Control device and control system

Abstract

The present invention provides a control device that can continue operating without stopping its operation depending on the abnormal condition of the rotary coupling. [Solution] The control device (20) controls the operation of a rotary joint (10) whose rotation angle can be measured by magnetic detection. The control device includes a determination unit (230) that determines the state of the rotary joint based on the rate of change per unit time of the magnetic measurement value when the magnetic measurement value measured in magnetic detection is outside a predetermined range. The control device also includes an operation control unit (240) that controls the operation of the rotary joint based on the determination of the determination unit.

Description

Technical Field

[0001] The present invention relates to a control device for a rotary joint and a control system.

Background Art

[0002] Conventionally, a control device that measures the angle of a rotating body such as a rotary joint and controls the operation of the rotating body according to the measurement result, and a control system including a rotary joint and the control device are known.

[0003] Regarding this, Patent Document 1 discloses a control mechanism that detects the rotation angle of a turntable and controls the operation of the turntable according to the detected value.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional control devices such as those described in Patent Document 1 may have a mechanism to stop the operation of the rotary joint when the measurement result of the angle of the rotary joint is an abnormal value. However, such a control device cannot determine whether the abnormality of the rotary joint is due to an instantaneous change that requires the control device to be stopped, or a gradual change such as an abnormal object volume or aging that can be dealt with by subsequent maintenance. Therefore, the technique described in Patent Document 1 has a problem that the operation of the control device may be stopped even when the abnormality of the rotary joint is a gradual change that does not require the operation of the control device to be stopped. Note that the instantaneous or gradual change of the rotary joint described above is, for example, a change in a physical quantity. The physical quantity is, for example, the magnetic field strength detected or measured in the rotary joint.

[0006] The present invention has been made in view of these problems, and its objective is to provide a control device and control system that can continue the operation of a rotary joint without stopping its operation depending on the abnormal condition of the rotary joint. [Means for solving the problem]

[0007] To solve the above problems, the control device is a control device that controls the operation of a rotary joint to which a magnetic sensor capable of measuring the rotation angle by magnetic detection is attached, and comprises a determination unit that determines the state of the rotary joint based on the amount of change per unit time of the measured magnetic value when the measured magnetic value measured in the magnetic detection is outside a predetermined range, and an operation control unit that controls the operation of the rotary joint based on the determination of the determination unit.

[0008] Furthermore, the determination unit may determine that the state of the rotary joint has instantaneously become abnormal if the amount of change per unit time of the measured magnetic value is greater than or equal to a threshold, or determine that the state of the rotary joint has gradually become abnormal if the amount of change per unit time of the measured magnetic value is less than the threshold. Furthermore, if the determination unit determines that the amount of change per unit time of the measured magnetic value is greater than or equal to the threshold, the operation control unit may control the operation of the rotary joint so as to transition the state of the rotary joint to a predetermined stable state and then stop the operation of the rotary joint. Furthermore, the rotary coupling may also include a magnet and a magnetic angle sensor that detects the magnetic flux generated by the magnet and measures the magnetic field strength and the rotation angle, and the measured value related to the magnetism may be the magnetic field strength measured by the angle sensor. The control system also includes a rotary joint having a rotor, a shaft rotatably connected to the rotor's central axis as the axis of rotation, and a measuring unit that measures the rotation angle between the rotor and the shaft with respect to the central axis as the axis of rotation by magnetic detection; a determination unit that determines the state of the rotary joint based on the rate of change per unit time of the magnetic measurement value when the magnetic measurement value measured by the measuring unit is outside a predetermined range; and a control device having an operation control unit that controls the operation of the rotary joint based on the determination of the determination unit. [Effects of the Invention]

[0009] According to the above control device, the operation of the rotary coupling can continue without stopping it, depending on the abnormal condition of the rotary coupling. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the overall configuration of the control system according to this embodiment. [Figure 2] This is a cross-sectional view of the rotary joint shown in Figure 1, along the line II-II. [Figure 3] Figure 2 is a cross-sectional view of the rod, magnet, and measuring section along the line II-II shown. [Figure 4] This figure shows the functional configuration of the control device shown in Figure 1. [Figure 5A] Figure 2 shows a cross-sectional view along line II-II when the rotary joint shown in the figure instantaneously enters an abnormal state. [Figure 5B] Figure 2 shows a cross-sectional view along line II-II when the rotary joint gradually enters an abnormal state. [Figure 6A] Figure 2 is a graph showing the time transition of magnetic field strength when the rotary coupling 10 instantaneously enters an abnormal state. [Figure 6B] Figure 2 is a graph showing the time transition of magnetic field strength when the rotary coupling 10 gradually enters an abnormal state. [Figure 7] Figure 1 is a flowchart showing an example of the processing flow of the control system. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described with reference to the attached drawings. To facilitate understanding of the description, the same reference numerals are used for the same components and steps in each drawing whenever possible, and redundant explanations are omitted.

