JP2020097257A - Steering system and vehicle having the same - Google Patents

Abstract

To provide a steering system and vehicle having the same, capable of improving running stability of a vehicle and maintaining followability to an operation of a steering wheel or the like even when some failure occurs in a power system.SOLUTION: A second steering device 150 of a steering system includes actuator controllers 31 L, 31R of left and right wheels for individually controlling a steering actuator. The actuator controllers 31L, 31R of left and right wheels include failure detection parts 221, 222 detecting whether some failure exist in respective power systems 223R, 223L from a main power supply Bm. One of the failure detection parts mutually gives failure detection information to the other failure detection part upon detection of some failure in the power system. In this case, electric power is supplied, in place of the failed power system, to the actuator controller with one failure detection part from a sub power supply Bs.SELECTED DRAWING: Figure 10

Description

The present invention relates to a steering system and a vehicle including the same, and relates to a technique 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 to each other, and the steering device steers wheels by rotating 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 that the steering wheel is taken by the reverse input from the wheels due to the unevenness of the road surface and the vehicle becomes unstable.
In addition, during cornering, there is a problem that running stability and followability to steering wheel operation deteriorate due to variations in the driver's proficiency level or environmental conditions such as the road surface.

JP, 2009-226972, A DE 102 01 2206 337 specification JP, 2014-061744, A JP, 2016-147513, A

In order to solve the above-mentioned problem, the steering direction of the vehicle is corrected by changing the angle of each of the left and right tires with respect to the first steering device that controls the steering angle by the driver's steering operation. Provided is a second steering device capable of improving the property and the like.
However, the second steering device, when an abnormality occurs in either one of the power systems or both of the power systems during the control during traveling of the vehicle, the direction of the tire is fixed in the direction when the power system is abnormal. Therefore, there is a problem that the handle operation becomes difficult.

An object of the present invention is to improve a running stability of a vehicle and to maintain a followability to a steering wheel operation and the like even when an abnormality occurs in a power system, and a vehicle including the steering system. Is to provide.

A steering system 101 of the present invention is a steering system included in a vehicle 100,
A first steering device 11 for steering the left and right front wheels 9F, 9F of the vehicle 100 in accordance with a steering amount command output from the steering command devices 200, 200A;
A second steering device 150 that individually steers one or both of the front and rear wheels by driving the steering actuator 5 provided in the vehicle 100;
A main power supply Bm and a sub power supply Bs for supplying electric power to the second steering device 150,
A vehicle information detection unit 110 that detects vehicle information indicating the state of the vehicle,
The second steering device 150 individually controls the steering actuators 5 of the other left and right wheels based on the vehicle information including the steering angle of one of the left and right wheels. Equipped with actuator control devices 31L and 31R of
The left and right wheel actuator control devices 31L and 31R detect whether or not the power systems 223R and 223L supplied from the main power source Bm to the respective actuator control devices 31R and 31L have a problem. The left and right wheel abnormality detection sections 221 and 222 include one of the left and right wheel abnormality detection sections 221 and 222, and when the abnormality detection section 221 detects a corresponding power system abnormality, the abnormality detection information is provided to the left and right wheel abnormality detection section 221. , 222 having a mutual monitoring function of giving each other to the other abnormality detecting section,
Electric power is supplied from the main power source Bm to the left and right wheel actuator control devices 31L and 31R, respectively, when there is no abnormality in any of the electric power systems by the left and right wheel abnormality detection units 221 and 222,
When abnormality detection information is given from one abnormality detection unit of the abnormality detection units 221 and 222 of the left and right wheels to the other abnormality detection unit of the abnormality detection unit of the left and right wheels, the sub-system is replaced with the abnormality in place of the power system having the abnormality. Electric power is supplied from the power supply Bs to the actuator control device including the one abnormality detection unit.

According to this configuration, since the second steering device 150 is provided, when the vehicle 100 slightly wobbles, it is possible to correct the wobbling of the vehicle 100 without the driver operating the steering wheel. Therefore, the straight running stability of the vehicle 100 is improved.
At the time of cornering, the driver can operate the steering wheel according to the vehicle information, and by correcting the steering amount of each of the left and right wheels so that the vehicle can turn more efficiently, cornering is possible on the ideal line, and the steering wheel of the driver Since the operation load can be reduced, the steering stability of the vehicle 100 can be improved.

When there is no abnormality in any of the power systems 223R and 223L, power is supplied from the main power source Bm to the actuator control devices 31L and 31R for the left and right wheels, respectively.
Since the left and right wheel actuator control devices 31L and 31R are provided with the 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 actuator control device. One abnormality detection unit in one actuator control device gives abnormality occurrence information to the other abnormality detection unit. The other actuator control device including the other abnormality detection unit to which the abnormality occurrence information is given supplies electric power from the auxiliary power supply Bs to the one actuator control device instead of the power system having the abnormality.

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

The first steering device 11 may steer the left and right front wheels 9F, 9F in an interlocking manner, and the second steering device 150 may be capable of independently steering the left and right wheels. When the second steering device 150 can steer the left and right rear wheels 9R and 9R independently, the behavior of the vehicle is not only corrected by the left and right front wheels 9F and 9F, but also by the left and right rear wheels 9R and 9R. Since this can be supplemented, the vehicle can be appropriately controlled.

