JP2021070391A - vehicle - Google Patents

Abstract

To obtain a vehicle that includes eight or more wheels and can smoothly turn.SOLUTION: A vehicle 10 includes: a pair of left and right first wheels 22, 28 disposed at each of end portions in a vehicle front-rear direction; second wheels 24, 26 respectively disposed adjacent to and inward in the vehicle front-rear direction of the first wheels 22, 28; a vehicle speed sensor configured to detect vehicle speed; a steering angle sensor configured to detect a steering angle; and a control unit 30 configured to calculate a rotation radius during turning of the vehicle 10 based on detection values of the vehicle speed sensor and the steering angle sensor during turning of the vehicle, and to control steering angles of the first wheels 22, 28 and the second wheels 24, 26 such that when at least one of the vehicle speed and the rotation radius during turning is smaller than a predetermined threshold, actual angles of the first wheels 22, 28 become larger than actual angles of the second wheels 24, 26.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle.

Patent Document 1 discloses an eight-wheeled automobile in which two wheels are arranged at each of the four corners. Further, when the automobile is turned, it is configured so that it can turn on the spot by steering only the outer four wheels while the inner four wheels are floating among the eight wheels.

Japanese Patent No. 06477856

However, in the vehicle described in Patent Document 1, since only four wheels are in contact with the ground when turning, the load on the wheels becomes large. Further, even when the eight wheels are grounded, since only the four wheels are steered, there is a possibility that the turning cannot be performed smoothly due to the frictional force generated between the unsteered wheels and the road surface.

In consideration of the above facts, an object of the present invention is to obtain a vehicle capable of smoothly turning in a configuration provided with eight or more wheels.

The vehicle according to claim 1 is a first wheel provided on each of the left and right ends of the vehicle in the front-rear direction, and a second wheel arranged adjacent to each of the first wheels in the front-rear direction of the vehicle. The vehicle speed sensor that detects the vehicle speed, the steering angle sensor that detects the steering angle, and the turning radius of the vehicle when the vehicle is turning are calculated based on the detection values of the vehicle speed sensor and the steering angle sensor when the vehicle is turning. When at least one of the vehicle speed and the turning radius at the time of turning is smaller than a predetermined threshold value, the first wheel and the first wheel and the said so that the actual steering angle of the first wheel becomes larger than the actual steering angle of the second wheel. It has a control unit that controls the steering angle of the second wheel.

In the vehicle according to claim 1, a pair of left and right first wheels are provided at both ends of the vehicle in the front-rear direction. Further, the second wheel is arranged adjacent to each of the first wheels in the front-rear direction of the vehicle. Therefore, the vehicle is provided with four first wheels and four second wheels. Further, it includes a vehicle speed sensor that detects the vehicle speed, a steering angle sensor that detects the steering angle, and a control unit that controls the steering angles of the first wheel and the second wheel.

Here, the control unit calculates the turning radius when the vehicle is turning based on the vehicle speed detected by the vehicle speed sensor when the vehicle is turning and the steering angle detected by the steering angle sensor. Further, the control unit sets the actual steering angle of the first wheel to be larger than the actual steering angle of the second wheel when at least one of the vehicle speed at the time of turning the vehicle and the turning radius is smaller than a predetermined threshold value. Controls the steering angles of the first and second wheels. As a result, even when the vehicle is turned with the eight wheels in contact with the ground, the frictional force generated between each wheel and the road surface can be reduced.

As described above, according to the vehicle according to the present invention, it is possible to smoothly turn in a configuration including eight or more wheels.

It is a side view of the vehicle which concerns on embodiment. It is a schematic bottom view for demonstrating the angle of a wheel in an embodiment. It is a block diagram which shows the hardware composition of the vehicle which concerns on embodiment. It is a block diagram which shows the functional structure of the vehicle which concerns on embodiment. It is a flowchart which shows the flow of the steering angle control processing in an embodiment. It is the schematic bottom view of the vehicle which shows the 1st modification of the steering angle control processing in Embodiment. It is the schematic bottom view of the vehicle which shows the 2nd modification of the rudder angle control processing in embodiment.

