JP7815866B2 - Control device - Google Patents

Description

The present invention relates to a control device.

Vehicle steering devices equipped with electronic control devices are known. For example, in Patent Document 1, a CAN communication signal using an in-vehicle network is input to the electronic control device.

Patent No. 5125086

In Patent Document 1, a determination is made as to whether the start-up signal input to the CAN transceiver truly indicates that the device should be started. However, if the start-up signal cannot be received due to a communication abnormality, the microcomputer cannot be started.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a control device that can appropriately switch the startup state of a microcomputer even when a communication abnormality occurs.

The control device of the present invention includes a microcomputer (40) and an activation determination circuit (30). The microcomputer performs arithmetic processing related to drive control of a motor (80). The activation determination circuit can switch the microcomputer from a sleep state to a wake-up state in response to a plurality of activation signals corresponding to the operating state of the vehicle. The activation determination circuit switches the microcomputer from the sleep state to the wake-up state when at least one of the plurality of activation signals becomes a trigger state related to activation of the microcomputer.
The activation signal includes a signal from the vehicle communication network (6, 7) and a signal from a rotation angle sensor (25) that detects the rotation state of the motor and is constantly powered by the battery (5) so that at least a portion of the detection operation can continue even when the vehicle switch is turned off. The motor outputs torque required for steering. When a signal from the vehicle communication network can be acquired, the microcomputer switches from a sleep state to a wake-up state based on the signal from the vehicle communication network, allowing the microcomputer to perform calculations related to motor drive control. The microcomputer determines whether an assist permission signal related to steering assist transmitted from the vehicle communication network is on, and starts steering assist control if the assist permission signal is on. When a signal from the vehicle communication network is not acquired and it is detected that the operation state of the rotation angle sensor has changed, the microcomputer switches from a sleep state to a wake-up state so that the microcomputer can perform calculations related to motor drive control and starts steering assist control without waiting for the assist permission signal. This allows the microcomputer's activation state to be appropriately switched even during a communication abnormality.

1 is a schematic configuration diagram showing a steering system according to a first embodiment. FIG. FIG. 2 is a block diagram showing an ECU according to the first embodiment. 5 is a time chart illustrating switching of a microcomputer startup state when CAN communication is normal in the first embodiment. 5 is a time chart illustrating switching of a microcomputer startup state when CAN communication is abnormal in the first embodiment. 4 is a flowchart illustrating a microcomputer startup process according to the first embodiment. 5 is a flowchart illustrating a process during a microcomputer sleep state according to the first embodiment. FIG. 10 is a block diagram showing an ECU according to a second embodiment. FIG. 10 is a block diagram showing an ECU according to a third embodiment. 10 is a flowchart illustrating a process during a microcomputer sleep state according to a third embodiment.

(First embodiment)
A control device according to the present invention will be described below with reference to the drawings. In the following, substantially identical components in multiple embodiments are assigned the same reference numerals, and description thereof will be omitted. A control device according to a first embodiment is shown in FIGS. 1 to 6. As shown in FIG. 1, a drive unit 1 includes a motor 80 and an ECU 10 as a control device, and is applied to an electric power steering device 8, which is a steering device for assisting the steering operation of a vehicle. FIG. 1 shows the overall configuration of a steering system 90 including the electric power steering device 8. The steering system 90 includes a steering wheel 91, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, and the electric power steering device 8, which are steering members.

The steering wheel 91 is connected to a steering shaft 92. A torque sensor 93 that detects steering torque is provided on the steering shaft 92. A pinion gear 96 is provided at the tip of the steering shaft 92. The pinion gear 96 meshes with a rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like.

When the driver turns the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into linear motion of the rack shaft 97 by the pinion gear 96. A pair of wheels 98 are steered to an angle that corresponds to the amount of displacement of the rack shaft 97.

The electric power steering device 8 includes a drive unit 1 and a reduction gear 89 as a power transmission unit that reduces the rotation of the motor 80 and transmits it to the rack shaft 97. The electric power steering device 8 of this embodiment is a so-called "rack assist type," but it may also be a so-called "column assist type" that transmits the rotation of the motor 80 to the steering shaft 92.

