JP7320348B2 - Steering system and vehicle equipped with same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a steering system and a vehicle equipped with the same, and more particularly to technology for improving the redundancy of the steering system.

In a vehicle represented by an automobile, a steering wheel and a steering device are mechanically connected, and the steering device steers the wheels by turning the steering wheel (Patent Documents 1 to 4).
However, in a vehicle in which the steering wheel and the steering device are mechanically connected, there is a problem in that the steering wheel is pulled and the vehicle wobbles due to reverse input from the wheels due to unevenness of the road surface.
Also, during cornering, there is a problem that the running stability and follow-up performance to the steering wheel operation are degraded due to variations in the driver's proficiency level or environmental conditions such as the road surface.

JP 2009-226972 A DE 102012206337 A1 JP 2014-061744 A JP 2016-147513 A

In order to solve the above problem, the first steering device, which controls the steering angle by the steering wheel operation by the driver, corrects the direction of the vehicle by changing the angle of each of the left and right tires, thereby stabilizing the running of the vehicle. Provided is a second steering device capable of improving performance and the like.
However, in the second steering device, if an abnormality occurs in either one or both of the electric power systems from the power source during control of the vehicle while the vehicle is running, the direction of the tires is fixed in the direction at the time of the electric power system abnormality. There is a problem that it becomes difficult to operate the steering wheel.

SUMMARY OF THE INVENTION An object of the present invention is to provide a steering system capable of improving the running stability of a vehicle and capable of maintaining follow-up performance to steering wheel operation, etc., even when an abnormality occurs in the electric power system, and a vehicle equipped with the steering system. to provide.

A steering system 101 of the present invention is a steering system provided in a vehicle 100,
a first steering device 11 that steers the left and right front wheels 9F, 9F of the vehicle 100 according to steering amount commands output from the steering command devices 200, 200A;
a second steering device 150 for individually steering either one or both of the front and rear wheels by driving the steering actuator 5 provided in the vehicle 100;
a main power source Bm and a sub power source Bs that supply power to the second steering device 150;
A vehicle information detection unit 110 that detects vehicle information representing the state of the vehicle,
The second steering device 150 individually controls the steering actuator 5 of the other of the left and right wheels based on the vehicle information including the steering angle of one of the left and right wheels. provided with actuator control devices 31L and 31R of
The left and right wheel actuator control devices 31L, 31R respectively detect whether or not there is an abnormality in the power systems 223R, 223L supplied from the main power source Bm to the actuator control devices 31R, 31L. Detection units 221 and 222 are provided, and when one of the abnormality detection units 221 and 222 for the left and right wheels detects an abnormality in the corresponding electric power system, the abnormality detection information is sent to the abnormality detection unit 221 for the left and right wheels. , 222 has a mutual monitoring function to provide each other to the other abnormality detection unit,
power is supplied from the main power supply Bm to the left and right wheel actuator control devices 31L and 31R, respectively, when there is no abnormality in either power system by the left and right wheel abnormality detection units 221 and 222;
When abnormality detection information is provided from one of the abnormality detection sections 221 and 222 for the left and right wheels to the other abnormality detection section of the abnormality detection sections for the left and right wheels, the secondary power system is replaced with the abnormality detection section. Power is supplied from the power source Bs to the actuator control device including the one abnormality detection section.

According to this configuration, since the second steering device 150 is provided, even if the vehicle 100 slightly wobbles, the wobble of the vehicle 100 can be corrected without the driver operating the steering wheel. Therefore, the straight running stability of the vehicle 100 is improved.
When cornering, the driver's steering operation is corrected according to the vehicle information so that the steering amount of each of the left and right wheels is corrected so that the vehicle can turn more efficiently. Since the operation load can be reduced, the steering stability of the vehicle 100 can be improved.

When there is no abnormality in either power system 223R, 223L, power is supplied from the main power supply Bm to the left and right wheel actuator control devices 31L, 31R, respectively.
Since the left and right wheel actuator control devices 31L and 31R are provided with left and right wheel abnormality detection units 221 and 222 having a mutual monitoring function, when an abnormality occurs in the power system supplied from the main power source Bm to one of the actuator control devices , one abnormality detection section in one actuator control device provides abnormality occurrence information to the other abnormality detection section. The other actuator control device provided with the other abnormality detection unit to which the abnormality occurrence information is supplied supplies power from the auxiliary power source Bs to the one actuator control device instead of the power system with the abnormality.

By supplying power from the auxiliary power supply Bs when the power systems 223R and 223L are abnormal in this way, the toe angles of the left and right wheels are adjusted to, for example, predetermined reference values, and then the steering actuators 5 are operated. It becomes possible to stop the control. By fixing the toe angles of the left and right wheels, which is the initial state of the vehicle, to predetermined reference values, the vehicle is in the initial state without the second steering device 150, so that the driver can safely steer the steering wheel. The command device 200 can be used to move the vehicle to a safe location such as the shoulder of the road. In this way, even when an abnormality occurs in the electric power system, it is possible to maintain followability to the steering wheel operation or the like.

The first steering device 11 may steer the left and right front wheels 9F, 9F in conjunction with each other, and the second steering device 150 may steer the left and right wheels independently. When the second steering device 150 can independently steer the left and right rear wheels 9R, 9R, the behavior of the vehicle is corrected not only by the left and right front wheels 9F, 9F but also by the left and right rear wheels 9R, 9R. Since it can be compensated for, the vehicle can be appropriately controlled.

The first and second steering devices 11 and 150 may steer the same front wheel 9F. In this case, for example, in a high speed range, by changing the angles of the left and right front wheels 9F, 9F and setting parallel geometry, it is possible to smoothly turn without increasing running resistance.

The vehicle information may include vehicle speed, steering angle, vehicle height, actual yaw rate, actual lateral acceleration, accelerator command value, and brake command value. In this case, the second steering device 150 detects the state of the contact surface between the left and right tires and the ground based on the detected vehicle speed, steering angle, vehicle height, actual yaw rate, actual lateral acceleration, accelerator command value, and brake command value. It is possible to calculate the right and left tire angles for cornering the vehicle on an ideal line, and drive the left and right steering actuators 5 individually.

The first steering device 11 and the second steering device 150 may steer different wheels. In this case, in the low speed region, the left and right wheel actuator control devices 31L and 31R steer the left and right rear wheels 9R and 9R in opposite phases to the steering angle of the front wheels 9F and 9F, thereby steering only the front wheels. It is possible to make the minimum turning radius smaller. As a result, it is possible to improve the maneuverability of the vehicle.
At high speeds, the left and right wheel actuator control devices 31L and 31R steer the left and right rear wheels 9R and 9R in the same phase with respect to the steering angle of the front wheels 9F and 9F, thereby suppressing skidding and making it easier to change lanes. It becomes possible to improve the stability of the vehicle.

