Control device, program, and vehicle lamp

Abstract

Provided is a control device (60) for an actuator (50) that is capable of changing the orientation of a lamp unit (30) by transmitting the torque of a motor (52) to the lamp unit (30) such that the emission direction of light is inclined along a plane (VP). The control device (60) performs first control in which, when the absolute value of the difference between the angle of the emission direction and a target angle (TA) is less than a threshold value (TH), the actuator (50) is controlled such that the angle of the emission direction is made to be a first specific angle (SA1) at which the absolute value of the difference between the angle of the emission direction and the target angle (TA) is not less than the threshold value (TH), and, thereafter, the angle of the emission direction is made to approach the target angle (TA).

Description

Control device, program, and vehicle lighting fixture

[0001] The present invention relates to a control device, a program, and a vehicle lighting device.

[0002] 2. Description of the Related Art Vehicle lamps are known in which the orientation of a lamp unit can be changed by an actuator, and Patent Document 1 listed below discloses such a vehicle headlamp.

[0003] The vehicle headlamp disclosed in Patent Document 1 below includes a lamp unit, an actuator, and a control device that controls the actuator. The actuator is capable of changing the orientation of the lamp unit by using the torque of a motor to tilt the light emission direction of the lamp unit vertically. The control device controls the actuator based on the detection value of an inclination detection device that can detect the inclination angle of the vehicle. Therefore, with this vehicle headlamp, the vertical tilt of the light emission direction of the lamp unit can be changed in accordance with the inclination of the vehicle.

[0004] Patent No. 5947947

[0005] For example, in a vehicle headlamp, the light emission direction relative to the vehicle is generally adjusted during calibration, such as when the headlamp is installed on the vehicle. Such adjustment of the light emission direction is performed, for example, by controlling an actuator based on measurement results from a measurement device that measures the emission direction of light emitted from a lamp unit. Generally, an actuator that can change the orientation of a lamp unit using the torque of a motor may have difficulty finely changing the orientation of the lamp unit. Therefore, when the deviation between the vertical angle of the emission direction and the target angle is small, it may be difficult to further reduce the deviation. Therefore, there is a demand for improving the accuracy of adjustment of the emission direction of light emitted from a lamp unit.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device, a program, and a vehicle lamp that can improve the accuracy of adjusting the emission direction of light emitted from a lamp unit.

[0007] In order to achieve the above-mentioned object, the present invention provides a control device for an actuator that can transmit the torque of a motor to a lighting unit and change the orientation of the lighting unit so that the light emission direction is tilted along a predetermined plane, and is characterized in that, when the absolute value of the difference between the angle of the emission direction and a target angle is less than a threshold value, a first control is performed in which the angle of the emission direction is set to a first specific angle whose absolute value of the difference from the target angle is greater than or equal to the threshold value, and then the actuator is controlled to approach the target angle.

[0008] The present invention also provides a program executed by a control device of an actuator that can transmit the torque of a motor to a lighting unit and change the orientation of the lighting unit so that the light emission direction is tilted along a predetermined plane, and is characterized in that the control device executes a step of performing a first control in which, when the absolute value of the difference between the angle of the emission direction and a target angle is less than a threshold value, the angle of the emission direction is set to a first specific angle whose absolute value of the difference from the target angle is equal to or greater than the threshold value, and then the actuator is controlled to approach the target angle.

[0009] The vehicle lamp of the present invention also comprises a lamp unit, an actuator capable of transmitting motor torque to the lamp unit to change the orientation of the lamp unit so that the light emission direction is tilted along a predetermined plane, and a control device that controls the actuator, wherein when the absolute value of the difference between the emission direction angle and a target angle is less than a threshold value, the control device performs a first control in which the angle of the emission direction is set to a first specific angle whose absolute value of the difference from the target angle is equal to or greater than the threshold value, and then controls the actuator to approach the target angle.

[0010] In the above-described control device, program, and vehicular lamp, when the absolute value of the difference between the emission direction angle of light and the target angle is less than a threshold value, the emission direction angle is set to a first specific angle where the absolute value of the difference from the target angle is equal to or greater than the threshold value, and then approaches the target angle. In other words, the emission direction angle is moved away from the target angle and then approaches the target angle. Therefore, according to the above-described control device, program, and vehicular lamp, even when the absolute value of the difference between the emission direction angle and the target angle is small and it is difficult to directly approach the emission direction angle to the target angle, the emission direction angle can be brought closer to the target angle, and the accuracy of adjustment of the emission direction of light emitted from the lamp unit can be improved.

[0011] The control device may perform second control to change the angle of the emission direction from the target angle toward the first specific angle, when an absolute value of a difference between the angle of the emission direction and the target angle is equal to or greater than the threshold, to set the angle of the emission direction to a second specific angle at which an absolute value of a difference between the angle of the emission direction and the target angle on the first specific angle side of the target angle is equal to or greater than the threshold, and then control the actuator to approach the target angle. Furthermore, the program may cause the control device to perform second control to change the angle of the emission direction from the target angle toward the first specific angle, when an absolute value of a difference between the angle of the emission direction and the target angle is equal to or greater than the threshold, to set the angle of the emission direction to a second specific angle at which an absolute value of a difference between the angle of the emission direction and the target angle on the first specific angle side of the target angle is equal to or greater than the threshold, and then control the actuator to approach the target angle.

[0012] In this case, the control device may perform the first control when an absolute value of a difference between the angle of the emission direction after the second control and the target angle is less than the threshold value. Furthermore, the program may cause the control device to execute the step of performing the first control when an absolute value of a difference between the angle of the emission direction after the step of performing the second control and the target angle is less than the threshold value.

