State monitoring system and state monitoring method

Abstract

The present invention provides a state monitoring system capable of properly monitoring the state of pneumatic equipment. The state monitoring system (1) of the present invention monitors the operating state of a pneumatic equipment that uses operating air as a driving source, and comprises: a sensor for acquiring physical quantities reflecting the operating state and use environment of the pneumatic equipment; and a state monitoring device (5) having a state monitoring program, wherein the state monitoring program is used to convert the physical quantities (such as pressure value, ambient temperature, time) acquired by the sensor into performance-related data of the pneumatic equipment, i.e., performance values, and data related to the use conditions of the pneumatic equipment, i.e., environment values, to generate time series data of the performance values ​​and time series data of the environment values, and calculate the correlation coefficient between the time series data of the performance values ​​and the time series data of the environment values.

Description

Technical Field

[0001] The present invention relates to a state monitoring system and a state monitoring method for monitoring the operation state of a pneumatic device that uses air pressure as a driving source to operate. Background Art

[0002] Conventionally, as pneumatic equipment that uses air pressure as a driving source to operate, fluid pressure actuators such as robot arms used in food factories, etc. are known. As fluid pressure actuators, for example, double-acting cylinders having a piston as a sliding portion, switching valves having a valve core as a sliding portion, etc. are known. For example, the interior of the double-acting cylinder is divided into a first pressure chamber and a second pressure chamber by a piston, and one end of a pipe for intake or exhaust of operating air is connected to each of the first pressure chamber and the second pressure chamber. The supply source of operating air is connected to the other end of the pipe via a switching valve, and the intake of air to the first pressure chamber and the intake of air to the second pressure chamber are switched by the switching valve, thereby causing the piston to reciprocate in the cylinder.

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

[0004] For example, by monitoring performance values ​​of the fluid pressure actuator such as response time, piston movement time, thrust acting on the piston, and air consumption of operating air in the cylinder, the degradation state of the fluid pressure actuator can be monitored.

[0005] For example, by using a sensor such as a cylinder switch to sense the time when the piston starts and stops moving, the piston's movement time can be calculated. If the fluid pressure actuator deteriorates (for example, the seal ring installed on the outer periphery of the piston deteriorates), the movement time will become longer. In other words, if Figure 7 As shown in the waveform formed by the solid line, as the number of times the fluid pressure actuator operates increases, the moving time increases. Therefore, a predetermined threshold value T21 is set, and at the time point (time point t21) when the moving time exceeds the threshold value T21, the fluid pressure actuator is judged to have deteriorated, and the fluid pressure actuator is repaired or the parts are replaced, or 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). Furthermore, the threshold value T21 can be a value determined according to the moving time required for the fluid pressure actuator, or a value that can be used to judge that the degradation has deepened based on experience.

[0006] As described above, by monitoring the performance value of the fluid pressure actuator, the fluid pressure actuator can be maintained at an appropriate time. By performing maintenance at an appropriate time, it is possible to prevent the fluid pressure actuator from abnormalities, thereby preventing the device (robot arm, etc.) using the fluid pressure actuator from stopping unexpectedly. In addition, the fluid pressure actuator can be used as long as possible before deterioration, reducing the frequency of maintenance. Furthermore, the increase in air consumption caused by air leakage due to deterioration such as wear of the seal ring of the sliding part is eliminated, thereby minimizing the energy loss used to drive the fluid pressure actuator. [Prior art literature] [Patent Document]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2018-59549 Summary of the invention [Problems to be solved by the invention]

[0008] However, we know that the performance value of pneumatic equipment (fluid pressure actuator) is sometimes affected by the use conditions, so it is not possible to accurately determine the timing of maintenance by simply monitoring the performance value. The details are explained below. Furthermore, the so-called use conditions include, for example, the ambient temperature of the fluid pressure actuator (hereinafter referred to as the ambient temperature), the pressure of the operating air supplied to the fluid pressure actuator (hereinafter referred to as the supply pressure), the time to stop the fluid pressure actuator (hereinafter referred to as the stop time), the action cycle of the fluid pressure actuator, etc.

[0009] For example, when lubricating oil is used on the sliding part of a fluid pressure actuator to improve sliding properties, the viscosity of the lubricating oil is affected by the ambient temperature. When the viscosity of the lubricating oil changes, the sliding resistance changes, so there is a possibility that the movement time of the sliding part will be prolonged (the movement speed will be slowed down). In addition, when the ambient temperature is low, the flexibility of the sliding part of the pneumatic device may be reduced and become hard. As a result, there is a possibility that the sealing of the sliding part becomes insufficient, the air leakage from the pneumatic device increases, and the movement time of the sliding part becomes prolonged (the movement speed becomes slowed down). Therefore, if Figure 7As shown in the waveform formed by the dotted line, there is a situation where the movement time exceeds the threshold value T21 at a time point (time point t22) when the degradation has not actually worsened. However, the user of the fluid pressure actuator does not know whether the reason for exceeding the threshold value T21 is due to the usage conditions or the degradation of the fluid pressure actuator, so it is possible that maintenance cannot be performed at the appropriate time, such as when maintenance is performed before the degradation has actually worsened. In addition, it is unclear which change in usage conditions caused the threshold value T21 to be exceeded, so it is impossible to improve it by rationalizing the usage conditions of the pneumatic equipment. Therefore, despite maintenance, the same abnormality may occur again. In addition, the types of pneumatic equipment actually connected and the usage conditions of the pneumatic equipment are diverse, so it is difficult to know which usage conditions affect the performance value and to what extent before the equipment starts to be used.

[0010] The present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a state monitoring system and a state monitoring method capable of appropriately monitoring the state of pneumatic equipment. [Technical means to solve the problem]

[0011] In order to solve the above-mentioned problems, the state monitoring system and the state monitoring method of the present invention have the following configurations.

[0012] (1) A state monitoring system for monitoring the operating state of a pneumatic device that uses operating air as a driving source, characterized in that it comprises: a sensor for acquiring physical quantities reflecting the operating state and usage environment of the pneumatic device; and a monitoring unit having a state monitoring program, wherein the state monitoring program is used to convert the physical quantities acquired by the sensor into data related to the performance of the pneumatic device, i.e., performance values, and data related to the usage conditions of the pneumatic device, i.e., environment values, generate time series data of the performance values ​​and time series data of the environment values, and calculate a correlation coefficient between the time series data of the performance values ​​and the time series data of the environment values.

[0013] (2) In the status monitoring system described in (1), the pneumatic device preferably has a sliding part that moves with the aid of the operating air, and the performance value includes at least any one of a response time of the pneumatic device, a movement time of the sliding part, a thrust applied to the sliding part by the operating air, and an air consumption of the operating air in the pneumatic device; and the environmental value includes at least any one of a temperature around the pneumatic device, i.e., the ambient temperature, a pressure of the operating air supplied to the pneumatic device, i.e., the supply pressure, a time for stopping the pneumatic device, i.e., the stop time, and an operation cycle of the pneumatic device.