The first and second steering devices 11 and 150 may steer the front wheels 9F that are the same wheels. In this case, for example, in the high speed range, by changing the angles of the left and right front wheels 9F and 9F to set the parallel geometry, it is possible to make a smooth turn without increasing the 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 determines 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 individually calculate the respective tire angles for the left and right wheels for cornering the vehicle on an ideal line, and to individually drive the steering actuators 5 for the left and right wheels.

The first steering device 11 and the second steering device 150 may perform steering of different wheels. In this case, in the low speed range, the left and right wheel actuator control devices 31L and 31R steer only the front wheels by steering the left and right rear wheels 9R and 9R in opposite phases to the steering angles of the front wheels 9F and 9F. It is possible to further reduce the minimum turning radius. As a result, the turning performance of the vehicle can be improved.
In the high speed range, the actuator control devices 31L and 31R for the left and right wheels suppress the sideslip by steering the left and right rear wheels 9R and 9R in the same phase with respect to the steering angles of the front wheels 9F and 9F, thereby changing lanes. It is 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 states of the contact surfaces of 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 of the second steering devices 150 are provided,
One of the second steering device 150 ₁ and the first steering device 11 steers the same wheel,
And ₂ other of the second steering device 150, wherein the first steering device 11, may perform the steering of the different wheels from each other.
In this case, the angles of all the wheels can be independently adjusted according to the vehicle information, and the steering geometry can be freely changed, so that the dynamic performance of the vehicle can be improved.

When abnormality detection information is given from one abnormality detection unit to the other abnormality detection unit, the actuator control devices 31L and 31R for the left and right wheels change from the auxiliary power source Bs to an actuator control device including the one abnormality detection unit. The control of the steering actuator 5 may be continued by supplying electric power. In this case, even if an abnormality occurs in any of the electric power systems, the second steering device 150 can individually and continuously adjust the toe angles of the left and right wheels by individually steering the left and right wheels. It is possible.

When the abnormality detection information is given from one abnormality detection unit to the other abnormality detection unit, the left and right wheel actuator control devices 31L and 31R return the toe angles of the left and right wheels to the predetermined reference values. The actuator 5 may be controlled.
The defined reference value is a reference value arbitrarily determined by design or the like, and is determined by determining an appropriate reference value by one or both of a test and a simulation, for example.
In this case, since the steering actuators 5 are controlled so that the toe angles of the left and right wheels are returned to the predetermined reference values, the auxiliary power source Bs having a small capacity can be used and the steering system 101 can be downsized. Become.

A secondary battery, a capacitor, or a capacitor may be used as the sub power source Bs.

As the second steering device 150,
A hub unit main body 2 having a hub bearing 15 that supports wheels 9F (9R);
A unit support member 3 provided on the undercarriage frame component 6 of the suspension device 12 to rotatably support the hub unit body 2 around a steering axis A extending in the vertical direction, and the hub unit body 2 on the steering shaft. It is also possible to use the hub unit 1 with a steering function, which is provided with the steering actuator 5 that is driven to rotate around the center A.

With this configuration, the hub unit main body 2 including the hub bearing 15 that supports 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, the steering wheels or the non-steered wheels can be steered at a minute angle. Therefore, the steering geometry can be changed when the vehicle is turning, which improves the running stability of the vehicle. Even when driving straight, the amount of toe angle can be adjusted according to each situation, so that it is possible to make adjustments such as ensuring running stability at high speeds without lowering running resistance and worsening fuel consumption at low speeds.

The vehicle of the present invention includes the steering system 101 having any one of the above configurations of the present invention. Therefore, the above-described effects of the steering system of the present invention can be obtained.

A steering system of the present invention is a steering system provided in a vehicle, comprising: a first steering device that steers left and right front wheels of the vehicle in accordance with a steering amount command output from a steering command device; Second steering device for individually steering one of the front and rear wheels or both left and right wheels by driving an actuator for the vehicle, a main power supply and a sub power supply for supplying electric power to the second steering device, and And a vehicle information detection unit that detects vehicle information indicating a state, wherein the second steering device detects the left and right wheels based on the vehicle information including a steering angle of one of the left and right wheels. An actuator control device for the left and right wheels that individually controls the steering actuator for the other wheel is provided, and the actuator control device for the left and right wheels has an abnormality in each power system supplied from the main power supply to each actuator control device. The abnormality detection unit for the left and right wheels is provided to detect whether or not there is any abnormality, and one abnormality detection unit for the abnormality detection unit for the left and right wheels outputs the abnormality detection information when the abnormality in the corresponding power system is detected. A mutual abnormality monitoring function is provided to the other abnormality detection unit of the wheel abnormality detection unit, and when there is no abnormality in either power system by the abnormality detection unit of the left and right wheels, an actuator control device for the left and right wheels from the main power source. When the abnormality detection information is given from one abnormality detection section of the abnormality detection section of the left and right wheels to the other abnormality detection section of the abnormality detection section of the left and right wheels, the power system is replaced with the abnormality. Then, electric power is supplied from the sub power supply to the actuator control device including the one abnormality detection unit. Therefore, it is possible to improve the running stability of the vehicle, and it is possible to maintain the followability with respect to the steering wheel operation and the like even when an abnormality occurs in the power system.

