Calibration method

Abstract

A calibration method for a vehicle headlight (5) including a lamp unit (15) that is capable of changing in orientation in the left-right direction, and a sensor (36) that changes in orientation together with the change in orientation of the lamp unit (15) in the left-right direction and is capable of measuring acceleration in the front-rear and left-right directions of a vehicle (1), the calibration method including: a pseudo-travel step (S31) for causing the vehicle (1) to perform pseudo-travel by using a chassis dynamometer (100) including rollers (111) on which wheels (2) of the vehicle (1) are disposed: an acquisition step (S32) for acquiring acceleration information indicated by a signal output from the sensor (36) during pseudo-travel; a measurement step (S33) for measuring the orientation of the sensor (36) with respect to the front-rear direction of the vehicle (1) on the basis of the acquired acceleration information; and an adjustment step (S34) for changing the orientation of the lamp unit (15) in the left-right direction on the basis of the measured orientation of the sensor (36) with respect to the front-rear direction of the vehicle (1).

Description

Calibration Method

[0001] The present invention relates to a calibration method.

[0002] A vehicle lamp whose orientation of a lamp unit can be changed by an actuator is known. In Patent Document 1 below, a vehicle headlamp which is such a vehicle lamp is disclosed.

[0003] The vehicle headlamp of Patent Document 1 below includes a lamp unit, an actuator, and a control device that controls the actuator. The actuator is configured to be able to change the orientation of the lamp unit in the left - right direction. In this vehicle headlamp, by changing the orientation of the lamp unit in the left - right direction by controlling the actuator by the control device, the orientation of the light emission direction of the lamp unit with respect to the vehicle in the left - right direction is changed. Specifically, the control device corrects the detection value of a three - axis acceleration sensor as an inclination detection device capable of detecting the inclination angle of the vehicle with correction information, and controls the actuator based on this corrected value. The correction information is obtained from the detection value of the acceleration sensor when the vehicle is on a horizontal plane, and the detection value of the acceleration sensor when the vehicle is on a horizontal plane and a load is applied to the front or rear of the vehicle. This correction information is information related to the orientation of the acceleration sensor with respect to the orientation of the vehicle, and calibration of the acceleration sensor is performed with this correction information. Therefore, in Patent Document 1 below, even when the orientation of the acceleration sensor deviates from the design value, the acceleration can be measured taking into account the influence of this deviation, and the control device can accurately control the actuator even in such a case.

[0004] Japanese Patent No. 5947947

[0005] A first aspect of the present invention is a calibration method for a vehicle light fixture, which includes a light fixture unit whose orientation can be changed in the left-right direction, and a sensor whose orientation changes in accordance with the change in the orientation of the light fixture unit and which is capable of measuring the acceleration of a vehicle in the longitudinal and left-right directions, comprising: a simulated driving step in which the vehicle is made to run on a chassis dynamometer which includes rollers for positioning the wheels of the vehicle; an acquisition step in which information on acceleration indicated by a signal output from the sensor is acquired during the simulated driving; a measurement step in which the orientation of the sensor with respect to the longitudinal direction of the vehicle is measured based on the acquired acceleration information; and an adjustment step in which the orientation of the light fixture unit is changed based on the measured orientation of the sensor with respect to the longitudinal direction of the vehicle.

[0006] The inventors discovered that during simulated driving on a chassis dynamometer, the vehicle moves slightly in the longitudinal direction, and further discovered that the vehicle hardly moves in the lateral direction. Based on these discoveries, the inventors found that the graph of the time-dependent change in coordinates indicated by the signal output from the sensor during simulated driving is drawn by a line that is roughly parallel to the direction indicating the longitudinal direction of the vehicle. In the acquisition step of this calibration method, information on the acceleration of the vehicle while it is being simulated on the chassis dynamometer is acquired. Therefore, in the measurement step, information on a line that is roughly parallel to the longitudinal direction of the vehicle can be acquired, and based on this information, the orientation of the sensor relative to the longitudinal direction of the vehicle can be measured. Then, in the adjustment step, based on the measured orientation of the sensor relative to the longitudinal direction of the vehicle, the lateral direction of the light from the lighting unit relative to the vehicle can be adjusted to the desired direction. Accordingly, this calibration method makes it easier to adjust the lateral direction of the light relative to the vehicle compared to measuring the direction of light emission with a measuring instrument or the like.

[0007] In the acquisition step described above, information on acceleration indicated by the signal output from the sensor when the vehicle speed is above a predetermined speed during the simulated driving may be acquired.

[0008] The inventors have discovered that, compared to low-speed conditions such as when starting to drive, vehicles tend to be less likely to move in the left-right direction when their speed is above a certain level. Therefore, with the above configuration, by appropriately setting a predetermined speed, the measurement accuracy of the sensor's orientation relative to the vehicle's front-rear direction can be improved, and the accuracy of adjusting the left-right direction of light relative to the vehicle can be improved.

[0009] In the acquisition step described above, information on acceleration indicated by the signal output from the sensor after a predetermined period of time has elapsed since the start of the simulated driving may be acquired.

[0010] The inventors have discovered that after a certain amount of time has elapsed since the start of driving, the vehicle tends to become less likely to move in the left-right direction compared to immediately after the start of driving. Therefore, with the above configuration, by appropriately setting a predetermined period, the measurement accuracy of the sensor's orientation relative to the vehicle's front-rear direction can be improved, and the accuracy of adjusting the left-right direction of light relative to the vehicle can be improved.

[0011] The simulated driving may be in WLTC (Worldwide-harmonized Light vehicles Test Cycle) mode or JC08 mode.

[0012] WLTC mode and JC08 mode are standards for test methods used to measure vehicle fuel efficiency. Therefore, with this configuration, the lateral direction of light relative to the vehicle can be adjusted during fuel efficiency measurement.

[0013] The adjustment step may be performed while the vehicle is stationary.

[0014] When changing the orientation of a lighting unit using an actuator, vehicle vibrations can affect the actuator's operation. Vehicle vibrations tend to be greater while moving than when stationary. Therefore, the above configuration can reduce the impact of vehicle vibrations on the actuator's operation, allowing for more precise changes in the lighting unit's orientation and improving the accuracy of light direction adjustment. This configuration is therefore useful when changing the orientation of a lighting unit using an actuator.

[0015] Furthermore, a second aspect of the present invention relates to a method for manufacturing a vehicle, comprising: a preparation step of preparing a vehicle equipped with a vehicle lighting fixture; a calibration step of performing calibration of the vehicle lighting fixture, wherein the vehicle lighting fixture includes a lighting unit whose orientation can be changed in the left-right direction, and a sensor whose orientation changes along with the change in the orientation of the lighting unit and which is capable of measuring the acceleration of the vehicle in the longitudinal and left-right directions, and the calibration step is characterized by including: a simulated driving step of causing the vehicle to perform a simulated driving using a chassis dynamometer that includes rollers for positioning the wheels of the vehicle; an acquisition step of acquiring acceleration information indicated by a signal output from the sensor during the simulated driving; a measurement step of measuring the orientation of the sensor with respect to the longitudinal direction of the vehicle based on the acquired acceleration information; and an adjustment step of changing the orientation of the lighting unit based on the measured orientation of the sensor with respect to the longitudinal direction of the vehicle.

[0016] According to this vehicle manufacturing method, it is possible to manufacture a vehicle in which the left-right direction of the light from the vehicle's lighting fixtures can be adjusted.

[0017] As described above, the first and second aspects of the present invention provide a calibration method and a vehicle manufacturing method that can easily adjust the direction of light in the left-right direction relative to the vehicle.

[0018] A third aspect of the present invention is a method for measuring the orientation of a sensor attached to a vehicle and capable of measuring the acceleration of the vehicle in the longitudinal and lateral directions, comprising: a simulated driving step in which the vehicle is made to run in a simulated driving state using a chassis dynamometer that includes rollers for positioning the wheels of the vehicle; an acquisition step in which information on acceleration indicated by a signal output from the sensor is acquired during the simulated driving state; and a measurement step in which the orientation of the sensor with respect to the longitudinal direction of the vehicle is measured based on the acquired acceleration information.

