JP6879284B2 - Anomaly detection device, anomaly detection method, and anomaly detection system - Google Patents

Description

The present invention relates to an abnormality detection device or the like that detects an abnormality in an air cylinder.

An abnormality detection device that detects the presence or absence of an abnormality in an air cylinder that executes various operations by driving is known as a prior art. For example, in Patent Document 1, a failure of the device is diagnosed based on the amount of fluctuation with respect to standard data of the time difference from when the drive source of the device is switched on and off until the detection signal changes according to the operating state of the device. The system is disclosed.

Japanese Unexamined Patent Publication No. 2002-297237

However, the prior art as described above does not consider that the operating time of the drive source of the apparatus fluctuates due to factors other than the failure. For example, fluctuations in operating time when the ambient temperature changes are not taken into consideration. Therefore, there is a possibility that the fluctuation of the operating time due to the change in the ambient temperature is erroneously determined as an abnormality of the device.

One aspect of the present disclosure has been made in view of the above-mentioned problems, and realizes a highly convenient abnormality detection device and the like capable of appropriately detecting an abnormality of an air cylinder in consideration of a change in ambient temperature. can do.

The present invention employs the following configuration in order to solve the above-mentioned problems.

That is, the abnormality detection device according to one aspect of the present disclosure is an abnormality detection device that detects an abnormality in an air cylinder having a piston, and operates to acquire an extrusion time required for pushing out the piston and a pullback time required for pulling back. A time acquisition unit and an abnormality detection unit that detects the presence or absence of an abnormality in the air cylinder by comparing the extrusion time and the pullback time with their respective standard times are provided. On a two-dimensional plane having the extrusion time as the horizontal axis and the pullback time as the vertical axis, a measurement point corresponding to the extrusion time and the pullback time newly acquired by the operation time acquisition unit is set as the extrusion time. When plotted together with a reference point indicating the standard time and the standard time of the pullback time, the distance from the reference point is equal to or greater than the first distance, and the extrusion time is smaller than the predetermined temperature straight line indicating the temperature change of the reference point. When the measurement point is plotted within the abnormality range set on the side where the pullback time is large and avoiding the predetermined temperature straight line, the abnormality of the air cylinder is detected.

According to this configuration, the abnormality detection device can detect an abnormality in the air cylinder based on the positional relationship between the measurement point and the reference point in the two-dimensional plane. For example, by setting an abnormal range in a region where measurement points are not plotted due to changes in the ambient temperature of the air cylinder, it is possible to distinguish between changes in measurement points (normal changes) due to temperature changes and abnormalities in the air cylinder. Can be detected. Therefore, it is possible to realize a highly convenient abnormality detection device that can detect an abnormality of an air cylinder in consideration of a change in ambient temperature without using an additional member such as a pressure sensor or a temperature sensor.

In the abnormality detection device according to the one side surface, the abnormality detection unit uses the reference point in the two-dimensional plane where both the extrusion time and the pullback time are equal to or longer than the reference point in the predetermined temperature straight line. The angle when rotated counterclockwise around the reference point until it overlaps the line segment connecting the point and the measurement point is greater than 0 ° and less than 180 °, from the first threshold value to the first threshold value. It may be one condition for determining that the air cylinder is abnormal that it is between the second threshold value, which is larger and less than 180 °. According to this configuration, it is possible to appropriately detect an abnormality in the air cylinder caused by an abnormality in the packing.

In the abnormality detection device according to the one side surface, in the two-dimensional plane, a region less than the first distance from the reference point and a region on the side where the extrusion time is larger and the pullback time is smaller than the predetermined temperature straight line The air cylinder is set in a normal region indicating that the air cylinder is normal, and even if the abnormality detection unit determines that the air cylinder is normal when the measurement points are plotted in the normal region. Good. According to this configuration, the measurement point does not move to the side where the extrusion time is longer and the pullback time is shorter than the predetermined temperature straight line due to the abnormality of the packing. Therefore, according to this configuration, it is possible to avoid erroneously determining that the air cylinder is abnormal based on the change in the measurement point due to other factors.

In the abnormality detection device according to the one aspect, the abnormality detection unit is in the air cylinder as long as the angle is between the first threshold value and the third threshold value which is equal to or more than the first threshold value and less than the second threshold value. It may be determined that the piston packing is abnormal, and if the angle is between the third threshold value and the second threshold value, it may be determined that the rod packing is abnormal in the air cylinder. According to this configuration, the abnormality detecting device can distinguish and detect the type of abnormality according to the angle formed by the line segment connecting the reference point and the measurement point with the predetermined temperature straight line on the two-dimensional plane.

The abnormality detection device according to the one side surface further includes a reference point setting unit for setting the coordinates of the reference point in the two-dimensional plane, and the reference point setting unit has the angle in the two-dimensional plane. When the measurement point is plotted in the reset area set to the area where the distance is less than one threshold or larger than the second threshold and the distance is greater than or equal to the second distance, the coordinates of the reference point are reset. May be good. According to this configuration, if a reference point that is not suitable for detecting an abnormality is set, the reference point can be reset. For example, if the reference point moves due to a temperature change rather than an abnormality in the air cylinder, the reference point can be reset according to the changed temperature. Thereby, the abnormal state and the normal state can be appropriately discriminated.

