WO2015087403A1

WO2015087403A1 - Motor control system, motor control device, device being controlled, and motor control method

Info

Publication number: WO2015087403A1
Application number: PCT/JP2013/083143
Authority: WO
Inventors: 古賀　英嗣
Original assignee: 株式会社安川電機
Priority date: 2013-12-10
Filing date: 2013-12-10
Publication date: 2015-06-18
Also published as: WO2015087577A1

Abstract

A motor control system in one mode of an embodiment comprises a device being controlled, said device having a motor and a communication unit, and a motor control device that controls said motor on the basis of a carrier signal, the value of which varies cyclically. The motor control device has a communication unit and a specification unit. Said communication unit exchanges information with the communication unit in the device being controlled, and the specification unit specifies, on the basis of the cycle characteristics of the value of the carrier signal, a communication period in which to make the communication unit in the motor control device exchange the aforementioned information with the communication unit in the device being controlled.

Description

Motor control system, motor control device, control target device, and motor control method

The disclosed embodiment relates to a motor control system, a motor control device, a control target device, and a motor control method.

Conventionally, a control target device including a motor and a motor control device that controls the operation of the motor are received. The motor control device receives information indicating the state of the motor from the control target device, and operates the motor based on the received information. There is a motor control system for feedback control.

As such a motor control system, an information transmission signal line indicating the rotation position of the motor is provided by transmitting information indicating the rotation position of the motor from the control target apparatus to the motor control apparatus via a power line that supplies power to the motor. Some have reduced wiring (for example, see Patent Document 1).

In this motor control system, the position detection device always transmits information indicating the rotational position of the motor to the motor control device. On the other hand, the motor control device temporarily stops the switching operation of the circuit that drives the motor, and performs drive control of the motor based on information indicating the rotational position of the motor received during the stop period of the switching operation. Thereby, an adverse effect on the drive control due to the switching noise is reduced.

JP 2008-278657 A

However, in the drive control of the motor based on the information received during the stop period of the switching operation, the responsiveness of the drive control is impaired, and there is a problem that the performance of the drive control for the motor is deteriorated.

One aspect of the embodiments has been made in view of the above, and a motor control system, a motor control device, and a control target device that can improve the performance of drive control on a motor while reducing the influence of switching noise. And a motor control method.

A motor control system according to an aspect of an embodiment includes a control target device including a motor and a communication unit, and a motor control device that performs drive control of the motor based on a carrier signal whose signal value periodically changes. Including. The motor control device includes a communication unit and a specifying unit. The communication unit communicates information with the communication unit of the device to be controlled. The specifying unit specifies a communication period in which the communication unit of the motor control device performs communication of the information based on a periodic characteristic of the signal value.

According to one embodiment of the present invention, it is possible to provide a motor control system, a motor control device, a control target device, and a motor control method that can improve the performance of drive control on a motor while reducing the influence of switching noise. Can do.

FIG. 1 is an explanatory diagram illustrating an appearance of a motor control system according to the embodiment. FIG. 2 is a block diagram illustrating a configuration of the robot and the motor control device according to the embodiment. FIG. 3 is a circuit diagram illustrating an example of the configuration of the power conversion unit according to the embodiment. FIG. 4 is an explanatory diagram for explaining the operation of the power conversion unit according to the embodiment. FIG. 5 is a block diagram illustrating details of the configuration of the motor control device and the robot according to the embodiment. FIG. 6 is an explanatory diagram for describing a procedure for specifying a communication period according to the embodiment. FIG. 7 is a sequence diagram illustrating communication performed in the motor control system according to the embodiment. FIG. 8 is an explanatory diagram illustrating the timing of communication performed in the motor control system according to the embodiment. FIG. 9 is a flowchart illustrating processing executed by the control unit of the motor control device according to the embodiment. FIG. 10 is a flowchart illustrating processing executed by the state detection device according to the embodiment.

Hereinafter, embodiments of a motor control system, a motor control device, a control target device, and a motor control method disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

Hereinafter, a motor control system that performs drive control of a motor included in the robot by the motor control device will be described as an example. The control target of the motor control device according to the embodiment is not limited to the motor provided in the robot, and may be a motor provided in an arbitrary device.

FIG. 1 is an explanatory diagram showing an appearance of a motor control system 1 according to the embodiment. As shown in FIG. 1, the motor control system 1 includes a robot 2 and a motor control device 3. The robot 2 is a single-arm robot arm having six degrees of freedom.

Specifically, the robot 2 includes a base portion 20, a first arm 21, a second arm 22, a third arm 23, a fourth arm 24, a fifth arm 25, and an end effector 26. The base unit 20 is installed on an installation surface such as a horizontal floor surface, and includes a motor that rotates the first arm 21 around the axis S as a rotation axis.

The first arm 21 is connected to the base portion 20 and includes therein a motor that swings the second arm 22 about the axis L as a swing axis. The second arm 22 includes a motor whose base end is swingably connected to the first arm 21 and that rotates the third arm 23 about the axis U as a rotation axis inside the distal end.

The third arm 23 is rotatably connected to the tip of the second arm 22 and includes a motor that rotates the fourth arm 24 about the axis R as a rotation axis. The fourth arm 24 includes a motor whose base end is rotatably connected to the third arm 23 and swings the fifth arm 25 about the axis B as a swing axis.

The fifth arm 25 includes a motor whose base end is swingably connected to the distal end of the fourth arm 24 and rotates the end effector 26 about the axis T as a rotation axis. The end effector 26 is an arc welding torch whose base end portion is rotatably connected to the distal end portion of the fifth arm 25.

Thus, the robot 2 includes a total of six motors. The number of motors provided in the robot 2 may be 7 or more, or may be less than 6. The end effector 26 is not limited to an arc welding torch.

The motor control device 3 is a device that causes the robot 2 to perform a predetermined operation taught in advance by individually performing drive control of each motor included in the robot 2. The motor control device 3 and the robot 2 are connected by a first cable 41 and a second cable 42.