[0013] Generally, rattles tend to occur in the components that make up a motor. Furthermore, rattles tend to occur between torque transmission components, such as gears, that transmit motor torque in an actuator. Therefore, due to the influence of such rattles, the angle of the light emission direction may deviate from the target angle even when the actuator is controlled based on the measured light emission direction. With the above configuration, the emission direction angle changes from the target angle toward the first specific angle to the second specific angle, then approaches the target angle, and then further changes from the target angle toward the first specific angle to the first specific angle, then approaches the target angle. In other words, in both the first and second angle adjustments, the emission direction angle changes from the target angle toward the first specific angle, then the direction of change is reversed, and it approaches the target angle. Therefore, the influence of the rattles described above can be made approximately the same in the first and second adjustments. Furthermore, the difference between the emission direction angle and the target angle immediately after the emission direction angle is brought closer to the target angle for the first time can be considered to be a deviation caused by the influence of backlash when bringing the emission direction angle closer to the target angle as described above. Therefore, when bringing the emission direction angle closer to the target angle for the second time, the actuator can be controlled taking into account the deviation caused by the influence of backlash as described above, thereby further improving the accuracy of the emission direction adjustment.

[0014] In this case, it is preferable that the absolute value of the difference between the second specific angle and the target angle is greater than the absolute value of the difference between the first specific angle and the target angle.

[0015] The effect of the aforementioned backlash cannot be extracted solely from the emission direction angle before the emission direction angle is first brought closer to the target angle. Therefore, to ensure that the emission direction angle changes from the target angle toward the first specific angle, becomes the second specific angle, and then approaches the target angle, it is preferable that the absolute value of the difference between the second specific angle and the target angle is large. However, if the absolute value of this difference is large, the period during which the actuator is controlled tends to be long. As described above, the difference between the emission direction angle and the target angle immediately after the emission direction angle is first brought closer to the target angle can be considered to be a deviation caused by the aforementioned backlash. Therefore, even if the absolute value of the difference between the first specific angle and the target angle is small, the emission direction angle can be brought closer to the target angle after changing from the first specific angle toward the target angle and becoming the first specific angle, thereby shortening the period during which the actuator is controlled. Therefore, with the above configuration, it is easier to shorten the period required to adjust the emission direction while suppressing malfunctions in the control of the actuator, compared to when the absolute value of the difference between the second specific angle and the target angle is smaller than the absolute value of the difference between the first specific angle and the target angle.

[0016] The control device may receive a signal relating to the angle of the emission direction from a measuring device that receives light emitted from the lighting unit and measures the emission direction.

[0017] In the above-described vehicle lamp, the predetermined plane may be substantially parallel to a vertical plane.

[0018] In this case, the weight of the lamp unit may generate torque in the lamp unit such that the angle of the emission direction changes from the target angle toward the first specific angle.

[0019] With this configuration, the direction of the torque transmitted from the motor to the lamp unit when the angle of the emission direction approaches the target angle from the first specific angle side is opposite to the direction of the torque due to the lamp unit's own weight. Therefore, with the above configuration, deviation of the emission direction angle from the target angle due to the influence of rattle can be suppressed compared to when the lamp unit's own weight generates torque that changes the emission direction angle from the target angle toward the opposite side from the first specific angle side. Therefore, with the above configuration, the accuracy of adjustment of the light emission direction can be further improved.

[0020] As described above, the present invention can provide a control device, a program, and a vehicle lamp that can improve the accuracy of adjusting the emission direction of light emitted from a lamp unit.

[0021] Fig. 1 is a schematic diagram showing an adjustment system for adjusting the emission direction of light emitted from a vehicle lamp according to an embodiment of the present invention. Fig. 2 is a diagram showing a schematic diagram of a vehicle headlamp according to an embodiment. Fig. 3 is a diagram showing a low beam light distribution pattern according to the embodiment. Fig. 4 is a flowchart showing an example of the operation of a control device in calibration of a vehicle headlamp. Fig. 5 is a diagram for explaining a target angle and a target range according to the embodiment. Fig. 6 is a diagram showing an example of a change over time in the angle of the emission direction of light during calibration.

[0022] Preferred embodiments of a control device, a program, and a vehicle lamp according to the present invention will be described in detail below with reference to the drawings. The embodiments exemplified below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, the present invention can be modified and improved from the embodiments exemplified below within the scope of the claims. Note that in the drawings referred to below, the dimensions of each component may be changed to facilitate understanding. Also, in the drawings, for ease of viewing, similar components may be assigned reference symbols only in some cases, and some reference symbols may be omitted.

[0023] FIG. 1 is a schematic diagram showing an adjustment system for adjusting the emission direction of light emitted from a vehicle lamp according to an embodiment of the present invention. As shown in FIG. 1 , the adjustment system SY of this embodiment includes a vehicle 100 equipped with a vehicle headlamp 1 as a vehicle lamp, and a measurement device 110 for measuring the emission direction of light emitted from the vehicle headlamp 1. In FIG. 1 , the X-axis direction indicates the front of the vehicle 100, the Z-axis direction indicates the upward direction, and the Y-axis direction, which is perpendicular to the paper and points toward the rear, indicates the rightward direction of the vehicle 100. In this embodiment, the vehicle 100 is disposed on a substantially horizontal floor FL, and the measurement device 110 is disposed on the floor FL in front of the vehicle 100 so as to directly face the vehicle headlamp 1 at a predetermined distance. The term "substantially horizontal" includes, for example, a horizontal state as well as a state inclined relative to the horizontal to such an extent that the influence of the measurement device 110 on the calibration of the vehicle headlamp 1, which will be described later, can be ignored. The state inclined relative to the horizontal includes, for example, a state inclined at a predetermined angle relative to the horizontal, which will be described later.

[0024] First, a description will be given of the vehicle headlamp 1. The vehicle headlamp 1 according to this embodiment mainly comprises a lamp unit 10, a control device 60, a memory 70, a first power supply circuit 81, and a second power supply circuit 82.

[0025] 2 is a diagram schematically illustrating the vehicle headlamp 1 according to this embodiment. As shown in FIG. 2, the lamp section 10 according to this embodiment mainly includes a housing 20, a lamp unit 30, a support member 40, and an actuator 50.

[0026] The housing 20 has a lamp housing 21 and a front cover 22. The front of the lamp housing 21 is open, and the front cover 22 is fixed to the lamp housing 21 so as to close the opening. The space formed by the lamp housing 21 and the front cover 22 is an accommodation space, and the lamp unit 30, the support member 40, and the actuator 50 are accommodated in this accommodation space. The front cover 22 transmits light emitted from the lamp unit 30.