Since the vehicle of the present invention is provided with the steering system having the above-mentioned configuration of the present invention, it is possible to improve the running stability of the vehicle and to follow the steering operation even when an abnormality occurs in the power system. Can be maintained.

It is a figure which shows roughly the conceptual structure of the steering system which concerns on the 1st Embodiment of this invention. FIG. 3 is a vertical cross-sectional view showing a configuration of a mechanical portion of a second steering device and its periphery in the steering system. It is a horizontal sectional view showing composition of a mechanical part etc. of the 2nd steering device. It is a perspective view showing the appearance of the mechanism part of the 2nd steering device. It is an exploded front view of the mechanism part of the 2nd steering device. It is a front view of the mechanism part of the 2nd steering device. It is a top view of the mechanism part of the 2nd steering device. FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 6. It is a block diagram showing a conceptual configuration of the steering system. It is a block diagram showing a conceptual configuration of the second steering device. It is a flow chart which shows processing in steps at the time of a power system abnormality occurrence. It is a block diagram showing the composition of the steering control part of the 2nd steering device. 6 is a graph showing an example of the relationship between the actual lateral acceleration/standard lateral acceleration, the tire angle, and the friction coefficient. It is a figure which shows roughly the conceptual structure of the steering system which concerns on the 2nd Embodiment of this invention. It is a block diagram showing a conceptual configuration of the steering system. It is a block diagram which shows the structure of the steering control part of the 2nd steering device of the same steering system. It is a figure which shows roughly the conceptual structure of the steering system which concerns on the 3rd Embodiment of this invention. It is a block diagram showing a conceptual configuration of the steering system.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram schematically showing a 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-wheel vehicle having left and right front wheels (left and right wheels) 9F and 9F and left and right rear wheels 9R and 9R. The drive system is either front wheel drive, rear wheel drive, or four wheel drive. May be.

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

The second steering device 150 is a device that performs auxiliary steering by control according to the state of the vehicle 100, and includes a mechanism unit 150a and a control unit 150b. The mechanical unit 150a is a mechanism provided for each of the front wheels 9F, 9F that are the target of auxiliary steering. The mechanism portion 150a is provided in the tire housing 105 of the vehicle 100 and individually steers the front wheels 9F by driving the steering actuator 5 (FIG. 2). The control unit 150b controls based on the vehicle information indicating the state of the vehicle 100 detected by the 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 from the steering command device 200. A first steering device 11 for steering by changing angles of knuckles 6, 6 which are left and right undercarriage frame parts of the suspension device 12,
By driving the steering actuators 5 (FIG. 2) provided respectively for the left and right front wheels 9F, 9F, the angles of the front wheels 9F, 9F with respect to the knuckles 6, 6 which are the undercarriage frame parts are changed to change the left and right front wheels. A second steering device 150 for individually steering 9F and 9F;
A vehicle information detection unit 110 described later,
A main power supply Bm and a sub power supply Bs for supplying electric 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. The vehicle information detected by the vehicle information detection unit 110 is transferred to the control unit 150b of the second steering device 150 via the main ECU 130.
The ECU 130 is a control device that performs cooperative control or overall control of the entire vehicle 100, and is also referred to as a VCU.

<Structure of the first steering device 11>
The first steering device 11 is a system that steers the left and right front wheels 9F, 9F in an interlocked manner in response to an input to a steering command device 200 such as a steering wheel by a driver, and includes a steering shaft 32 and a rack and pinion (not shown). No.), a well-known mechanical structure such as the tie rod 14 is provided. When the driver makes a rotation input to the steering command device 200, the steering shaft 32 also rotates in conjunction. When the steering shaft 32 rotates, the tie rods 14 connected to the steering shaft 32 by the rack and pinion move in the vehicle width direction, changing the direction of the front wheels 9F and steering the left and right front wheels 9F, 9F in an interlocking manner. It 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. A right wheel hub unit 1R and a left wheel hub unit 1L are provided as the mechanism portion 150a of the second steering device 150. The right wheel hub unit 1R and the left wheel hub unit 1L steer the front wheels 9F, 9F by the steering actuator 5 (FIG. 2) provided in the tire housing 105.

<Specific Configuration Example of Mechanism Unit 150a of Second Steering Device 150>
The mechanical section 150a of the second steering device 150 includes the right wheel hub unit 1R and the left wheel hub unit 1L as described above. The right wheel hub unit 1R and the left wheel hub unit 1L are both steering elements shown in FIG. It is configured as a functional hub unit 1.
As shown in FIG. 2, the hub unit 1 includes a hub unit body 2, a unit support member 3, a rotation permitting support component 4, and a steering actuator 5. The unit support member 3 is provided integrally with the knuckle 6 which is a suspension 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. With the hub unit 1 (FIG. 2) mounted on a vehicle, the vehicle width direction outer side of the vehicle is called the outboard side, and the vehicle width direction center side of the vehicle is called the inboard side.
As shown in FIGS. 3 and 4, the hub unit body 2 and the actuator body 7 are connected by a joint portion 8. Usually, a boot (not shown) is attached to the joint portion 8 for waterproofing and dustproofing.