In the abnormality detection device according to the one side surface, the second distance is less than the first distance, and the reference point setting unit has the angle less than the first threshold value or larger than the second threshold value in the two-dimensional plane. If the distance is equal to or greater than the second distance, the coordinates of the reference point may be reset. According to this configuration, if a reference point that is not suitable for detecting an abnormality is set, the reference point can be reset. For example, when the ambient temperature changes, it becomes easy to reset the reference point according to the temperature change. Since the abnormality detection and the determination of the resetting of the reference point can be performed using individual threshold values, the reference point can be reset at an earlier timing.

The abnormality detection system according to one aspect of the present disclosure controls an abnormality detection device according to the one aspect, one or more air cylinders having pistons, and a gas supplied to the one or more air cylinders by a solenoid valve. It includes a manifold and a control device that controls the opening and closing of the solenoid valve.

The abnormality detection method according to one aspect of the present disclosure is an abnormality detection method for detecting an abnormality in an air cylinder having a piston, and an operation time acquisition for acquiring an extrusion time required for pushing out the piston and a pullback time required for pulling back. It has a step and an abnormality detection step for detecting the presence or absence of an abnormality in the air cylinder by comparing the extrusion time and the pullback time with their respective standard times. On a two-dimensional plane with the extrusion time as the horizontal axis and the pullback time as the vertical axis, the extrusion time is standardized by setting the measurement points newly acquired by the operating time acquisition unit according to the extrusion time and the pullback time. When plotted together with a reference point indicating the standard time of time and pullback time, the distance from the reference point is equal to or greater than the first distance, and the extrusion time is smaller than the predetermined temperature straight line indicating the temperature change of the reference point. When the measurement point is plotted within the abnormality range set on the side where the pullback time is large and avoiding the predetermined temperature straight line, the abnormality of the air cylinder is detected.

According to one aspect of the present invention, it is possible to realize a highly convenient abnormality detection device or the like that can appropriately detect an abnormality in an air cylinder in consideration of a change in ambient temperature.

It is a block diagram which shows the outline of the main part structure of the abnormality detection system of one aspect of this disclosure. It is a schematic diagram which shows the outline of the air cylinder of one aspect of this invention, (a) shows the outline of an air cylinder, and (b) shows the definition of extrusion time and pull-back time in an air cylinder. An example of a packing abnormality in an air cylinder on one side of the present invention, (a) shows a packing abnormality in an extrusion process, and (b) shows a packing abnormality in a pulling process. It is a schematic diagram which shows an example of the two-dimensional plane used in the abnormality detection apparatus of one aspect of this invention, with the extrusion time as the horizontal axis and the pullback time as the vertical axis. It is a graph which shows the change of the extrusion time and the pull-back time when the ambient temperature of an air cylinder changes from 10 degreeC to 40 degreeC in the abnormality detection device of one aspect of this invention. In the abnormality detection device of one aspect of the present invention, it is a graph which shows the change of extrusion time and pull-back time when packing abnormality occurs, (a) shows the case of piston packing abnormality, (b) is a rod. The case of abnormal packing is shown. It is a flowchart which shows an example of the processing executed by the abnormality detection apparatus of one aspect of this invention, (a) shows the flow of the initial setting processing, (b) shows the flow of the monitoring processing which monitors the operation of an air cylinder. .. The flow of the reference point update process called from FIG. 7B is shown. It is a schematic diagram which shows the outline which determines whether or not the reference value is reset using two threshold values in the abnormality detection device of one aspect of this invention. A specific example of the two-dimensional plane used in the abnormality detection device of one aspect of the present invention is shown. It is a schematic diagram which shows the example which the 1st distance changes according to the combination of extrusion time and pull-back time.

§1 Configuration example (configuration of abnormality detection system)
FIG. 1 is a block diagram showing an outline of a configuration of a main part of the abnormality detection system 100 on one aspect of the present disclosure. The abnormality detection system 100 includes a compressor 1, a regulator 2, an discharge port 3, a manifold 4, an air cylinder 5, an abnormality detection device 6, and a display device 7. In FIG. 1, the solid line shows the flow of data, and the dotted line shows the flow of gas.

The abnormality detection system 100 is a system in which the abnormality detection device 6 detects at least one abnormality of one or more air cylinders 5 driven by the inflow and outflow of gas. When the abnormality detection device 6 detects an abnormality in the air cylinder 5, the abnormality detection device 6 notifies the user of the abnormality by using the display device 7. A gas pressurized by the compressor 1 and adjusted in pressure by the regulator 2 is supplied to the air cylinder 5 as the solenoid valve provided in the manifold 4 opens and closes. Further, from the air cylinder 5, unnecessary gas is discharged from the discharge port 3 as the solenoid valve opens and closes. Since the opening and closing of the solenoid valve in the manifold 4 is controlled by the abnormality detecting device 6, the abnormality detecting device 6 also functions as a control device for controlling the drive in one or more air cylinders 5.

The compressor 1 can pressurize the gas and supply it to the regulator 2. The regulator 2 is a regulator capable of adjusting the pressure of the gas supplied from the compressor 1 to a desired value and then supplying the pressure to the manifold 4. The discharge port 3 can receive the gas that is no longer needed for adjusting the pressure inside the air cylinder 5 through the manifold 4 and discharge it to the outside.

The manifold 4 is a flow path provided with one or more solenoid valves that can be opened and closed under the control of the abnormality detection device 6. When the manifold 4 receives an instruction to open / close the solenoid valve from the control unit 61 of the abnormality detection device 6, the manifold 4 opens / closes the corresponding solenoid valve, and gas is transferred between the opened / closed solenoid valve and the cylinder 53 of the air cylinder 5 communicating with the solenoid valve. It can be made to flow in and out. One or more air cylinders 5 may be connected to the manifold 4, and a specific solenoid valve communicating with the specific air cylinder 5 may be opened and closed according to an instruction from the abnormality detection device 6.