The vehicle 10 according to the embodiment will be described with reference to the drawings. The arrows FR, UP, and RH, which are appropriately described in each figure, indicate the upward direction, the upward direction, and the right direction of the vehicle, respectively. Hereinafter, when the explanation is simply made using the front-rear, up-down, and left-right directions, unless otherwise specified, the front-rear direction of the vehicle front-rear direction, the up-down direction of the vehicle up-down direction, and the left-right direction when facing the vehicle front direction are used. ..

As shown in FIG. 1, the vehicle 10 according to the present embodiment includes a substantially box-shaped vehicle body 12. Further, the vehicle 10 is an electric vehicle having a symmetrical structure in the front-rear direction, and is configured to be able to travel in any direction in the front-rear direction. Therefore, in the following description, one side in the vehicle front-rear direction will be referred to as the vehicle front side for convenience, and the other side in the vehicle front-rear direction will be referred to as the vehicle rear side for convenience.

The vehicle body 12 constituting the vehicle 10 is configured by connecting the first vehicle body unit 14, the second vehicle body unit 16, the third vehicle body unit 18, and the fourth vehicle body unit 20 in order from the front side of the vehicle. The lower portion of the first vehicle body unit 14 has a shape that bulges toward the front side of the vehicle, and the first front wheel 22 as the first wheel and the second front wheel 24 as the second wheel are formed in the bulging portion. And are provided. Further, a first display unit 14A is provided on the side surface of the first vehicle body unit 14, and is configured so that an image can be displayed on the first display unit 14A.

The second vehicle body unit 16 is formed in a substantially rectangular shape when viewed from the side. Further, on the side surface of the second vehicle body unit 16, a second display unit 16A having a substantially rectangular shape in a second side view is provided. The second display unit 16A is configured to be continuous with the first display unit 14A so that an image can be displayed.

The third vehicle body unit 18 has substantially the same outer shape as the second vehicle body unit 16, and a third display unit 18A is provided on the side surface of the third vehicle body unit 18 so as to be continuous with the second display unit 16A. ing. An image can be displayed on the third display unit 18A.

The fourth vehicle body unit 20 has an outer shape that is symmetrical with respect to the first vehicle body unit 14, and has a shape in which the lower portion bulges toward the rear side of the vehicle. A first rear wheel 28 as a first wheel and a second rear wheel 26 as a second wheel are provided on the bulging portion. Further, a fourth display unit 20A is provided on the side surface of the fourth vehicle body unit 20 so as to be continuous with the third display unit 18A, and is configured so that an image can be displayed on the fourth display unit 20A. .. In the present embodiment, as an example, the first display unit 14A, the second display unit 16A, the third display unit 18A, and the fourth display unit 20A are provided on both side surfaces of the vehicle body 12.

As shown in FIG. 2, the vehicle 10 is provided with eight wheels. A pair of left and right first front wheels 22 are provided at the front end of the vehicle 10, and a second front wheel 24 is provided adjacent to each of the first front wheels 22 on the rear side of the vehicle (inside in the front-rear direction of the vehicle). Has been done. That is, the second front wheel 24L is provided on the vehicle rear side of the first front wheel 22L on the left side of the vehicle, and the second front wheel 24R is provided on the vehicle rear side of the first front wheel 22R on the right side of the vehicle.

On the other hand, a pair of left and right first rear wheels 28 are provided at the rear end of the vehicle 10, and are adjacent to each of the first rear wheels 28 on the vehicle front side (inside in the vehicle front-rear direction). Two rear wheels 26 are provided. That is, the second rear wheel 26L is provided on the vehicle front side of the first rear wheel 28L on the left side of the vehicle, and the second rear wheel 26R is provided on the vehicle front side of the first rear wheel 28R on the right side of the vehicle. There is. Here, in the present embodiment, the steering angles of the first front wheel 22, the second front wheel 24, the first rear wheel 28, and the second rear wheel 26 can be controlled independently.