As shown in FIG. 2, the hub unit main body 2 is supported by the unit support member 3 at two upper and lower positions via the rotation permitting support parts 4 and 4 so that the hub unit main body 2 is rotatable about a steering axis A extending in the vertical direction. Has been done. The steered shaft center A is a shaft center different from the rotation shaft center O of the front wheels 9F, and is also different from the kingpin shaft that mainly performs steering. In a normal vehicle, the kingpin angle is set to 10 to 20 degrees for the purpose of improving straight running stability of the vehicle, but the hub unit 1 of this embodiment has an angle (axis) different from the kingpin angle. It has a steering axis. The front wheel 9F includes a wheel 9a and a tire 9b.

As shown in FIG. 1, this hub unit 1 (FIG. 2) is added to the steering of the left and right front wheels 9F, 9F by the first steering device 11, and the left and right wheels are individually steered by a small angle (about ±5 deg). As a mechanism for this, it is provided integrally with the knuckle 6 of the suspension device 12. The first steering device 11 is a rack and pinion type, but any type of steering device may be used. For the suspension device 12, for example, a strut type suspension mechanism for directly fixing the shock absorber to the knuckle 6 is applied, but a double wishbone type suspension mechanism, a multi-link type suspension mechanism, or another suspension mechanism may be applied. ..

<About 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 wheels 9F, an outer ring 16, and an arm portion 17 (FIG. 4) which is 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 and 19, and a member on the vehicle body side and a front wheel 9F (see FIG. 2) Has a role of connecting with.

In the illustrated example, the hub bearing 15 is an angular 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 a raceway surface on the outboard side, and an inner ring portion 18b forming a raceway surface on the inboard side. 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 provided so as to vertically project from the outer periphery of the annular portion 16a. 16b and 16b. Each mounting shaft portion 16b is provided coaxially with the steering axis A.
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 mounting portions 22 (FIG. 6) formed integrally with the outer ring 19 so as to project like an arm.

<Regarding rotation-allowable support parts and unit support members>
As shown in FIG. 8, each rotation permitting support component 4 is a rolling bearing. In this example, a tapered roller bearing is applied as the rolling bearing. The rolling bearing has an inner ring 4a fitted to the outer periphery 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 combination 3B. A substantially ring-shaped unit support member assembly 3B is detachably fixed to the end of the unit support member body 3A on the outboard side. Partial concave spherical fitting hole forming portions 3a are formed in the upper and lower portions of the inboard side surface of the unit supporting member combined body 3B.

As shown in FIGS. 7 and 8, a partial concave spherical fitting hole forming portion 3Aa is formed in the upper and lower portions of the outboard side end of the unit supporting member main body 3A. As shown in FIGS. 4 and 5, the unit support member combined body 3B is fixed to the outboard side end of the unit support member main body 3A, and the fitting hole forming portions 3a and 3Aa (FIG. 7) are provided on each of the upper and lower portions. By being combined with each other, a fitting hole continuous with the entire circumference is formed. The outer ring 4b (FIG. 8) is fitted in this fitting hole. Note that, in FIG. 4, the unit support member 3 is represented by a one-dot chain line.

As shown in FIG. 8, each mounting shaft portion 16b of the outer ring 16 is formed with a female screw portion so as to extend in the radial direction, and a bolt 23 that is screwed into the female screw portion is provided. A disc-shaped pressing member 24 is interposed on the end surface of the inner ring 4a, and a pressing force is applied to the end surface of the inner ring 4a by a bolt 23 that is screwed to the female thread portion, so that each rotation-allowable support component 4 is preloaded. I'm giving. This can increase the rigidity of each rotation-allowable support component 4. Even if the weight of the vehicle acts on this hub unit, the initial preload is set so as not to escape. The rolling bearing of the rotation permitting support component 4 is not limited to the tapered roller bearing, and an angular ball bearing may be used depending on the usage conditions such as maximum load. Even in that case, the preload can be applied in the same manner as described above.

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

<About the steering actuator 5>
As shown in FIG. 3, the steering actuator 5 has an actuator body 7 that drives the hub unit body 2 to rotate about the steered axis A (FIG. 2). The actuator 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 rotational output of the speed reducer 27 into the reciprocating linear motion of the linear motion output unit 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 or a gear train, 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 a driven pulley 27b is provided in the linear motion mechanism 25. 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.

A feed screw mechanism such as a slide screw or a ball screw, or a rack and pinion mechanism can be used as the direct acting mechanism 25. In this example, a feed screw mechanism (reverse input preventing mechanism) 25b using a trapezoidal screw is used. Is used. Since the direct acting mechanism 25 includes the feed screw mechanism 25b using 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 adopted instead of the feed screw mechanism 25b using the trapezoidal screw. The actuator body 7 including the motor 26, the speed reducer 27, and the linear motion mechanism 25 is assembled as a subassembly and is detachably attached to the case 6b with bolts or the like. A mechanism for directly transmitting the driving force of the motor 26 to the linear motion mechanism 25 without using a speed reducer is also possible.

The case 6b is formed integrally with the unit support member main body 3A as a part of the unit support member 3. The case 6b is formed in a cylindrical shape with a bottom, and is provided with a motor housing portion that supports the motor 26 and a linear motion mechanism housing portion that supports the linear motion mechanism 25. A fitting hole for supporting the motor 26 at a predetermined position in the case is formed in the motor housing portion. The linear motion mechanism accommodating portion is formed with 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 move forward and backward, and the like.

