Control device

Abstract

The invention provides a control device capable of improving control accuracy at low cost. The control device is provided with: a prescribed value information storage unit that stores, as prescribed value information, a prescribed value that defines the oscillation frequency of the synchronization signal generated by the command device; a clock signal generation unit that generates a clock signal having a predetermined oscillation frequency; a measured value information acquisition unit that acquires, as measured value information, a measured value obtained by measuring the oscillation frequency of the synchronization signal transmitted from the command device, on the basis of the clock signal; a correction value calculation unit that calculates, on the basis of the prescribed value information and the measured value information, a correction value for correcting the command value information transmitted from the command device; a command value information acquisition unit that acquires command value information indicating a command value for a control object from a command device; a corrected command value calculation unit that calculates a corrected command value obtained by correcting the cycle of the command value information on the basis of the correction value; and a control unit that controls the driving of the control object on the basis of the corrected command value.

Description

Technical Field

[0001] The present invention relates to a control device that controls driving of a control object by communicating with an instruction device based on a synchronization signal generated by the instruction device. Background Art

[0002] In the past, for example, a control device that obtains control instructions by communicating with a host system and controls the drive of the controlled object based on the obtained control instructions. As one of the communications with such a host system, there is a master-slave communication, for example. In the master-slave communication, independent clock signals are used. If the oscillation frequency of the clock signal is different between the transceiver on the host side and the transceiver on the slave side, the above-mentioned control instructions may not be properly transmitted. Therefore, a crystal oscillator or a ceramic oscillator is respectively installed on the transceiver on the host side and the transceiver on the slave side to reduce the difference in the oscillation frequency of the clock signals of the two. The oscillation frequency of such a crystal oscillator or ceramic oscillator is highly accurate and has low temperature dependence, so it can achieve high communication quality. However, compared with, for example, an LC oscillator circuit composed of a coil and a capacitor, or an RC oscillator circuit composed of a resistor and a capacitor, a crystal oscillator or a ceramic oscillator is more expensive, so there is a problem of increasing the cost of the entire system.

[0003] Therefore, in the data communication system described in Patent Document 1, only a crystal oscillator is installed in the master device, while the slave devices are each equipped with a voltage-controlled oscillator (VCO) consisting of an RC oscillator circuit or an LC oscillator circuit using a varactor diode. In the slave device, the oscillation frequency of the clock signal generated by the VCO is adjusted based on the signal received from the master device. This allows for a low-cost slave device.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-303632 Summary of 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 a signal received from the master device. Therefore, the voltage-controlled oscillator must be configured to allow external frequency adjustment. The addition of an adjustment circuit for this frequency adjustment is a major cost increase. Furthermore, low-cost LC and RC oscillator circuits are typically built into integrated circuits. Existing integrated circuits are not configured to allow external adjustment, requiring a new design or the installation of a separate crystal oscillator. Furthermore, through functions supported by communication standards such as LIN (Local Interconnect Network) communication, slave devices can sometimes ensure communication quality even without using a high-precision clock signal generation circuit. In such systems, as a slave device, improving the control accuracy of the controlled object requires high-precision clock signal oscillation frequency. Therefore, the data communication system described in Patent Document 1 has room for improvement in terms of cost-effectively improving the control accuracy of the controlled object.

[0006] Therefore, a control device capable of improving the control accuracy of a controlled object at low cost is desired.

[0007] The characteristic structure of the control device of the present invention is that it controls the drive of the controlled object by communicating with the command device based on a synchronization signal generated by the command device, wherein the control device comprises: a specified value information storage unit, which stores the specified value of the oscillation frequency of the synchronization signal generated in the command device as specified value information; a clock signal generating unit, which generates a clock signal of a specified oscillation frequency; a measured value information acquiring unit, which acquires the measured value of the oscillation frequency of the synchronization signal transmitted from the command device as measured value information based on the clock signal; a correction value calculating unit, which calculates a correction value for correcting the command value information transmitted from the command device based on the specified value information and the measured value information; an command value information acquiring unit, which acquires command value information representing the command value for the controlled object from the command device; a corrected command value calculating unit, which calculates a corrected command value after correcting the period of the command value information based on the correction value; and a control unit, which controls the drive of the controlled object based on the corrected command value.

