State monitoring system and state monitoring method

Abstract

To provide a state monitoring system capable of appropriately performing state monitoring of a pneumatic device.SOLUTION: A state monitoring system 1 for monitoring an operation state of a pneumatic device that operates with operation air as a drive source includes: a sensor for acquiring a physical quantity reflecting an operation state and a usage environment of the pneumatic device; and a state monitoring device 5 having a state monitoring program for converting a physical quantity (for example, a pressure value, an ambient temperature, and a time) acquired by the sensor to a performance value as data regarding a performance of the pneumatic device and an environment value as data regarding a usage condition of the pneumatic device, generating time-series data of the performance value and time-series data of the environment value, and calculating a correlation coefficient between the time-series data of the performance value and the time-series data of the environment value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a condition monitoring system and a condition monitoring method for monitoring the operating state of pneumatic equipment that operates using air pressure as a drive source. [Background technology]

[0002] Conventionally, as pneumatic devices that operate using air pressure as a drive source, there are known fluid pressure actuators equipped with sliding parts such as a piston and a valve, such as a double-acting cylinder and a change-over valve, which are used in robot arms in food factories, etc. For example, the inside of a double-acting cylinder is divided into a first pressure action chamber and a second pressure action chamber by a piston, and one end of a pipe that supplies or exhausts operation air is connected to each of the first pressure action chamber and the second pressure action chamber. The other end of the pipe is connected to a supply source of operation air via a change-over valve, and the piston reciprocates within the cylinder by switching between supplying air to the first pressure action chamber and supplying air to the second pressure action chamber by the change-over valve.

[0003] The operating state of the above-mentioned fluid pressure actuator is monitored by a monitoring device such as that disclosed in Patent Document 1. In addition, the deterioration degree of the fluid pressure actuator is also monitored, for example, as follows.

[0004] For example, by monitoring the performance values ​​of the fluid pressure actuator, such as the response time, the piston movement time, the thrust acting on the piston, and the air consumption of the operating air in the cylinder, it is possible to monitor the deterioration of the fluid pressure actuator.

[0005] For example, the piston movement time is calculated by detecting the start and stop of the piston movement with a sensor such as a cylinder switch. The movement time becomes longer as the deterioration of the fluid pressure actuator (for example, deterioration of the packing provided on the outer periphery of the piston) progresses. That is, as shown by the solid line waveform in FIG. 7, the movement time increases as the number of operations of the fluid pressure actuator increases. Therefore, a predetermined threshold T21 is set, and when the movement time exceeds the threshold T21 (time t21), it is determined that the fluid pressure actuator has deteriorated, and the fluid pressure actuator is repaired or parts are replaced, or the actuator is replaced with a new fluid pressure actuator (hereinafter, the repair or parts replacement of the fluid pressure actuator and the replacement with a new fluid pressure actuator are collectively referred to as maintenance). The threshold T21 may be a value determined according to the movement time required for the fluid pressure actuator, or may be a value that can be empirically determined as indicating that deterioration has progressed.

[0006] As described above, by monitoring the performance values ​​of the fluid pressure actuator, it is possible to perform maintenance of the fluid pressure actuator at an appropriate time. By performing maintenance at an appropriate time, it is possible to prevent abnormalities from occurring in the fluid pressure actuator, and in turn to prevent unintended shutdowns of a device that uses the fluid pressure actuator (such as a robot arm). It is also possible to use the fluid pressure actuator for as long as possible before it deteriorates, thereby reducing the frequency of maintenance. Furthermore, it is possible to minimize the energy loss required to drive the fluid pressure actuator by eliminating the increase in air consumption caused by air leakage that occurs with deterioration such as wear of the packing of the sliding parts. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-59549 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, since the performance values ​​of pneumatic equipment (fluid pressure actuators) can be affected by the conditions of use, it has been found that the timing for maintenance cannot be accurately determined by only monitoring the performance values. The specifics are explained below. The conditions of use include, for example, the temperature around the fluid pressure actuator (ambient temperature), the pressure of the operating air supplied to the fluid pressure actuator (supply pressure), the time the fluid pressure actuator is stopped (stop time), the operating cycle of the fluid pressure actuator, etc.

[0009] For example, grease is used in the sliding parts of the fluid pressure actuator to improve sliding properties, but the viscosity of the grease depends on the ambient temperature. When the viscosity of the grease changes, the sliding resistance changes, which may result in a longer movement time of the sliding parts (slower operation speed). In addition, when the operating environment becomes cold, the sliding parts of the pneumatic equipment lose their flexibility and become hard, which reduces the reaction force and may increase the amount of air leakage from the pneumatic equipment. For this reason, as shown by the dashed waveform in Figure 7, the movement time and air consumption may exceed the threshold value T21 even at a time point (time point t22) when degradation has not actually progressed. However, since the user of the fluid pressure actuator does not know whether the threshold value T21 is exceeded due to the operating conditions or the deterioration of the fluid pressure actuator, there is a possibility that maintenance may be performed at an appropriate time, for example, even if the deterioration has not actually progressed. In addition, since it is not known what change in the operating conditions caused the threshold value T21 to be exceeded, improvement by optimizing the operating conditions of the pneumatic equipment cannot be performed. Therefore, even if maintenance has been performed, there is a possibility that the same abnormality will occur again if the same operating conditions are used again.In addition, since there are various types of pneumatic equipment that are actually connected and various operating conditions for pneumatic equipment, it is difficult to know to what extent the performance values ​​will be affected by which operating conditions before starting to use the equipment.

[0010] The present invention has been made to solve the above problems, and has an object to provide a condition monitoring system and a condition monitoring method that are capable of appropriately monitoring the condition of pneumatic equipment. [Means for solving the problem]

[0011] In order to solve the above problems, a status monitoring system and a status monitoring method according to the present invention have the following configurations.

[0012] (1) A condition monitoring system for monitoring the operating state of a pneumatic device that operates using operating air as a drive source, comprising: a sensor for acquiring a physical quantity reflecting the operating state and usage environment of the pneumatic device; and monitoring means having a condition monitoring program for converting the physical quantity acquired by the sensor into a performance value, which is data related to the performance of the pneumatic device, and an environmental value, which is data related to the usage conditions of the pneumatic device, generating time series data of the performance value and time series data of the environmental value, and calculating a correlation coefficient between the time series data of the performance value and the time series data of the environmental value.

[0013] (2) In the condition monitoring system described in (1), it is preferable that the pneumatic device has a sliding part that is operated by the operating air, the performance values ​​include at least one of a response time of the pneumatic device, a movement time of the sliding part, a thrust force acting on the sliding part by the operating air, and an air consumption of the operating air in the pneumatic device, and the environmental values ​​include at least one of an ambient temperature that is the temperature around the pneumatic device, a supply pressure that is the pressure of the operating air supplied to the pneumatic device, a stop time that is the time the pneumatic device is stopped, and an operating period of the pneumatic device.

[0014] According to the above condition monitoring system, by calculating a correlation coefficient between time-series data of the performance value of a pneumatic device (for example, a fluid pressure actuator having a sliding part (for example, a piston) that is operated by operating air) and time-series data of the environmental value of the pneumatic device, it is possible to grasp whether or not the performance value is influenced by the environmental value. If the correlation is strong, it is clear that the performance value is influenced by the environmental value, and therefore, when an abnormality occurs in the performance value, it is possible to estimate the cause if it is due to the influence of a specific environmental value.

[0015] More specifically, if there is a strong correlation between at least one of the performance values ​​(hereinafter referred to as the specific performance value), such as the response time of pneumatic equipment, the movement time of the sliding part, the thrust force acting on the sliding part, and the air consumption of the operating air, and a specific combination of at least one of the environmental values ​​(hereinafter referred to as the specific environmental value), such as the ambient temperature, supply pressure, stop time, and operating cycle, then when an abnormality occurs in the specific performance value, it becomes possible to infer the cause that it may be due to the influence of the specific environmental value (for example, if the ambient temperature has a strong effect on movement time, then when an abnormality occurs in movement time, it becomes possible to infer the cause that it may be due to the influence of the ambient temperature).