[0012] Figure 1 is a diagram showing the overall configuration of the control system 1 according to this embodiment. Figure 2 is a cross-sectional view of the rotary joint 10 shown in Figure 1 along line II-II. Figure 3 is a cross-sectional view of the rod 14, magnet 15, and measuring unit 16 shown in Figure 2 along line II-II. As shown in Figures 1 to 3, the control system 1 is composed of a measuring unit 16 that measures the rotation angle by magnetic detection in the rotary joint 10 and a control device 20. In this embodiment, the first direction along the Z axis is perpendicular to the installation surface of the rotary joint 10 and extends from the lower end of the rotary joint 10 towards the upper end along the central axis O. The second direction along the X axis is perpendicular to the Z axis and extends from the connection port 116B on the outer circumference of the pipe 111B of the flange 11 towards the connection port 116A on the outer circumference of the pipe 111A. The third direction along the Y axis is perpendicular to the Z axis and extends towards the front.

[0013] The rotary joint 10 is, for example, a swivel joint. The rotary joint 10 has its lower part mounted on a base member (not shown) of a hydraulic device (not shown), and its upper part, which is rotatably connected to the lower part, is connected to a swivel member (not shown) of the hydraulic device. The swivel member of the hydraulic device is assumed to be rotatably connected to the base member of the hydraulic device. The rotary joint 10 supplies oil flowing in from the swivel member to the base member via an oil passage, or supplies oil flowing in from the base member to the swivel member via an oil passage. The rotary joint 10 is also configured to measure the rotation angle between the upper and lower parts. Details of the configuration of the rotary joint 10 will be explained later, so the explanation is omitted here.

[0014] The control device 20 is an information processing device that controls the operation of the rotary joint 10. The control device 20 includes a storage device 23 that stores various programs, various information, and information on processing results necessary for the execution of processing in the processor 21. Further, the control device 20 is configured to include a processor 21 that functions as various functional means by executing a predetermined program stored in the memory 22 or the storage device 23 or the like. Furthermore, the control device 20 is configured to include a memory 22 that temporarily stores a predetermined program and data necessary when the processor 21 executes the predetermined program, and a communication device 24 for communicating with an external device. In addition, the control device 20 is configured to include an input / output device 25 that receives an input for the operator of the control device 20 to perform an operation on the control device 20 and displays information provided from the control device 20 to the operator. Note that the input / output device 25 does not necessarily have to be included in the control device 20 and may be provided separately. Note that the control device 20 may be composed of a single information processing device or may be composed of a plurality of information processing devices. Also, when the control device 20 is composed of a plurality of information processing devices, it may be composed of a device that controls the operation of the rotary joint 10 and a server device or another terminal device connected through a network, cloud, or the like to the device.

[0015] Also, the program according to the embodiment causes a computer (processor 21) to execute each process and each control of the information processing device according to the embodiment. The recording medium according to the embodiment is a non-temporary recording medium (storage medium) readable by a computer on which the program according to the embodiment is recorded.

[0016] The processor 21 includes circuits such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), and programmable logic devices (e.g., SPLD (Simple Programmable Logic Device), CPLD (Complex Programmable Logic Device), FPGA (Field Programmable Gate Array)). The processor 21 realizes the functions according to the embodiments by, for example, reading and executing a program stored in the storage circuit or storage device 23. The storage circuit or storage device 23 may be included in the processor 21. Also, the storage circuit or storage device 23 may be provided outside the processor 21.

[0017] Subsequently, details of the configuration of the rotary joint 10 will be described. As shown in FIGS. 2 and 3, the rotary joint 10 includes, for example, a flange 11, a rotor 12, a shaft 13, a rod 14, a magnet 15, and a measurement unit 16.

