JP2004291850A - Steering device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device for a vehicle having a sufficient back-up function even if an abnormal state such as a voltage drop occurs at a power supply for the steering device, enabling an electrical power for use in controlling a motor to be always supplied and improving a stability in controlling of the steering operation. <P>SOLUTION: A vehicle (a steering device 1 for a vehicle) is provided with a power supply unit 40 having a plurality of power supplies. The unit 40 has a power supply 41 for a steering device for always supplying an electrical power for driving a motor to motors 6A, 6B, and a power supply 42 for the vehicle for always supplying the electrical power to some electrical parts for the vehicle except the motors 6A, 6B (for example, lamps and meters and the like). Each steering control unit 20A, 20B has the supply 41 selectively supplying a motor drive power to a motor drive circuit for driving the motors 6A, 6B. A power supply 41 for the steering device capable of selectively supplying an electrical power for driving the motor and the supply 42 for the vehicle as a back-up power supply, both arranged parallelly. In turn, the supply 41 for the steering device and the supply 42 for the vehicle are arranged parallelly to constantly supply control power to a motor control circuit C (control units 200A, 200B) for controlling rotation of the motors 6A, 6B. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering device for a vehicle such as an automobile.
[0002]
[Prior art]
2. Description of the Related Art Power steering devices are widely and widely used in vehicle steering devices, particularly in automobile steering devices (see Patent Documents 1 and 2). As another example of a vehicle steering system, a steer-by-wire system in which a handle shaft and a wheel turning shaft are not mechanically connected but are electrically connected via a steering control unit is known. (See Patent Document 3). The steering control unit of these vehicle steering devices determines a steering output such as an assist torque or a steering angle to be applied to a wheel steering shaft in accordance with a steering input such as a steering torque or a steering angle applied to a steering handle shaft. Then, a method of controlling the rotation of the turning shaft drive motor so that the turning output is given to the wheel turning shaft is adopted.
[0003]
By the way, in the vehicle steering apparatus as described above, conventionally, the supply of the motor drive power to the steered shaft drive motor and the supply of the electric power to the vehicle electrical components except the steered shaft drive motor are common. And a common standby power supply (backup power supply) is provided in preparation for a voltage drop of the common power supply.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-168597 [Patent Document 2]
JP 2001-341656 A [Patent Document 3]
JP 2001-88727 A
[Problems to be solved by the invention]
However, when the voltage of the main power supply drops and the power supply is switched from the main power supply to the backup power supply (backup power supply), even if the power supply to the control unit that controls the rotation of the steering shaft drive motor is temporarily interrupted. The steering control may be unstable.
[0006]
An object of the present invention is to improve the stability of steering control by having a sufficient backup function and constantly supplying motor control power even when an abnormality such as a voltage drop occurs in a power supply for a steering device. An object of the present invention is to provide a vehicle steering system.
[0007]
Means for Solving the Problems and Effects of the Invention
In order to solve the above problems, a vehicle steering device according to the present invention includes:
A turning output to be given to the wheel turning shaft is determined in accordance with a steering input given to a steering handle shaft, and the rotation of the turning shaft drive motor is controlled so as to obtain the turning output by the wheel turning. In a vehicle steering device having a steering control unit that moves a rudder axis,
The vehicle is equipped with a plurality of power supplies,
The plurality of power sources include at least a steering device power source that supplies motor driving power to the steering shaft drive motor, and a backup power source,
The steering device power supply and the backup power supply are arranged in parallel so as to be able to selectively supply motor driving power to a motor drive circuit that rotationally drives the steering shaft drive motor. It is characterized by being connected in parallel so that motor control power can be constantly supplied to a control unit that controls the rotation of the rudder shaft drive motor.
[0008]
According to the vehicle steering system, the steering shaft drive motor is supplied with the motor drive power by using the power supply for the steering system as a dedicated power supply at normal times. Therefore, the capacity of the power supply for the steering device can be selected according to the steering shaft drive motor, and the motor drive power can be supplied stably. In addition, since the control unit (motor control circuit) is always supplied with motor control power from the steering device power supply and the backup power supply, even when an abnormality such as a voltage drop occurs in the steering device power supply, the motor is controlled. Stable steering control is ensured without causing troubles such as stoppage of supply of control power. The motor control power is related to signal processing for the steering control unit, and may generally be lower power (lower voltage) than the motor drive power (for example, the motor control power may be reduced to 12 V DC for the motor control power). Although the power is 5 V DC, the steering control may become unstable if the power supply is interrupted even temporarily. Such a situation can be prevented by constantly supplying the motor control power from the steering device power supply and the backup power supply.