[0014] According to the above-mentioned state monitoring system, by calculating the correlation coefficient between the time series data of the performance value of the pneumatic device (for example, a fluid pressure actuator having a sliding part (for example, a piston) that is moved by operating air) and the time series data of the environmental value of the pneumatic device, it is possible to understand whether the environmental value has an influence on the performance value. If the correlation is strong, it is known that the performance value is affected by the environmental value, so when an abnormality occurs in the performance value, it can be inferred that the cause is the influence of a specific environmental value.

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

[0016] (3) In the status monitoring system described in (1) or (2), the status monitoring program preferably 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 with the help of the regression equation.

[0017] According to the above-mentioned state monitoring system, the actual variation of the performance value can be obtained by correcting the performance value, thereby accurately understanding the performance of the pneumatic device without the influence of the environmental value, and thus appropriately monitoring the state 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-mentioned state monitoring system, since the performance value is corrected by means of a regression equation, the performance of the accurate pneumatic equipment without the influence of the environmental value can be grasped. As a result, the deterioration state of the pneumatic equipment can be accurately grasped. Therefore, the pneumatic equipment can be maintained at an appropriate time or improved by rationalizing the use conditions of the pneumatic equipment. Furthermore, it is possible to prevent the device (robot arm, etc.) using the pneumatic equipment from stopping unexpectedly. In addition, the pneumatic equipment can be used as long as possible before deterioration, reducing the frequency of maintenance. Furthermore, the energy loss used to drive the pneumatic equipment can be suppressed to a minimum.

[0020] Here, it is ideal to correct the performance value for the environmental value that has a strong correlation with the performance value. Specifically, when the absolute value of the correlation coefficient is greater than 0.3, it is judged 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 greater than 0.3, correction is performed to exclude the influence of the specific environmental value from the specific performance value (for example, when the absolute value of the correlation coefficient between the moving time and the ambient temperature is greater than 0.3, correction is performed to exclude the influence of the ambient temperature from the moving time). The reason why correction is performed when the absolute value of the correlation coefficient is greater than 0.3 is because the inventors have confirmed through experiments that the correlation between the environmental value with an absolute value of the correlation coefficient less than 0.3 and the performance value is weak.

[0021] Furthermore, in order to solve the above-mentioned problems, the state monitoring method of the present invention has the following configuration.

[0022] (5) A state monitoring method for monitoring the operating state of a pneumatic device that uses operating air as a driving source for operation, characterized in that data related to the performance of the pneumatic device, i.e., performance values, and data related to the use conditions of the pneumatic device, i.e., environmental values, are obtained, time series data of the performance values ​​and time series data of the environmental values ​​are generated, and a correlation coefficient between the time series data of the performance values ​​and the time series data of the environmental values ​​is calculated.

[0023] (6) In the state monitoring method described in (5), the pneumatic device preferably has a sliding part that moves with the aid of the operating air, and the performance value includes at least any one of a response time of the pneumatic device, a movement time of the sliding part, a thrust applied to the sliding part by the operating air, and an air consumption of the operating air in the pneumatic device; and the environmental value includes at least any one of a temperature around the pneumatic device, i.e., the ambient temperature, a pressure of the operating air supplied to the pneumatic device, i.e., the supply pressure, a time for stopping the pneumatic device, i.e., the stop time, and an action cycle of the pneumatic device.

[0024] According to the above-mentioned state monitoring method, by calculating the correlation coefficient between the time series data of the performance value of the pneumatic device (for example, a fluid pressure actuator having a sliding part (for example, a piston) that is moved by operating air) and the time series data of the environmental value of the pneumatic device, it is possible to understand whether the environmental value has an influence on the performance value. If the correlation is strong, it is known that the performance value is affected by the environmental value, so when an abnormality occurs in the performance value, it can be inferred that the cause is the influence of a specific environmental value.

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

[0026] (7) In the state monitoring method described in (5) or (6), it is preferred that a regression equation is calculated based on the time series data of the performance value and the time series data of the environmental value, and the performance value is corrected using the regression equation.

[0027] According to the above-mentioned state monitoring system, the actual variation of the performance value can be obtained by correcting the performance value, thereby accurately understanding the performance of the pneumatic device without the influence of the environmental value, and thus appropriately monitoring the state of the pneumatic device.

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

[0029] According to the above-mentioned state monitoring method, since the performance value is corrected by means of a regression equation, the performance of the accurate pneumatic equipment without the influence of the environmental value can be grasped. As a result, the degradation state of the pneumatic equipment can be accurately grasped. Therefore, the pneumatic equipment can be maintained at an appropriate time or improved by rationalizing the use conditions of the pneumatic equipment. Furthermore, it is possible to prevent the device (robot arm, etc.) using the pneumatic equipment from stopping unexpectedly. In addition, the pneumatic equipment can be used as long as possible before deterioration, reducing the frequency of maintenance. Furthermore, the energy loss used to drive the pneumatic equipment can be suppressed to a minimum.

[0030] Here, it is ideal to correct the performance value for the environmental value that has a strong correlation with the performance value. Specifically, when the absolute value of the correlation coefficient is greater than 0.3, it is judged 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 greater than 0.3, correction is performed to exclude the influence of the specific environmental value from the specific performance value (for example, when the absolute value of the correlation coefficient between the moving time and the ambient temperature is greater than 0.3, correction is performed to exclude the influence of the ambient temperature from the moving time). The reason why correction is performed when the absolute value of the correlation coefficient is greater than 0.3 is because the inventors have confirmed through experiments that the correlation between the environmental value with an absolute value of the correlation coefficient less than 0.3 and the performance value is weak. [Effects of the Invention]

[0031] According to the state monitoring system and the state monitoring method of the present invention, it is possible to appropriately perform state monitoring of pneumatic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a diagram showing a schematic configuration of a state monitoring system according to the present embodiment. Figure 2 This is a table showing an example of time series data of performance values ​​and environmental values. Figure 3A for Figure 2 The time series data of the movement time in the time series data of the performance value shown is graphed. Figure 3B This is a graph of the corrected values ​​of the time series data of the shift time. Figure 4A This is a graph showing the correlation between the time series data of the moving time and the time series data of the ambient temperature. Figure 4B This is a graph showing the correlation between the time series data of the travel time and the time series data of the supply pressure. Figure 4C This is a graph showing the correlation between the time series data of the moving time and the time series data of the stopping time. Figure 5A for Figure 2 The time series data of the maximum thrust is graphed among the time series data of the performance values ​​shown. Figure 5B This is a graph of the values ​​obtained by correcting the time series data of the maximum thrust using one environmental value. Figure 5C This is a graph of the correction values ​​from the multivariate regression of the time series data of maximum thrust. Fig. 6A This is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the ambient temperature. Figure 6B This is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the supply pressure. Figure 6C This is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the stop time. Figure 7 This is a graph showing the relationship between the performance value (movement time) of the fluid pressure actuator and the number of operations. DETAILED DESCRIPTION

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

[0034] 〈About Fluid Pressure Actuators〉 First, the structure of the fluid pressure actuator 10 is described. Figure 1 As shown, 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.