[0018] The flange 11 is a member for fixing the rotary joint 10 to the installation surface of the rotary joint 10. The flange 11 includes, for example, a plate-like portion and a cylindrical portion. The cylindrical portion is provided near the center along the Y-axis on the bottom surface side of the plate-like portion. Here, the vicinity indicates a range with an upper limit of, for example, about one-tenth of the length of the plate-like member along the Y-axis. The cylindrical member extends such that one of both ends faces the second direction side and the other end faces the direction opposite to the second direction. The flange 11 is provided with a hole 115 that penetrates the plate-like portion and the cylindrical portion from the upper surface to the bottom surface of the flange 11 at the center of the plate-like portion when viewed from the first direction.

[0019] The flange 11 has two connection ports 117A and 117B around the hole 115. The flange 11 has a connection port 116A on one end of the cylindrical portion on the second direction side, which connects to the connection port 117A via a conduit 111A. The flange 11 also has a connection port 116B on the other end of the cylindrical portion on the opposite side of the second direction, which connects to the connection port 117B via a conduit 111B. The conduit 111A, which goes from the connection port 116A to the recess via the connection port 117A, functions as a drain oil passage or pilot oil passage for draining drain oil into the rotary joint 10. The conduit 111B, which goes from the connection port 116B to the recess via the connection port 117B, also functions as a drain oil passage or pilot oil passage for draining drain oil into the rotary joint 10.

[0020] The rotor 12 is cylindrical and supplies oil flowing in from the shaft 13 to a base member (not shown) of hydraulic equipment (not shown) connected to the outer circumference of the rotor 12 via oil passages provided inside the rotor 12. The oil flowing into the shaft 13 is, for example, supply oil to the hydraulic motor, return oil from the hydraulic motor, and pilot oil. The oil passages provided inside the rotor 12 are, for example, supply oil passages to the hydraulic motor, return oil passages from the hydraulic motor, and pilot oil passages. One end of the rotor 12, on the bottom side opposite to the first direction, is connected to the upper side of the plate-shaped portion of the flange 11, thereby connecting the rotor 12 and the flange 11. The rotor 12 is rotatable about the central axis O, with the outer circumference of the shaft 13 connected to the inner circumference.

[0021] The rotor 12 has oil passages 121A to 121G between its outer and inner circumference for supplying oil flowing in from the shaft 13 to the base member of the hydraulic equipment connected to the outer circumference of the rotor 12. The oil passages 121A to 121G are conduits connecting the oil passages on the inner circumference of the rotor 12 to the connection ports on the outer circumference. The oil passages 121A to 121G on the inner circumference are connected to the corresponding connection ports on the outer circumference of the shaft 13. In addition, the connection ports on the outer circumference of the oil passages 121A to 121G are connected to the corresponding connection ports on the base member of the hydraulic equipment.

[0022] The shaft 13 is cylindrical, and a swivel member (not shown) of the hydraulic equipment is connected to its upper surface. The shaft 13 supplies oil flowing in from a component on the swivel member (not shown) to the rotor 12 connected to the outer circumference of the shaft 13 via an oil passage provided inside the shaft 13. The shaft 13 also discharges oil flowing in from the flange 11 via a hole 132 provided inside the shaft 13 through a discharge hole 134 provided on the outer circumference of the shaft 13.

[0023] The shaft 13 is rotatable around the central axis O of the rotor 12, with its lower outer circumference connected to the inner circumference of the rotor 12. The lower part of the shaft 13 is the portion opposite to the first direction. The shaft 13 also has a recess 133 at one end, the lower end, centered on the central axis O. The shaft 13 is rotatable around the central axis O, with the other end opposite to the first direction connected to the upper surface of the flange 11. The recess 133 is rotatable around the central axis O, with the pipes 111A and 111B of the flange 11 connected. The shaft 13 also has a hole 132 extending from the recess 133 along the central axis O to the other end of the upper part, which is on the first direction side. The shaft 13 also has a discharge hole 134 extending from the hole 132 to the outer circumference of the upper part of the shaft 13. The hole 132, the recess 133, and the discharge hole 134 function as oil passages together with the pipelines 111A and 111B of the flange 11.

[0024] The shaft 13 has connection ports 131A to 131D around the hole 132 on its upper surface, allowing oil to flow between the shaft 13 and the swivel member of the hydraulic equipment. The shaft 13 also has connection ports 131E and 131F on its upper outer circumference, allowing oil to flow between the shaft 13 and the swivel member of the hydraulic equipment. Each of the connection ports 131A to 131F is connected via an oil passage (not shown) located inside the shaft 13 to a corresponding oil passage among a plurality of oil passages located on the lower outer circumference.