The vehicle information may include vehicle speed, steering angle, actual yaw rate, actual lateral acceleration, accelerator command value, and brake command value. In this case, the second steering device 150 calculates the state of the contact surface between the left and right tires and the ground based on the detected vehicle speed, steering angle, actual yaw rate, actual lateral acceleration, accelerator command value, and brake command value. , the left and right tire angles for cornering the vehicle on an ideal line can be calculated, and the left and right steering actuators 5 can be individually driven.

Two second steering devices 150 are provided,
The second steering device 150 ₁ on one side and the first steering device 11 steer the same wheels,
On the other hand, the second steering device ₁₅₀₂ and the first steering device 11 may steer different wheels.
In this case, it is possible to adjust the angles of all the wheels independently according to the vehicle information, and the steering geometry can be freely changed, so that the motion performance of the vehicle can be improved.

When the abnormality detection information is supplied from one abnormality detection section to the other abnormality detection section, the actuator control devices 31L and 31R for the left and right wheels transmit the auxiliary power supply Bs to the actuator control device having the one abnormality detection section. Electric power may be supplied to continue control of the steering actuator 5 . In this case, even if an abnormality occurs in one of the electric power systems, the second steering device 150 can steer the left and right wheels individually and adjust the toe angles of the left and right wheels individually and continuously. It is possible.

The actuator control devices 31L and 31R for the left and right wheels return the toe angles of the left and right wheels to predetermined reference values when the abnormality detection information is supplied from one of the abnormality detection units to the other abnormality detection unit. It may be one that controls the actuator 5 for the device.
The predetermined reference value is a reference value that is arbitrarily determined by design or the like, and is determined, for example, by obtaining an appropriate reference value through either one or both of tests and simulations.
In this case, since the steering actuators 5 are controlled so as to return the toe angles of the left and right wheels to a predetermined reference value, a secondary power source Bs with a small capacity is sufficient, and the steering system 101 can be downsized. Become.

A secondary battery, a capacitor, or a condenser may be used as the secondary power supply Bs.

As the second steering device 150,
a hub unit body 2 having a hub bearing 15 that supports the wheel 9F (9R);
A unit support member 3 which is provided in a suspension frame part 6 of a suspension system 12 and supports the hub unit body 2 so as to be rotatable around a steering axis A extending in the vertical direction; A steering hub unit 1 having a steering actuator 5 that rotates around the center A may be used.

According to this configuration, the hub unit main body 2 including the hub bearings 15 that support the wheels 9F (9R) can be freely rotated around the turning axis A by driving the steering actuator 5 . As a result, in addition to the normal steering of the steered wheels, steering of the steered wheels or the non-steered wheels can be performed at a very small angle. Therefore, it is possible to change the steering geometry during turning, thereby improving the running stability of the vehicle. Even when driving in a straight line, by adjusting the amount of toe angle according to each situation, it is possible to reduce running resistance at low speeds without deteriorating fuel efficiency, while ensuring running stability at high speeds.

A vehicle according to the present invention includes a steering system 101 having any one of the above configurations according to the present invention. Therefore, the steering system of the present invention has the advantages described above.

A steering system of the present invention is a steering system provided in a vehicle, comprising: a first steering device for steering left and right front wheels of the vehicle according to a steering amount command output by a steering command device; a second steering device for individually steering either one or both of the front and rear wheels by driving an actuator for the vehicle; a main power source and a secondary power source for supplying electric power to the second steering device; and a vehicle information detection unit that detects vehicle information representing a state of the vehicle, and the second steering device detects the vehicle state of the left and right wheels based on the vehicle information including the steering angle of one of the left and right wheels. Left and right wheel actuator control devices are provided for individually controlling the steering actuators of the other wheels, and the left and right wheel actuator control devices are configured to operate when there is an abnormality in each electric power system supplied from the main power supply to each of the actuator control devices. When one of the left and right wheel abnormality detection units detects an abnormality in the corresponding electric power system, the abnormality detection information is sent to the left and right wheels. An actuator control device for the left and right wheels from the main power supply when there is no abnormality in either of the power systems by the abnormality detection unit for the left and right wheels, and has a mutual monitoring function to provide mutual monitoring to the other abnormality detection unit in the abnormality detection unit for the wheels. respectively, and when the abnormality detection information is given from one abnormality detection section of the left and right wheel abnormality detection sections to the other abnormality detection section of the left and right wheel abnormality detection sections, the power system with the abnormality is replaced with Then, power is supplied from the auxiliary power supply to the actuator control device having the one abnormality detection section. Therefore, the running stability of the vehicle can be improved, and even when an abnormality occurs in the electric power system, it is possible to maintain followability to the steering wheel operation or the like.

Since the vehicle of the present invention is equipped with the steering system of the above-described configuration of the present invention, it is possible to improve the running stability of the vehicle, and even when an abnormality occurs in the electric power system, it is possible to follow the steering wheel operation and the like. can be maintained.

1 is a diagram schematically showing a conceptual configuration of a steering system according to a first embodiment of the invention; FIG. FIG. 4 is a vertical cross-sectional view showing the configuration of a mechanical portion of a second steering device and its surroundings in the same steering system; It is a horizontal sectional view which shows the structures, such as a mechanism part of the said 2nd steering apparatus. It is a perspective view which shows the external appearance of the mechanism part of the said 2nd steering apparatus. It is an exploded front view of a mechanical portion of the second steering device. It is a front view of the mechanism part of the same 2nd steering device. It is a top view of the mechanism part of the same 2nd steering device. FIG. 7 is a cross-sectional view taken along line VIII-VIII of FIG. 6; It is a block diagram showing a conceptual configuration of the same steering system. It is a block diagram showing a conceptual configuration of the second steering device. 4 is a flowchart showing step by step the process when an abnormality occurs in the electric power system. It is a block diagram which shows the structure of the steering control part of the said 2nd steering device. 5 is a graph showing an example of the relationship between actual lateral acceleration/standard lateral acceleration, tire angle, and friction coefficient; FIG. 2 is a diagram schematically showing the conceptual configuration of a steering system according to a second embodiment of the invention; FIG. It is a block diagram showing a conceptual configuration of the same steering system. It is a block diagram which shows the structure of the steering control part of the 2nd steering device of the steering system. FIG. 3 is a diagram schematically showing the conceptual configuration of a steering system according to a third embodiment of the invention; FIG. It is a block diagram showing a conceptual configuration of the same steering system.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIGS. 1 to 13. FIG.
FIG. 1 is a diagram schematically showing the conceptual configuration of a vehicle 100 such as an automobile equipped with a steering system 101 according to this embodiment. The vehicle 100 is a four-wheeled vehicle having left and right front wheels (left and right wheels) 9F, 9F and left and right rear wheels 9R, 9R. may

The steering system 101 is a system for steering a vehicle 100, and includes a first steering device 11, a second steering device 150, a vehicle information detection section 110, a main power source Bm and a secondary power source Bs. Prepare.
The first steering device 11 is a device that steers the left and right front wheels 9F, 9F that serve as steered wheels of the vehicle 100 by a driver's operation of a steering command device 200 such as a steering wheel. ing.