The motor 80 is a three-phase brushless motor. The motor 80 outputs some or all of the torque required for steering, and is driven by power supplied from a battery 5 (not shown), causing the reduction gear 89 to rotate forward and reverse. The drive unit 1 is a so-called "mechanical-electrical integrated type" in which the ECU 10 is integrally provided on one side of the motor 80 in the axial direction, but the mechanical and electrical components may also be separate.

The ECU 10 has connectors 11 and 12. The connector 11 is connected to the battery 5 and the vehicle communication network 6. In this embodiment, the vehicle communication network 6 is a CAN (Controller Area Network), but it may be of a standard other than CAN. Hereinafter, the vehicle communication network 6 will be referred to simply as "CAN" where appropriate. The connector 12 is connected to the torque sensor 93.

As shown in FIG. 2, the ECU 10 includes a normal power supply circuit 21, a low-voltage power supply circuit 22, a rotation angle sensor 25, a CAN driver 28, a start-up determination circuit 30, and a microcomputer 40. In FIG. 2, the connection terminal with the battery 5 is labeled "+B."

The normal power supply circuit 21 is connected to the battery 5 and supplies power to the microcomputer 40 when activated. The low-voltage power supply circuit 22 includes, for example, a regulator. The low-voltage power supply circuit 22 is constantly powered by the battery 5 and supplies power to the rotation angle sensor 25 and CAN driver 28 at a voltage sufficient to drive connected electronic components.

The rotation angle sensor 25 detects the rotational position of the motor 80 and has at least two drive modes: normal mode and power saving mode. In normal mode, for example, when a vehicle switch (not shown) (hereinafter referred to as "IG") is turned on, power is supplied via the IG, and the rotation angle of the motor 80 is detected with relatively high accuracy. In power saving mode, for example, when the IG is turned off, the number of rotations of the motor 80 is detected using power supplied via the low-voltage power supply circuit 22.

When the IG switches from off to on under normal conditions, the rotation angle sensor 25 switches from power saving mode to normal mode in response to a command from the microcomputer 40. In power saving mode, the sensor is also configured to switch from power saving mode to normal mode if, for example, rotation of the motor 80 due to steering of the steering wheel 91 is detected.

The CAN driver 28 is connected to the CAN bus and acquires various information from the vehicle communication network 6. The activation determination circuit 30 is connected to the CAN driver 28 and the rotation angle sensor 25, and outputs a signal related to switching the activation state of the normal power supply circuit 21.

The microcomputer 40 performs various calculations related to the drive control of the motor 80. The microcomputer 40 is also configured to be able to send and receive various information to and from the vehicle communication network 6 via the CAN driver 28. The microcomputer 40 switches from a sleep state to a wake-up state when power is supplied from the normal power supply circuit 21, and switches from the wake-up state to a sleep state when the power supply from the normal power supply circuit 21 is interrupted.

The startup process of the microcomputer 40 when CAN communication is normal will be explained based on the time chart in Figure 3. In Figure 3, the horizontal axis represents the common time axis, and from the top, the diagram shows the CAN signal, steering assist permission signal, trigger output from the CAN driver 28, trigger output from the startup determination circuit 30, the on/off state of the normal power supply circuit 21, the startup state of the microcomputer 40, and the steering assist state. In Figures 3 and 4, signal transmission is indicated by dashed arrows.

In this embodiment, to reduce current consumption, the microcomputer 40 is woken up starting from CAN communication. When the CAN signal is turned on at time x10, the trigger output of the CAN driver 28 and the trigger output of the activation determination circuit 30 are turned on, and the normal power supply circuit 21 is turned on. When the normal power supply circuit 21 is turned on, power is supplied to the microcomputer 40, and the microcomputer 40 switches from a sleep state to a wake-up state, becoming able to perform various calculation processes. Furthermore, when the microcomputer 40 receives a steering assist permission signal from the vehicle communication network 6 at time x11, steering assist is permitted at time x12.

