Vehicle control device, vehicle control method, and control program

Abstract

The present invention provides a vehicle control device that can activate safety devices based on an appropriate vehicle speed. [Solution] The vehicle control device 1 includes an obstacle recognition unit 41 that recognizes obstacles around the vehicle 2 based on signals from a radar 11, a vehicle speed calculation unit 44 that calculates the vehicle speed based on multiple wheel speeds detected by multiple wheel speed sensors 16A to 16D provided on multiple wheels 20A to 20D, and a safety device control unit that controls safety devices based on the position of obstacles and the vehicle speed. The vehicle speed calculation unit 44 selects from multiple wheel speeds to be used to calculate the vehicle speed based on the state of the vehicle 2.

Description

Technical Field

[0005]

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

Background Art

[0002] In recent years, efforts have been actively made to provide a sustainable transportation system that takes into account people in vulnerable positions among traffic participants. In order to further improve traffic safety and convenience towards this realization, research and development on safety technologies have been carried out.

[0003] The control content of a safety device such as an airbag provided in a vehicle may be changed based on the vehicle speed. For example, Patent Document 1 discloses a vehicle control device that deploys an airbag when the acceleration becomes equal to or higher than a deployment threshold value. The vehicle control device predicts the possibility of a collision with an obstacle based on the vehicle speed, and reduces the deployment threshold value of the airbag based on the possibility of the collision. As a result, when there is a possibility of a collision, the airbag is deployed at a smaller acceleration.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when an error occurs in the vehicle speed, it becomes difficult to appropriately control the safety device. For example, when calculating the vehicle speed based on a signal from a wheel speed sensor provided on a wheel, there is a problem that an error occurs in the vehicle speed due to wheel slip. Further, when the wheel speed sensor is composed of a permanent magnet and a Hall element, there is a possibility that the wheel speed sensor outputs an incorrect value due to the influence of electromagnetic waves generated during charging.

[0006] In view of the above background, one aspect of the present invention aims to provide a vehicle control device, a vehicle control method, and a control program that can activate a safety device based on an appropriate vehicle speed. [Means for solving the problem]

[0007] To solve the above problems, one aspect of the present invention provides a vehicle control device comprising: an obstacle recognition unit that recognizes obstacles around the vehicle based on signals from radar; a vehicle speed calculation unit that calculates the vehicle speed based on a plurality of wheel speeds detected by a plurality of wheel speed sensors provided on a plurality of wheels; and a safety device control unit that controls a safety device based on the position of the obstacle and the vehicle speed, wherein the vehicle speed calculation unit selects the wheel speed to be used to calculate the vehicle speed from among a plurality of wheel speeds based on the state of the vehicle.

[0008] Another aspect of the present invention is a vehicle control method performed by a computer, which recognizes obstacles around the vehicle based on signals from radar, calculates the vehicle speed based on a plurality of wheel speeds detected by a plurality of wheel speed sensors provided on a plurality of wheels, controls safety devices based on the position of the obstacles and the vehicle speed, and selects from the plurality of wheel speeds to be used to calculate the vehicle speed based on the state of the vehicle.

[0009] Another aspect of the present invention is a control program for causing a computer to execute a vehicle control method, which causes the computer to recognize obstacles around the vehicle based on signals from radar, calculate the vehicle speed based on a plurality of wheel speeds detected by a plurality of wheel speed sensors provided on a plurality of wheels, control a safety device based on the position of the obstacles and the vehicle speed, and select the wheel speed to be used to calculate the vehicle speed from among the plurality of wheel speeds based on the state of the vehicle. [Effects of the Invention]

[0010] According to the above embodiments, it is possible to provide a vehicle control device, a vehicle control method, and a control program that can activate a safety device based on an appropriate vehicle speed. [Brief explanation of the drawing]

[0011] [Figure 1] Configuration diagram of a vehicle control device according to this embodiment [Figure 2] Explanatory diagram of a vehicle according to an embodiment [Figure 3] Flowchart showing the vehicle speed calculation procedure in the vehicle control method according to the embodiment. [Figure 4] Flowchart showing the procedure for setting the deployment threshold in the vehicle control method according to the embodiment. [Figure 5] Flowchart showing the airbag deployment control procedure in the vehicle control method according to the embodiment. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the vehicle control device, vehicle control method, and control program will be described with reference to the drawings.