[0035] The piston 102 is slidably held inside the double-acting cylinder 101. The sliding direction of the piston 102 is, for example, along the long side direction of the double-acting cylinder 101. Figure 1 In the left and right direction. In addition, the piston 102 divides the interior of the double-acting cylinder 101 into a first pressure chamber 103 and a second pressure chamber 104. In addition, an operating rod 105 is connected to the end surface of the piston 102 on the second pressure chamber 104 side. The operating rod 105 passes through the end (second end 101b) on the second pressure chamber 104 side of the two ends in the long side direction of the double-acting cylinder 101 and extends to the outside of the double-acting cylinder 101.

[0036] One end of the first pipe 11 for taking in or out the operating air is connected to the end (first end 101a) on the first pressure action chamber 103 side of the two ends in the long-side direction of the double-acting cylinder 101. The first pipe 11 connected to the first end 101a is connected to the first pressure action chamber 103 through the internal flow path of the double-acting cylinder 101. In addition, the other end of the first pipe 11 is connected to the first connection port 131 of the switching valve 13.

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

[0038] The first pipe 11 is provided with a flow rate regulating portion 14A including a check valve 141A and a flow rate regulating valve 142A. The second pipe 12 is provided with a flow rate regulating portion 14B including a check valve 141B and a flow rate regulating valve 142B.

[0039] The switching valve 13 has an input port 133 for inputting the operating air into the switching valve 13. One end of the air intake duct 15 is connected to the input port 133, and the other end of the air intake duct 15 is connected to the supply source 16 of the operating 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 a controller 2 described later. Therefore, the controller 2 can apply an electrical signal to the first solenoid 134A or the second solenoid 134B to drive a valve core (not shown) inside the switching valve 13. A more specific description is given below.

[0041] When an electric signal is applied to the first solenoid 134A, the valve element (not shown) of the switching valve 13 is pulled toward the first solenoid 134A. As a result, the input port 133 communicates with the first connection port 131 , and the second connection port 132 communicates with the outside of the switching valve 13 .

[0042] The input port 133 is connected to the first connection port 131, and the operating air input from the supply source 16 to the switching valve 13 is output from the first connection port 131 to the first duct 11. The operating air output to the first duct 11 flows in the first duct 11 and is delivered to the first pressure chamber 103 of the double-acting cylinder 101.

[0043] When the operating air is taken into the first pressure chamber 103, the pressure inside the first pressure chamber 103 rises, and the piston 102 is pushed. As a result, the piston 102 moves toward the second end 101b side. While the piston 102 moves toward the second end 101b side (forward direction), the operating air previously supplied to the second pressure chamber 104 is discharged from the second pressure chamber 104. The operating air discharged from the second pressure chamber 104 flows into the switching valve 13 via the second pipe 12 and the second connection port 132. At this time, since the second connection port 132 is connected to the outside of the switching valve 13, the operating air flowing into the switching valve 13 is discharged to the outside (for example, discharged to the atmosphere).

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

[0045] The input port 133 is connected to the second connection port 132, and the operating air input from the supply source 16 to the switching valve 13 is output from the second connection port 132 to the second duct 12. The operating air output to the second duct 12 flows in the second duct 12 and is delivered to the second pressure chamber 104 of the double-acting cylinder 101.

[0046] When the operating air is supplied to the second pressure chamber 104, the pressure inside the second pressure chamber 104 rises, and the piston 102 is pushed. As a result, the piston 102 moves toward the first end 101a side (pull-back direction). While the piston 102 moves toward the first end 101a side, the operating air previously supplied to the first pressure chamber 103 is discharged from the first pressure chamber 103. The operating air discharged from the first pressure chamber 103 flows into the switching valve 13 via the first pipe 11 and the first connection port 131. At this time, since the first connection port 131 is connected to the outside of the switching valve 13, the operating air flowing into the switching valve 13 is discharged to the outside (for example, discharged to the atmosphere).

[0047] As described above, by applying an electric signal to the first solenoid 134A or the second solenoid 134B to drive the valve core inside the switching valve 13, the intake of the operating air to the first pressure action chamber 103 and the intake of the operating air to the second pressure action chamber 104 can be switched (hereinafter referred to as "switching of intake"). And by repeating the switching of intake, the piston 102 can reciprocate. Thus, 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 toward the second end 101b side, the operating rod 105 is driven in a manner of protruding from the double-acting cylinder 101, and conversely, when the piston 102 moves toward the first end 101a side, the operating rod 105 is driven in a manner of being pulled into the inside of the double-acting cylinder 101. Furthermore, the case where the operating rod 105 is driven to protrude from the double-acting cylinder 101 is referred to as driving in the forward direction, and conversely, the case where the operating rod 105 is driven to be housed in the double-acting cylinder 101 is referred to as driving in the backward direction.

[0048] The speed of the reciprocating motion of the operating rod 105 is controlled by adjusting the flow rate of the operating air using the flow rate adjustment parts 14A and 14B.

[0049] For example, when the movement speed of the operating lever 105 is controlled by adjusting the flow rate of the operating air discharged from the first pressure chamber 103 or the second pressure chamber 104 (exhaust throttling control), the check valves 141A and 141B of the flow adjustment parts 14A and 14B allow the flow of operating air from the switching valve 13 side to the fluid pressure actuator 10 side, while on the other hand, preventing the operating air from flowing in the opposite direction.

[0050] When the operating rod 105 is driven in the forward direction, the operating air is taken in from the first pipe 11 to the first pressure chamber 103. In this case, the check valve 141A of the flow regulating part 14A on the first pipe 11 allows the flow of the operating air to the first pressure chamber 103, so the operating air is fed to the first pressure chamber 103. Then, when the piston 102 moves in the forward direction, the operating air is exhausted from the second pressure chamber 104 to the second pipe 12. At this time, the operating air cannot pass through the check valve 141B of the flow regulating part 14B on the second pipe 12, so it passes through the flow regulating valve 142B. Therefore, the flow rate of the operating air is limited according to the valve opening of the flow regulating valve 142B, thereby controlling the moving speed of the piston 102 in the forward direction (that is, controlling the moving speed of the operating rod 105 in the forward direction).

[0051] Conversely, when the operating rod 105 is driven in the backward direction, the operating air is introduced into the second pressure chamber 104 from the second pipe 12. In this case, the check valve 141B of the flow regulating part 14B on the second pipe 12 allows the flow of the operating air to the second pressure chamber 104, so the operating air is supplied to the second pressure chamber 104. Then, when the piston 102 moves in the backward direction, the operating air is exhausted from the first pressure chamber 103 to the first pipe 11. At this time, the operating air cannot pass through the check valve 141A of the flow regulating part 14A on the first pipe 11, so it passes through the flow regulating valve 142A. Therefore, the flow rate of the operating air is limited according to the valve opening of the flow regulating valve 142A, thereby controlling the moving speed of the piston 102 in the backward direction (that is, controlling the moving speed of the operating rod 105 in the backward direction).

