JP2013244891A - Inclination detecting device, light control device, and inclination detecting program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect degrees of inclination in a longitudinal direction of own vehicle with respect to a road face, without using a vehicle height sensor, in an inclination detecting device for detecting the degree of inclination in the longitudinal direction of the own vehicle with respect to the road face.SOLUTION: An absolute pitch angle of expressing a degree of inclination in a longitudinal direction of own vehicle with respect to a face orthogonal to a direction of gravity is obtained in a light control system (S105), and the own vehicle acquires a slope of a road under traveling (S170). a pitch angle to a road face expressing the degree of inclination in the longitudinal direction of the own vehicle with respect to the load face is computed by computing a difference between the absolute pitch angle and the slope of the road (S175). The degree of inclination in the longitudinal direction of the own vehicle with respect to the road face is detected without using a vehicle height sensor, by the such light control system.

Description

  The present invention relates to an inclination detection device, a light control device, and an inclination detection program that detect the magnitude of the inclination of the host vehicle in the front-rear direction relative to a road surface.

  A device using a vehicle height sensor is known as the tilt detection device (see, for example, Patent Document 1).

Japanese Patent No. 3384236

However, the vehicle height sensor is generally disposed in the vicinity of the wheel, and there is a problem that the difficulty of mounting and wiring is high.
Therefore, in view of such a problem, in the inclination detection device that detects the magnitude of the inclination of the host vehicle with respect to the road surface, the magnitude of the inclination of the host vehicle with respect to the road surface without using the vehicle height sensor. It is an object of the present invention to make it possible to detect.

  2. The inclination detecting device according to claim 1, wherein the absolute pitch angle acquisition means is an absolute pitch angle representing a degree of inclination in the front-rear direction of the host vehicle with respect to a plane orthogonal to the direction of gravity. The gradient acquisition means acquires the gradient of the road on which the host vehicle is traveling. Then, the inclination angle calculation means calculates the difference between the absolute pitch angle and the road gradient, thereby calculating the road surface pitch angle representing the magnitude of the inclination of the host vehicle with respect to the road surface.

Here, the absolute pitch angle can be detected by a known tilt sensor. The road gradient can be obtained from a known navigation device or the like.
According to such an inclination detection device, the magnitude of the inclination in the front-rear direction of the host vehicle with respect to the road surface can be detected without using a vehicle height sensor.

  In addition, the inclination detection device according to claim 1 includes, as described in claim 2, a gradient estimation unit that estimates a road gradient by monitoring at least the vehicle speed, and the gradient acquisition unit includes the gradient estimation unit. You may make it acquire the estimation result by a means.

  For example, when the vehicle does not exhibit a driving force or a braking force, it is possible to estimate the road gradient by monitoring the rate at which the vehicle speed changes. Further, when the vehicle exhibits driving force (Claim 3) or when braking force is exhibited (Claim 4), it is monitored how the vehicle speed changes according to the magnitude of these forces. Thus, the slope of the road can be estimated.

  Therefore, according to such an inclination detection device, the road gradient is estimated by monitoring the vehicle speed, and therefore the magnitude of the inclination of the host vehicle in the front-rear direction can be detected without acquiring the road gradient from outside the device. can do.

  Moreover, in order to achieve the said objective, it is good also as a light control apparatus as described in Claim 5, and good also as a tilt detection program as described in Claim 6.

It is explanatory drawing which shows schematic structure of the light control system 1 to which this invention was applied. It is a flowchart which shows the write control process which the control part 10 (CPU11) performs. It is a graph which shows the relationship between the accelerator opening (throttle opening), the change rate of speed, and the gradient of a road. It is a graph which shows the relationship between the change rate of brake hydraulic pressure, speed, and the gradient of a road. It is a side view which shows the model for demonstrating the pitch angle of a vehicle. It is a flowchart which shows the write control process of a modification.