[0008] According to this characteristic structure, a correction value for correcting the command value information is calculated based on a specified value for the oscillation frequency of the synchronization signal generated by the host device, stored in the specified value information storage unit, and a measured value of the oscillation frequency of the host device's synchronization signal, measured on the control device side and acquired by the measured value information acquisition unit. This calculated correction value is then used to correct the command value for the control object transmitted from the host device. As a result, the control device does not need to have a high-precision oscillation frequency, and the drive of the control object is controlled using a corrected command value calculated based on the corrected command value. Therefore, the control object can be controlled with high precision according to the command value. Furthermore, such command value correction can be appropriately performed at the desired timing, so that, for example, even when the ambient temperature of the control device changes, the drive of the control object can be controlled in real time and with high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a block diagram showing the configuration of a control device and a host device.

[0010] Figure 2 It is an explanatory diagram of calculation of correction value.

[0011] Figure 3 This is an explanatory diagram of calculation of the correction completion command value.

[0012] Description of reference numerals:

[0013] 1: Control device, 2: Host device (command device), 3: Control target, 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 DETAILED DESCRIPTION

[0014] The control device of the present invention is configured to improve the control accuracy of the controlled object at a low cost. A control device 1 according to this embodiment will be described below. However, the control device 1 is not limited to the following embodiment and can be modified in various ways without departing from the spirit and scope of the present invention.

[0015] Figure 1 This block diagram schematically illustrates the configuration of a control device 1 and a host device 2 (an example of a "command device"). The control device 1 communicates with the host device 2 based on a synchronization signal generated by the host device 2 to control the driving of a controlled object 3. In this embodiment, the control device 1 communicates with the host device 2 using LIN (Local Interconnect Network) communication, with the host device 2 controlling transmission and reception. The controlled object 3 is a motor M.

[0016] like Figure 1 As shown, the host device 2 is configured to include a clock signal generating unit 21, a communication signal control unit 22, and a communication signal input / output unit 23. Furthermore, the control device 1 is configured to include a communication signal input / output unit 10, a specified value information storage unit 11, a clock signal generating unit 12, a measured value information acquiring unit 13, a correction value calculating unit 14, a command value information acquiring unit 15, a correction-completed command value calculating unit 16, and a control unit 17. To perform processing related to communication and control of the drive of the controlled object 3, each functional unit is constructed using hardware, software, or both, with the CPU as the core component.

[0017] The clock signal generating unit 21 generates a clock signal based on the vibration of a crystal oscillator, for example. Specifically, the vibration of the crystal oscillator is divided to generate a clock signal that oscillates at a desired oscillation frequency. Therefore, since the error and temperature fluctuation of the vibration of the crystal oscillator are small, a clock signal that oscillates at an oscillation frequency with high precision (for example, ±0.5%) can be obtained from the clock signal generating unit 21. This clock signal is used as a synchronization signal in communication with the control device 1. Here, the oscillation frequency of the synchronization signal is set to f1 [Hz]. In addition, for ease of understanding below, the clock signal generated by the clock signal generating unit 21 is sometimes referred to as the first clock signal.

[0018] 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 .

[0019] The prescribed value information storage unit 11 stores the prescribed value that specifies the oscillation frequency of the synchronization signal generated in the host device 2 as prescribed value information. The oscillation frequency of the synchronization signal generated in the host device 2 corresponds to the oscillation frequency of the high-precision clock signal generated by the clock signal generation unit 21, that is, 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 prescribed value that specifies the oscillation frequency of the synchronization signal corresponds to the oscillation frequency f1 [Hz]. Therefore, the prescribed value information storage unit 11 stores the oscillation frequency f1 [Hz] of the clock signal (first clock signal) as prescribed value information.

[0020] The clock signal generating unit 12 generates a clock signal of a predetermined oscillation frequency. This clock signal is a clock signal used in the control device 1, and control is performed in the control device 1 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 configured using a crystal oscillator. The clock signal generated by the clock signal generating unit 12 has an oscillation frequency of f2 [Hz], which is 10 times the oscillation frequency of f1 [Hz]. For ease of understanding, the clock signal generated by the clock signal generating unit 12 is sometimes referred to as the second clock signal.