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 which is a coupling portion of the first steering device 11 (FIG. 3). It has a part 6d. The shock absorber mounting portion 6c and the steering device coupling portion 6d are also integrally formed on the unit support member main body 3A. A shock absorber mounting portion 6c is formed so as to project above the outer surface of the unit support member main body 3A. A steering device coupling portion 6d is formed so as to project on a side surface 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. The vehicle information detection unit 110 includes a vehicle speed detection unit 111, a steering angle detection unit 112, a vehicle height detection unit 113, an actual yaw rate detection unit 114, an actual lateral acceleration detection unit 115, an accelerator pedal sensor 116, and a brake pedal sensor 117.

The vehicle speed detection unit 111 detects the speed (vehicle speed) of the vehicle based on the output of a sensor (not shown) such as a speed sensor installed inside the transmission included in the vehicle, and notifies the ECU 130 of vehicle speed information (simply " Vehicle speed").
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 the steering angle information (simply “ (Also referred to as steering angle).

The vehicle height detection unit 113 measures the distance between the chassis of the vehicle 100 (FIG. 1) and the ground by a laser displacement meter, or an upper arm (not shown) in the suspension device 12 (FIG. 1) of the 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 by an angle sensor or the like. Then, the vehicle height detection unit 113 outputs the detected vehicle height to the 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 outputs actual yaw rate information (also 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 notifies the ECU 130 of the actual lateral acceleration information (simply “actual lateral acceleration”). (Also called) 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.
The brake pedal sensor 117 detects an input to the brake pedal 220 by the driver, and outputs the detected value to the ECU 130 as a brake command value.
The ECU 130 outputs these vehicle information to the control unit 150b of the second steering device 150.

<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 actuator control device 31R for the right wheel and the actuator control device 31L for the left wheel, so that the motor 26 included in the right wheel hub unit 1R and the left wheel hub unit 1L is driven. By driving, the left and right front wheels can be independently steered.

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

As shown in FIG. 10, the main power source Bm and the sub power source Bs supply electric power to the second steering device 150. As the main power source Bm, for example, a battery (for example, a 12V battery) of a vehicle 100 (FIG. 1) equipped with this steering system 101 (FIG. 1) can be applied. The sub power source Bs has a right wheel backup power source Bsa and a left wheel backup power source Bsb. Secondary batteries are generally used as the backup power supplies Bsa and Bsb, but capacitors or capacitors may be applied. Of the above capacitors, use of an electrolytic capacitor, an electric double layer capacitor, or the like is preferable because the capacity per volume is relatively large.

The right wheel actuator control device 31R includes a left wheel abnormality detection unit 221 and the left wheel actuator control device 31L includes a right wheel abnormality detection unit 222. One of the abnormality detecting units 221 (222) of the left and right abnormality detecting units 221 and 222, when detecting the abnormality of the corresponding power system 223R (223L), outputs the abnormality detection information to the left and right abnormality detecting units 221 and 221. It has a mutual monitoring function for giving each other to the other abnormality detection unit 222 (221) in 222.

When an abnormality occurs in the power system 223R supplied from the main power source Bm to the actuator control device 31R for the right wheel, the abnormality is detected by the abnormality detection unit 221 for the left wheel, and the abnormality detection unit 221 for the left wheel outputs the abnormality detection information. This is given to the right wheel abnormality detection unit 222. The left wheel actuator control device 31L to which the abnormality detection information is given supplies power from the right wheel backup power supply Bsa to the right wheel actuator control device 31R instead of the power system 223R having the abnormality.
When an abnormality occurs in the 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 unit 222, and the right wheel abnormality detection unit 222 outputs the abnormality detection information. This is given to the left wheel abnormality detection unit 221. The right wheel actuator control device 31R to which the abnormality detection information is given 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.

The abnormality of each of the power systems 223R and 223L is, for example, disconnection of an electric cable connected from the main power source Bm to the corresponding actuator control device 31R (31L), or an overcurrent flowing through the electric cable. Each of the abnormality detection units 221 and 222 includes, for example, a current sensor or the like, and when a current that is a threshold value or more than a predetermined current is detected with respect to a command value that drives the motor 26, or when no current is detected, the power system 223R and 223L are detected to be abnormal.

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

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

Next, the left and right wheel actuator control devices 31L and 31R cause the left and right front wheels to be symmetrically steered by the left and right wheel hub units 1L and 1R to the toe angle initial state of 0 degrees or toe-in (step S3). The control unit 150b calculates the corrected steering amount of each steering actuator 5 (FIG. 2), that is, the current flowing 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 based on the steering angles detected by the left and right wheel steering angle sensors S _L and S _R (step S6: Yes), the process ends. When steering is not performed to the initial state of the toe angle (step S6: No), the process returns to step S5.

In addition to the above-described processing when an abnormality occurs in the power system, the steering control unit 151 performs control for independently steering the left and right wheels as shown in FIG. The control shown in FIG. 12 and the control shown in FIG. 11 or the like 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, and The left wheel road surface friction coefficient calculation unit 157, the target yaw rate correction unit 158, the target left and right wheel tire angle calculation unit 159, the right wheel command value calculation unit 160, and the left wheel command value calculation unit 161 are provided.

