JPH05250017A - Synchronizing method for industrial robot - Google Patents

Abstract

PURPOSE:To synchronize plural robots controlled by plural controllers by substituting a reference phase angle through the reference phase angle data input/ output part of the other robot to the reference phase angle of the reference phase angle control part of the other robot by an external line. CONSTITUTION:Based on the regenerative cycle time of a work program beforehand, the reference phase angle is calculated to be increased at advancing speed which is made lower when the cycle time is increased. When this reference angle is advanced rather than the reference phase angle, a phase angle control part 5 of a first controller 2 for the first robot outputs teaching position data. The reference phase angle is passed through a reference phase angle data input/ output part 17 and substituted through a reference phase angle data input/output part 117 of a second controller 102 for the other robot to the reference phase angle of a phase angle control part 105 for the other robot by an external line 21. Thus, first and second controllers 2 and 102 can perform control at the same phase angle, and respective robots can be synchronized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial robot synchronizing method for synchronizing a plurality of robots each composed of a plurality of control devices.

[0002]

2. Description of the Related Art Conventionally, as means for synchronizing industrial robots controlled by different control devices, an output signal from one robot is connected to an input signal of the other robot,
An interlock system has been adopted in which the other robot waits until a signal from one robot is input. However, this is only for correcting the deviation between the two at some points during the operation cycle, and it is far from being always synchronized during the operation cycle. Further, even if the same teaching is given, it is impossible to operate in perfect synchronization due to individual differences and processing timing differences.

As a method for synchronously operating an industrial robot, there is a method widely known as line tracking control from the past. As a development of these methods, for example, Japanese Patent Application Laid-Open No. 60-144806, "Robot Line tracking control method "and Japanese Patent Laid-Open No. 60-175112," Working method on conveyor by industrial robot ". Each of these is for synchronizing one robot with a moving work, not for synchronizing a plurality of robots. On the other hand, as a method of synchronizing and driving a plurality of robots, for example, there is a method disclosed in Japanese Patent Application Laid-Open No. 3-90910 by the applicant. This is a method for synchronizing a plurality of robots controlled by one controller. It is possible, but synchronization of robots controlled by multiple control devices could not be realized.

[0004]

Conventionally, the moving speed and the moving time have been used as a method for instructing the speed of the robot. However, in the case where the data regarding the speed is taught by the value that determines the movement time between the two teaching points, there are the following problems. First of all, the speed data only determines how long it takes to move between two points, so at some point, such as when performing function processing other than movement and when inputting and outputting signals with peripheral devices. When the work is performed stationary, the interpretation of the function information and the signal input / output processing time occur, and the time is determined depending on the processing speed of the control device. Also, since there is always a dynamic delay between the command position and the current position in the robot servo system, the teaching 2
The reality is that even the moving time between points cannot be understood unless reproduced. For these reasons, the cycle time of the work program cannot be accurately known unless it is actually measured by regenerating it once, and even if the cycle time is obtained by actual measurement, it is due to fluctuations in ambient temperature and power supply voltage. Since it also changes, it is extremely difficult to control the cycle time.

If these robots are controlled by different control devices, even if the same teaching is given, the cycle time will be the same due to the individual difference of the control device and the manipulator itself and the timing of processing. That is, it was impossible to keep the robots synchronized with each other at all times. An object of the present invention is to provide a method for synchronizing an industrial robot that enables synchronization of a plurality of robots controlled by a plurality of control devices, which has been impossible in the past.

[0006]

Therefore, the present invention has solved the above-mentioned problems of the prior art by providing a synchronous control method for an industrial robot as set forth in the claims.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a control device for a first robot used in a synchronous control method for an industrial robot according to an embodiment of the present invention, and FIG. 3 is a block diagram, FIG. 3 is a block diagram showing the connection relationship between the first control device of the first robot of FIG. 1 and the second control device of another robot, and FIG.
FIG. 6 is an explanatory view showing the operation of the device of FIG.