[0013] As shown in Figures 1 and 2, the vehicle control device 1 is installed in the vehicle 2. The vehicle 2 is a four-wheeled automobile. The vehicle 2 may be an autonomous vehicle or a vehicle with driver assistance functions.

[0014] Vehicle 2 has a propulsion system 3, a braking system 4, and a steering system 5. The propulsion system 3 is a device that provides driving force to vehicle 2 and includes, for example, a power source and a transmission. The power source has at least one of an internal combustion engine such as a gasoline engine or a diesel engine and an electric motor. The braking system 4 is a device that provides braking force to vehicle 2 and includes, for example, a brake caliper that presses pads against a brake rotor and an electric cylinder that supplies hydraulic pressure to the brake caliper. The steering system 5 is a device for changing the steering angle of the wheels and includes, for example, a rack and pinion mechanism that steers the wheels and an electric motor that drives the rack and pinion mechanism. The propulsion system 3, the braking system 4, and the steering system 5 are controlled by a vehicle control device 1.

[0015] Vehicle 2 has an external environment recognition device 7. The external environment recognition device 7 is a device that detects objects outside the vehicle. The external environment recognition device 7 is a sensor that detects objects outside the vehicle by capturing electromagnetic waves and light from the surroundings of Vehicle 2. The external environment recognition device 7 includes a radar 11, a LiDAR 12, and a camera 13.

[0016] Radar 11 detects the position and speed of an object by transmitting radio waves around the vehicle 2 and receiving radio waves reflected by the object. Radar 11 may be a millimeter-wave radar that utilizes millimeter waves for electromagnetic radiation. Multiple radars 11 may be installed on the vehicle 2. Radar 11 includes at least a forward radar that detects objects in the area in front of the vehicle 2. Radar 11 may also include a rear radar that detects obstacles in the area behind the vehicle 2. Radar 11 may also include a plurality of corner radars that detect obstacles in the areas to the right front, left front, right rear, and left rear of the vehicle 2.

[0017] One of the radars 11, the forward radar, is preferably located in the center of the front end of the vehicle 2 in the left-right direction and transmits radio waves forward. The forward radar may be located, for example, behind an emblem located on the front end of the vehicle 2. The emblem may be made of a resin material that transmits radio waves. The forward radar transmits radio waves to the left and right at a predetermined angular width with respect to a center line extending forward from the vehicle 2. The angular width may be set, for example, to 20° to the left and 15° to the right. For example, the forward radar may transmit radio waves within a range of 30m to the left and right at a distance of 150m ahead. The forward radar may also transmit radio waves vertically at a predetermined angular width with respect to the center line.

[0018] Radar 11 transmits radio waves in pulses and measures the time it takes for the reflected waves, which have been reflected by an object, to return. Radar 11 also detects the intensity of the reflected waves and uses the directivity of its antenna to detect the angle at which the object is located. Furthermore, Radar 11 uses the Doppler effect to measure the velocity of the object based on the difference between the frequency of the reflected waves and the frequency of the transmitted waves. Radar 11 outputs radar data containing this information.

[0019] The lidar 12 irradiates light such as infrared light around the vehicle 2 and captures the reflected light to detect the position (distance and direction) of an object. The lidar 12 may detect obstacles existing in the area in front of the vehicle 2.

[0020] The camera 13 images the surroundings of the vehicle 2 and acquires an image of the surroundings of the vehicle 2. The image of the surroundings of the vehicle 2 includes surrounding vehicles (surrounding moving objects), pedestrians, guardrails, curbs, walls, median strips, road shapes, lane lines, road signs drawn on the road, etc. existing around the vehicle 2. The camera 13 may be, for example, a digital camera using a solid-state imaging device such as a CCD or a CMOS. The camera 13 includes a front camera that images at least the area in front of the vehicle 2. The camera 13 may include a rear camera that images the rear of the vehicle 2 and a pair of side cameras that image the left and right sides of the vehicle 2. The camera 13 may be, for example, a stereo camera.