[0016] (3) In the condition monitoring system described in (1) or (2), it is preferable that the condition monitoring program calculates a regression equation based on the time series data of the performance value and the time series data of the environmental value, and corrects the performance value using the regression equation.

[0017] According to the above condition monitoring system, the actual amount of fluctuation in the performance value can be obtained by correcting the performance value. This makes it possible to grasp the accurate performance of the pneumatic device excluding the influence of environmental values. Therefore, it is possible to appropriately monitor the condition of the pneumatic device.

[0018] (4) In the condition monitoring system described in (3), it is preferable that the condition monitoring program performs the correction on a combination of the environmental value and the performance value for which the absolute value of the correlation coefficient is 0.3 or more.

[0019] According to the above condition monitoring system, the performance values ​​are corrected by a regression equation, so that the performance of the pneumatic equipment can be accurately understood excluding the influence of environmental values. This makes it possible to accurately grasp the deterioration state of the pneumatic equipment. Therefore, it is possible to perform maintenance of the pneumatic equipment at an appropriate time, or to improve the pneumatic equipment by optimizing the operating conditions of the pneumatic equipment. In turn, it is possible to prevent unintended stopping of a device that uses pneumatic equipment (such as a robot arm). In addition, it is possible to use the pneumatic equipment for as long as possible until it deteriorates, thereby reducing the frequency of maintenance. Furthermore, it is possible to minimize the energy loss required to drive the pneumatic equipment.

[0020] Here, it is desirable to correct the performance value for an environmental value that has a strong correlation with the performance value. Specifically, when the absolute value of the correlation coefficient is 0.3 or more, it is determined that the correlation is strong, and correction is performed. More specifically, when the absolute value of the correlation coefficient between a specific performance value and a specific environmental value is 0.3 or more, correction is performed to remove the influence of the specific environmental value from the specific performance value (for example, when the absolute value of the correlation coefficient between the travel time and the ambient temperature is 0.3 or more, correction is performed to remove the influence of the ambient temperature from the travel time). The reason why correction is performed when the absolute value of the correlation coefficient is 0.3 or more is that the inventors have confirmed through experiments that an environmental value with an absolute value of the correlation coefficient smaller than 0.3 has a weak correlation with the performance value.

[0021] In order to solve the above problems, the condition monitoring method of the present invention has the following configuration.

[0022] (5) A condition monitoring method for monitoring the operating state of a pneumatic device that operates using operating air as a drive source, comprising the steps of: acquiring a performance value, which is data related to the performance of the pneumatic device, and an environmental value, which is data related to the use conditions of the pneumatic device; generating time series data of the performance value and time series data of the environmental value; and calculating a correlation coefficient between the time series data of the performance value and the time series data of the environmental value.

[0023] (6) In the condition monitoring method described in (5), it is preferable that the pneumatic device has a sliding part that is operated by the operating air, the performance values ​​include at least one of a response time of the pneumatic device, a movement time of the sliding part, a thrust force acting on the sliding part by the operating air, and an air consumption of the operating air in the pneumatic device, and the environmental values ​​include at least one of an ambient temperature that is the temperature around the pneumatic device, a supply pressure that is the pressure of the operating air supplied to the pneumatic device, a stop time that is the time during which the pneumatic device is stopped, and an operating period of the pneumatic device.

[0024] According to the above condition monitoring method, by calculating a correlation coefficient between time-series data of the performance value of a pneumatic device (for example, a fluid pressure actuator having a sliding part (for example, a piston) that is operated by operating air) and time-series data of the environmental value of the pneumatic device, it is possible to grasp the influence of the environmental value on the performance value. If the correlation is strong, it is clear that the performance value is influenced by the environmental value, and therefore, when an abnormality occurs in the performance value, it is possible to estimate the cause if it is due to the influence of a specific environmental value.

[0025] More specifically, if there is a strong correlation between at least one of the performance values ​​(hereinafter referred to as the specific performance value), such as the response time of pneumatic equipment, the movement time of the sliding part, the thrust force acting on the sliding part, and the air consumption of the operating air, and a specific combination of at least one of the environmental values ​​(hereinafter referred to as the specific environmental value), such as the ambient temperature, supply pressure, stop time, and operating cycle, then when an abnormality occurs in the specific performance value, it becomes possible to infer the cause that it may be due to the influence of the specific environmental value (for example, if the ambient temperature has a strong effect on movement time, then when an abnormality occurs in movement time, it becomes possible to infer the cause that it may be due to the influence of the ambient temperature).

[0026] (7) In the condition monitoring method described in (5) or (6), it is preferable to calculate a regression equation based on the time series data of the performance value and the time series data of the environmental value, and correct the performance value using the regression equation.

[0027] According to the above condition monitoring system, the actual amount of fluctuation in the performance value can be obtained by correcting the performance value. This makes it possible to grasp the accurate performance of the pneumatic device excluding the influence of environmental values. Therefore, it is possible to appropriately monitor the condition of the pneumatic device.

[0028] In the condition monitoring method described in (8) and (7), it is preferable that the correction is performed on a combination of an environmental value and a performance value for which the absolute value of the correlation coefficient is 0.3 or more.

[0029] According to the above condition monitoring method, the performance value is corrected by a regression equation, so that the accurate performance of the pneumatic equipment can be grasped excluding the influence of environmental values. This makes it possible to accurately grasp the deterioration state of the pneumatic equipment. Therefore, it is possible to perform maintenance of the pneumatic equipment at an appropriate time, or to improve the pneumatic equipment by optimizing the operating conditions of the pneumatic equipment. In turn, it is possible to prevent unintentional stopping of a device using the pneumatic equipment (such as a robot arm). In addition, it is possible to use the pneumatic equipment for as long as possible until it deteriorates, thereby reducing the frequency of maintenance. Furthermore, it is possible to minimize the energy loss required to drive the pneumatic equipment.

[0030] Here, it is desirable to correct the performance value for an environmental value that has a strong correlation with the performance value. Specifically, when the absolute value of the correlation coefficient is 0.3 or more, it is determined that the correlation is strong, and correction is performed. More specifically, when the absolute value of the correlation coefficient between a specific performance value and a specific environmental value is 0.3 or more, correction is performed to remove the influence of the specific environmental value from the specific performance value (for example, when the absolute value of the correlation coefficient between the travel time and the ambient temperature is 0.3 or more, correction is performed to remove the influence of the ambient temperature from the travel time). The reason why correction is performed when the absolute value of the correlation coefficient is 0.3 or more is that the inventors have confirmed through experiments that an environmental value with an absolute value of the correlation coefficient smaller than 0.3 has a weak correlation with the performance value. Effect of the Invention

[0031] According to the condition monitoring system and the condition monitoring method of the present invention, it is possible to appropriately monitor the condition of pneumatic equipment. [Brief description of the drawings]

[0032] [Figure 1] 1 is a diagram showing a schematic configuration of a status monitoring system according to an embodiment of the present invention; [Diagram 2] 11 is a table showing an example of time-series data of performance values ​​and environmental values. [Diagram 3] (a) is a graph of the time series data of travel time among the time series data of the performance values ​​shown in Figure 2. (b) is a graph of the corrected value of the time series data of travel time. [Figure 4] Graph (a) shows the correlation between time series data of travel time and time series data of ambient temperature. Graph (b) shows the correlation between time series data of travel time and time series data of supply pressure. Graph (c) shows the correlation between time series data of travel time and time series data of stop time. [Diagram 5] (a) is a graph of the time series data of maximum thrust from the time series data of the performance values ​​shown in Figure 2. (b) is a graph of the time series data of travel time corrected by one environmental value. (c) is a graph of the corrected value by multiple regression of the time series data of travel time. [Figure 6] Graph (a) shows the correlation between time series data of maximum thrust and time series data of ambient temperature. Graph (b) shows the correlation between time series data of maximum thrust and time series data of supply pressure. Graph (c) shows the correlation between time series data of maximum thrust and time series data of stoppage time. [Figure 7] 1 is a graph showing the relationship between the performance value (number of operations) of a fluid pressure actuator and the number of operations. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] An embodiment of a status monitoring system 1 of the present invention will be described in detail with reference to the drawings. Fig. 1 is a diagram showing a schematic configuration of a status monitoring system 1 according to this embodiment. The status monitoring system 1 is a system for monitoring the operating status of a fluid pressure actuator 10 (an example of a pneumatic device).