[0052] On the other hand, for example, when the movement speed of the operating lever 105 is controlled by adjusting the flow rate of the operating air supplied to the first pressure chamber 103 or the second pressure chamber 104 (intake throttling control), the check valves 141A and 141B of the flow adjustment parts 14A and 14B 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 opposite direction.

[0053] When the operating rod 105 is driven in the forward direction, compressed air is introduced into the first pressure chamber 103 from the first pipe 11. In this case, the operating air cannot pass through the check valve 141A of the flow regulating part 14A on the first pipe 11, so it is fed to the first pressure chamber 103 through the flow regulating valve 142A. Therefore, the flow rate of the operating air is limited according to the valve opening of the flow regulating valve 142A, thereby controlling the moving speed of the piston 102 in the forward direction (that is, controlling the moving speed of the operating rod 105 in the forward direction). Then, when the piston 102 moves in the forward direction, the operating air is exhausted from the second pressure chamber 104 to the second pipe 12. At this time, the check valve 141B of the flow regulating part 14B on the second pipe 12 allows the flow of the operating air to the switching valve 13.

[0054] Conversely, when the operating rod 105 is driven in the backward direction, the operating air is taken in from the second pipe 12 to the second pressure chamber 104. In this case, the operating air cannot pass through the check valve 141B of the flow adjustment part 14B on the second pipe 12, so it is fed to the second pressure chamber 104 through the flow adjustment valve 142B. Therefore, the flow rate of the operating air is limited according to the valve opening of the flow adjustment valve 142B, thereby controlling the moving speed of the piston 102 in the backward direction (that is, controlling the moving speed of the operating rod 105 in the backward direction). Then, when the piston 102 moves in the backward direction, the operating air is exhausted from the first pressure chamber 103 to the first pipe 11. At this time, the check valve 141A of the flow adjustment part 14A on the first pipe 11 allows the flow of the operating air to the switching valve 13.

[0055] 〈About the Condition Monitoring System〉 Next, the state monitoring system 1 will be described. Figure 1 As shown, the state monitoring system 1 mainly includes 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, 6B (an example of a sensor), a temperature sensor 7 (an example of a sensor) and a state monitoring device 5 (an example of a monitoring unit).

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

[0057] The first pressure sensor 3 is disposed between the flow regulating portion 14A on the first pipe 11 and the fluid pressure actuator 10. Thus, the first pressure sensor 3 detects the pressure value (an example of a physical quantity) in the first pipe 11. This is synonymous with detecting the pressure value (first pressure value) of the first pressure chamber 103. The reason is that, according to Pascal's law, the pressure on the inner wall of the first pressure chamber 103 is equal to the pressure on the inner wall of the first pipe 11 leading to the first pressure chamber 103.

[0058] In addition, the second pressure sensor 4 is disposed between the flow rate adjustment portion 14B on the second pipe 12 and the fluid pressure actuator 10. Thus, the second pressure sensor 4 detects the pressure value (an example of a physical quantity) in the second pipe 12. This is synonymous with detecting the pressure value (second pressure value) of the second pressure chamber 104. The reason is that, according to Pascal's law, the pressure on the inner wall of the second pressure chamber 104 is equal to the pressure on the inner wall of the second pipe 12 leading to the second pressure chamber 104.

[0059] The cylinder switches 6A and 6B are magnetic sensors that detect the approach of the piston 102 to the cylinder switch by sensing the magnetism of the magnet built into the piston 102. The cylinder switch 6A is provided on the first end 101a side of the double-acting cylinder 101. Thus, when the piston 102 is located on the first end 101a side, the cylinder switch 6A senses the piston 102 and sends an electrical signal. The cylinder switch 6B is provided on the second end 101b side of the double-acting cylinder 101. Thus, when the piston 102 is located on the second end 101b side, the cylinder switch 6B senses the piston 102 and sends an electrical signal. Therefore, when both the cylinder switch 6A and the cylinder switch 6B do not send an electrical signal, it means that the piston 102 is moving.

[0060] The temperature sensor 7 is a sensor such as a temperature measuring resistor, a thermistor, or a thermocouple, and is disposed near the fluid pressure actuator 10. The temperature sensor 7 is used to sense the temperature (an example of a physical quantity, hereinafter referred to as the ambient temperature) around the fluid pressure actuator 10. The temperature sensor 7 may also be built into the state monitoring device 5.

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

[0062] The calculation unit 51 monitors the operating state of the fluid pressure actuator 10 according to the state monitoring program based on the information input to the state monitoring device 5 from the controller 2, the pressure sensors 3, 4, the cylinder switches 6A, 6B, and the temperature sensor 7 (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 ​​in the form of analog signals, so the detection unit 52 converts the detected pressure values ​​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 and 6B, and the electric signals applied by the cylinder switches 6A and 6B to the controller 2 are input to the detection unit 52 in a branched manner. Thus, the state monitoring device 5 can grasp the time point when the cylinder switches 6A and 6B send out the electric signals. Furthermore, the detection unit 52 is electrically connected to the temperature sensor 7, so that the state monitoring device 5 can obtain information related to the ambient temperature.

[0065] Furthermore, the detection unit 52 is electrically connected to the controller 2, and the electric signal applied to the first solenoid 134A or the second solenoid 134B by the controller 2 is branched and input to the detection unit 52. Thus, the state monitoring device 5 can grasp the time when the electric signal is applied to the first solenoid 134A or the second solenoid 134B.

[0066] The internal clock 53 is used for measuring time, and can continue to measure time by means of the built-in battery of the status monitoring device 5 even when the power supply of the status monitoring device 5 is turned off.

[0067] The display unit 56 is, for example, an LED, and can display the operating state of the fluid pressure actuator 10 according to the operating state of the piston 102 and the time point when the air intake in the switching valve 13 is switched. In addition, as described later, the state monitoring device 5 can also display the content when it is determined that the fluid pressure actuator 10 has deteriorated.

[0068] The storage unit 57 stores a state monitoring program and can also store the results of calculations performed by the calculation unit 51. In addition, the communication unit 58 can communicate between the state monitoring device 5 and an electronic computer (PC 6) connected to the state monitoring device 5, for example, it can output the results of calculations performed by the calculation unit 51 to the PC 6.

[0069] 〈About the operation of the status monitoring program〉 The state monitoring system 1 constructed as described above converts the physical quantities input from the pressure sensors 3, 4, the cylinder switches 6A, 6B, and the temperature sensor 7 into data related to the performance of the fluid pressure actuator 10, i.e., performance values, and data related to the use conditions of the fluid pressure actuator 10, i.e., environmental values, in accordance with the state monitoring program, and monitors the state of the fluid pressure actuator 10 based on the performance values ​​and environmental values.