[0019] As described above, the inventors have found that the graph of the time-dependent change in coordinates indicated by the signal output from the sensor during simulated driving is drawn by a line that is generally parallel to the direction indicating the longitudinal direction of the vehicle. In the acquisition step of this measurement method, information on acceleration is acquired when the vehicle is undergoing simulated driving on a chassis dynamometer. Therefore, in the measurement step, information on a line that is generally parallel to the longitudinal direction of the vehicle can be acquired, and based on this information, the orientation of the sensor with respect to the longitudinal direction of the vehicle can be measured. For this reason, this measurement method makes it easier to measure the orientation of the sensor with respect to the longitudinal direction of the vehicle compared to changing the state of the vehicle to multiple different states.

[0020] In the acquisition step described above, information on acceleration indicated by the signal output from the sensor when the vehicle speed is above a predetermined speed during the simulated driving may be acquired.

[0021] According to the above configuration, by appropriately setting a predetermined speed, the measurement accuracy of the sensor's orientation relative to the vehicle's longitudinal direction can be improved.

[0022] In the acquisition step described above, information on acceleration indicated by the signal output from the sensor after a predetermined period of time has elapsed since the start of the simulated driving may be acquired.

[0023] With the above configuration, the measurement accuracy of the sensor's orientation relative to the vehicle's longitudinal direction can be improved by appropriately setting a predetermined period.

[0024] The simulated driving may be driving in WLTC mode or driving in JC08 mode.

[0025] With this configuration, it is possible to measure the orientation of the vehicle relative to the orientation of the sensor while measuring the vehicle's fuel consumption.

[0026] Furthermore, a fourth aspect of the present invention is a calibration method for a sensor attached to a vehicle and capable of measuring the acceleration of the vehicle in the longitudinal and lateral directions, comprising: a simulated driving step in which the vehicle is made to perform a simulated driving on a chassis dynamometer including rollers for positioning the wheels of the vehicle; an acquisition step in which information on acceleration indicated by a signal output from the sensor during the simulated driving is acquired; a measurement step in which the orientation of the sensor with respect to the longitudinal direction of the vehicle is measured based on the acquired acceleration information; and a generation step in which information relating to the orientation of the sensor is generated based on the measured orientation of the sensor with respect to the longitudinal direction of the vehicle.

[0027] This calibration method allows for easy measurement of the sensor's orientation relative to the vehicle's longitudinal direction, similar to the measurement method described above. In the generation step, information related to the sensor's orientation is generated based on the measured sensor orientation relative to the vehicle's longitudinal direction. Therefore, the acceleration measured based on the generated information and the signal from the sensor can be adjusted to account for any mounting errors of the sensor to the vehicle. This allows for sensor calibration and suppresses a decrease in the accuracy of the measured acceleration.

[0028] Furthermore, a fifth aspect of the present invention is a method for manufacturing a vehicle, comprising: a preparation step of preparing a vehicle equipped with a sensor capable of measuring acceleration in the longitudinal and lateral directions; and a calibration step of performing calibration of the sensor, wherein the calibration step includes: a simulated driving step of causing the vehicle to perform a simulated driving on a chassis dynamometer including rollers for positioning the vehicle's wheels; an acquisition step of acquiring acceleration information indicated by signals output from the sensor during the simulated driving; a measurement step of measuring the orientation of the sensor with respect to the longitudinal direction of the vehicle based on the acquired acceleration information; and a generation step of generating information relating to the orientation of the sensor based on the measured orientation of the sensor with respect to the longitudinal direction of the vehicle.

[0029] According to this vehicle manufacturing method, it is possible to manufacture vehicles with calibrated sensors.

[0030] As described above, according to the third to fifth aspects of the present invention, a measurement method, a calibration method, and a vehicle manufacturing method are provided that can easily measure the orientation of a sensor attached to a vehicle.

[0031] Figure 1 is a schematic diagram showing a vehicle and chassis dynamometer in the first embodiment. Figure 2 is a schematic diagram showing the vehicle headlight shown in Figure 1. Figure 3 is a rear view of the lamp unit, support member, and actuator. Figure 4 is a block diagram of the system including the actuator. Figure 5 is a flowchart showing the manufacturing method of the vehicle in the first embodiment. Figure 6 shows the state of the vehicle headlight before adjusting the vertical direction of the light from the lamp unit. Figure 7 shows an example of acceleration acquired in the measurement step. Figure 8 is a schematic diagram showing a vehicle and chassis dynamometer in the second embodiment. Figure 9 is a flowchart showing the manufacturing method of the vehicle in the second embodiment.

[0032] Preferred embodiments of the calibration method, measurement method, and vehicle manufacturing method according to the present invention will be described in detail below with reference to the drawings. The embodiments illustrated below are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified and improved within the scope of the claims. In the drawings referenced below, the dimensions of each component may be shown differently for the sake of clarity. Also, in the drawings, for the sake of readability, reference numerals may be assigned to only some of the similar components, and some reference numerals may be omitted.

[0033] (First Embodiment) Embodiments of the first and second aspects of the present invention will now be described. Figure 1 is a schematic diagram showing a vehicle and a chassis dynamometer in this embodiment. In Figure 1, the vehicle 1 is positioned on the chassis dynamometer 100. First, the vehicle 1 will be described. As shown in Figure 1, the vehicle 1 in this embodiment is a four-wheeled automobile equipped with vehicle headlights 5 as vehicle lighting fixtures.

[0034] Vehicle headlights 5 are generally provided on both the left and right sides of the front of the vehicle 1. In this specification, "right" means the right side in the forward direction of the vehicle 1, and "left" means the left side in the forward direction of the vehicle 1. The left and right vehicle headlights 5 have the same configuration, except that their shape is generally symmetrical in the left-right direction. For this reason, one of the vehicle headlights 5 will be described below.

[0035] Figure 2 is a schematic diagram showing the vehicle headlight 5 shown in Figure 1. As shown in Figure 2, the vehicle headlight 5 of this embodiment mainly comprises a housing 10, a lamp unit 15, a support member 19, and an actuator 20. Note that in Figure 2, the housing 10 is shown in a vertical cross-section.

[0036] The housing 10 includes a lamp housing 11 and a front cover 12. The front of the lamp housing 11 is open, and the front cover 12 is fixed to the lamp housing 11 so as to close this opening. The space formed by the lamp housing 11 and the front cover 12 is a housing space, in which the lighting unit 15, support member 19, and actuator 20 are housed. The front cover 12 transmits the light L emitted from the lighting unit 15. Note that the vertical direction of the light L relative to the vehicle 1 shown in Figure 2 is in the desired direction.

[0037] The lighting unit 15 emits light L towards the front of the vehicle. In this embodiment, the lighting unit 15 mainly consists of a main body 16 equipped with a light source (not shown) and a support part 17. As will be described in detail later, the lighting unit 15 is configured to change its orientation in the vertical and horizontal directions. Note that the internal structure of the main body 16 is not shown in Figure 2.

[0038] The light L emitted from the main body 16 in this embodiment is a low beam. The low beam emitted from the main body 16 is irradiated in front of the vehicle 1 via the front cover 12. The main body 16 may be equipped with a reflector, projection lens, etc., so that the light from the light source has a low beam distribution. For example, an LED (Light Emitting Diode) can be used as the light source. Furthermore, the light L emitted from the main body 16 is not limited and may be a high beam, for example, and the main body 16 may be able to change the light distribution pattern of the emitted light L.

[0039] The support portion 17 is a member that supports the main body portion 16. In this embodiment, the support portion 17 is a heat sink that cools the light source provided in the main body portion 16, and the main body portion 16 is fixed across the upper and front surfaces of the support portion 17. Note that the support portion 17 does not have to be a heat sink, as long as it can support the main body portion 16.

[0040] Figure 3 is a rear view of the lighting unit 15, the support member 19, and the actuator 20. As shown in Figure 3, the support member 17 has an internal space 18 that opens from the rear downwards.

[0041] Figure 4 is a block diagram of the system including the actuator 20. As shown in Figures 2 to 4, the actuator 20 of this embodiment comprises a first output member 21, a second output member 22, a shaft 23, a motor 24, a housing 25, a control device 30, a memory 35, and a sensor 36.

[0042] The first output member 21 rotates about a first rotation axis 21c that is substantially perpendicular to the vertical direction of the vehicle 1 by the torque of the motor 24, and the second output member 22 rotates about a second rotation axis 22c that is substantially parallel to the vertical direction of the vehicle 1 by the torque of the motor 24. In the present embodiment, the actuator 20 can switch between a state in which the first output member 21 rotates and a state in which the second output member 22 rotates, and can rotate the first output member 21 or the second output member 22 by one motor 24. A part of the first output member 21 is located in the accommodation space of the housing 25, and another part of the first output member 21 protrudes from the housing 25 toward the left side. A part of the second output member 22 is located in the accommodation space of the housing 25, and another part of the second output member 22 protrudes from the housing 25 downward. The shaft 23 is located on the right side of the first output member 21 and extends along the first rotation axis 21c. A part of the shaft 23 is located in the accommodation space of the housing 25, and another part of the shaft 23 protrudes from the housing 25 toward the right side. The shaft 23 rotates about the first rotation axis 21c together with the first output member 21.

