Vehicle control device

Abstract

To provide a vehicle control device that is able to quickly and accurately determine whether a vehicle is in a stopped state or in a traveling state, by using a wheel speed pulse.SOLUTION: In a case where a wheel speed pulse is continuously acquired only from a specific wheel in a state where wheel speed pulses not acquired from wheels other than some specific wheels of a plurality of wheels of a vehicle, and in a case where a first time or more has elapsed since the wheel speed pulse is last acquired from the wheel other than the specific wheel when the continuous wheel speed pulse is acquired, an erroneous detection determination flag indicating a state where the wheel speed pulse is erroneously acquired from the specific wheel is turned on; and in a state where the erroneous detection determination flag is turned on, it is considered that the wheel speed pulse is not acquired from the specific wheel, and a stop state and a traveling state are determined.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device that determines whether a vehicle is in a stopped state or a running state. [Background technology]

[0002] Wheel speed sensors have been used for detecting the speed of a vehicle and determining whether the vehicle is stationary or moving. A wheel speed sensor has a concave-convex surface formed on a rotor that rotates integrally with the wheel, a pre-magnetized electrode positioned opposite the concave-convex surface, and a coil arranged around the electrode. When the concave-convex surface moves relative to the electrode, the magnetic flux density of the magnetic field lines generated around the electrode changes, generating a voltage in the coil. This voltage change is converted into a pulse signal (hereinafter referred to as a wheel speed pulse) and output.

[0003] Here, even when the vehicle is stopped, if an electrode is located near the boundary between the rotor's concave and convex portions, slight wheel movement, such as when the steering wheel is turned or the vehicle body vibrates, may cause a wheel speed pulse to be output. Therefore, determining whether the vehicle is in a moving or stopped state based solely on the presence or absence of a wheel speed pulse output has the problem of inaccurate determination. Therefore, Japanese Patent Application Laid-Open Publication No. 2018-20723 describes a technology that counts the number of edges of wheel speed pulses output from each wheel within the last three seconds, for example, and determines that the vehicle is in a moving state if two or more edges are counted for three or more wheels, and otherwise determines that the vehicle is in a stopped state. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-20723 A (paragraphs 0013-0014) Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology of Patent Document 1, since it determines whether the vehicle is stopped or moving based on the number of counts of pulses output from each wheel within a certain period, it takes a certain period of time, for example, from when the vehicle actually stops until it is determined that the vehicle is stopped, and from when the vehicle actually starts moving until it is determined that the vehicle is moving. As a result, there is a time lag before the device can grasp the change in the vehicle's state, which has led to the problem that it is not possible to provide appropriate driving assistance or vehicle control.

[0006] The present invention has been made to solve the above-mentioned problems in the conventional technology, and aims to provide a vehicle control device that can determine whether a vehicle is stopped or running using wheel speed pulses more quickly and accurately than conventional devices. [Means for solving the problem]

[0007] In order to achieve the above object, the vehicle control device of the present invention comprises: a wheel speed pulse acquisition means for acquiring wheel speed pulses output in association with the rotation of each of a plurality of wheels provided on the vehicle, separated for each of the plurality of wheels provided on the vehicle, and the wheel speed pulses acquired by the wheel speed pulse acquisition means; a vehicle speed detection means for calculating the vehicle speed of the vehicle based on the wheel speed pulses acquired by the wheel speed pulse acquisition means; a vehicle behavior determination means for determining whether the vehicle is in a stopped state or a running state based on the vehicle speed calculated by the vehicle speed detection means and the wheel speed pulses acquired by the wheel speed pulse acquisition means; and an erroneous detection determination means for turning on an erroneous detection determination flag indicating that wheel speed pulses have been erroneously acquired from the particular wheel when wheel speed pulses have not been acquired from wheels other than some specific wheels among the plurality of wheels provided on the vehicle, and when more than a first time has passed since the last acquisition of wheel speed pulses from wheels other than the particular wheel.When the erroneous detection determination flag is on, the vehicle behavior determination means determines whether the vehicle is in the stopped state or the running state, assuming that wheel speed pulses have not been acquired from the particular wheel. [Effects of the Invention]

[0008] With the vehicle control device according to the present invention having the above configuration, by identifying in advance using an erroneous detection determination flag when a wheel speed pulse may be erroneously acquired, it is no longer necessary to determine whether the vehicle is stopped or moving after a certain period of time, as has been the case in the past. As a result, when determining whether the vehicle is stopped or moving using the wheel speed pulse, it is possible to make the determination more quickly and accurately than in the past. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a vehicle according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of the arrangement of wheel speed sensors on a vehicle. [Figure 3] 1 is a block diagram showing a configuration of a vehicle control device according to an embodiment of the present invention; [Figure 4] 4 is a flowchart of a vehicle information detection processing program according to the present embodiment. [Figure 5] 4A and 4B are diagrams showing an example of changes in wheel speed pulses input from four wheels when the vehicle is in a running state and a stopped state. [Figure 6] FIG. 10 is a diagram illustrating a method for determining an erroneous detection determination flag. [Figure 7] 10A and 10B are diagrams illustrating a case where an erroneous detection determination flag is turned on. [Figure 8] FIG. 10 is a diagram illustrating a vehicle stop determination. [Figure 9] FIG. 10 is a diagram illustrating a determination of a vehicle's start of traveling. DETAILED DESCRIPTION OF THE INVENTION