[0021] The measured value information acquisition unit 13 acquires the measured value of the oscillation frequency of the synchronization signal transmitted from the host device 2 as the measured value information based on the clock signal generated by the clock signal generation unit 12. As described above, the oscillation frequency of the second clock signal generated by the clock signal generation unit 12 is set to f2 [Hz]. In addition, 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 expected value of the oscillation frequency of the second clock signal, the measured value information acquisition unit 13 assumes that the oscillation frequency of the second clock signal generated by the clock signal generation unit 12 is f2 [Hz]. For example, the measured value information acquisition unit 13 counts the number of pulses of the second clock signal contained in one cycle of the synchronization signal transmitted from the host device 2, and calculates the cycle of the synchronization signal based on the counted result. Then, based on the calculated cycle, the oscillation frequency of the first clock signal is measured.

[0022] For example, Figure 2 As shown in (1), the oscillation frequency f1 of the first clock signal is set to 20 kHz, and the set value of the oscillation frequency f2 of the second clock signal is set to 200 kHz. In this case, if the actual oscillation frequency f2 of the second clock signal is 200 kHz, then the pulses of the second clock signal will include 10 pulses within one cycle of the synchronization signal transmitted from the host 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).

[0023] However, as described above, the oscillation frequency of the second clock signal has low accuracy and may deviate from the desired value (here, 200 kHz). In this case, the measured value information acquisition unit 13 does not know whether the oscillation frequency f2 of the second clock signal has deviated from the desired value (200 kHz). The measured value information acquisition unit 13 assumes that the second clock signal oscillates at the desired oscillation frequency and counts the number of pulses of the second clock signal contained in one cycle of the synchronization signal transmitted from the host device 2. Based on the counted number, the oscillation frequency of the synchronization signal transmitted from the host device 2 is measured.

[0024] For example, Figure 2 As shown in (2), if the actual oscillation frequency f2 of the second clock signal is 220k〔Hz〕, then within one cycle of the synchronization signal transmitted from the host device 2, the pulse of the second clock signal includes 11 pulses (#20). In this case, the measured value information acquisition unit 13 recognizes that the oscillation frequency of the synchronization signal is 18.18k〔Hz〕(#21). In addition, if the actual oscillation frequency f2 of the second clock signal is 180k〔Hz〕, then Figure 2 As shown in (3), the second clock signal includes nine pulses (#30) within one cycle of the synchronization signal transmitted from the host device 2. In this case, the measurement value information acquisition unit 13 recognizes that the oscillation frequency of the synchronization signal is 22.22 kHz (#31).

[0025] return Figure 1 Based on the specified value information and the measured value information, the correction value calculation unit 14 calculates the correction value α used to correct the command value information transmitted from the host device 2. The specified value information is stored in the specified value information storage unit 11 and, in this embodiment, is stored as f1 [Hz]. Based on the second clock signal generated by the clock signal generation unit 12, the measured value information acquisition unit 13 acquires the measured value information.

[0026] The correction value α is equivalent to the value obtained by dividing the specified value by the measured value. The specified value is represented 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, Figure 2 As shown in (1), when the measurement value acquired by the measurement value information acquisition unit 13 is 20 kHz (#11), the correction value α is 1 obtained by dividing the period of the predetermined value by the period of the measurement value (#12).

[0027] On the other hand, Figure 2 As shown in (2), when the measurement value acquired by the measurement value information acquisition unit 13 is 18.18 k[Hz] (#21), the correction value α is 0.909 (#22), which is the value obtained by dividing the period of the specified value by the period of the measurement value. Figure 2As shown in (3), when the measurement value acquired by the measurement value information acquisition unit 13 is 22.22 kHz (#31), the correction value α is 1.111 (#32), which is the value obtained by dividing the period of the predetermined value by the period of the measurement value.

[0028] return Figure 1 , the instruction value information acquisition unit 15 acquires instruction value information representing the instruction value for the motor M from the host device 2. The instruction value for the motor M refers to the instruction speed of the motor M. Such an instruction speed is transmitted from the host device 2 to the control device 1 via a signal (communication signal). Specifically, within a specified period allocated within one cycle of the communication signal, information consisting of a predetermined number of bits (for example, "00110000" in the case of information consisting of 8 bits, etc.) is transmitted. The instruction value information acquisition unit 15 counts based on the second clock signal generated by the clock signal generation unit 12 to acquire the instruction value information. Specifically, within a specified period, information consisting of a predetermined number of bits is specified, and information consisting of the number of bits is counted based on the second clock signal generated by the clock signal generation unit 12, and the information consisting of the counted bits is processed as instruction value information.