[0021] The vehicle 2 has a vehicle sensor 15. The vehicle sensor 15 includes a vehicle speed sensor 16 that detects the speed of the vehicle 2, an acceleration sensor 17 that detects acceleration, and a yaw rate sensor 18 that detects the angular velocity around the vertical axis. The vehicle sensor 15 may include an azimuth sensor or the like that detects the orientation of the vehicle 2.

[0022] The vehicle speed sensor 16 includes four wheel speed sensors 16A to 16D provided on the four wheels 20A to 20D. Each of the wheel speed sensors 16A to 16D detects the rotational speed of the corresponding wheel 20A to 20D. The wheel speed sensors 16A to 16D may be, for example, magnetic rotary encoders constituted by a hall element and a permanent magnet. In the present embodiment, the left and right front wheels are drive wheels 20A and 20B driven by the propulsion device 3, and the left and right rear wheels are driven wheels 20C and 20D. The four wheel speed sensors 16A to 16D are provided on each of the left and right drive wheels 20A and 20B and the left and right driven wheels 20C and 20D.

[0023] The acceleration sensor 17 may detect the acceleration of the vehicle 2 in the longitudinal direction and the vertical direction. The acceleration sensor 17 may also detect the acceleration of the vehicle 2 in the lateral direction.

[0024] Vehicle 2 is equipped with a GNSS (Global Navigation Satellite System) receiver 22. The GNSS receiver 22 determines the position (latitude and longitude) of vehicle 2 based on signals received from artificial satellites (positioning satellites).

[0025] Vehicle 2 is equipped with an HMI23 (Human Machine Interface). The HMI23 provides various information to the occupants through displays and voice prompts, and also accepts input operations from the occupants. The HMI23 may include, for example, a touch panel display and speakers.

[0026] Vehicle 2 is equipped with an airbag unit 24 to protect occupants in the event of a collision. The airbag unit 24 comprises an airbag 24A and an inflator 24B that inflates the airbag 24A. The inflator 24B receives an electrical signal from the vehicle control device 1, generates expansion gas, and inflates the airbag 24A. The airbag unit 24 may be installed in the steering wheel, instrument panel, front pillar, middle pillar, rear pillar of vehicle 2, or on the side of the seat back of the seats. The airbag 24A is a type of safety device.

[0027] Vehicle 2 is equipped with a battery 25. The battery 25 supplies power to the propulsion system 3. The battery 25 can be connected to an external power source via a charging port 26 provided on vehicle 2. The battery 25 receives power from the external power source and is charged.

[0028] The vehicle control device 1 is a computer having a processor 31 and a memory 32 that is communicatively connected to the processor 31. The processor 31 may include at least one of the following as its core: a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a RISC (Reduced Instruction Set Computer). The memory 32 stores control programs executed by the processor 31 and various data. The memory 32 may include at least one of volatile memory and non-volatile memory. The volatile memory may be, for example, DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory). The non-volatile memory may be an SSD (Solid State Drive), flash memory, magnetic disk storage device, or optical disk storage device. At least a part of the vehicle control device 1 may be implemented by hardware such as an LSI (Large Scale Integration), ASIC (application specific integrated circuit), or FPGA (field-programmable gate array), or by a combination of software and hardware. The vehicle control device 1 may be composed of a single piece of hardware, or it may be composed of multiple pieces of hardware that can communicate with each other. Part of the vehicle control device 1 may be composed of an external server located outside the vehicle 2.

[0029] The processor 31 implements various applications by executing programs stored in memory 32. Programs may be stored on removable recordable media such as DVDs or CD-ROMs, and installed in memory 32 when the recordable media is read by a reader. Alternatively, programs may be downloaded to and installed in memory 32 via a communication network such as the internet.

[0030] The memory 32 should preferably store map information. The map information should preferably be high-resolution map information. The map information should include road information such as the type of road (expressway, toll road, national road, prefectural road), the number of lanes on the road, the center position of each lane (3D coordinates including longitude, latitude, and height), the shape of road markings such as road markings and lane boundaries, the presence or absence of sidewalks, curbs, fences, etc., the location of intersections, the locations of lane merging and branching points, the area of ​​emergency parking zones, the width of each lane, and road signs. In addition, the map information may also include traffic regulation information, address information (address and postal code), facility information, telephone number information, etc.