[0010] A detailed description will be given below of a specific embodiment of a vehicle control device according to the present invention with reference to the drawings. First, a vehicle 2 equipped with a vehicle control device 1 according to this embodiment will be described below. Figure 1 is a schematic diagram of the vehicle 2 according to this embodiment.

[0011] Here, the vehicle 2 may be, for example, an automobile (internal combustion engine automobile) that uses an internal combustion engine (engine, etc.) as a drive source, an automobile (electric automobile, fuel cell automobile, etc.) that uses an electric motor (motor, etc.) as a drive source, or an automobile that uses both of these as a drive source (hybrid automobile). Furthermore, the vehicle type is not limited, and it may be a standard car, or a large commercial truck, bus, construction machinery, etc. Furthermore, although the following description will be of a four-wheeled automobile, it may also be a two-wheeled or three-wheeled vehicle.

[0012] However, vehicle 2 may be a vehicle capable of only manual driving based on the driving operation of the user, or a vehicle capable of assisted driving with automated driving assistance, in which the vehicle drives automatically without the driving operation of the user. Furthermore, automated driving assistance may be performed only under specific circumstances, such as when parking or leaving a parking lot, or may be performed for all road sections, or may be performed only while the vehicle is traveling on a specific road section (for example, a highway with a gate (manned or unmanned, toll or free) at the boundary).

[0013] 1, the vehicle 2 includes a steering wheel 4 that is operated by the occupant, a power steering device 5 that assists in steering the steering wheel 4, four wheels 6A-6D (front, rear, left, and right), rotors 7A-7D that rotate integrally with the wheels 6A-6D, wheel speed sensors 8A-8D installed in positions facing the uneven surfaces formed on the rotors 7A-7D, a liquid crystal display 9 that displays vehicle speed information, bird's-eye and overhead images of the vehicle's surroundings, and other driving assistance information to the occupant, and a vehicle control ECU (electronic control unit) 10 that performs various calculations based on input information. The vehicle control device 1 includes the vehicle control ECU 10 and other components.

[0014] Each component of the vehicle 2 will be described below. First, the steering wheel 4 is installed in the driver's seat and is a rudder that the occupant grasps and turns to change the traveling direction of the vehicle 2. Basically, to change the traveling direction to the right, the steering wheel 4 is turned to the right (clockwise), and to change the traveling direction to the left, the steering wheel 4 is turned to the left (counterclockwise). A power steering device 5 is connected to a steering shaft connected to the steering wheel 4, and with assistance from the power steering device 5, a rack gear and pinion gear at the tip of the steering shaft are driven in response to the turning of the steering wheel 4, thereby displacing the steering angle of the front wheels 6A, 6B in a direction corresponding to the turning direction of the steering wheel 4.

[0015] The wheels 6A to 6D are rotated by a drive source (for example, an engine or a motor) mounted on the vehicle 2, causing the vehicle 2 to travel in a specified direction. Although not shown, a transmission mechanism, such as a transmission, for transmitting the torque of the drive source to the wheels 6A to 6D is also provided between the drive source and the wheels 6A to 6D. Hereinafter, the wheels will be described as a left front wheel 3A, a right front wheel 3B, a left rear wheel 3C, and a right rear wheel 3D.

[0016] Rotors 7A to 7D are provided on rotating parts such as drive shafts, axle hubs, and brake drums for each of the wheels 6A to 6D, and rotate integrally with the wheels 6A to 6D. Fig. 2 shows rotors 7A to 7D provided on the wheels 6A to 6D, and as shown in Fig. 2, rotors 7A to 7D have an uneven shape on their outer peripheries.

[0017] On the other hand, the wheel speed sensors 8A-8D are installed at positions facing the uneven surfaces formed on the rotors 7A-7D, which rotate integrally with the wheels 6A-6D, as shown in FIG. 2, and are sensors that detect the rotational speed of each wheel as a signal. Specifically, each sensor has a pre-magnetized electrode and a coil arranged around the electrode. When the uneven surface moves relative to the electrode, the magnetic flux density of the magnetic field lines generated around the electrode changes, generating a voltage in the coil. This voltage change is converted into a pulse signal (wheel speed pulse) and output to the vehicle control ECU 10. The vehicle control ECU 10 can then detect the wheel speed of each wheel based on the input wheel speed pulse. Furthermore, the vehicle speed is calculated based on the wheel speed of each wheel or the integrated value of the wheel speed pulse, and further, based on the calculated vehicle speed and the amount of change in the wheel speed pulse, it is also possible to determine whether the vehicle is stationary or moving. This will be described in detail later.