[0029] The corrected command value calculation unit 16 calculates a corrected command value obtained by correcting the command value information based on the correction value α. The command value information is acquired by the command value information acquisition unit 15. The correction value α is calculated by the correction value calculation unit 14.

[0030] If the oscillation frequency f2 of the second clock signal in the control device 1 does not deviate from the set value (in the case of oscillation at f2 = 200 kHz), the correction value α is 1 (#12). In this case, for example, if the command value information is information indicating that the command speed of the motor M is set to 1000 rpm, Figure 3 As shown in (1), the correction completion command value calculated by the correction completion command value calculation unit 16 is 1000 rpm (#13).

[0031] On the other hand, when the oscillation frequency f2 of the second clock signal in the control device 1 deviates from the set value (for example, when oscillating at f2 = 220 k [Hz]), the correction value α is 0.909 (#22). In this case, if the command value information is information indicating that the command speed of the motor M is set to 1000 rpm, as shown in FIG. Figure 3 As shown in (2), the corrected command value calculated by the corrected command value calculation unit 16 is 909 rpm (#23). This allows the command value to be reduced by the amount by which the second clock signal in the control device 1 advances relative to the set value (the oscillation frequency becomes higher).

[0032] In addition, when the oscillation frequency f2 of the second clock signal in the control device 1 deviates from the set value (for example, when oscillating at f2 = 180 k [Hz]), the correction value α is 1.111 (#32). In this case, if the command value information is information indicating that the command speed of the motor M is set to 1000 rpm, as shown in FIG. Figure 3 As shown in (3), the corrected command value calculated by the corrected command value calculation unit 16 is 1111 revolutions (#33). This allows the command value to be increased by the amount by which the second clock signal in the control device 1 slows down (oscillation frequency decreases) relative to the set value.

[0033] return Figure 1 The control unit 17 controls the driving of the controlled object 3 based on the corrected command value. That is, in this embodiment, the corrected command value is transmitted from the corrected command value calculation unit 16 to the control unit 17, and the driving of the motor M is controlled so that the rotational speed of the motor M reaches the rotational speed indicated by the corrected command value.

[0034] As described above, according to the control device 1, even if the control device 1 does not use an expensive oscillator with high oscillation frequency accuracy but uses a clock signal generating unit 12 composed of an inexpensive oscillator, it is possible to perform high-quality control by utilizing communication information between the host device 2.

[0035] [Other Implementation Methods]

[0036] Next, other embodiments of the control device 1 will be described.

[0037] In the above embodiment, the correction value α is described as being the value obtained by dividing the measured value by the prescribed value. However, for example, the correction value α may be the value obtained by multiplying the value obtained by dividing the measured value by the prescribed value by a prescribed coefficient. Such a coefficient is effective when, for example, the oscillation frequency of the signal from the host device 2 to the control device 1 inevitably deviates due to mechanical losses on the motor M side. Alternatively, such a coefficient may be a value that reduces the influence of external noise.

[0038] 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 of the device.

[0039] In the above embodiment, the communication between the host device 2 and the control device 1 is described as LIN (Local Interconnect Network) communication, in which the host device 2 controls transmission and reception. However, the communication between the host device 2 and the control device 1 may also be PWM (Pulse Width Modulation) communication, in which the command value is specified by the 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 controlled object 3 can be controlled using the corrected command value corrected using the correction value α. In this case, the command value information acquisition unit 15 measures the time during which the communication signal is high and the time during which it is low, and acquires the command value information specified by the calculated pulse width.

[0040] In the above embodiment, the case where one control device 1 and one host device 2 are provided is used as an example. However, there may be multiple control devices 1, in which case the processing of the above embodiment can be performed in each of the multiple control devices 1. Furthermore, there may be multiple host devices 2, in which case the processing of the above embodiment can be performed in each of the multiple host devices 2 corresponding to one control device 1.

[0041] [Overview of the above embodiment]

[0042] Hereinafter, the outline of the control device 1 described above will be described.