The second steering device 150 is a device that performs auxiliary steering by control according to the state of the vehicle 100, and has a mechanism section 150a and a control section 150b. The mechanism portion 150a is a mechanism provided for each of the front wheels 9F, 9F that are the targets of the assist steering. The mechanism portion 150a is provided in the tire housing 105 of the vehicle 100 and steers the front wheels 9F individually by driving the steering actuator 5 (FIG. 2). Control unit 150b performs control based on vehicle information representing the state of vehicle 100 detected by vehicle information detection unit 110 .

In other words, the steering system 101
The left and right front wheels 9F, 9F of the vehicle 100 are mechanically interlocked, and the left and right front wheels 9F, 9F of the vehicle 100 are installed in accordance with the steering amount command output by the steering command device 200. a first steering device 11 that steers by changing the angles of the knuckles 6, 6 that are the left and right underbody frame parts of the suspension device 12;
By driving the steering actuators 5 (Fig. 2) provided for the left and right front wheels 9F, 9F respectively, the angles of the front wheels 9F, 9F with respect to the knuckles 6, 6, which are the suspension frame parts, are changed to change the angle of the front wheels 9F, 9F. a second steering device 150 for individually steering 9F, 9F;
a vehicle information detection unit 110, which will be described later;
A main power source Bm and a secondary power source Bs for supplying power to the second steering device 150 are provided.

The vehicle information detection unit 110 is means for detecting the state of the vehicle 100, and refers to a group of various sensors. Vehicle information detected by the vehicle information detection unit 110 is transferred to the control unit 150 b of the second steering device 150 via the main ECU 130 .
ECU 130 is a control device that performs coordinated control or integrated control of the entire vehicle 100, and is also referred to as a VCU.

<Configuration of first steering device 11>
The first steering device 11 is a system that interlocks and steers the left and right front wheels 9F, 9F in response to an input to the steering command device 200 such as a steering wheel by the driver. ), and has a well-known mechanical configuration such as the tie rod 14 . When the driver gives a rotation input to the steering command device 200, the steering shaft 32 is also rotated accordingly. When the steering shaft 32 rotates, the tie rod 14 connected to the steering shaft 32 by the rack and pinion moves in the vehicle width direction, thereby changing the direction of the front wheel 9F and steering the left and right front wheels 9F, 9F in conjunction. Is possible.

<Schematic Configuration of Second Steering Device 150>
As shown in FIGS. 1 and 9, the second steering device 150 can independently steer the left and right front wheels 9F, 9F. As a mechanical portion 150a of the second steering device 150, a right wheel hub unit 1R and a left wheel hub unit 1L are provided. The right wheel hub unit 1R and the left wheel hub unit 1L steer the front wheels 9F, 9F by a steering actuator 5 (FIG. 2) provided in the tire housing 105. As shown in FIG.

<Specific Configuration Example of Mechanism Section 150a of Second Steering Device 150>
The mechanism portion 150a of the second steering device 150 includes the right wheel hub unit 1R and the left wheel hub unit 1L as described above. It is configured as a hub unit 1 with functions.
As shown in FIG. 2, the hub unit 1 includes a hub unit body 2, a unit support member 3, a rotation-permitting support member 4, and a steering actuator 5. As shown in FIG. A unit support member 3 is provided integrally with a knuckle 6, which is an underbody frame component.

As shown in FIG. 5 , the actuator body 7 of the steering actuator 5 is provided on the inboard side of the unit support member 3 , and the hub unit body 2 is provided on the outboard side of the unit support member 3 . When the hub unit 1 (FIG. 2) is mounted on the vehicle, the outer side in the vehicle width direction of the vehicle is called the outboard side, and the center side in the vehicle width direction is called the inboard side.
As shown in FIGS. 3 and 4 , the hub unit main body 2 and the actuator main body 7 are connected by a joint portion 8 . Normally, this joint portion 8 is attached with a boot (not shown) for waterproofing and dustproofing.

As shown in FIG. 2, the hub unit main body 2 is supported by a unit support member 3 via rotation-permitting support parts 4, 4 at two upper and lower positions so as to be rotatable about a steering axis A extending in the vertical direction. It is The steering axis A is different from the rotation axis O of the front wheel 9F, and is also different from the kingpin axis for main steering. In a normal vehicle, the kingpin angle is set at 10 to 20 degrees for the purpose of improving the straight running stability of the vehicle. has a rudder shaft of The front wheel 9F has a wheel 9a and a tire 9b.

As shown in FIG. 1, the hub unit 1 (FIG. 2) steers the left and right front wheels 9F, 9F separately by a minute angle (approximately ±5 degrees) in addition to the steering of the left and right front wheels 9F by the first steering device 11. As a mechanism for allowing the suspension, the knuckle 6 of the suspension device 12 is integrally provided. The first steering device 11 is of the rack and pinion type, but any type of steering device may be used. The suspension system 12 employs, for example, a strut suspension mechanism that directly fixes the shock absorber to the knuckle 6, but a double wishbone suspension mechanism, a multi-link suspension mechanism, or other suspension mechanisms may also be applied. .

<Regarding the hub unit body 2>
As shown in FIG. 2, the hub unit main body 2 includes a hub bearing 15 for supporting the front wheel 9F, an outer ring 16, and an arm portion 17 (FIG. 4) as a steering force receiving portion described later.
As shown in FIG. 8, the hub bearing 15 has an inner ring 18, an outer ring 19, and rolling elements 20 such as balls interposed between the inner and outer rings 18, 19. 2) It plays a role of connecting with.

In the illustrated example, the hub bearing 15 is an angular contact ball bearing in which the outer ring 19 is a fixed ring, the inner ring 18 is a rotating ring, and the rolling elements 20 are double rows. The inner ring 18 has a hub ring portion 18a having a hub flange 18aa and forming an outboard side raceway surface, and an inner ring portion 18b forming an inboard side raceway surface. As shown in FIG. 2, the wheel 9a of the front wheel 9F is bolted to the hub flange 18aa so as to overlap the brake rotor 21a. The inner ring 18 rotates around the rotation axis O.