[0025] The shaft 13 is provided so that the rod 14 is not in direct contact with the inner circumference of the hole 132, from one end opposite to the first direction, via the recess in the flange 11 and the recess 133 of the shaft 13. The measuring portion 16 of the shaft 13 is connected to the hole 132 from the other end, which is on the first direction side, for example by screwing it in.

[0026] The rod 14 is cylindrical in shape, and one end opposite to the first direction is connected to the hole 115 of the flange 11 via a fixing member. The rod 14 extends from one end of the shaft 13 along the central axis O, and is positioned within the hole 132 so that the portion between the two ends does not directly contact the inner circumference of the hole 132. A magnet 15 is provided on the upper surface of the other end of the rod 14.

[0027] The magnet 15 is, for example, a permanent magnet and generates a magnetic field. The magnet 15 is provided on the upper surface of the other end of the rod 14. The magnet 15 is used by the measuring unit 16 to measure the rotation angle with respect to the central axis O between the shaft 13 and the rod 14 as the axis of rotation.

[0028] The measuring unit 16 is, for example, a magnetic angle sensor that measures the rotation angle between the rod 14 and the shaft 13, with the central axis O as the axis of rotation. The measuring unit 16 sends the measured rotation angle as an electrical signal to the control device 20. The measuring unit 16 is composed of a magnetic sensor 161, a case 162, and a fixing member 163.

[0029] The case 162 is formed in a cylindrical shape. The outer circumference of the case 162 is connected to the inner circumference of the hole 132, for example by screwing, so that it extends from the other end of the shaft 13 toward the other end of the rod 14. The case 162 is provided with a magnetic sensor 161 on one end of the case 162 that is opposite to the first direction. The outer circumference of the fixing member 163 is connected to the inner circumference of the other end of the case 162 that is on the first direction side. The case 162 sends signals output from the magnetic sensor 161 to the control device 20 via signal lines provided inside, the fixing member 163, and an external communication cable.

[0030] The magnetic sensor 161 is a sensor that measures magnetic field strength and rotation angle based on the magnetic field generated from the magnet 15. The magnetic sensor 161 is mounted on a surface at one end of the measuring unit 16 such that the measuring surface faces the magnet 15. For example, the magnetic sensor 161 is positioned at a distance (e.g., approximately 3.0 mm) from the surface of the magnet 15 on the first direction side where the measuring surface is located, allowing the magnetic sensor 161 to detect changes in the magnetic field. The magnetic sensor 161 detects magnetic flux using two magnetic detection elements mounted on the measuring surface in mutually perpendicular orientations. The magnetic sensor 161 measures the rotation angle between the rod 14 and the shaft 13, with the central axis O as the axis of rotation, from the ratio of the two detected magnetic flux values. The magnetic sensor 161 also measures the magnetic field strength by calculating the square root of the sum of the squares of the two detected magnetic flux values. The magnetic sensor 161 then outputs the measurement result as an electrical signal to the control device 20 via the signal lines of the case 162, the fixing member 163, and an external communication cable. In this embodiment, the magnetic sensor 161 measures the rotation angle and magnetic field strength, but is not limited to this. It may also transmit the detected magnetic flux value to the control device 20, and the control device 20 may calculate the rotation angle and magnetic field strength.

[0031] The fixing member 163 is a member for fixing the communication cable connecting the rotary joint 10 and the control device 20 to the rotary joint 10. One end of the fixing member 163 is connected to the inner circumference of the other end of the case 162, which is on the first direction side, by screwing or fitting, and the other end is connected to the communication cable.

[0032] <Functional configuration> The configuration of the rotary joint 10 has been described above. Next, the functional configuration of the control device 20 will be described. Figure 4 is a diagram showing the functional configuration of the control device 20 shown in Figure 1. As shown in Figure 4, the control device 20 is functionally configured to include a storage unit 210, an acquisition unit 220, a determination unit 230, and an operation control unit 240. The functional configuration of the control device 20 other than the storage unit 210 is realized by the processor 21 executing a program stored in the storage device 23, etc.

[0033] The memory unit 210 has a functional configuration that stores measurement data 211 and condition data 212.