[0043] (1) The control device 1 communicates with the host device 2 based on the synchronization signal generated by the host device 2 (command device) to control the drive of the motor M (controlled object 3), and the control device 1 has: a specified value information storage unit 11, which stores the specified value of the oscillation frequency of the synchronization signal generated in the command device 2 as specified value information; a clock signal generating unit 12, which generates a clock signal of the specified oscillation frequency; a measured value information acquiring unit 13, which acquires the measured value of the oscillation frequency of the synchronization signal transmitted from the command device 2 as measured value information based on the clock signal; a correction value calculating unit 14, which calculates the correction value α for correcting the command value information transmitted from the command device 2 based on the specified value information and the measured value information; a command value information acquiring unit 15, which acquires the command value information representing the command value for the motor M from the command device 2; a corrected command value calculating unit 16, which calculates the corrected command value after correcting the period of the command value information based on the correction value α; and a control unit 17, which controls the drive of the motor M based on the corrected command value.

[0044] According to this configuration, a correction value α for correcting the command value information is calculated based on the specified value defining the oscillation frequency of the synchronization signal generated by the host device 2, stored in the specified value information storage unit 11, and the measured value of the oscillation frequency of the synchronization signal of the host device 2, measured on the control device 1 side and acquired by the measured value information acquisition unit 13. This calculated correction value α is then used to correct the command value for the controlled object 3 transmitted from the host device 2. This eliminates the need for a high-precision oscillation frequency on the control device 1 side, and allows the controlled object 3 to be controlled with high precision based on the corrected command value calculated based on the corrected command value. Furthermore, this command value correction can be performed appropriately at a desired timing, enabling real-time and high-precision control of the controlled object 3 even when the ambient temperature of the control device 1 changes, for example.

[0045] (2) In the control device 1 described in (1), preferably, the correction value α is a value obtained by dividing a predetermined value by a measured value.

[0046] According to this configuration, the correction value calculation unit 14 can easily calculate the correction value α.

[0047] (3) In the control device 1 described in (1) or (2), preferably, the controlled object 3 is a motor M, and the command value is a command rotation speed of the motor M.

[0048] According to this configuration, even when the command value transmitted from the host device 2 to the control device 1 deviates from a desired value due to variations in the clock signal in the control device 1 , the control device 1 can rotate the motor M at the desired command value.

[0049] (4) In the control device 1 described in any one of (1) to (3), preferably, the communication is LIN communication or PWM communication in which the instruction device as the host device 2 controls transmission and reception.

[0050] In LIN communication or PWM communication, a clock signal oscillating at a high-precision frequency is generated in host device 2. Therefore, according to this configuration, by using the clock signal oscillating at a high-precision frequency as a basis and correcting the command value by the amount of deviation from the oscillation frequency of the clock signal used in control device 1, the command value output by control device 1 to controlled object 3 can be set to an accuracy equivalent to that of host device 2 oscillating at a high-precision frequency. Therefore, when the command value is transmitted based on the clock signal, the drive of controlled object 3 can be appropriately controlled.

[0051] Industrial applicability

[0052] The technology of the present invention can be applied to a control device that controls the driving of a controlled object by communicating with a command device based on a synchronization signal generated by the command device.

Claims

1. A control device that controls the driving of a controlled object by communicating with an instruction device based on a synchronization signal generated by the instruction device, wherein: The control device has: a prescribed value information storage unit for storing, as prescribed value information, a prescribed value that specifies the oscillation frequency of the synchronization signal generated in the instruction device; A clock signal generating unit that generates a clock signal of a predetermined oscillation frequency; a measurement value information acquisition 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 the command value information transmitted from the command device based on the prescribed value information and the measured value information; an instruction value information acquiring unit that acquires instruction value information indicating an instruction value for the control object from the instruction device; a corrected command value calculation unit that calculates a corrected command value obtained by correcting the period of the command value information based on the correction value; as well as The control unit controls driving of the control object based on the corrected command value.

2. The control device according to claim 1, wherein: The correction value is a value obtained by dividing the predetermined value by the measured value.

3. The control device according to claim 1 or 2, wherein: The control object is a motor, The command value is a command rotation speed of the motor.

4. The control device according to claim 1 or 2, wherein: The communication is LIN communication or PWM communication in which the command device controls transmission and reception as a host device.

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