The air cylinder 5 includes a sensor 51 and a cylinder 53, and the cylinder 53 includes a piston 531 and a rod 533, a piston packing 535, and a rod packing 537. The air cylinder 5 can slide the piston 531 arranged inside the cylinder 53 by allowing gas to flow in and out of the manifold 4. The air cylinder 5 may be connected to various mechanisms (not shown) at the other end of the rod 533 whose one end is connected to the piston 531 or may be operated according to the sliding of the piston 531.

When the sensor 51 detects that the piston 531 is located at the pull-back end position or the extrusion end position, which will be described later, inside the cylinder 53, the sensor 51 can notify the abnormality detection device 6. The sensor 51 may be, for example, a limit switch that indicates the position of the piston 531 by turning the switch ON / OFF.

The cylinder 53 is formed so as to have an inner wall surface formed in a cylindrical shape inside the air cylinder 5, and ports for gas inflow and outflow are provided in the vicinity of both ends. The cylinder 53 can adjust the internal gas pressure by allowing gas to flow in and out of the port as the solenoid valve in the manifold 4 opens and closes. One end of the cylinder 53 is closed, and the other end is provided with a hole corresponding to the size of the rod 533 so that the rod 533 can penetrate the cylinder 53.

The piston 531 is a plug-shaped member slidably arranged inside the cylinder 53, and a rod 533 is connected to one end side of the piston 531. Inside the cylinder 53, the piston 531 slides inside the cylinder 53 according to the difference in gas pressure in the internal region of the cylinder 53 facing the piston 531.

The rod 533 is a rod-shaped member whose one end is connected to one end side of the piston 531 and can move according to the sliding of the piston 531. The rod 533 is arranged so as to penetrate a hole provided at one end of the cylinder 53, and the amount of protrusion from the end of the cylinder 53 changes according to the sliding of the piston 531.

The piston packing 535 is a packing fixed to the piston 531 in order to prevent gas from moving between the internal regions of the cylinders 53 facing each other with the piston 531 in between. The piston packing 535 may be an O-ring formed of, for example, rubber or resin.

The rod packing 537 is fixed to one end of the cylinder 53 in order to prevent gas from moving to the outside through a gap between the rod 533 and the hole corresponding to the size of the rod 533 provided at one end of the cylinder 53. It is a packing that has been made. Similar to the piston packing 535, the rod packing 537 may be an O-ring formed of, for example, rubber or resin.

The abnormality detection device 6 is a device that detects an abnormality in the air cylinder 5 having the piston 531 and includes a control unit 61. The control unit 61 includes an operation time acquisition unit 611, a reference point setting unit 613, an abnormality detection unit 615, and an abnormality notification unit 617.

The control unit 61 controls each unit of the abnormality detection device 6 in an integrated manner. The control unit 61 can transmit an opening / closing instruction of the solenoid valve to the manifold 4 to open / close a specific solenoid valve of the manifold 4. The control unit 61 can receive a notification from the sensor 51 regarding the position of the piston 531 at the pull-back end position or the extrusion end position, which will be described later.

The operation time acquisition unit 611 operates the piston 531 including the extrusion time required for pushing out the piston 531 in the cylinder 53 of the air cylinder 5 and the pulling time required for pulling back based on the notification received from the sensor 51 by the control unit 61. You can get the time. More specifically, the operation time acquisition unit 611 acquires the time required for the piston 531 at the pullback end position, which will be described later, to move to the extrusion end position, which will be described later, as the extrusion time. Further, the time required for the piston 531 at the extrusion end position to move to the pullback end position is acquired as the pullback time. The operating time acquisition unit 611 transmits the acquired extrusion time and pullback time to the reference point setting unit 613 when setting or resetting the reference point, and transmits to the abnormality detection unit 615 in other cases. For example, if the update flag indicating whether or not to reset the reference point is ON, the operation time acquisition unit 611 sets the destination of the extrusion time and the pullback time to the reference point setting unit 613, and the update flag is OFF. For example, the abnormality detection unit 615 is used.

The reference point setting unit 613 sets the coordinates of the reference point in the two-dimensional plane with the extrusion time as the horizontal axis and the pullback time as the vertical axis, which is used by the abnormality detection unit 615 to detect the abnormality of the air cylinder 5. Can be reset). Here, the reference point is a point set on the two-dimensional plane according to the standard time of the extrusion time and the standard time of the pullback time. The details of the reference point will be described later.

The conditions under which the reference point setting unit 613 sets (resets) the coordinates of the reference point may be any. For example, when the measurement points corresponding to the extrusion time and the pullback time received from the operation time acquisition unit 611 are plotted on the two-dimensional plane described later, the measurement points are set on the reset area set on the two-dimensional plane. When is plotted, the coordinates of the reference point may be set (reset).

The abnormality detection unit 615 compares the extrusion time and the pull-back time of the piston 531 inside the cylinder 53 of the air cylinder 5 acquired by the operation time acquisition unit 611 with the respective standard times, so that the abnormality in the air cylinder 5 is abnormal. It is possible to detect the presence or absence of. When the abnormality notification unit 617 detects that an abnormality has occurred in the air cylinder 5, the abnormality notification unit 617 can notify the abnormality notification unit 617 of the abnormality. A specific example of abnormality detection by the abnormality detection unit 615 will be described later.

