WO2013153607A1

WO2013153607A1 - Positioning device

Info

Publication number: WO2013153607A1
Application number: PCT/JP2012/059717
Authority: WO
Inventors: 孝浩矢木
Original assignee: 三菱電機株式会社
Priority date: 2012-04-09
Filing date: 2012-04-09
Publication date: 2013-10-17
Also published as: TW201341997A; JPWO2013153607A1

Abstract

In order to provide a positioning device with which machinery defects can be detected at an early stage without the need for large capacity memory, and with which machinery deterioration can be detected in order to serve as a warning, a positioning unit (100) is provided with: a memory (120); a positioning control unit (111) for calculating the positioning output of the subsequent control cycle in accordance with an accumulated pulse amount; and a defect-detection unit (112) which, during normal operation, measures the maximum value of the accumulated pulse amount and records the obtained maximum accumulated-pulse-amount value (121) in the memory (120), and which, during steady operation, calculates, on the basis of the maximum accumulated-pulse-amount value (121), a warning threshold value (123) which is greater than the maximum accumulated-pulse-amount value (121) and a defect-detection threshold value (122) which is greater than the warning threshold value (123), issues a warning notification when the accumulated pulse amount exceeds the warning threshold value (123) but does not exceed the defect-detection threshold value (122), and suspends the output of the positioning output when the accumulated pulse amount exceeds the defect-detection threshold amount (122).

Description

Positioning device

The present invention relates to a positioning device that performs positioning of a controlled machine.

A programmable controller (PLC) may be configured with a positioning unit (positioning device) that performs feedback loop control of a feedback pulse input from a servo motor included in a controlled machine. In addition, the positioning unit calculates the droop pulse amount of the deviation counter from the feedback pulse of the servo motor, and detects machine abnormalities during position control by the servo motor based on the comparison between the droop pulse amount and the allowable value. There is.

Here, since the allowable value for the droop pulse amount is calculated based on the specifications of the maximum speed of the servo motor, the difference between the droop pulse amount and the permissible value increases depending on the servo motor control contents, and abnormality detection is possible. There was a case to be late. Therefore, even if the position control is stopped after the positioning device detects an abnormality, there is a problem that the controlled machine is damaged.

In this regard, there has been proposed a technique for a positioning control device that stores a physical quantity related to normal operation and detects an abnormality by sequentially comparing the stored physical quantity with a physical quantity during regular work. (For example, see Patent Document 1, Patent Document 2, and Patent Document 3).

Japanese Patent Laid-Open No. 61-061790 JP 62-256007 A JP 60-238905 A

However, according to the technique of the above-mentioned Patent Document 1, the positioning control device stores all changes in the normal operation as a physical quantity, so that a large-capacity memory for storing the physical quantity is required separately. Further, according to the technique of Patent Document 2, the positioning control apparatus uses a time-consuming amount such as a dead time, a rise time, and an overshoot amount as a physical quantity for comparison. There was a problem that it could not be detected. According to the technique of Patent Document 3, since the positioning control device stores the relationship between the movement amount and the response time as a physical quantity for comparison, the physical quantity is similar to the positioning control device according to Patent Document 1. A large-capacity memory for storing the memory was necessary.

The present invention has been made in view of the above, and obtains a positioning device capable of detecting a machine abnormality at an early stage without requiring a large-capacity memory and detecting a machine deterioration as an alarm. With the goal.

In order to solve the above-described problems and achieve the object, the present invention provides a positioning output for the next control cycle according to a deviation between a storage unit, a positioning output for the controlled machine, and an encoder input from the controlled machine. In the normal operation, during the normal operation, the positioning control unit measures the maximum value of the deviation calculated for each control cycle, and records the maximum value obtained in the storage unit, during the steady operation, Based on the maximum deviation recorded in the storage unit, a first threshold value greater than the maximum value and a second threshold value greater than the first threshold value are calculated, and the positioning control unit Compares the deviation calculated for each control period with the first threshold value and the second threshold value, and the deviation exceeds the first threshold value and does not exceed the second threshold value. When the positioning control unit An abnormality detection unit that issues an alarm notification without stopping positioning output and stops output of positioning output by the positioning control unit when the deviation exceeds the second threshold value. And