[0043] The first output member 21 and the shaft 23 are fixed to the support portion 17 of the lamp unit 15, and the actuator 20 is connected to the lamp unit 15. Further, the second output member 22 is fixed to the support member 19. The support member 19 of the present embodiment is a plate-like member fixed to the lamp housing 11, but the support member 19 only needs to support the second output member 22. For example, a part of the lamp housing 11 may be used as the support member 19.

[0044] In such a vehicle headlamp 5, when the first output member 21 and the shaft 23 rotate about the first rotation axis 21c, the vertical inclination of the lamp unit 15 with respect to the vehicle 1 changes, and the vertical direction of the light L with respect to the front-rear direction of the vehicle 1 changes. That is, the actuator 20 can change the vertical inclination of the lamp unit 15 with respect to the front-rear direction of the vehicle 1 so that the vertical direction of the light L changes with respect to the front-rear direction of the vehicle 1.

[0045] Furthermore, as the second output member 22 rotates around the second rotation axis 22c, the left-right orientation of the lighting unit 15 with respect to the front-rear direction of the vehicle 1 changes, and the left-right orientation of the light L with respect to the front-rear direction of the vehicle 1 changes. In other words, the actuator 20 can further change the left-right orientation of the lighting unit 15 with respect to the front-rear direction of the vehicle 1 so that the left-right orientation of the light L changes with respect to the front-rear direction of the vehicle 1.

[0046] In this embodiment, the control device 30, memory 35, and sensor 36 are mounted on a circuit board (not shown) housed in the housing space of the casing 25. This circuit board extends in a direction approximately perpendicular to the first rotation axis 21c and rotates together with the first output member 21 around the first rotation axis 21c. Therefore, the vertical inclination of the control device 30, memory 35, and sensor 36 with respect to the vehicle 1 changes in accordance with the change in the inclination of the lighting unit 15 with respect to the vehicle 1. Furthermore, as the second output member 22 rotates around the second rotation axis 22c, this circuit board rotates around the second rotation axis 22c. Therefore, the left-right orientation of the control device 30, memory 35, and sensor 36 with respect to the vehicle 1 changes in accordance with the change in the left-right orientation of the lighting unit 15 with respect to the vehicle 1.

[0047] The control device 30 consists of, for example, an integrated circuit such as a microcontroller, IC (Integrated Circuit), LSI (Large-scale Integrated Circuit), or ASIC (Application Specific Integrated Circuit), or an NC (Numerical Control) device. Furthermore, when an NC device is used, the control device 30 may or may not use a machine learning machine. In this embodiment, the control device 30 is electrically connected to the motor 24, memory 35, and sensor 36.

[0048] The control device 30 controls the motor 24 of the actuator 20 to change the orientation of the lamp unit 15. When the first output member 21 is rotated by the motor 24, the vertical inclination of the lamp unit 15 changes, and the vertical orientation of the light L changes. Further, when the second output member 22 is rotated by the motor 24, the horizontal orientation of the lamp unit 15 changes, and the horizontal orientation of the light L changes. In the present embodiment, information indicating a desired direction of the light L with respect to the vehicle 1 is stored, and the desired direction includes the vertical orientation with respect to the vehicle 1 and the vertical orientation with respect to the vehicle 1.

[0049] The memory 35 stores information and is configured to be able to read the stored information. The memory 35 is, for example, a non-transitory recording medium, and a semiconductor recording medium such as a RAM (Random Access Memory) or a ROM (Read Only Memory) is suitable, but it may include any form of recording medium such as an optical recording medium or a magnetic recording medium. Note that the "non-transitory" recording medium includes all computer-readable recording media except transitory, propagating signals, and does not exclude volatile recording media. Note that the memory 35 and the control device 30 may be provided in an integrated package. Various programs for controlling the motor 24 and information necessary for such control are stored in the memory 35, and the control device 30 reads the programs and information stored in the memory 35. Further, the memory 35 stores information and the like in accordance with an instruction from the control device 30.

[0050] The sensor 36 is a sensor capable of measuring the acceleration of the vehicle 1 in the front-rear and left-right directions, outputs a signal indicating the acceleration generated in the sensor 36, and the signal is input to the control device 30. The sensor 36 of the present embodiment is a three-axis acceleration sensor and can measure the acceleration in three mutually perpendicular directions. Therefore, the sensor 36 of the present embodiment can measure the acceleration of the vehicle 1 in the front-rear, left-right, and vertical directions. Further, the sensor 36 is also a sensor capable of measuring the direction of the gravitational acceleration as the gravitational direction G. The signal of the sensor 36 includes information that can be converted into a vector such as (x, y, z).

[0051] As described above, the vertical tilt of the sensor 36 relative to the vehicle 1 changes along with the change in the tilt of the lighting unit 15 relative to the vehicle 1. Therefore, the signal indicating the direction of gravitational acceleration as the gravity direction G output from the sensor 36 changes in accordance with the change in the vertical tilt of the lighting unit 15, and is a signal relating to the vertical tilt angle of the lighting unit 15 with respect to the horizontal plane. Since the direction of emission of light L changes vertically with respect to the horizontal plane in accordance with the change in the tilt of the lighting unit 15 with respect to the horizontal plane, the signal from the sensor 36 is also a signal relating to the vertical tilt angle of the emission direction of light L with respect to the horizontal plane. In this embodiment, the information of the signal output from the sensor 36 when the direction of light L emitted from the lighting unit 15 relative to the vehicle 1 is the desired direction and the pitch angle of the vehicle 1 with respect to the horizontal plane is zero includes (xA, yA, zA). This information relates to the desired direction of light L relative to the vehicle 1 and is stored in the memory 35.

[0052] In this embodiment, the x-axis of the coordinate system of the signal from the sensor 36 is parallel to the direction of emission of light L from the lighting unit 15, the y-axis is parallel to the first rotation axis 21c, and the z-axis is perpendicular to the x-axis and y-axis. Therefore, the x-z plane indicates the left-right direction of light L with respect to the orientation of the sensor 36. In this embodiment, the information of the x-z plane is stored in the memory 35 as reference information. In other words, the reference information is information about the left-right direction of light L in the coordinate system of the signal from the sensor 36. Note that the reference information is not limited to information indicating the left-right direction of light L with respect to the orientation of the sensor 36. For example, the reference information may be information about the x-axis. Also, the x-axis may not be parallel to the direction of emission of light L from the lighting unit 15, and the y-axis may not be parallel to the first rotation axis 21c. In this case, as reference information, for example, information relating to a plane that is parallel to the direction of emission of light L from the lighting unit 15 and perpendicular to the first rotation axis 21c in the coordinate system of the signal from the sensor 36 is stored in the memory 35.

[0053] Next, we will explain the chassis dynamometer 100.

[0054] The chassis dynamometer 100 of this embodiment includes a floor plate 105, four roller devices 110, a dynamo control device 120, and a dynamo memory 130. Note that Figure 1 shows two roller devices 110. The roller devices 110 are provided for each of the front, rear, left, and right wheels 2 of the vehicle 1 and include a pair of rollers 111, a load adjustment unit 112, a rotation sensor 113, etc.

[0055] A pair of rollers 111 are fixed to a rotation shaft 114 and are rotatable about the rotation shaft 114. The pair of rollers 111 are arranged at a predetermined distance apart and are exposed through an opening 105h provided in the floor plate 105, and a wheel 2 can be placed on the pair of rollers 111. When the wheel 2 placed on the pair of rollers 111 rotates, the pair of rollers 111 rotate. The load adjustment unit 112 includes a motor (not shown) connected to the rotation shaft 114 of one of the pair of rollers 111, and this motor is controlled by a dynamo control device 120. The rotation sensor 113 is a sensor that measures the rotation speed of the rollers 111 and outputs a signal indicating the rotation speed of the rollers 111.

[0056] The dynamo control device 120, for example, consists of a microcontroller or the like, similar to the control device 30, and controls several components of the chassis dynamometer 100. The load adjustment unit 112, the rotation sensor 113, and the dynamo memory 130 are electrically connected to the dynamo control device 120, and signals from the rotation sensor 113 are input to it.