[0070] The so-called performance values ​​include data related to the performance of the fluid pressure actuator 10, such as response time, movement time of the piston 102, thrust acting on the piston 102 (hereinafter referred to as thrust), air consumption of the operating air in the cylinder (hereinafter referred to as air consumption), etc.

[0071] The so-called response time is the time from when the air intake 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 the electric signal is applied to the first solenoid 134A to when the cylinder switch 6A no longer issues an electric signal, or the time from when the electric signal is applied to the second solenoid 134B to when the cylinder switch 6B no longer issues an electric signal.

[0072] The so-called moving time is the time taken for the piston 102 to move from the first end 101a side to the second end 101b side (the time taken for the movement in the forward direction) in the double-acting cylinder 101 or the time taken for the piston 102 to move from the second end 101b side to the first end 101a side (the time taken for the movement in the backward direction) in the double-acting cylinder 101. Specifically, the state monitoring device 5 obtains the time from when the cylinder switch 6A stops sending an electric signal to when the cylinder switch 6B sends an electric signal or the time from when the cylinder switch 6B stops sending an electric signal to when the cylinder switch 6A sends an electric signal by measuring with the internal clock 53.

[0073] The thrust is a force applied to the piston 102 by the operating air in order to move the piston 102 in the forward pushing direction or the backward pulling direction. Specifically, the state monitoring device 5 calculates the difference between the 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 action chamber 103 obtained by the first pressure sensor 3 and the 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 action chamber 104 obtained by the second pressure sensor 4, thereby obtaining the thrust. The pressure receiving area is a value inherent to the fluid pressure actuator 10, and is used for 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 leakage of the operating air between the first pressure chamber 103 and the second pressure chamber 104. Specifically, the air consumption of the pneumatic device in normal state and after deterioration is calculated and compared based on the air flow rate measured by the flow sensor to obtain the air consumption.

[0075] The so-called environmental values ​​include data related 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 referred to as the supply pressure), the time to stop the fluid pressure actuator 10 (hereinafter referred to as the stop time), and the action cycle of the fluid pressure actuator 10 (hereinafter referred to as the action cycle).

[0076] As described above, 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 chamber 103 or the second pressure chamber 104, and is obtained by the first pressure sensor 3 or the second pressure sensor 4.

[0077] The stop time is the time when the piston 102 stops at the first end 101a side or the second end 101b side in the double-acting cylinder 101. Specifically, the state monitoring device 5 measures the length of time that the cylinder switch 6A or the cylinder switch 6B sends an electrical signal with the internal clock 53 to obtain the stop time.

[0078] The so-called action cycle is the action frequency of the fluid pressure actuator 10, which is the time from the start of the reciprocating motion of the piston 102 to the start of the next reciprocating motion. Specifically, the state monitoring device 5 measures the time between the reciprocating motion of the piston 102 sensed by the cylinder switch 6A and the cylinder switch 6B and the next reciprocating motion with the internal clock 53, thereby obtaining the action cycle.

[0079] First, each time the fluid pressure actuator 10 operates, the state monitoring device 5 acquires the above-mentioned performance value and environmental value, thereby generating time series data of the performance value and environmental value. Figure 2 This is a table showing an example of time series data of performance values ​​and environmental values. Figure 3A for Figure 2 The time series data of the movement time in the time series data of the performance value shown is graphed. Figure 3B This is a graph of the corrected values ​​of the time series data of the shift time.

[0080] Figure 2 The "count value" in the table includes information on "year, month, day", "hour, minute, second" and "number of actions". "Year, month, day" is the date when the fluid pressure actuator 10 is actuated. The record "230825" in the table means August 25, 2023. Secondly, "hour, minute, second" is the time when the fluid pressure actuator 10 is actuated on the date indicated by "year, month, day" (more specifically, the time when an electrical signal is applied from the controller 2 to the switching valve 13 in order to actuate the fluid pressure actuator 10). For example, "151200" in the table means 15:12:00. "Number of actions" is the cumulative number of actions of the fluid pressure actuator 10 on the date indicated by "year, month, day". For example, "2671" in the table means the 2671th action, and "2672" means the 2672nd action. Furthermore, "year, month, day", "hour, minute, second" and "number of actions" are all information obtained by the internal clock 53.

[0081] In summary, Figure 2 The first row of count values ​​in the table shown means that the 2671th action (reciprocating motion of the piston 102) of the fluid pressure actuator 10 was performed at 15:12:00 on August 25, 2023. Each time the piston 102 is moved in the forward push direction or the backward pull direction, the number of times of the action is counted. In this embodiment, each time the action in the forward push direction is performed is counted as 1 time.

[0082] In addition, the performance value and environmental value of the fluid pressure actuator 10 when performing the 2671st operation are recorded in Figure 2 The same row in the table. That is, the movement time in the 2671th action (the time spent moving in the backward pulling direction or the forward pushing direction, in the present embodiment, the time spent moving in the forward pushing direction) is 0.772 seconds. In addition, the maximum thrust and the average thrust are recorded for the thrust. That is, the maximum thrust in the 2671th action is 50.5N, and the average thrust in the 2671th action is 45.2N. In addition, the action cycle in the 2671th action is 11 seconds. In addition, the stop time in the 2671th action is 6 seconds. In other words, before starting the 2671th action, the action of the fluid pressure actuator 10 stopped for 6 seconds. Furthermore, the supply pressure in the 2671th action is 0.61Mpa, and the ambient temperature in the 2671th action is 30.5°C. In addition, the performance values ​​and environmental values ​​of the fluid pressure actuator 10 in the actions after the 2672nd time are also expressed in the same way. Figure 2 in the table.

[0083] The state monitoring device 5 (calculation unit 51) generates the above-described time series data in units of, for example, one day and stores the data in the storage unit 57. Figure 2 The table shown is an extract of data of the number of actions 2671 to 2688 in the time series data for one day, and data after the 2689th time are omitted. In addition, generating the time series data in units of one day is just an example, and the time series data may be generated in units of several hours, for example.

[0084] Furthermore, it is considered that the performance value will increase or decrease due to the deterioration of the fluid pressure actuator 10, so when the performance value reaches a predetermined threshold value, the state monitoring device 5 (calculation unit 51) determines that the fluid pressure actuator 10 has deteriorated. Specifically, for example, when the seal ring provided on the outer periphery of the piston 102 deteriorates, it is considered that the sliding property of the piston 102 is reduced and the air consumption of the operating air is increased. In this way, it is considered that the response time and the movement time are prolonged. In addition, when the lubricating oil for ensuring the sliding property of the piston 102 is dried up, it is also considered that the response time and the movement time are prolonged or the thrust required to move the piston 102 is increased due to the reduction in the sliding property of the piston 102. Therefore, when the performance value (response time, movement time, thrust, air consumption) reaches a threshold value, it is determined that some parts of the fluid pressure actuator 10 have deteriorated, and replacement with a new fluid pressure actuator 10 is urged. Furthermore, the above-mentioned threshold value may be a value determined according to the performance value required of the fluid pressure actuator 10, or a value that can be judged empirically that the degradation has deepened.

