is provided above the table 17. There is.
In this example, the nozzle 20 is capable of ejecting a sealer agent or the like from its tip which prevents corrosion of the joint portion of the fuel tank of the vehicle. (In this embodiment, the work 12 shows a fuel tank or something similar thereto.) On the other hand, on the side of the table 14, proximity switches 21, 22, 23 for detecting the moving position of the table 17 are provided. It is provided. The proximity switch 21 can detect the forward end of the table 17, and the proximity switch 23 can detect the backward end of the table 17,
The proximity switch 22 can detect that the table 17 has been set to the position of origin alignment.

The control device 4 has a control circuit 27 mainly composed of the CPU Z80 shown in FIG. 2, and an operation plate 24 including a display plate, buttons, lamps and the like is provided on the front surface. The control device 17 includes the encoders 9 and 1
9, tacho generator 18, proximity switches 21,2
2, 23, 26 and a teaching device 5 described later are connected.

The teaching device 5 is composed of a main body 5a and a dial 5b, and is internally provided with an encoder 5c for manual operation shown in FIG. 2 that outputs a pulse in proportion to the rotation amount of the dial 5b.

The control circuit 27 includes a position control circuit 28 including a deviation value counter 29, a DA converter 30, an amplifier 31, and a servo unit 32, a movement amount counter 33, and an i / o port 3.
4, a main circuit 38 including a CPU 35 and a memory 36,
The main components are a teaching signal input circuit 40 including an encoder 5c and a waveform processing circuit 39, a synchronizing signal input circuit 42 including an encoder 9 and a waveform processing circuit 41, and a current value counter 37.

First, the position control circuit 28 will be described. The deviation value counter 29 adds a pulse (pulse from a waveform processing circuit 39 or a movement amount counter 33 described later) input thereto and at the same time outputs a pulse input from the encoder 19. Subtraction is performed, and when a deviation occurs as a result of the addition and subtraction, a digital value corresponding to the deviation is output to the DA converter 30.

The DA converter 30 and the amplifier 31 are adapted to convert the digital amount of the deviation value counter 29 into an analog amount and amplify the converted analog value before outputting it to the servo unit 32.

The servo unit 32 compares the voltage from the amplifier 31 with the voltage value input from the tacho generator 18,
The motor 16 is controlled while obtaining the deviation.

The current value counter 37 is for counting the pulses from the encoder 19, and can hold how much the motor 16 has rotated by the number of pulses.
The present value counter 37 is configured to add when the motor 16 rotates forward, for example, and to subtract when the motor 16 rotates backward.

Next, the main circuit 38 will be described.
In the teaching mode described later, each time a pulse is input from the synchronization signal input circuit 42, the function of sequentially storing the count value of the present value counter 37 in the memory 36 from its predetermined address, and the reconfiguration described later. In the mode, every time a pulse is input from the synchronization signal input circuit 42, the memory 3 stored in the teaching mode is input.
The data in 6 is taken out sequentially from the predetermined address (start address), and the difference of each data is multiplied by 1/4 to obtain 4
The movement amount counter 33 is divided into two times via the i / o port 34.
It has a function of outputting to. At the start of the reconstruction mode, the difference between the current value and the data of the head address in the memory 36 is output, and from the next time, the difference between the data and the previous data is output to the movement amount counter 33. It is like this.

The memory 36 is naturally composed of a RAM and a ROM, and the ROM has a predetermined control procedure or data (when these are transferred from the ROM to the RAM or when the ROM is set in the RAM before the start of operation). Is set as a program, but for simplification of description, the CPU 35 is assumed to have the function of this ROM (that is, the CPU 35 is set with a predetermined control procedure, data, etc.). ) The following description will be given.

The i / o port 34 is for inputting and outputting data to and from the CPU 35, and the data transfer from the i / o port 34 to the movement amount counter 33 is performed in parallel. External signals are input to the i / o port 34 from the proximity switches 21, 22, 23, 26 and switches provided on the operation panel 24.

Next, the synchronizing signal input circuit 40 is mainly composed of an encoder 5c for manual operation and a waveform processing circuit 39 built in the teaching device 5, and the encoder 5c is 1000p /
The pulse can be output at a rate of rev, and the waveform processing circuit 39 multiplies the pulse from the encoder 5c by 4 and shapes the waveform to output it to the deviation value counter 29 as a pulse train.