[0009]
Further, in order to solve the above-described problems, a vehicle steering device according to the present invention includes:
A turning output to be given to the wheel turning shaft is determined in accordance with a steering input given to a steering handle shaft, and the rotation of the turning shaft drive motor is controlled so as to obtain the turning output by the wheel turning. In a vehicle steering device having a plurality of steering control units that move a rudder axis,
The vehicle is equipped with a plurality of power supplies,
The plurality of power sources include at least a steering device power source that supplies motor driving power to the steering shaft drive motor, and a backup power source,
In each of the steering control units, the power supply for the steering device and the power supply for the backup are arranged in parallel so that electric power for motor driving can be selectively supplied to a motor driving circuit that rotationally drives the steering shaft driving motor. While
In each of the steering control units, the power supply for the steering device and the power supply for the backup are connected in parallel so that power for motor control can always be supplied to a control unit that controls rotation of the steering shaft drive motor. It is characterized by.
[0010]
As described above, even in the vehicle steering system having a plurality of steering control units, when the motor drive power is supplied by the steering system power supply and the backup power supply, the voltage of the steering system power supply may be reduced. Even when an abnormality occurs, power supply to the turning shaft drive motor is not interrupted. Therefore, even in the steer-by-wire type vehicle steering system, it is possible to avoid a state in which steering cannot be performed. In addition, since power for motor control is constantly supplied to the control unit (motor control circuit) of each steering control unit from the power source for the steering device and the power source for backup, an abnormality such as a voltage drop occurs in the power source for the steering device. Even in this case, stable steering control can be ensured in any of the steering control units without causing a trouble such as a stoppage of supply of electric power for motor control.
[0011]
In addition, when there are two steering control units, for example, the following steering control system can be constructed.
{Circle around (1)} A case in which one steering shaft drive motor is rotationally controlled by two steering control units: one of the two steering control units is used as a main steering control unit, and the other is used as a backup steering control unit. .
(2) A case in which each of the two steering control units is provided with a steering shaft drive motor, and controls the rotation of each of the steering shaft drive motors to simultaneously control the left and right wheels with one wheel steering shaft. : Each steering control unit is used as a shared steering control unit that controls the left and right wheels simultaneously in the same direction at the same turning angle.
(3) Each of the two steering control units is provided with a steering shaft drive motor, and controls the rotation of each steering shaft drive motor to move the left and right wheel steering shafts independently (the rotation of the left and right wheels). Case in which the steering angle is independently changed): Each steering control unit is used as a dedicated steering control unit that controls the left and right wheels individually.
[0012]
In these steering control systems, each of the plurality of steering control units is provided with a steering shaft drive motor for moving a wheel steering shaft (in the case of (2) and (3) above), each steering control is performed. It is desirable that the power supply for the steering device and the backup power supply be connected in parallel to the unit so that the control unit that controls the rotation of each of the turning shaft drive motors can always supply the power for motor control. Since the motor control power can be constantly supplied to the control unit of each motor, stable steering control is ensured for any motor.
[0013]
In these vehicle steering devices, a power source for the steering device and a power source for the backup are connected in parallel so that power for motor drive can be selectively supplied to a motor drive circuit that rotationally drives the steering shaft drive motor. The power supply for the motor drive circuit may be switched from the power supply for the steering device to the backup power supply when an abnormality occurs in the power supply for the steering device connected to the motor drive circuit. As a result, a backup function for the motor drive circuit can be provided relatively simply by setting a predetermined threshold value. In addition, contact switching of an electromagnetic relay or the like can be used as the power supply switching means.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Example 1)
FIG. 1 schematically shows an entire configuration of a steer-by-wire type steering device as an example of a vehicle steering device to which the present invention is applied (in the present embodiment, “vehicle” is an automobile. However, the application object of the present invention is not limited to this. This vehicle steering system 1 is configured in a steer-by-wire system in which a handle shaft 3 directly connected to a steering handle 2 and a wheel steering shaft 11 are mechanically separated. On the wheel steering shaft 11, steering shaft drive motors (hereinafter, also simply referred to as motors) 6A, 6B and reduction mechanisms 12A, 12B are coaxially assembled. As a result, the rotation of the motors 6A, 6B is transmitted to the wheel steering shaft 11 via the speed reduction mechanisms 12A, 12B, the wheel steering shaft 11 reciprocates in the axial direction, and the steering angles of the wheels 13, 13 change. I do.
