Vehicular control device

Abstract

To provide a vehicular control device that can reduce calculation errors in calculating a true value of an inclination angle of a vehicle body.SOLUTION: A vehicular control device according to the present invention, which controls an optical axis of a headlight by calculating an inclination angle of a vehicle body, comprises: a determining part that determines whether acceleration information detected by an acceleration sensor and speed information detected by a wheel speed sensor are in a predetermined range or out of the predetermined range; and a calculating part that calculates the inclination angle of the vehicle body on the basis of a plurality of acceleration information and the speed information which both are in the predetermined range. The determining part includes a determining portion that determines whether the above information is in the predetermined range or out of the predetermined range, by determining whether the acceleration information obtained by subjecting at least the acceleration information to temporal differentiation is in the predetermined range or out of the predetermined range.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle control device.

Background Art

[0002] Conventionally, there has been an auto-leveling control technology for controlling the optical axis of a vehicle's headlight. Using the acceleration value obtained by differentiating the vehicle speed calculated from the output of a wheel speed sensor with respect to time, the output value of an acceleration sensor, and the gravitational acceleration, the inclination angle of the road surface (referred to as the road surface inclination angle) and the inclination angle of the vehicle body with respect to the road surface (referred to as the vehicle body inclination angle) are obtained from a predetermined relational expression, and when the inclination angle changes by a predetermined amount, the optical axis of the vehicle's headlight is controlled.

[0003] The auto-leveling control technology described in Patent Document 1 plots the values of the vehicle body acceleration A and the vehicle body inclination angle θv detected during traveling in a two-dimensional coordinate system with the first axis being the vehicle body acceleration A and the second axis being the vehicle body inclination angle θv, and uses the intercept at which the approximate straight line based on the plotted points intersects the first axis (θv) as the true value of the vehicle body inclination angle θv. In this way, auto-leveling control that excludes the influence of nose-up and nose-down of the vehicle body becomes possible.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when calculating the true value of the vehicle body inclination angle including the component of the sensor output when an acceleration change exceeding a predetermined range occurs, such as sudden acceleration, sudden braking, or sudden turning, a calculation error occurs, and the vehicle body inclination angle at that time deviates from the true value. In the conventional configuration, that component cannot be completely removed, and the optical axis of the headlight may not be controlled in the desired direction during traveling.

[0006] An object of the present invention is to provide a vehicle control device capable of reducing a calculation error when calculating the true value of the vehicle body tilt angle.

Means for Solving the Problems

[0007] To achieve the above object, a vehicle control device according to the present invention is a vehicle control device that calculates a vehicle body tilt angle and controls the optical axis of a headlight, and includes acceleration information detected by an acceleration sensor and speed information detected by a wheel speed sensor. A determination unit that determines whether the information is within a predetermined range or outside the predetermined range, and a calculation unit that calculates the vehicle body tilt angle based on a plurality of pieces of the acceleration information and the speed information that are both within the predetermined range. The determination unit includes a determination unit that determines whether the information is within the predetermined range or outside the predetermined range based on whether jerk information obtained by time-differentiating at least the acceleration information is within a predetermined range or outside the predetermined range.

Effects of the Invention

[0008] According to the present invention, it is possible to reduce a calculation error when calculating the true value of the vehicle body tilt angle.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Best Mode for Carrying Out the Invention

[0010] Hereinafter, with reference to the accompanying drawings, a vehicle control device according to an embodiment of the present invention will be described in detail. In the following, "calculation" and "derivation" are used in the same meaning.

[0011] <Embodiment> FIG. 1 is a diagram showing an example of the configuration of a vehicle control device according to an embodiment. The vehicle control device 1 shown in FIG. 1 has a configuration in which a first ECU 11, a second ECU 12, and a third ECU 13 are communicably connected via CAN 10 as an example.

[0012] CAN 10 is a CAN (Controller Area Network) which is an example of an in-vehicle communication network.

[0013] The first ECU 11 is an ECU (Electronic Control Unit) to which an acceleration sensor 21 is connected. The acceleration sensor 21 is a three-axis (X-axis, Y-axis, and Z-axis) sensor as an example. Here, the X-axis is an axis in the longitudinal direction of the vehicle body. The Y-axis is an axis in the lateral direction of the vehicle body. The Z-axis is an axis in the vertical direction of the vehicle body. The acceleration sensor 21 outputs acceleration information X in the X-axis direction, acceleration information Y in the Y-axis direction, and acceleration information Z in the Z-axis direction.