[0031] The processor 31 functions as an obstacle recognition unit 41, a vehicle position recognition unit 42, an acceleration detection unit 43, a vehicle speed calculation unit 44, a driving control unit 45, a proximity collision prediction unit 46, an airbag control unit 47, a notification unit 48, and a charging control unit 49 by executing a program stored in the memory 32.

[0032] The obstacle recognition unit 41 recognizes the surrounding environment of the vehicle 2. Based on the detection results of the external environment recognition device 7, the obstacle recognition unit 41 recognizes the surrounding environment (external world), including obstacles located around the vehicle 2, the shape of the road, the presence or absence of sidewalks, road markings, etc. Obstacles include, for example, guardrails, utility poles, surrounding vehicles, and people such as pedestrians. From the detection results of the external environment recognition device 7, the obstacle recognition unit 41 can acquire the status of surrounding vehicles, such as their position, speed, and acceleration.

[0033] In this embodiment, the obstacle recognition unit 41 recognizes obstacles around the vehicle 2 based on signals from the radar 11. The obstacle recognition unit 41 acquires the position and speed of the obstacles based on the radar data. The position of the obstacle may be expressed as the distance between the vehicle 2 and the obstacle, and the angle of the obstacle relative to the vehicle 2. The obstacle recognition unit 41 may recognize targets whose reflected wave intensity is above a predetermined value as obstacles.

[0034] The vehicle position recognition unit 42 recognizes the position of vehicle 2. The vehicle position recognition unit 42 may recognize the position of vehicle 2 based on the GNSS signal received by the GNSS receiver 22.

[0035] The acceleration detection unit 43 detects the acceleration of the vehicle 2 based on the signal from the acceleration sensor 17. The acceleration detection unit 43 may include longitudinal acceleration, lateral acceleration, and vertical acceleration of the vehicle 2.

[0036] The vehicle speed calculation unit 44 calculates the vehicle speed based on multiple wheel speeds detected by multiple wheel speed sensors 16A to 16D provided on multiple wheels 20A to 20D. Based on the state of the vehicle 2, the vehicle speed calculation unit 44 selects from the multiple wheel speeds to be used to calculate the vehicle speed. The state of the vehicle 2 includes, for example, the operating state of the anti-lock braking system (hereinafter referred to as ABS), the operating state of the traction control system (hereinafter referred to as TCS), the state in which the yaw rate of the vehicle 2 is above a predetermined judgment value, the charging state, etc. The operating state of the ABS and the operating state of the TCS are obtained from the driving control unit 45.

[0037] The driving control unit 45 performs ABS control and TCS control. In ABS control, the driving control unit 45 acquires the wheel speed of each wheel 20A to 20D and reduces the braking force of wheels 20A to 20D whose wheel speed is below a predetermined lock threshold. This prevents wheels 20A to 20D from locking. The driving control unit 45 may also perform ABS control only on the drive wheels 20A and 20B.

[0038] In TCS control, the driving control unit 45 acquires the wheel speed of each wheel 20A to 20D, obtains the difference between the maximum and minimum values ​​of each wheel speed, and reduces the driving force of the propulsion device 3 if the difference is greater than or equal to a predetermined slip threshold. This prevents the drive wheels 20A and 20B from slipping.

[0039] The vehicle speed calculation unit 44 determines whether the ABS is activated and whether the TCS is activated based on the signal from the driving control unit 45. If the ABS is activated, the vehicle speed calculation unit 44 sets the average of the two highest wheel speeds among the four wheel speeds to the vehicle speed. If the TCS is activated, the vehicle speed calculation unit 44 sets the average of the wheel speeds of the two driven wheels 20C and 20D, or the average of the two lowest wheel speeds to the vehicle speed.

[0040] The vehicle speed calculation unit 44 sets the average of the four wheel speeds as the vehicle speed if the yaw rate of the vehicle 2 is greater than or equal to a predetermined threshold value. If the yaw rate is greater than or equal to the threshold value, it is estimated that the vehicle 2 is traveling on a curve. In this case, it is considered that there is a difference in rotational speed between the right wheels 20A to 20D and the left wheels 20A to 20D.