[0018] Although the above example describes the electromagnetic pickup type wheel speed sensors 8A to 8D, semiconductor type wheel speed sensors may also be used. Examples of semiconductor type wheel speed sensors include ferromagnetic resistance type, Hall element type, and Hall IC type.

[0019] The liquid crystal display 9 is mounted on the instrument panel of the vehicle 2 and displays the current vehicle speed calculated by the vehicle control ECU 10 based on the wheel speed pulses. However, an analog meter may also be used to display the vehicle speed. Furthermore, it is also possible to display bird's-eye and overhead images of the vehicle's surroundings, which are generated by subjecting images captured by a camera mounted on the vehicle body to viewpoint conversion and synthesis processing, as needed.

[0020] Meanwhile, the vehicle control ECU 10 is an electronic control unit that performs various processes related to the vehicle 2. The vehicle control ECU 10 may be a single ECU or a combination of multiple ECUs. The vehicle control ECU 10 detects the wheel speed of each wheel based on the wheel speed pulses input from the wheel speed sensors 8A to 8D. Furthermore, the vehicle control ECU 10 executes vehicle control, such as vehicle dynamics control (VDC) and anti-lock brake system (ABS), based on the detected wheel speed of each wheel. The vehicle control ECU 10 calculates the vehicle speed based on the integrated value of the wheel speed or wheel speed pulses of each wheel, and further determines whether the vehicle is stopped or moving based on the calculated vehicle speed and the amount of change in the wheel speed pulse. The determination result of whether the vehicle is stopped or moving is used, for example, for brake fluid pressure increase control or brake fluid pressure decrease control. Furthermore, when autonomous driving assistance is performed, the determination result of whether the vehicle is stopped or moving can be reflected in the control of the autonomous driving assistance, thereby enabling more appropriate control. On the other hand, when performing autonomous driving assistance, for example, the vehicle control ECU 10 constantly detects the current position of the vehicle, the lane the vehicle is traveling on, and the positions of surrounding obstacles, and controls the vehicle, such as steering, drive source, and brakes, so that the vehicle travels along the generated travel trajectory at a speed according to the generated speed plan. The vehicle control ECU 10 is connected to the above-mentioned power steering device 5, wheel speed sensors 8A to 8D, and LCD display 9 via an in-vehicle network such as a CAN. It is also connected to various sensors other than the wheel speed sensors 8A to 8D mounted on the vehicle 2, such as acceleration sensors, gyro sensors, steering sensors, and shift position sensors, as well as to an in-vehicle device such as a navigation device. The detailed configuration of the vehicle control ECU 10 will be described later.

[0021] In addition, the vehicle 2 has basic components as a vehicle 2 in addition to the components shown in Figure 1, but we will only explain the configuration related to the detection control of vehicle speed and driving state, and the control related to this configuration.

[0022] Next, a detailed description will be given of the vehicle control ECU 10 in particular of the vehicle control device 1 provided in the above-described vehicle 2. Fig. 3 is a block diagram showing the configuration of the vehicle control device 1 according to this embodiment.

[0023] As shown in FIG. 3, the vehicle control ECU (electronic control unit) 10 is an electronic control unit that controls the entire vehicle control device 1. It includes a CPU 31, which functions as a calculation device and a control device; a RAM 32, which is used as a working memory when the CPU 31 performs various calculation processes and stores displacements and integrated values ​​of wheel speed pulses input from the wheel speed sensors 8A-8D; a ROM 33, which stores control programs as well as a vehicle information detection processing program (see FIG. 4), which will be described later; and a flash memory 34, which stores programs read from the ROM 33. The vehicle control ECU 10 also includes various means for processing algorithms. For example, a wheel speed pulse acquisition means acquires wheel speed pulses, separated by the number of wheels on the vehicle, output in accordance with the rotation of each wheel. A vehicle speed detection means calculates the vehicle speed based on the wheel speed pulses acquired by the wheel speed pulse acquisition means. The vehicle behavior determination means determines whether the vehicle is in a stopped state or a moving state based on the vehicle speed calculated by the vehicle speed detection means and the wheel speed pulses acquired by the wheel speed pulse acquisition means. The erroneous detection determination means turns on an erroneous detection determination flag indicating that wheel speed pulses have been erroneously acquired from the specific wheel when wheel speed pulses are acquired consecutively only from the specific wheel while wheel speed pulses are not acquired from wheels other than some specific wheels among the multiple wheels equipped on the vehicle, and when the acquisition of the consecutive wheel speed pulses has occurred more than a first time since the last acquisition of wheel speed pulses from the wheels other than the specific wheel.