When the steering assist permission signal and the CAN signal are both turned off, the microcontroller 40 switches the steering assist state from permitted to prohibited. That is, when the steering assist permission signal is turned off at time x13 and the CAN signal is turned off at time x14, the microcontroller 40 switches the steering assist state from permitted to prohibited at time x15. After switching the steering assist to the prohibited state, the microcontroller 40 sends a shutdown request to the activation determination circuit 30, which sequentially turns off the activation determination circuit 30 and the normal power supply circuit 21. When the normal power supply circuit 21 is turned off, the power supply to the microcontroller 40 is cut off, and the microcontroller 40 switches from the wake-up state to the sleep state.

If an abnormality occurs in which a signal cannot be received from the vehicle communication network 6, the microcomputer 40 cannot be started using the above logic. Therefore, in this embodiment, the rotation angle sensor 25 is constantly powered and continues to operate even when the IG is off. Therefore, if a signal cannot be received from the vehicle communication network 6, the signal from the rotation angle sensor 25 is used to start the microcomputer 40 without increasing the number of terminals, etc.

The microcomputer startup process when a signal cannot be received from the vehicle communication network 6 will be explained based on the time chart in Figure 4. In Figure 4, the horizontal axis represents the common time axis, and from the top, the diagram shows the CAN signal, the drive mode of the rotation angle sensor 25, the trigger output from the startup determination circuit 30, the on/off state of the normal power supply circuit 21, the startup state of the microcomputer 40, and the steering assist state.

In Figure 4, because a signal cannot be received from the vehicle communication network 6, the CAN signal remains off. Therefore, the microcomputer 40 remains off even when the IG is turned on. Also, when the IG is off, the rotation angle sensor 25 monitors the rotation state of the motor 80 in power-saving mode. When the IG is off, the steering wheel 91 is locked, so there is a high probability that the motor 80 will not rotate.

At time x20 after the IG is turned on, when the driver turns the steering wheel 91 and the motor 80 rotates, causing a change in signal, the rotation angle sensor 25 switches the drive mode from power saving mode to normal mode. In this embodiment, the rotation angle sensor 25 is connected to the activation determination circuit 30, and when the activation determination circuit 30 detects that the rotation angle sensor 25 has switched from power saving mode to normal mode, the trigger output is turned on and the normal power supply circuit 21 is turned on.

When the normal power supply circuit 21 is turned on, power is supplied to the microcomputer 40, which switches from a sleep state to a wake-up state, enabling it to perform various calculation processes. Furthermore, once the normal power supply circuit 21 is turned on, it remains on until a shutdown request is received.

In this embodiment, the activation determination circuit 30 is configured, for example, with an OR circuit, and its trigger output is turned on if the trigger signal from the CAN driver 28 is on or if the drive mode of the rotation angle sensor 25 is normal mode. If CAN communication is normal, for example while the IG is on, the trigger signal remains on, and the trigger output of the activation determination circuit 30 also remains on. On the other hand, if CAN communication is interrupted, the trigger output state of the activation determination circuit 30 switches depending on the drive state of the rotation angle sensor 25.

Based on the drive state of the rotation angle sensor 25, if the rotation angle sensor 25 enters the power saving mode at time x22 and the power saving mode continues for the non-steering determination time Xth, the microcomputer 40 determines that the IG is off and prohibits steering assist. The non-steering determination time Xth is set according to the time from the non-steering state during which the IG can be considered to be off. After switching the steering assist to the prohibited state, the microcomputer 40 sends a shut-off request to the normal power supply circuit 21, which turns off the normal power supply circuit 21 at time x24. When the normal power supply circuit 21 is turned off, the power supply to the microcomputer 40 is cut off, and the microcomputer 40 switches from the wake-up state to the sleep state.

The microcomputer startup process will be explained based on the flowchart in Figure 5. This process is executed when the microcomputer 40 enters a wake-up state. In S101, the microcomputer 40 determines whether or not a CAN signal has been received. If it is determined that a CAN signal has been received (S101: YES), the process proceeds to S103. If it is determined that a CAN signal has not been received (S101: NO), the process proceeds to S102, where it is determined that there is an abnormality in CAN communication. The process then proceeds to S104, where assist control is started without waiting for an assist permission signal.

In S103, the microcomputer 40 determines whether the assist permission signal from CAN communication has been turned on. If it is determined that the assist permission signal has not been turned on (S103: NO), this determination process is repeated. If it is determined that the assist permission signal has been turned on (S103: YES), the process proceeds to S104, where assist control is initiated.