In the positioning device according to the present invention, the storage unit does not need to record all the accumulated pulse amounts for each control cycle during operation, can detect an abnormality without requiring a complicated calculation, and can detect the abnormality. Since an alarm notification is output before detecting and stopping the operation of the controlled machine, it is possible to detect machine abnormalities at an early stage without requiring a large-capacity memory and to detect machine deterioration as an alarm. A positioning device that can be obtained can be obtained.

FIG. 1 is a block diagram illustrating a configuration of a PLC including a positioning unit according to an embodiment of the present invention. FIG. 2 is a flowchart for explaining the operation of the positioning unit during normal operation. FIG. 3 is a flowchart for explaining the operation of the positioning unit during the steady operation.

Hereinafter, an embodiment of a positioning device according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a block diagram illustrating a configuration of a PLC including a positioning unit according to an embodiment of the present invention. As shown in the figure, the PLC 1 is connected to a drive unit 300 and a controlled machine 400. The PLC 1 inputs a position command value (positioning output) for positioning the controlled machine 400 to the drive unit 300 for each control cycle of the arithmetic unit 110 described later. The drive unit 300 drives the movable part of the controlled machine 400 based on the input positioning output. The controlled machine 400 includes an encoder (not shown) that detects the current position of the movable part, and a position detection value (encoder input) by the encoder is input to the PLC 1. The drive unit 300 may be a servo amplifier, for example. Further, the movable part included in the controlled machine 400 may be a servo motor driven by a servo amplifier.

The PLC 1 includes a positioning unit 100 that calculates a positioning output using an encoder input as a feedback signal, and a CPU unit 200 that causes the positioning unit 100 to start positioning control in accordance with a request for starting position control from a user program. . The PLC 1 can be configured by mounting a desired functional unit in addition to the CPU unit 200 and the positioning unit 100. Examples of the functional unit that can be attached to the PLC 1 include a temperature controller device that outputs a temperature control signal based on a command from the CPU unit 200.

The positioning unit 100 includes a calculation unit 110, a memory (storage unit) 120, an encoder input circuit 130, a power source 140, and a positioning output circuit 150.

The power supply 140 generates electric power for operating the positioning output circuit 150.

The encoder input circuit 130 is a connection interface that receives an encoder input from the controlled machine 400, and transfers the received encoder input to the arithmetic unit 110.

The positioning output circuit 150 is a connection interface for supplying the drive unit 300 with the positioning output calculated by the calculation unit 110 (more precisely, the positioning control unit 111 described later). The positioning output circuit 150 can supply a positioning output to the drive unit 300 while power is supplied from the power supply 140. When the power supply from the power supply 140 is stopped, the positioning output circuit 150 stops supplying positioning output.

The calculation unit 110 is constituted by, for example, a CPU (Central Processing Unit). The calculation unit 110 implements functions as the positioning control unit 111 and the abnormality detection unit 112 by executing a predetermined program.

When the positioning control unit 111 receives a request for starting position control from the CPU unit 200, the positioning control unit 111 starts calculating positioning output. Here, the positioning control unit 111 can calculate the positioning output under feedback control using the encoder input as a feedback signal. Specifically, the positioning output is input to the positioning output circuit 150 and also to the deviation counter 113 provided in the positioning control unit 111. The deviation counter 113 calculates a deviation (a droop pulse amount) between the positioning output and the encoder input received by the encoder input circuit 130. The positioning control unit 111 calculates a positioning output to be output in the next control cycle according to the amount of accumulated pulses.

The abnormality detection unit 112 records the maximum value of the accumulated pulse amount of the deviation counter 113 during normal operation in the memory 120 as the accumulated pulse amount maximum value 121, and uses the accumulated pulse amount maximum value 121 to detect an abnormality during steady operation. A detection threshold value 122 and an alarm threshold value 123 are calculated.