[0041] The approach collision prediction unit 46 determines the possibility of a collision between the obstacle and the vehicle 2. The approach collision prediction unit 46 determines that there is a possibility of a collision between the obstacle and the vehicle 2 if the time to collision (TTC) between the obstacle and the vehicle 2 is less than or equal to the collision threshold. The approach collision prediction unit 46 may determine the possibility of a collision for obstacles detected by the obstacle recognition unit 41 that are within a predetermined distance from the vehicle 2. The collision time may be calculated by dividing the distance between the obstacle and the vehicle 2 by the relative speed between the obstacle and the vehicle 2.

[0042] Furthermore, the approach collision prediction unit 46 determines that an obstacle is approaching the vehicle 2. The approach collision prediction unit 46 may determine that the obstacle is approaching the vehicle 2 based on the distance between the obstacle and the vehicle 2.

[0043] The airbag control unit 47 deploys the airbag 24A installed in the vehicle 2 when the acceleration is equal to or greater than the deployment threshold. When the acceleration is equal to or greater than the deployment threshold, the airbag control unit 47 transmits an electrical signal to the inflator 24B of the airbag unit 24. The inflator 24B receives the electrical signal from the airbag control unit 47, generates expansion gas, and inflates the airbag 24A. The acceleration may be the longitudinal acceleration, lateral acceleration, or vertical acceleration of the vehicle 2.

[0044] The airbag control unit 47 changes the deployment threshold based on the collision margin between the obstacle and the vehicle 2. Specifically, when the approach collision prediction unit 46 determines, based on the collision margin, that there is a possibility of collision between the obstacle and the vehicle 2, the airbag control unit 47 lowers the deployment threshold. By lowering the deployment threshold, the vehicle can exceed the deployment threshold at a smaller acceleration, and the airbag 24A will deploy earlier. As a safety device control unit, the airbag control unit 47 controls the safety device based on the position of the obstacle and the vehicle speed.

[0045] The notification unit 48 controls the HMI 23 to provide notification when an obstacle is approaching the vehicle 2. The HMI 23 controlled by the notification unit 48 may provide notification by image or sound. The notification provided by the HMI 23 may be so-called blind spot information (BSI), which notifies the occupant that another vehicle is present in the blind spot behind the vehicle. The blind spot information may be an image displayed in the side mirror or an image displayed on a display inside the vehicle. The HMI 23 that notifies the occupant of the presence of another vehicle can be said to be a type of safety device.

[0046] The charging control unit 49 controls the charging of the battery 25 when an external power supply is connected to the charging port 26. The charging control unit 49 detects the State of Charge (SOC) of the battery 25 and controls the power supplied to the battery 25 from the external power supply based on the SOC.

[0047] Next, the vehicle control method performed by the vehicle control device 1 will be described with reference to Figures 3 to 5. Figure 3 is a flowchart showing the procedure for determining the vehicle speed. First, the vehicle control device 1 determines whether or not the ABS is operating (ST1). If the ABS is operating (ST1: Yes), the vehicle control device 1 sets the vehicle speed to the average of the two highest wheel speeds among the four wheel speeds (ST2). In other embodiments, in step ST2, the vehicle control device 1 may set the wheel speed to the average of the two highest wheel speeds.

[0048] If ABS is not activated (ST1: No), the vehicle control device 1 determines whether or not TCS is activated (ST3). If TCS is activated (ST3: Yes), the vehicle control device 1 sets the average value of the wheel speeds of the two driven wheels 20C and 20D as the vehicle speed (ST4). In other embodiments, in step ST4, the vehicle control device 1 may set the average value of the two wheel speeds with lower values ​​as the wheel speed.

[0049] If the TCS is not operating (ST3: No), the vehicle control device 1 determines whether the yaw rate is equal to or greater than the judgment value (ST5). If the yaw rate is equal to or greater than the judgment value (ST5: Yes), the vehicle control device 1 sets the average of the four wheel speeds to the vehicle speed (ST6).

[0050] If the yaw rate is less than the judgment value (ST5: No), the vehicle control device 1 sets the average value of the two drive wheels 20A and 20B to the vehicle speed (ST7).