[0015]
The angle position φ of the handle shaft 3 is detected as a steering angle (steering input) by a handle shaft angle detector 14 including a known angle detector such as a rotary encoder. On the other hand, the rotation angle positions θA and θB of the motors 6A and 6B are detected as the turning angles (turning outputs) by the motor angle position detection units 15A and 15B, which also include rotary encoders and the like. Then, the steering control unit 20 determines the target rotation angle positions θA ′, θB ′ of the motors 6A, 6B based on the detected angle position φ of the handle shaft 3, and determines the rotation angle positions θA, The operation of the motors 6A and 6B is controlled so that θB approaches the target rotation angle positions θA ′ and θB ′.
[0016]
FIG. 2 is a block diagram of the vehicle steering system 1. The vehicle (vehicle steering device 1) includes a power supply unit 40 having a plurality of power supplies. In this embodiment, the power supply unit 40 supplies power to the steering device 41 that constantly supplies electric power for driving the motors to the motors 6A and 6B, and electric power for vehicles (such as lamps and meters) other than the motors 6A and 6B. And a vehicle power supply 42 that constantly supplies the power. The steering control unit of the vehicle steering system 1 includes a plurality of (two in the figure) steering control units 20A and 20B each equipped with CPUs 23A and 23B, and a motor for each of the steering control units 20A and 20B. 6A and 6B are provided. Each of the steering control units 20A and 20B is provided with a steering device power supply 41 and a backup power supply so that motor driving power can be selectively supplied to a motor driving circuit P that rotationally drives the respective motors 6A and 6B. And a vehicle power supply 42 are arranged in parallel.
[0017]
Specifically, the power supply 41 for the steering device and the power supply 42 for the vehicle are alternatively connected to the motor drive circuit P via the switching means 5 (switching circuit) of the steering control units 20A and 20B, and the motor drive The circuit P is connected to drivers 18A and 18B of the motors 6A and 6B via power filters 22A and 22B. The switching means 5 disconnects the power supply 41 for the steering system from the motor drive circuit P when the power supply 41 for the steering system constantly connected to the motor drive circuit P drops below a predetermined value (threshold). After confirming that there is no ground fault, the power supply of the motor drive circuit P is switched from the power supply 41 for the steering device to the power supply 42 for the vehicle.
[0018]
Similarly, the power supply 41 for the steering device and the power supply 42 for the vehicle are alternatively connected to the vehicle drive circuit P ′ via the switching means 5 ′ of the vehicle supply unit 30, and the vehicle drive circuit P ′ is connected to the power supply Via a filter 32, it is connected to vehicle electrical components (not shown) such as lamps and meters. The switching means 5 'disconnects the vehicle power supply 42 from the vehicle drive circuit P' when the vehicle power supply 42 which is always connected to the vehicle drive circuit P 'drops below a predetermined value (threshold). After confirming that the power supply 41 for the vehicle is not grounded, the power supply of the vehicle drive circuit P 'is switched from the power supply 42 for the vehicle to the power supply 41 for the steering device.
[0019]
The first steering control unit 20A and the second steering control unit 20B have the same structure. Therefore, the first steering control unit 20A will be described as a representative of both, and the description of the second steering control unit 20B will be omitted. The first steering control unit 20A has a CPU 23A, a RAM 24A, a ROM 25A, an input / output interface 26A, and the like, and includes a control unit 200A that is connected to these via a bus 27A so as to be able to transmit and receive. The power supply 41 for the steering device and the power supply 42 for the vehicle are connected at the point A via normally closed switches 29A, 29A and backflow prevention diodes 21A, 21A, respectively, and are inputted to the voltage adjusting means 28. After that, the voltage controlled by the voltage adjusting means 28 (for example, converted from DC + 12V to DC + 5V) passes through the motor control circuit C and is input to the control unit 200A. The power supply 41 for the steering device and the power supply 42 for the vehicle are connected in parallel so that the control unit 200A (motor control circuit C) that controls the rotation of the motor 6A can always supply motor control power.
[0020]
The input / output interface 26A includes an angle position φ of the handle shaft angle detection unit 14, a rotation angle position θA of the motor angle position detection unit 15A, a voltage value V (described later) of the switching unit 5 (motor drive circuit P), and the like. Is entered. On the other hand, from the input / output interface 26A, a rotation control command for the motor 6A to the driver 18A, a switching control command (described later) to the switching means 5, and the like are output.