Embodiments according to the present invention will be described below with reference to the drawings.
[Configuration of this embodiment]
The light control system 1 is a system that is mounted on a vehicle such as a passenger car, for example, and controls an irradiation range (direction of the optical axis) by a pair of headlamps 32 mounted on the left and right of the vehicle. Specifically, as shown in FIG. 1, a control unit 10, a vehicle speed sensor 21, a tilt sensor 22, a throttle opening sensor 23, a brake hydraulic pressure sensor 24, and a headlamp driving unit 31 are provided.

  The vehicle speed sensor 21 is configured as a well-known vehicle speed sensor that outputs a vehicle speed signal corresponding to the number of wheel rotations per unit time to the control unit 10. The inclination sensor 22 detects an absolute pitch angle indicating the inclination of the vehicle body in the front-rear direction with respect to a horizontal plane (a reference plane fixed with respect to the vertical direction), and outputs the detected absolute pitch angle to the control unit 10.

  As such an inclination sensor 22, for example, a sensor that detects the position of an object (for example, a ball) that can move according to gravity by an electric method is generally used. Note that the absolute pitch angle is positive when the vehicle nose (front of the vehicle) is lowered, and negative when the vehicle tail (rear of the vehicle) is lowered.

  The throttle opening sensor 23 detects the throttle opening (for example, the ratio of the depression amount of the accelerator pedal with respect to when the accelerator is fully opened), and outputs the throttle opening to the control unit 10. The brake hydraulic pressure sensor detects the brake hydraulic pressure and outputs the brake hydraulic pressure to the control unit 10.

  The headlamp driving unit 31 is provided for each headlamp 32 and is configured as an actuator that drives each headlamp 32. The headlamp drive unit 31 includes a swivel motor for changing the direction of the optical axis of the headlamp 32 in the horizontal direction, and a leveling motor for changing the direction of the optical axis of the headlamp 32 in the vertical direction. ing.

  The control unit 10 is configured as a known microcomputer including a CPU 11 and a memory 12 such as a ROM or a RAM, and executes a program (including an inclination detection program) recorded in the memory 12.

[Process of this embodiment]
The control unit 10 configured as described above executes the write control process shown in FIG. The light control process detects a pitch angle with respect to the road surface indicating the magnitude of the inclination of the host vehicle with respect to the road surface, and the optical axis of the headlamp 32 is set to a predetermined angle with respect to the road surface according to the road surface pitch angle. Is a process for controlling the direction of the.

  The light control process is a process that is started, for example, when the power of the headlamp of the vehicle is turned on, and then repeatedly performed at a constant cycle (for example, every 100 ms). In the light control process, first, the absolute pitch angle detected by the tilt sensor 22 is acquired (S105), and the throttle opening and brake hydraulic pressure detected by the throttle opening sensor 23 and the brake hydraulic pressure sensor 24 are acquired (S110). .

  Then, the vehicle speed detected by the vehicle speed sensor 21 is acquired (S115), and the travel distance after the counter reset is detected (S120). In this process, the distance is calculated by multiplying the vehicle speed by the period of this process.

  Subsequently, it is determined whether or not the amount of fluctuation of the throttle opening and the brake hydraulic pressure (difference from the previous acquired value) is within a certain value (S125). The constant value in the light control process is individually set according to each parameter value (throttle opening, brake oil pressure, absolute pitch angle, vehicle speed fluctuation amount), for example, and 10% to 2 of the previous acquired value. It is set to a value of about 20%.

  If the fluctuation amount of the throttle opening and the brake hydraulic pressure is not within a predetermined value (S125: NO), the counter value is reset (set to 0) (S145). Then, the previously detected road surface pitch angle value (previous value) is held in the memory 12 as the currently detected road surface pitch angle value (S150), and the process proceeds to S180 described later.

  If the fluctuation amount of the throttle opening and the brake hydraulic pressure is within a certain value (S125: YES), it is determined whether or not the variation amount of the absolute pitch angle acquired from the inclination sensor 22 is within the certain value (S130). This process detects that the absolute pitch angle has fluctuated suddenly when the vehicle is traveling on an uneven road. In such a situation, the direction of the optical axis is made constant by making the direction of the optical axis constant. It is a process for suppressing that moves in small steps.