[0034] The measurement data 211 consists of time-dependent data of magnetic field strength included in the measurement results measured by the magnetic sensor 161 of the measurement unit 16.

[0035] Condition data 212 is data used by the determination unit 230 to determine the state of the rotary joint 10. Condition data 212 includes a first threshold and a second threshold for a predetermined range. The predetermined range is a reference range indicating that the magnetic field strength measured by the measurement unit 16 is a normal value, and the first threshold includes at least one value from an upper limit and a lower limit. For example, the predetermined range may have only a lower limit defined as the first threshold, with no upper limit set. Alternatively, the predetermined range may have only an upper limit defined as the first threshold, with no lower limit set. Alternatively, the predetermined range may have both an upper and lower limit defined as the first threshold. The second threshold is a reference value used to determine whether the state of the rotary joint 10 became abnormal instantaneously or gradually.

[0036] The acquisition unit 220 acquires the measurement results transmitted from the measurement unit 16 of the rotary coupling 10. The acquisition unit 220 stores the measured values ​​related to magnetic field strength from the acquired measurement results in the measurement data 211 of the storage unit 210.

[0037] The determination unit 230 determines the state of the rotary joint 10 based on the rate of change of the measured value per unit time when the measured value of the rotary joint 10 is outside a predetermined range. Specifically, the determination unit 230 refers to the measurement data 211 stored in the storage unit 210. If the measured value indicated by the measurement data 211 is outside a predetermined range and the rate of change of the measured value per unit time is greater than or equal to the second threshold, the determination unit 230 determines that the state of the rotary joint 10 has become abnormal instantaneously. Furthermore, if the measured value indicated by the measurement data 211 is outside a predetermined range and the rate of change of the measured value per unit time is less than the second threshold, the determination unit 230 determines that the state of the rotary joint 10 has become abnormal gradually. As described above, the predetermined range is a reference range indicating that the magnetic field strength measured by the measurement unit 16 is a normal value, and the first threshold includes at least one value from the upper limit and the lower limit. The second threshold is a reference value that determines whether the state of the rotary joint 10 became abnormal instantaneously or gradually when it becomes abnormal. Furthermore, as described above, the second threshold value is a criterion for determining whether the rotary coupling 10 became abnormal instantaneously or gradually. In addition, the determination unit 230 notifies the operator or user of the control system 1 of the determination result. The determination unit 230 may also, after notifying that the condition became abnormal gradually, notify the operator to perform maintenance on the rotary coupling 10.

[0038] Examples of notifications that gradually become abnormal include the illumination or flashing of light-emitting parts (not shown), the output of warning sounds or error messages from the audio output unit, or the display of error messages from the text display unit, all of which warn of the possibility of an angle detection malfunction.

[0039] Furthermore, when determining the rate of change of the magnetic field strength value per unit time, the determination unit 230 may use statistical values ​​such as the median or average value within a unit period calculated at predetermined intervals, rather than the measured value itself. Also, the first threshold, the second threshold, the determination result, and the measurement data 211 are stored in any storage means. The arbitrary storage means is, for example, the storage unit 210. The arbitrary storage means may also include an external storage device. In addition, the first threshold, the second threshold, the determination result, and the measurement data 211 do not necessarily each need to be stored in the same storage unit.

[0040] Here, with reference to Figure 5A, an example of a case in which the rotary joint 10 instantaneously enters an abnormal state will be described. Figure 5A is a cross-sectional view along line II-II in the case in which the rotary joint 10 shown in Figure 2 instantaneously enters an abnormal state. In Figure 5A, the rotary joint 10 is in a state where the case 162 of the measuring part 16 is damaged because the measuring surface of the magnetic sensor 161 is pressed in the first direction by the pressure of the oil in the hole 132, and the measuring surface of the magnetic sensor 161 is tilted instead of being perpendicular to the central axis O. Note that instantaneous abnormalities are not limited to tilting. For example, consider a configuration in which the magnetic sensor 161 is covered with a sealing part (mold, etc.) not shown, and a situation is assumed in which pressure (leaked pressurized oil, etc.) is applied that causes at least a part of the mold to be damaged. In such a case, the magnetic sensor 161 may instantly move away from the magnet 15 even if it is not tilted, and this case also falls under the category of an instantaneously abnormal state. Although an example with a sealing portion has been described, it goes without saying that even without a sealing portion, the magnetic sensor 161 may instantly move away from the magnet 15 without tilting. The same applies to the case where the magnetic sensor 161 falls off in other examples. Furthermore, if the rotary joint 10 instantly enters an abnormal state, the operation control unit 240 controls the rotary joint 10 to transition it to a stable state and then stop its operation. The processing by the operation control unit 240 will be described later, so its explanation is omitted here.