[0021]
The method of switching the power supply circuit connected to the motor drive circuit P by the switching means 5 will be described in detail with reference to FIG. When the voltage of the steering device power supply 41 connected to the motor drive circuit P drops below a predetermined value (threshold; see FIG. 3C), the switching means 5 disconnects the steering device power supply 41 from the motor drive circuit P. After a lapse of a predetermined time (delay time; see FIG. 3C), the power supply of the motor drive circuit P is switched from the power supply 41 for the steering device to the power supply 42 for the vehicle.
[0022]
Specifically, the switching means 5 (switching circuit) includes a voltage monitor 5a for monitoring the voltage of the motor drive circuit P, a series circuit of an electromagnetic relay 5b (R; relay) and a relay driver 5x, and a timer relay 5c (TLR). A time-relay; an on-delay timer) and a series circuit of a timer relay driver 5y. The electromagnetic relay 5b (R) and the timer relay 5c (TLR) are supplied with a potential (for example, DC + 12V) of the motor control circuit C before voltage adjustment from the above-described connection point A (see FIG. 2). A normally closed contact 5d (R-b) interlocked with the electromagnetic relay 5b (R) is provided in a circuit connected to the power supply 41 for the steering device. On the other hand, a normally open contact 5e (TLR-a) interlocked with the timer relay 5c (TLR) is provided in a circuit connected to the vehicle power supply 42. Thereby, when the power supply 41 for the steering device connected to the motor drive circuit P drops below a predetermined value, the normally closed contact 5d (R-b) of the electromagnetic relay 5b (R) is switched to the open state, The power supply 41 for the steering device is disconnected from the motor drive circuit P. After the elapse of the predetermined time (the delay time set by the timer relay 5c), the normally open contact 5e (TLR-a) of the timer relay 5c (TLR) is switched to the closed state, and the power supply of the motor drive circuit P is switched to the steering device. The power source 41 is switched to the vehicle power source 42.
[0023]
In the switching means 5 'of the vehicle supply unit 30 shown in FIG. 2, the connection position between the normally closed contact 5d (Rb) and the normally open contact 5e (TLR-a) in FIG. used.
[0024]
Next, the contents of the power supply switching program executed mainly by the CPU 23A will be described with reference to the flowchart of FIG. The voltage value of the motor drive circuit P (the power supply 41 for the steering device) is monitored by the voltage monitor 5a (see FIG. 3A) (S1), and it is checked whether the voltage has fallen below the set threshold value. (S2). If the voltage has fallen below the threshold (YES in S2), the electromagnetic relay 5b (R) and the timer relay 5c (TLR) are activated via the relay driver 5x and the timer relay driver 5y (S3). ). When the electromagnetic relay 5b (R) is excited, the normally closed contact 5d (Rb) is opened, and the power supply 41 for the steering device is disconnected from the motor drive circuit P (S4; see FIGS. 3 (b) and 3 (c)). After the elapse of the delay time, the normally open contact 5e (TLR-a) is closed by excitation of the timer relay 5c (TLR), and the vehicle power supply 42 is connected to the motor drive circuit P (S5; FIG. 3B). c)).
[0025]
Again, the voltage value of the motor drive circuit P (vehicle power supply 42) is monitored by the voltage monitor 5a (see FIG. 3A) (S6), and it is checked whether the voltage has dropped below the set threshold value. (S7). If the voltage has dropped below the threshold value (YES in S7), it is determined that both the power supply 41 for the steering system and the power supply 42 for the vehicle cannot supply sufficient drive power to rotate the motor 6 to the motor drive circuit P. An alarm is output, and the electromagnetic relay 5b (R) and the timer relay 5c (TLR) are deactivated via the relay driver 5x and the timer relay driver 5y (S8). As a result, the normally closed contact 5d (Rb) is instantaneously closed and the normally open contact 5e (TLR-a) is opened, so that the power supply 41 for the steering device is again connected to the motor drive circuit P (FIG. 3A )reference). Although the voltage of the power supply 41 for the steering device is detected by the voltage monitor 5a to be lowered, the steering is performed with the surplus of the voltage to prevent the steering from being disabled.