[0027] The lamp unit 30 of this embodiment mainly comprises a main body 31 equipped with a light source (not shown), an upper connection part 32, and a lower connection part 35. Note that the internal structure of the main body 31 is not shown in Fig. 2 .

[0028] In this embodiment, the main body 31 emits light emitted from the light source forward so as to form a low beam light distribution. The low beam emitted from the main body 31 is irradiated forward of the vehicle 100 through the front cover 22. The main body 31 may include a reflector, a projection lens, or the like so that the light from the light source forms a low beam light distribution. An example of the light source is an LED (Light Emitting Diode). The light emitted by the main body 31 is not limited and may be, for example, a high beam, and the main body 31 may be capable of changing the light distribution pattern of the emitted light.

[0029] The upper connection portion 32 of this embodiment includes a base portion 33 extending upward from the main body portion 31 and a connection portion 34 fixed to the rear side of the base portion 33, and the connection portion 34 is connected to the support member 40. The support member 40 of this embodiment is a rod-shaped member extending in the front-to-rear direction and has a generally spherical pivot portion 41 at its front end. The rear end of the support member 40 is fixed to the lamp housing 21. The connection portion 34 has a recess into which the pivot portion 41 fits, and the upper connection portion 32 is connected to the support member 40 by fitting the pivot portion 41 into the recess. The lamp unit 30, with the upper connection portion 32 connected to the support member 40 in this manner, can swing up and down and left and right within a predetermined range relative to the support member 40, with the pivot portion 41 as a fulcrum.

[0030] The lower connecting portion 35 of this embodiment includes a base portion 36 extending downward from the main body portion 31 and a connecting portion 37 fixed to the rear side of the base portion 36, and is connected to a shaft 53 of an actuator 50 (described later). The lamp unit 30 is supported by the support member 40 and the shaft 53.

[0031] The actuator 50 of this embodiment mainly comprises a case 51, a motor 52, and a shaft 53.

[0032] In this embodiment, the case 51 is a box-shaped member having an internal storage space, and is fixed to the lamp housing 21. The motor 52 is a DC motor, and is housed in the storage space of the case 51. The type of the motor 52 is not limited.

[0033] In this embodiment, the shaft 53 is a rod-shaped member extending in the front-rear direction. The shaft 53 has a generally spherical pivot portion 54 at its front end, and a rack 55 behind the pivot portion 54. A hole through which the shaft 53 is inserted is formed in the front portion of the case 51, and the portion of the shaft 53 including the pivot portion 54 is located forward of the case 51, while the portion of the shaft 53 including the rack 55 is located within the accommodation space of the case 51. The shaft 53 is supported by a support mechanism (not shown) so as to be movable along the front-rear direction, which is the direction in which the shaft 53 extends.

[0034] The connection portion 37 of the lower connection portion 35 described above has a recess into which the pivot portion 54 fits, and the pivot portion 54 fits into this recess, thereby connecting the lower connection portion 35 to the shaft 53. The lighting unit 30, with the lower connection portion 35 connected to the shaft 53 in this way, can swing up and down and left and right within a predetermined range relative to the shaft 53, with the pivot portion 54 as a fulcrum.

[0035] The rack 55 is a gear provided on the outer circumferential surface of the shaft 53 along the longitudinal direction of the shaft 53, and meshes with a pinion gear 56 fixed to the output shaft 52a of the motor 52. When the pinion gear 56 rotates due to the torque of the motor 52, the shaft 53 moves in the front-to-rear direction, and when the rotation direction of the motor 52 is reversed, the movement direction of the shaft 53 is reversed.

[0036] Although not illustrated, as the shaft 53 moves forward, the torque of the motor 52 is transmitted to the lamp unit 30, and the lamp unit 30 tilts so as to face upward, with the pivot portion 41 of the support member 40 as a fulcrum. The light emission direction of the main body 31 of the lamp unit 30 is then changed to be upward from before the movement. As the shaft 53 moves rearward, the torque of the motor 52 is transmitted to the lamp unit 30, and the lamp unit 30 tilts so as to face downward, with the pivot portion 41 as a fulcrum, and the light emission direction of the main body 31 is then changed to be downward from before the movement.

[0037] That is, the pinion gear 56 and the shaft 53 are torque transmission members that transmit the torque of the motor 52 to the lamp unit 30, and the actuator 50 transmits the torque of the motor 52 to the lamp unit 30 and can change the orientation of the lamp unit 30 so that the light emission direction is tilted along a plane that is approximately parallel to a vertical plane extending in the front-to-rear direction. Note that "approximately parallel to the vertical plane" includes, for example, a state that is parallel to the vertical plane, as well as a state that is tilted with respect to the vertical plane to an extent that the influence on the calibration of the vehicle headlamp 1, which will be described later, can be ignored, and this state that is tilted with respect to the vertical plane includes, for example, a state that is tilted with respect to the vertical plane by a predetermined angle, which will be described later.

[0038] In addition, the center of gravity 30G of the lighting unit 30 in this embodiment is located forward of the pivot portion 41 and the pivot portion 54, and the weight of the lighting unit 30 generates a torque in the lighting unit 30 that changes the direction of light emission downward.

[0039] The control device 60 is formed of, for example, an integrated circuit such as a microcontroller, an integrated circuit (IC), a large-scale integrated circuit (LSI), or an application specific integrated circuit (ASIC), or an NC (numerical control) device. The control device 60 may or may not use a machine learning device. The control device 60 is electrically connected to a memory 70, a first power supply circuit 81, a second power supply circuit 82, and a transceiver unit 120 provided in the vehicle 100, which will be described later.

[0040] The memory 70 is configured to store information and to be able to read the stored information. The memory 70 is, for example, a non-transitory recording medium, and is preferably a semiconductor recording medium such as a random access memory (RAM) or a read-only memory (ROM), but may also include any type of recording medium, such as an optical recording medium or a magnetic recording medium. Note that the term "non-transitory" recording medium includes all computer-readable recording media except for transient, propagating signals, and does not exclude volatile recording media. Note that the memory 70 and the control device 60 may be provided in an integrated package. The memory 70 stores programs for controlling the lamp unit 30 and the actuator 50 and information necessary for such control. The control device 60 reads the programs and information stored in the memory 70. The memory 70 also stores information in response to instructions from the control device 60.