As shown in FIG. 8, the outer ring 16 includes an annular portion 16a fitted to the outer peripheral surface of the outer ring 19, and a trunnion-shaft-shaped mounting shaft portion protruding vertically from the outer periphery of the annular portion 16a. 16b, 16b. Each mounting shaft portion 16b is provided coaxially with the turning axis A. As shown in FIG.
As shown in FIG. 3, the brake 21 has a brake rotor 21a and a brake caliper 21b. The brake caliper 21b is attached to two upper and lower brake caliper attachment portions 22 (FIG. 6) formed integrally with the outer ring 19 so as to protrude in the form of arms.

<Regarding rotation-permitting support parts and unit support members>
As shown in FIG. 8, each rotation-permitting support component 4 consists of a rolling bearing. In this example, tapered roller bearings are used as rolling bearings. The rolling bearing has an inner ring 4a fitted to the outer circumference of the mounting shaft portion 16b, an outer ring 4b fitted to the unit support member 3, and a plurality of rolling elements 4c interposed between the inner and outer rings 4a and 4b.

The unit support member 3 has a unit support member main body 3A and a unit support member combined body 3B. A substantially ring-shaped unit support member assembly 3B is detachably fixed to the outboard side end of the unit support member main body 3A. Partial concave spherical fitting hole forming portions 3a are formed in the upper and lower portions of the inboard-side side surface of the unit support member combined body 3B.

As shown in FIGS. 7 and 8, the upper and lower portions of the outboard side end of the unit support member main body 3A are formed with partially concave spherical fitting hole forming portions 3Aa. As shown in FIGS. 4 and 5, a unit support member assembly 3B is fixed to the outboard side end of the unit support member main body 3A, and fitting hole forming portions 3a and 3Aa (FIG. 7) are provided for each upper and lower portion. By being combined with each other, a fitting hole extending along the entire circumference is formed. The outer ring 4b (FIG. 8) is fitted into this fitting hole. In addition, in FIG. 4, the unit support member 3 is represented by a dashed line.

As shown in FIG. 8, each mounting shaft portion 16b of the outer ring 16 is formed with a female thread extending in the radial direction, and a bolt 23 screwed into the female thread is provided. A disk-shaped pressing member 24 is interposed on the end surface of the inner ring 4a, and a bolt 23 screwed into the female thread portion applies a pressing force to the end surface of the inner ring 4a, thereby preloading each rotation-allowing support member 4. giving. Thereby, the rigidity of each rotation-permitting support component 4 can be increased. It is set so that the initial preload is not lost even when the weight of the vehicle acts on this hub unit. The rolling bearing of the rotation-permitting support component 4 is not limited to a tapered roller bearing, and an angular contact ball bearing can be used depending on usage conditions such as maximum load. Also in that case, preload can be applied in the same manner as described above.

As shown in FIG. 3, the arm portion 17 is a portion that acts as a point of application of a steering force to the outer ring 19 of the hub bearing 15, and is integrated with a portion of the outer circumference of the annular portion 16a or a portion of the outer circumference of the outer ring 19. protrude to The arm portion 17 is rotatably connected to the direct-acting output portion 25 a of the steering actuator 5 via the joint portion 8 . As a result, the direct-acting output portion 25a of the steering actuator 5 advances and retreats, so that the hub unit main body 2 rotates about the steering axis A (FIG. 2), that is, is steered.

<Regarding the steering actuator 5>
As shown in FIG. 3, the steering actuator 5 has an actuator body 7 that rotates the hub unit body 2 around the turning axis A (FIG. 2). The actuator main body 7 includes a motor 26, a speed reducer 27 that reduces the rotation of the motor 26, and a linear motion mechanism 25 that converts the forward and reverse rotation output of the speed reducer 27 into reciprocating linear motion of a linear motion output section 25a. Prepare. The motor 26 is, for example, a permanent magnet type synchronous motor, but may be a DC motor or an induction motor.

The speed reducer 27 can use a winding type transmission mechanism such as a belt transmission mechanism, a gear train, or the like, and the belt transmission mechanism is used in the example of FIG. The speed reducer 27 has a drive pulley 27a, a driven pulley 27b, and a belt 27c. A drive pulley 27a is coupled to the motor shaft of the motor 26, and the linear motion mechanism 25 is provided with a driven pulley 27b. The driven pulley 27b is arranged parallel to the motor shaft. The driving force of the motor 26 is transmitted from the drive pulley 27a to the driven pulley 27b via the belt 27c. The drive pulley 27a, the driven pulley 27b, and the belt 27c constitute a winding-type speed reducer 27. As shown in FIG.

The linear motion mechanism 25 can use a feed screw mechanism such as a slide screw or ball screw, or a rack and pinion mechanism, etc. In this example, a feed screw mechanism (reverse input prevention mechanism) 25b using a trapezoidal slide screw. is used. Since the linear motion mechanism 25 includes the feed screw mechanism 25b using the slide screw of the trapezoidal screw, the effect of preventing reverse input from the tire 9b can be enhanced. A reverse input prevention mechanism such as a worm gear may be employed instead of the feed screw mechanism 25b using the slide screw of the trapezoidal screw. The actuator main body 7 including the motor 26, the speed reducer 27, and the linear motion mechanism 25 is assembled as a sub-assembly and detachably attached to the case 6b with bolts or the like. A mechanism is also possible in which the driving force of the motor 26 is directly transmitted to the direct acting mechanism 25 without using a speed reducer.

As a part of the unit support member 3, the case 6b is formed integrally with the unit support member main body 3A. The case 6b is formed in a cylindrical shape with a bottom, and is provided with a motor accommodating portion that supports the motor 26 and a linear motion mechanism accommodating portion that supports the linear motion mechanism 25 . A fitting hole for supporting the motor 26 at a predetermined position inside the case is formed in the motor accommodating portion. A fitting hole for supporting the linear motion mechanism 25 at a predetermined position in the case, a through hole for allowing the linear motion output portion 25a to advance and retreat, and the like are formed in the linear motion mechanism accommodating portion.

As shown in FIG. 4, the unit support member main body 3A includes the case 6b, a shock absorber mounting portion 6c which is a shock absorber mounting portion, and a steering device coupling portion which is a coupling portion for the first steering device 11 (FIG. 3). It has a portion 6d. The shock absorber attachment portion 6c and the steering device coupling portion 6d are also formed integrally with the unit support member main body 3A. A shock absorber attachment portion 6c is formed so as to protrude from the upper portion of the outer surface portion of the unit support member main body 3A. A steering device connecting portion 6d is formed so as to protrude from the side portion of the outer surface portion of the unit support member main body 3A.

<Configuration of Vehicle Information Detection Unit 110>
As shown in FIG. 9 , vehicle information detection unit 110 detects vehicle information and outputs it to ECU 130 . Vehicle information detector 110 includes vehicle speed detector 111 , steering angle detector 112 , vehicle height detector 113 , actual yaw rate detector 114 , actual lateral acceleration detector 115 , accelerator pedal sensor 116 , and brake pedal sensor 117 .