[0014] The second ECU 12 is an ECU (Electronic Control Unit) to which a wheel speed sensor 22 is connected. The wheel speed sensor 22 outputs speed information V.

[0015] The third ECU 13 is an ECU (Electronic Control Unit) that calculates the vehicle body tilt angle θv to be output to the optical axis adjustment unit 23. Here, the vehicle body tilt angle θv refers to the tilt angle of the vehicle body with respect to the road surface. It is assumed that the road surface tilt angle θr is also output to the optical axis adjustment unit 23.

[0016] The third ECU 13 communicates with the first ECU 11 and the second ECU 12, receives the acceleration information X, Y, Z output by the acceleration sensor 21 and the speed information V output by the wheel speed sensor 22 via the CAN 10, and calculates the true value of the vehicle body tilt angle θv from a number of detection values using the acceleration information X, Y, Z and the speed information V as one detection value.

[0017] Specifically, the third ECU 13 has a jerk filter processing unit 100 corresponding to the "determination unit" and a θv calculation unit 200 corresponding to the "calculation unit". In the jerk filter processing unit 100, the detection values received via the CAN 10 are filtered by determining whether they are detection values within a predetermined range, and a plurality of detection values within the predetermined range are used in the process of calculating the true value of the vehicle body tilt angle θv by the θv calculation unit 200.

[0018] Note that the jerk filter processing unit 100 is assumed to include at least a determination unit that determines whether the detection values are within a predetermined range using at least jerk.

[0019] FIG. 2 is a diagram showing an example of the configuration of the processing block of the third ECU 13. As shown in FIG. 2, the jerk filter processing unit 100 has a time differentiator d / dt and a threshold determination unit 110. The acceleration information X, Y, Z and the speed information V, which are the detection values received via the CAN 10, are each time-differentiated by the time differentiator d / dt, and for the acceleration information X, Y, Z, jerk information J-X, jerk information J-Y, jerk information J-Z, speed information V, and vehicle body acceleration information A, the threshold determination unit 110 determines whether they are detection values within a predetermined range.

[0020] As an example, the threshold determination unit 110 uses the thresholds set for each of the acceleration information X, Y, Z, jerk information J-X, J-Y, J-Z, speed information V, and vehicle body acceleration information A to determine in parallel whether the values indicated by the acceleration information X, Y, Z, jerk information J-X, J-Y, J-Z, speed information V, and vehicle body acceleration information A are within a predetermined range. When all the determination results are within the predetermined range, the acceleration information X, acceleration information Z, and vehicle body acceleration information A among the detection values are output to the subsequent stage.

[0021] The θv calculation unit 200 includes an arithmetic unit 210 and an approximate straight line generation unit 220, and calculates the true value of the vehicle body tilt angle θv using the acceleration information X, the acceleration information Z, and the vehicle body acceleration information A among the detected values determined to be within a predetermined range by the threshold determination unit 110.

[0022] The arithmetic unit 210 calculates the vehicle body tilt angle θv by performing calculations on the values of the acceleration information X, the acceleration information Z, and the vehicle body acceleration information A using a predetermined relational expression, and outputs the value of the obtained vehicle body tilt angle θv and the value of the vehicle body acceleration information A used in the calculation.

[0023] The approximate straight line generation unit 220 plots the value of the vehicle body tilt angle θv and the value of the vehicle body acceleration information A output by the arithmetic unit 210 over a predetermined period, generates an approximate straight line based on the plotted plurality of points, and obtains the true value of the vehicle body tilt angle θv. The approximate straight line may be generated by a well-known calculation method such as the least squares method.

[0024] The third ECU 13 controls the optical axis of the headlight by outputting the true value of the obtained vehicle body tilt angle θv and the slope tilt angle θr to the optical axis adjustment unit 23.

[0025] FIG. 3 is an explanatory diagram of the relational expression implemented by the arithmetic unit 210. FIG. 3 shows a state in which the vehicle body 300 of the vehicle is tilted with respect to the road surface 303 as a diagram showing the nose-up or nose-down state of the vehicle. The front and rear wheels 301, 302 of the vehicle are shown in contact with the road surface 303.

[0026] In FIG. 3, the vehicle is traveling parallel to the road surface 303 in the direction of the vector of the vehicle body acceleration information A. The vehicle body tilt angle θv is an angle indicating the magnitude of the nose-up or nose-down of the vehicle body 300 with respect to the direction of the vector of the vehicle body acceleration information A. The vector G is the gravitational acceleration.