[0041] The control device 60 of this embodiment reads out a program for controlling the lighting unit 30 from the memory 70, and controls the lighting unit 30 by outputting a signal to the first power supply circuit 81 and controlling the first power supply circuit 81.

[0042] The first power supply circuit 81 includes a driver, and when a control signal is input from the control device 60, the driver adjusts the power supplied from a power supply (not shown) to the light source in the main body 31 of the lamp unit 30. When power is supplied to the light source, light is emitted from the light source, and a low beam is emitted from the lamp unit 30.

[0043] In addition, the control device 60 of this embodiment reads out a program for controlling the actuator 50 from the memory 70 , and controls the actuator 50 by outputting a signal to the second power supply circuit 82 and controlling the second power supply circuit 82 .

[0044] The second power supply circuit 82 includes a driver, and when a control signal is input from the control device 60, the driver adjusts the voltage applied to the motor 52 of the actuator 50 from a power supply (not shown), and the output shaft 52a of the motor 52 rotates in accordance with the applied voltage. The shaft 53 then moves forward and backward, and the torque of the motor 52 is transmitted to the lamp unit 30, changing the orientation of the lamp unit 30 so that the light emission direction is tilted up or down.

[0045] Furthermore, the control device 60 of this embodiment outputs a control signal to the transceiver unit 120 provided in the vehicle 100 to instruct the measuring device 110 to perform measurement.

[0046] In the present embodiment, the control device 60, the memory 70, the first power supply circuit 81, and the second power supply circuit 82 are disposed outside the housing 20. However, at least one of these may be housed in the housing 20, and the second power supply circuit 82 may be housed in the housing space of the case 51 of the actuator 50. The control device 60 may include at least one of the first power supply circuit 81 and the second power supply circuit 82, and may be included in a vehicle control device that controls the engine of the vehicle 100, etc. The first power supply circuit 81 and the second power supply circuit 82 may be provided in an integrated package. The control device 60, the first power supply circuit 81, and the second power supply circuit 82 may be provided in an integrated package. At least one of the first power supply circuit 81 and the second power supply circuit 82 and the memory 70 may be provided in an integrated package, and the control device 60, the memory 70, the first power supply circuit 81, and the second power supply circuit 82 may be provided in an integrated package.

[0047] The transceiver 120 provided in the vehicle 100 is configured to transmit signals to and receive signals from the outside. An example of the transceiver 120 is an antenna. In this embodiment, the transceiver 120 transmits signals input from the control device 60 to an external device as electromagnetic waves, and receives signals transmitted from an external device as electromagnetic waves and outputs the signals to the control device 60.

[0048] 1 , the measuring device 110 will be described. The measuring device 110 according to this embodiment mainly includes a control device 111, a memory 112, a light receiving unit 113, a calculation unit 114, and a transmission / reception unit 115.

[0049] The control device 111 has a configuration similar to that of the control device 60, for example, and controls several components of the measurement device 110. The control device 111 is electrically connected to a memory 112, a light receiving unit 113, a calculation unit 114, and a transmission / reception unit 115.

[0050] The memory 112 has a configuration similar to that of the memory 70, for example. The memory 112 stores programs for controlling several components of the measuring device 110 and information necessary for the control. The control device 111 reads out the programs and information stored in the memory 112. The memory 112 also stores information in response to instructions from the control device 111.

[0051] The light receiving unit 113 of this embodiment has a light receiving surface 113s that receives light, and generates image information indicating an image of the light irradiated onto the light receiving surface 113s. The generated image information is output to the calculation unit 114 via the control device 111. The light receiving unit 113 may be configured, for example, with semiconductor light receiving elements arranged in a matrix. The measurement device 110 is placed on the floor FL so that the light receiving surface 113s faces the vehicle headlamp 1 at a predetermined distance. When a low beam is emitted from the vehicle headlamp 1, the low beam is irradiated onto the light receiving surface 113s, and image information indicating the low beam light distribution pattern, which is an image of the low beam, is output to the calculation unit 114 via the control device 111.

[0052] 3 is a diagram showing a low beam light distribution pattern according to this embodiment, specifically, a diagram showing a low beam light distribution pattern formed on the light receiving surface 113s when the low beam is irradiated onto the light receiving surface 113s. The low beam light distribution pattern PL according to this embodiment is for use in countries and regions where vehicles drive on the left side of the road. The cutoff line CL, which is the upper edge of the low beam light distribution pattern PL, includes a first line CL1, a second line CL2, and a third line CL3. The first line CL1 extends generally horizontally, the second line CL2 extends leftward and upward from the left end of the first line CL1, and the third line CL3 extends generally horizontally from the left end of the second line CL2 to the left. The junction of the first line CL1 and the second line CL2 is an elbow point EP, and a hot zone (not shown), which is the area where the light intensity is highest, is located near the elbow point EP.

[0053] The calculation unit 114 in this embodiment has a configuration similar to that of the control device 60, for example. The calculation unit 114 calculates the emission direction of the low beam with respect to the vehicle 100 based on information about the input image and information previously stored in the memory 112. Examples of the information stored in the memory 112 include the distance between the vehicle 100 and the measurement device 110 and the height from the floor FL to the vehicle headlamp 1. In this embodiment, the calculation unit 114 extracts a position representing the elbow point EP in the image and calculates the angle of the emission direction of the low beam in the vertical direction from the extracted position. Information about the calculated angle is output to the transmission / reception unit 115 via the control device 111. In this embodiment, the angle of the emission direction is defined as zero degrees in a direction parallel to the horizontal direction, a positive angle in an angle formed between a direction above the horizontal direction and the horizontal direction, and a negative angle in an angle formed between a direction below the horizontal direction and the horizontal direction. In this embodiment, the emission direction of the low beam is a direction from the lamp unit 30 toward the elbow point EP. The emission direction angle is the tilt angle of the emission direction with respect to a reference direction, which in this embodiment is the tilt angle of the emission direction with respect to the horizontal. When the orientation of the lamp unit 30 is changed by the actuator 50, the emission direction is tilted along a plane VP that is approximately parallel to a vertical plane extending in the fore-and-aft direction and passes through the elbow point EP.