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

The reference lateral acceleration calculation unit 152 calculates the reference lateral acceleration based on the vehicle speed information and the tire angle information acquired from the ECU 130. The reference lateral acceleration calculation unit 152 outputs the calculated reference lateral acceleration as reference lateral acceleration information to the right wheel road surface friction coefficient calculation unit 155 and the left wheel road surface friction coefficient calculation unit 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.
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 based on the actual lateral acceleration information acquired from the ECU 130 and the reference lateral acceleration information input from the reference lateral acceleration calculation unit 152. I do. Specifically, when the reference lateral acceleration information is input from the reference lateral acceleration calculation unit 152, the right wheel road surface friction coefficient calculation unit 155 and the left wheel road surface friction coefficient calculation unit 157 receive the right wheel tire angle calculation unit 153 and the left wheel tire. Tire angle information is acquired from the angle calculation unit 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 store the calculated right wheel road surface friction coefficient information, which is the calculated road surface friction coefficient of the right wheel, and left wheel road surface friction coefficient information, which is the left wheel road surface friction coefficient. , To the target yaw rate correction unit 158.

The target yaw rate calculation unit 156 calculates a target yaw rate based on the vehicle speed information and the steering angle information acquired from the ECU 130 in a predetermined cycle, and outputs the calculated target yaw rate to the target yaw rate correction unit 158 as target yaw rate information.
The target yaw rate correction unit 158 acquires the right wheel road surface friction coefficient information and the left wheel road surface friction coefficient information from the right wheel road surface friction coefficient calculation unit 155 and the left wheel road surface friction coefficient calculation unit 157, and acquires the target yaw rate information from the target yaw rate calculation unit 156. And the target yaw rate is corrected according to the road surface friction coefficient represented by the right wheel road surface friction coefficient information and the left wheel road surface friction coefficient information. The target yaw rate correction unit 158 outputs the corrected target yaw rate as the corrected yaw rate information to the target left and right wheel tire angle calculation unit 159.

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

In equation (1), θ _y is the actual yaw rate of the vehicle represented by the actual yaw rate information, X _A is the accelerator command value, X _B is the brake command value, μ _R is the right wheel road friction coefficient, and μ _L is the left wheel. the road surface friction coefficient, θ _tR1 the target tire angle of the right wheel, θ _tL1 is the target tire angle of the left wheel.
The target left and right wheel tire angle calculation unit 159 outputs the calculated target tire angle of each of the left and right wheels as target tire angle information to the right wheel command value calculation unit 160 and the left wheel command value calculation unit 161.

The right wheel command value calculation unit 160 and the left wheel command value calculation unit 161 respectively acquire the target tire angle information, and from the right wheel tire angle calculation unit 153 and the left wheel tire angle calculation unit 154, the tire representing the current tire angle. The angle information is acquired, and the target tire angle represented by the target tire angle information is compared with the current tire angle. The right wheel command value calculation unit 160 and the left wheel command value calculation unit 161 represent the amounts by which the right wheel hub unit 1R and the left wheel hub unit 1L are respectively steered according to the deviation amount between the target tire angle and the current tire angle. The right wheel steering amount information and the 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 includes 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 actuator control device 31R for the right wheel and the actuator control device 31L for the left wheel are controlled by the right wheel command value calculation unit 160 and the left wheel command value calculation unit 161 to the right wheel steering amount. When the information and the left wheel steering amount information are input, the position information of each motor 26 representing 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 acquired. The target position of the motor 26 is determined based on the above, and the current flowing to each motor 26 is output to correct the steering angles of the right wheel hub unit 1R and the left wheel hub unit 1L. The steering angle information of the right wheel hub unit 1R and the left wheel hub unit 1L is output from the right wheel steering angle sensor S _R and the left wheel steering angle sensor S _L to the steering control unit 151.

As shown in FIG. 4, each of the actuator control devices 31R and 31L outputs a current according to the current command signal input from the steering control unit 151 to drive and control the steering actuator 5. The actuator control devices 31R and 31L control the electric power supplied to the coil of the motor 26. The actuator control devices 31R and 31L form, for example, a half-bridge circuit using a switch element (not shown), and perform PWM control that determines the motor applied voltage based on the ON-OFF duty ratio of the switch element. As a result, the angle of the wheel can be slightly changed in addition to the steering operation by the driver's steering wheel operation. The amount of toe angle can be adjusted according to the vehicle speed and the like even when traveling straight.