The synchronizing signal input circuit 42 is composed of an encoder 9 provided on the rotary table 2 and a waveform processing circuit 41 for shaping the waveform of the pulse from now on. The pulse input from the waveform processing circuit 41 to the CPU 35 is It acts as a kind of timing pulse at the time of fetching and outputting data to the memory 36.

Next, the operation and effect will be described. This example has a teaching mode and a reproduction mode. In the teaching mode, the teaching device 5 is operated to move the nozzle 20 along a required work line so that route information can be sequentially input. In the reproduction mode, the nozzle 20 can be moved by teaching according to the route data stored in the memory 36. Therefore, the teaching mode will be described first.

First, the teaching device 5 will be described. When the dial 5b of the teaching device 5 is operated in the teaching mode, a pulse is output according to the rotation amount from the encoder 5c. This is multiplied by 4 in the waveform processing circuit 39 and then output to the deviation value counter 29 as a pulse train. On the other hand, when pulses are accumulated in the deviation value counter 29, the motor 16 is rotated by this and the table 1
Move 7. On the other hand, when the motor 16 rotates, a pulse is output from the encoder 19 to the deviation value counter 29, so that the pulses in the deviation value counter 29 are subtracted by this number of pulses. When the number of pulses of the deviation value counter 29 becomes zero by this subtraction, the motor 16 stops. That is, by applying a pulse to the deviation value counter 29 by the teaching device 5, it is possible to drive the motor 16 and move the table 17 until the encoder 19 generates the same number of pulses as the number of pulses.

Next, the teaching mode will be described. First, when the push button for teaching mode provided on the operation panel 24 is pressed, the origin is first adjusted.
Specifically, the table 17 is moved to a position where the detection signal is input from the proximity switch 22, and the table 7 is moved.
Is performed by rotating to a position where the C-phase pulse is input from the encoder 9. At this time, the deviation value counter 2
9, the movement amount counter 33 and the current value counter 37 are all reset. Note that these controls are automatically performed based on a predetermined program.

Next, when the above origin adjustment is completed, the motor 8 is rotated at a low speed and the nozzle 20 is moved along the tracing line by using the teaching device 5. Here, when the proximity switch 26 is turned on by the rotation of the table 7, the storage start of data is instructed. Then, the CPU 35 sequentially stores the value of the current value counter 37 in the memory 36 from a predetermined address each time a pulse is input from the encoder 9. This acquisition ends when the work makes one round. (This is again indicated by the proximity switch 26) Therefore, during this time the teaching device 5
Is operated to move the nozzle 20 along the required work line of the work 12, and the locus of the nozzle 20 during this time is sequentially stored in the memory 36 as a numerical value. The pulse from the encoder 9 is usually 10
The frequency is about 0 Hz, and one pulse is output every 0.5 mm of the outer circumference of the work 2. However, this can be changed as desired by changing the rotation speed of the motor 8.

Next, the reproduction mode will be described. When carrying out this reproduction mode, first, the push button for the reproduction mode of the operation panel 24 is pressed. Then, similarly to the teaching mode described above, the origin adjustment is performed based on a predetermined program. When this is completed, the motor 8 is then activated and the table 7 rotates. When the proximity switch 26 is turned on by the rotation of the table 7, this becomes a start signal and the data stored during the teaching is extracted from the memory 36.

First, when the data of the head address is extracted, the CPU 35 compares this with the value of the current value counter 37, and loads the difference pulse to the movement amount counter 33 via the i / o port 34. The differential pulse of this data is loaded from the CPU 35 to the movement amount counter 33 in parallel.

On the other hand, when the movement amount counter 33 loads the differential pulse, the differential pulse is serially transferred to the deviation value counter 29. (In this example, this frequency is set to about 25 KHz.) This corresponds to P1 in FIG. 3, in which hundreds of ten pulses are sequentially transferred from the movement amount counter 33 to the deviation value counter 29. I understand. The time tP1 indicates that all the pulses have been transferred and the total number of pulses of the movement amount counter 33 has become zero (hence no pulses are output).