[0024] Furthermore, in addition to the above-mentioned wheel speed sensors 8A to 8D, the vehicle control ECU 10 is also connected to various sensors 36, such as a distance measurement sensor, an acceleration sensor, a gyro sensor, a steering sensor, and a shift position sensor, for detecting the surrounding conditions and the behavior of the vehicle, as well as to each drive unit 37 of the vehicle, such as the steering, brake, accelerator, and transmission, and is able to perform various driving assistance for the vehicle 2 by controlling each drive unit 37 while detecting the surrounding conditions and the current behavior of the vehicle based on the detection results of these sensors 36. Also, a camera or the like may be provided as means for detecting the surroundings of the vehicle.

[0025] The flash memory 34 also includes a vehicle information DB 35, which stores various information related to the vehicle 2. For example, the vehicle information DB 35 stores the installation positions (height from the ground and left-right position) of the cameras and sensors installed in the vehicle 2, the detection axes (optical axes for cameras), overall length, vehicle width, wheelbase, minimum turning radius, etc. This information is input in advance by the occupants or a person from the vehicle manufacturer.

[0026] Next, a vehicle information detection processing program executed by the vehicle control ECU 10 in the vehicle control device 1 having the above configuration will be described with reference to Fig. 4. Fig. 4 is a flowchart of the vehicle information detection processing program according to this embodiment. Here, the vehicle information processing program is executed after the ACC power supply (accessory power supply) of the vehicle 2 is turned on, and is a program that detects the vehicle speed and determines the vehicle running state based on wheel speed pulses input from each of the wheel speed sensors 8A to 8D. The program shown in the flowchart in Fig. 4 below is stored in the RAM 32 and ROM 33 provided in the vehicle control device 1, and is executed by the CPU 31.

[0027] First, in step (hereinafter abbreviated as S) 1, the CPU 31 calculates the average value (hereinafter referred to as the average wheel speed) of the most recent wheel speed of the left rear wheel 3C calculated based on the wheel speed pulses input from the wheel speed sensor 8C and the most recent wheel speed of the right rear wheel 3D calculated based on the wheel speed pulses input from the wheel speed sensor 8D. The wheel speed of the left rear wheel 3C is calculated based on the time interval (the time between pulses) of the wheel speed pulses input from the wheel speed sensor 8C, and the wheel speed of the right rear wheel 3D is calculated based on the time interval of the wheel speed pulses input from the wheel speed sensor 8D, and the calculation cycle is set to, for example, 224 ms (milliseconds).

[0028] Meanwhile, in S2, which is performed in parallel with S1, the CPU 31 calculates the vehicle speed based on the integrated value (pulse count history) of the wheel speed pulses input from the wheel speed sensors 8A to 8D. The vehicle speed calculated in S2 is hereinafter referred to as the pulse count vehicle speed.

[0029] Specifically, only when it is determined that the pulse count vehicle speed calculation conditions are met, the vehicle movement amount is calculated from the integrated value of the wheel speed pulses of the left and right rear wheels to be calculated, and the pulse count vehicle speed is further calculated from the vehicle movement amount per unit time. The pulse count vehicle speed calculation cycle is, for example, 224 ms. The pulse count vehicle speed calculation conditions are that a pulse change, i.e., a pulse count, occurs within a fixed time period for each of the wheels 6A-6D, and the sum of the pulse count values ​​for the left and right rear wheels within the fixed time period is equal to or greater than a threshold value (e.g., three pulses, which is the minimum number of pulses required to calculate vehicle speed). On the other hand, if the pulse count vehicle speed calculation conditions are not met, the pulse count vehicle speed is set to "0."

[0030] The predetermined time (third time) that serves as a calculation condition for the pulse count vehicle speed is, for example, 1 second. This predetermined time is set so that the vehicle speed can be calculated even when traveling at the lower limit speed of 0.1 km / h. While this time varies depending on the wheel diameter, the predetermined time is set assuming a typical vehicle with a pulse interval of 864 ms when traveling at 0.1 km / h. If the predetermined time is set shorter than 864 ms, a vehicle traveling at 0.1 km / h may not satisfy the calculation condition (i.e., vehicle speed = 0). Therefore, it is desirable to set the predetermined time longer than 864 ms. On the other hand, if the predetermined time is set too long, it will take longer to calculate the pulse count vehicle speed immediately after the vehicle starts traveling, resulting in a delay in determining that the vehicle has transitioned from a stopped state to a traveling state. Therefore, in this embodiment, the predetermined time is set to 1 second, which is longer than 864 ms but not too long.