The first cable 41 is a wiring for supplying electric power for driving the motor from the motor control device 3 to the robot 2. The motor control device 3 adjusts the rotation speed, the rotation torque, and the like of each motor by controlling the voltage of the power supplied to each motor via the first cable 41.

The second cable 42 is a wiring for supplying electric power from the motor control device 3 to a state detection device E (see FIG. 2) described later included in the robot 2. The second cable 42 is also used for information communication periodically performed between the motor control device 3 and the robot 2.

For example, the robot 2 transmits information indicating the motor state such as the rotational position, rotational speed, and rotational acceleration of the motor to the motor control device 3. Information indicating the state of the motor is used by the motor control device 3 for, for example, feedback control of the motor (hereinafter simply referred to as “drive control”). In addition, the motor control device 3 transmits, for example, information that teaches the timing for transmitting information indicating the state of the motor from the robot 2 to the motor control device 3.

The motor control device 3 and the state detection device E modulate information related to drive control by, for example, OFDM (Orthogonal Frequency Division Multiplexing).

Then, the motor control device 3 and the state detection device E perform communication by superimposing information on the modulated drive control on the electric power supply current flowing through the second cable 42. As described above, in the motor control system 1, the second cable 42 is shared as the power supply wiring and the information communication wiring. As a result, the motor control system 1 realizes wiring saving for wirings used exclusively for communication of information related to drive control.

Next, the configuration of the robot 2 and the motor control device 3 according to the embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating configurations of the robot 2 and the motor control device 3 according to the embodiment. In FIG. 2, constituent elements necessary for drive control of the motor M are selectively illustrated, and the other constituent elements are not illustrated.

As shown in FIG. 2, the robot 2 includes a first control target device 51, a second control target device 52, a third control target device 53, a fourth control target device 54, a fifth control target device 55, and a sixth control target. A target device 56 is provided.

The first control target device 51 is provided in the base unit 20. The second control target device 52 is provided on the first arm 21. The third control target device 53 is provided on the second arm 22. The fourth control target device 54 is provided on the third arm 23. The fifth control target device 55 is provided on the fourth arm 24. The sixth control target device 56 is provided on the fifth arm 25. The arrangement positions of the first to sixth control target devices 51 to 56 are not limited to this.

The first control target device 51 includes a motor M, a state detection device E, and a coupler CP. The coupler CP is, for example, a photocoupler. The second to sixth control objects 52 to 56 have the same configuration as that of the first control object device 51 except that the sizes of the motors M are different. Therefore, the description of the configurations of the second to sixth control target devices 52 to 56 is omitted. In the following description, the first to sixth control target devices 51 to 56 will be referred to as the control target device 5 unless the first to sixth control target devices 51 to 56 are particularly distinguished.

The motor M is a rotating electrical machine that is connected to the motor control device 3 via the first cable 41 and rotates by three-phase AC power supplied from the motor control device 3. The robot 2 operates the first to fifth arms 21 to 25 and the end effector 26 corresponding to each control target device 5 by rotating the motor M included in each control target device 5 to perform a predetermined work.

The state detection device E is a rotary encoder that is connected to the motor M and detects the rotational position of the motor M. The state detection device E may be configured to detect any one or a plurality of states among the rotation position, rotation speed, and rotation acceleration of the motor M, and can detect the torque applied to the motor M. It may be a simple configuration. In addition, the state detection device E is connected to the second cable 42 via the coupler CP, and operates with electric power supplied via the second cable 42.

Then, for example, the state detection device E transmits position information indicating the detected rotational position of the motor M to the motor control device 3 via the second cable 42. Such position information is an example of information related to drive control. The configuration of the state detection device E will be described later with reference to FIG.

The motor control device 3 includes a control unit 30, power conversion units 31 to 36, a motor power supply unit 37, a control power supply unit 38, and a coupler CP. The motor power supply unit 37 is a power source that supplies three-phase AC power to each motor M of the robot 2 via the power conversion units 31 to 36 and the first cable 41. The control power supply unit 38 is a power source that supplies power to the control unit 30 and also supplies power to each control target device 5 included in the robot 2 via the coupler CP and the second cable 42.

Each of the power conversion units 31 to 36 operates according to control by the control unit 30 to adjust the voltage of power input from the motor power supply unit 37 and output the voltage to each motor M of the robot 2. It is. Here, with reference to FIG. 3 and FIG. 4, the configuration and operation of the power converters 31 to 36 will be described.

Since power converters 31 to 36 all have the same configuration and operation, the configuration and operation of power converter 31 will be described here, and the description of power converters 32 to 36 will be omitted. . FIG. 3 is a circuit diagram illustrating an example of the configuration of the power conversion unit 31 according to the embodiment, and FIG. 4 is an explanatory diagram for explaining the operation of the power conversion unit 31 according to the embodiment.

As shown in FIG. 3, the power conversion unit 31 includes a converter 31a, a smoothing circuit 31b, and an inverter 31c. The converter 31 a is a general rectifier circuit that includes six diodes connected in a full bridge and rectifies three-phase AC power (current) input from the motor power supply unit 37. The smoothing circuit 31b includes an inductor and a capacitor, and smoothes the pulsating current included in the current rectified by the converter 31a to a state closer to direct current.

The inverter 31c includes six switching elements a1, a2, b1, b2, c1, and c2 that are connected in a full bridge, and diodes that are connected in reverse parallel to the switching elements a1, a2, b1, b2, c1, and c2. Prepare. Each of the switching elements a1, a2, b1, b2, c1, and c2 is, for example, an IGBT (Insulated Gate Bipolar Transistor).

The inverter 31c performs switching for switching ON and OFF of the switching elements a1, a2, b1, b2, c1, and c2 according to control by the control unit 30, thereby converting the smoothed current into three-phase AC power. It is a circuit to convert.