On the other hand, when pulses are accumulated in the deviation value counter 29 by the transfer, the number of accumulated pulses is reduced by D.
-A converter 30, amplifier 31, and servo unit 3
The motor 16 is driven via 2. This corresponds to Q1 in FIG. 4, and the number of pulses actually transferred from the movement amount counter 33 is M1.
Since a pulse as shown by R1 in the figure is output, it indicates that the actual integrated number is Q1. (Fifth
In the figure, the number of pulses from the encoder 19 is shown as a graph, but the integrated value of this number of pulses is the motor 16
It can also be viewed as the amount of movement of the table 17 driven by. Further, in this figure, OB indicates the movement amount during teaching, and AC indicates the actual movement amount during reproduction. Next, although the nozzle 20 is moved to a predetermined position by the output of the above-mentioned head data, after the start signal is output by the proximity switch 26, the encoder 9
When more pulses are output (at this point, the above-mentioned control has already been completed), this is transmitted to the CP via the waveform processing circuit 41.
It is input to U35 as a synchronizing pulse. Then CPU3
5 is used as a trigger to extract the data at the address next to the start address from the memory 36. When this data is extracted, the CPU 35 subtracts the previous data (that is, the first data) from this data, and halves the difference to about 2 m.
Each sevc is transferred to the movement amount counter 33 through the I / O port 34 four times in total. This difference is made 1/4 in order to make the servomotor 16 move smoothly. For example, as shown between P2 and P3 in FIG. 3, there is a time lag until the next pulse is output. If it is large, the movement of the servo motor 16 will be jerky, so in this example, as shown by P2 ', the pulse is 1/4 and this is 2 ms.
It is output every time. However, P shown in FIG.
Similarly, 3/4, P4, P5 ... Are also output one by one, but for simplification of description, this process will be omitted in the following description.

On the other hand, the movement amount counter 33 transfers the difference pulse transferred thereto to the deviation value counter 29 in the form of a pulse train having a frequency of about 25 kHz, so that the deviation value counter 29 accumulates the pulses. Therefore, similarly to the above, the servo motor 16 rotates until the accumulated number of pulses becomes zero to move the nozzle 20.

Thereafter, similarly, each time a pulse is output from the encoder 9, data is sequentially extracted from the next address, and the difference between the extracted data and the previous data is calculated to calculate P3, P4 in FIG. As indicated by P5 and P6, this difference data is transferred from the movement amount counter 33 to the deviation value counter 29. Then, the deviation value counter 29 drives the motor 16 so that the integrated value of the pulses due to this transfer becomes zero,
(Therefore, the cumulative number of pulses of the deviation counter 29 is the fourth
As a result, the nozzle 20 moves along a locus as indicated by AC with respect to the locus OB by teaching shown in FIG. (In FIG. 5, the integrated value of the pulses from the encoder 19 is shown.
In addition, in the teaching mode and the reproduction mode, when the table 17 is detected by the proximity switch 21 for detecting the forward end or the proximity switch 23 for detecting the backward movement, the table 17 is the same after that. Movement in the direction is restricted.

As described above, in this example, the workpiece 12 is used during teaching.
While operating the teaching device 5 while rotating at a low speed, the nozzle 20 is caused to draw a required locus, and this locus is replaced with the pulse number by the encoder 19, and this pulse number is output from the encoder 9 every time a pulse is output. The data is sequentially stored in the memory 36. Then, at the time of reproduction, every time the work 2 is rotated and a pulse is output from the encoder 9, the data stored at the time of teaching is sequentially extracted from the memory 36, and the servo motor 16 is driven by this. Is. By doing so, the nozzle 20 can be moved with respect to the rotation position of the table 7 almost in the same manner as during teaching.

Therefore, the pulse from the encoder 9 acts as a kind of clock pulse, and the servo motor 16 is driven in synchronization with this pulse, so that the rotation amount of the table 7 and the movement amount of the table 17 are related to each other. Although it can be controlled, it is the table 1 that actually controls the movement amount.
Only 7 will suffice. Therefore, unlike the case of operating a control system having a plurality of degrees of freedom at the same time as in the normal CP control, the control system has a preferable feature that the load on the control system may be half that of the normal two-axis control.

Further, since it is the synchronous type as described above, it is not necessary to redo the teaching as in the conventional case even if the rotation speed of the table 7 changes, so that it is extremely easy to change the line speed (change in the production amount). In addition to being able to cope with this, the rotation speed of the table 7 does not have to be controlled accurately, so that a normal general-purpose motor can be used as it is.