[0031] Even when the vehicle is stopped, if the electrodes of wheel speed sensors 8A-8D are located near the boundary between the bumps and grooves of rotors 7A-7D, slight wheel movement, such as when steering wheel 4 is turned or the vehicle body vibrates, may cause wheel speed pulses to be output. Such wheel speed pulses are generally detected only at specific wheels that meet certain conditions, and it is generally not possible for all wheels to detect them at approximately the same time. Therefore, in S2, pulse detection is required for all four wheels within a pulse interval corresponding to the minimum vehicle speed (0.1 km / h) to be detected, thereby confirming that there is no false detection as described above. By checking a total of three pulses from the left and right rear wheels, a reliable start can be detected in a short time.

[0032] Thereafter, in S3, the CPU 31 performs a vehicle speed switching process. In the vehicle speed switching process, if neither the most recent wheel speed of the left rear wheel 3C calculated based on the wheel speed pulses input from the wheel speed sensor 8C nor the most recent wheel speed of the right rear wheel 3D calculated based on the wheel speed pulses input from the wheel speed sensor 8D is "0," i.e., if it is estimated that the vehicle is traveling normally, the average wheel speed calculated in S1 is adopted as the vehicle speed. The wheel speed of the left rear wheel 3C is calculated based on the time interval between wheel speed pulses input from the wheel speed sensor 8C, and the wheel speed of the right rear wheel 3D is calculated based on the time interval between wheel speed pulses input from the wheel speed sensor 8D. The calculation cycle for these calculations is, for example, 224 ms. Therefore, the calculation cycle for the vehicle speed in S3 is also set to 224 ms.

[0033] On the other hand, if at least one of the most recent wheel speed of the left rear wheel 3C calculated based on the wheel speed pulses input from the wheel speed sensor 8C and the most recent wheel speed of the right rear wheel 3D calculated based on the wheel speed pulses input from the wheel speed sensor 8D is "0", that is, in a situation where it is difficult to accurately detect the vehicle speed from the wheel speed alone, such as when the vehicle is stopped, just before stopping, or just after starting, the pulse count vehicle speed calculated in S2 is used as the vehicle speed.

[0034] Thereafter, in S4, the CPU 31 performs a change amount guard process to suppress the change amount per unit time of the vehicle speed calculated in S3 to a threshold value or less so that the change in acceleration does not become too large.

[0035] Furthermore, in S5, the CPU 31 performs a filter process to correct inappropriate values ​​caused by noise, etc., for the vehicle speed after the amount of change has been suppressed in S4, and smooth the change in the vehicle speed. The vehicle speed (body speed) is finally calculated by the processes in S1 to S5.

[0036] Meanwhile, in S6, the CPU 31 calculates the amount of change in the wheel speed pulse for each of the wheels 6A to 6D based on the integrated value (pulse count history) of the wheel speed pulses input from the wheel speed sensors 8A to 8D. The calculated amount of change in the wheel speed pulse is used to integrate the amount of movement of the vehicle, and is also used in determining whether the vehicle is starting or stopping (S7), which will be described later.

[0037] However, when calculating the change in wheel speed pulse in S6 above, if wheel speed pulses are continuously input only from a specific wheel among the four wheels of the vehicle without wheel speed pulses being input from the specific wheel, and if 224 ms (first time) or more has passed since the last wheel speed pulse was acquired from a wheel other than the specific wheel when the continuous wheel speed pulses were acquired, an "erroneous detection determination flag" indicating that wheel speed pulses have been erroneously acquired from the specific wheel is turned ON. When the "erroneous detection determination flag" is turned ON, it is assumed that no wheel speed pulses have been acquired from the specific wheel (i.e., the change in wheel speed pulses from the specific wheel is "0"). Here, 224 ms, which is the condition for turning ON the "erroneous detection determination flag," corresponds to the vehicle speed calculation period (the time interval for detecting wheel speed pulse acquisition in order to calculate vehicle speed).

[0038] The erroneous detection determination flag that was set ON in S6 remains ON until it is determined in S7 that the vehicle has stopped. The erroneous detection determination flag is stored in the flash memory 34 or the like, and is initially set to OFF.

[0039] The specific wheel may be any of the wheels 6A to 6D, or may be only one of the wheels 6A to 6D (for example, the right rear wheel), or may be two or three wheels.