In FIG. 1, reference numeral 1 is a first robot, and the operation of the first robot 1 is controlled by a first controller 2. The control device 2 sets the teaching data of the teaching data of the teaching program of the teaching data recording unit 3 for recording the teaching data of the work program, the function control unit 4 for instructing the function processing such as the general-purpose signal output and the waiting of the interlock signal, and the teaching data recording unit 3 to predetermined values. Phase angle controller 5, teaching data recorder 3, and function controller 4
And a phase angle control unit 5, a main control unit 6 that totally controls the operation relationship, a servo amplifier unit 7 that amplifies the teaching data output from the phase angle control unit 5 and drives the first robot 1,
And a reference phase angle data input / output unit 17 for transferring the reference phase angle data.

The phase angle control unit 5 in FIG. 2 is the same as that disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-90910, and detailed description thereof will be omitted. The teaching data recorded in the teaching data recording unit 3 is the phase angle data θ at each teaching step i.
_i and position data X _i . This phase angle data replaces the conventional speed data, and teaches the phase angle θ _i that sequentially increases as the teaching point progresses. As shown in FIG. 2, the phase angle control unit 5 includes a cycle time register 8 for presetting the reproduction cycle time T _C of the work program, and a phase angle increment value ΔC which decreases as the value of the reproduction cycle time T _C increases. The phase angle increment value register 9, the oscillator 10, the addition switch 11 driven by the oscillator 10, and the reference phase angle θ _r obtained by sequentially adding the phase angle increment value ΔC each time the addition switch 11 is driven. Has a phase angle register 12 for recording

Further, as shown in FIG.
Compares the reference phase angle theta _r recorded in the phase angle data theta _i and phase angle register 12 in step i of the teaching data recorded in the teaching data recording unit 3, the reference phase angle theta _r is the phase angle data theta _i Comparator 13 that outputs a signal when it exceeds
And a gate 14 that opens by the signal from the comparator 13 and outputs the teaching position data X _i of step i recorded in the teaching data recording unit 3 to the servo amplifier unit 7, and is always in the ON position, and normally the comparator 13 Is output to the gate 14, and when the function control unit 4 starts the function processing such as general-purpose signal output and waiting for interlock signal, the function is switched to the OFF position and the signal from the comparator 13 to the gate 14 is output. A position data output switch 15 is provided to cut off the transmission and stop the output of the teaching position data.

In addition, a signal from the comparator 13 causes a gate 14
At the same time that the position data X _i of step i is output and at the same time the signal from the comparator 13 is taken into the step counter 16 of the main control unit 6, the value of the counter is updated from i to i + 1, and teaching is performed correspondingly. The data storage unit 3 selects the teaching data in step i + 1. In this embodiment in which the oscillator 10 is used to drive the addition switch 11, the phase angle increment value ΔC set in the phase angle increment value register 9 is specifically the reproduction cycle time set in the cycle time register 8. T _C, and the phase angle of one cycle recorded in the teaching data recording unit 3, that is, the phase angle of the final teaching point is θ CY.
And the oscillation frequency of the oscillator 10 is aH _z , it can be obtained by the equation ΔC = θCY / (T _C × a). The phase angle increment value ΔC is the oscillator 1
Oscillation period of 0, ie, is added at a rate of once a / a, the process proceeds speed reference phase angle theta _r becomes θCY / T _C. That is, the reference phase angle θ _r sequentially increases with the advance speed that decreases the reproduction cycle time of the preset work program as T _C increases.

In the present invention, a reference phase angle data input / output unit 17 having a data communication function represented by RS232C is added as a communication means with the outside (other control device). The reference phase angle data input / output unit 17 further transmits an external reference phase angle input unit 18 for inputting data received from the outside as an interrupt process and its own reference phase angle (value of the reference phase angle register 12) at regular time intervals. The reference phase angle output unit 19 is provided. The external reference phase angle input unit 18 passes the reference phase angle data input to the reference phase angle register preset unit 20 at any time, and the reference phase angle register preset unit 20 that receives the reference phase angle data inputs the reference phase angle data input to the reference phase angle register 12. Substitute the data. FIG. 3 shows a state in which the two control devices 2 and 102 are connected by the communication means 21. Both are the same controller, and the oscillation frequency of the oscillator and the cycle register have the same value. The reference phase angle output unit 19 of the first control device 2 of FIG.
Is connected to the external reference phase angle input unit 118 of the controller 102 of FIG. In this case, the first control device 2 is the master and the second control device 102 is the slave.