[0085] However, the performance value of the fluid pressure actuator 10 is sometimes affected by environmental values, so simply monitoring the performance value cannot accurately determine whether the fluid pressure actuator 10 has deteriorated.

[0086] Specifically, the viscosity of the lubricating oil is affected by the ambient temperature. When the viscosity of the lubricating oil changes, the sliding resistance changes, so it is considered that the response time, the moving time, and the thrust increase. In addition, if the stop time is long, the seal ring will push the lubricating oil away and come into close contact with the inner surface of the double-acting cylinder 101, and it is considered that the response time, the moving time, and the thrust increase. In this way, even if the degradation is not actually deepened, there is a risk that the performance value (response time, moving time, thrust, air consumption) exceeds the threshold.

[0087] For example, Figure 3A for Figure 2 The graph of the time series data of the movement time in the time series data of the performance values ​​shown in the table shows that the action time increases as the number of actions increases, and reaches the threshold value T11 around the time point t11. Figure 3A In the example, the action time decreases after the time point t11, so it can be considered that the threshold value T11 is reached near the time point t11 ​​due to the influence of the environmental value. Therefore, if the fluid pressure actuator 10 is simply judged to have deteriorated at the time point when the performance value reaches the threshold value T11, there is a risk of misjudgment.

[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 environment value using equation (1). Here, n in equation (1) represents the total number of two variable data (x, y), x i and i Indicates the value of each data. and Respectively represent the mean values ​​of the variables.

[0089] [Formula 1]

[0090] Specifically, the time series data of at least one performance value such as response time, movement time, thrust, air consumption, etc. are selected, and the correlation coefficient of each selected performance value with the time series data of at least one environmental value such as ambient temperature, supply pressure, stop time, action cycle, etc. is calculated.

[0091] Here, as an example, the moving time is selected from the performance values, and the correlation coefficients with the ambient temperature, supply pressure, and stop time in the environmental values ​​are calculated. More specifically, the correlation coefficients between the time series data of the moving time and the time series data of the ambient temperature, the correlation coefficients between the time series data of the moving time and the time series data of the supply pressure, and the correlation coefficients between the time series data of the moving time and the time series data of the stop time are calculated. Here, Figure 4A This is a graph showing the correlation between the time series data of the moving time and the time series data of the ambient temperature. Figure 4B This is a graph showing the correlation between the time series data of the travel time and the time series data of the supply pressure. Figure 4C This is a graph showing the correlation between the time series data of the moving time and the time series data of the stopping time.

[0092] according to Figure 4A The graph shown shows that the movement time decreases with the increase of the ambient temperature. The correlation coefficient is -0.85, which indicates that the movement time has a strong correlation with the ambient temperature.

[0093] according to Figure 4B The graph shown shows that there is no relationship between the travel time and the supply pressure such that when the value of one increases, the value of the other increases or decreases. The correlation coefficient is 0.03, and it is considered that the correlation between the travel time and the supply pressure is weak.

[0094] according to Figure 4C The graph shown shows that there is no relationship between the moving time and the stop time such that when the value of one increases, the value of the other increases or decreases. The correlation coefficient is 0.10, and it is considered that the correlation between the moving time and the stop time is weak.

[0095] As described above, by calculating the correlation coefficient, the strength of the correlation between the performance value and the environmental value can be observed, so the strength of the influence of the environmental value on the performance value can be understood. Therefore, if the influence is strong, it is known that the performance value is affected by the environmental value, so when an abnormality occurs in the performance value (moving speed in the above example), it can be determined that the cause is the influence of the environmental value (ambient temperature in the above example).

[0096] Next, the state monitoring device 5 (calculation unit 51) calculates a regression equation based on the time series data of the performance value and the time series data of the environment value, and uses the regression equation to correct the time series data of the performance value. This correction means finding a value (corrected value) after removing the influence of the environment value from the time series data of the performance value.

[0097] Specifically, at least one of the performance values ​​such as the moving time, thrust, and air consumption is corrected in such a way as to remove the influence of the environmental value having a strong influence. Here, the influence is judged to be strong when the absolute value of the correlation coefficient is greater than or equal to 0.3. In the above example, the absolute value of the correlation coefficient between the time series data of the moving time and the time series data of the ambient temperature is greater than or equal to 0.3, so a regression equation is calculated based on the time series data of the moving time and the time series data of the ambient temperature, and the time series data of the moving time is corrected by using the regression equation.

[0098] For example, in the case of (x i ,y i )(i=1, 2, ...n), assuming that equation (2) is satisfied, equation (3) is used to obtain the regression equation of equation (4). The regression line R11 represented by the regression equation is shown in FIG4(a). Here, β0 represents the intercept and β1 represents the slope.

[0099] [Formula 2] y i =β0+β1x i +e i ··· (2)

[0100] [Formula 3]

[0101] [Formula 4] β=(X T X) -1 X T Y ··· (4)

[0102] At this time, the estimated value under the reference condition x0 is expressed by equation (5).

[0103] [Formula 5] y0= β0+β1x0 ··· (5)

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

[0105] [Formula 6]

[0106] Then, the correction value of the measured value y (that is, the value from which the influence of the environmental value is removed) is expressed by equation (7) or equation (8).

[0107] [Formula 7]

[0108] [Formula 8]

[0109] The graph showing the effect of ambient temperature excluded from the time series data of the travel time is shown in Figure 3B .and Figure 3A Compared with the time series data (measured values) of the travel time shown, Figure 3B The corrected time series data of the moving time (corrected value) shown suppresses the increase of the moving time as time passes, and does not reach the threshold value T11 near the time point t11. Therefore, it is known that the measured value reaches the threshold value T11 due to the influence of the environmental value, not due to the deterioration of the fluid pressure actuator 10. In other words, as long as the corrected value of the performance value is monitored, the accurate performance of the fluid pressure actuator 10 without the influence of the environmental value can be grasped, and the misjudgment that the fluid pressure actuator 10 has deteriorated will not occur.

[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 the fluid pressure actuator 10 is first used) with the latest correction value, the deterioration state of the fluid pressure actuator 10 can be understood.

[0111] Furthermore, in the above example, the correction is explained in the form of an environmental value having an absolute value of a correlation coefficient of 0.3 or more among a plurality of selected environmental values, but the correction may be performed for an environmental value having the largest value of a correlation coefficient among a plurality of selected environmental values.

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

[0113] As an example, a case where thrust correction is performed will be described. Figure 5A for Figure 2 The time series data of the maximum thrust among the time series data of the performance values ​​shown in the table is graphed. Figure 5B This is a graph of the values ​​obtained by correcting the time series data of the maximum thrust using one environmental value. Figure 5C This is a graph of the correction values ​​from the multivariate regression of the time series data of maximum thrust.