[0034] <Fluid pressure actuators> First, there will be described the configuration of the fluid pressure actuator 10. The fluid pressure actuator 10 includes a double-acting cylinder 101, a piston 102 (an example of a sliding portion), and an operating rod 105 as main components, as shown in FIG.

[0035] The piston 102 is slidably held inside the double-acting cylinder 101. The direction in which the piston 102 slides is, for example, along the longitudinal direction of the double-acting cylinder 101, which is the left-right direction in FIG. 1. The piston 102 divides the interior of the double-acting cylinder 101 into a first pressure application chamber 103 and a second pressure application chamber 104. An operating rod 105 is connected to the end face of the piston 102 on the second pressure application chamber 104 side. The operating rod 105 penetrates through the end (second end 101b) on the second pressure application chamber 104 side of both longitudinal ends of the double-acting cylinder 101, and extends to the outside of the double-acting cylinder 101.

[0036] Of both longitudinal ends of the double-acting cylinder 101, the end (first end 101a) on the side of the first pressure application chamber 103 is connected to one end of a first pipe 11 for supplying or discharging operating air. The first pipe 11 connected to the first end 101a is in communication with the first pressure application chamber 103 through an internal flow path of the double-acting cylinder 101. The other end of the first pipe 11 is connected to a first connection port 131 of the switching valve 13.

[0037] One end of a second pipe 12 for supplying or discharging operating air is connected to a second end 101b of the double-acting cylinder 101. The second pipe 12 connected to the second end 101b communicates with a second pressure application chamber 104 through an internal flow path of the double-acting cylinder 101. The other end of the second pipe 12 is connected to a second connection port 132 of the switching valve 13.

[0038] A flow rate adjustment unit 14A consisting of a check valve 141A and a flow rate adjustment valve 142A is provided on the first pipe 11. In addition, a flow rate adjustment unit 14B consisting of a check valve 141B and a flow rate adjustment valve 142B is provided on the second pipe 12.

[0039] The switching valve 13 has an input port 133 for inputting operation air to the switching valve 13. One end of an air supply pipe 15 is connected to the input port 133, and the other end of the air supply pipe 15 is connected to a supply source 16 of the operation air.

[0040] The switching valve 13 is a double solenoid type electromagnetic valve, and includes a first solenoid 134A and a second solenoid 134B. The first solenoid 134A and the second solenoid 134B are electrically connected to the control controller 2, which will be described later. Therefore, the control controller 2 can give an electric signal to the first solenoid 134A or the second solenoid 134B, which drives a valve body (not shown) inside the switching valve 13. This will be described in more detail below.

[0041] When an electric signal is applied to the first solenoid 134A, the valve element of the switching valve 13 is attracted toward the first solenoid 134A. As a result, the input port 133 and the first connection port 131 communicate with each other, and the second connection port 132 communicates with the outside of the switching valve 13.

[0042] By connecting the input port 133 to the first connection port 131, the operation air input from the supply source 16 to the switching valve 13 is output from the first connection port 131 to the first piping 11. The operation air output to the first piping 11 flows through the first piping 11, and is supplied to the first pressure application chamber 103 of the double-acting cylinder 101.

[0043] When the operation air is supplied to the first pressure application chamber 103, the pressure inside the first pressure application chamber 103 rises and the piston 102 is pressed. This causes the piston 102 to move toward the second end 101b. As the piston 102 moves toward the second end 101b (in the push direction), the operation air supplied to the second pressure application chamber 104 is exhausted from the second pressure application chamber 104. The operation air exhausted from the second pressure application chamber 104 flows into the switching valve 13 via the second piping 12 and the second connection port 132. At this time, since the second connection port 132 is in communication with the outside of the switching valve 13, the operation air that has flowed into the switching valve 13 is discharged to the outside.

[0044] On the other hand, when an electric signal is given to the second solenoid 134B, the valve element of the switching valve 13 is attracted toward the second solenoid 134B. As a result, the input port 133 and the second connection port 132 communicate with each other, and the first connection port 131 communicates with the outside of the switching valve 13.

[0045] By connecting the input port 133 to the second connection port 132, the operation air input from the supply source 16 to the switching valve 13 is output from the second connection port 132 to the second piping 12. The operation air output to the second piping 12 flows through the second piping 12, and is supplied to the second pressure application chamber 104 of the double-acting cylinder 101.

[0046] When the operation air is supplied to the second pressure application chamber 104, the pressure inside the second pressure application chamber 104 rises, and the piston 102 is pressed. This causes the piston 102 to move toward the first end 101a (in the pull direction). As the piston 102 moves toward the first end 101a, the operation air supplied to the first pressure application chamber 103 is exhausted from the first pressure application chamber 103. The operation air exhausted from the first pressure application chamber 103 flows into the switching valve 13 via the first piping 11 and the first connection port 131. At this time, since the first connection port 131 is in communication with the outside of the switching valve 13, the operation air that has flowed into the switching valve 13 is discharged to the outside.

[0047] As described above, by applying an electric signal to the first solenoid 134A or the second solenoid 134B to drive the valve body inside the switching valve 13, it is possible to switch between supplying the operating air to the first pressure application chamber 103 and supplying the operating air to the second pressure application chamber 104 (hereinafter, simply referred to as "air supply switching"). By repeating the switching of the air supply, the piston 102 can perform a reciprocating motion. The reciprocating motion of the piston 102 causes the reciprocating motion of the operating rod 105 connected to the piston 102. When the piston 102 moves to the second end 101b side, the operating rod 105 is driven to protrude from the double-acting cylinder 101, and conversely, when the piston 102 moves to the first end 101a side, the operating rod 105 is driven to retract into the double-acting cylinder 101. In addition, driving the operating rod 105 so that it protrudes from the double-acting cylinder 101 is called driving in the push direction, and conversely, driving the operating rod 105 so that it is retracted into the double-acting cylinder 101 is called driving in the pull direction.

[0048] The speed of the reciprocating motion of the operating rod 105 is controlled by adjusting the flow rate of the operating air by the flow rate adjusting units 14A and 14B, as will be described in more detail below.

[0049] For example, when controlling the operating speed of the operating rod 105 (meter-out control) by adjusting the flow rate of the operating air exhausted from the first pressure application chamber 103 or the second pressure application chamber 104, the check valves 141A, 141B of the flow rate adjustment units 14A, 14B are configured to allow the flow of operating air from the switching valve 13 side to the fluid pressure actuator 10 side, while preventing the operating air from flowing in the reverse direction.

[0050] When the operating rod 105 is driven in the push direction, the operating air is supplied from the first pipe 11 to the first pressure application chamber 103. In this case, the check valve 141A of the flow rate adjustment unit 14A on the first pipe 11 allows the flow of the operating air toward the first pressure application chamber 103, so that the operating air is supplied to the first pressure application chamber 103. Then, when the piston 102 is moved in the push direction, the operating air is exhausted from the second pressure application chamber 104 to the second pipe 12. At this time, the operating air cannot pass through the check valve 141B of the flow rate adjustment unit 14B on the second pipe 12, so it passes through the flow rate adjustment valve 142B. Therefore, the flow rate of the operating air is limited according to the valve opening degree of the flow rate adjustment valve 142B, and the moving speed of the piston 102 in the push direction is controlled (i.e., the moving speed of the operating rod 105 in the push direction is controlled).