  If the variation amount of the absolute pitch angle is not within a certain value (S130: NO), the process proceeds to the above-described S145. If the absolute pitch angle variation is within a certain value (S130: YES), it is determined whether the vehicle speed variation is within a certain value (S135).

  If the vehicle speed fluctuation amount is not within the predetermined value (S135: NO), the process proceeds to S145 described above. If the vehicle speed fluctuation amount is within a certain value (S135: YES), it is determined whether or not the travel distance after the counter reset is equal to or greater than a reference value (S140).

  Here, the vehicle speed fluctuation amount is detected because the acceleration tends to change again immediately after the acceleration has suddenly changed, and in this case, the direction of the optical axis is prevented from being frequently changed. . Further, the reference value of the travel distance is set to a distance (for example, about 10 m (may be a value that increases as the speed increases)) that the driver does not care about changes in the direction of the optical axis during travel. .

  If the travel distance is less than the reference value (S140: NO), the counter is incremented (S155). Then, similarly to the process of S150, the previously detected road surface pitch angle value (previous value) is held in the memory 12 as the currently detected road surface pitch angle value (S160), and the process proceeds to S180 described later. .

  If the travel distance is equal to or greater than the reference value (S140: YES), the counter value is reset (S165) in the same manner as the process of S145. Then, the slope of the road on which the vehicle travels is calculated (S170).

  In this process, the gradient of the road is estimated by monitoring changes in the vehicle speed with respect to the throttle opening and the brake hydraulic pressure. Specifically, as shown in FIGS. 3 and 4, the control unit 10 specifies the road gradient according to the throttle opening (accelerator opening), the brake hydraulic pressure, and the rate of change (acceleration) of the vehicle speed. Is stored in the memory 12, and the throttle opening, the brake hydraulic pressure, and the vehicle speed are monitored, and the slope of the road on which the host vehicle travels is calculated by referring to this map.

  Subsequently, the road surface pitch angle is calculated, and the calculated road surface pitch angle is recorded in the memory 12 (S175). In this process, the road pitch angle is calculated by calculating the difference between the absolute pitch angle and the road gradient. That is, as shown in FIG. 5, the absolute pitch angle α is obtained from the inclination sensor 22, and the road gradient β is obtained in the process of S170. In the process of S175, the road surface pitch angle θ is obtained by α−β (or β−α).

  Subsequently, based on the latest road surface pitch angle recorded in the memory 12, the angle of the optical axis at which the direction of the optical axis is a predetermined angle with respect to the road surface is calculated, so that the angle of the optical axis is obtained. A command for control is transmitted to the headlamp driving unit 31 (S175). The head lamp drive unit 31 receives this command and controls the direction of the optical axis of the head lamp 32.

When such processing ends, the write control processing ends.
[Effects of this embodiment]
In the light control system 1 described in detail above, the control unit 10 acquires an absolute pitch angle indicating the magnitude of the inclination of the vehicle in the front-rear direction with respect to a plane orthogonal to the direction of gravity, and the vehicle is traveling Get the slope of the road. Then, by calculating the difference between the absolute pitch angle and the road gradient, the road surface pitch angle representing the magnitude of the inclination of the vehicle in the front-rear direction with respect to the road surface is calculated. Furthermore, the direction of the optical axis of the headlight is controlled at a constant angle with respect to the road surface in accordance with the inclination.

Here, the absolute pitch angle can be detected by a known tilt sensor. The road gradient can be obtained from a known navigation device or the like.
According to such a light control system 1, it is possible to detect the magnitude of the inclination of the host vehicle in the front-rear direction with respect to the road surface without using a vehicle height sensor. And the direction of the optical axis of the headlight can be appropriately controlled according to the magnitude of this inclination.

In the light control system 1, the control unit 10 estimates the road gradient by monitoring at least the vehicle speed.
For example, when the vehicle does not exhibit driving force or braking force, the road gradient is estimated by monitoring the rate at which the vehicle speed changes. In addition, when the vehicle exhibits a driving force or a braking force, it monitors how the vehicle speed changes according to these forces.