In operation, at the time of reproduction, a reference phase angle θ _r is calculated based on a reproduction cycle time T _C of a preset work program, which gradually increases at a progressive speed that decreases as the reproduction cycle time increases. The reference phase angle θ _r recorded in the phase angle register 12 and the teaching phase angle data θ _i sent from the teaching data recording unit 3 are compared by the comparator 13, and the reference phase angle θ _r is the phase angle data θ _i. When the value exceeds, the signal is output, the gate 14 is opened, and the teaching position data X _i is output to the servo amplifier unit 7.

The reference phase angle θ _{r of} the first controller 2
Of the phase angle control unit 105 of the control device 102 via the external reference phase angle data input / output unit 118 of the second control device 102 by the external line 21 via the reference phase angle data input / output unit 17 of the control device 2. The reference phase angle of the reference phase angle register 112 is substituted, and the reference phase angle register value of the first control device 2 is output to the second control device 102 as a master at regular time intervals. In the control device 102, the reference phase angle register value of the control device 2 that is input at fixed time intervals is substituted into the reference phase angle register of its own as interrupt processing at every input, and is substituted into the reference phase angle θ _r . Teaching data recording unit 103
When the reference phase angle θ _r advances from the teaching phase angle, the teaching position data of the second robot (not shown) is output to its own servo amplifier section. Therefore, the first control device 2 and the second control device 102
_Are controlled by the same reference phase angle θ _r , and the first robot 1
Operates in synchronism with the robot of the second controller 102.

Now, assuming that the reference phase angle data output interval from the reference phase angle output section 19 is a second, the second controller 10
The second reference phase angle register 112 is replaced with the data of the reference phase angle register 12 of the first controller 2 every a second. Further, assuming that the oscillation cycle of the oscillator 10 in FIG. 2 (ON / OFF cycle of the addition switch 11 in FIG. 2) is b seconds, the relation of a> b is assumed. By doing so, in the control device 102, addition of a / b times (truncated integer value when decimal point is present) is added during replacement of the reference phase angle register value every a seconds. It is performed by the phase angle increment value register 9, the oscillator 10, and the addition switch 11. This state is shown in FIG.

The reason for doing this is that the reference phase angle data output interval a second is shortened because the processing time required for the communication means typified by RS232C is longer than that for the simple register addition processing. As the load on the CPU tends to increase, the reference phase angle data output interval a second is set to be longer than the phase angle register addition period b second in order to reduce the load. Then, interpolation is performed by adding the value of the phase angle increment value register obtained by its own cycle time register to the phase angle register at a smaller interval of b seconds between the a seconds.

Essentially, in a plurality of control devices, if the values set in the cycle time register 8 of FIG. 2 are the same, the oscillation frequency of the oscillator 10 is the same, and the addition start of the phase angle register is the same, the plurality of control devices are the same. The reference phase angle register of should always show the same value, but the oscillation frequency of the oscillator often contains some errors due to individual differences,
A slight deviation occurs in the addition interval of the reference phase angle register between different control devices, and this deviation is gradually integrated. As a result, the reference phase angle register value is deviated between different control devices, which leads to the desynchronization of the robot. However, in the present invention, even in two different phase angle registers that add at b second and b'second intervals,
Since one master phase angle register value is replaced with the other reference phase angle register value at a-second intervals, the addition error can be reset at a-second intervals, and the phase angle registers can be synchronized even between different control devices. As a result, it is possible to synchronize a plurality of robots controlled by different control devices.

More specifically, in FIG. 4, the upper stage is a graph of the reference phase angle register value of the first controller 2, and the lower stage is the second graph.
3 is a graph of a reference phase angle register value of the control device 102 of FIG. The case where the addition cycle of each addition switch of the control device 2 and the control device 102 is b seconds and b ′ seconds (b <b ′) is shown. In the upper stage, 10 scales are added every b seconds (10 scales), and in the lower stage, 10 scales are added every b'seconds (12 scales), so at time T1, the values of both reference phase angle registers are different. ing. However, immediately after that, since the reference phase angle register value was output from the control device 2, the control device 102
The reference phase angle register of is replaced, and at time T2, both reference phase angle register values match. By repeating this operation every a second cycle, the reference phase angle register 112 of the control device 102 becomes the reference phase angle register 12 of the control device 2.
Will be synchronized with. The dotted line in the lower graph is a
The reference phase angle register value when the replacement of the reference phase angle register value of the second cycle has not occurred.