[0040] As mentioned above, even when the vehicle is stopped, if the electrodes of wheel speed sensors 8A-8D are located near the boundary between the bumps and grooves of rotors 7A-7D, slight wheel movement, such as steering wheel 4 or vehicle body vibration, may cause wheel speed pulses to be output. For example, the example shown in Figure 5 illustrates the changes in wheel speed pulses input from the four wheels when the vehicle is moving and stopped. In Figure 5, wheel speed pulses are continuously input from only the right rear wheel 3D, even though the vehicle is stopped and no wheel speed pulses are input from the other wheels. If a single pulse is input or if a pulse from another wheel is input shortly after it, this may be a normal detection before or after the vehicle stops or starts moving. However, if a continuous pulse is input more than 224 ms after the last wheel speed pulse from another wheel, it is determined to be an erroneous detection, and the erroneous detection flag is set to ON. Therefore, subsequent wheel speed pulses from the right rear wheel 3D are considered not to have been input.

[0041] To determine whether the error detection flag is set, the CPU 31 always counts the elapsed time since the most recent wheel speed pulse (change in pulse amount) was input, as shown in FIG. 6. When a new wheel speed pulse is input, if it is from a different wheel than the most recent one, the CPU 31 temporarily stops counting, stores the current count value t1, and starts a new count. On the other hand, if it is from the same wheel as the most recent one, the CPU 31 continues counting. As shown in FIG. 7, if wheel speed pulses are continuously input from the same wheel and the elapsed time since the most recent wheel speed pulse (change in pulse amount) was input from another wheel (corresponding to the sum of the most recent stored count value t1 and the current count value t2) is 224 ms or longer, the error detection flag is set to ON. Any subsequent wheel speed pulses from the target wheel (the rear left wheel in FIG. 7) are considered not to have been input. Wheel speed pulses considered not to have been input are not included in the calculation of the vehicle movement amount.

[0042] Furthermore, when the erroneous detection determination flag is turned ON, it is assumed that subsequent wheel speed pulses from the corresponding wheel (the wheel from which wheel speed pulses have been continuously input) have not been input, and in addition, the vehicle speed is forcibly set to 0 at a predetermined deceleration rate, as shown in Figure 7. In other words, when the erroneous detection determination flag is ON, the vehicle speed is calculated as 0 regardless of the wheel speed pulses acquired from the corresponding wheel.

[0043] Thereafter, in S7, the CPU 31 determines whether the vehicle is in a stopped state or a running state based on the wheel speed pulse change amount for each wheel calculated in S6 and the vehicle speed of the vehicle calculated in S1 to S5. Specifically, the determination is made under the following conditions: "Starting conditions (conditions for switching from stopped state to running state)" ·Vehicle speed>0 "Stop conditions (conditions for switching from running to stopped state)" Vehicle speed = 0 and the wheel speed pulse change of all four wheels is 0 and continues for 324 ms (second time) or more

[0044] Whether the vehicle is currently in a stopped state or a running state is specified by a vehicle stop flag stored in the flash memory 34 or the like. If the vehicle stop flag is ON, it indicates that the vehicle is currently in a stopped state, and if the vehicle stop flag is OFF, it indicates that the vehicle is currently in a running state. Therefore, in S6, if the stop condition is satisfied while the vehicle stop flag is OFF, the vehicle stop flag is switched from OFF to ON. On the other hand, if the start condition is satisfied while the vehicle stop flag is ON, the vehicle stop flag is switched from ON to OFF. Otherwise, the current vehicle stop flag is maintained. That is, if the vehicle is in a running state, the determination that the vehicle is in a running state is maintained, and if the vehicle is in a stopped state, the determination that the vehicle is in a stopped state is maintained.

[0045] The determination result of S7 as to whether the vehicle is stopped or moving is used, for example, for brake fluid pressure increase control or brake fluid pressure decrease control. When performing automatic driving assistance in a vehicle, the determination result as to whether the vehicle is stopped or moving can be reflected in the control of the automatic driving assistance to enable more appropriate control. The above is just one example, and the determination result as to whether the vehicle is stopped or moving can be used for various other driving assistance and vehicle control.

[0046] In this embodiment, the determination of the stopped state and the running state is performed by the vehicle information detection processing program described above, thereby enabling a quicker and more accurate determination than in the past.

[0047] For example, first, let us use Figure 8 to explain the case where a vehicle stops from a running state. As described above, when the vehicle is in a running state, if the "stop condition" of vehicle speed = 0 and the change amount of wheel speed pulses of all four wheels is 0 and continues for 324 ms or more, it is determined that the vehicle has transitioned from a running state to a stopped state. Here, as described in S6 above, if the erroneous detection determination flag is turned ON, it is assumed that no wheel speed pulses are subsequently input from the target wheel (the rear left wheel in Figure 8). Therefore, by identifying in advance when a wheel speed pulse may be erroneously acquired as shown in Figure 8 using the erroneous detection determination flag, it is no longer necessary to determine whether the vehicle is truly stopped by setting a long determination time after the vehicle speed reaches 0, as in the past. Specifically, it is possible to determine whether the vehicle is stopped in as little as 324 ms after the vehicle speed reaches 0, which is an extremely short determination time compared to the past.