Further, at the time of teaching, since the data is automatically fetched only by operating the dial 5b of the teaching device 5 to move the nozzle 20, (at this time, the table 7
The rotation speed of can be freely changed as desired)
There is a feature that teaching can be simplified and the time can be shortened without the complexity of teaching that is required with a conventional keyboard or the like. (Note that the teaching device 5
Has a characteristic that only an encoder is required.) Unlike the conventional two-axis control device in which each is controlled by an individual control system, a synchronization signal (pulse from the encoder 9) from the rotary table 2 is transmitted. Since the table 17 moves in synchronization, even if the rotary table 2 fails and stops, the nozzle 20 stops on the spot, which is extremely excellent in terms of interference with the work 12 and work safety. ing.

Moreover, although the path information of the nozzle 20 is stored in the memory 36 as a discrete amount for every fixed time, in the present example, the path information is acquired every 0.5 mm on the outer periphery of the work 12 by the synchronizing pulse from the encoder 9. Is taken in and the data is continuously transferred to the movement amount counter 33 every 2 ms at the time of reproduction. Therefore, the route information is substantially updated every time a synchronizing pulse is input from the encoder 9. Since the teaching is performed, the resolution is extremely high, and there is also an excellent feature that continuous operation with extremely good followability can be performed.

It is needless to say that this example can be applied not only to jetting a sealer agent or the like but also to other work such as welding or painting. Further, it is needless to say that the work 2 is not limited to the fuel tank and other types can be applied. In addition, as the encoder 9, a potentiometer, a linear scale, or the like can be used. Therefore, for example, if a linear scale is used, it can be applied not only when rotating the work 2, but also when moving linearly (including reciprocating motion). Further, the work 2 can be manually moved as well as driven by a motor.

That is, the present invention provides a servo having a deviation value counter, a D-A converter for converting the value of the deviation value counter from digital to analog, and a servo system by a tacho-generator for controlling a motor by an analog value from the D-A converter. A position control circuit that includes a unit and an encoder that converts the rotation of the motor into a pulse and returns the pulse to the deviation value counter; a synchronization signal input circuit that generates a pulse for synchronization in proportion to the movement of a work or the like; A current value counter that counts pulses from the encoder, and in the teaching mode, the value of the current value counter is sequentially stored in the memory from a predetermined address in synchronization with the synchronizing pulse, and in the playback mode. The values stored in the memory are sequentially extracted from a predetermined address in synchronization with the synchronization pulse, and each synchronization pulse is extracted. By transferring the difference in the values in the deviation value counter to the deviation value counter, and operating the motor until the difference becomes zero, by configuring a uniaxial tracing device with a main circuit such as a CPU, Despite the above control, one of the control targets may have a configuration in which only the synchronization pulse is simply generated, so that there is an excellent feature that the control system can be halved.

Further, since the route data in the movement amount counter is stored in the memory every time the synchronizing pulse is input, the teaching is substantially performed every time the synchronizing pulse is input. In addition, since the teaching points are extremely subdivided, there is also a very preferable feature that continuous operation with excellent reproducibility can be performed.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is an explanatory view showing the overall structure of a uniaxial tracing device, FIG. 2 is a block diagram showing a control circuit, and FIG. 3 is an output from a movement amount counter. A pulse diagram, FIG. 4 is a diagram showing the count number of the deviation counter, and FIG. 5 is a diagram showing the movement amount during teaching and the actual movement amount. Reference numeral 19 ... Encoder, 28 ... Position control circuit 29 ... Deviation value counter, 30 ... DA converter 32 ... Servo unit, 37 ... Current position counter 38 ... Main circuit, 42 ... Sync signal input circuit

Claims (1)

[Claims] 1. A servo having a deviation value counter, a DA converter for converting the value of the deviation value counter from digital to analog, and a servo system by a tachogenerator for controlling a motor by an analog value from the DA converter. A position control circuit that includes a unit and an encoder that converts the rotation of the motor into a pulse and returns the pulse to the deviation value counter; a synchronization signal input circuit that generates a pulse for synchronization in proportion to the movement of a work or the like; A current value counter for counting the pulses from the encoder, and in the teaching mode, the value of the current value counter is sequentially stored in the memory from a predetermined address in synchronization with the synchronization pulse,
In the reproduction mode, the value stored in the memory is sequentially extracted from a predetermined address in synchronization with the synchronizing pulse, and the difference in value between the synchronizing pulses is transferred to the deviation value counter. And a main circuit including a CPU that operates the motor until the difference becomes zero. The pulse for synchronization is generated according to the rotation of the work, and the pulse for synchronization is provided at the time of teaching during reproduction. When the values of are equal, the value in memory is sent to the deviation value counter,
A uniaxial tracing device characterized by position control based on the deviation of the current value.