The vehicle speed detection unit 111 detects the speed of the vehicle (vehicle speed) based on the output of a sensor (not shown) such as a speed sensor attached inside the transmission provided in the vehicle, and sends vehicle speed information (simply “ (also called "vehicle speed") is output.
The steering angle detection unit 112 detects the steering angle based on the output of a sensor (not shown) such as a resolver attached to the motor unit included in the first steering device 11, and sends the steering angle information (simply " (also called "steering angle") is output.

Vehicle height detection unit 113 detects the distance between the chassis of vehicle 100 (FIG. 1) and the ground using a laser displacement meter, or detects the upper arm (not shown) of suspension system 12 (FIG. 1) of vehicle 100 (FIG. 1). Alternatively, the vehicle height of each front wheel 9F (FIG. 1) steered by the second steering device 150 is detected by a method of detecting the angle of the lower arm with an angle sensor. Then, vehicle height detection unit 113 outputs the detected vehicle height to ECU 130 as vehicle height information (also simply referred to as “vehicle height”).

The actual yaw rate detection unit 114 detects the actual yaw rate based on the output of a sensor such as a gyro sensor attached to the vehicle 100 (FIG. 1), and provides the actual yaw rate information (simply referred to as "actual yaw rate") to the ECU 130. Output.
The actual lateral acceleration detection unit 115 detects the actual lateral acceleration based on the output of a sensor such as a gyro sensor attached to the vehicle 100 (FIG. 1), and provides the ECU 130 with actual lateral acceleration information (simply called "actual lateral acceleration"). ) is output.

Accelerator pedal sensor 116 detects an input to accelerator pedal 210 by the driver and outputs the detected value to ECU 130 as an accelerator command value.
Brake pedal sensor 117 detects an input to brake pedal 220 by the driver and outputs the detected value to ECU 130 as a brake command value.
The ECU 130 outputs this vehicle information to the control section 150b of the second steering device 150. FIG.

<Control Unit 150b of Second Steering Device 150>
The control unit 150b of the second steering device 150 acquires vehicle information including vehicle speed information, steering angle information, vehicle height information, actual yaw rate information, actual lateral acceleration information, accelerator command value, and brake command value from the ECU 130. Based on the acquired vehicle information, the steering control unit 151 controls the right wheel actuator control device 31R and the left wheel actuator control device 31L to operate the motors 26 provided in the right wheel hub unit 1R and the left wheel hub unit 1L. The left and right wheels, which are the left and right front wheels, can be independently steered.

In the control unit 150b, the relationship between each information such as the steering angle, which is the vehicle information, and the command value for driving the motor 26 is defined as a control rule using, for example, a map or an arithmetic expression. is used for control.
The control unit 150b is provided as a dedicated ECU, for example, but may be provided as a part of the main ECU 130. FIG.

As shown in FIG. 10 , the main power source Bm and the sub power source Bs supply power to the second steering device 150 . As the main power supply Bm, for example, a battery (for example, a 12V battery) of the vehicle 100 (FIG. 1) on which the steering system 101 (FIG. 1) is mounted can be applied. The sub power source Bs has a right wheel backup power source Bsa and a left wheel backup power source Bsb. A secondary battery is generally used as each of the backup power sources Bsa and Bsb, but a capacitor or capacitors may also be used. Among the above capacitors, it is particularly preferable to use electrolytic capacitors or electric double-layer capacitors because of their relatively large capacity per volume.

The right wheel actuator control device 31R includes a left wheel abnormality detection section 221, and the left wheel actuator control device 31L includes a right wheel abnormality detection section 222. FIG. One abnormality detection unit 221 (222) of the left and right wheel abnormality detection units 221 and 222 detects an abnormality in the corresponding electric power system 223R (223L) and transmits the abnormality detection information to the left and right wheel abnormality detection units 221 and 222. 222 has a mutual monitoring function to provide mutual monitoring to the other abnormality detection unit 222 (221) in 222 .

When an abnormality occurs in the electric power system 223R supplied from the main power source Bm to the right wheel actuator control device 31R, the abnormality is detected by the left wheel abnormality detection section 221, and the left wheel abnormality detection section 221 detects the abnormality detection information. It is supplied to the abnormality detection section 222 of the right wheel. The left wheel actuator control device 31L supplied with the abnormality detection information supplies electric power from the right wheel backup power supply Bsa to the right wheel actuator control device 31R instead of the abnormal power system 223R.
When an abnormality occurs in the electric power system 223L supplied from the main power supply Bm to the left wheel actuator control device 31L, the abnormality is detected by the right wheel abnormality detection section 222, and the right wheel abnormality detection section 222 detects the abnormality detection information. It is supplied to the abnormality detection section 221 for the left wheel. The right wheel actuator control device 31R supplied with the abnormality detection information supplies power from the left wheel backup power supply Bsb to the left wheel actuator control device 31L instead of the power system 223L having the abnormality.

Abnormality of each electric power system 223R, 223L is, for example, disconnection of an electric cable connected from the main power supply Bm to the corresponding actuator control device 31R (31L), overcurrent flowing in this electric cable, or the like. Each of the abnormality detection units 221 and 222 includes, for example, a current sensor or the like. It is detected that 223R and 223L are abnormal.

The actuator control devices 31L and 31R for the left and right wheels determine the toe angles of the left and right wheels when the abnormality detection information is given from one of the abnormality detection sections 221 (222) to the other abnormality detection section 222 (221). After controlling each steering actuator 5 (FIG. 2) so that it operates to the reference value, this control is stopped. The predetermined reference value is, for example, a toe-in state in which the toe angle is a small angle or a toe angle initial state in which the toe angle is 0 degree. Each backup power source Bsa, Bsb may be provided as a part of the components of the second steering device 150 .

<Flowchart>
FIG. 11 is a flow chart showing step by step the process when an abnormality occurs in the power system. The description will be made with reference to FIGS. 9 and 10 as appropriate. While the vehicle is running, the left and right wheel abnormality detection units 221 and 222 detect whether or not there is an abnormality in each of the electric power systems 223R and 223L (step S1). When there is no abnormality in each power system 223R, 223L (step S1: No), the process returns to step S1. In this case, power is supplied from the main power supply Bm to the left and right wheel actuator control devices 31L and 31R, respectively. When an abnormality occurs in one of the electric power systems 223R, 223L (step S1: Yes), the actuator control devices 31R, 31L provided with the abnormality detection information switch from the main power supply Bm to the corresponding backup power supply Bsa, Bsb (step S2).

