Vehicle height control device and vehicle height control method

Abstract

This technology provides the ability to accurately identify stuck situations that can be resolved by raising the vehicle's height. [Solution] The vehicle height control device 14 includes an acquisition unit that acquires information on the vehicle height of the rear wheels or the air pressure of the rear wheels from rear wheel sensors provided on each of the pair of rear wheels, acquires information on the wheel speed of the pair of front wheels and the pair of rear wheels, and acquires the result of detecting accelerator operation by the driver; a determination unit that determines that the vehicle is stuck based on the vehicle height of the rear wheels or the air pressure of the rear wheels, and that the pair of front wheels and the pair of rear wheels include both rotating and stationary wheels, and that accelerator operation by the driver is detected, and a control unit that controls the vehicle height adjustment mechanism provided on the pair of rear wheels according to the determination result of the determination unit.

Description

Technical Field

[0001] The present invention relates to a technique for controlling a vehicle height adjustment mechanism to adjust the vehicle height.

Background Art

[0002] In Patent Document 1, a vehicle height adjustment system is disclosed that includes four vehicle height change actuators disposed between a vehicle body and four driving wheels on the front, rear, left, and right sides, which change the vehicle height between each driving wheel and the vehicle body, and a vehicle height adjustment control device that controls these vehicle height change actuators to adjust the vehicle height. This vehicle height adjustment control device includes a stack determination unit that determines that a stack has occurred when the vehicle height corresponding to any one of the four driving wheels is equal to or higher than a set value, the driver has an intention to drive, and the vehicle is not running.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the bottom of the vehicle body hits the road surface side and any wheel floats, the vehicle enters a stack state, but there is a possibility that it can be recovered by raising the vehicle height so that any wheel touches the ground. In a vehicle provided with a vehicle height adjustment mechanism on the rear wheel side, it is preferable to accurately identify a stack state that can be recovered by raising the vehicle height.

[0005] An object of the present invention is to provide a technique that can accurately identify a stack state that can be recovered by raising the vehicle height.

Means for Solving the Problems

[0006] To solve the above problems, a vehicle height control device according to one aspect of the present invention includes: an acquisition unit that acquires information on the vehicle height on the rear wheels or the air pressure of the rear wheels from rear wheel sensors provided on each of a pair of rear wheels, acquires information on the wheel speed of a pair of front wheels and a pair of rear wheels, and acquires the result of detecting accelerator operation by the driver; a determination unit that determines that the vehicle is stuck based on the vehicle height on the rear wheels or the air pressure of the rear wheels, and that the pair of front wheels and a pair of rear wheels include both rotating and stationary wheels, and that accelerator operation by the driver is detected, and a control unit that controls a vehicle height adjustment mechanism provided on a pair of rear wheels according to the determination result of the determination unit.

[0007] Another aspect of the present invention is a vehicle height control method in which each step is performed by a computer. This method includes the steps of: obtaining the rear wheel height or rear tire pressure from rear wheel sensors provided on each of a pair of rear wheels, obtaining information on the wheel speeds of a pair of front wheels and a pair of rear wheels, and obtaining the result of detecting accelerator operation by the driver; determining that the vehicle is stuck based on the rear wheel height or rear tire pressure, and that the pair of front wheels and a pair of rear wheels include both rotating and stationary wheels, and that accelerator operation by the driver is detected, determining to raise the vehicle height; and controlling a vehicle height adjustment mechanism provided on a pair of rear wheels to raise the vehicle height according to the result of the determination. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a technology that can accurately identify a stuck state that can be recovered by raising the vehicle height. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram shows the configuration of the vehicle height control system in the embodiment. [Figure 2] This diagram shows the functional configuration of the vehicle height control system. [Figure 3] This flowchart shows the vehicle height control method of the embodiment. [Modes for carrying out the invention]

[0010] Figure 1 shows the configuration of the vehicle height control system 1 of the embodiment. The vehicle height control system 1 is installed on the vehicle 2 and is capable of adjusting the vehicle height on the rear wheel side. The vehicle 2 may have an autonomous driving control function that enables it to drive autonomously. The vehicle 2 comprises a right rear wheel 10a, a left rear wheel 10b (referred to as "rear wheel 10" if they are not distinguished), a right front wheel 12a, a left front wheel 12b (referred to as "front wheel 12" if they are not distinguished), and the vehicle height control system 1.