[0054] The low beam emission direction may be a direction from the lamp unit 30 toward a predetermined position in the low beam light distribution pattern PL, such as a direction from the lamp unit 30 toward a hot zone in the low beam light distribution pattern. The calculation unit 114 only needs to detect the emission direction of light emitted from the lamp unit 30. The light emission direction is a direction toward a predetermined position in the light distribution pattern, and the predetermined position is not limited. The method for detecting such an emission direction is not limited. For example, the calculation unit 114 may extract a position representing a hot zone in the low beam light distribution pattern in the image and calculate the angle of the low beam emission direction in the vertical direction from that position. Furthermore, if the light emitted from the lamp unit 30 is a high beam, for example, the calculation unit 114 may extract a position representing a hot zone in the high beam light distribution pattern and calculate the angle of the high beam emission direction in the vertical direction from that position. Furthermore, the control device 111 may also function as the calculation unit 114.

[0055] The transceiver 115 has a configuration similar to that of the transceiver 120 provided in the vehicle 100, for example. In this embodiment, when the transceiver 115 receives a control signal transmitted from the transceiver 120, the transceiver 115 transmits the control signal to the control device 111. Furthermore, when information on the angle of the emission direction calculated by the calculation unit 114 is input from the control device 111, the transceiver 115 transmits a signal related to the angle to the outside. The transceiver 120 receives the signal related to the angle transmitted from the transceiver 115 and transmits the signal to the control device 60. In this way, the control signal output from the control device 60 is input to the control device 111, and the signal related to the emission direction of the low beam emitted from the lamp unit 30 is input to the control device 60.

[0056] Next, the calibration of the vehicle headlamp 1 will be described.

[0057] 4 is a flowchart showing an example of the operation of the control device 60 in calibrating the vehicle headlamp 1. A program for executing the operation of this flowchart is stored in the memory 70. Therefore, the control device 60 executes the flowchart of FIG. 4 by reading the program from the memory 70. As shown in FIG. 4, the operation of the control device 60 of this embodiment includes steps S1 to S5. Note that, in the starting state of FIG. 4, as shown in FIG. 1, the vehicle 100 is placed on the floor FL, and the measuring device 110 is placed on the floor FL in front of the vehicle 100 so as to directly face the vehicle headlamp 1 at a predetermined distance.

[0058] <Step S1> This step is a step for acquiring information on the angle of the emission direction of light emitted from the lamp unit 30 in the vertical direction. In this step, first, the control device 60 controls the lamp unit 30 to emit a low beam. Specifically, the control device 60 outputs a control signal to the first power supply circuit 81 to control the first power supply circuit 81, thereby causing the lamp unit 30 to emit a low beam. Next, the control device 60 outputs a control signal to the transceiver unit 120 to instruct the measuring device 110 to perform measurement, and causes the transceiver unit 120 to transmit the control signal. The control signal is received by the transceiver unit 115 of the measuring device 110 and sent to the control device 111. In response to the input of the control signal, the control device 111 measures the emission direction of light emitted from the lamp unit 30. Specifically, the control device 111 causes the light receiving unit 113 to generate image information indicating an image of light irradiated on the light receiving surface 113s and output the image information to the control device 111. Next, the control device 111 outputs this information to the calculation unit 114. The calculation unit 114 extracts the position representing the elbow point EP in the image, calculates the angle of the low beam emission direction in the vertical direction from this position, and outputs information about the calculated angle to the control device 111. The control device 111 outputs the angle information to the transceiver unit 115, which outputs a signal related to this angle. This signal is received by the transceiver unit 120 and sent to the control device 60. In this way, the control device 60 obtains information about the angle of the emission direction of the light emitted from the lamp unit 30 and stores this information in the memory 70, although this information does not necessarily have to be stored in the memory 70. After this step, the control device 60 advances the flow to step S2.

[0059] <Step S2> This step determines the next step depending on the information on the angle of the light emission direction acquired in step S1. In this step, if the angle is outside the target range, the control device 60 advances the flow to step S3. Furthermore, if the angle is within the target range, the control device 60 disables low beam emission from the lamp unit 30 and terminates calibration control. FIG. 5 is a diagram illustrating the target angle and target range in this embodiment. As shown in FIG. 5, the target range TR in this embodiment is a range equal to or greater than the target angle TA minus a predetermined angle and equal to or less than the target angle TA plus the predetermined angle. In this embodiment, the target angle TA is zero degrees, and the predetermined angle is 0.05 degrees. The target angle is the target angle when adjusting the angle of the light emission direction, and the target range is the target range when adjusting the angle of the light emission direction, and these are set in advance. The target angle TA and the predetermined angle are not limited.

[0060] <Step S3> This step determines the next step depending on the information on the angle of the light emission direction acquired in step S1. In this step, if the absolute value of the difference between the angle and the target angle TA is less than the threshold, the control device 60 proceeds to step S4. If the absolute value of the difference between the angle and the target angle TA is greater than or equal to the threshold, the control device 60 proceeds to step S5. Generally, an actuator that can change the orientation of the lamp unit using motor torque may have difficulty finely adjusting the orientation of the lamp unit. The threshold is a value equal to or greater than the angle change that makes it easy for the actuator 50 to change the vertical tilt of the lamp unit 30. For example, the threshold is a value equal to or greater than the change in the tilt angle of the lamp unit 30 when voltage is applied to the motor 52 for a period longer than the time constant of the motor 52. In this embodiment, the threshold is 1.0 degree, which is 10 times the predetermined angle, but the threshold is not limited to this value.