[0026]
As described above, the vehicle power supply 42 functions as a backup power supply when the voltage of the steering device power supply 41 drops, so that even in the steer-by-wire type vehicle steering device 1 as in the present embodiment, the steering impossible state is avoided. be able to. Further, in the present embodiment, when the power supply 41 for the steering device connected to the motor drive circuit P drops in voltage below a predetermined value (threshold), the power supply 41 is disconnected from the motor drive circuit P, and after a lapse of a predetermined time (delay time), The power supply of the motor drive circuit P is switched from the power supply 41 for the steering device to the power supply 42 for the vehicle. As a result, even when the vehicle power supply 42 as a backup power supply is grounded at the time of a voltage drop of the steering device power supply 41, a time lag is provided before switching, so that both power supplies 41, It is possible to avoid a voltage drop from occurring in both cases. In the switching circuit 5, two electromagnetic relays are used instead of using the electromagnetic relay 5b and the timer relay 5c, and a predetermined time after the switching of the first electromagnetic relay (a delay time set in advance and based on a clock signal from the CPU 23). After the passage, the second electromagnetic relay may be switched.
[0027]
Further, since the power supply 41 for the steering device and the power supply 42 for the vehicle are connected in parallel so as to always supply power for motor control to the control units 200A and 200B for controlling the rotation of the motors 6A and 6B, The control power can always be supplied, and it is possible to prevent a situation in which the steering control becomes unstable or a ground fault cannot be confirmed.
[0028]
(Example 2)
FIG. 5A shows another embodiment of the circuit configuration of the switching means, which can be used in place of FIG. 3A (first embodiment). FIGS. 5B and 5C show a timing chart and a graph showing a voltage change of the motor drive circuit when the switching means of FIG. 5A is used, respectively.
[0029]
A method of switching the power supply circuit connected to the motor drive circuit P by the switching means 50 of FIG. 5A will be described. When the voltage of the steering device power supply 41 connected to the motor drive circuit P drops below a predetermined value (threshold; see FIG. 5C), the switching means 50 disconnects the steering device power supply 41 from the motor drive circuit P. Then, immediately (no delay time; see FIG. 5C), the power supply of the motor drive circuit P is switched from the power supply 41 for the steering device to the power supply 42 for the vehicle.
[0030]
Specifically, the switching means 50 (switching circuit) has a voltage monitor 5a for monitoring the voltage of the motor drive circuit P, and a series circuit of an electromagnetic relay 50b (R; relay) and a relay driver 50x. . As in the first embodiment (FIG. 3A), the potential (for example, DC + 12 V) of the motor control circuit C before voltage adjustment is applied to the electromagnetic relay 50b (R) from the connection point A (see FIG. 2). Has been given. A normally closed contact 50d (R-b) interlocked with the electromagnetic relay 50b (R) is provided in a circuit connected to the power supply 41 for the steering device, and a normally open contact 50e (R-b) also interlocked with the electromagnetic relay 50b (R). a) is provided in a circuit connected to the vehicle power supply 42. Thus, when the power supply 41 for the steering device connected to the motor drive circuit P drops below a predetermined value, the normally closed contact 50d (R-b) of the electromagnetic relay 50b (R) is switched to the open state, The power supply 41 for the steering device is disconnected from the motor drive circuit P. At the same time, the normally open contact 50e (Ra) of the electromagnetic relay 50b (R) is switched to the closed state, and the power supply of the motor drive circuit P is switched from the power supply 41 for the steering device to the power supply 42 for the vehicle.
[0031]
The circuits connected in parallel with the motor drive circuit P and connected to the power supply 41 for the steering device and the power supply 42 for the vehicle are provided with diodes 51b and 51a for backflow prevention, respectively. When the power supply connected to the motor drive circuit P is switched between the power supply 41 for the steering device and the power supply 42 for the vehicle by these diodes 51b and 51a, a current flows backward and a ground fault occurs. The occurrence of a voltage drop in both power supplies is prevented.
[0032]
When the switching means 50 of FIG. 5A is used, the flowchart of FIG. 4 (Embodiment 1) is changed to that of FIG. 6 and executed. That is, in S30 instead of S3 in FIG. 4, the electromagnetic relay 50b is operated, and in S50 instead of S5 in FIG. 4, the switching to the vehicle power supply 42 is performed simultaneously with the disconnection of the steering device power supply 41. Further, in S80 instead of S8 in FIG. 4, the electromagnetic relay 50b (R) is deactivated via the relay driver 50x together with the alarm output. As a result, the normally closed contact 50d (Rb) is instantaneously closed and the normally open contact 50e (Ra) is opened, so that the power supply 41 for the steering device is again connected to the motor drive circuit P (FIG. 5 (a) )reference).