When the abnormality notification unit 617 detects that an abnormality has occurred in the air cylinder 5 in the abnormality detection unit 615, the abnormality notification unit 617 may transmit information regarding the abnormality to the display device 7 according to the notification received from the abnormality detection unit 615. it can. The abnormality notification unit 617 transmits information regarding the abnormality, for example, when the operating time fluctuates in the air cylinder 5 or when a packing abnormality is detected in the abnormality detection unit 615.

The display device 7 is a display that is communicably connected to the abnormality detection device 6. When the display device 7 receives the information related to the abnormality from the abnormality notification unit 617, the display device 7 can display the received information as an image. The display device 7 may be a device different from the abnormality detection device 6, or may be formed integrally with the abnormality detection device 6.

(Overview of air cylinder)
2A and 2B are schematic views showing an outline of an air cylinder 5 on one side of the present invention, FIG. 2A shows an outline of the air cylinder 5, and FIG. 2B shows an extrusion time in the air cylinder 5. And the definition of pullback time is shown.

An outline of the air cylinder 5 is shown in FIG. 2 (a). A cylindrical cylinder 53 is formed in the air cylinder 5, and both ends of the cylinder 53 allow gas to flow in and out of and out of the manifold 4 via a port (not shown). A piston 531 provided with a piston packing 535 is slidably provided inside the air cylinder 5, and an end portion of a rod 533 is connected to one end side of the piston 531. One end of the rod 533 penetrates a hole provided at the end of the cylinder 53, and a rod packing 537 is fixed around the hole. In the illustrated example, one end of the cylinder 53 is closed by a sealing member different from the cylinder 53, and the rod 533 penetrates a hole provided in the sealing member. However, if one end of the cylinder 53 is closed and the rod 533 penetrates the hole, the sealing member may not be used.

In the illustrated example, two sensors 51 are provided near the end of the cylinder 53. Here, in the internal region of the cylinder 53 partitioned by the piston 531 the region where the rod 533 does not exist is defined as the pull-back region, and the region where the rod 533 exists is defined as the extrusion region. Then, the step in which the pressure in the pull-back region becomes less than the pressure in the extrusion region and the piston 531 moves so as to compress the pull-back region is defined as the pull-back step, and the pressure in the pull-back region becomes larger than the pressure in the extrusion region. The step in which the piston 531 moves so as to compress the extrusion region is referred to as an extrusion step. That is, in the pulling step, the rod 533 is pulled back into the cylinder 53, and in the extrusion step, the rod 533 is pushed out of the cylinder 53.

In the pull-back step, the position of the piston 531 when the piston 531 compresses the pull-back region to the limit is set as the pull-back end position, and in the extrusion step, the position of the piston 531 when the piston 531 compresses the extrusion region to the limit. Is the extrusion end position. When the piston 531 is located at the pull-back end position or the push-out end position, the sensor 51 notifies the outside to that effect.

Definitions of extrusion time and pullback time in the air cylinder 5 are shown using FIG. 2 (b). In the illustrated example, the "extrusion end" and "return end" of the "cylinder operation" indicate the end of the extrusion process and the pullback process, respectively. "Input" "Enable", "extrude", and "pull back" are "available or not", "driven by extrusion of rod 533" for various mechanisms connected to the end of rod 533. "Whether or not there is" and "Whether or not it is being driven by pulling back the rod 533" are shown respectively. The "extrusion end position" and the "pullback end position" indicate whether or not the piston 531 is located at the extrusion end position and whether or not the piston 531 is located at the pullback end position, respectively.

In the abnormality detection system 100, the abnormality detection device 6 controls the manifold 4 from the state where the piston 531 is in the pull-back end position to start the extrusion process, move the piston 531 to the extrusion end position, and then move the piston 531 to the extrusion end position. The operating time required to start the pull-back process and move the piston 531 to the pull-back end position is set to one frame. Further, in one frame, the time required for the piston 531 at the pullback end position to move to the extrusion end position is defined as the extrusion time, and the time required for the piston 531 at the extrusion end position to move to the pullback end position. Is the pullback time.

(Specific example of packing abnormality)
FIG. 3 shows an example of a packing abnormality in the air cylinder 5 on one side of the present invention. FIG. 3A shows a packing abnormality in the extrusion process, and FIG. 3B shows a packing abnormality in the pulling process. Shown.

The packing abnormality in the extrusion process will be described with reference to FIG. 3A. In the extrusion step, by increasing the pressure of the gas in the pull-back region of the cylinder 53, the piston 531 slides so as to compress the extrusion region, and as a result, the pressure of the gas in the extrusion region increases. At this time, if the piston packing 535 cannot prevent the movement of gas between the pull-back region and the extrusion region due to aged deterioration or the like, a part of the gas in the extrusion region leaks to the pull-back region. Similarly, if the rod packing 537 cannot prevent the movement of gas between the extrusion region and the outside, a part of the gas in the extrusion region leaks to the outside. That is, when an abnormality occurs in either the piston packing 535 or the rod packing 537, a part of the gas in the extrusion region that repels the piston 531 that compresses the extrusion region leaks in the extrusion process, so that the extrusion time It will be shortened.

The packing abnormality in the pulling-back step will be described with reference to FIG. 3B. In the pull-back step, by increasing the pressure of the gas in the extrusion region of the cylinder 53, the piston 531 slides so as to compress the pull-back region, and as a result, the pressure of the gas in the pull-back region increases. At this time, if the piston packing 535 cannot prevent the movement of the gas between the pull-back region and the extrusion region, a part of the gas in the extrusion region leaks to the pull-back region. Similarly, if the rod packing 537 cannot prevent the movement of gas between the extrusion region and the outside, a part of the gas in the extrusion region leaks to the outside. That is, when an abnormality occurs in either the piston packing 535 or the rod packing 537, the piston 531 that compresses the pull-back region is pushed in the pull-back step, and a part of the gas in the extrusion region leaks out, so that the extrusion time Is extended.