[0061] <Step S4> This step is a step of performing first control, in which the actuator 50 is controlled to adjust the angle of the light emission direction to a first specific angle and then approach the target angle TA. As shown in FIG. 5 , the first specific angle SA1 is an angle whose absolute value of the difference between the first specific angle SA1 and the target angle TA on a plane VP generally parallel to the vertical plane is equal to or greater than a threshold value TH. In this embodiment, the first specific angle SA1 is an angle below the target angle TA, and the absolute value of the difference between the first specific angle SA1 and the target angle TA is equal to or greater than twice the threshold value TH, i.e., 2.0 degrees, but is not limited thereto. For example, the first specific angle SA1 may vary depending on the angle of the light emission direction acquired in step S1. In this step, the control device 60 performs the first control by outputting a control signal to the second power supply circuit 82 to control the second power supply circuit 82. In this embodiment, the control device 60 performs the first control based on the information about the angle of the light emission direction acquired in step S1. After this step, the control device 60 returns the flow to step S1.

[0062] <Step S5> This step is a step of performing second control in which the angle of the light emission direction is changed downward from the target angle TA toward the first specific angle SA1, and then the actuator 50 is controlled to change the angle to a second specific angle and then approach the target angle TA. As shown in FIG. 5 , the second specific angle SA2 is an angle closer to the first specific angle SA1 than the target angle TA, and the absolute value of the difference between the second specific angle SA2 and the target angle TA is equal to or greater than the threshold value TH. In this embodiment, the second specific angle SA2 is an angle below the target angle TA, and the absolute value of the difference from the target angle TA is greater than twice the threshold value TH, i.e., greater than 2.0 degrees. Specifically, when the angle of the light emission direction acquired in step S1 is angle A1 below the target angle TA, the second specific angle SA2 is angle A11, which is lower than angle A1 by the threshold value TH. Furthermore, when the angle of the light emission direction acquired in step S1 is angle A2 above the target angle TA, the second specific angle SA2 is angle A21 below the target angle TA, and the absolute value of the difference between the second specific angle SA2 and the target angle TA is 2.5 degrees, which is greater than twice the threshold value TH. Note that the second specific angle SA2 is not limited. In this step, the control device 60 performs the second control by outputting a control signal to the second power supply circuit 82 to control the second power supply circuit 82. In this embodiment, the control device 60 performs the second control based on the information about the angle of the light emission direction acquired in step S1. After this step, the control device 60 returns the flow to step S1.

[0063] Here, the flow returns to step S1 after step S5, and therefore may proceed to step S4 after step S5. That is, the control device 60 may perform the first control if the absolute value of the difference between the angle of the light emission direction after the second control and the target angle TA is less than the threshold value TH. FIG. 6 is a diagram showing an example of the change over time in the angle of the light emission direction during calibration, specifically, a diagram showing an example of the change over time in the angle of the light emission direction when proceeding to step S4 after step S5. In FIG. 6 , the vertical axis represents angle and the horizontal axis represents time. In this embodiment, in step S4, which is performed after step S5, the control device 60 controls the actuator 50 based on the information on the angle of the light emission direction acquired in step S1 before step S5 and the information on the angle of the light emission direction acquired in step S1 after step S5. Here, the difference between the angle of the light emission direction acquired in step S1 after step S5 and the target angle TA can be considered to be a deviation due to the following influences. Specifically, this difference can be considered to be a deviation caused by the influence of play of the components of the actuator 50 when the angle of the emission direction approaches the target angle TA so that, after changing from the target angle TA in the direction toward the first specific angle SA1, the direction of change is reversed and the angle approaches the target angle TA. For this reason, in this embodiment, in step S4 performed after step S5, the control device 60 assumes that a deviation caused by play occurs by the amount of the difference between the angle of the emission direction of light acquired in step S1 after step S5 and the target angle TA, and controls the actuator 50 so that the target angle TA is an angle that takes this deviation into account. In other words, the actuator 50 is controlled in consideration of the deviation caused by the influence of play.

[0064] In this way, in the calibration of the vehicle headlamp 1 of this embodiment, the acquisition of information on the angle of the light emission direction and one of the first control and the second control are repeated until the angle of the light emitted from the lighting unit 30 becomes an angle within the target range TR.

[0065] As described above, one aspect of the present invention according to this embodiment is a control device 60 for an actuator 50 that can transmit the torque of a motor 52 to the lamp unit 30 and change the orientation of the lamp unit 30 so that the light emission direction is tilted along a plane VP that is approximately parallel to the vertical plane. This control device 60 performs a first control when the absolute value of the difference between the angle of the emission direction and a target angle TA is less than a threshold value TH. The first control is control that sets the angle of the emission direction to a first specific angle SA1, the absolute value of the difference from the target angle TA being equal to or greater than the threshold value TH, and then controls the actuator 50 so that the angle approaches the target angle TA.

[0066] Another aspect of the present invention according to the above embodiment is a program executed by a control device 60 of an actuator 50 that can transmit torque of a motor 52 to the lamp unit 30 to change the orientation of the lamp unit 30 so that the light emission direction is tilted along a plane VP that is approximately parallel to the vertical plane. This program causes the control device 60 to execute a step of performing first control when the absolute value of the difference between the angle of the emission direction and a target angle TA is less than a threshold value TH. The first control is control that sets the angle of the emission direction to a first specific angle SA1, the absolute value of the difference from the target angle TA being equal to or greater than the threshold value TH, and then controls the actuator 50 to approach the target angle TA.

[0067] Yet another aspect of the present invention according to the above embodiment is a vehicle headlamp 1 including a lamp unit 30, an actuator 50, and a control device 60 that controls the actuator 50. The actuator 50 transmits torque from a motor 52 to the lamp unit 30 and changes the orientation of the lamp unit 30 so that the light emission direction is tilted along a plane VP that is generally parallel to the vertical plane. The control device 60 performs a first control when the absolute value of the difference between the emission direction angle and a target angle TA is less than a threshold value TH. The first control is a control that sets the emission direction angle to a first specific angle SA1, the absolute value of the difference from the target angle TA being equal to or greater than the threshold value TH, and then controls the actuator 50 to approach the target angle TA.