[0011] The vehicle height control system 1 includes a vehicle height control device 14, a vehicle height adjustment mechanism 15, a right vehicle height detection sensor 22a, a left vehicle height detection sensor 22b, a first wheel speed detection sensor 24a, a second wheel speed detection sensor 24b, a third wheel speed detection sensor 24c, a fourth wheel speed detection sensor 24d, and an accelerator operation detection sensor 28.

[0012] The ride height adjustment mechanism 15 is capable of adjusting the ride height of the rear wheels 10. The ride height adjustment mechanism 15 includes a right suspension device 16a, a left suspension device 16b (referred to as "suspension device 16" when not distinguished), a high-pressure source 18, a right valve 20a, and a left valve 20b. The right suspension device 16a is connected to the right rear wheel 10a and the vehicle body. The left suspension device 16b is connected to the left rear wheel 10b and the vehicle body. The suspension device 16 is provided in an air-operated and extendable manner, but is not limited to this configuration and may be hydraulic.

[0013] The high-pressure source 18 takes in air and supplies pressurized air, pressurized by a motor, to the suspension device 16. The right valve 20a is located in the supply path from the high-pressure source 18 to the right suspension device 16a. The left valve 20b is located in the supply path from the high-pressure source 18 to the left suspension device 16b. The right valve 20a and the left valve 20b are leveling valves with adjustable opening degrees.

[0014] When the right valve 20a is opened, pressurized air is supplied from the high-pressure source 18 to the right suspension device 16a, causing the right suspension device 16a to extend and the vehicle height on the right rear wheel 10a side to rise. When the left valve 20b is opened, pressurized air is supplied from the high-pressure source 18 to the left suspension device 16b, causing the left suspension device 16b to extend and the vehicle height on the left rear wheel 10b side to rise. An exhaust valve (not shown) is provided in the supply path between the high-pressure source 18 and the suspension device 16, and when the exhaust valve is opened, the suspension device 16 is depressurized and contracts. The opening and closing of the right valve 20a and the left valve 20b are controlled by the vehicle height control device 14.

[0015] The right ride height detection sensor 22a detects the amount of extension and contraction of the right suspension device 16a and detects the ride height on the right rear wheel 10a side based on that amount. The left ride height detection sensor 22b detects the amount of extension and contraction of the left suspension device 16b and detects the ride height on the left rear wheel 10b side based on that amount. The ride height detection sensors 22 send the detection results to the ride height control device 14. The ride height detection sensors 22 are not limited to detecting the amount of extension and contraction of the suspension device 16, but may also be optical sensors or acoustic wave sensors that detect the distance between the vehicle body and the road surface.

[0016] The first wheel speed detection sensor 24a, the second wheel speed detection sensor 24b, the third wheel speed detection sensor 24c, and the fourth wheel speed detection sensor 24d (referred to as "wheel speed detection sensor 24" when not distinguished) detect the wheel speed, which is the rotational speed of each wheel, and send the detection results to the vehicle height control device 14.

[0017] The accelerator pedal 26 is operated by the driver. The accelerator operation detection sensor 28 detects the driver's accelerator operation and sends the detection result to the vehicle height control device 14. The accelerator operation detection sensor 28 detects, for example, the amount of displacement of the accelerator pedal 26.

[0018] The vehicle height control device 14 controls the vehicle height adjustment mechanism 15 based on the detection results of the vehicle height detection sensor 22, the wheel speed detection sensor 24, and the accelerator operation detection sensor 28, thereby raising or lowering the vehicle height on the rear wheel side 10.

[0019] FIG. 2 is a diagram showing the functional configuration of the vehicle height control system 1. The vehicle height control device 14 includes an acquisition unit 30, a stack determination unit 32, an operation determination unit 34, a determination unit 36, and a control unit 38. The acquisition unit 30 acquires information on the vehicle height on the rear wheel 10 side from a pair of vehicle height detection sensors 22. The information on the vehicle height on the rear wheel 10 side may be the distance from the road surface or the sensor value before calculating the distance from the road surface.

[0020] The acquisition unit 30 acquires information on the wheel speeds of the rear wheel 10 and the front wheel 12 from a plurality of wheel speed detection sensors 24. The information on the wheel speed may be the wheel speed, or may be the rotational speed or the sensor value before calculating the wheel speed. The acquisition unit 30 acquires the detection result of the accelerator operation by the driver from the accelerator operation detection sensor 28.