[0027] As shown in FIG. 3, the X-axis represents the longitudinal direction of the vehicle body 300, and the Z-axis represents the vertical direction of the vehicle body 300. Note that the Y-axis (not shown) represents the lateral direction of the vehicle body 300. The angle formed by the Z-axis and the vector G is represented by the sum (θr + θv) of the road surface inclination angle θr and the vehicle body inclination angle θv.

[0028] This state is represented by the relational expressions of Equation 1 and Equation 2 through geometric calculations. Note that G in Equation 1 and Equation 2 represents a value of gravitational acceleration.

[0029]

Equation

Equation

[0030] FIG. 4 is an explanatory diagram of the approximate straight line generated by the approximate straight line generation unit 220. In FIG. 4, for the coordinates with the vehicle body acceleration information A on the horizontal axis and the vehicle body inclination angle θv on the vertical axis, it represents the distribution of points obtained by sequentially plotting the values of the vehicle body acceleration information A and the vehicle body inclination angle θv obtained from the detection values in a certain predetermined period.

[0031] In FIG. 4, two types of approximate straight lines are superimposed on the same distribution. One approximate straight line corresponds to the approximate straight line when detection values within a predetermined range are obtained without using the jerk information, and is generated based on the entire point distribution in FIG. 4. The other approximate straight line corresponds to the approximate straight line when detection values within a predetermined range are obtained using the jerk information, and is generated based on the remaining point distribution excluding the component surrounded by the dotted lines N1 and N2 in FIG. 4. Here, the component surrounded by the dotted lines N1 and N2 is an example of the points excluded when using the jerk information, and the component excluded using the jerk information is not limited to this range.

[0032] As shown in Fig. 4, each approximate straight line has a calculation error Δ, and the positions through which they pass are shifted from each other. The inventors of the present application repeated experiments and specified that when jerk information is not used, since the acceleration change is used in the calculation up to the detection value when it exceeds a predetermined range, it becomes a factor in the shift of the approximate straight line. And they came to the conclusion that using the distribution when jerk information is used reduces the components (noise) that cause calculation errors, and it becomes possible to derive the true value of the vehicle body tilt angle θv with less influence of nose-up or nose-down.

[0033] Here, the true value of the vehicle body tilt angle θv with less influence of nose-up or nose-down is the value of the intercept where the approximate straight line intersects the vertical axis in Fig. 4. As shown in Fig. 4, since the two types of approximate straight lines have calculation errors in the approximate straight line with noise, it can be seen that the values of the intercepts do not match.

[0034] Next, the threshold value set in the threshold determination unit 110 will be described. In the threshold determination unit 110, a threshold value for determining whether the detected value is within a predetermined range is set in advance. In the present embodiment, for the acceleration information X, Y, Z, jerk information J-X, jerk information J-Y, jerk information J-Z, speed information V, and vehicle body acceleration information A, thresholds are set respectively to determine whether they are within a predetermined range. Here, the threshold values of each of the jerk information J-X, J-Y, J-Z, which is one of them, will be described.

[0035] The threshold determination unit 110 sets in advance a threshold value for determining whether the detected value is within a predetermined range based on the jerk information, and performs a threshold determination as to whether it is within a predetermined range from the jerk information J-X, J-Y, J-Z obtained by differentiating the acceleration information X, Y, Z obtained during running with respect to time respectively.

[0036] The threshold value is set based on the range that the jerk value recorded by running the vehicle in a steady state for a predetermined time or more normally takes. Here, steady state running refers to running that repeats deceleration and acceleration within the range from 0 km / h to a predetermined speed.

[0037] FIG. 5 is a diagram showing an example of a method for determining a jerk information threshold value. FIG. 5 shows a graph of the standard deviation of the jerk values recorded by driving the vehicle at a steady speed for a predetermined time or more.

[0038] When using the standard deviation as shown in FIG. 5, a predetermined range is set as the first threshold value Th1 and the second threshold value Th2 from both ends so that the mountain range, which is the range that the jerk value typically takes in steady driving, remains. By setting these first threshold value Th1 and second threshold value Th2, jerk information having a value from one end side of the first threshold value Th1 or from the other end side of the second threshold value Th2 is specified, and the detection value for the specified jerk information is excluded.