[0051] Figure 4 is a flowchart showing the procedure for setting the deployment threshold. The vehicle control device 1 repeatedly performs the procedure for setting the deployment threshold at predetermined time intervals. First, the vehicle control device 1 detects obstacles based on radar data acquired from the radar 11 (ST11). The number of obstacles detected may be zero or one or more.

[0052] Next, the vehicle control device 1 determines whether or not an obstacle exists (ST12). If an obstacle exists (ST12: Yes), the vehicle control device 1 calculates the collision margin time between each obstacle and the vehicle 2 (ST13). The collision margin time is preferably calculated by dividing the distance between the obstacle and the vehicle 2 by the relative speed between the obstacle and the vehicle 2. The relative speed between the obstacle and the vehicle 2 is preferably calculated based on the vehicle speed of the vehicle 2 set according to the procedure in Figure 3 and the speed of the obstacle acquired by the radar 11.

[0053] Next, the vehicle control device 1 determines whether the smallest value among the calculated collision margin times is less than or equal to the collision threshold (ST14).

[0054] If the collision margin time is less than or equal to the collision threshold (ST14: Yes), the vehicle control device 1 sets a reduction threshold for the deployment threshold (ST15).

[0055] If no obstacles are present (ST12: No), or if the collision margin time is greater than the collision threshold (ST14: No), the vehicle control device 1 sets an initial value for the deployment threshold (ST16).

[0056] Figure 5 is a flowchart showing the deployment control procedure for airbag 24A. The vehicle control device 1 repeats the airbag 24A deployment control procedure shown in Figure 5 at predetermined time intervals. The vehicle control device 1 determines whether the acceleration of the vehicle 2 acquired by the acceleration sensor 17 is equal to or greater than the deployment threshold (ST21). The acceleration of the vehicle 2 may be longitudinal acceleration, lateral acceleration, or vertical acceleration. The deployment threshold is set based on the deployment threshold setting procedure shown in Figure 3.

[0057] If the acceleration of vehicle 2 is greater than or equal to the deployment threshold (ST21: Yes), the vehicle control device 1 deploys the airbag 24A (ST22). Specifically, the vehicle control device 1 outputs an electrical signal to the inflator 24B of the airbag unit 24, causing the inflator 24B to generate expansion gas.

[0058] If the acceleration of vehicle 2 is below the deployment threshold (ST21: No), the process proceeds to return.

[0059] According to the above embodiment, the wheel speed used can be changed according to the state of the vehicle 2, and an appropriate vehicle speed can be calculated. As a result, a vehicle control device 1 can be provided that can activate the airbag 24A as a safety device based on the appropriate vehicle speed. In the vehicle control device 1, the deployment threshold of the airbag 24A is set based on the collision margin time, and the collision margin time is calculated based on the vehicle speed of the vehicle 2.

[0060] The vehicle speed of vehicle 2 is also used when determining the speed of obstacles such as surrounding vehicles detected by radar 11 using the Doppler effect. Therefore, accurately calculating the vehicle speed of vehicle 2 is important for controlling vehicle 2.

[0061] The embodiments are not limited to the above configuration and can be broadly modified. For example, when the vehicle 2 is charging, the vehicle speed calculation unit 44 may set the vehicle speed to the average of the three values ​​with the smallest difference from the median among the four wheel speed values. When the charging control unit 49 is performing charging control of the battery 25, it is preferable to output a signal to the vehicle speed calculation unit 44 indicating that charging is in progress. The vehicle speed calculation unit 44 may determine whether or not the vehicle 2 is charging based on the signal from the charging control unit 49. The wheel speed sensor 16C, which is close to the charging port 26, may output an incorrect value due to the influence of the magnetic field generated by the current supplied from an external power source. Therefore, when the vehicle 2 is charging, the vehicle speed can be calculated accurately by setting the vehicle speed to the average of the three values ​​with the smallest difference from the median among the four wheel speed values.

[0062] The vehicle control device 1 should control the HMI 23 to issue a warning when the vehicle speed of the vehicle 2 is below the stop threshold and an obstacle is approaching the vehicle 2. This prevents occupants from opening the doors unintentionally. In this case, the HMI 23 is a type of safety device, and the vehicle control device 1 and HMI 23 constitute an exit warning device. In this case, even if the battery 25 is in a charging state, the vehicle speed can be calculated accurately, allowing the vehicle control device 1 to appropriately control the HMI and issue a warning.