Next, the left and right wheel actuator controllers 31L and 31R symmetrically steer the left and right front wheels to 0 degrees or toe-in, which is the initial state of the toe angle, by the left and right wheel hub units 1L and 1R (step S3). The control unit 150b calculates the corrected steering amount of each steering actuator 5 (FIG. 2), that is, the current to be supplied to each motor 26 (step S4), and then drives each steering actuator 5 (FIG. 2) (step S5). . When the control unit 150b determines that the toe angle is in the initial state from the steering angles detected by the left and right wheel steering angle sensors S _L and S _R (step S6: Yes), this processing ends. When the steering has not reached the toe angle initial state (step S6: No), the process returns to step S5.

In addition to the above-described processing when an abnormality occurs in the electric power system, the steering control unit 151 performs control to independently steer the left and right wheels as shown in FIG. 12 . The control shown in FIG. 12 and the control shown in FIG. 11 etc. may be switched according to the operation of the driver or the vehicle condition, or may be executed in parallel.
As shown in FIG. 12, the steering control unit 151 includes a reference lateral acceleration calculation unit 152, a right wheel tire angle calculation unit 153, a left wheel tire angle calculation unit 154, a right wheel road surface friction coefficient calculation unit 155, a target yaw rate calculation unit 156, A left wheel road surface friction coefficient calculator 157 , a target yaw rate corrector 158 , a target right and left wheel tire angle calculator 159 , a right wheel command value calculator 160 , and a left wheel command value calculator 161 are provided.

Right wheel tire angle calculation unit 153 and left wheel tire angle calculation unit 154 acquire steering angle information and vehicle height information from ECU 130 at a predetermined cycle. The right tire angle calculation unit 153 and the left tire angle calculation unit 154 calculate the current angle of the tire that is steered by the second steering device 150 (FIG. 9) based on the acquired steering angle information and vehicle height information. and outputs the calculated tire angle information to standard lateral acceleration calculator 152 .

The standard lateral acceleration calculator 152 calculates standard lateral acceleration based on the vehicle speed information and the tire angle information acquired from the ECU 130 . Standard lateral acceleration calculator 152 outputs the calculated standard lateral acceleration as standard lateral acceleration information to right wheel road surface friction coefficient calculator 155 and left wheel road surface friction coefficient calculator 157 .

FIG. 13 is a diagram showing a map for calculating the road surface friction coefficient, and this map is stored in the right wheel road surface friction coefficient calculation unit 155 and the left wheel road surface friction coefficient calculation unit 157 shown in FIG.
A right wheel road surface friction coefficient calculation unit 155 and a left wheel road surface friction coefficient calculation unit 157 calculate the road surface friction coefficient based on the actual lateral acceleration information obtained from the ECU 130 and the standard lateral acceleration information input from the standard lateral acceleration calculation unit 152. I do. Specifically, when standard lateral acceleration information is input from standard lateral acceleration calculation unit 152, right wheel road surface friction coefficient calculation unit 155 and left wheel road surface friction coefficient calculation unit 157 calculate right wheel tire angle calculation unit 153 and left wheel tire angle calculation unit 157, respectively. Tire angle information is acquired from the angle calculator 154 . The right wheel road surface friction coefficient calculation unit 155 and the left wheel road surface friction coefficient calculation unit 157 calculate the road surface friction coefficient from the actual lateral acceleration/standard lateral acceleration and the tire angle based on the map (FIG. 13). The right wheel road surface friction coefficient calculation unit 155 and the left wheel road surface friction coefficient calculation unit 157 calculate right wheel road surface friction coefficient information, which is the calculated right wheel road surface friction coefficient, and left wheel road surface friction coefficient information, which is the calculated left wheel road surface friction coefficient. , to the target yaw rate correction unit 158 .

Target yaw rate calculation unit 156 calculates a target yaw rate based on vehicle speed information and steering angle information obtained from ECU 130 at predetermined intervals, and outputs the calculated target yaw rate to target yaw rate correction unit 158 as target yaw rate information.
Target yaw rate correction unit 158 acquires right wheel road surface friction coefficient information and left wheel road surface friction coefficient information from right wheel road surface friction coefficient calculation unit 155 and left wheel road surface friction coefficient calculation unit 157, and obtains target yaw rate information from target yaw rate calculation unit 156. is obtained, and the target yaw rate is corrected according to the road friction coefficient represented by the right wheel road friction coefficient information and the left wheel road friction coefficient information. Target yaw rate correction section 158 outputs the target yaw rate after correction to target left and right wheel tire angle calculation section 159 as corrected yaw rate information.

Target right and left wheel tire angle calculation section 159 receives corrected yaw rate information from target yaw rate correction section 158, actual yaw rate information, accelerator command value and brake command value from ECU 130, and right wheel road friction coefficient from right wheel road surface friction coefficient calculation section 155. Left wheel road surface friction coefficient information is obtained from coefficient information and left wheel road surface friction coefficient calculation unit 157, and target left and right wheel tire angles, which are target values for right and left wheel tire angles, are calculated. Specifically, the target left and right wheel tire angle calculation unit 159 calculates the target angles of the left and right tires based on the following formula (1).

In equation (1), _θy is the actual yaw rate of the vehicle represented by the actual yaw rate information, _XA is the accelerator command value, _XB is the brake command value, _μR is the right wheel road surface friction coefficient, and _μL is the left wheel A road surface friction coefficient, θ _tR1 is a right wheel target tire angle, and θ _tL1 is a left wheel target tire angle.
Target left and right wheel tire angle calculation unit 159 outputs the calculated target tire angles of the left and right wheels to right wheel command value calculation unit 160 and left wheel command value calculation unit 161 as target tire angle information.

The right wheel command value calculation unit 160 and the left wheel command value calculation unit 161 acquire the target tire angle information, respectively, and calculate the current tire angle from the right wheel tire angle calculation unit 153 and the left wheel tire angle calculation unit 154. Angle information is acquired, and the target tire angle represented by the target tire angle information is compared with the current tire angle. Right wheel command value calculation unit 160 and left wheel command value calculation unit 161 indicate the amount of steering of right wheel hub unit 1R and left wheel hub unit 1L, respectively, according to the amount of deviation between the target tire angle and the current tire angle. Right wheel steering amount information and left wheel steering amount information are generated. The right wheel command value calculation unit 160 outputs the generated right wheel steering amount information (current command signal) to the left and right wheel actuator control devices 31L and 31R. The left wheel command value calculation unit 161 outputs the generated left wheel steering amount information (current command signal) to the left and right wheel actuator control devices 31L and 31R.