[0039] FIG. 6 is a diagram showing a change in the point distribution when using jerk information. In FIG. 6, a predetermined range is excluded from the point (0, 0) because the calculation accuracy deteriorates.

[0040] As shown in FIG. 6, by performing the jerk filter process, the distribution of white points decreases and the distribution of black points remains compared to the case where the jerk filter process is not performed. The black points are distributed inside the distribution of the white points, indicating that components leading to calculation errors can be removed.

[0041] Subsequently, the optical axis control procedure of the headlight by the vehicle will be described. The vehicle performs optical axis control of the headlight at an optical axis control angle based on the road surface inclination angle θr and the vehicle body inclination angle θv. Hereinafter, the angle formed by the Z-axis, which is the vertical direction of the vehicle body, and the vertical direction, which is the direction of the gravitational acceleration G, is defined as the sensor angle (inclination angle), and the angle formed by the X-axis, which is the front direction of the vehicle body at that time, and the optical axis direction of the headlight is defined as the optical axis control angle for explanation.

[0042] Due to the change in the vehicle body inclination angle θv, the sensor angle changes from Tθs to θs, and the optical axis control angle changes from TLact to Lact. Expressing these relationships in an equation gives the following equation 3. Here, θs - Tθs is the change amount of the sensor angle.

[0043] Lact = TLact + (θs - Tθs) ··· (Equation 3)

[0044] FIG. 7 is a diagram showing an example of a headlight optical axis control flow by a vehicle. As shown in FIG. 7, first, the vehicle determines whether or not the vehicle is in motion (step S1). Whether or not the vehicle is in motion is determined from, for example, the vehicle speed information V of the wheel speed sensor 22 and the like.

[0045] If the vehicle is in motion (step S1: Yes), the processes of steps S2 to S7 are performed. If the vehicle is not in motion (step S1: No), the process proceeds to step S8 and the process is performed. First, since the vehicle is initially stationary, the process will be described starting from step S8.

[0046] When the vehicle is stationary, the vehicle performs the optical axis control process at the time of vehicle stop. First, the vehicle determines whether it is the first stop (step S8). If the vehicle determines that it is the first stop (step S8: Yes), it derives the sensor angle Tθs and the optical axis control angle TLact from the first stop during driving (step S9), and then proceeds to step S3 to avoid performing optical axis control.

[0047] On the other hand, if the vehicle does not determine that it is the first stop (step S8: No), that is, after the first stop, the vehicle detects the sensor angle θs during stop (step S10), and uses the detected sensor angle θs, the previous sensor angle Tθs derived in step S9, and the previous optical axis control angle TLact to perform the calculation of Equation 3 to calculate the optical axis control angle Lact during stop (step S11).

[0048] After the process of step S11, the vehicle determines whether or not the optical axis control angle Lact calculated in step S11 has changed by a predetermined amount or more from the previous optical axis control angle (step S11). Here, the predetermined amount is a value determined by, for example, the hardware limitations of the actuator that controls the optical axis of the headlight.

[0049] If the vehicle determines that the optical axis control angle Lact has not changed by a predetermined amount or more from the previous optical axis control angle (step S12: No), the process proceeds to step S3 to avoid optical axis control.

[0050] On the other hand, when the vehicle determines that the optical axis control angle Lact has changed by a predetermined amount or more from the previous optical axis control angle (step S12: Yes), it performs optical axis control based on the calculated optical axis control angle Lact (step S13), and ends the optical axis control process of the headlight when the vehicle stops.

[0051] Next, the optical axis control process of the headlight when the vehicle is running (step S1: Yes) will be described. First, the vehicle determines whether the vehicle is accelerating or decelerating based on the vehicle body acceleration A (step S2).

[0052] When the vehicle determines that the vehicle is not accelerating or decelerating (step S2: No), since the vehicle body tilt angle θv cannot be calculated, it proceeds to step S3 to avoid optical axis control.

[0053] On the other hand, when the vehicle determines that the vehicle is accelerating or decelerating (step S2: Yes), it determines whether the detected value detected during acceleration or deceleration is data to be filtered (step S4). Specifically, the vehicle derives jerk information from the detected value detected during acceleration or deceleration, and determines whether the detected value is data outside a predetermined range for which filtering is required based on the derived jerk information.

[0054] When the vehicle determines that the detected value detected during acceleration or deceleration is data to be filtered (step S4: Yes), it proceeds to step S3.