[0057] The dynamo memory 130 has a configuration similar to, for example, memory 35. The dynamo memory 130 stores programs for controlling several components of the chassis dynamometer 100, as well as information necessary for such control. The dynamo control device 120 reads the programs and information stored in the dynamo memory 130. The dynamo memory 130 also stores information based on instructions from the dynamo control device 120.

[0058] The dynamo control device 120 can adjust the load applied to the wheels 2, which are arranged on a pair of rollers 111, by controlling the motor of the load adjustment unit 112.

[0059] A chassis dynamometer 100 with this configuration can simulate driving a vehicle 1 in which wheels 2 are arranged on a pair of rollers 111. The chassis dynamometer 100 of this embodiment can simulate driving the vehicle 1 in the WLTC mode, JC08 mode, EPA (United States Environmental Protection Agency) mode, NEDC (New European Driving Cycle) mode, and CLTC (China Light-Duty Vehicle Test Cycle) mode, which are standards for test methods that measure the fuel efficiency of vehicles. In other words, the chassis dynamometer 100 can measure the fuel efficiency of the vehicle 1 by driving in these modes, and the dynamo control device 120 can control the load adjustment unit 112 so that the simulated driving is such driving.

[0060] Furthermore, in this embodiment, the pitch angle with respect to the horizontal plane of the vehicle 1, which is positioned on the chassis dynamometer 100 and is stationary when not undergoing simulated driving, is zero. In other words, the positions of the pair of rollers 111 are adjusted to achieve this. Note that the pitch angle of the vehicle 1 in this state does not have to be zero.

[0061] The chassis dynamometer 100 only needs to include rollers for positioning the wheels 2 of the vehicle 1 and be capable of simulating vehicle 1 movement. For example, if the vehicle 1 has only rear wheels 2 as drive wheels, the roller device 110 on which the front wheels 2 are positioned does not need to include a load adjustment unit 112, a rotation sensor 113, etc. Also, the roller device 110 may include only one roller 111, and the wheels 2 may be positioned on this roller 111. Furthermore, the simulated movement of vehicle 1 is not limited to straight-line movement.

[0062] Next, the manufacturing method of the vehicle in this embodiment will be described.

[0063] Figure 5 is a flowchart showing the manufacturing method of the vehicle in this embodiment. As shown in Figure 5, the manufacturing method of the vehicle 1 in this embodiment mainly comprises a preparation step P1, a first calibration step P2, and a second calibration step P3.

[0064] <Preparation Step P1> This step is to prepare a vehicle 1 equipped with vehicle headlights 5. In this embodiment, the vehicle 1 shown in Figure 1 is prepared.

[0065] <First Calibration Step P2> This step is to adjust the vertical direction of the light L emitted from the lamp unit 15 of the vehicle headlight 5. In this embodiment, the vehicle 1 is placed on the chassis dynamometer 100 shown in Figure 1, and the vehicle 1 is placed in a stationary state. In this embodiment, as described above, the pitch angle with respect to the horizontal plane of the stationary vehicle 1 placed on the chassis dynamometer 100 is zero. Figure 6 shows the state of the vehicle headlight 5 before adjusting the vertical direction of the light L from the lamp unit 15, and the vehicle 1 is placed on the chassis dynamometer 100 as described above. In the following description, it will be explained that in this state, the sensor 36 outputs a signal including (x1, y1, z1) as a signal indicating the direction of gravity G.

[0066] As described above, when the direction of light L relative to the vehicle 1 is in the desired direction and the pitch angle of the vehicle 1 with respect to the horizontal plane is zero, the signal information output from the sensor 36 includes (xA, yA, zA), and this information is stored in the memory 35. The control device 30 receives the signal from the sensor 36 and compares (x1, y1, z1) with (xA, yA, zA). The control device 30 then controls the motor 24 of the actuator 20 to rotate the first output member 21 so that (x1, y1, z1) approaches (xA, yA, zA). As the rotation of the first output member 21 changes the vertical tilt of the lighting unit 15 relative to the vehicle 1, as shown by the arrows in Figure 6. Along with the change in the vertical tilt of the lighting unit 15, the vertical tilt of the sensor 36 changes, and the signal indicating the direction of gravity G output from the sensor 36 also changes. The control device 30 drives the motor 24 until the direction indicated by this signal and the direction of (xA, yA, zA) are within a predetermined range. Alternatively, the control device 30 may determine the driving period of the motor 24 from (x1, y1, z1) and (xA, yA, zA) and control the motor 24 accordingly.

[0067] In this way, the vertical orientation of the lighting unit 15 relative to the vehicle 1 changes from the state shown in Figure 6 to the state shown in Figure 2, and the vertical orientation of the light L emitted from the lighting unit 15 is adjusted to the desired vertical orientation.

[0068] <Second Calibration Step P3> This step adjusts the left-right direction of the light L emitted from the lamp unit 15 of the vehicle headlight 5. As shown in Figure 5, this step includes a simulated driving step S31, an acquisition step S32, a measurement step S33, and an adjustment step S34.

[0069] (Simulated Driving Step S31) This step involves making the vehicle 1 perform a simulated drive on a chassis dynamometer that includes rollers on which the wheels 2 of the vehicle 1 are positioned. In this embodiment, the vehicle 1 is made to perform a simulated drive on the chassis dynamometer 100 shown in Figure 1. Specifically, the vehicle 1 is positioned on the chassis dynamometer 100 such that the front, rear, left, and right wheels 2 of the vehicle 1 are positioned on a pair of rollers 111 of the roller device 110. Next, the driver operates the vehicle 1, and the motor of the load adjustment unit 112 is controlled by the dynamo control device 120, thereby making the vehicle 1 perform a simulated drive. In this embodiment, the vehicle 1 is made to drive in WLTC mode as a simulated drive. During the simulated drive, the vehicle 1 moves slightly in the front-to-back direction, but hardly moves in the left-to-right direction.

[0070] (Acquisition Step S32) This step involves acquiring acceleration information indicated by the signal output from the sensor 36 during simulated driving. In this embodiment, the control device 30 acquires acceleration information indicated by the signal output from the sensor 36 when a predetermined period of time has elapsed since the start of the simulated driving and the vehicle speed is above a predetermined speed. For example, the predetermined period is 10 seconds and the predetermined speed is 20 km / h, but the predetermined period and predetermined speed are not limited. Also, the period for acquiring acceleration information is, for example, 30 seconds, but is not limited. In this embodiment, the simulated driving of the vehicle 1 is stopped after acquiring the acceleration information, but the simulated driving may be continued even after acquiring the information. For example, the simulated driving may be continued until the measurement of the fuel consumption of the vehicle 1 by driving in WLTC mode as a simulated driving is completed.

[0071] (Measurement step S33) This step measures the orientation of the sensor 36 relative to the longitudinal direction of the vehicle 1 based on the acceleration information acquired in acquisition step S32. The inventors discovered the longitudinal and lateral behavior of the vehicle 1 during the simulated driving, and based on this discovery, found that the graph of the time-dependent change in coordinates indicated by the signal output from the sensor 36 during the simulated driving is drawn by a line that is roughly parallel to the direction indicating the longitudinal direction of the vehicle 1.

[0072] Figure 7 shows an example of acceleration acquired in measurement step S33. Figure 7 shows the x and y axes of the coordinate system indicated by the signal output from sensor 36, and a vector D1 that is parallel to the longitudinal direction of vehicle 1 and points forward. In this embodiment, the control device 30 approximates the coordinate point indicated by the signal output from sensor 36 to a straight line using the least squares method. This straight line is roughly parallel to the longitudinal direction of vehicle 1. The control device 30 measures the direction parallel to this straight line and pointing forward of vehicle 1. The measured direction is the direction indicating the front of vehicle 1 in the coordinate system of the signal from sensor 36, and also indicates the orientation of sensor 36 with respect to the longitudinal direction of vehicle 1. In other words, the control device 30 measures the above direction as the orientation of sensor 36 with respect to the longitudinal direction of vehicle 1. The control device 30 may also measure the direction parallel to the above straight line and pointing backward of vehicle 1 as the orientation of sensor 36 with respect to the longitudinal direction of vehicle 1. Alternatively, the orientation of sensor 36 with respect to the longitudinal direction of vehicle 1 may be measured using a method other than the least squares method.