The alarm threshold value 123 is set to a value larger than the accumulated pulse amount maximum value 121, and the abnormality detection threshold value 122 is set to a value larger than the alarm threshold value 123. The calculation method of the abnormality detection threshold value 122 and the alarm threshold value 123 may be any method as long as it is calculated using the accumulated pulse amount maximum value 121. For example, the abnormality detection unit 112 may obtain the abnormality detection threshold value 122 and the alarm threshold value 123 by multiplying the accumulated pulse amount maximum value 121 by a predetermined coefficient. Specifically, the abnormality detection unit 112 obtains a value obtained by multiplying the accumulated pulse amount maximum value 121 by 1.1 as an alarm threshold value 123 and multiplying the accumulated pulse amount maximum value 121 by 1.2. The detected value may be used as the abnormality detection threshold value 122. Further, the abnormality detection unit 112 may obtain the abnormality detection threshold value 122 and the alarm threshold value 123 by adding a predetermined value to the accumulated pulse amount maximum value 121.

Furthermore, the abnormality detection unit 112 compares the accumulated pulse amount calculated by the deviation counter 113 for each control cycle with each of the abnormality detection threshold value 122 and the alarm threshold value 123 during steady operation. When the accumulated pulse amount exceeds the abnormality detection threshold value 122, the abnormality detection unit 112 transmits a stop signal to the power supply 140 to stop the power supply 140 from supplying power to the positioning output circuit 150. Thereby, the operation of the controlled machine 400 can be stopped immediately. Even if the positioning output circuit 150 is broken, the controlled machine 400 can be stopped safely.

When the accumulated pulse amount does not exceed the abnormality detection threshold value 122 but exceeds the alarm threshold value 123, the abnormality detection unit 112 provides an alarm notification without issuing a stop signal to the power supply 140. To issue. When the CPU unit 200 receives the warning notification, the CPU unit 200 can output a warning to the user, for example, on a programmable display (not shown). When the positioning unit 100 has an output unit that displays an alarm for the user, such as an LED lamp, the output unit may output an alarm. Thereby, it becomes possible to notify the user of the abnormality without stopping the operation of the controlled machine 400.

It should be noted that the switching between the operation during normal operation and the operation during steady operation of the abnormality detection unit 112 is performed by a user operation, for example. The operation for switching may be executed, for example, via the above-described programmable display, or may be executed by providing the positioning unit 100 with a hardware switch and operating the hardware switch by the user. You may make it do. A programming tool is connected to store a user program in the CPU unit 200 and to set various parameters. You may enable it to perform the said switching operation using the said programming tool. That is, when the user designates the first operation mode, the abnormality detection unit 112 performs the operation during normal operation, and when the user designates the second operation mode, the abnormality detection unit 112 performs the operation during steady operation. To do.

Next, the operation of the positioning unit 100 according to the embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a flowchart for explaining the operation of the positioning unit 100 during normal operation.

As shown in FIG. 2, when the position control start from the CPU 200 is requested, the positioning control unit 111 starts the position control (step S1), and the deviation counter 113 calculates the accumulated pulse amount (step S2). . Note that the loop processing from step S2 to step S4 is executed every control cycle.

After the process of step S2, the abnormality detection unit 112 determines whether or not the accumulated pulse amount calculated by the deviation counter 113 is the maximum value of the accumulated pulse amount output from the start of position control (step S3). . When the droop pulse amount calculated in the process of step S2 is not the maximum value among the droop pulse amounts output from the start of position control (No in step S3), the process of step S2 is executed again. When the droop pulse amount calculated in the process of step S2 is the maximum value among the droop pulse amounts output from the start of position control (step S3, Yes), the abnormality detection unit 112 is recorded in the memory 120. The accumulated droop pulse amount maximum value 121 is overwritten with the droop pulse amount calculated in step S2 (step S4). If the droop pulse amount calculated in step S2 is the first value calculated after the start of position control, the memory 120 is in a state in which the droop pulse amount maximum value 121 is not recorded. The calculated value is recorded as the accumulated pulse amount maximum value 121. Thereafter, the process of step S2 is executed.