[0051] Conversely, when the operating rod 105 is driven in the pull direction, the operating air is supplied from the second pipe 12 to the second pressure application chamber 104. In this case, the check valve 141B of the flow rate adjustment unit 14B on the second pipe 12 allows the operating air to flow toward the second pressure application chamber 104, so that the operating air is supplied to the second pressure application chamber 104. Then, when the piston 102 is moved in the pull direction, the operating air is exhausted from the first pressure application chamber 103 to the first pipe 11. At this time, the operating air cannot pass through the check valve 141A of the flow rate adjustment unit 14A on the first pipe 11, so it passes through the flow rate adjustment valve 142A. Therefore, the flow rate of the operating air is limited according to the valve opening of the flow rate adjustment valve 142A, and the moving speed of the piston 102 in the pull direction is controlled (i.e., the moving speed of the operating rod 105 in the pull direction is controlled).

[0052] On the other hand, for example, when controlling the operating speed of the operating rod 105 (meter-in control) by adjusting the flow rate of the operating air supplied to the first pressure application chamber 103 or the second pressure application chamber 104, the check valves 141A, 141B of the flow rate adjustment units 14A, 14B are configured to allow the flow of operating air from the fluid pressure actuator 10 side to the switching valve 13 side, while preventing the operating air from flowing in the reverse direction.

[0053] When the operating rod 105 is driven in the push direction, compressed air is supplied from the first pipe 11 to the first pressure application chamber 103. In this case, the operating air cannot pass through the check valve 141A of the flow rate adjustment unit 14A on the first pipe 11, so it passes through the flow rate adjustment valve 142A and is supplied to the first pressure application chamber 103. Therefore, the flow rate of the operating air is limited according to the valve opening degree of the flow rate adjustment valve 142A, and the moving speed of the piston 102 in the push direction is controlled (i.e., the moving speed of the operating rod 105 in the push direction is controlled). Then, when the piston 102 is moved in the push direction, the operating air is exhausted from the second pressure application chamber 104 to the second pipe 12. At this time, the check valve 141B of the flow rate adjustment unit 14B on the second pipe 12 allows the flow of the operating air toward the switching valve 13.

[0054] Conversely, when the operating rod 105 is driven in the pull direction, the operating air is supplied from the second pipe 12 to the second pressure application chamber 104. In this case, the operating air cannot pass through the check valve 141B of the flow rate adjustment unit 14B on the second pipe 12, so it passes through the flow rate adjustment valve 142B and is supplied to the second pressure application chamber 104. Therefore, the flow rate of the operating air is limited according to the valve opening degree of the flow rate adjustment valve 142B, and the moving speed of the piston 102 in the pull direction is controlled (i.e., the moving speed of the operating rod 105 in the pull direction is controlled). Then, when the piston 102 is moved in the pull direction, the operating air is exhausted from the first pressure application chamber 103 to the first pipe 11. At this time, the check valve 141A of the flow rate adjustment unit 14A on the first pipe 11 allows the flow of the operating air toward the switching valve 13.

[0055] <About the condition monitoring system> Next, we will explain the condition monitoring system 1. As shown in Fig. 1, the main components of the condition monitoring system 1 are a controller 2, a first pressure sensor 3 (an example of a sensor), a second pressure sensor 4 (an example of a sensor), cylinder switches 6A and 6B (an example of a sensor), a temperature sensor 7 (an example of a sensor), and a condition monitoring device 5 (an example of a monitoring means).

[0056] The controller 2 switches the air supply by applying an electric signal to the first solenoid 134A or the second solenoid 134B, thereby controlling the operation of the fluid pressure actuator 10.

[0057] The first pressure sensor 3 is disposed on the first pipe 11 between the flow rate adjustment unit 14A and the fluid pressure actuator 10. As a result, the first pressure sensor 3 detects a pressure value (an example of a physical quantity) in the first pipe 11. This is synonymous with detecting a pressure value (first pressure value) of the first pressure application chamber 103. This is because, according to Pascal's principle, the pressure applied to the inner wall of the first pressure application chamber 103 and the inner wall of the first pipe 11 communicating with the first pressure application chamber 103 is uniform.

[0058] Moreover, the second pressure sensor 4 is disposed on the second pipe 12 between the flow rate adjustment unit 14B and the fluid pressure actuator 10. As a result, the second pressure sensor 4 detects a pressure value (an example of a physical quantity) in the second pipe 12. This is synonymous with detecting a pressure value (second pressure value) of the second pressure application chamber 104. This is because, according to Pascal's principle, the pressure applied to the inner wall of the second pressure application chamber 104 and the inner wall of the second pipe 12 communicating with the second pressure application chamber 104 is uniform.

[0059] The cylinder switches 6A and 6B are magnetic sensors that detect the approach of the piston 102 to the cylinder switches by sensing the magnetism of a magnet built into the piston 102. The cylinder switch 6A is provided on the first end 101a side of the double-acting cylinder 101. As a result, when the piston 102 is located on the first end 101a side, the cylinder switch 6A senses the piston 102 and generates an electric signal. The cylinder switch 6B is provided on the second end 101b side of the double-acting cylinder 101. As a result, when the piston 102 is located on the second end 101b side, the cylinder switch 6A senses the piston 102 and generates an electric signal. And, while neither the cylinder switch 6A nor the cylinder switch 6B is emitting an electric signal, it means that the piston 102 is moving.

[0060] The temperature sensor 7 is, for example, a sensor such as a resistance temperature detector, a thermistor, or a thermocouple, and is installed in the vicinity of the fluid pressure actuator 10. The temperature sensor 7 is used to sense the temperature (an example of a physical quantity, hereinafter simply referred to as the ambient temperature) around the fluid pressure actuator 10. The temperature sensor 7 may be built into the status monitoring device 5.

[0061] The status monitoring device 5 includes a calculation unit 51. Furthermore, the status monitoring device 5 includes a detection unit 52, an internal clock 53 (an example of a sensor), a display unit 56, a storage unit 57, and a communication unit 58, which are electrically connected to the calculation unit 51.

[0062] The calculation unit 51 monitors the operating status of the fluid pressure actuator 10 based on information input to the status monitoring device 5 from the control controller 2, pressure sensors 3, 4, cylinder switches 6A, 6B, and temperature sensor 7 in accordance with a status monitoring program (details will be described later).

[0063] The detection unit 52 is electrically connected to the first pressure sensor 3 and the second pressure sensor 4. The first pressure sensor 3 and the second pressure sensor 4 output the detected pressure values ​​as analog signals, so the detection unit 52 converts them into digital signals and transmits the data of the first pressure value and the data of the second pressure value to the calculation unit 51.

[0064] Furthermore, the detection unit 52 is electrically connected to the cylinder switches 6A, 6B, and the electric signals given to the controller 2 by the cylinder switches 6A, 6B are branched and input to the detection unit 52. This allows the status monitoring device 5 to know the time when the cylinder switches 6A, 6B issued the electric signals. Furthermore, the detection unit 52 is electrically connected to the temperature sensor 7, and the status monitoring device 5 can obtain information on the ambient temperature.

[0065] Furthermore, the detection unit 52 is electrically connected to the control controller 2, and the electrical signal given by the control controller 2 to the first solenoid 134A or the second solenoid 134B is branched and input to the detection unit 52. This allows the state monitoring device 5 to grasp the point in time when the electrical signal is given to the first solenoid 134A or the second solenoid 134B.

[0066] The internal clock 53 is used to measure time, and is capable of continuing to measure time using a built-in battery of the status monitoring device 5 even when the power to the status monitoring device 5 is turned off.

[0067] The display unit 56 is, for example, an LED or the like, and is capable of displaying the operating state of the fluid pressure actuator 10 according to the operating state of the piston 102 and the point in time when the air supply is switched at the switching valve 13. Furthermore, as will be described later, when the condition monitoring device 5 determines that the fluid pressure actuator 10 has deteriorated, it is also possible to display that effect.

[0068] The storage unit 57 stores the detection program, and is also capable of storing the results of calculations performed by the calculation unit 51. The communication unit 58 is capable of communicating between the state monitoring device 5 and a computer (PC6) connected to the state monitoring device 5, and can output the results of calculations performed by the calculation unit 51 to the PC6, for example.