Here, in the present embodiment, the redundant design is enabled by diverting two sets or four sets of the base vehicle system. Specifically, 4 sets of front suspension, 2 sets of front corner brakes, 2 sets of corner brakes with parking function, and 4 sets of steering mechanism are diverted. In addition, 8 sets of wheels and tires are diverted. Further, the vehicle 10 employs a linkless steering by wire.

FIG. 3 is a block diagram showing a hardware configuration of the vehicle 10. As shown in FIG. 3, the vehicle 10 includes an ECU (Electrical Control Unit) 30 as a control unit.

The ECU 30 includes a CPU (Central Processing Unit: processor) 32, a ROM (Read Only Memory) 34, a RAM (Random Access Memory) 36, a storage 38, and an input / output interface 40. Each configuration is communicably connected to each other via a bus 42.

The CPU 32 is a central arithmetic processing unit that executes various programs and controls each unit. That is, the CPU 32 reads the program from the ROM 34 or the storage 38, and executes the program using the RAM 36 as a work area. The CPU 32 controls each of the above configurations and performs various arithmetic processes according to the program recorded in the ROM 34 or the storage 38.

The ROM 34 stores various programs and various data. The RAM 36 temporarily stores a program or data as a work area. The storage 38 is composed of an HDD (Hard Disk Drive) or an SSD (Solid State Drive), and stores various programs including an operating system and various data.

The first front wheel steering mechanism 44, the second front wheel steering mechanism 46, the first rear wheel steering mechanism 48, the second rear wheel steering mechanism 50, the vehicle speed sensor 52, and the steering angle sensor 54 are connected to the input / output interface 40. ing.

The first front wheel steering mechanism 44 is a mechanism for steering the first front wheels 22L and the first front wheels 22R, and steers the first front wheels 22L and the first front wheels 22R by a predetermined angle based on a signal from the ECU 30. .. The second front wheel steering mechanism 46 is a mechanism for steering the second front wheel 24L and the second front wheel 24R, and steers the second front wheel 24L and the second front wheel 24R by a predetermined angle based on the signal from the ECU 30. ..

The first rear wheel steering mechanism 48 is a mechanism for steering the first rear wheel 28L and the first rear wheel 28R, and the first rear wheel 28L and the first rear wheel 28R are steered by a predetermined angle based on a signal from the ECU 30. Steer. The second rear wheel steering mechanism 50 is a mechanism for steering the second rear wheel 26L and the second rear wheel 26R, and the second rear wheel 26L and the second rear wheel 26R are steered by a predetermined angle based on the signal from the ECU 30. Steer.

The vehicle speed sensor 52 is mounted on the vehicle 10 and detects the speed (that is, the vehicle speed) of the vehicle 10. Further, the steering angle sensor 54 is mounted on the vehicle 10 to detect the steering angle. The steering angle referred to here refers to the steering angle of the steering wheel during manual operation. Further, in the case of a vehicle during automatic driving or without a driver's seat, it refers to a steering angle calculated based on the course of the vehicle 10.

The vehicle 10 realizes various functions by using the hardware resources shown in FIG. The functional configuration realized by the vehicle 10 will be described with reference to FIG.

As shown in FIG. 4, the vehicle 10 includes a vehicle speed acquisition unit 60, a steering angle acquisition unit 62, a turning radius calculation unit 64, and a steering angle control unit 66 as functional configurations. Each functional configuration is realized by the CPU 32 of the ECU 30 reading and executing the program stored in the ROM 34 or the storage 38.

The vehicle speed acquisition unit 60 acquires the speed of the vehicle 10 detected by the vehicle speed sensor 52. The steering angle acquisition unit 62 acquires the steering angle detected by the steering angle sensor 54.

The turning radius calculation unit 64 is based on the vehicle speed acquired by the function of the vehicle speed acquisition unit 60 when the vehicle 10 is turning and the steering angle acquired by the function of the steering angle acquisition unit 62, and the turning radius calculation unit 64 is the turning radius when the vehicle 10 is turning. Is calculated. The radius of gyration here refers to the radius of the circle drawn by the center of the tire located on the outside when turning. As shown in FIG. 2, in the present embodiment, when the vehicle 10 turns to the left, the radius of the circle drawn by the center of the first front wheel 22R is calculated as the turning radius.