[0041] Next, with reference to Figure 5B, an example of a case in which the rotary joint 10 gradually becomes abnormal will be described. Figure 5B is a cross-sectional view along line II-II in the case where the rotary joint 10 shown in Figure 2 gradually becomes abnormal. In Figure 5B, foreign matter 30 such as iron powder is attached to and accumulated on the first direction side of the magnet 15 of the rotary joint 10. In Figure 5B, the rotary joint 10 gradually becomes abnormal due to the gradual accumulation of foreign matter 30 inside the rotary joint 10, but another example is when the rotary joint 10 gradually becomes abnormal due to deterioration over time. Another example is when the magnet 15 gradually becomes abnormal due to deterioration over time.

[0042] Next, with reference to Figures 6A and 6B, the time transition of the magnetic field strength measured by the magnetic sensor 161 when the rotary joint 10 is in an abnormal state will be explained. Figure 6A is a graph showing the transition of the magnetic field strength when the rotary joint 10 shown in Figure 2 is in an abnormal state instantaneously. Figure 6B is a graph showing the transition of the magnetic field strength when the rotary joint 10 shown in Figure 2 is in an abnormal state gradually. In Figures 6A and 6B, the predetermined range used by the determination unit 230 for determination is a range in which the lower limit is the first threshold b1 and the upper limit is not defined.

[0043] In Figure 6A, the magnetic field strength value measured by the magnetic sensor 161 falls below the first threshold b1, which is the lower limit of a predetermined range, at time t1. Similarly, in Figure 6B, the magnetic field strength value measured by the magnetic sensor 161 falls below the first threshold b1, which is the lower limit of a predetermined range, at time t2. As shown in Figures 6A and 6B, the magnetic field strength value measured by the magnetic sensor 161 changes more rapidly when the rotary coupling 10 becomes abnormal instantaneously than when it becomes abnormal gradually, resulting in a larger change per unit time and a larger absolute value of the slope of the magnetic field strength graph. The unit time is a reference time for defining the degree of change in magnetic field strength, and can be any time as long as it is on a scale that allows the control device 20 to determine the amount of change in magnetic field strength.

[0044] Returning to Figure 4, the operation control unit 240 controls the operation of the rotary joint 10 based on the determination of the determination unit 230. Specifically, if the determination unit 230 determines that the rate of change per unit time of the measured value of the rotary joint 10 is greater than or equal to the second threshold, the operation control unit 240 controls the operation of the rotary joint 10 to transition the state of the rotary joint 10 to a stable state and then stop the operation of the rotary joint 10. The stable state is one of the operating states of the rotary joint 10, in which the rotary joint 10 maintains a predetermined posture or operates slightly at a speed less than or equal to a predetermined speed. Also, in the stable state, each signal of the rotary joint 10 is maintained in a predetermined state or changes slightly. If the determination unit 230 determines that the rate of change per unit time of the measured value is less than the second threshold, the operation control unit 240 controls the operation of the rotary joint 10 to continue the operation of the rotary joint 10.

[0045] The functional configuration of the control device 20 has been described above. Next, the sequence of processes of the control system 1 will be described in detail. Figure 7 is a flowchart showing an example of the process flow of the control system 1 shown in Figure 1. Note that the content and order of the following steps can be changed as appropriate.

[0046] (Step SP10) The control system 1 acquires the measurement results measured by the measuring unit 16 from the rotary coupling 10 using the acquisition unit 220. The control system 1 stores the measured values ​​from the acquired measurement results in the measurement data 211 of the storage unit 210 using the acquisition unit 220. The control system 1 either acquires the measurement results each time at regular intervals or continuously acquires the measurement results. Then, the process moves on to the process in step SP12.

[0047] (Step SP12) The control system 1 uses the determination unit 230 to refer to the measurement data 211 stored in the storage unit 210. The control system 1 uses the determination unit 230 to determine whether the measured value indicated by the measurement data 211 is outside a predetermined range. If the determination is positive, the process proceeds to step SP14. If the determination is negative, the control system 1 performs the measurement data acquisition again in step SP10 after the determination.