(Anomaly detection using a two-dimensional plane)
FIG. 4 is a schematic view showing an example of a two-dimensional plane used in the abnormality detection device 6 on one side of the present invention, with the extrusion time as the horizontal axis and the pullback time as the vertical axis. In this configuration example, the abnormality detection unit 615 of the abnormality detection device 6 detects an abnormality of the air cylinder 5 by using a two-dimensional plane having the extrusion time as the horizontal axis and the pullback time as the vertical axis. More specifically, when the abnormality detection unit 615 newly receives the extrusion time and the pullback time from the operation time acquisition unit 611, the measurement points corresponding to the received extrusion time and the pullback time are set on the two-dimensional plane together with the reference point. Plot to. The abnormality detection unit 615 is set on the side where the distance from the reference point is equal to or greater than the first distance described later, and the extrusion time is smaller and the pullback time is longer than the predetermined temperature straight line representing the temperature change of the reference point. Moreover, when the measurement points are plotted within the set abnormality range while avoiding the predetermined temperature straight line, the abnormality of the air cylinder 5 is detected.

The reference point is a point on which the standard time of the extrusion time and the standard time of the pullback time, which are set by the reference point setting unit 613, are plotted on a two-dimensional plane. For the standard time of the extrusion time and the standard time of the pullback time, for example, the average value of the extrusion time and the average value of the pullback time when the air cylinder 5 in normal operation is operated a predetermined number of times or a predetermined time are set. To. The standard time of extrusion time and the standard time of pullback time may be set in advance or may be set each time as needed.

In the illustrated example, "high temperature" and "low temperature" indicate the direction in which the reference point moves in response to a change in the ambient temperature of the air cylinder 5. That is, the reference point moves on a predetermined temperature straight line passing through "high temperature" and "low temperature" in the two-dimensional plane according to the fluctuation of the ambient temperature of the air cylinder 5. The temperature straight line is a straight line showing the change of the reference point due to the ambient temperature. The higher the temperature, the lower the extrusion time and pullback time, and the lower the temperature, the higher the extrusion time and pullback time.

R _Th indicates the first distance to the boundary line of the range in which the abnormality detection unit 615 determines that the air cylinder 5 is normal regardless of the combination of the extrusion time and the pull-back time. Shown as the radius of the centered circle. R _p indicates the distance from the reference point to the measurement point. θ ₁ , θ ₂ , and θ ₃ indicate an abnormality range in which the abnormality detection unit 615 determines that the air cylinder 5 is abnormal. θ ₁ is greater than 0 ° and less than 180 °, and θ ₁ <θ ₂ <θ ₃ . The abnormal range is set avoiding a predetermined temperature straight line so that the reference point is not included in the abnormal range even if the ambient temperature changes.

The abnormality detection unit 615 is the reference point until the portion of the predetermined temperature straight line in which both the extrusion time and the pull-back time are equal to or longer than the reference point overlaps with the line segment connecting the reference point and the measurement point. _{Based on the angle θ p} when rotated counterclockwise around the air cylinder 5, the type of abnormality generated in the air cylinder 5 is distinguished.

The abnormality detection unit 615 determines that the piston packing 535 is abnormal in the air cylinder 5 if _{the distance R p} is _{larger than R Th} and the angle θ _p is between the first threshold value θ ₁ and the third threshold value θ _2. Then, if θ _p is between θ ₂ and the second threshold value θ ₃ , it may be determined that the rod packing 537 is abnormal in the air cylinder 5.

On the other hand, in the two-dimensional plane, the _{air cylinder 5 is normal in the region where the distance from the reference point is less than the first distance R Th} and the region on the side where the extrusion time is larger and the pullback time is smaller than the predetermined temperature straight line. It may be set as a normal area indicating that. At this time, the abnormality detection unit 615 may determine that the air cylinder 5 is normal when the measurement shop is plotted in the normal region.

The coordinates of the reference point may be reset by the reference point setting unit 613. For example, the reference point setting unit 613 is a resetting area in which the angle θ _p is less than the first threshold value θ ₁ or larger than the second threshold value θ ₃ and the distance R _p is set to a region greater than or equal to the second distance in the two-dimensional plane. If the measurement points are plotted, the coordinates of the reference points may be reset. Here, the second distance _{may have the same value as the first distance R Th} , or may have different values from each other. Further, the reset area may be at least partially overlapped with the normal area, or different areas may be set.

(Changes in extrusion time and pullback time due to changes in ambient temperature)
FIG. 5 is a graph showing changes in extrusion time and pullback time when the ambient temperature of the air cylinder 5 changes from 10 ° C. to 40 ° C. in the abnormality detection device 6 on one side of the present invention. In the illustrated example, the horizontal axis is the number of times the frame is executed (the number of reciprocations of the piston 531) described in FIG. 2B, and the vertical axis is the extrusion time and the pullback time together as the operation time.

As shown in the figure, as the number of times the frame is executed increases, both the extrusion time and the pullback time decrease. This is because the pressure of the gas newly flowing into the cylinder 53 rises as the ambient temperature of the air cylinder 5 rises from 10 ° C. to 40 ° C. As the pressure of the gas in the extrusion region and the pull-back region increases, the force that moves the piston 531 increases, so that both the extrusion time and the pull-back time are shortened.