That is, each switching element a1, a2, b1, b2, c1, c2 performs a switching operation based on a control signal input from the control unit 30 to each gate. The control unit 30 generates a control signal based on a so-called carrier comparison method, and outputs it to the gates of the switching elements a1, a2, b1, b2, c1, and c2.

For example, the control unit 30 compares the carrier signal ca indicated by the triangular wave in FIG. 4 with the voltage command values indicated by the three sine waves shown in FIG. 4 to determine the three control signals Sa, Sb, Sc shown in FIG. Is generated. As shown in FIG. 4, the carrier signal ca has a periodic characteristic in which the signal value (voltage value) periodically reaches an extreme value (maximum value and minimum value) between Vdc / 2 and −Vdc / 2. .

Here, the voltage command value a indicated by the solid line is for the U phase. The voltage command value b indicated by the dotted line is for the V phase. The voltage command value c indicated by the alternate long and short dash line is for the W phase. The control signal Sa is for the switching elements a1 and a2. The control signal Sb is for the switching elements b1 and b2. The control signal Sc is for the switching elements c1 and c2.

Then, as shown in FIG. 4, the control unit 30 becomes “1 (high level)” in a period in which the voltage command value a is higher than the signal value of the carrier signal ca, and the voltage command value is higher than the signal value of the carrier signal ca. A control signal Sa that becomes “0 (low level)” in a period in which a is low is generated.

Similarly, the control unit 30 compares the signal value of the carrier signal ca with the voltage command values b and c to generate control signals Sb and Sc. Then, the control unit 30 outputs the generated control signals Sa, Sb, Sc to the gates of the corresponding switching elements a1, a2, b1, b2, c1, c2.

Thereby, the switching element a1 is turned on when the control signal Sa is “1” and turned off when the control signal Sa is “0”. Conversely, the switching element a2 is turned on when the control signal Sa is “0” and turned off when the control signal Sa is “1”.

In addition, the switching element b1 is turned on when the control signal Sb is “1” and turned off when the control signal Sb is “0”. Conversely, the switching element b2 is turned on when the control signal Sb is “0” and turned off when the control signal Sb is “1”.

The switching element c1 is turned on when the control signal Sc is “1” and turned off when the control signal Sc is “0”. Conversely, the switching element c2 is turned on when the control signal Sc is “0” and turned off when the control signal Sc is “1”.

Returning to FIG. 2, the control unit 30 is connected to each of the power conversion units 31 to 36 via the communication bus 43. Then, the control unit 30 outputs the control signals Sa, Sb, and Sc to the power conversion units 31 to 36 via the bus 43, thereby controlling each motor M of the robot 2 by PWM (Pulse Width Modulation). To do.

Further, the control unit 30 receives position information indicating the rotational position of each motor M from each state detection device E of the robot 2 via the coupler CP and the second cable 42 for each predetermined period, and the received position information. Based on the above, the operation of the motor M is feedback-controlled.

In addition to the position information indicating the rotational position of the motor M, the control unit 30 may communicate various information regarding the drive control of each motor M with the control target device 5. For example, the control unit 30 also receives information indicating the rotational speed of the motor M and information indicating the rotational acceleration of the motor M from each control target device 5. In such a case, noise due to the switching operation of the switching elements a1, a2, b1, b2, c1, and c2 of the inverter 31c described above may be superimposed on information communicated via the second cable 42.

The noise superimposed on the information adversely affects the drive control of the motor M by the control unit 30. For example, when noise is superimposed on position information indicating the rotational position of the motor M, the control unit 30 has a reduced feedback control performance for the motor M.

Therefore, the control unit 30 sets a communication period in which noise due to switching operations of at least the switching elements a1, a2, b1, b2, c1, and c2 is not superimposed within the period of the carrier signal ca to the period characteristic of the carrier signal ca. Identify based on.

And the control part 30 improves the performance of the drive control with respect to the motor M, reducing the influence of switching noise by communicating between the control object apparatuses 5 in the specified communication period.

Next, the configuration of the motor control device 3 and the robot 2 including an example of a specific configuration of the control unit 30 will be described in more detail with reference to FIG. FIG. 5 is a block diagram illustrating details of the configurations of the motor control device 3 and the robot 2 according to the embodiment.

As described above, the first to sixth control target devices 51 to 56 have the same configuration except that the size of the motor M is different. For this reason, FIG. 5 selectively illustrates the first control target device 31 and the components necessary for the control of the first control target device 31, and the components related to the second to sixth control target devices 52 to 56. About is omitted. In addition, here, the same components as those shown in FIG. 2 are denoted by the same reference numerals as those shown in FIG.

As shown in FIG. 5, the motor control device 3 includes a motor power supply unit 37, a power conversion unit 31, a control unit 30, a control power supply unit 38, and a coupler CP. The control unit 30 includes a drive control unit 61, a specifying unit 62, a communication unit 63, and a communication control unit 66. The communication unit 63 includes a transmission unit 64 and a reception unit 65.

The drive control unit 61 compares the carrier signal ca and the voltage command values a, b, and c to generate the control signals Sa, Sb, and Sc described above, and the generated control signals Sa, Sb, and Sc are converted into a power conversion unit. 31 is a processing unit that outputs to 31. The drive control unit 61 outputs the voltage command values a, b, and c to the specifying unit 62 at a predetermined cycle.

Based on the periodic characteristics of the carrier signal ca, the specifying unit 62 performs a communication period in which noise due to at least the switching operation of the switching elements a1, a2, b1, b2, c1, and c2 is not superimposed within the period of the carrier signal ca. A processing unit to be identified.

In the specifying unit 62, the frequency of the carrier signal ca and the turn-on / off times of the switching elements a1, a2, b1, b2, c1, and c2 included in the inverter 31c are set in advance.

And the specific | specification part 62 is the voltage command value a, b, c input from the drive control part 61 with a predetermined period, the frequency of carrier signal ca, and each switching element a1, a2, b1, b2, c1, c2 The communication period is specified based on the turn ON / OFF time.