[0063] In addition to the airbag 24A and HMI 23, the safety devices may also include other devices such as the braking system 4. The vehicle control device 1 predicts the possibility of a collision between the vehicle 2 and the obstacle based on the vehicle speed of the vehicle 2, the speed of the obstacle, and the distance between the vehicle 2 and the obstacle, and when it determines that there is a possibility of the vehicle 2 colliding with the obstacle, it may drive the braking system 4 to decelerate the vehicle 2. In other words, the vehicle control device 1 and the braking system 4 constitute a Collision Mitigation Braking System (CMBS). The vehicle control device 1 may also drive the braking system 4 to decelerate the vehicle 2 when the collision margin time between the vehicle 2 and the obstacle is less than or equal to a predetermined value.

[0064] The above embodiments may also be described as follows:

[0065] One embodiment of the vehicle control device 1 includes an obstacle recognition unit 41 that recognizes obstacles around the vehicle 2 based on signals from a radar 11, a vehicle speed calculation unit 44 that calculates the vehicle speed based on a plurality of wheel speeds detected by a plurality of wheel speed sensors 16A to 16D provided on a plurality of wheels 20A to 20D, and a safety device control unit that controls a safety device (airbag 24A) based on the position of the obstacle and the vehicle speed, wherein the vehicle speed calculation unit 44 selects the wheel speed to be used to calculate the vehicle speed from among a plurality of wheel speeds based on the state of the vehicle 2.

[0066] According to this embodiment, the wheel speed used can be changed according to the state of the vehicle 2, and an appropriate vehicle speed can be calculated. As a result, a vehicle control device 1 can be provided that can activate a safety device based on the appropriate vehicle speed.

[0067] In the above embodiment, the safety device is an airbag 24A, and the safety device control unit deploys the airbag 24A when the acceleration of the vehicle 2 is equal to or greater than the deployment threshold, and may change the deployment threshold based on the collision margin time between the obstacle and the vehicle 2.

[0068] In this embodiment, the deployment threshold of the airbag 24A is changed based on the collision margin, and the collision margin is set based on the vehicle speed. Therefore, by calculating the appropriate vehicle speed, the airbag 24A as a safety device is properly controlled.

[0069] In the above embodiment, the vehicle speed calculation unit 44 may set the vehicle speed to the average of the two highest wheel speeds when the anti-lock braking system is activated.

[0070] According to this embodiment, the appropriate vehicle speed is calculated even when the anti-lock braking system is activated.

[0071] In the above embodiment, the vehicle speed calculation unit 44 may set the vehicle speed to the average value of the wheel speeds of the two driven wheels 20C and 20D, or the average value of the two wheel speeds with the lowest values, when the traction control system is in operation.

[0072] According to this embodiment, the appropriate vehicle speed is calculated even when the traction control system is in operation.

[0073] In the above embodiment, the vehicle speed calculation unit 44 may set the average of the four wheel speeds to the vehicle speed if the yaw rate of the vehicle 2 is equal to or greater than a predetermined determination value.

[0074] According to this embodiment, the appropriate vehicle speed is calculated even when vehicle 2 is turning.

[0075] In the above embodiment, the vehicle speed calculation unit 44 may set the vehicle speed to the average value of the three values ​​among the four wheel speed values ​​that have the smallest difference from the median value when the vehicle 2 is charging.

[0076] According to this embodiment, the appropriate vehicle speed is calculated even when some of the wheel speed sensors 16A to 16D are receiving electromagnetic waves associated with charging.

[0077] Another embodiment is a vehicle control method performed by a computer, which recognizes obstacles around the vehicle 2 based on signals from radar 11, calculates the vehicle speed based on multiple wheel speeds detected by multiple wheel speed sensors 16A to 16D provided on multiple wheels 20A to 20D, controls a safety device (airbag 24A) based on the position of the obstacles and the vehicle speed, and selects from the multiple wheel speeds to be used to calculate the vehicle speed based on the state of the vehicle 2.