(Changes in extrusion time and pullback time due to packing abnormality)
FIG. 6 is a graph showing changes in extrusion time and pullback time when a packing abnormality occurs in the abnormality detection device 6 on one aspect of the present invention, and FIG. 6A is a graph showing a piston packing abnormality. In FIG. 6, FIG. 6B shows a case where the rod packing is abnormal. In each figure of FIG. 6, the horizontal axis and the vertical axis are the same as those shown in FIG.

As shown in FIG. 6A, when there is an abnormality in the piston packing 535 in the abnormality detection device 6, the extrusion time is shortened and the pullback time is extended as the number of times the frame is executed increases. This is due to the reason explained with reference to each figure of FIG.

Further, as shown in FIG. 6B, when the rod packing 537 has an abnormality in the abnormality detection device 6, the extrusion time increases as the number of times the frame is executed increases, as in the case where the piston packing 535 has an abnormality. It will be shortened and the pullback time will be extended. This is also due to the reason explained with reference to each figure of FIG.

As shown in each figure of FIG. 6, when the piston packing 535 has an abnormality and the rod packing 537 has an abnormality in the abnormality detection device 6, the extrusion time is shortened and the pullback time is extended. .. However, since the rate of change differs depending on the type of abnormality, it is possible to distinguish between the piston packing abnormality and the rod packing abnormality. Therefore, in the two-dimensional plane shown in FIG. 4, the piston packing abnormality and the rod packing abnormality can be shown as different ranges.

§2 Operation example (flow of initial setting processing and monitoring processing)
7A and 7B are flowcharts showing an example of processing executed by the abnormality detection device 6 on one side of the present invention. FIG. 7A shows a flow of initial setting processing, and FIG. 7B shows an air cylinder. The flow of the monitoring process for monitoring the operation of 5 is shown.

First, the flow of the initial setting process in the abnormality detection device 6 will be described with reference to FIG. 7A. First, the control unit 61 of the abnormality detection device 6 operates the piston 531 of the air cylinder 5 by controlling the manifold 4. Then, the operation time acquisition unit 611 acquires the data of the operation time including the extrusion time and the pullback time based on the notification from the sensor 51 (S1).

After S1, the operation time acquisition unit 611 instructs the reference point setting unit 613 to set the reference point data, and the reference point setting unit 613 instructs the reference point setting unit 613 to set the standard time and the pullback time of the extrusion time from the operation time data according to the instruction. The standard time of is set, and these are set as the data of the reference point (S2).

After S2, the abnormality detection unit 615 plots the data of the reference point set by the reference point setting unit 613 on the two-dimensional plane, and further sets various threshold _{values such as the first distance R Th} and the angles θ _{1 to 3 (} S3). After that, the abnormality detection device 6 ends a series of processes.

Next, the flow of the monitoring process in which the abnormality detecting device 6 monitors the operation of the air cylinder 5 will be described with reference to FIG. 7B. When the extrusion process and the pull-back process are performed in the air cylinder 5, the sensor 51 notifies the movement of the piston 531 and the operation time acquisition unit 611 of the abnormality detection device 6 determines the extrusion time and the pull-back time based on the notification. Acquire the data of the including operation time (S11: operation time acquisition step). The operation time acquisition unit 611 further determines whether or not the update flag is ON (S12). If the update flag is ON (YES in S12), the process executes the reference point update process in S13 to reset the reference point data, and then proceeds to S14. On the other hand, if the update flag is not ON (NO in S12), the process proceeds directly to S14.

In S14, the abnormality detection unit 615 plots the reference point and the measurement point corresponding to the operation time data acquired in S11 on the two-dimensional plane, and calculates _{the distance R p} and the angle θ _{p described in FIG. 4 (} S14). Then, the abnormality detection unit 615 _{determines whether or not the distance R p calculated in S14 is equal to} or greater than the first distance R Th (S15: abnormality detection step). If it is determined that the distance is not equal to or greater than the first distance R _Th (NO in S15), the process proceeds to S11, and the processes of S11 to S15 are executed again. On the other hand, _{when it is determined that the distance is equal to or greater than the first distance R Th} (YES in S15), the abnormality notification unit 617 indicates that the operating time of the air cylinder 5 has changed based on the notification from the abnormality detection unit 615. Notify the user using.

After S16, the abnormality detection unit 615 _{determines whether or not the angle θ p} calculated in S14 is equal to or greater than the first threshold value θ ₁ and equal to or less than the second threshold value θ ₃ (S17: abnormality detection step). If theta _p is theta less than _1, or theta _p is determined to be greater than theta ₃ (NO in S17), the control unit 61 sets the update flag to ON (S18). After that, the process proceeds to S11, and the processes of S11 to S18 are executed again. On the other hand, _{when it is determined that θ p} is θ ₁ or more and θ ₃ or less (YES in S17), the abnormality detection unit 615 further determines whether or not _{θ p} is θ ₁ or more and less than the third threshold value θ _2. Judgment (S19: abnormality detection step).

When it is determined in S19 that θ _p is less than _{θ 1 or θ p} is θ ₂ or more (NO in S19), the abnormality detection unit 615 determines that the air cylinder 5 has a rod packing abnormality. Then, the abnormality notification unit 617 notifies the user of the rod packing abnormality of the air cylinder 5 by using the display device 7 based on the notification from the abnormality detection unit 615 (S20). On the other hand, _{when it is determined that θ p} is θ ₁ or more and _{less than θ 2} (YES in S19), the abnormality detection unit 615 determines that the air cylinder 5 has a piston packing abnormality. Then, the abnormality notification unit 617 notifies the user of the piston packing abnormality of the air cylinder 5 by using the display device 7 based on the notification from the abnormality detection unit 615 (S21).