Here, with reference to FIG. 6, a procedure for the specifying unit 62 to specify the communication period will be described. FIG. 6 is an explanatory diagram for describing a procedure for specifying a communication period according to the embodiment. FIG. 6 shows, in order from the top, the waveform of the carrier signal ca, the waveform of the voltage command value a, the waveform of the control signal Sa, and the waveform of the switching noise n. The vertical axis of each waveform is a signal value, and the horizontal axis of each waveform is time t.

Further, the waveform of the carrier signal ca and the voltage command value a shown on the left side of the one-dot chain line shown in FIG. 6 are the waveform of the carrier signal ca and the waveform of the voltage command value a at the minute time t0 shown on the right side of the one-dot chain line. Is an enlarged version.

Here, during the period from time t1 to t2 and the period from time t5 to t6 shown in FIG. 6, the voltage command value a is larger than the signal value of the carrier signal ca, and during the period from time t2 to t5, A case where the value a is smaller than the signal value of the carrier signal ca will be described.

In such a case, the drive control unit 61 generates a control signal Sa that falls from the high level to the low level at time t2 and rises from the low level to the high level at time t5, and outputs the control signal Sa to the switching element a1. Therefore, the switching element a1 switches from ON to OFF at time 2 and switches from OFF to ON at time t5.

As a result, switching noise occurs during a period of time T3 from time t2 to time t3. The time T3 is substantially equal to the turn ON / OFF time of the switching element a1. Also, switching noise occurs at time t5.

Thus, the switching element a1 performs a switching operation at times t2 and t5 when the magnitude relationship between the voltage command value a and the signal value of the carrier signal ca is inverted. In other words, the switching element a1 performs a switching operation at times t2 and t5 at which the sine wave indicating the voltage command value a and the waveform of the carrier signal ca intersect. Such a switching operation is similarly performed in the other switching elements a2, b1, b2, c1, and c2.

Therefore, the switching noise is generated at the time t3 when the signal value of the carrier signal ca reaches the maximum value or the period before and after the times t1 and t6 when the signal value reaches the minimum value, for example, from the time t3 to t5 in the example shown in FIG. It can be seen that it does not occur at time T0.

The time T0 in which such switching noise does not occur periodically arrives every period from when the signal value of the carrier signal ca reaches the minimum value until it reaches the next minimum value. Alternatively, the time T0 when no switching noise occurs periodically arrives at every period from when the signal value of the carrier signal ca reaches the maximum value until it reaches the next maximum value.

Therefore, the specifying unit 62 specifies the time T0 in which the switching noise that sequentially arrives sequentially does not occur as a communication period in which the communication unit 30 periodically performs communication with the first control target device 51.

In this periodically arriving communication period, information is transmitted from the motor control device 3 to the first control target device 51, and information is transmitted from the first control target device 51 to the motor control device 3. There is a second communication period.

Further, the specifying unit 62 specifies the start point of the time T0 that sequentially arrives sequentially as the start point of the communication period. When the specifying unit 62 specifies the start point of the communication period, first, based on the frequency of the carrier signal ca, from the time t1 when the signal value of the carrier signal ca reaches a minimum value, then the signal value of the carrier signal ca The time T1 until time t4 when reaches the maximum value is calculated.

Further, the specifying unit 62 specifies the time t2 at which the switching element a1 performs the switching operation based on the signal value of the carrier signal ca and the voltage command value a. Subsequently, the specifying unit 62 calculates the time from time t4 to time t2.

Thereby, from the following equation (1), it is possible to calculate the time T4 from the time t1 when the signal value of the carrier signal ca reaches the minimum value to the time t3 when the switching noise of the next switching element a1 disappears. .

(Time T4) = (Time T1) − (Time T2) + (Time T3) (1)

More specifically, the specifying unit 62 uses the following equation (2) to determine the time until the time t3 when the switching noise of the switching element a1 that occurs next time t1 when the signal value of the carrier signal ca reaches the minimum value disappears. T4 is calculated.

T4 = 1 / (2 × fc) − {(1−η) / 2 × 1 / fc} / 2 + πtr (2)
fc: frequency η of the carrier signal ca: current voltage command values a, b, c when the maximum value of the voltage command values a, b, c is 1.
tr: Turn ON / OFF time of the switching elements a1, a2, b1, b2, c1, c2

The time T4 calculated in this way is the time from when the signal value of the carrier signal ca reaches the minimum value to the start point of the second communication period. Therefore, the specifying unit 62 outputs the time T4 to the communication control unit 66 as information related to the second communication period.

Returning to FIG. 5, the communication control unit 66 is a processing unit that controls the transmission timing of information by the transmission unit 64. Specifically, the communication control unit 66 outputs, for example, information related to the second communication period input from the specifying unit 62 and a communication start command to be described later to the transmission unit 64, thereby transmitting the first from the transmission unit 64. Information on the second communication period and a communication start command to be described later are transmitted to the control target device 51.

The transmission unit 64 is a processing unit that OFDM-modulates information to be transmitted to the first control target device 51 and transmits the information to the first control target device 51 via the coupler CP and the second cable 42.

The transmitting unit 64 transmits information related to the second communication period input from the communication control unit 66 to the first control target device 51 during the first communication period specified by the specifying unit 62. In addition, the transmission unit 64 transmits a transmission start command to the first control target device 51 in the first communication period that arrives first after transmitting the information related to the second communication period.

The receiving unit 65 is a processing unit that receives information indicating the state of the motor from the first control target device 51, OFDM-demodulates the received information, and outputs the information to the drive control unit 61. For example, when receiving the state information indicating the rotational position of the motor M from the first control target device 51, the receiving unit 65 outputs the received state information to the drive control unit 61. The communication timing of the communication unit 63 will be described later with reference to FIGS.

As described above, the communication unit 63 transmits to the control target device 5 at least in the first communication period that periodically arrives without noise caused by the switching operation of the switching elements a1, a2, b1, b2, c1, and c2. Send information. Thereby, the motor control device 3 can reduce the influence of noise on the control of the motor M.