[0048] (Step SP14) The control system 1 uses the determination unit 230 to determine whether the rate of change per unit time of the measured value indicated by the measurement data 211 is greater than or equal to the second threshold. If the determination is positive, the process proceeds to step SP16. If the determination is negative, the process proceeds to step SP22.

[0049] (Step SP16) The control system 1, via the determination unit 230, notifies the operator of the control system 1 that the state of the rotary coupling 10 has instantly become abnormal. Then, the process proceeds to step SP18.

[0050] (Step SP18) The control system 1, via the motion control unit 240, transitions the operating state of the rotary coupling 10 to a stable state. Then, the process proceeds to the process of step SP20.

[0051] (Step SP20) The control system 1 stops the operation of the rotary joint 10 via the operation control unit 240. Specifically, the control system 1 stops the operation of the rotary joint 10 via the operation control unit 240, for example, when a predetermined time has elapsed since the rotary joint 10 transitioned to a stable operating state. Then, the series of processes shown in Figure 7 is completed.

[0052] (Step SP22) The control system 1, via the determination unit 230, notifies the operator of the control system 1 that the state of the rotary coupling 10 has gradually become abnormal. Then, the series of processes shown in Figure 7 is completed.

[0053] <Effects> In this embodiment, the control device 20 controls the operation of a rotary joint 10 to which an angle sensor (magnetic sensor 161) capable of measuring the rotation angle by magnetic detection is attached. The control device 20 also includes a determination unit 230 that determines the state of the rotary joint 10 based on the rate of change of the magnetic measurement value per unit time when the magnetic measurement value measured by magnetic detection is outside a predetermined range. The control device 20 also includes an operation control unit 240 that controls the operation of the rotary joint 10 based on the determination of the determination unit 230. Therefore, the control device 20 can continue the operation of the rotary joint 10 without stopping its operation in response to an abnormal state of the rotary joint 10.

[0054] Furthermore, in this embodiment, the determination unit 230 determines that the state of the rotary joint 10 has instantaneously become abnormal if the rate of change per unit time of the measured magnetic value is greater than or equal to the second threshold. Also, the determination unit 230 determines that the state of the rotary joint 10 has gradually become abnormal if the rate of change per unit time of the measured magnetic value is less than the second threshold. Therefore, the control device 20 determines whether the rotary joint 10 has instantaneously become abnormal or gradually, and can continue operating the rotary joint 10 without stopping its operation if the abnormal state of the rotary joint 10 is a gradual change.

[0055] Furthermore, in this embodiment, the determination unit 230 notifies the operator of the control device 20 of the determination result regarding the rotary joint 10. Therefore, the control device 20 makes it easier for the operator to determine the urgency of the repair of the rotary joint 10.

[0056] Furthermore, in this embodiment, the operation control unit 240 controls the operation of the rotary joint 10 so as to transition the state of the rotary joint 10 to a stable state and then stop its operation when the determination unit 230 determines that the amount of change per unit time of the measured value related to magnetism is equal to or greater than the second threshold.Therefore, the control device 20 can stop the operation of the rotary joint 10 while suppressing damage caused by the sudden stopping of the rotary joint 10 when the rotary joint 10 instantaneously enters an abnormal state.

[0057] Furthermore, in this embodiment, the rotary coupling 10 includes a magnet 15 and a magnetic angle sensor (magnetic sensor 161) that detects the magnetic flux generated by the magnet 15 and measures the magnetic field strength and rotation angle. The measured value related to magnetism is the magnetic field strength measured by the angle sensor. Therefore, the control device 20 can continue operation when the rotary coupling 10 gradually enters an abnormal state, thereby suppressing the increase in costs caused by stopping and restarting the device.

[0058] <Variation> It should be noted that the present invention is not limited to the embodiments described above. That is, any design modifications made to the above embodiments by those skilled in the art are also included within the scope of the present invention, as long as they retain the features of the present invention. Furthermore, the elements of the above embodiments and the modifications described later can be combined to the extent that it is technically possible, and any combination thereof is also included within the scope of the present invention, as long as it retains the features of the present invention.