[0069] <About the operation of the status monitoring program> The condition monitoring system 1 configured as described above converts the physical quantities input from the pressure sensors 3, 4, cylinder switches 6A, 6B, and temperature sensor 7 into performance values, which are data related to the performance of the fluid pressure actuator 10, and environmental values, which are data related to the usage conditions of the fluid pressure actuator 10, in accordance with the condition monitoring program, and monitors the condition of the fluid pressure actuator 10 based on the performance values ​​and environmental values.

[0070] The performance values ​​are data related to the performance of the fluid pressure actuator 10, such as the response time, the movement time of the piston 102, the thrust acting on the piston 102 (hereinafter simply referred to as thrust), and the air consumption of the operating air within the cylinder (hereinafter simply referred to as air consumption).

[0071] The response time is the time from when the air supply is switched to when the piston 102 starts to move. Specifically, the state monitoring device 5 measures, with the internal clock 53, the time from when an electric signal is given to the first solenoid 134A to when the cylinder switch 6A stops emitting an electric signal, or the time from when an electric signal is given to the second solenoid 134B to when the cylinder switch 6B stops emitting an electric signal, thereby obtaining the response time.

[0072] The movement time is the time taken for the piston 102 to move from the first end 101a side to the second end 101b side in the double-acting cylinder 101 (the time taken for movement in the push direction), or the time taken for the piston 102 to move from the second end 101b side to the first end 101a side in the double-acting cylinder 101 (the time taken for movement in the pull direction). Specifically, the state monitoring device 5 measures the time from when the cylinder switch 6A stops emitting an electric signal until the cylinder switch 6B emits an electric signal, or the time from when the cylinder switch 6B stops emitting an electric signal until the cylinder switch 6A emits an electric signal, using the internal clock 53, to obtain the movement time.

[0073] The thrust is a force that the operating air applies to the piston 102 in order to move the piston 102 in the push direction or the pull direction. Specifically, the state monitoring device 5 calculates the difference between a value obtained by multiplying the pressure-receiving area on the first end 101a side of the piston 102 by the pressure value of the first pressure application chamber 103 obtained by the first pressure sensor 3, and a value obtained by multiplying the pressure-receiving area on the second end 101b side of the piston 102 by the pressure value of the second pressure application chamber 104 obtained by the second pressure sensor 4. The pressure-receiving area is a value specific to the fluid pressure actuator 10, and is used in the above calculation by, for example, inputting the pressure-receiving area of ​​the piston 102 to the state monitoring device 5 in advance.

[0074] The air consumption is the amount of operating air leaking between the first pressure application chamber 103 and the second pressure application chamber 104. Specifically, it is obtained by calculating and comparing the air consumption of the pneumatic device under normal conditions and the air consumption after deterioration from the air flow rate measured by the flow sensor.

[0075] The environmental values ​​are data relating to the usage conditions of the fluid pressure actuator 10, such as the ambient temperature, the pressure of the operating air supplied to the fluid pressure actuator 10 (hereinafter simply referred to as the supply pressure), the time the fluid pressure actuator 10 is stopped (hereinafter simply referred to as the stop time), and the operating period of the fluid pressure actuator 10 (hereinafter simply referred to as the operating period).

[0076] As already described, the ambient temperature is the temperature around the fluid pressure actuator 10, obtained by the temperature sensor 7. The supply pressure is the pressure of the operating air supplied to the first pressure application chamber 103 or the second pressure application chamber 104, and is obtained by the first pressure sensor 3 or the second pressure sensor 4.

[0077] The stop time is the time that the piston 102 is stopped at the first end 101a side or the second end 101b side in the double-acting cylinder 101. Specifically, the state monitoring device 5 obtains the time that the cylinder switch 6A or the cylinder switch 6B is emitting an electric signal by using the internal clock 53.

[0078] The operating cycle is the operating frequency of the fluid pressure actuator 10, and is the time from when the piston 102 starts reciprocating until the next reciprocating motion starts. Specifically, the status monitoring device 5 measures the time between the reciprocating motion of the piston 102 detected by the cylinder switch 6A and the cylinder switch 6B and the next reciprocating motion using the internal clock 53.

[0079] First, the status monitoring device 5 acquires the above-mentioned performance values ​​and environmental values ​​each time the fluid pressure actuator 10 performs one operation, and generates time series data of the performance values ​​and environmental values. Here, FIG. 2 is a table showing an example of the time series data of the performance values ​​and environmental values. Also, FIG. 3(a) is a graph of the time series data of the movement time, which is included in the time series data of the performance values ​​shown in FIG. 2. FIG. 3(b) is a graph of the corrected value of the time series data of the movement time.

[0080] The "count value" in FIG. 2 includes information on the "date", "hours, minutes, and seconds", and "number of operations". The "date" is the date on which the fluid pressure actuator 10 was operated, and the description "230825" in the table means August 25, 2023. Next, the "hours, minutes, and seconds" is the time on the date indicated by the "date" when the fluid pressure actuator 10 was operated (more specifically, the time when an electrical signal was given from the control controller 2 to the switching valve 13 to operate the fluid pressure actuator 10). For example, "151200" in the table means 15:12:00. The "number of operations" is the cumulative number of operations of the fluid pressure actuator 10 on the date indicated by the "date". For example, "2671" in the table means the 2671st operation, and "2672" means the 2672nd operation. The "date", "hours, minutes, and seconds", and "number of operations" are all information acquired by the internal clock 53.

[0081] In summary, this means that the 2671st operation (reciprocating motion of the piston 102) of the fluid pressure actuator 10 was performed at 15:12:00 on Aug. 25, 2023. The number of operations is counted each time the piston 102 moves in the push direction or pull direction, and in this embodiment, each operation in the push direction is counted as one.

[0082] The performance values ​​and environmental values ​​when the fluid pressure actuator 10 performed the 2671st operation are recorded in the same row in the table of FIG. 2. That is, the movement time in the first operation (the time required for movement in the pull direction or push direction, in this embodiment, the time required for movement in the push direction) is 0.72 seconds. As for the thrust, the maximum thrust and the average thrust are recorded. That is, the maximum thrust during the 2671st operation is 50.5 N, and the average thrust during the 2671st operation is 45.2 N. The operation cycle in the 2671st operation is 11 seconds. Also, the stop time in the 2671st operation is 6 seconds. This means that the fluid pressure actuator 10 stopped operating for 6 seconds before starting the 2671st operation. Furthermore, the supply pressure in the 2671st operation is 0.61 MPa, and the ambient temperature in the 2671st operation is 30.5°C. The table of FIG. 2 similarly shows the 2672nd and subsequent operations of the fluid pressure actuator 10.

[0083] The status monitoring device 5 (calculation unit 51) generates the above-mentioned time series data, for example, on a daily basis, and stores it in the storage unit 57. Note that the table shown in Fig. 2 is an excerpt of data for operation counts 2671-2688 from the time series data for one day, and data from operation count 2689 onwards is omitted. Also, generating the time series data on a daily basis is merely an example, and the data may be generated, for example, on a several-hour basis.

[0084] Since the performance value is considered to increase or decrease due to the deterioration of the fluid pressure actuator 10, when the performance value reaches a predetermined threshold, the state monitor 5 (calculation unit 51) determines that the fluid pressure actuator 10 has deteriorated. Specifically, for example, when the packing provided on the outer periphery of the piston 102 deteriorates, the slidability of the piston 102 may decrease and the air consumption of the operating air may increase. This may result in a longer response time and movement time. In addition, when the grease for ensuring the slidability of the piston 102 is depleted, the response time and movement time may increase and the thrust required to move the piston 102 may increase due to the decrease in the slidability of the piston 102. For this reason, when the performance value (response time, movement time, thrust, air consumption) reaches a threshold, it is determined that some part of the fluid pressure actuator 10 has deteriorated, and replacement with a new fluid pressure actuator 10 is recommended. The above threshold value may be a value determined according to the performance value required for the fluid pressure actuator 10, or may be a value at which it is possible to empirically determine that deterioration has progressed.