[0073] (Adjustment Step S34) This step involves changing the left-right orientation of the lighting unit 15 based on the orientation of the sensor 36 relative to the front-rear direction of the vehicle 1, which was measured in the measurement step S33. In this embodiment, the control device 30 first measures the left-right orientation of the light L relative to the front-rear direction of the vehicle 1 from the orientation of the sensor 36 measured in the measurement step S33 and reference information. Next, the control device 30 controls the motor 24 to rotate the second output member 22 so that the left-right orientation of the light L relative to the front-rear direction of the vehicle 1 approaches the desired left-right orientation. The rotation of the second output member 22 changes the left-right orientation of the lighting unit 15 relative to the vehicle 1. The control device 30 determines the driving period of the motor 24 and controls the motor 24 based on the measured left-right orientation of the light L relative to the front-rear direction of the vehicle 1 so that the difference between the left-right orientation of the light L relative to the vehicle 1 and the desired left-right orientation is within a predetermined range. In this embodiment, as described above, the simulated driving of the vehicle 1 is stopped after acquiring acceleration information. Therefore, this step is performed after the simulated driving and while the vehicle 1 is stationary. Also, if the difference between the measured left-right direction of the light L and the desired left-right direction is within a predetermined range, for example, the control device 30 does not control the motor 24. Note that the control device 30 does not need to measure the left-right direction of the light L with respect to the front-rear direction of the vehicle 1, and does not need to use the above reference information to control the motor 24. For example, if the relationship between the orientation of the sensor 36 and the front-rear direction of the vehicle 1 when the left-right direction of the light L is the desired left-right direction is set in advance, the control device 30 controls the motor 24 so that the relationship between the orientation of the sensor 36 and the front-rear direction of the vehicle 1 becomes this relationship.

[0074] In this way, the left-right orientation of the lighting unit 15 relative to the vehicle 1 is changed based on the orientation of the sensor 36 measured in measurement step S33. Then, the left-right orientation of the light L emitted from the lighting unit 15 is adjusted to the desired left-right orientation.

[0075] Thus, the vehicle headlight 5 is calibrated vertically in the first calibration step P2, and the vehicle headlight 5 is calibrated horizontally in the second calibration step P3. In the second calibration step P3, the orientation of the sensor 36 with respect to the front-rear direction of the vehicle 1 is measured in steps S31, S32, and S33, and the horizontal orientation of the light L is adjusted in step S34. Then, a vehicle 1 with the calibrated vehicle headlight 5 is manufactured. In other words, the method for measuring the orientation of the sensor 36 with respect to the front-rear direction of the vehicle 1 includes steps S31, S32, and S33, and the method for calibrating the vehicle headlight 5 horizontally includes steps S31, S32, S33, and S34.

[0076] Generally, when installing vehicle headlights or during vehicle inspections, the left-right direction of the light emitted towards the vehicle is adjusted. This adjustment is performed, for example, by measuring the light emission direction of the lighting unit with a measuring instrument and controlling the actuator based on the measurement result. There is a demand for a way to easily adjust the left-right direction of light towards a vehicle in this manner.

[0077] Therefore, the calibration method for the vehicle headlight 5 of this embodiment, as a first aspect, comprises a simulated driving step S31, an acquisition step S32, a measurement step S33, and an adjustment step S34. The vehicle headlight 5 includes a lamp unit 15 whose orientation can be changed in the left-right direction, and a sensor 36 whose orientation changes along with the left-right orientation of the lamp unit 15, and which can measure the acceleration of the vehicle 1 in the longitudinal and left-right directions. In the simulated driving step S31, the vehicle 1 is made to drive in a simulated manner using a chassis dynamometer 100 that includes rollers 111 on which the wheels 2 of the vehicle 1 are positioned. As described above, the inventors have found that the graph of the change in coordinates over time indicated by the signal output from the sensor 36 during the simulated driving is drawn by a line that is generally parallel to the direction indicating the longitudinal direction of the vehicle 1. In the acquisition step S32 of this embodiment, information on the acceleration indicated by the signal output from the sensor 36 during the simulated driving is acquired, and in the measurement step S33, the orientation of the sensor 36 with respect to the longitudinal direction of the vehicle 1 is measured based on the acquired acceleration information. Therefore, in the measurement step S33, information about a line that is generally parallel to the front-rear direction of the vehicle 1 can be obtained, and based on this information, the orientation of the sensor 36 with respect to the front-rear direction of the vehicle 1 can be measured. In the adjustment step S34, the orientation of the lighting unit 15 in the left-right direction is changed based on the measured orientation of the sensor 36 with respect to the front-rear direction of the vehicle 1. This change in the lighting unit 15 changes the left-right direction of the light L from the lighting unit 15 with respect to the vehicle 1. Therefore, in the adjustment step S34, the left-right direction of the light L from the lighting unit 15 with respect to the vehicle 1 can be adjusted to a desired direction based on the measured orientation of the sensor 36 with respect to the front-rear direction of the vehicle 1. Accordingly, with the calibration method of this embodiment, the left-right direction of the light L with respect to the vehicle 1 can be easily adjusted compared to when the emission direction of the light L is measured with a measuring instrument or the like.

[0078] It is conceivable to acquire acceleration information indicated by the signal output from sensor 36 during the period when vehicle 1 is accelerating or decelerating in a straight line on a test course, and to measure the orientation of sensor 36 relative to the front-rear direction of vehicle 1 based on the acquired acceleration information. However, the acceleration coordinates acquired in this way tended to vary more in the left-right direction of vehicle 1 than the acceleration coordinates acquired in acquisition step S32 of this embodiment. This is thought to be because vehicle 1 moves in the left-right direction due to the influence of factors such as unevenness of the road surface on which vehicle 1 travels, air resistance during driving, and changes in the scenery outside the vehicle due to driving, which affect the driver's operation of vehicle 1. Therefore, the calibration method of this embodiment can accurately measure the orientation of sensor 36 and improve the accuracy of adjusting the left-right direction of light L relative to vehicle 1, compared to the case where the orientation of sensor 36 is measured by driving vehicle 1 on a test course as described above.

[0079] In the calibration method of this embodiment, in acquisition step S32, acceleration information indicated by the signal output from sensor 36 is acquired during simulated driving when the vehicle speed is above a predetermined speed. The inventors have discovered that, compared to low-speed conditions such as when starting to drive, when the vehicle speed is above a certain level, the vehicle 1 tends to be less likely to move in the left-right direction. Therefore, according to the calibration method of this embodiment, by appropriately setting the predetermined speed, the measurement accuracy of the orientation of sensor 36 with respect to the front-rear direction of vehicle 1 can be improved, and the accuracy of adjusting the left-right orientation of light L with respect to vehicle 1 can be improved. From the viewpoint of improving the measurement accuracy of the orientation of sensor 36, the predetermined speed is preferably 10 km / h or more and 100 km / h or less. Note that in acquisition step S32, acceleration information indicated by the signal from sensor 36 may be acquired regardless of the vehicle speed.

[0080] In the calibration method of this embodiment, in acquisition step S32, acceleration information indicated by the signal output from sensor 36 is acquired during the simulated driving, after a predetermined period of time has elapsed since the start of the driving. The inventors have discovered that after a certain period of time has elapsed since the start of driving, the vehicle 1 tends to be less likely to move in the left-right direction compared to immediately after the start of driving. Therefore, according to the calibration method of this embodiment, by appropriately setting the predetermined period, the measurement accuracy of the orientation of sensor 36 with respect to the front-rear direction of vehicle 1 can be improved, and the accuracy of adjusting the left-right orientation of light L with respect to vehicle 1 can be improved. From the viewpoint of improving the measurement accuracy of the orientation of sensor 36, the predetermined period is preferably 10 seconds or more. Also, if there is a period in the simulated driving where the vehicle is driven at a predetermined speed, acceleration information indicated by the signal output from sensor 36 may be acquired during a specific period that begins 10 seconds or more after the start of that period. Note that in acquisition step S32, the timing of acquiring the acceleration information indicated by the signal from sensor 36 is not limited, and for example, acceleration information may be acquired from immediately after the start of driving.

[0081] In the calibration method of this embodiment, the simulated driving is in WLTC mode. Therefore, according to the calibration method of this embodiment, the left-right calibration of the vehicle headlights 5 can be performed while the fuel consumption of the vehicle 1 is being measured. In addition, from the perspective of performing calibration while the fuel consumption of the vehicle 1 is being measured, the simulated driving may be in JC08 mode, for example.