As shown in FIG. 3, the steering angle control unit 66 controls the steering angles of the first front wheel 22, the second front wheel 24, the first rear wheel 28, and the second rear wheel 26. Specifically, in the steering angle control unit 66, when at least one of the vehicle speed and the turning radius at the time of turning is smaller than a predetermined threshold value, the actual steering angle of the first front wheel 22 is larger than the actual steering angle of the second front wheel 24. The rudder angle is controlled so that the rudder angle is also large, and the rudder angle is controlled so that the actual rudder angle of the first rear wheel 28 is larger than the actual rudder angle of the second rear wheel 26.

(Action)
Next, the operation of this embodiment will be described.

(Example of rudder angle control process)
FIG. 5 is a flowchart showing an example of the flow of the steering angle control process by the vehicle 10. This steering angle control process is executed by the CPU 32 reading a program from the ROM 34 or the storage 38, expanding the program into the RAM 36, and executing the program.

The CPU 32 determines in step S102 whether or not the vehicle 10 is turning. Specifically, the CPU 32 determines that it is turning when the steering angle is larger than a predetermined angle.

When the CPU 32 determines in step S102 that the vehicle 10 is turning, the process proceeds to step S104. Further, when the CPU 32 determines in step S102 that the vehicle 10 is not turning, the CPU 32 ends the steering angle control process.

The CPU 32 acquires the vehicle speed V in step S104. Specifically, the CPU 32 acquires the vehicle speed V detected by the vehicle speed sensor 52 by the function of the vehicle speed acquisition unit 60.

The CPU 32 acquires the steering angle θ in step S106. Specifically, the CPU 32 acquires the steering angle θ detected by the steering angle sensor 54 by the function of the steering angle acquisition unit 62. In the present embodiment, as an example, the steering angle θ is acquired immediately after the vehicle speed V is acquired, but the present invention is not limited to this, and the steering angle θ may be acquired first.

In step S108, the CPU 32 determines whether or not the vehicle speed V is smaller than the threshold value Va and the turning radius R is smaller than the threshold value Ra. Then, when both relationships are satisfied, the CPU 32 shifts to the process of step S110. Further, the CPU 32 ends the steering angle control process when the vehicle speed V is equal to or higher than the threshold value Va or at least one of the cases where the turning radius R is equal to or higher than the threshold value Ra. The turning radius R is calculated based on the vehicle speed V and the steering angle θ.

The CPU 32 controls the steering angle in step S110. Specifically, the steering angle is controlled so that the actual steering angle θ1 of the first front wheel 22 is larger than the actual steering angle θ2 of the second front wheel 24, and the actual steering angle θ3 of the first rear wheel 28 is the second. The rudder angle of each wheel is controlled so as to be larger than the actual rudder angle θ4 of the two rear wheels 26. Then, the CPU 32 ends the steering angle control process.

As described above, in the present embodiment, even when the vehicle 10 is turned with the eight wheels in contact with the ground, the frictional force generated between each wheel and the road surface can be reduced. That is, when the actual steering angles of the first front wheel 22 and the second front wheel 24 are the same, the trajectories of the tires of the first front wheel 22 and the second front wheel 24 are different, so that they occur between each wheel and the road surface. Friction force may increase. On the other hand, by controlling the steering angle as in the present embodiment, the frictional force generated between each wheel and the road surface can be reduced. As a result, the vehicle 10 provided with eight or more wheels can be smoothly turned.

The vehicle 10 of the present embodiment can control the steering angle as in the modified examples shown in FIGS. 6 and 7.

(First modification)
FIG. 6 shows steering angle control when the vehicle 10 is brought closer to the shoulder. As shown in FIG. 6, in this modification, the steering angle control unit 66 sets the steering angles of the first front wheel 22, the second front wheel 24, the first rear wheel 28, and the second rear wheel 26 to the same steering angle. Control.