<Effect>
According to the steering system 101 described above, by providing the second steering device 150, it is possible to correct the steering regardless of the operation of the steering wheel. That is, in the conventional vehicle, when the vehicle slightly wobbles, the driver needs to perform the correction steering in order to correct the wobble, but in the vehicle including the second steering device 150, the driver turns the steering wheel. It is possible to correct the wobble of the vehicle without performing the operation of. Therefore, the straight running stability of the vehicle is improved.
At the time of cornering, the driver can operate the steering wheel according to the vehicle information, and by correcting the steering amount of each of the left and right wheels so that the vehicle can turn more efficiently, cornering is possible on the ideal line, and the steering wheel of the driver 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 the left and right wheel abnormality detection units 221 and 222 having a mutual monitoring function, the power system 223R (from the main power source Bm to one actuator control device 31R (31L) ( 223L), an abnormality detection unit 221 (222) of one actuator control device 31R (31L) gives abnormality occurrence information to the other abnormality detection unit 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 given, replaces the power system 223R (223L) having the abnormality with one actuator from the auxiliary power source Bs. Electric power is supplied to the control device 31R (31L). After that, the toe angles of the left and right wheels are operated to predetermined reference values, and the motor control is stopped. If the toe angles of the left and right wheels are returned to the predetermined reference value and the reverse input from the road surface is prevented by the feed screw mechanism 25b using a sliding screw such as a trapezoidal screw, the wobbling of the hub unit 1 will be suppressed while the control is stopped. This can be prevented, and the vehicle can be moved to a state where it can be reliably stopped by the driver's steering wheel operation to ensure safety.

<About other embodiments>
In the following description, the parts corresponding to the items previously described in the respective embodiments will be designated by the same reference numerals, and overlapping description will be omitted. When only a part of the structure is described, the other parts of the structure are the same as those described above unless otherwise specified. The same operation and effect are obtained from the same configuration. Not only the combination of the parts specifically described in each of the embodiments, but also the embodiments may be partially combined as long as there is no particular problem in the combination.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS.
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 in 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 a vehicle speed, a steering angle, an actual yaw rate, an actual lateral acceleration, an accelerator command value, and a brake command value from the ECU 130 as vehicle information. The actuator control device 31R for the right wheel and the actuator control device 31L for the left wheel are controlled.
Then, the target left and right wheel tire angle calculation unit 159 of the steering control unit 151 calculates the target angle of each of the left and right tires based on the following equation (2).

In Expression (2), θ _HR indicates the steering angle of the right front wheel, θ _HL indicates the steering angle of the left front wheel, μ _HR indicates the friction coefficient between the right front wheel and the road surface, and μ _HL indicates the friction coefficient between the left front wheel and the road surface. The other terms are the same as those described in the equation (1).
Even when the first steering device 11 and the second steering device 150 steer different wheels from each other, the second steering device 150 determines the steering angle of the first steering device 11 and the vehicle speed. The steering can be performed, and the running stability of the vehicle can be improved.

Also in the second embodiment, as in the first embodiment, when an abnormality occurs in the power system supplied from the main power source Bm (FIG. 10) to the one actuator control device 31R (31L), one actuator One abnormality detection unit 221 (222) in the control device 31R (31L) gives abnormality occurrence information to the other abnormality detection unit 222 (221). The other actuator control device 31L (31R) including the other abnormality detection unit 222 (221) to which the abnormality occurrence information is given is configured such that, instead of the power system having the abnormality, one actuator from the auxiliary power source Bs (FIG. 10) is used. Electric power is supplied to the control device 31R (31L). After that, the toe angles of the left and right wheels are operated to predetermined reference values, and the motor control is stopped. If the toe angles of the left and right wheels are returned to the predetermined reference value and the reverse input from the road surface is prevented by the feed screw mechanism 25b (FIG. 3) that uses a sliding screw such as a trapezoidal screw, the hub unit will be stopped while the control is stopped. Can be prevented, and the vehicle can be moved to a state where it can be reliably stopped by the driver's operation of the steering wheel to ensure safety.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIGS.
The steering system 101 according to the third embodiment is different from the first embodiment in that it includes _{two second} steering devices 150 ₁ and 150 ₂ .
One of the second steering devices 150 ₁ performs the same operation as the second steering device 150 of the first embodiment, and the other second steering device 150 ₂ of the second steering device 150 ₂ of the second embodiment. The same operation as the steering device 150 is performed.

According to this steering system 101, since the plurality of (two in this example) second steering devices 150 ₁ and 150 ₂ are provided, it is possible to more independently steer the four wheels, It is possible to improve the running stability of the vehicle 100.
Further, similar to the first and second embodiments, when an abnormality occurs in the power system supplied from the main power source Bm (FIG. 10) to one actuator control device, one abnormality detection in one actuator control device is detected. The unit provides the abnormality occurrence information to the other abnormality detection unit. The other actuator control device including the other abnormality detection unit to which the abnormality occurrence information is given supplies electric power from the auxiliary power source to the one actuator control device instead of the power system having the abnormality. After that, the toe angles of the left and right wheels are operated to predetermined reference values, and the motor control is stopped. If the toe angles of the left and right wheels are returned to the predetermined reference value and the reverse input from the road surface is prevented by the feed screw mechanism 25b (FIG. 3) that uses a sliding screw such as a trapezoidal screw, the hub unit will be stopped while the control is stopped. Can be prevented, and the vehicle can be moved to a state where it can be reliably stopped by the driver's operation of the steering wheel to ensure safety.

In each of the embodiments, when an abnormality occurs in the power system, the toe angles of the left and right wheels are operated to the predetermined reference values, and the motor control is stopped. However, the control is not limited to this. .. For example, when the abnormality detection information is given from one abnormality detection unit to the other abnormality detection unit, the actuator control device for the left and right wheels supplies power from the auxiliary power supply to the actuator control device including the one abnormality detection unit. The control of the steering actuator may be continued.
In this case, even if an abnormality occurs in one of the power systems, the second steering device can individually steer the left and right wheels and individually and continuously adjust the toe angles of the left and right wheels. Is.