Although FIG. 3 shows the connection of two control devices, when synchronizing more robots, the third controller (not shown) of the reference phase angle output unit of the second control device 102 is used. By connecting to the external reference phase angle input section of the control device, it is possible to synchronize virtually an unlimited number of robots.

[0020]

As described above, according to the present invention, there is provided a method of synchronizing an industrial robot, which enables a plurality of robots controlled by a plurality of control devices to always operate in synchronization with each other. There is no need for an interlock signal for interlocking between robots as in the past. As a result, the conventional interlock system eliminates the need for repeating the "operation" and "waiting" operations, and enables synchronous operation by continuous operation. This applies not only to applications that are temporarily synchronized, such as when transferring workpieces between robots, but also when one robot holds the workpiece and the other robot continuously deburrs or seals the workpiece. It is possible to support applications that require various synchronization. Furthermore, since it is possible to synchronize a virtually unlimited number of robots, it has become possible to synchronize dozens or hundreds of robots in the same production line. Moreover, if the setting of the reproduction cycle time is changed, the advancing speed of the reference phase angle is changed, so that the cycle time of the synchronous operation of a plurality of robots can be freely changed without modifying the teaching data. It became a thing.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a control device for a first robot used in a synchronous control method for an industrial robot according to an embodiment of the present invention.

FIG. 2 is a detailed block diagram showing an embodiment of the phase angle control unit in FIG.

FIG. 3 is a block diagram showing a connection relationship between the first robot of FIG. 1 and another robot.

FIG. 4 is an explanatory view showing the operation of the apparatus of FIG.

[Explanation of symbols]

 1. ． First robot 2, 102. ． Control device 3. ． Teaching data recording unit 5, 105. ． Phase angle control unit 7. ． Servo amplifier section (servo system) 17, 117. ． Reference phase angle data input / output unit 18, 118. ． External reference phase angle data input unit 19, 119. ． Reference phase angle data output unit 20, 120. ． Reference phase angle register preset unit 21. ． External wiring

Claims (3)

[Claims] 1. Each robot controlled by a plurality of control devices is taught position data and speed data at a plurality of points of a work program, and drives the servo system by using these teaching data at the time of reproduction to make a work program As the data relating to the speed of the work program, the phase angle that sequentially increases as the teaching point progresses is taught, and at the time of reproduction, the reproduction cycle time is increased based on the preset reproduction cycle time of the work program. Then, a reference phase angle that gradually increases at a decreasing advance speed is calculated, the reference phase angle is compared with the teaching phase angle, and the teaching position data is servoed when the reference phase angle advances from the teaching phase angle. A method for synchronizing an industrial robot of a playback type, which is adapted to output to a system, The reference phase angle of the first robot is the phase of the other robot via an external line via the reference phase angle data input / output unit of the first robot and the reference phase angle data input / output unit of another robot. A method for synchronizing an industrial robot, characterized in that a robot controlled by a plurality of control devices is synchronized by substituting the reference phase angle of an angle control unit. 2. The reference phase angle data input / output unit of the first robot inputs the reference phase angle of the first robot to an external reference phase angle input unit for inputting data received from the outside as an interrupt process. Then, the reference phase angle is transmitted from the reference phase angle output unit of the first robot at regular intervals, and the reference phase angle is input to the external reference phase angle input unit of the another robot through the external line. The reference phase angle is preset to the reference phase angle register preset section of the robot, and the reference phase angle register preset section that receives the reference phase angle substitutes the reference phase angle for the reference phase angle of the phase angle control section of the another robot. The method for synchronizing an industrial robot according to claim 1, characterized in that. 3. The method for synchronizing an industrial robot according to claim 1, wherein the reference phase angle of the first robot and the reference phase angle of the other robot before substitution are different. ..