On the other hand, the state detection device E included in the robot 2 includes a state detection unit 71, a communication unit 72, a timer unit 75, and a communication control unit 76. The communication unit 72 includes a reception unit 73 and a transmission unit 74. The state detection unit 71 is a processing unit that detects the rotational position of the motor M, and outputs the detected rotational position to the transmission unit 74 in the second communication period as information indicating the state of the motor M.

The receiving unit 73 is a processing unit that receives information from the motor control device 3 and performs OFDM demodulation in the first communication period. The receiving unit 73 receives information related to the second communication period described above, a transmission start command, and the like from the motor control device 3.

Then, when receiving the information related to the second communication period, the receiving unit 73 performs OFDM demodulation on the received information, and outputs to the time measuring unit 75 for setting. In addition, when receiving a transmission start command, the receiving unit 73 performs OFDM demodulation on the received information and outputs it to the time measuring unit 75.

The timer unit 75 is a timer provided with a memory that stores information (time T4 shown in FIG. 6) related to the second communication period set by the receiving unit 73. When the transmission start command is input from the receiving unit 73, the time measuring unit 75 measures the time T4 (see FIG. 6) described above based on the information regarding the second communication period that has already been set by the receiving unit 73 (see FIG. 6). Countdown). Then, when the timing of time T4 is completed, the timing unit 75 outputs information indicating that to the communication control unit 76.

The communication control unit 76 is a processing unit that controls the transmission timing of information by the transmission unit 74. Specifically, when information indicating that the time measurement at time T4 has been completed is input from the time measurement unit 75, the communication control unit 76 outputs information indicating that to the transmission unit 74, thereby The state information is transmitted from the transmission unit 74 to the motor control device 1.

The transmission unit 74 is a processing unit that OFDM-modulates information and transmits it to the motor control device 3 during the second communication period in accordance with communication timing control by the communication control unit 76. When the information indicating that the time counting by the time measuring unit 75 is completed is input from the communication control unit 76, the transmission unit 74 performs OFDM modulation on the state information input from the state detection unit 71 and performs motor control. 3 to send. The communication timing of the communication unit 72 will be described later with reference to FIGS.

As described above, the communication unit 72 transmits information to the motor control device 3 at least in the second communication period in which noise due to the switching operation of the switching elements a1, a2, b1, b2, c1, and c2 is not superimposed. Thereby, the motor control device 3 can reduce the influence of noise on the control of the motor M.

Next, communication timings performed by the communication unit 63 of the motor control device 3 and the communication unit 72 of the control target device 5 will be described with reference to FIGS. FIG. 7 is a sequence diagram illustrating communication performed in the motor control system 1 according to the embodiment, and FIG. 8 is an explanatory diagram illustrating timing of communication performed in the motor control system 1 according to the embodiment.

As shown in FIG. 7, the motor control device 3 first has information on the second communication period (time T4 shown in FIG. 6) in the period from the start point to the end point of the first communication period that comes first. Are transmitted to all the control target devices 5 during the first communication period (step S1). The first control target device 51 receives information related to the second communication period (step S2).

Subsequently, the second control target device 52 receives information related to the second communication period (step S3). In this way, the information regarding the second communication period is sequentially received by all the control target devices 5. Each control target device 5 sets the received information related to the second communication period in the timer unit 75.

Subsequently, the motor control device 3 sends a transmission start command to the first control target device 51 during a period from the start point to the end point of the first communication period that arrives first after transmitting the information related to the second communication period. (Step S4). When receiving the transmission start command, the first control target device 51 starts measuring time T4 (step S5).

And the 1st control object apparatus 51 is the state of the motor M in the period from the start point of the 2nd communication period which arrives first after receiving a transmission start command, ie, the time point when time-measurement was completed. Information is transmitted to the motor control device 3 (step S6). Subsequently, after receiving the state information from the first control target device 51, the motor control device 3 sends a transmission start command to the second control in a period from the start point to the end point of the first communication period that comes first. It transmits to the object apparatus 52 (step S7).

When receiving the transmission start command, the second control target device 52 starts measuring time T4 (step S8). Then, the second control target device 52 performs the state of the motor M at the time from when the time measurement is completed, that is, from the start point to the end point of the second communication period that arrives first after receiving the transmission start command. Information is transmitted to the motor control device 3 (step S9).

In the motor control system 1, transmission / reception of information on the second communication period, transmission / reception of a transmission start command, and the transmission / reception start command are sequentially performed between the motor control device 3 and the third to sixth control target devices 53-56. Status information is transmitted and received.

As a result, for example, as shown in FIG. 8, the noise caused by the switching operation of at least the switching elements a1, a2, b1, b2, c1, and c2 that sequentially arrive at the timing synchronized with the cycle of the carrier signal ca is not superimposed. Information is communicated between the motor control device 3 and the first to sixth control target devices 51 to 56 in the first communication period and the second communication period (time T0).

8 indicates the timing at which information is transmitted from the motor control device 3 to each control target device 5, and the pulse shown in white indicates the pulse from each control target device 5 to the motor control device 3. The timing at which information is transmitted is shown.

Note that times t10, t12, t14, t16, t18, t20, and t22 shown in FIG. 8 are times corresponding to the time t3 shown in FIG. That is, the time when the time T4 has elapsed after the signal value of the carrier signal ca reaches the minimum value. Also, times t11, t13, t15, t17, t19, and t21 shown in FIG. 8 are times when time T4 has elapsed since the signal value of the carrier signal ca reached the maximum value. 8 is the same as the time T4 shown in FIG. The time T0 shown in FIG. 8 is the same time as the time T0 shown in FIG.