(Flow of reference point update process)
FIG. 8 shows a flow of the reference point update process called from FIG. 7B. The reference point update process is called from S13 in the monitoring process shown in FIG. 7B, executes a series of processes, and then returns to the caller.

In the following description, the collection count indicates the number of times the reference point update process is called and the extrusion time and pullback time data are acquired in order to reset the coordinates of the reference point. In addition, the specified number of times shall be set to a sufficient number of times to calculate the standard time of extrusion time and pullback time using the acquired data of the plurality of extrusion time and pullback time. For example, if the specified number of times is 500, the reference point setting unit 613 calculates the standard time of extrusion time and the standard time of pullback time using 500 extrusion times and pullback times.

First, when the reference point update process is called, the reference point setting unit 613 determines whether or not the current collection count is equal to the designated number of times (S31). When it is determined that the number of times is not equal to the specified number of times (NO in S31), the control unit 61 causes the air cylinder 5 to execute the extrusion process and the pull-back process. Then, the operation time acquisition unit 611 acquires the data of the operation time including the extrusion time and the pullback time for a specified number of times according to the extrusion process and the pullback process, and stores the data in a storage unit (S32) (not shown). After that, the process proceeds to S34. On the other hand, when it is determined that the number of times is equal to the specified number of times (YES in S31), the reference point setting unit 613 uses the data of the operation time for the specified number of times stored in the storage unit so far to determine the extrusion time. Calculate the standard time for standard time and pullback time. The reference point setting unit 613 resets (overwrites) the reference point data using the calculated standard time of extrusion time and standard time of pullback time (S33). After that, the process proceeds to S35.

In S34, the reference point setting unit 613 increments the collection count (S34). After that, the process returns to the caller. Further, in S35, the reference point setting unit 613 sets the update flag to OFF (S35), and further updates the collection count to 0 (S36). After that, the process returns to the caller.

Through the above processing, the abnormality detection device 6 can detect an abnormality in the air cylinder 5 based on the positional relationship between the measurement point and the reference point in the two-dimensional plane. Further, the abnormality detection device 6 can detect the piston packing abnormality and the rod packing abnormality of the air cylinder 5 separately, and can reset the data of the reference point as necessary. Thereby, the abnormality of the air cylinder 5 can be detected in consideration of the change in the ambient temperature without using an additional member such as a pressure sensor or a temperature sensor.

In FIG. 7B, the anomaly detection device 6 has an angle θ _p less than the first threshold value θ ₁ or larger than the second threshold value θ ₃ and a distance R _p greater than or equal to the first distance R _{Th in the two-dimensional plane.} In some cases, the update flag was set to ON. That is, the configuration was such that the second distance for setting the reset area was equal to the first distance. However, for example, the condition for setting the update flag to ON may be further _refined by using the second distance R _{Th2 which is less than the first distance R Th.}

FIG. 9 is a schematic diagram showing an outline of determining whether or not to reset the reference value using two threshold values in the abnormality detection device of one aspect of the present invention. In the illustrated example, the position of the original reference point in the two-dimensional plane is shown as "original reference data", and the position of the reference point after resetting is shown as "reference data after update". Further, in the "original reference data", a circle whose radius centered on the reference point is the first distance R _Th is shown as an "abnormality detection circle", and the radius centered on the reference point is the second distance R _{Th 2} . A circle is shown as a "circle for updating the reference point".

_{The abnormality detection device 6 may use the first distance R Th} and the second distance R _Th 2 properly depending on the situation regarding the positional relationship between the reference point and the measurement point in the two-dimensional plane. The abnormality detection device 6 uses, for example, the first distance R _{Th when determining whether or not an abnormality has occurred in the air cylinder 5, and uses the second distance R Th} 2 when determining whether or not to reset the reference point. You may. Specifically, the abnormality detection device 6 sets the update flag to ON when the _{angle θ p} is less than the first threshold value θ ₁ or larger than the second threshold value θ ₃ and the distance R _p is the second distance R _{Th 2 or more.} You may. That is, the reference point setting unit 613 is set in a region _{where the angle θ p} is less than the first threshold value θ ₁ or larger than the second threshold value θ ₃ and the distance R _p is set to the second distance R _{Th 2} or more in the two-dimensional plane. When the measurement points are plotted in the setting area, the coordinates of the reference points may be reset. By determining the necessity of resetting the reference point using the second distance R _Th2 which is less than the first distance R _Th , the followability of the reference point to the change in the ambient temperature of the air cylinder 5 can be improved. ..

FIG. 10 shows a specific example of a two-dimensional plane used in the abnormality detection device 6 of one aspect of the present invention. In FIG. 10, similarly to FIG. 4, a predetermined temperature straight line based on the reference point is measured, and it can be seen that the measurement points are plotted in clearly different regions between the case of the piston packing abnormality and the case of the rod packing abnormality.

In the above description, the first distance R _Th on the two-dimensional plane is shown as a circle centered on the reference point, but the first distance R Th is not limited to this. FIG. 11 is a schematic view showing an example in which the first distance changes according to the combination of extrusion time and pullback time. In the illustrated example, the first distance R _Th is shown as an ellipse having a major axis a in a direction parallel to a predetermined temperature straight line and a minor axis b in a vertical direction. In this way, the normal region may be set in any way.

