Control device
The control device corrects command values using measured oscillation frequencies to achieve precise control of controlled objects at low cost, addressing the limitations of voltage-controlled oscillators in existing systems.
Patent Information
- Application Number
- JP2024016188
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-02-06
- Publication Date
- 2025-08-19
AI Technical Summary
Existing control devices face challenges in achieving high control precision of controlled objects at low cost, particularly in systems using voltage-controlled oscillators, which require external adjustment circuits and are not integrated into standard integrated circuits, leading to increased costs.
A control device that communicates with a command device using a synchronization signal and includes a specified value storage unit, a clock signal generation unit, a measurement value acquisition unit, a correction value calculation unit, a command value acquisition unit, and a control unit to calculate and apply a correction value for command values, enabling precise control without the need for highly accurate oscillators.
The control device achieves high precision control of the controlled object in real time, even with temperature changes, by correcting command values based on measured oscillation frequencies, thus reducing the need for expensive high-precision oscillators.
Smart Images
Figure 2025121030000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a control device that communicates with a command device based on a synchronization signal generated by the command device and controls the driving of a controlled object. [Background technology]
[0002] Conventionally, control devices have been used that communicate with, for example, a higher-level system to obtain control commands and then control the operation of a controlled object based on the obtained control commands. One example of such communication with a higher-level system is master-slave communication. In master-slave communication, independent clock signals are used. If the oscillation frequencies of these clock signals differ between the master transceiver and the slave transceiver, the control commands may not be transmitted properly. Therefore, a crystal or ceramic oscillator is installed in each of the master transceiver and the slave transceiver to minimize the difference in the oscillation frequencies of the clock signals between the two. Such crystal or ceramic oscillators have high oscillation frequency accuracy and little temperature dependency, thereby achieving high communication quality. However, crystal or ceramic oscillators are more expensive than, for example, an LC oscillator circuit configured using a coil and a capacitor or an RC oscillator circuit configured using a resistor and a capacitor, resulting in a problem of increased overall system costs.
[0003] Therefore, in the data communication system described in Patent Document 1, only the master device is equipped with a crystal oscillator, and the slave devices are configured with a voltage-controlled oscillator (VCO) consisting of an RC oscillator circuit or an LC oscillator circuit using a variable capacitance diode. The slave device adjusts the oscillation frequency of the clock signal generated by the voltage-controlled oscillator based on the signal received from the master device. This allows the slave devices to be configured inexpensively. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-303632 Summary of the Invention [Problem to be solved by the invention]
[0005] In the data communication system described in Patent Document 1, the oscillation frequency of the clock signal generated by the voltage-controlled oscillator of the slave device is adjusted based on the signal received from the master device. Therefore, the voltage-controlled oscillator must be configured so that its oscillation frequency can be externally adjusted. Adding an adjustment circuit to adjust the oscillation frequency increases costs. Furthermore, inexpensive LC and RC oscillator circuits are generally built into integrated circuits. Existing integrated circuits are not configured to allow external adjustment, requiring a new design or the addition of a separate crystal oscillator. Furthermore, functions supported by communication standards such as LIN (Local Interconnect Network) communication can sometimes ensure communication quality for the slave device without using a high-precision clock signal generation circuit. In such a system, for the slave device, improving the precision of the clock signal oscillation frequency is important in order to improve the control precision of the controlled object. Therefore, the data communication system described in Patent Document 1 leaves room for improvement in terms of inexpensively improving the control precision of the controlled object.
[0006] Therefore, there is a demand for a control device that can improve the control accuracy of a controlled object at low cost. [Means for solving the problem]
[0007] A characteristic configuration of a control device according to the present invention is a control device that communicates with a command device based on a synchronization signal generated by the command device and controls drive of a controlled object, and includes: a specified value information storage unit that stores a specified value that specifies the oscillation frequency of the synchronization signal generated in the command device as specified value information; a clock signal generation unit that generates a clock signal of a predetermined oscillation frequency; a measurement value information acquisition unit that acquires, based on the clock signal, a measurement value obtained by measuring the oscillation frequency of the synchronization signal transmitted from the command device as measurement value information; a correction value calculation unit that calculates a correction value for correcting the command value information transmitted from the command device based on the specified value information and the measurement value information; a command value information acquisition unit that acquires command value information indicating a command value for the controlled object from the command device; a corrected command value calculation unit that calculates a corrected command value obtained by correcting a period of the command value information based on the correction value; and a control unit that controls drive of the controlled object based on the corrected command value.