Each actuator control device 31R, 31L has an inverter (not shown). The right wheel actuator control device 31R and the left wheel actuator control device 31L control the current to the motor 26 of each steering actuator based on the right wheel steering amount information and the left wheel steering amount information.
Specifically, as shown in FIGS. 9 and 12, the right wheel actuator control device 31R and the left wheel actuator control device 31L receive the right wheel steering amount from the right wheel command value calculation unit 160 and the left wheel command value calculation unit 161. When the information and the left wheel steering amount information are input, the position information of each motor 26 indicating the current steering angle of the right wheel hub unit 1R and the left wheel hub unit 1L is acquired, and the right wheel steering amount information and the left wheel steering amount information are obtained. , the current to be supplied to each motor 26 is output, and the steering angles of the right wheel hub unit 1R and the left wheel hub unit 1L are corrected. Steering angle information of the right wheel hub unit _1R and the left wheel hub unit 1L is output to the steering control unit 151 from the right wheel steering angle sensor SR and the left wheel steering angle sensor _SL .

As shown in FIG. 4, each actuator control device 31R, 31L outputs a current corresponding to a current command signal input from the steering control section 151 to drive and control the steering actuator 5. FIG. Actuator controllers 31R and 31L control the power supplied to the coils of motor 26. FIG. The actuator control devices 31R and 31L constitute, for example, a half bridge circuit using switch elements (not shown), and perform PWM control for determining the voltage applied to the motor according to the ON-OFF duty ratio of the switch elements. As a result, the angle of the wheels can be slightly changed in addition to the steering by the steering wheel operation of the driver. Even during straight running, the toe angle can be adjusted according to the vehicle speed and the like.

<Effect>
According to the steering system 101 described above, by providing the second steering device 150, it is possible to correct the steering without operating the steering wheel. That is, in conventional vehicles, when the vehicle sways slightly, the driver has to perform corrective steering to correct the swaying. It is possible to correct the swaying of the vehicle without performing the operation of . Therefore, the straight running stability of the vehicle is improved.
When cornering, the driver's steering operation is corrected according to the vehicle information so that the steering amount of each of the left and right wheels is corrected so that the vehicle can turn more efficiently. Since the operation load can be reduced, the steering stability of the vehicle can be improved.

Since the left and right wheel actuator control devices 31L and 31R are provided with left and right wheel abnormality detection units 221 and 222 having a mutual monitoring function, a power system 223R ( 223L), one abnormality detection section 221 (222) in one actuator control device 31R (31L) gives abnormality occurrence information to the other abnormality detection section 222 (221). The other actuator control device 31L (31R) provided with the other abnormality detection unit 222 (221) to which the abnormality occurrence information is supplied, replaces the abnormal electric power system 223R (223L) with the auxiliary power supply Bs to the one actuator. Power is supplied to the controller 31R (31L). After that, the toe angles of the left and right wheels are set to their respective reference values, and the motor control is stopped. If the toe angles of the left and right wheels are returned to a predetermined reference value, and reverse input from the road surface is prevented by the feed screw mechanism 25b using a slide screw such as a trapezoidal screw, the hub unit 1 will not wobble when the control is stopped. Safety can be ensured by moving the vehicle to a state where it can be reliably stopped by the steering wheel operation of the driver.

<About other embodiments>
In the following description, the same reference numerals are given to the parts corresponding to the items previously described in each embodiment, and duplicate descriptions are omitted. When only a portion of the configuration is described, the other portions of the configuration are the same as those previously described unless otherwise specified. The same configuration has the same effect. It is possible not only to combine the parts specifically described in each embodiment, but also to partially combine the embodiments if there is no particular problem with the combination.

[Second embodiment]
A second embodiment of the invention will be described with reference to FIGS. 14 to 16. FIG.
As shown in FIG. 14, the steering system 101 according to the second embodiment differs from the first embodiment in that the first steering device 11 and the second steering device 150 steer different wheels. different. That is, the steering system 101 steers the left and right front wheels 9F, 9F, and the second steering device 150 steers the left and right rear wheels 9R, 9R. The mechanical portion 150a of the second steering device 150 is installed inside the tire housing 105 of the rear wheel 9R.

As shown in FIGS. 15 and 16, the steering control unit 151 in the control unit 150b acquires the vehicle speed, steering angle, actual yaw rate, actual lateral acceleration, accelerator command value, and brake command value as vehicle information from the ECU 130. It controls the right wheel actuator control device 31R and the left wheel actuator control device 31L.
Then, the target left and right wheel tire angle calculation unit 159 of the steering control unit 151 calculates the target angles of the left and right tires based on the following equation (2).

In equation (2), θ _HR is the steering angle of the right front wheel, θ _HL is the steering angle of the left front wheel, μ _HR is the friction coefficient between the right front wheel and the road surface, and μ _HL is the friction coefficient between the left front wheel and the road surface. Other terms are the same as those described in formula (1).
Even when the first steering device 11 and the second steering device 150 steer different wheels, the second steering device 150 steers the steering wheel according to the steering angle of the first steering device 11 and the vehicle speed. It is possible to steer the vehicle and improve the running stability of the vehicle.

Also in the second embodiment, as in the first embodiment, when an abnormality occurs in the electric power system supplied from the main power supply Bm (FIG. 10) to one actuator control device 31R (31L), one actuator One abnormality detection section 221 (222) in the control device 31R (31L) provides abnormality occurrence information to the other abnormality detection section 222 (221). The other actuator control device 31L (31R), which is provided with the other abnormality detection unit 222 (221) to which the abnormality occurrence information is supplied, replaces the power system with the abnormality with the auxiliary power supply Bs (FIG. 10) to the one actuator. Power is supplied to the controller 31R (31L). After that, the toe angles of the left and right wheels are set to their respective reference values, and the motor control is stopped. If the toe angles of the left and right wheels are returned to a predetermined reference value, and reverse input from the road surface is prevented by the feed screw mechanism 25b (Fig. 3) using a slide screw such as a trapezoidal screw, the hub unit can be operated in a state where control is stopped. swaying can be prevented, and safety can be ensured by moving the vehicle to a state in which the vehicle can be reliably stopped by operating the steering wheel of the driver.

[Third Embodiment]
A third embodiment of the invention will be described with reference to FIGS. 17 and 18. FIG.
A steering system 101 according to the third embodiment differs from the first embodiment in that it includes two second steering devices 150 ₁ and 150 ₂ .
One second steering device _150-1 performs the same operation as the second steering device 150 of the first embodiment, and the other second steering device _150-2 operates like the second steering device 150-2 of the second embodiment. It performs the same operation as the steering device 150 .

