Vehicle lamp controller, vehicle lamp system, and vehicle lamp control method

Abstract

A vehicle lamp controller, a vehicle lamp system, and a vehicle lamp control method are provided. The vehicle lamp system includes an acceleration sensor, a vehicle lamp, and the vehicle controller. The controller includes a receiver configured to receive an acceleration information detected by the acceleration sensor, a control unit configured to derive a vehicle longitudinal direction acceleration and a vehicle vertical direction acceleration from the acceleration information, and to generate a control signal for instructing an adjustment of an optical axis of the vehicle lamp, based on a variation in a ratio between a temporal change amount of the vehicle longitudinal direction acceleration and a temporal change amount of the vehicle vertical direction acceleration during at least one of an acceleration and a deceleration of a vehicle, and a transmitter configured to transmit the control signal to an optical axis adjusting portion of the vehicle lamp.

What is claimed is: 
     
       1. A vehicle lamp controller comprising:
 a receiver configured to receive an acceleration information detected by an acceleration sensor;   a control unit configured to derive a vehicle longitudinal direction acceleration and a vehicle vertical direction acceleration from the acceleration information, and to generate a control signal for instructing an adjustment of an optical axis of a vehicle lamp, based on a variation in a ratio between a temporal change amount of the vehicle longitudinal direction acceleration and a temporal change amount of the vehicle vertical direction acceleration during at least one of an acceleration and a deceleration of a vehicle; and   a transmitter configured to transmit the control signal to an optical axis adjusting portion of the vehicle lamp.   
     
     
       2. The controller according to  claim 1 , wherein the control unit plots points corresponding to values detected by the acceleration sensor, over a time during at least one of the acceleration and the deceleration of the vehicle, on a coordinate system having a first axis representing the vehicle longitudinal direction acceleration and a second axis representing the vehicle vertical direction acceleration, and defines a slope of a straight line or a vector obtained from at least two of the points as the ratio. 
     
     
       3. The controller according to  claim 2 , wherein the control unit defines, as the ratio, the slope of the straight line or the vector obtained from the values detected by the acceleration sensor, the values including values detected by the acceleration sensor while the acceleration of the vehicle is within a given range and values detected by the acceleration sensor while the deceleration of the vehicle is within a given range. 
     
     
       4. The controller according to  claim 2 , wherein the control unit obtains a linear approximation with respect to the points, and defines the slope of the linear approximation as the ratio. 
     
     
       5. The controller according  claim 1 , further comprising a memory,
 wherein the control unit obtains a summed angle including a first angle and a second angle from the acceleration information, the summed angle being an inclination angle of the vehicle with respect to a horizontal plane, the first angle being an inclination angle of a road surface with respect to the horizontal plane, and the second angle being an inclination angle of the vehicle with respect to the road surface, and   wherein a reference value of the first angle and a reference value of the second angle are stored in the memory,   wherein, when the summed angle varies while the vehicle is stopped, the control unit generates the control signal using the second angle, that is obtained from the summed angle and the reference value of the first angle, and stores the second angle in the memory as the reference value of the second angle,   wherein, when the summed angle varies while the vehicle is moving, the control unit does not generate the control signal or generates a control signal for maintaining a position of the optical axis, and when the vehicle stops, the control unit stores the first angle, that is obtained from the summed angle and the reference value of the second angle, in the memory as the reference value of the first angle, and   wherein, when the ratio varies, the control unit corrects the position of the optical axis of the vehicle lamp based on the variation in the ratio.   
     
     
       6. The controller according to  claim 5 , wherein the control unit calculates a difference between the reference value of the second angle and the second angle derived from the ratio, and corrects the reference value of the second angle such that the difference is reduced. 
     
     
       7. The controller according to  claim 6 , wherein, when the difference exceeds a threshold value, the control unit corrects the reference value of the second angle by a correction value that is smaller than the threshold value. 
     
     
       8. The controller according to  claim 1 , wherein the control unit obtains an inclination angle of the vehicle with respect to a road surface from the ratio and a reference value of the ratio, that is obtained during at least one of the acceleration and the deceleration of the vehicle on a horizontal plane, and generates the control signal using the inclination angle of the vehicle with respect to the road surface. 
     