[0085] However, since the performance values ​​of the fluid pressure actuator 10 may be affected by environmental values, simply monitoring the performance values ​​may not be enough to accurately determine whether or not the fluid pressure actuator 10 has deteriorated.

[0086] Specifically, the viscosity of the grease depends on the ambient temperature. When the viscosity of the grease changes, the sliding resistance also changes, which may increase the response time, movement time, and thrust. In addition, if the stop time is long, the packing pushes aside the grease, causing it to adhere to the inner surface of the double-acting cylinder 101, which may increase the response time, movement time, and thrust. In this way, even if there is no actual deterioration, there is a risk that the performance values ​​(response time, movement time, thrust, and air consumption) may exceed the threshold value.

[0087] For example, Fig. 3(a) is a graph of the time series data of the movement time among the time series data of the performance values ​​shown in the table of Fig. 2, in which the operation time increases as the number of operations increases, and reaches the threshold value T11 near time t11. However, in Fig. 3(a), since the operation time decreases after time t11 has passed, it is possible to consider that the reaching of the threshold value T11 near time t11 is due to the influence of the environmental value. For this reason, if it is determined that the fluid pressure actuator 10 has deteriorated simply when the performance value reaches the threshold value T11, this may lead to an erroneous determination.

[0088] Therefore, the state monitoring device 5 (calculation unit 51) calculates the correlation coefficient between the time series data of the performance value and the time series data of the environmental value by using the formula (1). Here, n in the formula (1) represents the total number of two-variable data (x, y), and x i andy i represents the numerical value of each data item, TIFF2025063749000002.tif7165Each represents the average value of the variables.

[0089]

number

[0090] Specifically, at least one time series data is selected from among the performance values ​​of response time, travel time, thrust, and air consumption, and for each selected performance value, a correlation coefficient is calculated with at least one time series data of the environmental values ​​of ambient temperature, supply pressure, stop time, and operating cycle.

[0091] Here, as an example, travel time is selected from among the performance values, and correlation coefficients between the ambient temperature, supply pressure, and stop time, which are among the environmental values, are calculated. More specifically, the correlation coefficient between the time series data of travel time and the time series data of ambient temperature, the correlation coefficient between the time series data of travel time and the time series data of supply pressure, and the correlation coefficient between the time series data of travel time and the time series data of stop time are calculated. Here, FIG. 4(a) is a graph showing the correlation between the time series data of travel time and the time series data of ambient temperature. FIG. 4(b) is a graph showing the correlation between the time series data of travel time and the time series data of supply pressure. FIG. 4(c) is a graph showing the correlation between the time series data of travel time and the time series data of stop time.

[0092] The graph in Figure 4(a) shows a negative correlation, where the travel time decreases as the ambient temperature increases. The correlation coefficient is -0.85, which indicates a strong correlation between the travel time and the ambient temperature.

[0093] According to the graph shown in Figure 4(b), there is no relationship between the travel time and the supply pressure, such that if one value increases, the other value increases or decreases. The correlation coefficient is 0.03, and the correlation between the travel time and the supply pressure is considered to be weak.

[0094] The graph in Figure 4(c) shows that there is no relationship between movement time and stop time, such that if one value increases, the other value increases or decreases. The correlation coefficient is 0.10, and the correlation between movement time and stop time is considered to be weak.

[0095] As described above, by calculating the correlation coefficient, it is possible to see the strength of the correlation between the performance value and the environmental value, and therefore to grasp the strength of the influence of the environmental value on the performance value. If the influence is strong, it is clear that the performance value is influenced by the environmental value, and therefore when an abnormality occurs in the performance value (in the above example, the moving speed), it is possible to identify the cause if it is due to the influence of the environmental value (in the above example, the ambient temperature).

[0096] Next, the state monitoring device 5 (calculation unit 51) calculates a regression equation based on the time series data of the performance values ​​and the time series data of the environmental values, and corrects the time series data of the performance values ​​using the regression equation. This correction means obtaining a value (corrected value) obtained by removing the influence of the environmental values ​​from the time series data of the performance values.

[0097] Specifically, a correction is performed to remove the influence of environmental values ​​that have a strong influence on at least one of the performance values ​​such as travel time, thrust, and air consumption. Here, it is determined that the influence is strong when the absolute value of the correlation coefficient is 0.3 or more. In the above example, since the absolute value of the correlation coefficient between the time series data of travel time and the time series data of ambient temperature is 0.3 or more, a regression equation is calculated based on the time series data of travel time and the time series data of ambient temperature, and the time series data of travel time is corrected using the regression equation.

[0098] For example, (x i ,y i ) (i=1,2,...n), assuming that it satisfies equation (2), the regression equation can be obtained as equation (4) using equation (3). The regression line R11 expressed by this regression equation is shown in Figure 4(a). Here, β0 represents the intercept and β1 represents the slope.

[0099]

number

[0100]

number

[0101]

number

[0102] In this case, the estimated value under the reference condition x0 is expressed by the formula (5).

[0103]

number

[0104] The estimated value under condition x is expressed by equation (6).

[0105]

number

[0106] The correction value for the measured value y (i.e., the value excluding the influence of the environmental value) is expressed by equation (7) or equation (8).

[0107]

number

[0108]

number

[0109] In the above manner, the effect of the ambient temperature has been removed from the time series data of the movement time, as shown in the graph in FIG. 3(b). The time series data of the movement time after correction (corrected value) shown in FIG. 3(b) shows a suppressed increase in the movement time over time compared to the time series data of the movement time (measured value) shown in FIG. 3(a), and the threshold value T11 is not reached even near time point t11. This shows that the measured value reaches the threshold value T11 due to the effect of the environmental value, and not due to deterioration of the fluid pressure actuator 10. In other words, by monitoring the corrected value of the performance value, it is possible to grasp the accurate performance of the fluid pressure actuator 10 excluding the effect of the environmental value, and there is no erroneous judgment that the fluid pressure actuator 10 has deteriorated.

[0110] The correction value is stored in the storage unit 57. Therefore, for example, by comparing a correction value stored in the past (for example, a correction value immediately after starting to use the fluid pressure actuator 10) with the latest correction value, it is possible to grasp the degree of deterioration of the fluid pressure actuator 10.

[0111] In the above example, correction is performed on the multiple selected environmental values ​​whose absolute correlation coefficient is 0.3 or more. However, it is also possible to correct the environmental value with the largest correlation coefficient among the multiple selected environmental values.

[0112] Furthermore, in the above example, correction is performed on one environmental value (ambient temperature) among multiple selected environmental values ​​(ambient temperature, supply pressure, stop time), but multiple environmental values ​​may be corrected simultaneously by multiple regression.

[0113] As an example, a case where thrust force correction is performed will be described. Fig. 5(a) is a graph of the time series data of maximum thrust force among the time series data of performance values ​​shown in the table of Fig. 2. Fig. 5(b) is a graph of the value obtained by correcting the time series data of travel time using one environmental value. Fig. 5(c) is a graph of the corrected value obtained by multiple regression of the time series data of travel time.

[0114] 5(a), values ​​exceeding the threshold value T12 occur frequently, and it is unclear whether this is due to deterioration of the fluid pressure actuator 10. Therefore, the state monitoring device 5 (calculation unit 51) calculates a correlation coefficient between the time series data of the maximum thrust and the time series data of the environmental value.

[0115] Specifically, for example, the ambient temperature, supply pressure, and downtime are selected from the environmental values, and the correlation coefficient between each of the time series data and the time series data of the maximum thrust is calculated. Here, Fig. 6(a) is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the ambient temperature. Fig. 6(b) is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the supply pressure. Fig. 6(c) is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the downtime.

[0116] The graph in Figure 6(a) shows that there is a negative correlation, that is, the thrust decreases as the ambient temperature increases. The correlation coefficient is -0.88, which indicates that there is a strong correlation between thrust and ambient temperature.

[0117] According to the graph shown in Figure 6(b), there is no relationship between thrust and supply pressure such that if one value increases, the other value increases or decreases. The correlation coefficient is 0.04, and the correlation between thrust and supply pressure is considered to be weak.