In each of the above-described embodiments, the case where the steering command device 200 is the steering wheel has been described, but a manual steering command device other than the steering wheel, for example, a joystick may be used, or an automatic steering command device as shown in FIG. 9, for example. It may be 200A. The automatic steering command device 200A is a device that recognizes the vehicle surroundings and the like from the vehicle surroundings detecting unit 230 and automatically generates a steering command. The vehicle surroundings detection means 230 is, for example, a sensor such as a camera or a millimeter wave radar.

The automatic steering command device 200A recognizes, for example, a white line and an obstacle on the road, and generates and outputs a steering command. The automatic steering command device 200A may be a part of a device that automatically drives the vehicle or a device that assists steering by manual driving. Even in such a vehicle including the steering command device 200A that automatically generates a steering command, by providing the second steering device 150, an operation that cannot be performed by the first steering device 11, such as toe angle control, can be performed. Further, the main steering in the traveling direction of the vehicle can be performed by the first steering device 11 and the correction can be performed by the second steering device 150, and the direction of the vehicle can be corrected in response to the steering amount command. Therefore, it becomes possible to maintain the traveling stability of the vehicle.

The embodiments for carrying out the present invention have been described above based on the embodiments, but the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1... Hub unit with steering function, 2... Hub unit main body, 3... Unit support member, 5... Steering actuator, 6... Knuckle (suspension frame parts), 9F... Front wheel, 9R... Rear wheel, 11... First Steering device, 12... Suspension device, 15... Hub bearings, 31L, 31R... Left and right wheel actuator control device, 100... Vehicle, 101... Steering system, 110... Vehicle information detection unit, 150... Second steering device, 200... Steering command device 221... Left wheel abnormality detection unit, 222... Right wheel abnormality detection unit, 223R, 223L... Electric 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 the left and right front wheels of the vehicle in accordance with a steering amount command output from the steering command device;
A second steering device that individually steers one or both of the front and rear wheels by driving a steering actuator provided in the vehicle;
A main power supply and a sub power supply for supplying electric power to the second steering device,
A vehicle information detection unit that detects vehicle information indicating the state of the vehicle,
The second steering device includes left and right wheel actuators that individually control the steering actuators of the other left and right wheels based on the vehicle information including the steering angle of one of the left and right wheels. Equipped with a control device,
The left and right wheel actuator control devices each include a left and right wheel abnormality detection unit that detects whether or not there is an abnormality in each power system supplied from the main power source to each actuator control device. One abnormality detection unit in the detection unit has a mutual monitoring function of mutually providing the abnormality detection information when detecting an abnormality of the corresponding power system to the other abnormality detection unit in the left and right wheel abnormality detection units,
When there is no abnormality in any of the power systems by the abnormality detection unit of the left and right wheels, power is supplied from the main power source to the actuator control device of the left and right wheels, respectively.
When abnormality detection information is given from one abnormality detection unit in the abnormality detection unit of the left and right wheels to the other abnormality detection unit in the abnormality detection unit of the left and right wheels, instead of the power system having the abnormality, from the sub power supply, A steering system that supplies electric power to an actuator control device that includes the one abnormality detection unit. The steering system according to claim 1, wherein the first steering device is for steering the left and right front wheels in an interlocking manner, and the second steering device is capable of independently steering the left and right wheels. A steering system. The steering system according to claim 1 or 2, wherein the first and second steering devices steer the front wheels that are the same wheels. The steering system according to any one of claims 1 to 3, wherein the vehicle information includes a vehicle speed, a steering angle, a vehicle height, an actual yaw rate, an actual lateral acceleration, an accelerator command value, and a brake command value. .. The steering system according to claim 1 or 2, wherein the first steering device and the second steering device perform steering of wheels different from each other. The steering system according to claim 5, wherein the vehicle information includes a vehicle speed, a steering angle , an actual yaw rate, an actual lateral acceleration, an accelerator command value, and a brake command value. The steering system according to claim 1 or 2, further comprising two of the second steering devices,
One of the second steering device and the first steering device performs steering of the same wheel,
A steering system in which the other second steering device and the first steering device perform steering of different wheels. The steering system according to any one of claims 1 to 7, wherein the actuator control device for the left and right wheels receives the abnormality detection information from one abnormality detection unit to the other abnormality detection unit. A steering system in which electric power is supplied from a power source to an actuator control device including the one abnormality detection unit to continue control of the steering actuator. The steering system according to any one of claims 1 to 7, wherein the actuator control device for the left and right wheels receives the abnormality detection information from one abnormality detection unit to the other abnormality detection unit. Steering system for controlling the steering actuators so that the toe angle of the steering wheel is returned to a predetermined reference value. 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 sub power source. The steering system according to any one of claims 1 to 10, wherein the second steering device is:
A hub unit main body having a hub bearing for supporting wheels,
A unit support member provided on a suspension frame part of a suspension device for rotatably supporting the hub unit body around a steering axis extending in the vertical direction, and rotating the hub unit body around the steering axis. A steering system that uses a hub unit with a steering function that includes a steering actuator. A vehicle provided with the steering system according to any one of claims 1 to 11.

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