As shown in FIG. 8, when the first first communication period arrives at time t10, information related to the second communication period is transmitted from the motor control device 3 to all the control target devices 5, and at time t11, the next When the first communication period comes, a transmission start command is transmitted from the motor control device 3 to the first control target device 51. Thereafter, when the second communication period comes at time t12 when the time T4 has elapsed, the state information of the motor M is transmitted from the first control target device 51 to the motor control device 3.

Subsequently, when the first communication period arrives at time t13, a transmission start command is transmitted from the motor control device 3 to the second control target device 52. Thereafter, when the second communication period comes at time t14 when the time T4 has elapsed, the state information of the motor M is transmitted from the second control target device 52 to the motor control device 3.

Subsequently, when the first communication period arrives at time t15, a transmission start command is transmitted from the motor control device 3 to the third control target device 53. Thereafter, when the second communication period arrives at time t <b> 16 when the time T <b> 4 has elapsed, the state information of the motor M is transmitted from the third control target device 53 to the motor control device 3.

Subsequently, when the first communication period arrives at time t17, a transmission start command is transmitted from the motor control device 3 to the fourth control target device 54. Thereafter, when the second communication period comes at time t18 when the time T4 has elapsed, the state information of the motor M is transmitted from the third control target device 53 to the motor control device 3.

Subsequently, when the first communication period arrives at time t19, a transmission start command is transmitted from the motor control device 3 to the fifth control target device 55. Thereafter, when the second communication period comes at time t20 when the time T4 has elapsed, the state information of the motor M is transmitted from the fifth control target device 55 to the motor control device 3.

Subsequently, when the first communication period arrives at time t21, a transmission start command is transmitted from the motor control device 3 to the sixth control target device 56. Thereafter, when the second communication period comes at time t22 when the time T4 has elapsed, the state information of the motor M is transmitted from the sixth control target device 56 to the motor control device 3. In the motor control system 1, the same communication as that performed at times t10 to t22 is repeatedly executed until the amount of change in the voltage command values a, b, and c becomes equal to or greater than a predetermined threshold value.

Thus, the motor control system 1 can perform communication between the motor control device 3 and the control target device 5 for each cycle of the carrier signal ca without stopping the periodic switching operation of the inverter 31c. Therefore, according to the motor control system 1, it is possible to improve the drive control performance for the motor M while reducing the influence of switching noise.

Next, the process executed by the control unit 30 of the motor control device 3 will be described with reference to FIG. FIG. 9 is a flowchart illustrating processing executed by the control unit 30 of the motor control device 3 according to the embodiment.

As shown in FIG. 9, in the control unit 30, first, the specifying unit 62 specifies a communication period based on the periodic characteristics related to the signal value of the carrier signal ca (step S <b> 101). In the communication period, as described above, the first communication period in which information is transmitted from the motor control device 3 to the control target device 5 and the second communication in which information is transmitted from the control target device 5 to the motor control device 3. There is a period. Then, the specifying unit 62 outputs information regarding the specified communication period to the communication unit 63 of the control unit 30.

Subsequently, the communication control unit 66 of the control unit 30 determines whether or not it is the first communication period (step S102). If the communication control unit 66 determines that it is not the first communication period (No in step S102), the communication control unit 66 repeats the determination in step S102 until the first communication period is reached.

Further, when the communication control unit 66 determines that it is the first communication period (Yes in step S102), all the control target devices 5 are set at the start point t10 of the first communication period specified by the specifying unit 62. Information on the second communication period is transmitted to the transmitter 64 (step S103). The information related to the second communication period transmitted here is information indicating the time T4 described above.

The specifying unit 62 may be configured to specify each time point when the signal value of the carrier signal ca reaches the maximum value or the minimum value as the start point of the first communication period or the second communication period. With this configuration, the specifying unit 62 can specify the start point of the first communication period or the second communication period by a simpler specifying algorithm.

Thereafter, the communication control unit 66 determines again whether or not it is the first communication period (step S104). That is, the communication control unit 66 determines whether or not it is the start point of the first communication period that comes first after the first communication period in which the information related to the second communication period is transmitted. And when it determines with the communication control part 66 not being a 1st communication period (step S104, No), it repeats the determination of step S104 until it becomes a 1st communication period.

Further, when the communication control unit 66 determines that it is the first communication period (step S104, Yes), the transmission unit 64 sends a transmission start command to the start point t11 of the first communication period. It transmits to the control object apparatus 5 (step S105). Thereafter, the receiving unit 65 of the control unit 30 receives the state information indicating the state of the motor M from the control target device 5 that is the transmission destination of the transmission start command at the start point t12 of the second communication period that comes next. It is determined whether or not (step S106).

And when the receiving part 65 determines with not receiving status information (step S106, No), it repeats determination of step S106 until it receives status information. If the receiving unit 65 determines that the state information has been received (step S106, Yes), the process proceeds to step S107.

In step S107, the communication control unit 66 of the control unit 30 determines whether a transmission start command has been transmitted to all the control target devices 5. If the communication control unit 66 determines that the transmission start command has not been transmitted to all the control target devices 5 (No in step S107), the communication control unit 66 moves the process to step S105, and starts the first communication period that comes next. At point t 13, the transmission start command is transmitted to the untransmitted control target device 5 by the transmission unit 64.

Further, when the communication control unit 66 determines that the transmission start command has been transmitted to all the control target devices 5 (step S107, Yes), the process proceeds to step S108. In step S108, the drive control unit 61 of the control unit 30 determines whether or not the change amount of the voltage command value is equal to or greater than a threshold value.

And when it determines with the variation | change_quantity of a voltage command value being more than a threshold value by the drive control part 61 (step S108, Yes), the control part 30 complete | finishes a process and starts a process again from step S101. .

When the drive control unit 61 determines that the amount of change in the voltage command value is less than the threshold (No in step S108), the control unit 30 moves the process to step S104, and the amount of change in the voltage command value is The processing of steps S104 to S108 is repeated in a period less than the threshold value.

Next, processing executed by the state detection device E according to the embodiment will be described with reference to FIG. FIG. 10 is a flowchart illustrating processing executed by the state detection device according to the embodiment. When the drive control of the motor M is performed, the state detection device E repeatedly executes the process shown in FIG.