[0021] The stack determination unit 32 determines whether the vehicle 2 is in a stacked state based on the vehicle height on the rear wheel 10 side, and determines whether the vehicle 2 is in a stacked state based on each wheel speed. The stack determination unit 32 determines whether the vehicle height of a pair of rear wheels 10 is below a predetermined height and whether the difference in the vehicle height of the pair of rear wheels 10 is greater than or equal to a predetermined difference.

[0022] The stack determination unit 32 determines that any wheel of the vehicle 2 is in a stacked state when the vehicle height on the pair of rear wheel 10 sides is below a predetermined height or the difference in the vehicle height on the pair of rear wheel 10 sides is greater than or equal to a predetermined difference. If the vehicle height of the pair of rear wheels 10 is below the predetermined height, it is highly likely that the vehicle heights on both rear wheel 10 sides have dropped excessively and the front wheel 12 side is floating. If the difference in the vehicle height on the pair of rear wheel 10 sides is greater than or equal to the predetermined difference, it is highly likely that the vehicle height on one rear wheel 10 side is floating and the vehicle height on the other rear wheel 10 side is sinking. The predetermined height and the predetermined difference are set in advance by experiments or the like. In this way, the stacked state of the vehicle 2 can be determined only by the sensors on the rear wheel 10 side. In particular, by the determination that the vehicle height on the pair of rear wheel 10 sides is below the predetermined height, the stacked state on the front wheel 12 side can be specified even without the sensors on the front wheel 12 side.

[0023] The stack determination unit 32 determines whether the rotating wheels and the stationary wheels are included in the pair of front wheels 12 and the pair of rear wheels 10 based on the wheel speeds of each wheel. The stack determination unit 32 determines that it is a rotating wheel when the wheel speed is equal to or higher than a predetermined high speed. The stack determination unit 32 determines that it is a stationary wheel when the wheel speed is equal to or lower than a predetermined low speed. The stack determination unit 32 may determine that the rotating wheels and the stationary wheels are included when the difference in wheel speeds between the wheels is equal to or higher than a predetermined speed.

[0024] If both the rotating wheels and the stationary wheels are included, there is a high possibility of a stack state. However, depending only on the wheel speed, it may be stacked with mud or snow and cannot be solved by adjusting the vehicle height. Therefore, by including the vehicle height on the rear wheel 10 side in the determination conditions, it is possible to accurately identify that it is a stack state that can be recovered by raising the vehicle height.

[0025] The operation determination unit 34 determines whether an accelerator operation has been performed by the driver based on the detection result of the accelerator operation detection sensor 28, and determines whether the accelerator operation amount is equal to or more than a predetermined amount. When the accelerator operation amount is equal to or more than a predetermined amount, it is determined that there has been an accelerator operation.

[0026] The determination unit 36 receives the determination results from the stack determination unit 32 and the operation determination unit 34, and determines whether to raise the vehicle height based on those determination results. The determination unit 36 determines to raise the vehicle height when it is determined that it is in a stack state based on the vehicle height on the pair of rear wheels 10 side, the rotating wheels and the stationary wheels are included in the pair of front wheels 12 and the pair of rear wheels 10, and an accelerator operation by the driver is detected. As a result, using the vehicle height detection sensor 22 provided on the rear wheel 10, the existing wheel speed detection sensor 24, and the accelerator operation detection sensor 28, it is possible to accurately identify that it is a stack state that can be recovered by raising the vehicle height.

[0027] The determination unit 36 ​​determines to raise the vehicle height when the height of each of the pair of rear wheels is below a predetermined height or the difference in the height of the pair of rear wheels is greater than or equal to a predetermined difference, the pair of front wheels and the pair of rear wheels include both rotating and stationary wheels, and accelerator operation by the driver is detected.

[0028] The decision unit 36 ​​decides to raise the height of the rear wheel 10 that has a lower ride height than the other rear wheel 10 in the pair. If the ride height of both rear wheels 10 is below a predetermined height, the decision unit 36 ​​decides to raise the ride height of both rear wheels 10. If the difference in ride height is greater than or equal to a predetermined difference, the decision unit 36 ​​decides to raise the ride height of only the rear wheel 10 corresponding to the lower ride height.

[0029] The control unit 38 controls the ride height adjustment mechanisms 15 provided on the pair of rear wheels 10 according to the determination result of the determination unit 36. The control unit 38 pressurizes the high-pressure source 18 to open at least one of the right valve 20a and the left valve 20b, thereby extending the suspension device 16 and raising the ride height.