     
       9. The controller according to  claim 1 , wherein the acceleration information comprises a summed angle including a first angle and a second angle from the acceleration information, the summed angle being an inclination angle of the vehicle with respect to a horizontal plane, the first angle being an inclination angle of a road surface with respect to the horizontal plane, and the second angle being an inclination angle of the vehicle with respect to the road surface. 
     
     
       10. The controller according to  claim 1 , wherein the control unit is configured to obtain an inclination angle of the vehicle with respect to a road surface based on the variation in the ratio between the temporal change amount of the vehicle longitudinal direction acceleration and the temporal change amount of the vehicle vertical direction acceleration. 
     
     
       11. A vehicle lamp system comprising:
 a vehicle lamp having an adjustable optical axis;   an acceleration sensor; and   a controller configured to control the vehicle lamp,   wherein the controller comprises:   a receiver configured to receive an acceleration information detected by the acceleration sensor;   a control unit configured to derive a vehicle longitudinal direction acceleration and a vehicle vertical direction acceleration from the acceleration information, and to generate a control signal for instructing an adjustment of the optical axis of the vehicle lamp, based on a variation in a ratio between a temporal change amount of the vehicle longitudinal direction acceleration and a temporal change amount of the vehicle vertical direction acceleration during at least one of an acceleration and a deceleration of a vehicle; and   a transmitter configured to transmit the control signal to an optical axis adjusting portion of the vehicle lamp.   
     
     
       12. The vehicle lamp system according to  claim 11 , wherein the acceleration information comprises a summed angle including a first angle and a second angle from the acceleration information, the summed angle being an inclination angle of the vehicle with respect to a horizontal plane, the first angle being an inclination angle of a road surface with respect to the horizontal plane, and the second angle being an inclination angle of the vehicle with respect to the road surface. 
     
     
       13. The vehicle lamp system according to  claim 11 , wherein the control unit is configured to obtain an inclination angle of the vehicle with respect to a road surface based on the variation in the ratio between the temporal change amount of the vehicle longitudinal direction acceleration and the temporal change amount of the vehicle vertical direction acceleration. 
     
     
       14. A vehicle lamp control method comprising;
 obtaining an acceleration information detected by an acceleration sensor;   deriving a vehicle longitudinal direction acceleration and a vehicle vertical direction acceleration from the acceleration information;   calculating a variation in a ratio between a temporal change amount of the vehicle longitudinal direction acceleration and a temporal change amount of the vehicle vertical direction acceleration during at least one of an acceleration and a deceleration of a vehicle; and   adjusting an optical axis of a vehicle lamp based on the ratio.   
     
     
       15. The vehicle lamp control method according to  claim 14 , wherein the obtaining the acceleration information comprises obtaining a summed angle including a first angle and a second angle from the acceleration information, the summed angle being an inclination angle of the vehicle with respect to a horizontal plane, the first angle being an inclination angle of a road surface with respect to the horizontal plane, and the second angle being an inclination angle of the vehicle with respect to the road surface. 
     
     
       16. The vehicle lamp control method according to  claim 14  further comprising obtaining an inclination angle of the vehicle with respect to a road surface based on the variation in the ratio between the temporal change amount of the vehicle longitudinal direction acceleration and the temporal change amount of the vehicle vertical direction acceleration. 
     
     
       17. A method of controlling a part of the vehicle, comprising:
 determining a temporal change amount of a vehicle longitudinal direction acceleration and a temporal change amount of a vehicle vertical direction acceleration detected by an acceleration sensor during at least one of an acceleration and a deceleration of a vehicle;   calculating information on a vehicle angle based on a ratio between the temporal change amount of the vehicle longitudinal direction acceleration and the temporal change amount of the vehicle vertical direction acceleration; and   adjusting the part of the vehicle based on the information on the vehicle angle.    
     
     
       18. The method according to claim 17, wherein the part of the vehicle is a vehicle lamp, and an optical axis of the vehicle lamp is adjusted based on the information on the vehicle angle.