Note that the loop processing from step S2 to step S4 may be stopped by a command from the user. A command for stopping the loop processing may be input to the positioning unit 100 by a programmable display, a programming tool, or other input means.

FIG. 3 is a flowchart for explaining the operation of the positioning unit 100 during the steady operation. As shown in FIG. 3, when the position control start is requested from the CPU 200, the abnormality detection unit 112 first starts the abnormality detection threshold 122 based on the accumulated pulse amount maximum value 121 stored in the memory 120. The alarm threshold value 123 is calculated (step S11). The calculated abnormality detection threshold value 122 and alarm threshold value 123 are recorded in the memory 120, respectively.

Then, the positioning control unit 111 starts position control (step S12), and the deviation counter 113 calculates the accumulated pulse amount (step S13). In addition, the loop process of step S13, step S14, No, step S16, No is performed for every control period.

After the process of step S13, the abnormality detection unit 112 determines whether or not the accumulated pulse amount calculated in the process of step S13 exceeds the abnormality detection threshold value 122 (step S14). When the accumulated pulse amount exceeds the abnormality detection threshold value 122 (step S14, Yes), the abnormality detection unit 112 issues a stop signal to the power source 140 (step S15) and ends the operation. Since the power supply 140 that has received the stop signal stops the power supplied to the positioning output circuit 150, the positioning output circuit 150 stops outputting the positioning output.

When the accumulated pulse amount does not exceed the abnormality detection threshold value 122 (No at Step S14), the abnormality detection unit 112 determines whether or not the accumulated pulse amount exceeds the alarm threshold value 123 (Step S16). ). When the accumulated pulse amount exceeds the alarm threshold value 123 (step S16, Yes), the abnormality detection unit 112 outputs an alarm notification to the CPU unit 200 (step S17). Thereafter, the process of step S13 is executed. When the accumulated pulse amount does not exceed the alarm threshold 123 (No at Step S16), the process at Step S17 is skipped.

As described above, according to the embodiment of the present invention, the positioning unit 100 corresponds to the memory 120 and the deviation (the amount of accumulated pulses) between the positioning output for the controlled machine 400 and the encoder input from the controlled machine 400. The positioning control unit 111 that calculates the positioning output of the next control cycle, and the maximum value of the droop pulse amount that the positioning control unit 111 calculates for each control cycle during normal operation, The maximum amount 121) is recorded in the memory 120, and a first threshold value (alarm) that is larger than the maximum accumulated pulse amount 121 is determined based on the maximum accumulated pulse amount 121 recorded in the memory 120 during steady operation. Threshold value 123) and a second threshold value (abnormality detection threshold value 122) larger than the alarm threshold value are calculated, and the positioning control unit 111 The droop pulse amount calculated for each cycle is compared with the alarm threshold value 123 and the abnormality detection threshold value 122. The droop pulse amount exceeds the alarm threshold value 123, and the abnormality detection threshold value 122 is obtained. When the amount of accumulated pulses exceeds the threshold value 122 for abnormality detection, the positioning control unit 111 outputs the positioning output by the positioning control unit 111. Since the abnormality detecting unit 112 is stopped, the memory 120 does not need to record all the accumulated pulse amounts for each control cycle during operation, so the capacity of the memory 120 can be reduced. . In addition, since the positioning unit 100 detects an abnormality based on a simple comparison between the accumulated pulse amount and the abnormality detection threshold value 122, it does not require a complicated calculation, so that the abnormality can be detected early. it can. In addition, since the positioning unit 100 outputs an alarm notification before detecting an abnormality and stopping the operation of the controlled machine 400, the user can detect the abnormality before the controlled machine 400 is determined to be abnormal and stops. The deterioration of the control machine 400 can be recognized. That is, according to the embodiment of the present invention, it is possible to obtain a positioning device that can detect an abnormality of a machine at an early stage without requiring a large-capacity memory and can detect a deterioration of the machine as an alarm.