[0008] With this characteristic configuration, a correction value for correcting the command value information is calculated based on a specified value that specifies the oscillation frequency of the synchronization signal generated in the master device based on the specified value information stored in the specified value information storage unit and a measured value of the oscillation frequency of the synchronization signal of the master device measured by the control device, acquired by the measurement value information acquisition unit, and the calculated correction value is used to correct the command value for the control target transmitted from the master device. This eliminates the need for a highly accurate oscillation frequency on the control device side, as the control target is controlled based on the corrected command value calculated by correcting the command value, thereby enabling highly accurate control of the control target in accordance with the command value. Furthermore, since such correction of the command value can be performed appropriately and at a desired timing, the control target can be controlled in real time with high accuracy, even if, for example, the environmental temperature of the control device changes. [Brief explanation of the drawings]
[0009] [Figure 1] FIG. 2 is a block diagram showing the configuration of a control device and a master device. [Figure 2]FIG. 10 is an explanatory diagram of calculation of a correction value. [Figure 3] FIG. 10 is an explanatory diagram of calculation of a corrected command value. DETAILED DESCRIPTION OF THE INVENTION
[0010] The control device according to the present invention is configured to improve the control accuracy of a controlled object at low cost. The control device 1 according to this embodiment will be described below. However, the control device 1 is not limited to the following embodiment, and various modifications are possible within the scope of the gist thereof.
[0011] 1 is a block diagram showing a schematic configuration of a control device 1 and a master device 2 (an example of a "command device"). The control device 1 communicates with the master device 2 based on a synchronization signal generated by the master device 2, and controls the driving of a control target 3. In this embodiment, the control device 1 communicates with the master device 2 by LIN (Local Interconnect Network) communication in which the master device 2 controls transmission and reception, and an example will be described in which the control target 3 is a motor M.
[0012] 1, the master device 2 includes a clock signal generating unit 21, a communication signal control unit 22, and a communication signal input / output unit 23. The control device 1 includes a communication signal input / output unit 10, a specified value information storage unit 11, a clock signal generating unit 12, a measurement value information acquiring unit 13, a correction value calculating unit 14, a command value information acquiring unit 15, a corrected command value calculating unit 16, and a control unit 17. Each functional unit is constructed using hardware or software, or both, with a CPU as its core component to perform processing related to communication and control of the drive of the controlled object 3.
[0013] The clock signal generating unit 21 generates a clock signal based on the vibration of a quartz oscillator, for example. Specifically, the vibration of the quartz oscillator is divided to generate a clock signal that oscillates at a desired oscillation frequency. Because the vibration of a quartz oscillator has small errors and temperature fluctuations, the clock signal generating unit 21 can generate a clock signal that oscillates at a highly accurate oscillation frequency (for example, ±0.5%). This clock signal is used as a synchronization signal in communication with the control device 1. Here, it is assumed that the oscillation frequency of the synchronization signal is f1 [Hz]. For ease of understanding, the clock signal generated by the clock signal generating unit 21 will also be referred to as a first clock signal.
[0014] The communication signal control unit 22 generates a communication signal and communicates with the control device 1 based on the synchronization signal. This communication is performed via the communication signal input / output unit 23.
[0015] The specified value information storage unit 11 stores, as specified value information, a specified value that specifies the oscillation frequency of the synchronization signal generated in the master device 2. The oscillation frequency of the synchronization signal generated in the master device 2 corresponds to the oscillation frequency of the high-precision clock signal generated by the clock signal generation unit 21, i.e., the oscillation frequency of the first clock signal. In this embodiment, the clock signal generation unit 21 generates a first clock signal with an oscillation frequency of f1 [Hz]. Therefore, the specified value that specifies the oscillation frequency of the synchronization signal corresponds to the oscillation frequency f1 [Hz]. Therefore, the specified value information storage unit 11 stores the oscillation frequency f1 [Hz] of this clock signal (first clock signal) as specified value information.
[0016] The clock signal generating unit 12 generates a clock signal with a predetermined oscillation frequency. This clock signal is used by the control device 1, and the control device 1 performs control based on this clock signal. Here, the clock signal generating unit 12 is configured using, for example, an RC oscillation circuit. Therefore, the clock signal generating unit 12 generates a clock signal with lower accuracy than the clock signal generated by the clock signal generating unit 21, which is configured using a quartz oscillator. The clock signal generated by the clock signal generating unit 12 has an oscillation frequency f2 [Hz], which is 10 times the oscillation frequency f1 [Hz]. For ease of understanding, the clock signal generated by the clock signal generating unit 12 will also be referred to as a second clock signal below.