In the state detection device E, the state detection unit 71 always detects information indicating the state of the motor M at a predetermined cycle during the period in which the process shown in FIG. 10 is being performed, and the state detection device E includes the detection result. The data is output to the transmission unit 74 in the communication unit 72.

And when the drive control of the motor M is started, the receiving part 73 of the state detection apparatus E determines whether the information regarding the 2nd communication period was received from the motor control apparatus 3 (step S201). And when the receiving part 73 determines with not receiving the information regarding a 2nd communication period (step S201, No), it moves a process to step S203.

In addition, when it is determined that the information related to the second communication period has been received (Yes in step S201), the receiving unit 73 outputs the received information related to the second communication period to the time measuring unit 75 and sets the information (step S202). ).

Subsequently, the receiving unit 73 determines whether or not a transmission start command is received from the motor control device 3 (step S203). And when the receiving part 73 determines with not receiving a transmission start command (step S203, No), it moves a process to step S201.

If the receiving unit 73 determines that a transmission start command has been received (step S203, Yes), the process proceeds to step S204. In step S204, the time measuring unit 75 of the state detection device E starts to time (count down) the time T4 set in step S202.

Thereafter, the time measuring unit 75 determines whether or not the time measurement is completed (step S205). Then, when it is determined that the time measurement is not completed (No at Step S205), the time measuring unit 75 repeats the determination at Step S205 until the time measurement is completed.

In addition, when it is determined that the timing has been completed (step S205, Yes), the timing unit 75 moves the process to step S206. In step S206, the communication control unit 76 of the state detection device E causes the transmission unit 74 to use the state detection unit 71 at the start point of the second communication period (for example, time t12, t14, t16, t18, t20, t22). State information indicating the state of the motor M input from is transmitted to the motor control device 3 and the process is terminated. Then, the state detection apparatus E starts a process again from step S201.

As described above, the motor control system according to the embodiment includes a control target device including a motor and a communication unit, a motor control device that performs drive control of the motor based on a carrier signal whose signal value periodically changes, and including.

Then, the motor control device includes a communication unit that communicates information with the communication unit of the control target device, and a communication period that causes the communication unit of the motor control device to periodically communicate information. And a specifying unit that specifies based on a periodic characteristic of the value.

Such a motor control device does not stop the drive control of the motor and based on the cycle of the carrier signal, at least during a period in which noise due to the operation of the switching element for motor drive control is not superimposed, Communication can be performed. Therefore, according to the motor control system, it is possible to improve the drive control performance for the motor while reducing the influence of the switching noise.

In addition, when the motor control device according to the embodiment performs drive control of the motor by the carrier comparison method, for example, switching for controlling the operation of the motor at the timing when the signal value of the carrier signal reaches the maximum value and the minimum value. No action is taken.

Therefore, the specifying unit according to the embodiment specifies the communication period based on periodic characteristics in which the signal value of the carrier signal periodically reaches a maximum value and a minimum value. Thereby, the specific unit sets an appropriate communication period in which at least noise caused by the operation of the switching element for motor drive control is not superimposed by using the timing at which the signal value of the carrier signal reaches the maximum value and the minimum value as a reference. Can be identified.

In addition, when the motor control device performs motor drive control by, for example, the carrier comparison method, the switching operation for performing motor drive control is performed at the timing when the voltage command value for the motor and the signal value of the carrier signal match. Done.

Therefore, the specifying unit according to the embodiment specifies the start timing of the communication period based on the timing at which the voltage command value for the motor matches the signal value of the carrier signal. Thereby, the specifying unit can specify the start timing of the period in which noise is not superimposed from the timing at which the voltage command value for the motor matches the signal value of the carrier signal by a relatively simple process.

Also, the specifying unit according to the embodiment specifies the start timing of the communication period based on the switching characteristics of the switching element that is provided in the motor control device and controls the power supplied to the motor. Thereby, the specific | specification part can estimate more correctly the start timing of the communication period in which noise is not superimposed according to the switching characteristic of a switching element.

In addition, the communication unit of the motor control device according to the embodiment transmits information to the communication unit of the control target device during the first communication period among the communication periods that come periodically. Thereby, at least from the motor control device to the control target device, it is possible to transmit information on which noise due to the operation of the motor drive control switching element is not superimposed.

In addition, the communication unit of the motor control device according to the embodiment includes information related to a second communication period that causes information to be transmitted from the communication unit of the control target device to the communication unit of the motor control device among the communication periods that periodically arrive. It transmits to the communication part of a control object apparatus in the 1st communication period. And the communication part of a control object apparatus transmits information to the communication part of a motor control apparatus in a 2nd communication period based on the information regarding the 2nd communication period received from the communication part of a motor control apparatus.

Accordingly, in the motor control system, bidirectional information communication performed between the motor control device and the control target device can be performed at least in a communication period in which noise due to the switching operation of the switching element for motor drive control is not superimposed. .

Further, the control target device according to the embodiment includes a state detection unit that detects the state of the motor. And the communication part of a control object apparatus transmits the information which shows the state of the motor detected by the state detection part in a 2nd communication period. In addition, the motor control device performs drive control of the motor based on information indicating the state of the motor received from the communication unit of the control target device.

Thereby, the motor control system according to the embodiment can improve the feedback drive control performance of the motor according to the state of the motor while reducing the influence of the switching noise.

In the above-described embodiment, the case where the same time is transmitted as information related to the second communication period from the motor control device to all the control target devices has been described. However, the second time to be transmitted to each control target device. The information regarding the communication period may not be the same time.

For example, if the transmission path length of information from the motor control device to each control target device is not the same, the control target device having a long transmission path length causes information transmission delay, so the information is transmitted from the motor control device. The time until reception is longer than that of the control target apparatus having a short transmission path length.