[0078] According to this embodiment, the wheel speed used can be changed according to the state of the vehicle 2 to calculate an appropriate vehicle speed. As a result, a vehicle control method can be provided that can activate a safety device based on the appropriate vehicle speed.

[0079] Another embodiment is a control program for causing a computer to execute a vehicle control method, which causes the computer to recognize obstacles around the vehicle 2 based on signals from radar 11, calculate the vehicle speed based on multiple wheel speeds detected by multiple wheel speed sensors 16A to 16D provided on multiple wheels 20A to 20D, control a safety device (airbag 24A) based on the position of the obstacles and the vehicle speed, and select the wheel speed to be used to calculate the vehicle speed from among the multiple wheel speeds based on the state of the vehicle 2.

[0080] According to this embodiment, the wheel speed used can be changed according to the state of the vehicle 2 to calculate an appropriate vehicle speed. As a result, a control program can be provided for executing a vehicle control method that can activate a safety device based on the appropriate vehicle speed. [Explanation of symbols]

[0081] 1: Vehicle control system 2: Vehicles 11: Radar 16A: Wheel speed sensor 16B: Wheel speed sensor 16C: Wheel speed sensor 16D: Wheel speed sensor 18: Yaw rate sensor 20A: Drive wheels 20B: Drive wheels 20C: Driven wheel 20D: Driven wheel 24: Airbag Unit 24A: Airbag 24B: Inflator 25: Battery 26: Charging port 31: Processor 32: Memory 41: Obstacle Recognition Unit 42: Vehicle position recognition unit 43: Acceleration detection unit 44:Vehicle speed calculation section 45: Driving control unit 46: Approach Collision Prediction Unit 47: Airbag control unit 48: Hochi Department 49: Charging control unit

Claims

1. A vehicle control device, An obstacle recognition unit that recognizes obstacles around the vehicle based on signals from radar, A vehicle speed calculation unit calculates the vehicle speed based on multiple wheel speeds detected by multiple wheel speed sensors installed on multiple wheels, It has a safety device control unit that controls the safety device based on the position of the obstacle and the vehicle speed, The vehicle speed calculation unit is a vehicle control device that selects the wheel speed to be used for calculating the vehicle speed from among a plurality of wheel speeds based on the state of the vehicle.

2. The aforementioned safety device is an airbag. The vehicle control device according to claim 1, wherein the safety device control unit deploys the airbag when the vehicle's acceleration is greater than or equal to a deployment threshold, and changes the deployment threshold based on the collision margin time between the obstacle and the vehicle.

3. The vehicle control device according to claim 1, wherein the vehicle speed calculation unit sets the average of the two highest wheel speeds to the vehicle speed when the anti-lock braking system is activated.

4. The vehicle control device according to claim 1, wherein the vehicle speed calculation unit sets the vehicle speed to the average value of the two driven wheels, or the average value of the two wheel speeds with the lowest values, when the traction control system is in operation.

5. The vehicle control device according to claim 1, wherein the vehicle speed calculation unit sets the average of the four wheel speeds to the vehicle speed when the yaw rate of the vehicle is greater than or equal to a predetermined determination value.

6. The vehicle control device according to claim 1, wherein the vehicle speed calculation unit sets the vehicle speed to the average value of three of the four wheel speed values ​​that have small differences from the median value when the vehicle is charging.

7. A vehicle control method performed by a computer, Based on signals from radar, the system recognizes obstacles around the vehicle. The vehicle speed is calculated based on the multiple wheel speeds detected by multiple wheel speed sensors installed on multiple wheels. The safety device is controlled based on the position of the obstacle and the vehicle speed. A vehicle control method that selects the wheel speed to be used for calculating the vehicle speed from among a plurality of wheel speeds, based on the state of the vehicle.

8. A control program that causes a computer to execute a vehicle control method, Based on signals from radar, the system recognizes obstacles around the vehicle. The vehicle speed is calculated based on the multiple wheel speeds detected by multiple wheel speed sensors installed on multiple wheels. The safety device is controlled based on the position of the obstacle and the vehicle speed. A control program that, based on the state of the vehicle, selects the wheel speed to be used for calculating the vehicle speed from among a plurality of wheel speeds.

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