§3 Deformation example In the two-dimensional plane shown in FIG. 4, the regions showing the piston packing abnormality and the rod packing abnormality were adjacent to each other but did not overlap. However, the abnormality detecting device 6 may determine that both the piston packing abnormality and the rod packing abnormality have occurred near the boundary between the regions, and notify the display device 7 of the occurrence of the piston packing abnormality and the rod packing abnormality. .. As a result, when both the piston packing abnormality and the rod packing abnormality actually occur, it can be appropriately detected.

[Example of realization by software]
The control block of the abnormality detection device 6 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software.

In the latter case, the abnormality detection device 6 includes a computer that executes instructions of a program that is software that realizes each function. The computer includes, for example, one or more processors and a computer-readable recording medium that stores the program. Then, in the computer, the processor reads the program from the recording medium and executes it, thereby achieving the object of the present invention. As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, a "non-temporary tangible medium", for example, a ROM (Read Only Memory) or the like, a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) for expanding the above program may be further provided. Further, the program may be supplied to the computer via an arbitrary transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. It should be noted that one aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the above program is embodied by electronic transmission.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

100 Anomaly detection system 4 Manifold 5 Air cylinder 53 Cylinder 531 Piston 535 Piston packing 537 Rod packing 6 Anomaly detection device (control device)
611 Operating time acquisition unit 613 Reference point setting unit 615 Abnormality detection unit

Claims (8)

An abnormality detection device that detects an abnormality in an air cylinder having a piston.
An operation time acquisition unit that acquires the extrusion time required for pushing out the piston and the pullback time required for pulling back.
It is provided with an abnormality detection unit that detects the presence or absence of an abnormality in the air cylinder by comparing the extrusion time and the pullback time with their respective standard times.
The abnormality detection unit is
On a two-dimensional plane with the extrusion time as the horizontal axis and the pullback time as the vertical axis, the measurement points newly acquired by the operation time acquisition unit according to the extrusion time and the pullback time are set on the extrusion time. When plotted with a reference point indicating the standard time and the standard time of the pullback time
The distance from the reference point is set to a side that is equal to or greater than the first distance, and the extrusion time is smaller and the pullback time is longer than the predetermined temperature straight line representing the temperature change of the reference point, and the predetermined temperature straight line is avoided. An abnormality detection device that detects an abnormality in the air cylinder when the measurement points are plotted within the abnormality range set in the above. The abnormality detection unit is a line segment in the two-dimensional plane in which a portion of the predetermined temperature straight line in which both the extrusion time and the pullback time are equal to or longer than the reference point connects the reference point and the measurement point. The angle when rotated counterclockwise about the reference point until it overlaps with the first threshold is greater than 0 ° and less than 180 °, and the angle is greater than the first threshold and less than 180 °. The abnormality detection device according to claim 1, wherein the condition is that the air cylinder is within the threshold value as one condition for determining that the air cylinder is abnormal. In the two-dimensional plane, a region less than the first distance from the reference point and a region on the side where the extrusion time is larger and the pullback time is smaller than the predetermined temperature straight line indicate that the air cylinder is normal. It is set in the normal area and
The abnormality detection device according to claim 1 or 2, wherein the abnormality detection unit determines that the air cylinder is normal when the measurement points are plotted in the normal region. The abnormality detection unit is
If the angle is between the first threshold value and the third threshold value which is equal to or more than the first threshold value and less than the second threshold value, it is determined that the piston packing is abnormal in the air cylinder.
The abnormality detection device according to claim 2, wherein if the angle is between the third threshold value and the second threshold value, it is determined that the rod packing is abnormal in the air cylinder. Further, a reference point setting unit for setting the coordinates of the reference point in the two-dimensional plane is provided.
The reference point setting unit is set in a resetting region in which the angle is less than the first threshold value or larger than the second threshold value and the distance is set to a region equal to or larger than the second threshold value in the two-dimensional plane. The anomaly detection device according to claim 4, wherein when is plotted, the coordinates of the reference point are reset. The second distance is less than the first distance,
When the angle is less than the first threshold value or larger than the second threshold value and the distance is greater than or equal to the second distance in the two-dimensional plane, the reference point setting unit resets the coordinates of the reference point. The abnormality detection device according to claim 5. The abnormality detection device according to any one of claims 1 to 6.
With one or more air cylinders with pistons,
A manifold that controls the gas supplied to the one or more air cylinders by a solenoid valve,
An abnormality detection system including a control device for controlling the opening and closing of the solenoid valve. An abnormality detection method that detects an abnormality in an air cylinder having a piston.
An operation time acquisition step for acquiring the extrusion time required for pushing out the piston and the pullback time required for pulling back, and
It has an abnormality detection step of detecting the presence or absence of an abnormality in the air cylinder by comparing the extrusion time and the pullback time with their respective standard times.
In the abnormality detection step,
On a two-dimensional plane with the extrusion time as the horizontal axis and the pullback time as the vertical axis, the extrusion time and the measurement points newly acquired in the operation time acquisition step according to the extrusion time and the pullback time are set. When plotted with a reference point indicating the standard time of the standard time and the standard time of the pullback time
The distance from the reference point is set to a side that is equal to or greater than the first distance, and the extrusion time is smaller and the pullback time is longer than the predetermined temperature straight line representing the temperature change of the reference point, and the predetermined temperature straight line is avoided. An abnormality detection method for detecting an abnormality in the air cylinder when the measurement points are plotted within the abnormality range set in the above.

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