[0017] The measurement value information acquiring unit 13 acquires, as measurement value information, a measurement value obtained by measuring the oscillation frequency of the synchronization signal transmitted from the master device 2 based on the clock signal generated by the clock signal generating unit 12. As described above, the oscillation frequency of the second clock signal generated by the clock signal generating unit 12 is set to f2 [Hz]. Also, as described above, the accuracy of the oscillation frequency of the second clock signal is lower than the accuracy of the oscillation frequency of the first clock signal. However, regardless of the oscillation frequency of the second clock signal being the intended value, the measurement value information acquiring unit 13 recognizes the oscillation frequency of the second clock signal generated by the clock signal generating unit 12 as f2 [Hz]. For example, the measurement value information acquiring unit 13 counts the number of pulses of the second clock signal included in one period of the synchronization signal transmitted from the master device 2 and calculates the period of the synchronization signal based on the counting result. Then, the oscillation frequency of the first clock signal is measured based on the calculated period.
[0018] For example, as shown in (1) of Fig. 2, suppose the oscillation frequency f1 of the first clock signal is 20 kHz and the set value of the oscillation frequency f2 of the second clock signal is 200 kHz. In this case, if the actual oscillation frequency f2 of the second clock signal is 200 kHz, 10 pulses of the second clock signal will be included in one period of the synchronization signal transmitted from the master device 2 (#10). In this case, the measurement value information acquisition unit 13 recognizes that the oscillation frequency of the synchronization signal is 20 kHz (#11).
[0019] However, as described above, the accuracy of the oscillation frequency of the second clock signal is low, so there is a possibility that it may deviate from the intended value (200 kHz in this case). In this case, the measurement value information acquiring unit 13 cannot determine whether the oscillation frequency f2 of the second clock signal deviates from the intended value (200 kHz), and so assumes that the second clock signal is oscillating at the intended oscillation frequency, counts the number of pulses of the second clock signal contained in one period of the synchronization signal transmitted from the master device 2, and measures the oscillation frequency of the synchronization signal transmitted from the master device 2 based on this counting result.
[0020] For example, as shown in FIG. 2 (2), if the actual oscillation frequency f2 of the second clock signal is 220 kHz, 11 pulses of the second clock signal will be included in one cycle of the synchronization signal transmitted from the master device 2 (#20). In this case, the measurement value information acquiring unit 13 will recognize that the oscillation frequency of the synchronization signal is 18.18 kHz (#21). Also, if the actual oscillation frequency f2 of the second clock signal is 180 kHz, as shown in FIG. 2 (3), 9 pulses of the second clock signal will be included in one cycle of the synchronization signal transmitted from the master device 2 (#30). In this case, the measurement value information acquiring unit 13 will recognize that the oscillation frequency of the synchronization signal is 22.22 kHz (#31).
[0021] Returning to Fig. 1, the correction value calculation unit 14 calculates a correction value α for correcting the command value information transmitted from the master device 2 based on the specified value information and the measurement value information. The specified value information is stored in the specified value information storage unit 11, and in this embodiment is stored as f1 [Hz]. The measurement value information is acquired by the measurement value information acquisition unit 13 based on the second clock signal generated by the clock signal generation unit 12.
[0022] The correction value α is the value obtained by dividing the specified value by the measured value. The specified value is indicated by the specified value information stored in the specified value information storage unit 11. The measured value is acquired by the measured value information acquisition unit 13. For example, as shown in (1) of FIG. 2, if the measured value obtained by the measured value information acquisition unit 13 is 20 kHz (#11), the correction value α is 1, which is the value obtained by dividing the period of the specified value by the period of the measured value (#12).
[0023] On the other hand, as shown in (2) of Fig. 2, when the measurement value obtained by the measurement value information obtaining unit 13 is 18.18 kHz (#21), the correction value α becomes 0.909, which is the value obtained by dividing the period of the specified value by the period of the measured value (#22).Also, as shown in (3) of Fig. 2, when the measurement value obtained by the measurement value information obtaining unit 13 is 22.22 kHz (#31), the correction value α becomes 1.111, which is the value obtained by dividing the period of the specified value by the period of the measured value (#32).
[0024] Returning to FIG. 1, the command value information acquiring unit 15 acquires command value information indicating a command value for the motor M from the master device 2. The command value for the motor M corresponds to a command rotation speed for the motor M. Such a command rotation speed is transmitted from the master device 2 to the control device 1 by a signal (communication signal). Specifically, the command value information acquiring unit 15 transmits information consisting of a preset number of bits (for example, "00110000" in the case of information consisting of 8 bits) during a predetermined period allocated within one cycle of the communication signal. The command value information acquiring unit 15 counts based on the second clock signal generated by the clock signal generating unit 12 to acquire the command value information. Specifically, the predetermined period is defined by information consisting of a preset number of bits, and the predetermined period is counted based on the second clock signal generated by the clock signal generating unit 12, and the information consisting of the bits during this counted period is treated as command value information.