[0118] The graph in Figure 6(c) shows that there is a positive correlation between the thrust and the stopping time. The correlation coefficient is -0.40, which indicates that there is a strong correlation between the thrust and the stopping time.

[0119] For thrust, the absolute value of the correlation coefficient with the ambient temperature and the correlation coefficient with the stop time is 0.3 or more. Therefore, the state monitoring device 5 (calculation unit 51) performs multiple regression based on the time series data of thrust and the time series data of the ambient temperature and the stop time, and corrects the time series data of thrust. In other words, a value obtained by removing the influence of the ambient temperature and the stop time from the time series data of thrust is obtained. A regression line R12 represented by a regression equation calculated based on the time series data of maximum thrust and the time series data of the ambient temperature is shown in FIG. 6(a), and a regression line R13 represented by a regression equation calculated based on the time series data of maximum thrust and the time series data of the stop time is shown in FIG. 6(c).

[0120] The graph in Fig. 5(b) shows the maximum thrust time series data after excluding the influence of only the ambient temperature. The corrected travel time time series data (corrected value) shown in Fig. 5(b) has less data variance than the travel time time series data (measured value) shown in Fig. 5(a), but there is a lot of data that exceeds the threshold value T12. This is because the influence of the stop time, which has a large correlation coefficient, remains, and the performance of the fluid pressure actuator 10 cannot be accurately grasped.

[0121] The graph shown in Fig. 5(c) further excludes the effects of the downtime. The data variation is further reduced compared to the corrected values ​​shown in Fig. 5(b), and there is no data exceeding the threshold value T12. It is therefore clear that the measured value reaches the threshold value T12 due to the effects of the environmental values ​​(ambient temperature and downtime), and not due to deterioration of the fluid pressure actuator 10. In this way, by monitoring the corrected values ​​using multiple regression, it is possible to grasp the accurate performance of the fluid pressure actuator 10 excluding the effects of the environmental values, and there is no erroneous determination that the fluid pressure actuator 10 has deteriorated.

[0122] As described above, according to the state monitoring system 1 of this embodiment, (1) A condition monitoring system 1 that monitors the operating state of a pneumatic device (e.g., a fluid pressure actuator 10) that operates using operating air as a driving source is characterized by comprising sensors (e.g., a first pressure sensor 3, a second pressure sensor 4, cylinder switches 6A, 6B, a temperature sensor 7, an internal clock 53) for acquiring physical quantities reflecting the operating state and usage environment of the pneumatic device (fluid pressure actuator 10), and a monitoring means (e.g., a condition monitoring device 5) having a condition monitoring program for converting the physical quantities (e.g., pressure value, ambient temperature, time) acquired by the sensors into performance values ​​that are data related to the performance of the pneumatic device (fluid pressure actuator 10) and environmental values ​​that are data related to the usage conditions of the pneumatic device (fluid pressure actuator 10), generating time series data of the performance values ​​and time series data of the environmental values, and calculating a correlation coefficient between the time series data of the performance values ​​and the time series data of the environmental values.

[0123] (2) In the condition monitoring system 1 described in (1), it is preferable that the pneumatic device (fluid pressure actuator 10) has a piston 102 that slides inside a cylinder (e.g., a double-acting cylinder 101) by operating air, that the performance values ​​include at least one of the response time of the pneumatic device (fluid pressure actuator 10), the movement time of the piston 102, the thrust force acting on the piston 102 by the operating air, and the air consumption of the operating air in the cylinder (double-acting cylinder 101), and that the environmental values ​​include at least one of the ambient temperature, which is the temperature around the pneumatic device (fluid pressure actuator 10), the supply pressure, which is the pressure of the operating air supplied to the pneumatic device (fluid pressure actuator 10), the stop time, which is the time during which the pneumatic device (fluid pressure actuator 10) is stopped, and the operating period of the pneumatic device (fluid pressure actuator 10).

[0124] According to the above-described condition monitoring system 1, it is possible to grasp the strength of the influence of the environmental value on the performance value by calculating a correlation coefficient between the time series data of the performance value of the pneumatic device (fluid pressure actuator 10) and the time series data of the environmental value of the pneumatic device (fluid pressure actuator 10). If the influence is strong, it is understood that the performance value is influenced by the environmental value, and therefore, when an abnormality occurs in the performance value, it is possible to identify the cause if it is due to the influence of the environmental value.

[0125] More specifically, if at least one of the environmental values ​​such as the ambient temperature, supply pressure, down time, and operating cycle (hereinafter, specific environmental value) has a strong influence on at least one of the performance values ​​such as the response time of the pneumatic device (fluid pressure actuator 10), the movement time of the piston 102, the thrust acting on the piston 102, and the air consumption of the operating air (hereinafter, specific performance value), then when an abnormality occurs in the specific performance value, it becomes possible to identify the cause if it is due to the influence of the specific environmental value (for example, if the ambient temperature has a strong influence on the movement time, then when an abnormality occurs in the movement time, it becomes possible to identify the cause if it is due to the influence of the ambient temperature). Thus, it becomes possible to appropriately monitor the state of the pneumatic device (fluid pressure actuator 10).

[0126] (3) In the condition monitoring system 1 described in (1) or (2), it is preferable that the condition monitoring program calculates a regression equation (regression lines R11, R12, R13) based on time series data of performance values ​​and time series data of environmental values, and corrects the performance values ​​using the regression equation (regression lines R11, R12, R13).

[0127] In the condition monitoring system 1 described in (4)(3), it is preferable that the condition monitoring program performs the correction on a combination of the environmental value and the performance value for which the absolute value of the correlation coefficient is 0.3 or more.

[0128] According to the above-mentioned condition monitoring system 1, the performance value is corrected by the regression equation (regression lines R11, R12, R13), so that the performance of the pneumatic device (fluid pressure actuator 10) can be accurately grasped without being affected by the environmental value. This allows the deterioration degree of the pneumatic device (fluid pressure actuator 10) to be accurately grasped. Therefore, it is possible to perform maintenance of the pneumatic device (fluid pressure actuator 10) at an appropriate timing, or to improve the pneumatic device by optimizing the use conditions of the pneumatic device. In addition, it is possible to prevent the device (robot arm, etc.) using the pneumatic device (fluid pressure actuator 10) from stopping unintentionally. In addition, it is possible to use the pneumatic device (fluid pressure actuator 10) for as long as possible until it deteriorates, thereby reducing the frequency of maintenance. Furthermore, it is possible to minimize the energy loss for driving the pneumatic device (fluid pressure actuator 10).

[0129] Here, it is desirable to correct the performance value for the environmental value that has a strong influence on the performance value. Specifically, when the absolute value of the correlation coefficient is 0.3 or more, it is determined that the influence is strong, and correction is performed. More specifically, when the correlation coefficient between a specific performance value and a specific environmental value is 0.3 or more, correction is performed to remove the influence of the specific environmental value from the specific performance value (for example, when the correlation coefficient between the travel time and the ambient temperature is 0.3 or more, correction is performed to remove the influence of the ambient temperature from the travel time). The reason why correction is performed when the absolute value of the correlation coefficient is 0.3 or more is that the inventors have confirmed through experiments that environmental values ​​with a correlation coefficient smaller than 0.3 have a small influence on the performance value.

[0130] In order to solve the above problems, the condition monitoring method of the present invention has the following configuration.

[0131] (5) A condition monitoring method for monitoring the operating state of a pneumatic device (fluid pressure actuator 10) that operates using operating air as a driving source, characterized in that a performance value, which is data related to the performance of the pneumatic device (fluid pressure actuator 10), and an environmental value, which is data related to the usage conditions of the pneumatic device (fluid pressure actuator 10), are acquired, time series data of the performance value and time series data of the environmental value are generated, and a correlation coefficient between the time series data of the performance value and the time series data of the environmental value is calculated.