The microcomputer sleep processing will be explained based on the flowchart in Figure 6. This processing is executed at a predetermined interval while the microcomputer 40 is running. In S201, the microcomputer 40 determines whether CAN communication is normal. If it is determined that CAN communication is abnormal (S201: NO), the process proceeds to S206. If it is determined that CAN communication is normal (S201: YES), the process proceeds to S202.

In S202, the microcomputer 40 determines whether the assist permission signal from CAN communication has been turned off. If it is determined that the assist permission signal is on (S202: NO), the processing from S203 onwards is skipped. If it is determined that the assist permission signal is off (S202: YES), the processing proceeds to S203.

In S203, the microcomputer 40 determines whether CAN communication has stopped. If it is determined that CAN communication has not stopped (S203: NO), the process returns to S202. If it is determined that CAN communication has stopped (S203: YES), the process proceeds to S204, where assist control is stopped.

In S205, the microcomputer 40 sends a shutdown request to the activation determination circuit 30. When the activation determination circuit 30 shuts down in response to the shutdown request, the normal power supply circuit 21 turns off, cutting off power supply to the microcomputer 40. This causes the microcomputer 40 to switch to a sleep state.

If it is determined that CAN communication is abnormal (S201: NO), the microcomputer 40 proceeds to S206, where it determines whether the power-saving state of the rotation angle sensor 25 has continued for the non-steering determination time Xth. If it is determined that the rotation angle sensor 25 is in a normal state or that the duration of the power-saving state is less than the non-steering determination time Xth (S206: NO), the microcomputer 40 skips S207. If it is determined that the power-saving state of the rotation angle sensor 25 has continued for the non-steering determination time Xth (S206: YES), the microcomputer 40 proceeds to S207 and sends a shutdown request to the normal power supply circuit 21. When the normal power supply circuit 21 is turned off in response to the shutdown request, power supply to the microcomputer 40 is cut off. This causes the microcomputer 40 to switch to a sleep state.

As described above, the ECU 10 includes a microcomputer 40 and an activation determination circuit 30. The microcomputer 40 performs calculations related to the drive control of the motor 80. The activation determination circuit 30 can switch the microcomputer 40 from a sleep state to a wake-up state in response to multiple activation signals that correspond to the operating state of the vehicle. The activation determination circuit 30 switches the microcomputer 40 from a sleep state to a wake-up state when at least one of the multiple activation signals becomes a trigger state related to the activation of the microcomputer 40.

Here, the wake-up state is a state in which power is supplied from the normal power supply circuit 21 and various calculations related to steering assist, etc. can be performed, and the sleep state is a state in which power is not supplied from the normal power supply circuit 21 and various calculations related to steering assist, etc. cannot be performed. As a result, even if an abnormality occurs in some of the activation signals, the microcomputer 40 can be appropriately switched from the sleep state to the wake-up state as long as at least one activation signal is normal.

In this embodiment, the startup signal includes a signal from the vehicle communication network 6 and a signal from the rotation angle sensor 25. The rotation angle sensor 25 detects the rotation state of the motor 80, and by being constantly powered by the battery 5, it is able to continue at least some of its detection operations even while the vehicle switch is off. As a result, in a configuration in which the microcomputer 40 is woken up by a startup command from the vehicle communication network 6, even if an abnormality occurs in communication from the vehicle communication network 6, the microcomputer 40 can be appropriately woken up using information from the rotation angle sensor 25, which is constantly powered.

The motor 80 outputs the torque required for steering. If the activation command can be received from the vehicle communication network 6, the activation determination circuit 30 switches the microcomputer 40 from a sleep state to a wake-up state based on the activation command. If the activation command is not received from the vehicle communication network 6 and the activation determination circuit 30 detects that the operating state of the rotation angle sensor 25 has changed, the activation determination circuit 30 switches the microcomputer 40 from a sleep state to a wake-up state. In particular, if the activation determination circuit 30 detects that the drive mode of the rotation angle sensor 25 has changed from a power-saving mode to a normal mode, the activation determination circuit 30 switches the microcomputer 40 to a wake-up state.