[0025] The corrected command value calculation unit 16 calculates a corrected command value by correcting the command value information based on the correction value α. The command value information acquisition unit 15 acquires the command value information. The correction value α is calculated by the correction value calculation unit 14.
[0026] If the oscillation frequency f2 of the second clock signal in the control device 1 does not deviate from the set value (if it oscillates at f2=200 kHz), the correction value α is 1 (#12). In this case, for example, if the command value information indicates a command value that sets the command rotation speed of the motor M to 1000 rpm, the corrected command value calculated by the corrected command value calculation unit 16 will be 1000 rpm, as shown in (1) of Fig. 3 (#13).
[0027] On the other hand, if the oscillation frequency f2 of the second clock signal in the control device 1 is higher than the set value (for example, if it oscillates at f2=220 kHz), the correction value α is 0.909 (#22). In this case, if the command value information indicates a command value that sets the command rotation speed of the motor M to 1000 rpm, the corrected command value calculated by the corrected command value calculation unit 16 will be 909 rpm (#23), as shown in FIG. 3 (2). This allows the command value to be reduced by the amount that the second clock signal in the control device 1 is faster than the set value (the oscillation frequency is higher).
[0028] Furthermore, if the oscillation frequency f2 of the second clock signal in the control device 1 is lower than the set value (for example, if it oscillates at f2=180 kHz), the correction value α is 1.111 (#32). In this case, if the command value information indicates a command value that sets the command rotation speed of the motor M to 1000 rpm, the corrected command value calculated by the corrected command value calculation unit 16 will be 1111 rpm (#33), as shown in FIG. 3 (3). This allows the command value to be increased by the amount that the second clock signal in the control device 1 is slower than the set value (the oscillation frequency is lower).
[0029] 1, the control unit 17 controls the drive of the control target 3 based on the corrected command value. That is, in this embodiment, the corrected command value is transmitted to the control unit 17 from the corrected command value calculation unit 16, and the control unit 17 controls the drive of the motor M so that the rotation speed of the motor M becomes the rotation speed indicated by the corrected command value.
[0030] As described above, according to the control device 1, even if the control device 1 does not use an expensive oscillator with a high accuracy of oscillation frequency, but rather uses a clock signal generating unit 12 configured using an inexpensive oscillator, by utilizing communication information with the master device 2, high-quality control can be performed.
[0031] Other Embodiments
[0032] Next, other embodiments of the control device 1 will be described.
[0033] In the above embodiment, the correction value α is described as being a value obtained by dividing a specified value by a measured value. However, for example, the correction value α may be a value obtained by multiplying a value obtained by dividing a specified value by a measured value by a predetermined coefficient. Such a coefficient is effective when, for example, mechanical loss on the motor M side inevitably causes deviation in the oscillation frequency of the signal from the master device 2 to the control device 1. Alternatively, such a coefficient may be a value that reduces the influence of external noise.
[0034] In the above embodiment, the control target 3 is described as the motor M. However, the control target 3 may be a device different from the motor M. In this case, the command value is a control command value for the device.
[0035] In the above embodiment, the communication between the master device 2 and the control device 1 has been described as LIN (Local Interconnect Network) communication in which the master device 2 controls transmission and reception. However, the communication between the master device 2 and the control device 1 may be PWM (Pulse Width Modulation) communication in which a command value is defined by a pulse width. In this case, the pulse period transmitted from the control device 1 can be measured based on the second clock signal, and the drive of the control target 3 can be controlled based on a corrected command value corrected by the correction value α. In this case, the command value information acquisition unit 15 measures the duration of the high period and the duration of the low period of the communication signal and calculates the pulse width to acquire the defined command value information.
[0036] In the above embodiment, an example has been described in which one control device 1 and one master device 2 are provided. However, there may be multiple control devices 1, in which case the processing according to the above embodiment may be performed in each of the multiple control devices 1. Also, there may be multiple master devices 2, in which case the processing according to the above embodiment may be performed in each of the multiple master devices 2 for one control device 1.
[0037] [Summary of the above embodiment] The control device 1 described above will now be outlined.