[0033]
The above description has been made only for the steer-by-wire type steering device, but can also be applied to a power steering device. These vehicle steering devices include various types such as an electric type, an electro-hydraulic type, a variable steering output type such as a speed-sensitive type and a rotational speed-sensitive type. The power supply unit 40 may have a plurality of power supplies, and the number of steering control units and motors may be one or more. Further, these numbers can be appropriately combined. For example, a combination of two steering control units, one motor, one steering control unit, two motors, and the like can be selected. Further, (1) a method in which the left and right wheels 13, 13 are simultaneously steered in the same direction at the same steering angle by the two motors shown in FIG. 1, and (2) the left and right wheels 13, 13 are individually steered. A method (a configuration in which the wheel steering shaft 11 is not connected between the motors 6A and 6B) and the like can be selected.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a steer-by-wire type steering device as an example of a vehicle steering device to which the present invention is applied.
FIG. 2 is a block diagram of the vehicle steering system shown in FIG. 1;
FIG. 3 is a circuit configuration diagram of a switching unit, a timing chart thereof, and a graph showing a voltage change of a motor drive circuit.
FIG. 4 is a flowchart showing the contents of a power supply switching program.
FIG. 5 is a circuit configuration diagram of a switching unit showing another embodiment, a timing chart thereof, and a graph showing a voltage change of a motor drive circuit.
FIG. 6 is a flowchart showing the contents of a power supply switching program corresponding to FIG. 5;
[Explanation of symbols]
1 Vehicle steering system (steer-by-wire steering system)
3 Handle shaft 5 Switching means (switching circuit)
6. Motor (steering shaft drive motor)
11 wheel steering shaft 20 steering control unit 20A first steering control unit (steering control unit)
20B Second steering control unit (steering control unit)
200 control unit 200A first control unit (control unit)
200B second control unit (control unit)
40 power supply unit 41 power supply for steering device 42 power supply for vehicle (power supply for backup)
C Motor control circuit P Motor drive circuit

Claims (4)

A turning output to be given to the wheel turning shaft is determined in accordance with a steering input given to a steering handle shaft, and the rotation of the turning shaft drive motor is controlled so as to obtain the turning output by the wheel turning. In a vehicle steering device having a steering control unit that moves a rudder axis,
The vehicle is equipped with a plurality of power supplies,
The plurality of power sources include at least a steering device power source that supplies motor driving power to the steering shaft drive motor, and a backup power source,
The steering device power supply and the backup power supply are arranged in parallel so as to be able to selectively supply motor driving power to a motor drive circuit that rotationally drives the steering shaft drive motor. A vehicle steering device, which is connected in parallel so that a control unit that controls rotation of a rudder shaft drive motor can always supply motor control power. A turning output to be given to the wheel turning shaft is determined in accordance with a steering input given to a steering handle shaft, and the rotation of the turning shaft drive motor is controlled so as to obtain the turning output by the wheel turning. In a vehicle steering device having a plurality of steering control units that move a rudder axis,
The vehicle is equipped with a plurality of power supplies,
The plurality of power sources include at least a steering device power source that supplies motor driving power to the steering shaft drive motor, and a backup power source,
In each of the steering control units, the power supply for the steering device and the power supply for the backup are arranged in parallel so that electric power for motor driving can be selectively supplied to a motor driving circuit that rotationally drives the steering shaft driving motor. While
In each of the steering control units, the power supply for the steering device and the power supply for the backup are connected in parallel so that power for motor control can always be supplied to a control unit that controls rotation of the steering shaft drive motor. A vehicle steering system characterized by the above-mentioned. Each of the plurality of steering control units is equipped with the turning shaft drive motor that moves the wheel turning shaft,
Each of the steering control units is connected in parallel with the power supply for the steering device and the power supply for the backup so that the control unit for controlling the rotation of the respective steering shaft drive motors can always supply the power for motor control. The vehicle steering device according to claim 2, wherein The power supply for the steering device and the power supply for the backup are arranged in parallel so as to be able to selectively supply power for motor drive to a motor drive circuit that rotationally drives the steering shaft drive motor,
The power supply for the motor drive circuit is switched from the power supply for the steering device to the backup power supply when an abnormality occurs in the power supply for the steering device connected to the motor drive circuit. The vehicle steering system according to claim 1.

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