[0055] On the other hand, when the vehicle determines that the detected value detected during acceleration or deceleration is not data to be filtered (step S4: No), it calculates the vehicle body tilt angle θv including the detected value in the data (step S5).

[0056] Subsequently, the vehicle determines whether the calculated vehicle body tilt angle θv has changed by a predetermined amount (step S6). This determination corresponds to the determination in step S12. In step S6, the vehicle determines whether the currently calculated vehicle body tilt angle θv has changed by a predetermined amount by comparing it with the previously calculated vehicle body tilt angle θv.

[0057] When the vehicle determines that there is no change in the vehicle body tilt angle θv by a predetermined amount (step S6: No), it proceeds to step S3. Also, when the vehicle determines that there is a change in the vehicle body tilt angle θv by a predetermined amount (step S6: Yes), based on the vehicle body tilt angle θv after the change, it performs optical axis control by that amount of change (step S7). For example, based on the vehicle body tilt angle θv after the change, the vehicle updates the position and reference value of the optical axis by that amount of change, and performs optical axis control based on the updated position and reference value of the optical axis. Then it proceeds to step S3.

[0058] In this embodiment, threshold values are set for the acceleration information X, Y, Z, the jerk information J-X, the jerk information J-Y, the jerk information J-Z, the speed information V, and the vehicle body acceleration information A, but this is just an example. Some of these may be applied. For example, at least one of the jerk information J-X, the jerk information J-Y, and the jerk information J-Z may be included.

[0059] Also, in this embodiment, the third ECU 13 communicates with the first ECU 11 and the second ECU 12, and receives the acceleration information X, Y, Z output by the acceleration sensor 21 and the speed information V output by the wheel speed sensor 22 via the CAN 10. However, a configuration in which the acceleration sensor 21 and the wheel speed sensor 22 are connected to the third ECU 13 side may also be used.

[0060] Also, the configuration of the third ECU 13 may be composed of a plurality of ECUs.

[0061] Also, the arithmetic expressions (Expression 1, Expression 2) are just examples, and may be appropriately modified and used.

[0062] Also, although a three-axis acceleration sensor is used for the acceleration sensor, a two-axis acceleration sensor for front-rear and up-down directions may be used, or two one-axis acceleration sensors for front-rear and up-down directions may be provided.

[0063] Further, as the acceleration sensor, an acceleration sensor already mounted on the vehicle for anti-skid control or the like may be used. As a result, it is not necessary to provide an acceleration sensor dedicated to the optical axis control of the headlight, and the cost can be reduced.

[0064] Further, as a means for obtaining the road surface inclination angle θr, a navigation system or the like may be used.

[0065] In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

[0066] In the threshold determination of the present embodiment, at least one or more of the threshold determinations of the jerk information J-X, the jerk information J-Y, and the jerk information J-Z are included. Therefore, it is possible to accurately remove the components of the sensor output in the case of sudden acceleration, sudden braking, sudden turning, etc. In this case, the calculation error is reduced, and the true value of the vehicle body inclination angle can be stably obtained regardless of the driving state, so that the accuracy of the optical axis control of the headlight during driving is also stabilized.

[0067] Note that the present invention is not limited to the above-described embodiment, and various modifications other than the above can be made without departing from the spirit of the invention.

Explanation of Signs

[0068] 1 Vehicle control device 10 CAN 11 First ECU 12 Second ECU 13 Third ECU 21 Acceleration sensor 22 Wheel speed sensor 100 Jerk filter processing unit 200 θv calculation unit 210 Calculation unit 220 Approximate straight line generation unit

Claims

1. A vehicle control device that calculates a vehicle body tilt angle and controls the optical axis of a headlight, comprising: a determination unit that determines whether acceleration information detected by an acceleration sensor and speed information detected by a wheel speed sensor are within a predetermined range or outside the predetermined range; a calculation unit that calculates the vehicle body tilt angle based on a plurality of pieces of the acceleration information and the speed information that are both within the predetermined range; and having the determination unit includes a determination unit that determines whether it is within the predetermined range or outside the predetermined range based on whether jerk information obtained by time-differentiating at least the acceleration information is within a predetermined range or outside the predetermined range; A vehicle control device characterized by the above.

2. The determination unit determines whether the jerk information is within a predetermined range or outside the predetermined range based on a threshold value, the threshold value is set from within a range taken by the jerk value when the vehicle travels steadily for a predetermined time or more, The vehicle control device according to claim 1, characterized by the above.

Images