[0082] When changing the orientation of a lighting unit using an actuator, vehicle vibrations may affect the operation of the actuator. Vehicle vibrations tend to be greater when the vehicle is moving compared to when it is stationary. The vehicle headlight 5 of this embodiment is equipped with an actuator 20 that changes the orientation of the lighting unit 15, and in the calibration method of this embodiment, the adjustment step S34 is performed when the vehicle 1 is stationary. Therefore, according to the calibration method of this embodiment, the influence of vehicle 1 vibrations on the operation of the actuator 20 can be reduced, the orientation of the lighting unit 15 can be changed more accurately, and the adjustment accuracy of the direction of the light L can be improved. For this reason, it is useful when changing the orientation of the lighting unit 15 using an actuator 20, as in this embodiment. Note that the adjustment step S34 may also be performed when the vehicle 1 is moving, for example, when the vehicle 1 is simulated to be moving in the simulated driving step S31. With such a configuration, the time required for calibration of the vehicle headlight 5 can be shortened. Also, the vehicle 1 may be stationary for part of the period during which the actuator is operating in the adjustment step S34, and the vehicle 1 may be moving for other parts of that period.

[0083] Furthermore, the manufacturing method of the vehicle 1 according to this embodiment, as a second embodiment, comprises a preparation step P1 for preparing a vehicle 1 equipped with a vehicle headlight 5, and a second calibration step P3 for performing left-right calibration of the vehicle headlight 5. In the second calibration step P3, the left-right calibration of the vehicle headlight 5 is performed using the calibration method described above. Therefore, according to the manufacturing method of the vehicle 1 according to this embodiment, a vehicle 1 in which the left-right calibration of the vehicle headlight 5 has been performed can be manufactured.

[0084] Although the first and second embodiments of the present invention have been described using the first embodiment as an example, the first and second embodiments of the present invention are not limited thereto.

[0085] For example, in the first embodiment, a vehicle headlight 5 was described as having a lighting unit 15 whose orientation can be changed in the vertical and horizontal directions. However, the lighting unit 15 only needs to be able to change its orientation in the horizontal direction. Also, in the first embodiment, an actuator 20 was described as having the vertical and horizontal orientation of the lighting unit 15 changed by rotating a first output member 21 and a second output member 22 with a single motor 24. However, the configuration of the actuator 20 is not limited. For example, the actuator 20 may have a motor that rotates the first output member 21 and another motor that rotates the second output member 22, or it may not even have a first output member 21. Furthermore, instead of the actuator 20, the vehicle headlight 5 may have an aiming screw that allows the horizontal orientation of the lighting unit 15 to be changed manually.

[0086] Furthermore, in the first embodiment, the control device 30, memory 35, and sensor 36 were described as being mounted on a substrate that rotates together with the first output member 21 around the first rotation axis 21c. However, the position in which the control device 30 and memory 35 are arranged is not limited. For example, they may be arranged outside the housing 25. Also, the sensor 36 only needs to change orientation in accordance with the change in the left-right orientation of the lighting unit 15 and be capable of measuring the acceleration of the vehicle 1 in the front-rear and left-right directions. For example, the sensor 36 may be mounted on a substrate on which the light source of the main body 16 of the lighting unit 15 is mounted, and may be a sensor including a 3-axis accelerometer and a 3-axis gyro sensor, or it may be a 2-axis accelerometer or a 2-axis gyro sensor.

[0087] Furthermore, in the first embodiment, the control device 30 acquired acceleration information indicated by the signal output from the sensor 36 in the acquisition step S32, and measured the orientation of the vehicle 1 relative to the orientation of the sensor 36. However, this acquisition and measurement may be performed by a device other than the control device 30. For example, the dynamo control device 120 of the chassis dynamometer 100 and the sensor 36 may be electrically connected, and the dynamo control device 120 may perform this acquisition and measurement. Alternatively, an operator may perform this acquisition and measurement.

[0088] Furthermore, in the first embodiment, in the adjustment step S34, the control device 30 controlled the actuator 20 based on the orientation of the sensor 36 relative to the front-rear direction of the vehicle 1 measured in the measurement step S33, thereby changing the left-right orientation of the lighting unit 15. However, the control of the actuator 20 may be performed by a device other than the control device 30; for example, the dynamo control device 120 may perform this control. Also, if it is possible to manually change the left-right orientation of the lighting unit 15, an operator may change the left-right orientation of the lighting unit 15.

[0089] Furthermore, in the first embodiment, the first calibration step P2 was described as an example in which the vehicle 1 is placed on a chassis dynamometer 100 and the vertical direction of the light L of the lighting unit 15 is adjusted. However, in the first calibration step P2, it is sufficient to adjust the vertical direction of the light L of the lighting unit 15, and the method of adjustment is not limited. For example, in the first calibration step P2, the vehicle 1 may be placed on a horizontal floor. Also, a device other than the control device 30 may control the actuator 20 to change the vertical tilt of the lighting unit 15, for example, the dynamo control device 120 may control the actuator 20. In addition, if it is possible to manually change the vertical tilt of the lighting unit 15, an operator may change the vertical tilt of the lighting unit 15.

[0090] Furthermore, in the first embodiment, a vehicle headlight 5 was described as an example of a vehicle lighting device. However, the lighting device is not limited to a vehicle headlight 5, and may be a head-up display or projector that projects light onto the windshield.

[0091] (Second Embodiment) Next, a second embodiment, which is the third to fifth aspect of the present invention, will be described. Note that components identical or equivalent to those in the first embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions will be omitted. Figure 8 is a schematic diagram showing the vehicle and chassis dynamometer in this embodiment. In Figure 8, the vehicle 1 is positioned on the chassis dynamometer 100. First, the vehicle 1 will be described. As shown in Figure 8, the vehicle 1 in this embodiment is a four-wheeled automobile equipped with a measurement system 40 and an ECU (Electronic Control Unit) 50. The measurement system 40 in this embodiment includes a measurement unit 41, a memory 42, and a sensor 43.

[0092] The configuration of the measurement unit 41 can be similar to that of the control device 30 in the first embodiment, for example. In this embodiment, the measurement unit 41 is electrically connected to the memory 42, the sensor 43, and the ECU 50. As will be described in detail later, the measurement unit 41 measures the acceleration generated in the vehicle 1.

[0093] The configuration of the memory 42 can be similar to that of the memory 35 in the first embodiment, for example. The memory 42 and the measurement unit 41 may be provided in a single package, or the ECU 50 may also function as the measurement unit 41. The memory 42 stores various programs for measurement and other operations performed by the measurement unit 41, as well as information necessary for such measurement. The measurement unit 41 reads the programs and information stored in the memory 42. The memory 42 also stores information and other data based on instructions from the measurement unit 41.

[0094] Sensor 43 is a sensor capable of measuring the acceleration of the vehicle 1 in the longitudinal and lateral directions, and outputs a signal indicating the acceleration generated by sensor 43. In this embodiment, sensor 43 is mounted so as not to move relative to the vehicle 1, for example, by being mounted on the vehicle body. Sensor 43 in this embodiment is a three-axis acceleration sensor and is capable of measuring acceleration in three directions perpendicular to each other. Therefore, sensor 43 in this embodiment is capable of measuring the acceleration of the vehicle 1 in the longitudinal, lateral, and vertical directions. Sensor 43 is also a sensor capable of measuring the direction of gravitational acceleration as the direction of gravity. The signal from sensor 43 includes information that can be converted into a vector such as (x, y, z). The signal output from sensor 43 changes in accordance with the change in the pitch angle of vehicle 1 with respect to the horizontal plane, and is therefore also a signal related to the pitch angle of vehicle 1 with respect to the horizontal plane. In other words, sensor 43 in this embodiment is also a sensor capable of measuring the pitch angle of vehicle 1 with respect to the horizontal plane.