For example, when it is desired to move the vehicle 10 diagonally to the left front, the first front wheel 22, the second front wheel 24, the first rear wheel 28, and the second rear wheel 26 are turned to the left at the same steering angle. As a result, as shown by the arrow in the figure, the vehicle 10 can be translated diagonally to the left front.

(Second modification)
FIG. 7 shows steering angle control when a part of the wheels of the vehicle 10 fails. As shown in FIG. 7, in this modified example, since the second front wheel 24 is in a state of being unable to move due to a failure, the first front wheel 22, the first rear wheel 28, and the first wheel excluding the second front wheel 24 are the first. Two rear wheels 26 are controlled.

An elevating mechanism for elevating and lowering each wheel may be provided. In this case, by raising the failed second rear wheel 26, it can be lifted from the road surface, and no frictional force is generated between the road surface and the second front wheel 24 at the time of turning. That is, the vehicle 10 can be smoothly turned even when some of the wheels are out of order.

Although the embodiments and modifications have been described above, it goes without saying that they can be implemented in various modes without departing from the gist of the present invention. For example, in the above embodiment, the steering angle of each wheel is controlled when the vehicle speed V is smaller than the threshold value Va and the turning radius R is smaller than the threshold value Ra, but the present invention is not limited to this. That is, only the vehicle speed V is detected, and when the vehicle speed V is smaller than the threshold value Va, the steering angle is controlled so that the actual steering angle θ1 of the first front wheel 22 becomes larger than the actual steering angle θ2 of the second front wheel 24. Moreover, the rudder angle of each wheel may be controlled so that the actual rudder angle θ3 of the first rear wheel 28 is larger than the actual rudder angle θ4 of the second rear wheel 26. Further, when only the turning radius R is detected and the turning radius R is smaller than the threshold value Ra, the steering angle is adjusted so that the actual steering angle θ1 of the first front wheel 22 is larger than the actual steering angle θ2 of the second front wheel 24. The rudder angle of each wheel may be controlled so that the actual rudder angle θ3 of the first rear wheel 28 is larger than the actual rudder angle θ4 of the second rear wheel 26.

Further, in the above embodiment, the present invention is applied to the vehicle 10 provided with eight wheels, but the present invention is not limited thereto. For example, it may be applied to a vehicle having 10 or more wheels.

Further, various processors other than the CPU may execute the process in which the CPU 32 reads and executes the software (program) in the above embodiment. In this case, the processor includes a PLD (Programmable Logic Device) whose circuit configuration can be changed after the manufacture of an FPGA (Field-Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), and the like. An example is a dedicated electric circuit, which is a processor having a circuit configuration designed exclusively for it. Further, the above processing may be executed by one of these various processors, or a combination of two or more processors of the same type or different types (for example, a plurality of FPGAs and a combination of a CPU and an FPGA, etc. ) May be executed. Further, the hardware structure of these various processors is, more specifically, an electric circuit in which circuit elements such as semiconductor elements are combined.

Furthermore, in the above embodiment, the storage 38 is used as the recording unit, but the present invention is not limited to this. For example, a recording medium such as a CD (Compact Disk), a DVD (Digital Versatile Disc), and a USB (Universal Versatile Bus) memory may be used as the recording unit.

10 Vehicle 22 First front wheel (first wheel)
24 Second front wheel (second wheel)
26 Second rear wheel (second wheel)
28 First rear wheel (first wheel)
30 ECU (control unit)
52 Vehicle speed sensor 54 Steering angle sensor

Claims (1)

A pair of left and right first wheels on both ends of the vehicle in the front-rear direction,
A second wheel arranged adjacent to each of the first wheels in the front-rear direction of the vehicle,
A vehicle speed sensor that detects the vehicle speed and
A steering angle sensor that detects the steering angle and
When the turning radius of the vehicle when turning is calculated based on the detection values of the vehicle speed sensor and the steering angle sensor when the vehicle is turning, and when at least one of the vehicle speed when turning and the turning radius is smaller than a predetermined threshold value. A control unit that controls the steering angles of the first wheel and the second wheel so that the actual steering angle of the first wheel is larger than the actual steering angle of the second wheel.
Vehicles with.

Images