In this embodiment, the motor 80 is applied to the electric power steering device 8, and when the driver steers the steering wheel 91, the motor 80 rotates, switching the operating state of the rotation angle sensor 25. When the operating state of the rotation angle sensor 25 switches, the activation determination circuit 30 switches the microcomputer 40 from the sleep state to the wake-up state by turning on the normal power supply circuit 21, even if a startup command has not been received. This allows the microcomputer 40 to be properly woken up even when a startup command cannot be obtained from the vehicle communication network 6 due to a communication abnormality, etc.

When communication with the vehicle communication network 6 is not possible, the microcomputer 40 switches from the wake-up state to the sleep state if a non-steering state continues for the non-steering determination time based on a signal from the rotation angle sensor 25. In this embodiment, the non-steering state is considered to be present when in power saving mode. This allows the microcomputer 40 to appropriately transition to the sleep state even when communication with the vehicle communication network 6 is not possible.

Second Embodiment
The second embodiment is shown in Fig. 7. As shown in Fig. 7, in this embodiment, two vehicle communication networks 6 and 7 are connected to the CAN driver 28. Note that the vehicle communication network may have two or more systems. In Fig. 7, the vehicle communication network 6 is indicated as "CAN1" and the vehicle communication network 7 is indicated as "CAN2."

When the CAN signal from either vehicle communication network 6 or 7 is turned on, the trigger output of the CAN driver 28 and the activation determination circuit 30 is turned on, and the normal power supply circuit 21 is turned on, switching the microcomputer 40 from a sleep state to a wake-up state. This allows the microcomputer 40 to be activated by the other vehicle communication network even if an abnormality occurs that prevents signals from being received from one vehicle communication network.

Furthermore, the microcomputer 40 remains in a wake-up state as long as communication from some vehicle communication networks continues, and if communication from all vehicle communication networks stops, it stops assist control and sends a shutdown request to the activation determination circuit 30. When the activation determination circuit 30 shuts off in response to the shutdown request, the normal power supply circuit 21 is turned off and the microcomputer 40 switches to a sleep state. This allows the microcomputer 40 to switch appropriately between a sleep state and a wake-up state. It also achieves the same effects as the above embodiment.

(Third embodiment)
A third embodiment is shown in Figures 8 and 9. In this embodiment, the activation determination circuit 30 is capable of acquiring a vehicle speed signal, a temperature signal, and a switch signal. These signals are acquired via a so-called "direct line" rather than from vehicle communication networks 6 and 7 (not shown in Figure 8). The activation determination circuit 30 is also capable of detecting the power supply voltage, which is the voltage of the battery 5. In this embodiment, the microcomputer 40 can be switched from a sleep state to a wake-up state by turning on the trigger output of the activation determination circuit 30 based on signals related to the vehicle state, such as the vehicle speed signal, the temperature signal, the switch signal, or the power supply voltage.

Specifically, the activation determination circuit 30 is configured to switch the trigger output ON when a vehicle speed signal is acquired. The activation determination circuit 30 is also capable of acquiring engine temperature as a temperature signal, and is configured to switch the trigger output ON when an increase in engine temperature is detected. Note that the temperature signal may be a detection signal from a sensor that directly detects engine temperature, or, since an increase in engine temperature also increases the temperature of the ECU 10, a signal from a temperature sensor such as a thermistor inside the ECU 10 may be used.

The activation determination circuit 30 is configured to use a switch signal related to IG on/off, and to switch the trigger output to on when the IG is turned on. Alternatively, instead of the IG itself, a signal related to the on/off of another switch that is turned on when the IG is turned on may be used as the switch signal.

Furthermore, cranking when the engine is started causes the voltage of the battery 5 to drop. Furthermore, when the alternator starts generating electricity, the voltage of the battery 5 rises. The start-up determination circuit 30 is configured to detect this voltage change and switch the trigger output ON. Note that while the vehicle speed signal, temperature signal, switch signal, and power supply voltage signal are exemplified here as signals related to the switching of the trigger output of the start-up determination circuit 30, some of these may be omitted, or signals from the vehicle communication networks 6 and 7 and the rotation angle sensor 25 in the above embodiment may be used in combination.