[0068] In the control device 60, program, and vehicle headlamp 1 of this embodiment, when the difference between the emission direction angle of light and the target angle TA is less than a threshold value TH, the emission direction angle is set to a first specific angle SA1, the absolute value of the difference from the target angle TA being equal to or greater than the threshold value TH, and then approaches the target angle TA. In other words, the emission direction angle is moved away from the target angle TA and then approaches the target angle TA. Therefore, according to the control device 60, program, and vehicle headlamp 1 of this embodiment, even when the absolute value of the difference between the emission direction angle and the target angle TA is small and it is difficult to directly bring the emission direction angle closer to the target angle TA, the emission direction angle can be brought closer to the target angle TA, and the accuracy of adjustment of the emission direction of light emitted from the lamp unit 30 can be improved.

[0069] The control device 60 of this embodiment performs the second control when the absolute value of the difference between the angle of the emission direction and the target angle TA is equal to or greater than a threshold value TH. The second control is a control that changes the angle of the emission direction from the target angle TA toward a first specific angle SA1, sets it to a second specific angle SA2, and then controls the actuator 50 so that the angle approaches the target angle TA. The second specific angle SA2 is an angle whose absolute value of the difference between the target angle TA and the angle SA2 on the first specific angle SA1 side of the target angle TA is equal to or greater than a threshold value TH. Furthermore, the control device 60 of this embodiment performs the first control described above when the absolute value of the difference between the angle of the emission direction and the target angle TA after the second control is less than the threshold value TH.

[0070] Generally, rattles tend to occur in the components that make up a motor. Furthermore, rattles tend to occur between torque transmission members, such as gears, that transmit motor torque in an actuator. Therefore, due to the influence of such rattles, the angle of the light emission direction may deviate from the target angle even when the actuator is controlled based on the measured light emission direction. In this embodiment, the emission direction angle changes from the target angle TA toward the first specific angle SA1 to the second specific angle SA2, and then approaches the target angle TA. It also changes from the target angle TA toward the first specific angle SA1 to the first specific angle SA1, and then approaches the target angle TA. In other words, in both the first and second angle adjustments, the emission direction angle changes from the target angle TA toward the first specific angle SA1, and then the direction of change is reversed, and it approaches the target angle TA. Therefore, the influence of the rattles described above can be made approximately the same in the first and second adjustments. Furthermore, the difference between the emission direction angle immediately after the emission direction angle is brought closer to the target angle TA for the first time can be considered to be a deviation caused by the influence of backlash when bringing the emission direction angle closer to the target angle TA, as described above. Therefore, as described above, when bringing the emission direction angle closer to the target angle TA for the second time, the actuator 50 can be controlled taking into account the deviation caused by the influence of backlash, and the accuracy of the emission direction adjustment can be further improved.

[0071] In the control device 60 of this embodiment, the absolute value of the difference between the second specific angle SA2 and the target angle TA is greater than the absolute value of the difference between the first specific angle SA1 and the target angle TA. The effect of the aforementioned backlash cannot be detected solely from the emission direction angle before the emission direction angle is first brought closer to the target angle TA. Therefore, to ensure that the emission direction angle changes from the target angle TA toward the first specific angle SA1 to the second specific angle SA2 and then approaches the target angle TA, it is preferable that the absolute value of the difference between the second specific angle SA2 and the target angle TA be large. However, if the absolute value of this difference is large, the period during which the actuator 50 is controlled is likely to be long. As described above, the difference between the emission direction angle and the target angle TA immediately after the emission direction angle is first brought closer to the target angle TA can be considered to be a deviation caused by the aforementioned backlash. Therefore, even if the absolute value of the difference between the first specific angle SA1 and the target angle TA is small, the angle of the emission direction can be changed from the first specific angle SA1 toward the target angle TA to reach the first specific angle SA1, and then approach the target angle TA, thereby shortening the period during which the actuator 50 is controlled. Therefore, according to the control device 60 of this embodiment, it is easier to shorten the period required to adjust the emission direction while suppressing malfunctions in the control of the actuator 50, compared to when the absolute value of the difference between the second specific angle SA2 and the target angle TA is smaller than the absolute value of the difference between the first specific angle SA1 and the target angle TA.

[0072] The absolute value of the difference between the second specific angle SA2 and the target angle TA may be the same as the absolute value of the difference between the first specific angle SA1 and the target angle TA. This configuration can reduce the computational load of the control device 60. The absolute value of the difference between the second specific angle SA2 and the target angle TA may be smaller than the absolute value of the difference between the first specific angle SA1 and the target angle TA. Furthermore, when the absolute value of the difference between the angle of the emission direction and the target angle TA is equal to or greater than the threshold value TH, the control device 60 may perform a control different from the second control. For example, in this case, the control device 60 may control the actuator 50 to change the angle of the emission direction toward the target angle TA so as to approach the target angle TA.

[0073] In the vehicle headlamp 1 of this embodiment, the weight of the lamp unit 30 generates torque in the lamp unit 30 that changes the angle of the emission direction downward, that is, from the target angle TA toward the first specific angle SA1. In the vehicle headlamp 1 of this embodiment, the direction of the torque from the motor 52 transmitted to the lamp unit 30 when the angle of the emission direction approaches the target angle TA from the first specific angle SA1 is opposite to the direction of the torque due to the weight of the lamp unit 30. Therefore, with the above configuration, deviation of the emission direction angle from the target angle TA due to the influence of rattle can be suppressed compared to when the weight of the lamp unit 30 generates torque in the lamp unit 30 that changes the angle of the emission direction from the target angle TA toward the opposite side from the first specific angle SA1. Therefore, the vehicle headlamp 1 of this embodiment can further improve the accuracy of adjustment of the light emission direction. The weight of the lamp unit 30 may generate torque in the lamp unit 30 such that the angle of the emission direction changes from the target angle TA in a direction opposite to the first specific angle SA1.

[0074] Although the present invention has been described above using the above embodiment as an example, the present invention is not limited to this.