According to this steering system 101, by including a plurality of (two in this example) second steering devices 150 ₁ and 150 ₂ , it is possible to steer the four wheels independently in a more complicated manner. It is possible to improve the running stability of the vehicle 100 .
Further, as in the first and second embodiments, when an abnormality occurs in the power system supplied from the main power supply Bm (FIG. 10) to one of the actuator control devices, one of the actuator control devices detects an abnormality. The section gives the abnormality occurrence information to the other abnormality detection section. The other actuator control device provided with the other abnormality detection unit to which the abnormality occurrence information is supplied supplies power from the auxiliary power supply to the one actuator control device instead of the power system with the abnormality. After that, the toe angles of the left and right wheels are set to their respective reference values, and the motor control is stopped. If the toe angles of the left and right wheels are returned to a predetermined reference value, and reverse input from the road surface is prevented by the feed screw mechanism 25b (Fig. 3) using a slide screw such as a trapezoidal screw, the hub unit can be operated in a state where control is stopped. swaying can be prevented, and safety can be ensured by moving the vehicle to a state in which the vehicle can be reliably stopped by operating the steering wheel of the driver.

In each embodiment, when an abnormality occurs in the electric power system, control is performed so that the toe angles of the left and right wheels are adjusted to respective predetermined reference values and the motor control is stopped, but the control is not limited to this. . For example, in the actuator control device for the left and right wheels, when abnormality detection information is supplied from one abnormality detection section to the other abnormality detection section, power is supplied from the auxiliary power supply to the actuator control device having one abnormality detection section. Control of the steering actuator may continue.
In this case, even if an abnormality occurs in one of the electric power systems, the second steering device can steer the left and right wheels individually and adjust the toe angles of the left and right wheels individually and continuously. is.

In each of the above embodiments, the steering command device 200 is a steering wheel, but a manual steering command device other than the steering wheel, such as a joystick, or an automatic steering command device such as that shown in FIG. It may be 200A. The automatic steering command device 200A is a device that recognizes the vehicle surrounding conditions and the like from the vehicle surrounding condition detection means 230 and automatically generates a steering command. The vehicle surrounding situation detection means 230 is, for example, sensors such as a camera or a millimeter wave radar.

The automatic steering command device 200A recognizes, for example, white lines and obstacles on the road, and generates and outputs a steering command. The automatic steering command device 200A may be a part of a device for automatically driving a vehicle, or may be a device for assisting steering by manual driving. Even in a vehicle equipped with such a steering command device 200A that automatically generates a steering command, by providing the second steering device 150, operations that cannot be performed by the first steering device 11, such as toe angle control, can be performed. Further, it is also possible to perform the main steering in the running direction of the vehicle by the first steering device 11 and to perform the correction by the second steering device 150, so that the direction of the vehicle can be corrected in response to the steering amount command. As a result, it becomes possible to maintain the running stability of the vehicle.

As mentioned above, although the form for implementing this invention was demonstrated based on embodiment, embodiment disclosed this time is an illustration and is not restrictive at all points. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

REFERENCE SIGNS LIST 1 hub unit with steering function, 2 hub unit body, 3 unit support member, 5 steering actuator, 6 knuckle (undercarriage frame part), 9F front wheel, 9R rear wheel, 11 first wheel Steering device 12 Suspension device 15 Hub bearing 31L, 31R Left and right wheel actuator control device 100 Vehicle 101 Steering system 110 Vehicle information detector 150 Second steering device 200 Steering command device 221 Left wheel abnormality detector 222 Right wheel abnormality detector 223R, 223L Power system Bm Main power supply Bs Sub power supply

Claims (12)

A steering system provided in a vehicle,
a first steering device that steers left and right front wheels of the vehicle according to a steering amount command output by a steering command device;
In addition to the steering of the left and right front wheels by the first steering device, a second steering device for individually steering either one or both of the front and rear wheels by driving a steering actuator provided on the vehicle. a steering device;
a main power supply and a sub power supply that supply power to the second steering device;
A vehicle information detection unit that detects vehicle information representing the state of the vehicle,
The second steering device steers the left and right wheels by individually controlling the steering actuators for the left and right wheels based on the vehicle information including the steering angles of the left and right wheels. with an actuator controller of
The left and right wheel actuator controllers include right and left wheel abnormality detectors for detecting whether or not there is an abnormality in each electric power system supplied from the main power source to each of the actuator controllers. One of the abnormality detection units in the detection unit has a mutual monitoring function of providing abnormality detection information to the other abnormality detection unit of the left and right wheel abnormality detection units when an abnormality in the corresponding power system is detected,
supplying electric power from the main power supply to the actuator control devices for the left and right wheels respectively when there is no abnormality in the electric power system by the abnormality detection unit for the left and right wheels;
When the abnormality detection information is provided from one of the abnormality detection sections for the left and right wheels to the other abnormality detection section for the left and right wheels, instead of the power system having the abnormality, the auxiliary power supply: A steering system that supplies electric power to an actuator control device that includes the one abnormality detection unit. 2. The steering system according to claim 1, wherein the first steering device steers the left and right front wheels in conjunction with each other, and the second steering device steers the left and right wheels independently. steering system possible. 3. The steering system according to claim 1, wherein said first and second steering devices steer said front wheels, which are the same wheels. 4. The steering system according to claim 1, wherein the vehicle information includes vehicle speed, steering angle, vehicle height, actual yaw rate, actual lateral acceleration, accelerator command value and brake command value. steering system. 3. The steering system according to claim 1, wherein said first steering device and said second steering device steer wheels different from each other. 6. The steering system according to claim 5, wherein said vehicle information includes vehicle speed, steering angle, actual yaw rate, actual lateral acceleration, accelerator command value and brake command value. The steering system according to claim 1 or 2, comprising two second steering devices,
The second steering device on one side and the first steering device steer the same wheels,
The second steering device on the other side and the first steering device are steering systems that steer wheels different from each other. 8. The steering system according to any one of claims 1 to 7, wherein the actuator control device for the left and right wheels is provided with abnormality detection information from one abnormality detection section to the other abnormality detection section, A steering system in which power is supplied from the auxiliary power supply to an actuator control device having the one abnormality detection unit to continue control of the steering actuator. 8. The steering system according to any one of claims 1 to 7, wherein the actuator control device for the left and right wheels is provided with abnormality detection information from one abnormality detection section to the other abnormality detection section, A steering system that controls each of the steering actuators so as to return the toe angles of the left and right wheels to predetermined reference values. 10. The steering system according to any one of claims 1 to 9, wherein a secondary battery, a capacitor, or a capacitor is used as the auxiliary power supply. The steering system according to any one of claims 1 to 10, wherein the second steering device comprises:
a hub unit body having a hub bearing that supports a wheel;
a unit support member provided in a suspension frame part of a suspension system for supporting the hub unit body rotatably about a steering shaft extending in the vertical direction; and rotating the hub unit body about the steering shaft. A steering system using a hub unit with a steering function, which includes a steering actuator. A vehicle comprising the steering system according to any one of claims 1 to 11.

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