[0048] For example, in the case where the erroneous detection determination flag is turned ON and the vehicle speed is forcibly set to 0 as shown in Fig. 8, if 324 ms elapses thereafter while the vehicle speed remains at 0 and no wheel speed pulses are acquired from wheels other than the wheel that caused the erroneous detection determination flag to be turned ON (the wheel with continuous pulses), the vehicle will transition from a running state to a stopped state. Note that the erroneous detection determination flag is turned OFF after it is determined that the vehicle has transitioned to a stopped state.

[0049] If the vehicle speed becomes 0 without the false detection judgment flag being turned ON (for example, if the calculation condition for the pulse count vehicle speed in S2 is no longer met), and if 324 ms elapses with the vehicle speed remaining at 0 and no wheel speed pulse is acquired from any of the wheels during that time, the vehicle will transition from a running state to a stopped state.

[0050] Next, referring to Figure 9, the case where the vehicle starts moving from a stopped state will be explained. As mentioned above, the calculation condition for pulse count vehicle speed in S2 is that pulse counts are input from all four wheels within 1 second, so even if a wheel speed pulse is input from only the right rear wheel 3D as shown in Figure 9, it will be considered an erroneous detection and pulse count vehicle speed = 0. Since the calculated wheel speeds of the left and right rear wheels are also 0 when only one pulse is input, vehicle speed = 0 is calculated in S3, and since the "start condition" in S7 is not met, the vehicle stop flag remains ON. In other words, it is determined that the vehicle is stopped.

[0051] On the other hand, in this embodiment, when pulse counts are input from all four wheels within 1 second and the sum of the pulse count values ​​from the left rear wheel and the right rear wheel reaches 3 pulses or more, the calculation condition for the pulse count vehicle speed is met, and the pulse count vehicle speed > 0. Even if the wheel speed of at least one of the left and right rear wheels is calculated to be 0, the pulse count vehicle speed is used in S3, so the vehicle speed > 0. Therefore, the "start condition" of S7 is met, and the vehicle stop flag changes from ON to OFF, meaning that the vehicle is determined to be in a running state (has started running). As a result, it is possible to reduce the time lag between when the vehicle actually starts running and when it is determined to be in a running state, compared to conventional methods.

[0052] In the prior art, the calculation condition for pulse count vehicle speed was, for example, that the sum of the pulse count values ​​for the left and right rear wheels be 5 or more pulses. This resulted in a longer time lag between when the vehicle actually started moving and when it was determined that the vehicle was moving, compared to the present embodiment. Furthermore, in the prior art, the calculation condition for pulse count vehicle speed did not include pulse count input from all four wheels. For example, as shown in FIG. 5, if pulses were input continuously from only one rear wheel, the vehicle speed could be erroneously determined to be greater than 0, thereby satisfying the "start condition." In the present embodiment, the calculation condition for pulse count vehicle speed includes pulse count input from all four wheels. Therefore, even if the condition for the sum of the pulse count values ​​for the left and right rear wheels is relaxed from 5 or more pulses to 3 or more pulses (the minimum requirement for vehicle speed calculation), the erroneous detection of a vehicle starting to move when the vehicle is stopped, as in the prior art, can be prevented.

[0053] As explained in detail above, the vehicle control device 1 and the computer program executed by the vehicle control device 1 according to this embodiment acquire wheel speed pulses output in accordance with the rotation of each of the plurality of wheels provided on the vehicle, calculate the vehicle speed based on the acquired wheel speed pulses (S1 to S5), and determine whether the vehicle is in a stopped state or a moving state based on the calculated vehicle speed and wheel speed pulses (S6, S7). On the other hand, when wheel speed pulses are acquired consecutively only from a specific wheel among the plurality of wheels provided on the vehicle while wheel speed pulses are not acquired from wheels other than some specific wheels, and If two consecutive wheel speed pulses have been acquired more than a first time since the last acquisition of a wheel speed pulse from a wheel other than the specific wheel, an erroneous detection determination flag is turned on, indicating that a wheel speed pulse has been erroneously acquired from the specific wheel, and while the erroneous detection determination flag is on, it is assumed that a wheel speed pulse has not been acquired from the specific wheel and a determination is made as to whether the vehicle is stopped or running (S7).By identifying in advance a state in which a wheel speed pulse may be erroneously acquired using the erroneous detection determination flag, it is no longer necessary to determine whether the vehicle is stopped or running after a certain period of time, as in the past.As a result, when determining whether the vehicle is stopped or running using the wheel speed pulse, it is possible to make the determination more quickly and accurately than in the past. Furthermore, since the first time is the time interval for calculating the vehicle speed, it is possible to prevent the erroneous detection determination flag from being erroneously set to on, i.e., to prevent a normal wheel speed pulse from being considered as not having been acquired even though it has been acquired. Furthermore, when the erroneous detection judgment flag is on, the vehicle speed is calculated as 0 regardless of the wheel speed pulse obtained from the specific wheel, and if the vehicle is determined to be in a running state and the vehicle speed remains at 0 for a second time period, and no wheel speed pulses are obtained from wheels other than the specific wheel during that time, it is determined that the vehicle has transitioned from a running state to a stopped state, and after it is determined that the vehicle has transitioned to a stopped state, the erroneous detection judgment flag is turned off.Therefore, even when there is erroneous detection of the wheel speed pulse, it is possible to reduce the time lag between when the vehicle actually stops and when it is determined that the vehicle is in a stopped state, compared to conventional methods. Furthermore, after the conditions are met that wheel speed pulses are acquired from multiple wheels of the vehicle within three hours while the vehicle speed is 0, and a predetermined number or more of wheel speed pulses are acquired from the rear wheels within the same three hours, calculation of the vehicle speed begins, and if a vehicle speed greater than 0 is calculated while the vehicle is determined to be in a stopped state, it is determined that the vehicle has transitioned from a stopped state to a running state (S7).This makes it possible to reduce the time lag between when the vehicle actually starts running and when it is determined that the vehicle is in a running state, compared to conventional methods.