[0059] For example, in this embodiment, the determination unit 230 may determine the state of the rotary joint 10 based on whether the rate of change of the measured magnetic field strength per unit time is greater than or equal to a second threshold, regardless of whether the measured magnetic field strength is outside a predetermined range. With this configuration, even if the measured magnetic field strength is within a predetermined range but the magnetic field strength changes rapidly, causing the rotary joint 10 to instantly enter an abnormal state, the control device 20 can continue operating the rotary joint 10 without stopping its operation in response to the abnormal state.

[0060] Furthermore, the case 162 may be provided with a guide portion on its inner circumference that guides the magnetic sensor 161 parallel to the first direction in response to pressure from the first direction. Here, the guide portion may be a pair of plate-shaped members connected at opposing positions on the inner circumference of the case 162. The magnetic sensor 161 may also be provided with a pair of grooves on its outer circumference that run along the pair of guide portions. With this configuration, in the case 162 of the rotary joint 10 is damaged when the measuring portion 16 is pressed from the first direction by oil flowing through the hole 132, the magnetic sensor 161 moves parallel to the first direction by the guide portion. Therefore, since the variation in the distance between each point on the measuring surface of the magnetic sensor 161 and the magnet 15 is suppressed, abnormal operation can be suppressed when an abnormal condition occurs instantaneously and the rotation angle changes rapidly.

[0061] Furthermore, in this embodiment, the control system 1 does not limit itself to the determination unit 230 of the control device 20 determining the state of the rotary joint 10. The control system 1 may also determine the state of the rotary joint 10 using the magnetic sensor 161 in the measurement unit 16. Specifically, the control system 1 may determine whether the rate of change of the magnetic field strength per unit time is greater than or equal to a second threshold when the magnetic field strength is outside a predetermined range. The control system 1 may also determine that the state of the rotary joint 10 has instantaneously become abnormal when the determination by the magnetic sensor 161 is affirmative. The control system 1 may also determine that the state of the rotary joint 10 has gradually become abnormal when the determination is negative. In addition, the control system 1 may control the operation of the rotary joint 10 according to the determination result of the magnetic sensor 161 using the operation control unit 240 of the control device 20.

[0062] With this configuration, even when the control system 1 uses the magnetic sensor 161 to perform a determination process and the control device 20 controls the operation of the rotary coupling 10 according to the determination result of the magnetic sensor 161, the operation of the rotary coupling 10 can continue without stopping, depending on the abnormal state of the rotary coupling 10. [Explanation of Symbols]

[0063] 1...Control system, 10...Rotary coupling, 12...Rotor, 13...Shaft, 20...Control device, 230...Determination unit, 240...Motion control unit

Claims

1. A control device for controlling the operation of a rotary coupling to which a magnetic sensor capable of measuring the rotation angle by magnetic detection is attached, A determination unit that determines the state of the rotary coupling based on the rate of change per unit time of the measured magnetic value when the measured magnetic value is outside a predetermined range, An operation control unit controls the operation of the rotary coupling based on the determination of the determination unit, A control device equipped with the following features.

2. The control device according to claim 1, wherein the determination unit determines that the state of the rotary joint has instantaneously become abnormal if the amount of change per unit time of the measured value of the magnetism is greater than or equal to a threshold, and determines that the state of the rotary joint has gradually become abnormal if the amount of change per unit time of the measured value of the magnetism is less than the threshold.

3. The control device according to claim 2, wherein the operation control unit controls the operation of the rotary joint so as to stop the operation of the rotary joint after transitioning the state of the rotary joint to a predetermined stable state when the determination unit determines that the amount of change per unit time of the measured value of the magnetism is greater than or equal to the threshold.

4. The rotary joint comprises a magnet and a magnetic angle sensor that detects the magnetic flux generated by the magnet and measures the magnetic field strength and the rotation angle. The control device according to any one of claims 1 to 3, wherein the measured value relating to the magnetism is the magnetic field strength measured by the angle sensor.

5. A rotary coupling comprising a rotor, a shaft rotatably connected to the rotor with the central axis of rotation as the axis of rotation, and a measuring unit that measures the rotation angle between the rotor and the shaft with respect to the central axis of rotation by magnetic detection, A control device having a determination unit that determines the state of the rotary joint based on the rate of change per unit time of the measured magnetic value when the measured magnetic value measured by the measurement unit is outside a predetermined range, and an operation control unit that controls the operation of the rotary joint based on the determination of the determination unit, A control system equipped with the following features.

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