[0114] according to Figure 5A In the graph shown, values ​​exceeding the threshold value T12 appear frequently, and it is unclear whether this is caused by degradation of the fluid pressure actuator 10. Therefore, the state monitoring device 5 (calculation unit 51) calculates the correlation coefficient between the time series data of the maximum thrust and the time series data of the environmental value.

[0115] Specifically, for example, ambient temperature, supply pressure, and stop time are selected from the environmental values, and the correlation coefficient between the time series data of each and the time series data of the maximum thrust is calculated. Fig. 6A This is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the ambient temperature. Figure 6B This is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the supply pressure. Figure 6C This is a graph showing the correlation between the time series data of the maximum thrust and the time series data of the stop time.

[0116] according to Fig. 6A The graph shown shows a negative correlation that thrust decreases as ambient temperature increases. The correlation coefficient is -0.88, indicating that there is a strong correlation between thrust and ambient temperature.

[0117] according to Figure 6B The graph shown shows that there is no relationship between thrust and supply pressure such that when the value of one increases, the value of the other increases or decreases. The correlation coefficient is 0.04, which indicates that the correlation between thrust and supply pressure is weak.

[0118] according to Figure 6C The graph shown shows that there is a positive correlation that the thrust increases as the stop time increases. The correlation coefficient is -0.40, indicating that there is a strong correlation between the thrust and the stop time.

[0119] For thrust, the absolute value of the correlation coefficient between the thrust and the ambient temperature and the absolute value of the correlation coefficient between the thrust and the stop time is greater than 0.3. Therefore, the state monitoring device 5 (calculation unit 51) performs multiple regression based on the time series data of the thrust and the time series data of the ambient temperature and the stop time to correct the time series data of the thrust. That is, the value after removing the influence of the ambient temperature and the stop time from the time series data of the thrust is obtained. The regression line R12 represented by the regression equation calculated based on the time series data of the maximum thrust and the time series data of the ambient temperature is shown in FIG. Fig. 6A The regression line R13 represented by the regression equation calculated from the time series data of the maximum thrust and the time series data of the stop time is shown in FIG. Figure 6C .

[0120] The graph showing the maximum thrust time series data after excluding only the effect of ambient temperature is shown in Figure 5B .and Figure 5A Compared with the time series data (measured values) of the maximum thrust shown in Figure 5BThe corrected maximum thrust time series data (corrected value) shown suppresses data variation, but contains a large amount of data exceeding the threshold value T12. This is because the performance of the fluid pressure actuator 10 cannot be accurately grasped due to the influence of the dead time with a large correlation coefficient.

[0121] Furthermore, the graph after further eliminating the effect of the stop time is shown in Figure 5C Compared to Figure 5B As for the correction value shown, the deviation of the data is further suppressed, and the data exceeding the threshold value T12 no longer exists. Therefore, it is known that the measured value reaches the threshold value T12 due to the influence of the environmental value (ambient temperature and stop time), not due to the deterioration of the fluid pressure actuator 10. In this way, by monitoring the correction value under the multiple regression, the performance of the fluid pressure actuator 10 can be accurately grasped without the influence of the environmental value, and the misjudgment that the fluid pressure actuator 10 has deteriorated will not occur.

[0122] As described above, according to the state monitoring system 1 of this embodiment, A state monitoring system 1 for (1) monitoring the operating state of a pneumatic device (e.g., a fluid pressure actuator 10) that operates with operating air as a driving source, characterized in that it comprises: 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 unit (e.g., a state monitoring device 5) having a state monitoring program, wherein the state monitoring program is used to convert the physical quantities (e.g., pressure values, ambient temperature, time) acquired by the sensors into performance-related data of the pneumatic device (fluid pressure actuator 10), i.e., performance values, and data related to usage conditions of the pneumatic device (fluid pressure actuator 10), i.e., environmental values, to generate time series data of the performance values ​​and time series data of the environmental values, and to calculate 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 status monitoring system 1 described in (1), the pneumatic device (fluid pressure actuator 10) preferably has a piston 102 that slides in a cylinder (for example, a double-acting cylinder 101) with the help of operating air, and the performance value includes at least any one of the response time of the pneumatic device (fluid pressure actuator 10), the movement time of the piston 102, the thrust applied to the piston 102 by the operating air, and the air consumption of the operating air in the cylinder (double-acting cylinder 101), and the environmental value includes at least any one of the temperature around the pneumatic device (fluid pressure actuator 10), namely the ambient temperature, the pressure of the operating air supplied to the pneumatic device (fluid pressure actuator 10), namely the supply pressure, the time to stop the pneumatic device (fluid pressure actuator 10), namely the stop time, and the action cycle of the pneumatic device (fluid pressure actuator 10).

[0124] According to the above-mentioned state monitoring system 1, 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), the strength of the influence of the environmental value on the performance value can be grasped. If the influence is strong, it is known that the performance value is affected by the environmental value, so when an abnormality occurs in the performance value, it can be determined that the cause is the influence of the environmental value.

[0125] More specifically, if at least one of the environmental values ​​such as ambient temperature, supply pressure, stop time, and action cycle (hereinafter referred to as 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 referred to as specific performance value), when an abnormality occurs in the specific performance value, it can be determined that the cause is the influence of the specific environmental value (for example, if the ambient temperature has a strong influence on the movement time, when an abnormality occurs in the movement time, it can be determined that the cause is the influence of the ambient temperature). Therefore, the state monitoring of the pneumatic device (fluid pressure actuator 10) can be appropriately performed.

[0126] (3) In the status monitoring system 1 described in (1) or (2), the status monitoring program preferably calculates a regression equation (e.g., regression lines R11, R12, R13) based on the time series data of the performance values ​​and the time series data of the environmental values, and corrects the performance values ​​with the aid of the regression equation (regression lines R11, R12, R13).

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

[0128] According to the above-mentioned state monitoring system 1, since the performance value is corrected by means of the regression equation (regression lines R11, R12, R13), the performance of the accurate pneumatic device (fluid pressure actuator 10) without the influence of the environmental value can be grasped. As a result, the deterioration state of the pneumatic device (fluid pressure actuator 10) can be accurately grasped. Therefore, the pneumatic device (fluid pressure actuator 10) can be maintained at an appropriate time or improved by rationalizing the use conditions of the pneumatic device. Furthermore, it is possible to prevent the device (robot arm, etc.) using the pneumatic device (fluid pressure actuator 10) from stopping unexpectedly. In addition, the pneumatic device (fluid pressure actuator 10) can be used as long as possible before deterioration, reducing the frequency of maintenance. Furthermore, the energy loss used to drive the pneumatic device (fluid pressure actuator 10) can be suppressed to a minimum.

[0129] Here, it is ideal 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 greater than 0.3, it is judged 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 greater than 0.3, correction is performed to exclude the influence of the specific environmental value from the specific performance value (for example, when the correlation coefficient between the moving time and the ambient temperature is greater than 0.3, correction is performed to exclude the influence of the ambient temperature from the moving time). The reason why correction is performed when the absolute value of the correlation coefficient is greater than 0.3 is because the inventors have confirmed through experiments that the environmental value with a correlation coefficient less than 0.3 has a small influence on the performance value.