[0054] The present invention is not limited to the above-described embodiment, and it goes without saying that various improvements and modifications are possible within the scope of the present invention. For example, in this embodiment, the first time period is 224 ms, the second time period is 324 ms, and the third time period is 864 ms, but these times can be changed as appropriate. However, it is desirable that the first time period be equivalent to the calculation cycle of the vehicle speed, the second time period be as short as possible within a range longer than the first time period, and the third time period be as short as possible within a range longer than the pulse interval (e.g., 864 ms) when traveling at 0.1 km / h.

[0055] In addition, in this embodiment, the vehicle information detection processing program (FIG. 4) is configured to be executed by the vehicle control ECU 10 of the vehicle control device 1, but the executing entity can be changed as appropriate. For example, the processing may be executed by a control unit that performs automatic driving assistance or other in-vehicle device. [Explanation of symbols]

[0056] 1... vehicle control device, 2... vehicle, 8A to 8D... wheel speed sensors, 10... vehicle control ECU, 31... CPU

Claims

1. a wheel speed pulse acquiring means for acquiring wheel speed pulses outputted in association with the rotation of each of the plurality of wheels of the vehicle; a vehicle speed detection means for calculating a vehicle speed of the vehicle based on the wheel speed pulses acquired by the wheel speed pulse acquisition means; a vehicle behavior determination means for determining whether the vehicle is in a stopped state or a moving state based on the vehicle speed calculated by the vehicle speed detection means and the wheel speed pulses acquired by the wheel speed pulse acquisition means; and an erroneous detection determination means for turning on an erroneous detection determination flag indicating that wheel speed pulses have been erroneously acquired from a specific wheel when wheel speed pulses are acquired consecutively only from a specific wheel among a plurality of wheels provided on a vehicle while wheel speed pulses are not acquired from the wheels other than the specific wheel and when the acquisition of consecutive wheel speed pulses has occurred more than a first time since the last acquisition of wheel speed pulses from the wheels other than the specific wheel, The vehicle behavior determination means determines whether the vehicle is in the stopped state or the running state by assuming that a wheel speed pulse has not been acquired from the specific wheel when the erroneous detection determination flag is on.

2. 2. The vehicle control device according to claim 1, wherein the first time period is a time interval during which the vehicle speed detection means calculates the vehicle speed.

3. the vehicle speed detection means calculates the vehicle speed as 0 regardless of the wheel speed pulse acquired from the specific wheel when the erroneous detection determination flag is on, the vehicle behavior determination means determines that the vehicle has transitioned from a running state to a stopped state when a second time period has elapsed since the vehicle speed detection means calculated the vehicle speed to be 0 while the vehicle speed was 0, and no wheel speed pulses have been acquired from wheels other than the specific wheel during that time period; 3. The vehicle control device according to claim 1, wherein the erroneous detection determination flag is turned off after it is determined that the vehicle has transitioned to the stopped state.

4. the vehicle speed detection means starts calculating the vehicle speed after satisfying a condition that wheel speed pulses are acquired from a plurality of wheels provided on the vehicle within a third hour while the vehicle speed is zero, and a predetermined number or more of wheel speed pulses are acquired from the rear wheels within the same third hour; 3. The vehicle control device according to claim 1, wherein the vehicle behavior determination means determines that the vehicle has transitioned from a stopped state to a running state when the vehicle speed detection means calculates a vehicle speed greater than 0 while the vehicle is determined to be in a stopped state.

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