[0075] For example, in the above embodiment, the actuator 50 is described as being capable of changing the orientation of the lamp unit 30 so that the light emission direction tilts along a plane VP generally parallel to the vertical plane. However, the actuator 50 may be configured to transmit the torque of the motor 52 to the lamp unit 30 and change the orientation of the lamp unit 30 so that the light emission direction tilts along a predetermined plane. For example, the configuration for transmitting the torque of the motor 52 to the lamp unit 30 is not limited. Furthermore, the predetermined plane is not limited to the plane VP generally parallel to the vertical plane. For example, the actuator 50 may be configured to change the orientation of the lamp unit 30 so that the light emission direction tilts along a plane generally parallel to the horizontal plane. Although not illustrated, an example of such an actuator 50 is a configuration including an output shaft extending in the vertical direction and having an upper end fixed to the lower side of the lamp unit 30. In this case, the torque of the motor 52 rotates the output shaft about its central axis. With this configuration, the direction of light emitted from the lighting unit 30 can be adjusted in the left-right direction along a plane that is roughly parallel to the horizontal plane.

[0076] In the above embodiment, the first specific angle SA1 is an angle below the target angle TA. However, the first specific angle SA1 may be any angle as long as the absolute value of the difference between the first specific angle SA1 and the target angle TA is equal to or greater than the threshold value TH. For example, the first specific angle SA1 may be an angle above the target angle TA. The first specific angle SA1 may also be set according to the angle of the measured emission direction. For example, if the angle of the measured emission direction is on one side relative to the target angle TA, the control device 60 may set the first specific angle SA1 to an angle on one side relative to the target angle TA. If the angle of the measured emission direction is on one side relative to the target angle TA, the control device 60 may set the first specific angle SA1 to an angle on the other side relative to the target angle TA.

[0077] In the above embodiment, the second specific angle SA2 is an angle below the target angle TA. However, the second specific angle SA2 may be any angle as long as the absolute value of the difference between the second specific angle SA2 and the target angle TA on the first specific angle SA1 side of the target angle TA is equal to or greater than the threshold value TH. Therefore, for example, if the first specific angle SA1 is an angle above the target angle TA, the second specific angle SA2 is also an angle above the target angle TA.

[0078] Furthermore, in the adjustment system SY of the above embodiment, the measuring device 110 receives light emitted from the lighting unit 30, measures the emission direction of the light from the lighting unit 30, and outputs a signal related to the emission direction of the light from the lighting unit 30 to the control device 60. However, the device for measuring the emission direction of the light from the lighting unit 30 is not limited to this. For example, if the emission direction of the light changes vertically as the lighting unit 30 tilts along a plane VP that is approximately parallel to the vertical plane as described above, the tilt angle of the lighting unit 30 in the vertical direction is also the angle of the emission direction of the light in the vertical direction. Therefore, for example, a sensor that tilts along the plane VP together with the lighting unit 30 and outputs a signal related to the tilt angle of the lighting unit 30 indirectly measures the angle of the emission direction of the light within the plane VP, and the signal output from the sensor is a signal related to the emission direction of the light. Therefore, such a sensor may output a signal related to the emission direction of the light to the control device 60. An example of such a sensor is a three-axis acceleration sensor attached to the lighting unit 30.

[0079] In the above embodiment, the vehicle lamp is described as a vehicle headlamp 1. However, the vehicle lamp is not limited to a vehicle headlamp, and may be, for example, a road surface drawing device that draws a predetermined image on a road surface by emitting light.

[0080] According to the present invention, a control device, a program, and a vehicle lamp are provided that can improve the accuracy of adjusting the emission direction of light emitted from a lighting unit, and can be used in fields such as vehicle lamps for automobiles, etc.

Claims

1. A control device for an actuator that can change the orientation of a lighting unit by transmitting motor torque to the lighting unit so that the light emission direction is tilted along a specified plane, characterized in that when the absolute value of the difference between the angle of the emission direction and a target angle is less than a threshold value, the control device performs a first control to set the angle of the emission direction to a first specific angle whose absolute value of the difference from the target angle is equal to or greater than the threshold value, and then controls the actuator to approach the target angle.

2. The control device described in claim 1, characterized in that, when the absolute value of the difference between the angle of the emission direction and the target angle is equal to or greater than the threshold value, the angle of the emission direction is changed in a direction from the target angle toward the first specific angle, and a second specific angle is set at which the absolute value of the difference between the target angle and the second specific angle on the first specific angle side of the target angle is equal to or greater than the threshold value, and then a second control is performed to control the actuator so as to approach the target angle.

3. The control device according to claim 2, wherein the first control is performed when the absolute value of the difference between the angle of the emission direction after the second control and the target angle is less than the threshold value.

4. The control device according to claim 3, wherein the absolute value of the difference between the second specific angle and the target angle is greater than the absolute value of the difference between the first specific angle and the target angle.

5. The control device according to claim 1, wherein a signal relating to the angle of the emission direction is input from a measuring device that receives light emitted from the lighting unit and measures the emission direction.

6. A program executed by a control device of an actuator that can transmit motor torque to a lighting unit and change the orientation of the lighting unit so that the light emission direction is tilted along a predetermined plane, characterized in that the program causes the control device to execute a step of performing a first control in which, when the absolute value of the difference between the emission direction angle and a target angle is less than a threshold value, the angle of the emission direction is set to a first specific angle whose absolute value of the difference from the target angle is equal to or greater than the threshold value, and then the actuator is controlled to approach the target angle.

7. A vehicle lamp comprising: a lighting unit; an actuator that can change the orientation of the lighting unit by transmitting motor torque to the lighting unit so that the light emission direction is tilted along a predetermined plane; and a control device that controls the actuator, wherein when the absolute value of the difference between the emission direction angle and a target angle is less than a threshold value, the control device performs first control to set the emission direction angle to a first specific angle whose absolute value of the difference from the target angle is equal to or greater than the threshold value, and then controls the actuator to approach the target angle.

8. The vehicle lamp according to claim 7, wherein the predetermined plane is generally parallel to a vertical plane.

9. A vehicle lamp as described in claim 8, characterized in that the weight of the lamp unit generates a torque in the lamp unit such that the angle of the emission direction changes from the target angle toward the first specific angle.

Images