  According to the light control system 1 as described above, the road gradient is estimated by monitoring parameters including at least the vehicle speed among parameters such as the vehicle speed, the driving force, and the braking force. It is possible to detect the magnitude of the inclination of the vehicle in the front-rear direction without obtaining it.

[Other Embodiments]
Embodiments of the present invention are not limited to the above-described embodiments, and can take various forms as long as they belong to the technical scope of the present invention.

  For example, in the above embodiment, the direction of the optical axis of the headlamp is not changed when the fluctuation of the throttle opening and the brake hydraulic pressure is large (S125: NO). Even if it is large, the direction of the optical axis of the headlamp may be changed. In this case, as shown in FIG. 6, the process of S125 shown in FIG. 2 may be omitted, and the process immediately proceeds to S130.

In this way, it is possible to improve the responsiveness when changing the direction of the optical axis of the headlamp when the throttle opening and the brake hydraulic pressure vary greatly.
In the above embodiment, the road gradient is estimated in consideration of the throttle opening and the brake hydraulic pressure. However, the road gradient may be estimated only from the vehicle speed. This is because when the throttle opening and the brake hydraulic pressure are 0, the rate of change of the vehicle speed varies depending on the gradient, and therefore the gradient can be estimated by monitoring the vehicle speed.

Furthermore, in the above embodiment, the road surface pitch angle is used for the optical axis control of the headlight, but it can be used not only for the optical axis control but also for vehicle control such as vehicle attitude control.
[Correspondence Relationship Between Configuration of Embodiment and Configuration of Present Invention]
The control part 10 in said embodiment is corresponded to the inclination detection apparatus said by this invention. Of the processes executed by the control unit 10, the processes of S105 to S175 correspond to the inclination detection means in the present invention, and the process of S105 corresponds to the absolute pitch angle acquisition means.

  Further, the process of S170 corresponds to the gradient acquisition means and the gradient estimation means referred to in the present invention, and the process of S175 corresponds to the tilt angle calculation means referred to in the present invention. The processing of S180 corresponds to the optical axis direction control means in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Light control system, 10 ... Control part, 11 ... CPU, 12 ... Memory, 21 ... Vehicle speed sensor, 22 ... Inclination sensor, 23 ... Throttle opening sensor, 24 ... Brake hydraulic pressure sensor, 31 ... Headlamp drive part, 32 …head lamp.

Claims (6)

An inclination detection device (10) that is mounted on a vehicle and detects a pitch angle with respect to a road surface that represents a magnitude of an inclination of the vehicle in the front-rear direction with respect to a road surface,
Absolute pitch angle obtaining means (S105) for obtaining an absolute pitch angle representing the magnitude of the inclination of the vehicle in the front-rear direction with respect to a plane orthogonal to the direction of gravity;
Slope acquisition means (S170) for acquiring the slope of the road on which the host vehicle is traveling;
An inclination angle calculating means (S175) for calculating the road pitch angle by calculating a difference between the absolute pitch angle and the road gradient;
An inclination detecting device comprising: The tilt detection apparatus according to claim 1,
Gradient estimation means (S170) for estimating the gradient of the road by monitoring at least the vehicle speed,
The gradient detection device, wherein the gradient acquisition unit acquires an estimation result by the gradient estimation unit. The tilt detection apparatus according to claim 2,
The inclination detecting means estimates the road gradient by monitoring a change in vehicle speed with respect to a throttle opening. In the inclination detection apparatus according to claim 2 or claim 3,
The slope estimation unit estimates the road slope by monitoring a change in vehicle speed with respect to brake hydraulic pressure. A light control device that is mounted on a vehicle and controls the direction of the optical axis of the headlight of the host vehicle,
Inclination detection means (S105 to S175) for detecting the magnitude of the inclination of the vehicle in the front-rear direction with respect to the road surface;
Optical axis direction control means (S180) for controlling the direction of the optical axis of the headlight to a constant angle with respect to the road surface in accordance with the magnitude of the inclination;
With
The light control device according to claim 1, wherein the tilt detection unit is configured as the tilt detection device according to claim 1.   An inclination detection program for causing a computer to function as each means constituting the apparatus according to any one of claims 1 to 5.

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