In such a case, the motor control device shortens the transmission time as information related to the second communication period by the transmission delay as the control target device has a longer transmission path length. Thereby, each control object apparatus can transmit information to a motor control apparatus in the exact 2nd communication period, even if there is a difference in transmission path length.

Further, when the same time is transmitted as information related to the second communication period from the motor control device to all the control target devices, each control target device transmits from the time received as information related to the second communication period. A configuration may be used in which the time obtained by subtracting the delay is counted. Thereby, each control object apparatus can transmit information to a motor control apparatus in the exact 2nd communication period, even if there is a difference in transmission path length.

In addition, when the state detection unit detects a plurality of types of states from the motor, the motor control system according to the embodiment specifies the communication for transmitting information from the motor control device to the control target device by the specifying unit. The communication that is performed during one communication period and transmits information from the control target apparatus to the motor control apparatus may be performed during an arbitrary period.

In such a case, the motor control device transmits, for example, information specifying the type of state of the motor to be transmitted from the control target device to the motor control device to the control target device in the first communication period specified by the specifying unit. . Thereby, in the motor control system according to the embodiment, at least information to be transmitted to the control target device can be transmitted from the motor control device to the control target device in an accurate state in which the influence of noise is reduced.

Further, the motor control device according to the embodiment does not necessarily have to perform feedback control on the motor, and may perform open loop control on the motor.

For example, when the motor control device performs open loop control and the control target device includes a display unit that displays information related to motor drive control as an integral or separate unit, the motor control device displays information to be displayed on the display unit. Is transmitted to the controlled device during the first communication period, but it is not necessary to receive information from the controlled device.

For this reason, in such a configuration, the motor control device includes a transmission unit that transmits information to the control target device in the first communication period specified by the specification unit, and the control target device receives information from the motor control device. What is necessary is just to provide the receiving part. According to such a motor control system, the receiving unit of the motor control device and the transmission unit of the control device can be omitted, and the system can be simplified.

In the above-described embodiment, the case where the motor control device generates a control signal for driving the motor based on the carrier comparison method has been described. However, the method for generating the control signal is not limited to this.

That is, if the motor control device generates a control signal for driving the motor based on the carrier signal, for example, it generates a control signal for driving the motor based on another method such as a so-called space vector method. It may be.

In the above-described embodiment, the case where each control target device 5 is provided in each arm of the robot 2 has been described as an example. However, in the motor control system according to the embodiment, the base unit 20 is the first control target device. 51, the first arm 21 corresponds to the second control target device 52, the second arm 22 corresponds to the third control target device 53, the third arm 23 corresponds to the fourth control target device 54, The fourth arm 24 may correspond to the fifth control target device 55, and the fifth arm 25 may correspond to the sixth control target device 56. Further, the control target device controlled by the motor control device may be the entire robot.

Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1 Motor control apparatus 2 Robot 3 Motor control apparatus 31-36 Power conversion part 61 Drive control part 62

Identification part

63,72 Communication part 64,74

Transmission part

65,73 Reception part 71 State detection part 75

Time measurement part

66,76 Communication control Part M Motor 5, 51 to 56 Control target device E Status detection device

Claims

A control target device comprising a motor and a communication unit;
A motor control device that performs drive control of the motor based on a carrier signal whose signal value periodically changes, and
The motor control device
A communication unit that communicates information with the communication unit of the control target device;
A motor control system comprising: a specifying unit that specifies a communication period for causing the communication unit of the motor control device to communicate the information based on a periodic characteristic of the signal value.
The specific part is:
The motor control system according to claim 1, wherein the communication period is specified based on the periodic characteristic in which a signal value of the carrier signal periodically reaches an extreme value.
The specific part is:
The motor control system according to claim 1 or 2, wherein a start timing of the communication period is specified based on a timing at which a voltage command value for the motor matches a signal value of the carrier signal.
The motor control device
A switching element for controlling the power supplied to the motor;
The specific part is:
The motor control system according to any one of claims 1 to 3, wherein a start timing of the communication period is specified based on a switching characteristic of the switching element.
The motor control device
In the first communication period in which information is transmitted from the communication unit of the motor control device to the communication unit of the control target device during the communication period, the information to the control target device is transmitted to the communication unit of the motor control device. The motor control system according to any one of claims 1 to 4, further comprising a communication control unit for transmitting.
The communication control unit of the motor control device is
Of the communication period, information related to a second communication period for transmitting information from the communication unit of the control target device to the communication unit of the motor control device is transmitted to the communication unit of the motor control device during the first communication period. Send to
The device to be controlled is
And a communication control unit that transmits information to the motor control device to the communication unit of the control target device based on information on the second communication period received from the communication unit of the motor control device. The motor control system according to claim 5.
The device to be controlled is
A state detection unit for detecting the state of the motor;
The communication control unit of the device to be controlled is
Information indicating the state of the motor detected by the state detection unit is transmitted to the communication unit of the motor control device by the communication unit of the control target device during the second communication period,
The motor control device
The motor control system according to claim 6, wherein the drive control is performed based on information indicating a state of the motor received from a communication unit of the control target device.
A drive control unit that performs drive control of a motor included in the control target device based on a carrier signal whose signal value periodically changes;
A communication unit for communicating information with the control target device;
A motor control device comprising: a specifying unit that specifies a communication period for causing the communication unit of the motor control device to communicate the information based on a periodic characteristic of the signal value.
Based on a carrier signal whose signal value periodically changes, a drive control unit that performs drive control of a motor included in the control target device, a communication unit that communicates information with the control target device, and the communication unit A communication unit that performs communication of the information with a motor control device including a specifying unit that specifies a communication period in which the communication of the information is performed based on a periodic characteristic of the signal value. Control target device.
The motor control device performs drive control of the motor included in the control target device based on a carrier signal whose signal value periodically changes; and
The motor control device performs communication of information with the control target device;
The motor control device includes: specifying a communication period for causing the communication unit of the motor control device to communicate the information based on a periodic characteristic of the signal value.