The microcomputer sleep process of this embodiment will be explained based on the flowchart in Figure 9. This process is executed at a predetermined interval while the microcomputer 40 is running. The processes of S251 to S255 are the same as the processes of S201 to S205 in Figure 6.

If it is determined that CAN communication is abnormal (S251: NO), the microcomputer 40 proceeds to S256, where it determines whether vehicle operation has stopped. Here, it determines that vehicle operation has stopped because the IG has been turned off, but it may also determine that vehicle operation has stopped by monitoring the power supply voltage to determine whether the alternator has stopped generating electricity, or by the torque sensor signal, engine temperature, etc. If it is determined that vehicle operation has not stopped (S256: NO), the processing of S257 is skipped. If it is determined that vehicle operation has stopped (S256: YES), the processing proceeds to S257. The processing of S257 is the same as the processing of S207 in FIG. 6. Note that the microcomputer startup processing is the same as in the first embodiment, so a description thereof will be omitted.

In this embodiment, a signal indicating the vehicle's operating state is used to switch the microcomputer 40 between a sleep state and a wake-up state. This allows the microcomputer 40 to switch appropriately between a sleep state and a wake-up state. Furthermore, by using multiple signals, the microcomputer 40 can be switched appropriately between a sleep state and a wake-up state even if an abnormality occurs in one of the signals. This also provides the same effects as the above embodiment.

In this embodiment, signals from the vehicle communication networks 6 and 7, signals from the rotation angle sensor 25, vehicle speed signals, temperature signals, switch signals, and signals related to the power supply voltage correspond to "start-up signals according to the operating state of the vehicle." Furthermore, the start of acquisition of CAN signals from the vehicle communication networks 6 and 7, the switching of the rotation angle sensor 25 from power saving mode to normal mode, the start of acquisition of vehicle speed signals, detection of an increase in engine temperature, and detection of a fluctuation in power supply voltage correspond to "trigger states related to the startup of the microcomputer." Note that signals and states other than those exemplified here may also be used as startup signals and trigger states related to the startup of the microcomputer.

(Other embodiments)
In the above embodiment, the steering device is an electric power steering device. In other embodiments, the steering device may be a steer-by-wire device. In this embodiment, the control device is applied to the steering device. In other embodiments, the control device may be applied to an in-vehicle device other than the steering device.

The control unit and method described in the present disclosure may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and method described in the present disclosure may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method described in the present disclosure may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored on a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer. As described above, the present invention is in no way limited to the above embodiments, and various forms may be implemented within the scope of the invention.

5: Battery 6, 7: Vehicle communication network 10: ECU (control device)
25: Rotation angle sensor 30: Start determination circuit 40: Microcomputer 80: Motor

Claims (2)

a microcomputer (40) for performing calculations related to drive control of a motor (80);
an activation determination circuit (30) capable of switching the microcomputer from a sleep state to a wake-up state by a plurality of activation signals corresponding to the operating state of the vehicle;
Equipped with
the activation determination circuit switches the microcomputer from a sleep state to a wake-up state when at least one of the plurality of activation signals becomes a trigger state related to activation of the microcomputer;
The activation signal includes a signal from a vehicle communication network (6, 7) and a signal from a rotation angle sensor (25) that detects the rotation state of the motor and is constantly powered by a battery (5) so that at least a part of the detection operation can continue even while the vehicle switch is turned off.
The motor outputs a torque required for steering,
When a signal from the vehicle communication network can be acquired, the microcomputer is switched from a sleep state to a wake-up state based on the signal from the vehicle communication network, thereby enabling the microcomputer to perform calculations related to drive control of the motor, and determines whether an assist permission signal related to steering assist transmitted from the vehicle communication network is turned on, and starts steering assist control when the assist permission signal is turned on;
When it is detected that the operating state of the rotation angle sensor has changed while no signal is being received from the vehicle communication network, the control device switches the microcomputer from a sleep state to a wake-up state, allowing the microcomputer to perform calculations related to the drive control of the motor, and starts steering assist control without waiting for the assist permission signal . 2. The control device according to claim 1, wherein the microcomputer switches from a wake-up state to a sleep state when communication with the vehicle communication network is not possible and a non-steering state continues for a non-steering determination time based on a signal from the rotation angle sensor.