[0038] (1) The control device 1 communicates with the master device 2 (command device) based on a synchronization signal generated by the master device 2 and controls the drive of the motor M (controlled object 3). The control device 1 includes a specified value information storage unit 11 that stores, as specified value information, a specified value that specifies the oscillation frequency of the synchronization signal generated in the master device 2; a clock signal generation unit 12 that generates a clock signal of a predetermined oscillation frequency; a measurement value information acquisition unit 13 that acquires, as measurement value information, a measurement value obtained by measuring the oscillation frequency of the synchronization signal transmitted from the master device 2 based on the clock signal; a correction value calculation unit 14 that calculates a correction value α for correcting the command value information transmitted from the master device 2 based on the specified value information and the measurement value information; a command value information acquisition unit 15 that acquires, from the master device 2, command value information indicating a command value for the motor M; a corrected command value calculation unit 16 that calculates a corrected command value obtained by correcting the period of the command value information based on the correction value α; and a control unit 17 that controls the drive of the motor M based on the corrected command value.
[0039] According to this configuration, a correction value α for correcting the command value information is calculated based on a specified value that specifies the oscillation frequency of the synchronization signal generated in the master device 2 based on the specified value information stored in the specified value information storage unit 11 and a measured value of the oscillation frequency of the synchronization signal of the master device 2 measured on the control device 1 side and acquired by the measurement value information acquisition unit 13, and the calculated correction value α is used to correct the command value for the controlled object 3 transmitted from the master device 2. As a result, the control device 1 does not require a highly accurate oscillation frequency, and the drive of the controlled object 3 is controlled based on the corrected command value calculated by correcting the command value, so that the controlled object 3 can be controlled with high precision in accordance with the command value. Furthermore, since such correction of the command value can be performed appropriately at a desired timing, the drive of the controlled object 3 can be controlled with high precision in real time even if, for example, the environmental temperature of the control device 1 changes.
[0040] (2) In the control device 1 described in (1), the correction value α is preferably a value obtained by dividing a specified value by a measured value.
[0041] According to this configuration, the correction value calculation unit 14 can easily calculate the correction value α.
[0042] (3) In the control device 1 described in (1) or (2), it is preferable that the controlled object 3 is a motor M, and the command value is a command rotation speed of the motor M.
[0043] According to this configuration, even if the command value transmitted from the master device 2 to the control device 1 deviates from the desired value due to a clock signal deviation in the control device 1, the control device 1 can rotate the motor M at the desired command value.
[0044] (4) In the control device 1 according to any one of (1) to (3), the communication is preferably LIN communication in which the command device controls transmission and reception as the master device 2, or PWM communication.
[0045] In LIN communication or PWM communication, a clock signal oscillating at a highly accurate oscillation frequency is generated in the master device 2. Therefore, according to this configuration, by correcting the command value based on the clock signal oscillating at a highly accurate oscillation frequency by the amount of deviation in the oscillation frequency of the clock signal used in the control device 1, the command value output by the control device 1 to the controlled object 3 can be made to have the same accuracy as that of the master device 2 oscillating at a highly accurate oscillation frequency. Therefore, when transmitting a command value based on a clock signal, it is possible to appropriately control the driving of the controlled object 3. [Industrial Applicability]
[0046] The technology according to the present disclosure can be used in a control device that communicates with a command device based on a synchronization signal generated by the command device and controls the drive of a controlled object. [Explanation of symbols]
[0047] 1: control device, 2: master device (command device), 3: controlled object, 11: specified value information storage unit, 12: clock signal generation unit, 13: measurement value information acquisition unit, 14: correction value calculation unit, 15: command value information acquisition unit, 16: corrected command value calculation unit, 17: control unit, M: motor, α: correction value
Claims
1. A control device that communicates with a command device based on a synchronization signal generated by the command device and controls driving of a control target, a specified value information storage unit that stores, as specified value information, a specified value that specifies the oscillation frequency of the synchronization signal generated by the command device; a clock signal generating unit that generates a clock signal having a predetermined oscillation frequency; a measurement value information acquiring unit that acquires, as measurement value information, a measurement value obtained by measuring an oscillation frequency of the synchronization signal transmitted from the command device based on the clock signal; a correction value calculation unit that calculates a correction value for correcting command value information transmitted from the command device based on the specified value information and the measurement value information; a command value information acquisition unit that acquires command value information indicating a command value for the controlled object from the command device; a corrected command value calculation unit that calculates a corrected command value by correcting a period of the command value information based on the correction value; a control unit that controls the drive of the controlled object based on the corrected command value; A control device comprising:
2. The control device according to claim 1 , wherein the correction value is a value obtained by dividing the specified value by the measured value.
3. the controlled object is a motor, 3. The control device according to claim 1, wherein the command value is a command rotation speed of the motor.
4. 3. The control device according to claim 1, wherein the communication is LIN communication or PWM communication in which the command device controls transmission and reception as a master device.
Citation Information
Patent Citations
Data communications system
JP2005303632A