[0130] Furthermore, in order to solve the above-mentioned problems, the state monitoring method of the present invention has the following configuration.

[0131] (5) A state monitoring method for monitoring the operating state of a pneumatic device (fluid pressure actuator 10) that uses operating air as a driving source for its operation, characterized in that data related to the performance of the pneumatic device (fluid pressure actuator 10), i.e., performance values, and data related to the use conditions of the pneumatic device (fluid pressure actuator 10), i.e., environmental values, are obtained, time series data of the performance values ​​and time series data of the environmental values ​​are generated, and a correlation coefficient between the time series data of the performance values ​​and the time series data of the environmental values ​​is calculated.

[0132] (6) In the state monitoring method described in (5), the pneumatic device (fluid pressure actuator 10) preferably has a sliding part (for example, a piston 102) that is actuated by operating air, and the performance value includes at least any one of the response time of the pneumatic device (fluid pressure actuator 10), the movement time of the sliding part (piston 102), the thrust exerted by the operating air on the sliding part (piston 102), and the air consumption of the operating air in the pneumatic device (fluid pressure actuator 10); and the environmental value includes at least any one of the temperature around the pneumatic device (fluid pressure actuator 10), namely the ambient temperature, the pressure of the operating air supplied to the pneumatic device (fluid pressure actuator 10), namely the supply pressure, the time to stop the pneumatic device (fluid pressure actuator 10), namely the stop time, and the action cycle of the pneumatic device (fluid pressure actuator 10).

[0133] According to the above-mentioned state monitoring method, 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), the strength of the influence of the environmental value on the performance value can be grasped. If the influence is strong, it is known that the performance value is affected by the environmental value, so when an abnormality occurs in the performance value, it can be determined that the cause is the influence of the environmental value.

[0134] More specifically, if at least one of the environmental values ​​such as ambient temperature, supply pressure, stop time, and action cycle (hereinafter referred to as 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 referred to as specific performance value), when an abnormality occurs in the specific performance value, it can be determined that the cause is the influence of the specific environmental value (for example, if the ambient temperature has a strong influence on the movement time, when an abnormality occurs in the movement time, it can be determined that the cause is the influence of the ambient temperature). Therefore, the state monitoring of the pneumatic device (fluid pressure actuator 10) can be appropriately performed.

[0135] (7) In the status monitoring method described in (5) or (6), it is preferred to calculate a regression equation (e.g., 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 to correct the performance value with the aid of the regression equation (regression lines R11, R12, R13).

[0136] (8) In the state monitoring method described in (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 state monitoring method, since the performance value is corrected by means of the regression equation (regression lines R11, R12, R13), the performance of the accurate pneumatic device (fluid pressure actuator 10) without the influence of the environmental value can be grasped. As a result, the degradation state of the pneumatic device (fluid pressure actuator 10) can be accurately grasped. Therefore, the maintenance of the pneumatic device (fluid pressure actuator 10) can be performed at an appropriate time. Furthermore, it is possible to prevent the device (robot arm, etc.) using the pneumatic device (fluid pressure actuator 10) from stopping unexpectedly. In addition, the pneumatic device (fluid pressure actuator 10) can be used as long as possible before deterioration, reducing the frequency of maintenance. Furthermore, the energy loss used to drive the pneumatic device (fluid pressure actuator 10) can be suppressed to a minimum.

[0138] Here, it is ideal 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 greater than 0.3, it is judged 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 greater than 0.3, correction is performed to exclude the influence of the specific environmental value from the specific performance value (for example, when the correlation coefficient between the moving time and the ambient temperature is greater than 0.3, correction is performed to exclude the influence of the ambient temperature from the moving time). The reason why correction is performed when the absolute value of the correlation coefficient is greater than 0.3 is because the inventors have confirmed through experiments that the environmental value with a correlation coefficient less than 0.3 has a small influence on the performance value.

[0139] Furthermore, the present embodiment is only an example and does not limit the present invention in any way. Therefore, the present invention can of course be improved and deformed in various ways without departing from its main purpose. For example, the state monitoring device 5 can also monitor the operating states of multiple fluid pressure actuators 10. In addition, the state monitoring device 5 can also monitor the switching valve 13. In addition, the pressure sensors 3 and 4 are described in the form of being arranged on the first pipe 11 and the second pipe 12, but are not limited to this and can also be built into the state monitoring device 5. In addition, the fluid pressure actuator 10 does not necessarily have to have an operating rod 105, and can also be applied to actuators with double-acting cylinders such as parallel manipulators. In addition, the state monitoring device 5 is described as an example of a monitoring unit, but the pressure sensors 3 and 4 can also have the same function as the state monitoring device 5. Description of the label

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

Claims

1. A state monitoring system for monitoring the operating state of a pneumatic device that uses operating air as a driving source, characterized in that: have: A sensor for acquiring a physical quantity reflecting the operating state and use environment of the pneumatic device; and A monitoring unit, which has a state monitoring program, wherein the state monitoring program is used to convert the physical quantity acquired by the sensor into data related to the performance of the pneumatic equipment, namely, performance values, and data related to the use conditions of the pneumatic equipment, namely, environmental values, generate time series data of the performance values ​​and time series data of the environmental values, and calculate the correlation coefficient between the time series data of the performance values ​​and the time series data of the environmental values.

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

3. The state monitoring system according to claim 1 or 2, characterized in that: The state monitoring program calculates a regression equation based on the time series data of the performance value and the time series data of the environment value. The correction of the property value is carried out with the aid of the regression equation.

4. The state monitoring system according to claim 3, characterized in that: The state 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.

5. A method for monitoring the operating state of a pneumatic device that uses operating air as a driving source, characterized in that: Acquire performance-related data of the pneumatic device, i.e., performance values, and use condition-related data of the pneumatic device, i.e., environmental values, generating time series data of the performance value and time series data of the environment value, A correlation coefficient between the time series data of the performance value and the time series data of the environment value is calculated.

6. The state monitoring method according to claim 5, characterized in that: The pneumatic device includes a sliding part that is moved by the operating air. The performance value includes at least any one of a response time of the pneumatic device, a movement time of the sliding part, a thrust force exerted by the operating air on the sliding part, and an air consumption of the operating air in the pneumatic device. The environmental value includes at least any one of the ambient temperature which is the temperature around the pneumatic device, the supply pressure which is the pressure of the operating air supplied to the pneumatic device, the stop time which is the time to stop the pneumatic device, and the operation cycle of the pneumatic device.

7. The state monitoring method according to claim 5 or 6, characterized in that: A regression equation is calculated based on the time series data of the performance value and the time series data of the environment value. The correction of the property value is carried out with the aid of the regression equation.

8. The state monitoring method according to claim 7, characterized in that: The correction is performed when the absolute value of the correlation coefficient is 0.3 or more.

Images