The positioning unit 100 is connected to the controlled machine 400 and outputs a positioning output calculated by the positioning control unit 111 to the controlled machine 400 at each control cycle, and the positioning output circuit 150 outputs the positioning output. A power supply 140 that supplies power for driving the circuit 150, and the abnormality detection unit 112 supplies power that the power supply 140 supplies to the positioning output circuit 150 when the accumulated pulse amount exceeds the abnormality detection threshold value 122. Since the positioning unit 100 is configured to be stopped, the positioning unit 100 can stop the operation of the controlled machine 400 even when the positioning output circuit 150 has failed when the abnormality detecting unit 112 detects an abnormality.

As described above, the abnormality detection unit 112 calculates the alarm threshold value 123 by multiplying the maximum accumulated pulse amount value 121 recorded in the memory 120 by the predetermined first constant to obtain the maximum accumulated pulse amount value. The abnormality detection threshold 122 may be calculated by multiplying 121 by a predetermined second constant. Similarly, the abnormality detection unit 112 calculates a warning threshold value 123 by adding a predetermined first constant to the accumulated pulse amount maximum value 121 recorded in the memory 120, and sets the accumulated pulse amount maximum value 121 to a predetermined value. The abnormality detection threshold value 122 may be calculated by adding the second constant. Thus, even when the operation pattern of the controlled machine 400 is changed, the user can automatically set the abnormality detection threshold value 122 and the alarm threshold value 123 by performing a test operation. It becomes possible.

In the above description, the positioning output is the position command value, and the encoder input is the position detection value of the current position. However, the speed command value is the positioning output and the speed detection value is the encoder input. You may do it.

As described above, the positioning device according to the present invention is suitable for application to a positioning device that performs positioning of a controlled machine.

DESCRIPTION OF SYMBOLS 100 Positioning unit 110 Calculation part 111 Positioning control part 112 Abnormality detection part 113 Deviation counter 120 Memory 121 Maximum amount of accumulated pulses 122 Abnormality detection threshold value 123 Alarm threshold value 130 Encoder input circuit 140 Power supply 150 Positioning output circuit 200 CPU Unit 300 Drive unit 400 Controlled machine

Claims

A storage unit;
A positioning control unit that calculates a positioning output of the next control cycle in accordance with a deviation between a positioning output for the controlled machine and an encoder input from the controlled machine;
During normal operation, the positioning control unit measures the maximum value of the deviation calculated for each control cycle, records the maximum value obtained in the storage unit, and is recorded in the storage unit during steady operation. Based on the maximum value of the deviation, the first threshold value larger than the maximum value and the second threshold value larger than the first threshold value are calculated, and the positioning control unit calculates each control cycle. When the deviation is compared with the first threshold value and the second threshold value, and the deviation exceeds the first threshold value and does not exceed the second threshold value, positioning by the positioning control unit An abnormality detection unit that issues an alarm notification without stopping output and stops output of positioning output by the positioning control unit when the deviation exceeds the second threshold value;
A positioning device comprising:
A positioning output circuit that is connected to the controlled machine and outputs a positioning output calculated by the positioning control unit to the control machine for each control cycle;
A power supply for supplying power for driving the positioning output circuit to the positioning output circuit;
With
The abnormality detection unit stops the power supplied from the power source to the positioning output circuit when the deviation exceeds the second threshold value.
The positioning device according to claim 1.
The abnormality detection unit calculates the first threshold value by multiplying the maximum value recorded in the storage unit by a first constant, and multiplies the maximum value by a second constant to perform the second step. Calculate the threshold,
The positioning device according to claim 1.
The abnormality detection unit calculates a first threshold value by adding a first constant to the maximum value recorded in the storage unit, adds a second constant to the maximum value, and adds the second constant. 2 Calculate the threshold value,
The positioning device according to claim 1.
The normal operation is when the first operation mode is designated, and the steady operation is when the second operation mode is designated.
The positioning device according to any one of claims 1 to 4, wherein the positioning device is characterized in that: