Control device, control system, multi-axis testing machine, control method, and control program

Abstract

We provide a multi-axis testing machine that operates even when communication is interrupted. [Solution] The second control device 200 generates a clock signal, generates a sampling clock signal based on the clock signal, receives a reference signal transmitted from the first control device 100, and adjusts the period of the sampling clock signal based on the reference signal.

Description

[[Technical Field]]

[0001] The present invention relates to a control device, a control system, a multi-axis testing machine, a control method, and a control program. [[Background Art]]

[0002] Patent Document 1 discloses a multi-axis testing machine. The multi-axis testing machine disclosed in Patent Document 1 includes a plurality of actuators, each actuator is equipped with a control unit, one of the plurality of control units is used as a master unit, and the other control units are used as slave units. The slave unit generates a sampling clock signal based on a clock signal generated by the master unit. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2000-209091 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] In the multi-axis testing machine as described in Patent Document 1, a slave unit whose communication with the master unit is interrupted cannot generate a sampling clock signal and thus cannot operate.

[0005] An object of the present invention is to provide a multi-axis testing machine that can operate even when communication is interrupted. [[Means for Solving the Problem]]

[0006] To solve the above problems, a control device according to one embodiment of the present invention is a second control device comprising: a clock generation unit that generates a clock signal; a sampling clock generation unit that generates a sampling clock signal based on the clock signal; a signal receiving unit that receives a reference signal transmitted from the first control device; and a sampling period adjustment unit that adjusts the period of the sampling clock signal generated by the sampling clock generation unit based on the reference signal.

[0007] The sampling period adjustment unit may measure the period of the reference signal, detect the phase difference between the sampling clock signal and the reference signal, and if no phase difference exists, set the period of the reference signal to the period of the sampling clock signal, or if a phase difference exists, adjust the period of the sampling clock signal so that the phase difference becomes smaller.

[0008] The sampling period adjustment unit may, if the sampling clock signal is High at the rising edge timing of the reference signal, make the period of the sampling clock signal longer than the period of the reference signal, and if the sampling clock signal is Low at the rising edge timing of the reference signal, make the period of the sampling clock signal shorter than the period of the reference signal.

[0009] The sampling period adjustment unit may, if the sampling clock signal is High at the rising edge timing of the reference signal, lengthen the period of the sampling clock signal by a first count to make it longer than the period of the reference signal, and if the sampling clock signal is Low at the rising edge timing of the reference signal, shorten the period of the sampling clock signal by a second count to make it shorter than the period of the reference signal.

[0010] The sampling period adjustment unit may also set the sampling clock signal period to the period of the last measured reference signal if the time during which the reference signal is not received by the signal receiving unit exceeds a predetermined time.

[0011] The device further includes a storage unit for storing the initial sampling period, and the sampling period adjustment unit may set the initial sampling period to the period of the sampling clock signal after the power supply of the second control device is turned on and until the period of the reference signal is measured.

[0012] A control system according to one embodiment of the present invention comprises the first control device and the second control device.

[0013] A multi-axis testing machine according to one embodiment of the present invention has the control system described above.

[0014] A control method according to one embodiment of the present invention is a control method performed by a second control device, comprising: a clock generation step of generating a clock signal; a sampling clock generation step of generating a sampling clock signal based on the clock signal; a signal reception step of receiving a reference signal transmitted from a first control device; and a sampling period adjustment step of adjusting the period of the sampling clock signal generated by the sampling clock generation step based on the reference signal.

[0015] A control program according to one embodiment of the present invention causes a computer to execute the control method. [Effects of the Invention]

[0016] This invention makes it possible to provide a multi-axis testing machine that operates even when communication is interrupted. [Brief explanation of the drawing]

[0017] [Figure 1] This figure shows a multi-axis testing machine according to one embodiment of the present invention. [Figure 2] It is a diagram illustrating an example of a signal flow in a control system. [Figure 3] It is a diagram showing an example of a first control device 100. [Figure 4] It is a diagram showing an example of a second control device 200. [Figure 5] It is a diagram illustrating the relationship between a sampling clock signal of a first control device 100 and a reference signal. [Figure 6] It is a diagram illustrating adjustment of a sampling clock signal of a second control device 200. [Figure 7] It is a diagram illustrating adjustment of a sampling clock signal of a second control device 200. [Figure 8] It is a diagram showing an example of processing operations in a second control device 200. MODE FOR CARRYING OUT THE INVENTION

[0018] <Multi-axis testing machine> FIG. 1 is a diagram showing a multi-axis testing machine according to an embodiment of the present invention. The multi-axis testing machine according to the present embodiment tests, for example, the durability of a component against loads in two or more axial directions. Therefore, as shown in FIG. 1, the multi-axis testing machine according to the present embodiment includes two or more actuators, and each of the two or more actuators applies a load in one axial direction to a component, for example. In the example shown in FIG. 1, the multi-axis testing machine includes three actuators (actuator A1, actuator A2, actuator A3), but the number of actuators included in the multi-axis testing machine according to the present embodiment may be two, or may be four or more. The axial load applied by each actuator is one-way or bidirectional compression and tension, vibration excitation, axial rotational torsion, or the like. Examples of multi-axis testing machines capable of applying such loads include, but are not limited to, compression testing machines, tensile testing machines, vibration testing machines, torsion testing machines, and the like.

[0019] The multi-axis testing machine according to the present embodiment includes two or more control devices that are in one-to-one correspondence with two or more actuators, and each of the two or more control devices controls the corresponding actuator. The two or more control devices constitute a control system that controls the corresponding two or more actuators. Each of the two or more control devices includes, for example, a computer (e.g., an MPU (Micro Processor Unit)).

[0020] In order to synchronize the control of two or more actuators, the control system according to the present embodiment includes, as shown in FIG. 1, one first control device 100 and one or more second control devices 200 serving as the two or more control devices. In the example shown in FIG. 1, the control system includes one first control device 100 and two second control devices 200 (a second control device 200A and a second control device 200B). The first control device 100 corresponds to an actuator A1 and controls the actuator A1; the second control device 200A corresponds to an actuator A2 and controls the actuator A2; and the second control device 200B corresponds to an actuator A3 and controls the actuator A3.

[0021] The multi-axis testing machine according to this embodiment has two or more sets of actuators and control devices, and two or more sensors that correspond one-to-one with each other. Each of the two or more sensors measures a physical quantity (e.g., displacement or load) related to the corresponding actuator and inputs the measured value of the physical quantity to the corresponding control device. In the multi-axis testing machine according to this embodiment, each of the two or more control devices provides feedback control to the corresponding actuator based on the physical quantity measured by the corresponding sensor (i.e., the sensor that measures the physical quantity related to the corresponding actuator). In the example shown in Figure 1, sensor S1 corresponds to actuator A1 and the first control device 100, measures a physical quantity related to actuator A1, and inputs the measured value of the physical quantity to the first control device 100. Sensor S2 corresponds to actuator A2 and the second control device 200A, measures a physical quantity related to actuator A2, and inputs the measured value of the physical quantity to the second control device 200A. Sensor S3 corresponds to actuator A3 and the second control device 200B, measures a physical quantity related to actuator A3, and inputs the measured value of the physical quantity to the second control device 200B. In the example shown in Figure 1, the first control device 100 performs feedback control of actuator A1 based on a physical quantity measured by sensor S1, the second control device 200A performs feedback control of actuator A2 based on a physical quantity measured by sensor S2, and the second control device 200B performs feedback control of actuator A3 based on a physical quantity measured by sensor S3.

[0022] As shown in Figure 1, the control system according to this embodiment has a synchronous communication line SL, and the first control device 100 and one or more second control devices 200 are connected to this synchronous communication line SL by communication lines. In other words, in this embodiment, the first control device 100 and one or more second control devices 200 are connected via this synchronous communication line SL. In the control system according to this embodiment, for example, the first control device 100 and one or more second control devices 200 are configured to perform half-duplex communication via the synchronous communication line SL, and the first control device 100 and one or more second control devices 200 perform multi-bit asynchronous serial communication via the synchronous communication line SL.

[0023] As shown in Figure 2, each of the first control device 100 and one or more second control devices 200 can transmit signals to other control devices by transmitting signals to the synchronous communication line SL, and each of the first control device 100 and one or more second control devices 200 can receive signals transmitted to the synchronous communication line SL by other control devices. In the example shown in Figure 2, the signal transmitted from the first control device 100 to the synchronous communication line SL is received by the second control devices 200A and 200B from the synchronous communication line SL.

[0024] The control system according to this embodiment is, for example, a so-called master-slave system, where the first control device 100 is the master and the second control device 200 is the slave. When the control system according to this embodiment is a master-slave system, only the first control device 100 actively transmits signals to the synchronous communication line SL, and the second control device 200 does not actively transmit signals to the synchronous communication line SL, but transmits a signal corresponding to the request to the synchronous communication line SL when the first control device 100 sends a signal requesting a reply.

[0025] <Control System> Figure 3 shows an example of the first control device 100, and Figure 4 shows an example of the second control device 200. The first control device 100 has a clock generation unit 110 and a sampling clock generation unit 120, and each of the one or more second control devices 200 has a clock generation unit 210 and a sampling clock generation unit 220.

[0026] The clock generation unit 110 of the first control device 100 and the clock generation unit 210 of the second control device 200 generate a clock signal.

[0027] The sampling clock generation unit 120 of the first control device 100 generates a sampling clock signal based on the clock signal generated by the clock generation unit 110. Based on the sampling clock signal generated by the sampling clock generation unit 120, the first control device 100 samples the measurement value from the corresponding sensor (sensor S1 in the example shown in Figure 1) and inputs a control signal to the corresponding actuator (actuator A1 in the example shown in Figure 1).

[0028] The sampling clock generation unit 220 of the second control device 200 generates a sampling clock signal based on the clock signal generated by the clock generation unit 210. Based on the sampling clock signal generated by the sampling clock generation unit 220, the second control device 200 samples the measured values ​​from the corresponding sensors (sensors S2 and S3 in the example shown in Figure 1) and inputs control signals to the corresponding actuators (actuators A2 and A3 in the example shown in Figure 1).

[0029] Thus, in this embodiment, each of the control devices (the first control device 100 and one or more second control devices 200) generates a clock signal and generates a sampling clock signal based on that clock signal. Therefore, even if communication with the first control device 100 is interrupted, the second control device 200 can operate using the sampling clock signal it has generated. Thus, the multi-axis testing machine according to this embodiment can continue to operate even when communication is interrupted.

[0030] <Adjustment of the sampling period of the second control device 200> Due to an error between the clock signal generated by the clock generation unit 110 of the first control device 100 and the clock signal generated by the clock generation unit 210 of the second control device 200, there are times when the sampling clock signal of the first control device 100 (i.e., the sampling clock signal generated by the sampling clock generation unit 120) and the sampling clock signal of the second control device 200 (i.e., the sampling clock signal generated by the sampling clock generation unit 220) are out of sync.

[0031] Therefore, the first control device 100 further includes a signal transmission unit 130, and the second control device 200 further includes a signal receiving unit 230 and a sampling period adjustment unit 240.

[0032] The signal transmission unit 130 of the first control device 100 transmits a reference signal to the synchronous communication line SL at the period of the sampling clock signal generated by the sampling clock generation unit 120 (the sampling period of the first control device 100). The reference signal transmitted by the signal transmission unit 130 is a signal to inform the second control device 200 of the sampling period of the first control device 100, and as shown in Figure 5, the rising edge of the reference signal coincides with the rising edge of the sampling clock signal of the first control device 100 (the sampling clock signal generated by the sampling clock generation unit 120).

[0033] The signal receiving unit 230 of the second control device 200 receives the reference signal transmitted from the first control device 100 from the synchronous communication line SL.

[0034] The sampling period adjustment unit 240 of the second control device 200 adjusts the period of the sampling clock signal generated by the sampling clock generation unit 220 (the sampling period of the second control device 200) based on the reference signal transmitted from the first control device 100.

[0035] At this time, the sampling period adjustment unit 240 measures the count number CS (period of the reference signal) between the rising edges of two consecutive reference signals, based on the clock signal generated by the clock generation unit 210 of the second control device 200. As described above, the reference signal is a signal transmitted from the first control device 100 at the sampling period of the first control device 100. Therefore, the count number CS (period of the reference signal) between the rising edges of these two consecutive reference signals corresponds to the sampling period of the first control device 100.

[0036] The sampling period adjustment unit 240 then detects the phase difference between the sampling clock signal (the sampling clock signal of the second control device 200) generated by the sampling clock generation unit 220 and the reference signal (i.e., the difference between the rising edge timing of the sampling clock signal and the rising edge timing of the reference signal). If there is no phase difference between the sampling clock signal generated by the sampling clock generation unit 220 and the reference signal (i.e., if the rising edge timing of the sampling clock signal generated by the sampling clock generation unit 120 and the rising edge timing of the reference signal are not out of sync and are in agreement), the measured count CS (period of the reference signal) is set as the sampling period of the second control device 200.

[0037] On the other hand, if there is a phase difference between the sampling clock signal generated by the sampling clock generation unit 220 and the reference signal (that is, if the rising edge timing of the sampling clock signal generated by the sampling clock generation unit 220 and the rising edge timing of the reference signal are out of sync and do not match), the period of the sampling clock signal generated by the sampling clock generation unit 220 (the sampling period of the second control device 200) is adjusted so that the phase difference becomes smaller (that is, so that the rising edge timing of the sampling clock signal generated by the sampling clock generation unit 220 approaches the rising edge timing of the reference signal).

[0038] Therefore, in this embodiment, it is possible to synchronize the sampling clock signal of the first control device 100 with the sampling clock signal of the second control device 200. Furthermore, in this embodiment, if communication between the first control device 100 and the second control device 200 is interrupted and the sampling clock signals of the first control device 100 and the second control device 200 become significantly out of sync, it is possible to gradually synchronize the sampling clock signal of the first control device 100 and the sampling clock signal of the second control device 200 after communication between the first control device 100 and the second control device 200 is restored.

[0039] The sampling clock signal of the second control device 200 is out of sync with the sampling clock signal of the first control device 100, and at the timing of the rising edge of the reference signal transmitted from the first control device 100, the sampling clock signal generated by the sampling clock generation unit 220 (the sampling clock signal of the second control device 200) may be high, as shown in Figure 6.

[0040] In this embodiment, if the sampling clock signal of the second control device 200 is High at the rising edge timing of the reference signal, the sampling period adjustment unit 240 makes the period (sampling period) of the sampling clock signal generated by the sampling clock generation unit 220 longer than the period of the reference signal (count CS between the rising edges of two adjacent reference signals), as shown in Figure 6. For example, if the sampling clock signal of the second control device 200 is High at the rising edge timing of the reference signal, the sampling period adjustment unit 240 makes the period of the sampling clock signal generated by the sampling clock generation unit 220 (sampling period of the second control device 200) longer than the period of the reference signal (count CS) by the first count C1 (for example, C1=1) of the clock generated by the clock generation unit 210 of the second control device 200. In other words, as shown in Figure 6, the sampling period adjustment unit 240 sets the sampling period of the second control device 200 to a count CA1 (=CS+C1), which is the count CS (period of the reference signal) plus the first count C1.

[0041] Furthermore, at the rising edge timing of the reference signal transmitted from the first control device 100, the sampling clock signal generated by the sampling clock generation unit 220 may be Low, as shown in Figure 7.

[0042] In this embodiment, if the sampling clock signal of the second control device 200 is Low at the rising edge timing of the reference signal, the sampling period adjustment unit 240 shortens the period of the sampling clock signal generated by the sampling clock generation unit 220 (the sampling period of the second control device 200) to the period of the reference signal (the number of counts CS between the rising edges of two adjacent reference signals), as shown in Figure 7. For example, if the sampling clock signal of the second control device 200 is Low at the rising edge timing of the reference signal, the sampling period adjustment unit 240 shortens the period of the sampling clock signal generated by the sampling clock generation unit 220 (the sampling period of the second control device 200) to the period of the reference signal (count CS) by the second count C2 (for example, C2=1) of the clock generated by the clock generation unit 210 of the second control device 200. In other words, as shown in Figure 7, the sampling period adjustment unit 240 sets the sampling period of the second control device 200 to the count number CA2 (=CS-C2), which is obtained by subtracting the second count number C2 from the count number CS (period of the reference signal). Here, the second count number may be the same as the first count number, or it may be different.

[0043] The sampling adjustment unit 240 is configured to adjust the sampling period of the second control device 200, for example, each time the rising edge of the reference signal occurs. By doing so, the phase difference gradually decreases, and it becomes possible to converge the phase difference to zero. As a result, it becomes possible to gradually synchronize the sampling clock signal of the first control device 100 and the sampling clock signal of the second control device 200.

[0044] The sampling adjustment unit 240 may measure the above count CS each time a rising edge occurs in the reference signal. In other words, the sampling adjustment unit 240 may measure the count CS between the two most recent consecutive rising edges of the reference signal each time a rising edge occurs in the reference signal, and use this count CS to adjust the sampling period of the second control device 200. Alternatively, the sampling adjustment unit 240 may measure the above count CS only when the first two consecutive rising edges of the reference signal occur.

[0045] Temporary communication failures or disconnections may occur, preventing the second control device 200 from receiving the reference signal. In such cases, the second control device 200 should use the count CS measured when it last received the reference signal as its sampling period. In other words, if the time during which the signal receiving unit 230 has not received the reference signal exceeds a predetermined time, the sampling period adjustment unit 240 should use the period of the last measured reference signal (i.e., the count CS between the rising edges of two consecutive reference signals measured when the last reference signal was received) as the sampling period of the second control device 200 (the period of the sampling clock signal generated by the sampling clock generation unit 220).

[0046] When the power to the second control device 200 is started up, the second control device 200 has not yet received a reference signal, and the sampling period adjustment unit 240 cannot adjust the sampling clock period (sampling period of the second control device 200) generated by the sampling clock generation unit 220 based on the period of the reference signal (count number CS). Therefore, it is preferable for the second control device 200 to further include a storage unit 250. The storage unit 250 is configured to store the initial sampling period, and the sampling period adjustment unit 240 is configured to use the initial sampling period stored in the storage unit 250 as the sampling clock period (sampling period of the second control device 200) generated by the sampling clock generation unit 220 until the period of the reference signal is measured after the power to the second control device 200 is started up (i.e., until two consecutive reference signals are received and the period of the reference signal can be measured). The initial sampling period stored in the storage unit 250 may be a predetermined count number, or it may be the period of the reference signal last measured during the previous operation.

[0047] <Processing operation in the second control device 200> Figure 8 shows an example of processing operation in the second control device 200. The processing operation shown in Figure 8 is performed, for example, each time a rising edge occurs in the reference signal received by the signal receiving unit 230 of the second control device 200.

[0048] The sampling period adjustment unit 240 measures the count CS (period of the reference signal) between the rising edges of two consecutive reference signals that occurred most recently, and detects the phase difference between the sampling clock signal generated by the sampling clock generation unit 220 and the reference signal (step S801).

[0049] If no phase difference exists (step S802, YES), the sampling period adjustment unit 240 sets the count number CS (period of the reference signal) to the period of the sampling clock generated by the sampling clock generation unit 220 (sampling period of the second control device 200) (step S803).

[0050] If a phase difference exists and the sampling clock signal is High at the rising edge timing of the received reference signal (step S802, NO; step S804, YES), the sampling period adjustment unit 240 sets the count CA1 (=CS+C1), obtained by adding the first count C1 to the count CS, as the period of the sampling clock generated by the sampling clock generation unit 220 (the sampling period of the second control device 200) (step S805).

[0051] If a phase difference exists and the sampling clock signal is Low at the rising edge timing of the received reference signal (step S802, NO; step S804, NO), the sampling period adjustment unit 240 subtracts the second count C2 from the count CS to obtain a count CA2 (=CS-C2), which is then set as the period of the sampling clock generated by the sampling clock generation unit 220 (the sampling period of the second control device 200) (step S806).

[0052] The present invention has been described above with reference to preferred embodiments. While the present invention has been described with specific examples, various modifications and changes can be made to these examples without departing from the spirit and scope of the invention as described in the claims. [Explanation of Symbols]

[0053] 100 First control device 110 Clock generation unit 120 Sampling Clock Generation Unit 130 Signal transmission unit 200 Second control device 210 Clock generation unit 220 Sampling Clock Generation Unit 230 Signal receiving unit 240 Sampling Period Adjustment Section 250 Storage section

Claims

1. A clock generation unit that generates a clock signal, A sampling clock generation unit generates a sampling clock signal based on the aforementioned clock signal, A signal receiving unit that receives a reference signal transmitted from the first control device, A second control device comprising: a sampling period adjustment unit that adjusts the period of the sampling clock signal generated by the sampling clock generation unit based on the reference signal; and a second control device.

2. The sampling period adjustment unit is, The period of the aforementioned reference signal is measured, The phase difference between the sampling clock signal and the reference signal is detected. If the aforementioned phase difference does not exist, the period of the reference signal is set to the period of the sampling clock signal. The second control device according to claim 1, wherein if the aforementioned phase difference exists, the period of the sampling clock signal is adjusted so that the aforementioned phase difference becomes smaller.

3. The sampling period adjustment unit is, If the sampling clock signal is High at the rising edge timing of the reference signal, the period of the sampling clock signal is made longer than the period of the reference signal. The second control device according to claim 2, wherein if the sampling clock signal is Low at the timing of the rising edge of the reference signal, the period of the sampling clock signal is made shorter than the period of the reference signal.

4. The sampling period adjustment unit is, If the sampling clock signal is High at the rising edge timing of the reference signal, the period of the sampling clock signal is made longer than the period of the reference signal by a first count. The second control device according to claim 3, wherein if the sampling clock signal is Low at the rising edge timing of the reference signal, the period of the sampling clock signal is shortened by a second number of counts compared to the period of the reference signal.

5. The sampling period adjustment unit is, The second control device according to any one of claims 2 to 4, wherein if the time during which the reference signal is not received by the signal receiving unit exceeds a predetermined time, the period of the last measured reference signal is set to be the period of the sampling clock signal.

6. It further has a memory unit that stores the initial sampling period, The sampling period adjustment unit is, The second control device according to any one of claims 2 to 4, wherein the initial sampling period is set to the period of the sampling clock signal after the power supply of the second control device is turned on, until the period of the reference signal is measured.

7. The first control device described above, A control system comprising a second control device according to any one of claims 2 to 4.

8. A multi-axis testing machine having the control system described in claim 7.

9. A control method performed by a second control device, The clock generation process generates a clock signal, A sampling clock generation step that generates a sampling clock signal based on the aforementioned clock signal, A signal receiving step of receiving a reference signal transmitted from the first control device, A control method comprising: a sampling period adjustment step, which adjusts the period of the sampling clock signal generated by the sampling clock generation step based on the reference signal.

10. A control program that causes a computer to execute the control method described in claim 9.

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