[0095] The measurement unit 41 measures the acceleration occurring in the vehicle 1 based on the vehicle reference information stored in the memory 42 and the signal from the sensor 43. The vehicle reference information is information indicating the orientation of the vehicle 1 relative to the orientation of the sensor 43, and is information indicating the orientation of the vehicle 1 in the coordinate system of the signal from the sensor 43. In this embodiment, the vehicle reference information is information indicating the front of the vehicle 1 relative to the orientation of the sensor 43, and is information of a vector that is parallel to the front-rear direction of the vehicle 1 and points forward in the coordinate system of the signal from the sensor 43, but is not limited to this. For example, the vehicle reference information may be information indicating the rear of the vehicle 1 relative to the orientation of the sensor 43. Also, the vehicle reference information may be information indicating the left-right direction of the vehicle 1 relative to the orientation of the sensor 43, and this information may include information of a vector that is parallel to the left-right direction of the vehicle 1 and points to the right or left in the coordinate system of the signal from the sensor 43. Since the vehicle reference information is information on the orientation of the vehicle 1 relative to the orientation of the sensor 43, the orientation of the acceleration indicated by the signal from the sensor 43 relative to the vehicle 1 can be determined by the acceleration indicated by the signal from the sensor 43 and the vehicle reference information. The measurement unit 41 measures the acceleration generated in the vehicle 1, including its orientation relative to the vehicle 1, based on vehicle reference information and signals from the sensor 43, and outputs a signal indicating the measured acceleration. In this embodiment, the signal from the measurement unit 41 is input to the ECU 50, and the ECU 50 controls the engine of the vehicle 1, etc., based on this signal. The devices that the ECU 50 controls based on the signal from the measurement unit 41 are not limited. Furthermore, the devices to which the signal from the measurement unit 41 is input are not limited; for example, the signal may be input to a control device different from the ECU 50 provided in the vehicle 1, or it may be input to a control device that controls an actuator that changes the orientation of the headlight unit of the vehicle. The measurement unit 41 may also store the measured acceleration in the memory 42.

[0096] The configuration of the chassis dynamometer 100 in this embodiment is the same as that of the chassis dynamometer 100 in the first embodiment.

[0097] Next, the manufacturing method of the vehicle in this embodiment will be described.

[0098] Figure 9 is a flowchart showing the method for manufacturing a vehicle according to this embodiment. As shown in Figure 9, the method for manufacturing the vehicle 1 according to this embodiment mainly comprises a preparation step P1 and a calibration step P2A.

[0099] <Preparation Step P1> This step is to prepare a vehicle 1 equipped with a sensor 43. In this embodiment, the vehicle 1 shown in Figure 8, which is equipped with a measurement system 40, is prepared. The vehicle reference information stored in the memory 42 is information that is set in advance based on design values, and is information about the orientation of the vehicle 1 relative to the orientation of the sensor 43. Specifically, it is information about a vector that is parallel to the front-rear direction of the vehicle 1 and points forward in the coordinate system of the signal from the sensor 43. In this embodiment, the x, y, and z axes of the coordinate system of the signal from the sensor 43 based on design values ​​are the direction towards the front of the vehicle 1, the direction towards the right of the vehicle 1, and the direction towards the upward of the vehicle 1.

[0100] <Calibration Process P2A> This process is for calibrating the sensor 43 and includes a simulated driving step S21, an acquisition step S22, a measurement step S23, and a generation step S24, as shown in Figure 9.

[0101] (Simulated driving step S21) This step is the same as the simulated driving step S31 of the first embodiment.

[0102] (Acquisition Step S22) This step is to acquire acceleration information indicated by the signal output from the sensor 43 during simulated driving. This step in this embodiment differs from acquisition step S32 in the first embodiment in that the sensor 43 is a sensor capable of measuring acceleration and the measurement unit 41 acquires the acceleration information. For this reason, in the explanation of acquisition step S32, you can simply read sensor 36 as sensor 43 and control device 30 as measurement unit 41, and a detailed explanation of this step will be omitted.

[0103] (Measurement step S23) This step measures the orientation of the sensor 43 relative to the longitudinal direction of the vehicle 1 based on the acceleration information acquired in acquisition step S22. The inventors discovered the longitudinal and lateral behavior of the vehicle 1 during the simulated driving, and based on this discovery, found that the graph of the time-dependent change in coordinates indicated by the signal output from the sensor 43 during the simulated driving is drawn by a line that is roughly parallel to the direction indicating the longitudinal direction of the vehicle 1.

[0104] An example of acceleration obtained in measurement step S23 of this embodiment was the same as an example of acceleration obtained in measurement step S33 of the first embodiment shown in Figure 7. For this reason, the x and y axes in Figure 7 will be described below as the x and y axes of the coordinate system indicated by the signal output from the sensor 43. In this embodiment, the measurement unit 41 approximates the coordinate point indicated by the signal output from the sensor 43 to a straight line using the least squares method. This straight line is generally parallel to the longitudinal direction of the vehicle 1. The measurement unit 41 measures the direction parallel to this straight line and toward the front of the vehicle 1. The measured direction is the direction indicating the front of the vehicle 1 in the coordinate system of the signal from the sensor 43, and also indicates the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1. In other words, the measurement unit 41 measures the above direction as the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1. The measurement unit 41 may also measure the direction parallel to the above straight line and toward the rear of the vehicle 1 as the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1. Alternatively, the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 may be measured using a method other than the least squares method.

[0105] (Generation Step S24) This step generates information relating to the orientation of the sensor 43 based on the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 measured in measurement step S23. In this embodiment, the measurement unit 41 generates vector information indicating the direction measured in measurement step S23 in the coordinate system of the sensor 43. This information relates to the orientation of the sensor 43 and is also vehicle reference information indicating the orientation of the vehicle 1 with respect to the orientation of the sensor 43. In this embodiment, the measurement unit 41 changes the vehicle reference information, which is set in advance based on the design value stored in the memory 42, to the generated information. The measurement unit 41 measures acceleration based on the vehicle reference information thus changed and the signal from the sensor 43, so that the mounting error of the sensor 43 to the vehicle 1 is taken into account in the measured acceleration. Note that the information generated in this step only needs to be information relating to the orientation of the sensor 43 based on the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 measured. For example, the generated information may be correction information that corrects the acceleration measured based on the orientation of the sensor 43, which is measured based on the preset vehicle reference information and the signal from the sensor 43. This correction information is information relating to the deviation of the orientation of the sensor 43 from the design value, and is information relating to the orientation of the sensor 43. In such a case, by measuring the acceleration based on the preset vehicle reference information, the signal from the sensor 43, and the correction information, the measured acceleration can be made to take into account the mounting error of the sensor 43 to the vehicle 1.

[0106] Thus, steps S21, S22, and S23 measure the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1, and step S24 performs calibration of the sensor 43. Then, the vehicle 1 with the calibrated sensor 43 is manufactured. In other words, the method for measuring the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 includes steps S21, S22, and S23, and the method for calibrating the sensor 43 includes steps S21, S22, S23, and S24.

[0107] In the aforementioned Patent Document 1, the orientation of the acceleration sensor relative to the vehicle's orientation is measured by placing the vehicle in two states with different tilt angles. Therefore, there is a need to easily measure the orientation of the acceleration sensor relative to the vehicle's orientation.

[0108] Therefore, the method for measuring the orientation of the sensor 43 in this embodiment, as a third embodiment, comprises a simulated driving step S21, an acquisition step S22, and a measurement step S23. The sensor 43 is attached to the vehicle 1 and is capable of measuring the acceleration of the vehicle 1 in the longitudinal and lateral directions. In the simulated driving step S21, the vehicle 1 is made to drive in a simulated manner using a chassis dynamometer 100 that includes rollers 111 for positioning the wheels 2 of the vehicle 1. As described above, the inventors have found that the graph of the time-dependent change in coordinates indicated by the signal output from the sensor 43 during the simulated driving is drawn by a line that is generally parallel to the direction indicating the longitudinal direction of the vehicle 1. In the acquisition step S22 of this embodiment, information on acceleration indicated by the signal output from the sensor 43 during the simulated driving is acquired, and in the measurement step S23, the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 is measured based on the acquired acceleration information. Therefore, in measurement step S23, information about a line that is generally parallel to the longitudinal direction of the vehicle 1 can be obtained, and based on this information, the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 can be measured. For this reason, the measurement method of this embodiment makes it easier to measure the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 compared to the case where the state of the vehicle 1 is changed to multiple different states.

[0109] It is conceivable to acquire acceleration information indicated by the signal output from sensor 43 during the period when vehicle 1 is accelerating or decelerating in a straight line on a test course, and to measure the orientation of sensor 43 relative to the longitudinal direction of vehicle 1 based on the acquired acceleration information. However, the acceleration coordinates acquired in this way tended to vary more in the lateral direction of vehicle 1 than the acceleration coordinates acquired in acquisition step S22 of this embodiment. This is thought to be because vehicle 1 moves in the lateral direction due to the influence of factors such as unevenness of the road surface on which vehicle 1 travels, air resistance during driving, and changes in the scenery outside the vehicle due to driving, which affect the driver's operation of vehicle 1. For this reason, the measurement method of this embodiment allows for more accurate measurement of the orientation of sensor 43 compared to the method of measuring the orientation of sensor 43 by driving vehicle 1 on a test course, as described above.