[0030] The control unit 38 raises the vehicle height of the rear wheel 10 that is lower. When the determination unit 36 ​​determines that the vehicle height should be raised, the control unit 38 raises the vehicle height of the pair of rear wheel 10s if the vehicle height of each of the pair of rear wheel 10s is below a predetermined height, and raises the vehicle height of the rear wheel 10 with the lower vehicle height of the pair if the difference in vehicle height between the pair of rear wheel 10s is greater than or equal to a predetermined difference.

[0031] In a modified example, the vehicle height control device 14 may use the detection result of the air pressure detection sensor instead of the vehicle height detection sensor 22. In other words, the rear wheel sensor that detects the degree of compression on the rear wheel side 10 may be either the vehicle height detection sensor 22 or the air pressure detection sensor. The air pressure detection sensor detects the air pressure of the right rear wheel 10a and the left rear wheel 10b and sends the detection result to the vehicle height control device 14. The acquisition unit 30 acquires the air pressure of each of the rear wheels 10 from the air pressure detection sensor.

[0032] The stuck determination unit 32 determines that the vehicle is stuck if the air pressure of each of the pair of rear wheels 10 is above a predetermined pressure or the difference in air pressure between the pair of rear wheels 10 is above a predetermined difference. The decision unit 36 ​​determines to raise the vehicle height if the air pressure of each of the pair of rear wheels 10 is above a predetermined pressure or the difference in air pressure between the pair of rear wheels 10 is above a predetermined difference, the pair of front wheels 12 and the pair of rear wheels 10 include both rotating wheels and stationary wheels, and accelerator operation by the driver is detected.

[0033] If the air pressure of each of the pair of rear wheels 10 is above a predetermined pressure, both rear wheels 10 are excessively compressed, and there is a high probability that the vehicle 2 is stuck. If the difference in air pressure between the pair of rear wheels 10 is above a predetermined difference, one of the rear wheels 10 is compressed, and there is a high probability that the vehicle 2 is stuck.

[0034] The stack determination unit 32 may determine whether the vehicle is stuck using the detection results of the vehicle height detection sensor 22 and the air pressure detection sensor, respectively. In other words, the decision unit 36 ​​adds whether the air pressure of the rear wheels 10 meets a predetermined condition to the decision to raise the vehicle height. For example, the decision unit 36 ​​may determine that the vehicle is stuck based on the vehicle height of the rear wheels 10, determine that the vehicle is stuck based on the air pressure of the rear wheels 10, and if each wheel includes a rotating wheel and a stationary wheel, and if accelerator operation by the driver is detected, then it may decide to raise the vehicle height.

[0035] In yet another variation, the acquisition unit 30 acquires the air pressure of each wheel from air pressure detection sensors provided on each wheel. The stuck determination unit 32 determines that the vehicle is stuck if the air pressure of at least one of the pair of front wheels 12 is below a predetermined low pressure, and the air pressure of the pair of rear wheels 10 is above a predetermined high pressure. This indicates that the front wheels 12 are extended and the rear wheels 10 are compressed, making it highly likely that the vehicle is stuck. In this way, the stuck state can be determined with high accuracy based on the detection results of the air pressure detection sensors.

[0036] Figure 3 is a flowchart showing the vehicle height control method of the embodiment. The acquisition unit 30 acquires information regarding the vehicle height on the rear wheel 10 side from a pair of vehicle height detection sensors 22 (S10), acquires information regarding the wheel speed of the rear wheel 10 and front wheel 12 from a plurality of wheel speed detection sensors 24 (S12), and acquires the detection result of accelerator operation by the driver from the accelerator operation detection sensor 28 (S14).

[0037] The stack determination unit 32 determines whether the vehicle height of the pair of rear wheels 10 is below a predetermined height, or whether the difference in vehicle height between the pair of rear wheels 10 is greater than or equal to a predetermined difference (S16). If the vehicle height of the pair of rear wheels 10 is not below a predetermined height, and the difference in vehicle height between the pair of rear wheels 10 is not greater than or equal to a predetermined difference (N in S16), the process is terminated without raising the vehicle height.

[0038] If the vehicle height of the pair of rear wheels 10 is below a predetermined height, or if the difference in vehicle height between the pair of rear wheels 10 is greater than a predetermined difference (Y in S16), the stack determination unit 32 determines whether the pair of front wheels 12 and the pair of rear wheels 10 include both rotating wheels and stationary wheels based on the wheel speed of each wheel (S18).