[0132] (6) In the condition monitoring method described in (5), it is preferable that the pneumatic device (fluid pressure actuator 10) has a sliding part (e.g., piston 102) that is operated by operating air, the performance values ​​include at least one of the response time of the pneumatic device (fluid pressure actuator 10), the movement time of the sliding part (piston 102), the thrust force acting on the sliding part (piston 102) by the operating air, and the air consumption of the operating air in the pneumatic device (fluid pressure actuator 10), and the environmental values ​​include at least one of the ambient temperature, which is the temperature around the pneumatic device (fluid pressure actuator 10), the supply pressure, which is the pressure of the operating air supplied to the pneumatic device (fluid pressure actuator 10), the stop time, which is the time during which the pneumatic device (fluid pressure actuator 10) is stopped, and the operation cycle of the pneumatic device (fluid pressure actuator 10).

[0133] According to the above-described condition monitoring method, it is possible to grasp the strength of the influence of the environmental value on the performance value by calculating the correlation coefficient between the time series data of the performance value of the pneumatic device (fluid pressure actuator 10) and the time series data of the environmental value of the pneumatic device (fluid pressure actuator 10). If the influence is strong, it is understood that the performance value is influenced by the environmental value, and therefore, when an abnormality occurs in the performance value, it is possible to identify the cause if it is due to the influence of the environmental value.

[0134] More specifically, if at least one of the environmental values ​​such as the ambient temperature, supply pressure, down time, and operating cycle (hereinafter, specific environmental value) has a strong influence on at least one of the performance values ​​such as the response time of the pneumatic device (fluid pressure actuator 10), the movement time of the piston 102, the thrust acting on the piston 102, and the air consumption of the operating air (hereinafter, specific performance value), then when an abnormality occurs in the specific performance value, it becomes possible to identify the cause if it is due to the influence of the specific environmental value (for example, if the ambient temperature has a strong influence on the movement time, then when an abnormality occurs in the movement time, it becomes possible to identify the cause if it is due to the influence of the ambient temperature). Thus, it becomes possible to appropriately monitor the state of the pneumatic device (fluid pressure actuator 10).

[0135] In the condition monitoring method described in (7) (5) or (6), it is preferable to calculate a regression equation (regression lines R11, R12, R13) based on the time series data of the performance value and the time series data of the environmental value, and correct the performance value using the regression equation (regression lines R11, R12, R13).

[0136] In the condition monitoring method described in (8) and (7), it is preferable that the correction is performed when the absolute value of the correlation coefficient is 0.3 or more.

[0137] According to the above-mentioned condition monitoring method, the performance value is corrected by the regression equation (regression lines R11, R12, R13), so that the performance of the pneumatic device (fluid pressure actuator 10) can be accurately grasped without being affected by the environmental value. This allows the deterioration degree of the pneumatic device (fluid pressure actuator 10) to be accurately grasped. Therefore, it is possible to perform maintenance of the pneumatic device (fluid pressure actuator 10) at an appropriate timing. In addition, it is possible to prevent the device (robot arm, etc.) using the pneumatic device (fluid pressure actuator 10) from being stopped unintentionally. In addition, it is possible to use the pneumatic device (fluid pressure actuator 10) for as long as possible until it deteriorates, thereby reducing the frequency of maintenance. Furthermore, it is possible to minimize the energy loss for driving the pneumatic device (fluid pressure actuator 10).

[0138] Here, it is desirable to correct the performance value for the environmental value that has a strong influence on the performance value. Specifically, when the absolute value of the correlation coefficient is 0.3 or more, it is determined that the influence is strong, and correction is performed. More specifically, when the correlation coefficient between a specific performance value and a specific environmental value is 0.3 or more, correction is performed to remove the influence of the specific environmental value from the specific performance value (for example, when the correlation coefficient between the travel time and the ambient temperature is 0.3 or more, correction is performed to remove the influence of the ambient temperature from the travel time). The reason why correction is performed when the absolute value of the correlation coefficient is 0.3 or more is that the inventors have confirmed through experiments that environmental values ​​with a correlation coefficient smaller than 0.3 have a small influence on the performance value.

[0139] It should be noted that this embodiment is merely an example and does not limit the present invention in any way. Therefore, the present invention can be naturally improved and modified in various ways without departing from the scope of the present invention. For example, the state monitoring device 5 may be configured to monitor the operating state of a plurality of fluid pressure actuators 10. The state monitoring device 5 may also be configured to monitor the switching valve 13. The pressure sensors 3 and 4 have been described as being disposed on the first pipe 11 and the second pipe 12, but this is not limited thereto, and they may be built into the state monitoring device 5. In addition, the fluid pressure actuator 10 does not necessarily have to have the operating rod 105, and can be applied to an actuator having a double-acting cylinder such as a parallel hand. The state monitoring device 5 has been described as an example of a monitoring means, but the pressure sensors 3 and 4 may have the same function as the state monitoring device 5. [Explanation of symbols]

[0140] 1 Condition monitoring system 3. First pressure sensor (example of a sensor) 4. Second pressure sensor (example of sensor) 5. Status monitoring device (an example of a monitoring means) 6A Cylinder switch (example of a sensor) 6B Cylinder switch (example of a sensor) 7 Temperature sensor (example of sensor) 10 Fluid pressure actuator (an example of pneumatic equipment)

Claims

1. A condition monitoring system for monitoring the operating condition of pneumatic equipment that operates using operating air as a drive source, comprising: a sensor for acquiring a physical quantity reflecting an operating state and a usage environment of the pneumatic device; a monitoring means including a state monitoring program for converting the physical quantities acquired by the sensors into performance values, which are data related to the performance of the pneumatic device, and environmental values, which are data related to the usage conditions of the pneumatic device, generating time series data of the performance values ​​and time series data of the environmental values, and calculating a correlation coefficient between the time series data of the performance values ​​and the time series data of the environmental values; To have A condition monitoring system characterized by:

2. 2. The condition monitoring system according to claim 1, the pneumatic device has a sliding part that is operated by the operating air; The performance value includes at least one of a response time of the pneumatic device, a movement time of the sliding part, a thrust force acting on the sliding part by the operating air, and an air consumption of the operating air in the pneumatic device. The environmental value includes at least one of an ambient temperature, which is a temperature around the pneumatic device, a supply pressure, which is a pressure of the operating air supplied to the pneumatic device, a stop time, which is a time during which the pneumatic device is stopped, and an operation cycle of the pneumatic device. A condition monitoring system characterized by:

3. 3. The condition monitoring system according to claim 1, The state monitoring program Calculating a regression equation based on the time series data of the performance value and the time series data of the environmental value; correcting the performance value by the regression equation; A condition monitoring system characterized by:

4. 4. The condition monitoring system according to claim 3, The state monitoring program performing the correction on a combination of the environmental value and the performance value for which the absolute value of the correlation coefficient is 0.3 or more; A condition monitoring system characterized by:

5. A status monitoring method for monitoring an operating status of a pneumatic device that operates using operating air as a drive source, comprising: Acquiring a performance value, which is data related to the performance of the pneumatic device, and an environmental value, which is data related to the usage conditions of the pneumatic device; generating time series data of the performance values ​​and time series data of the environmental values; calculating a correlation coefficient between the time series data of the performance values ​​and the time series data of the environmental values; A condition monitoring method comprising:

6. 6. The condition monitoring method according to claim 5, the pneumatic device has a sliding part that is operated by the operating air; The performance value includes at least one of a response time of the pneumatic device, a movement time of the sliding part, a thrust force acting on the sliding part by the operating air, and an air consumption of the operating air in the pneumatic device. The environmental value includes at least one of an ambient temperature, which is a temperature around the pneumatic device, a supply pressure, which is a pressure of the operating air supplied to the pneumatic device, a stop time, which is a time during which the pneumatic device is stopped, and an operation cycle of the pneumatic device. A condition monitoring method comprising:

7. The condition monitoring method according to claim 5 or 6, Calculating a regression equation based on the time series data of the performance value and the time series data of the environmental value; correcting the performance value by the regression equation; A condition monitoring method comprising:

8. The condition monitoring method according to claim 7, performing the correction when the absolute value of the correlation coefficient is 0.3 or more; A condition monitoring method comprising:

Images