[0110] In the measurement method of this embodiment, in acquisition step S22, acceleration information indicated by the signal output from sensor 43 is acquired during simulated driving when the vehicle speed is above a predetermined speed. The inventors have discovered that, compared to low-speed conditions such as when starting to drive, when the vehicle speed is above a certain level, the vehicle 1 tends to be less likely to move in the left-right direction. Therefore, according to the measurement method of this embodiment, the measurement accuracy of the orientation of sensor 43 with respect to the front-rear direction of vehicle 1 can be improved by appropriately setting the predetermined speed. From the viewpoint of improving the measurement accuracy of the orientation of sensor 43, the predetermined speed is preferably 20 km / h or more and 100 km / h or less. Note that in acquisition step S22, acceleration information indicated by the signal from sensor 43 may be acquired regardless of the vehicle speed.

[0111] In the measurement method of this embodiment, in acquisition step S22, acceleration information indicated by the signal output from sensor 43 is acquired during the simulated driving, after a predetermined period of time has elapsed since the start of the driving. The inventors have discovered that after a certain period of time has elapsed since the start of driving, the vehicle 1 tends to be less likely to move in the left-right direction compared to immediately after the start of driving. Therefore, according to the measurement method of this embodiment, the measurement accuracy of the orientation of sensor 43 with respect to the front-rear direction of vehicle 1 can be improved by appropriately setting the predetermined period. From the viewpoint of improving the measurement accuracy of the orientation of sensor 43, the predetermined period is preferably 10 seconds or more. Also, if there is a period in the simulated driving where the vehicle is driven at a predetermined speed, acceleration information indicated by the signal output from sensor 43 may be acquired during a specific period that begins 10 seconds or more after the start of that period. Note that in acquisition step S22, the timing of acquiring the acceleration information indicated by the signal from sensor 43 is not limited, and for example, acceleration information may be acquired from immediately after the start of driving.

[0112] In the measurement method of this embodiment, the simulated driving is driving in WLTC mode. Therefore, according to the measurement method of this embodiment, the orientation of vehicle 1 relative to the orientation of sensor 43 can be measured while the fuel consumption of vehicle 1 is being measured. In addition, from the viewpoint of performing the measurement while the fuel consumption of vehicle 1 is being measured, the simulated driving may be driving in JC08 mode, for example.

[0113] Furthermore, the calibration method for the sensor 43 in this embodiment, as a fourth aspect, comprises a simulated driving step S21, an acquisition step S22, a measurement step S23, and a generation step S24. In the generation step S24, information relating to the orientation of the sensor 43 is generated based on the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 measured in the measurement step S23. According to the calibration method of this embodiment, the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 can be easily measured in the same manner as the measurement method described above. Then, in the generation step S24, information relating to the orientation of the sensor 43 is generated based on the measured orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1. Therefore, the mounting error of the sensor 43 to the vehicle 1 can be taken into account in the acceleration measured based on the generated information and the signal from the sensor 43. In this way, the calibration of the sensor 43 is performed, and a decrease in the accuracy of the measured acceleration can be suppressed.

[0114] Furthermore, the manufacturing method of the vehicle 1 according to this embodiment, as a fifth aspect, comprises a preparation step P1 of preparing a vehicle 1 equipped with a sensor 43 capable of measuring acceleration in the longitudinal and lateral directions, and a calibration step P2A of performing calibration of the sensor 43. In the calibration step P2A, the sensor 43 is calibrated using the calibration method described above. Therefore, according to the manufacturing method of the vehicle 1 according to this embodiment, a vehicle 1 in which the sensor 43 has been calibrated can be manufactured.

[0115] Although the third to fifth aspects of the present invention have been described using the second embodiment as an example, the third to fifth aspects of the present invention are not limited thereto.

[0116] For example, in the second embodiment, the vehicle 1 was equipped with a measuring unit 41 and a memory 42. However, from the viewpoint of measuring the orientation of the sensor 43 with respect to the front-rear direction of the vehicle 1, the measuring unit 41 and the memory 42 do not necessarily have to be provided in the vehicle 1, and may be provided, for example, in a chassis dynamometer 100.

[0117] Furthermore, in the second embodiment, the measurement unit 41 acquired acceleration information indicated by the signal output from the sensor 43 in the acquisition step S22, and measured the orientation of the sensor 43 with respect to the longitudinal direction of the vehicle 1 in the measurement step S23. However, this acquisition and measurement may be performed by a device other than the measurement unit 41. For example, the dynamo control device 120 of the chassis dynamometer 100 and the sensor 43 may be electrically connected, and the dynamo control device 120 may perform this acquisition and measurement. Alternatively, an operator may perform this acquisition and measurement.

[0118] Furthermore, in the second embodiment, in the generation step S24, the measurement unit 41 generated information relating to the orientation of the sensor. However, the generation of this information may be performed by a device other than the measurement unit 41. For example, the dynamo control device 120 and the memory 42 may be electrically connected, and the dynamo control device 120 may generate this information. Alternatively, an operator may generate this information. In addition, the calibration method for the sensor 43 may include a modification step instead of the generation step S24. In this modification step, the orientation of the sensor 43 relative to the orientation of the vehicle 1 may be changed based on the orientation of the sensor 43 relative to the front-rear direction of the vehicle 1 measured in the measurement step S23. In this case, the mounting error of the sensor 43 to the vehicle 1 can be reduced, and the decrease in the accuracy of the measured acceleration can be suppressed. In other words, the sensor 43 is calibrated.

[0119] Furthermore, in the second embodiment, a sensor 43 which is a three-axis acceleration sensor was described as an example. However, the sensor 43 can be any sensor that is attached to the vehicle 1 and capable of measuring the acceleration of the vehicle 1 in the longitudinal and lateral directions. For example, the sensor 43 may be a three-axis gyro sensor, a sensor that includes a three-axis acceleration sensor and a three-axis gyro sensor, or a two-axis acceleration sensor or a two-axis gyro sensor. Also, in the second embodiment, a sensor 43 that is attached to the vehicle body so as not to move relative to the vehicle 1 was described as an example, but the position in which the sensor 43 is attached is not limited. For example, the sensor 43 may be attached so that the orientation of the vehicle 1 with respect to the longitudinal direction can be changed. For example, it may be attached to a lighting unit of a vehicle lighting fixture that has a lighting unit that can change its orientation in the lateral direction. In this case, for example, the orientation of the lighting unit is not changed in the calibration process P2A.

[0120] According to the first and second aspects of the present invention, a calibration method and a method for manufacturing a vehicle are provided that can easily adjust the left-right orientation of light relative to a vehicle. According to the third to fifth aspects, a measurement method, a calibration method, and a method for manufacturing a vehicle are provided that can easily measure the orientation of a sensor attached to a vehicle. These can be used in fields such as automobiles and other vehicles.

Claims

1. A calibration method for a vehicle light fixture, comprising a light fixture unit whose orientation can be changed in the left-right direction, and a sensor whose orientation changes in accordance with the change in the orientation of the light fixture unit and which is capable of measuring the acceleration of a vehicle in the longitudinal and left-right directions, the calibration method comprising: a simulated driving step in which the vehicle is simulated to drive using a chassis dynamometer including rollers for positioning the wheels of the vehicle; an acquisition step in which information on acceleration indicated by a signal output from the sensor is acquired during the simulated driving; a measurement step in which the orientation of the sensor with respect to the longitudinal direction of the vehicle is measured based on the acquired acceleration information; and an adjustment step in which the orientation of the light fixture unit is changed based on the measured orientation of the sensor with respect to the longitudinal direction of the vehicle.

2. The calibration method according to claim 1, characterized in that, in the acquisition step, information on acceleration indicated by the signal output from the sensor during the simulated driving when the vehicle speed is above a predetermined speed is acquired.

3. The calibration method according to claim 1 or 2, characterized in that, in the acquisition step, information on acceleration indicated by the signal output from the sensor after a predetermined period of time has elapsed since the start of the simulated driving is acquired.

4. The calibration method according to claim 1 or 2, characterized in that the simulated driving is driving in WLTC mode or driving in JC08 mode.

5. The calibration method according to claim 1 or 2, characterized in that the adjustment step is performed while the vehicle is stationary.

Images