[0039] If the pair of front wheels 12 and the pair of rear wheels 10 do not include a rotating wheel and a stationary wheel (N in S18), the process is terminated without raising the vehicle height. If the pair of front wheels 12 and the pair of rear wheels 10 include a rotating wheel and a stationary wheel (Y in S18), the operation determination unit 34 determines whether accelerator operation by the driver has been detected (S20).

[0040] If no accelerator operation by the driver is detected (N in S20), this process is terminated without raising the vehicle height. If accelerator operation by the driver is detected (Y in S20), the decision unit 36 ​​decides to raise the vehicle height (S22). The control unit 38 executes control to raise the vehicle height on the side of the rear wheels 10, which is lower.

[0041] The present disclosure has been explained above based on the examples described. The present disclosure is not limited to the examples described above, and various modifications such as design changes can be made based on the knowledge of those skilled in the art. [Explanation of Symbols]

[0042] 1 Vehicle height control system, 2 Vehicle, 10a Right rear wheel, 10b Left rear wheel, 12a Right front wheel, 12b Left front wheel, 14 Vehicle height control device, 15 Vehicle height adjustment mechanism, 16a Right suspension device, 16b Left suspension device, 18 High-voltage source, 20a Right valve, 20b Left valve, 22 Vehicle height detection sensor, 24 Wheel speed detection sensor, 26 Accelerator pedal, 28 Accelerator operation detection sensor, 30 Acquisition unit, 32 Stack determination unit, 34 Operation determination unit, 36 Decision unit, 38 Control unit.

Claims

1. An acquisition unit that acquires information regarding the vehicle height of the rear wheels or the air pressure of the rear wheels from rear wheel sensors provided on each of the pair of rear wheels, acquires information regarding the wheel speeds of the pair of front wheels and the pair of rear wheels, and acquires the result of detecting accelerator operation by the driver. A determination unit determines that the vehicle is stuck based on the height of the rear wheels or the air pressure of the rear wheels, and when a pair of the front wheels and a pair of the rear wheels include both rotating and stationary wheels, and when accelerator operation by the driver is detected, the determination unit determines whether to raise the vehicle height. A vehicle height control device comprising: a control unit that controls a pair of vehicle height adjustment mechanisms provided on the rear wheels according to the determination result of the determination unit; and other such components.

2. The rear wheel side sensor is a vehicle height detection sensor. The vehicle height control device according to claim 1, characterized in that the determination unit determines to raise the vehicle height when the height of each of the pair of rear wheels is below a predetermined height or the difference in the height of the pair of rear wheels is greater than or equal to a predetermined difference, the pair of front wheels and the pair of rear wheels include both rotating and stationary wheels, and accelerator operation by the driver is detected.

3. The rear wheel side sensor is an air pressure detection sensor that detects the air pressure of the rear wheel, The vehicle height control device according to claim 1, characterized in that the determination unit determines an increase in vehicle height when the air pressure of each of the pair of rear wheels is equal to or greater than a predetermined pressure, or the difference in air pressure between the pair of rear wheels is equal to or greater than a predetermined difference, the pair of front wheels and the pair of rear wheels include both rotating and stationary wheels, and accelerator operation by the driver is detected.

4. The vehicle height control device according to claim 1 or 2, wherein, when the determination unit determines that the vehicle height should be raised, the control unit raises the vehicle height of the pair of rear wheels if the vehicle height of each of the pair of rear wheels is below a predetermined height, and raises the vehicle height of the rear wheel with the lower vehicle height among the pair of rear wheels if the difference in vehicle height between the pair of rear wheels is greater than or equal to a predetermined difference.

5. A vehicle height control method in which each step is performed by a computer, The steps include obtaining the vehicle height or air pressure of the rear wheels from rear wheel sensors provided on each of the pair of rear wheels, obtaining information regarding the wheel speeds of the pair of front wheels and the pair of rear wheels, and obtaining the result of detecting accelerator operation by the driver, Based on the height of the rear wheels or the air pressure of the rear wheels, it is determined that the vehicle is stuck, and if the pair of front wheels and the pair of rear wheels include both rotating and stationary wheels, and if accelerator operation by the driver is detected, the vehicle height is determined to be raised. A method for controlling vehicle height, characterized by including the step of controlling a vehicle height adjustment mechanism provided on a pair of rear wheels in accordance with the result of the above determination to perform control to raise the vehicle height.

Images