Vehicle control system

Abstract

The present invention provides a vehicle control system that can improve safety by assisting the driver's operation when parking a vehicle that is driven by a motor. [Solution] The control system includes a vehicle state detection unit configured to detect the state of the vehicle, a parking intention estimation unit configured to estimate the driver's intention to park the vehicle in a parking space based on the detected state of the vehicle, and a mode switching unit configured to switch the motor's torque characteristics from normal mode to parking mode when it is estimated that the driver is trying to park the vehicle. The relationship between the accelerator pedal depression amount and the motor torque in parking mode is set such that the motor torque is smaller in response to the accelerator pedal depression amount and / or the rate of increase of the motor torque in response to an increase in the accelerator pedal depression amount is smaller compared to the relationship between the accelerator pedal depression amount and the motor torque in normal mode.

Description

Technical Field

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

Background Art

[0002] Conventionally, when there is an obstacle in the traveling direction of a vehicle, torque suppression control for suppressing engine torque with respect to the accelerator pedal depression amount is known. For example, Patent Document 1 discloses a device that suppresses the output of an engine when the direction in which a wheel stopper installed to stop an automobile in a parking lot or the like is located matches the traveling direction of the automobile determined by the shift position. By suppressing the engine output, the device described in Patent Document 1 prevents accidentally operating the accelerator pedal and overrunning the wheel stopper, and colliding with nearby buildings or vehicles.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The device described in Patent Document 1 above is configured to suppress the output of the engine, which is the drive system of the vehicle, when a wheel chock is present in the direction of travel of the vehicle. Incidentally, in addition to an engine (internal combustion engine), a motor (electric motor) may be used as the drive system of a vehicle. In the case of an electric vehicle or hybrid vehicle that can be driven by a motor, the torque response to the amount of accelerator pedal depression is different from the torque response to the amount of accelerator pedal depression in a vehicle driven by an engine. Generally, the motor torque response to the amount of accelerator pedal depression is better than the engine torque response to the amount of accelerator pedal depression. For example, a vehicle driven by an engine accelerates slowly when the accelerator pedal is operated, but a vehicle driven by a motor accelerates quickly from low RPM when the accelerator pedal is operated.

[0005] Drivers unfamiliar with electric vehicles and other vehicles powered by motors may be confused by the difference in torque characteristics between engines and motors. For example, when parking a vehicle, drivers need to accelerate slowly at low speeds to perform delicate vehicle maneuvers. However, if a driver of an electric vehicle presses the accelerator pedal with the same force as in a gasoline-powered car, the vehicle may accelerate too much, increasing the risk of collision with a nearby wall or other vehicle. Therefore, there is a need to improve safety by assisting the driver's operation when parking motor-powered vehicles.

[0006] This invention has been made in view of the above-described circumstances, and its purpose is to provide a vehicle control system that can assist the driver's operation and improve safety when parking a vehicle that is driven by a motor. [Means for solving the problem]

[0007] According to one aspect of the present invention, a control system for a vehicle capable of running solely by motor drive includes: a vehicle state detection unit configured to detect the state of the vehicle; a parking intention estimation unit configured to estimate the driver's intention to park the vehicle in a parking space based on the state of the vehicle detected by the vehicle state detection unit; and a mode switching unit configured to switch the torque characteristics of the motor from a normal mode to a parking mode when the parking intention estimation unit estimates that the driver is attempting to park the vehicle, wherein the relationship between the accelerator pedal depression amount and the motor torque in the parking mode is set such that the motor torque is smaller with respect to the accelerator pedal depression amount and / or the rate of increase of the motor torque with respect to an increase in the accelerator pedal depression amount is smaller compared to the relationship between the accelerator pedal depression amount and the motor torque in the normal mode. [Effects of the Invention]

[0008] The vehicle control device according to the present invention can improve safety by assisting the driver's operation when parking a vehicle that is driven by a motor. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram showing a schematic configuration of a vehicle control system in one embodiment of the present invention. [Figure 2] Figure 2 shows the relationship between the amount the accelerator pedal is pressed and the motor torque. [Figure 3] Figure 3 is a flowchart showing the flow of the mode switching process in one embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, a vehicle control system according to one embodiment of the present invention will be described in detail with reference to the drawings. Figure 1 is a block diagram showing the schematic configuration of the vehicle control system in this embodiment. The vehicle control system 10 in this embodiment includes an imaging device 11, an obstacle detection device 12, an in-vehicle camera 13, an accelerator pedal sensor 14, a vehicle speed sensor 15, a control device 20, a drive device 30, a braking device 40, and a notification device 50, etc. The control system 10 in this embodiment is mounted on a vehicle and is configured to adjust the torque characteristics with respect to the amount of accelerator pedal depression in order to assist the driver's driving operation when parking the vehicle in a parking space.

[0011] The imaging device 11 is configured to image the area around the vehicle. The imaging device 11 includes, for example, a rear imaging unit capable of imaging the area behind the vehicle, a front imaging unit capable of imaging the area in front of the vehicle, a left-side imaging unit capable of imaging the area to the left of the vehicle, and a right-side imaging unit capable of imaging the area to the right of the vehicle. The imaging device 11 is configured to be able to image a 360-degree area around the vehicle using these imaging units. Each of these imaging units is configured as a digital camera having an image sensor such as a CCD or CMOS, and is configured to output information about the area around the vehicle as still images and / or moving images. The image data of the surrounding area captured by the imaging device 11 is input to the control device 20.

[0012] The obstacle detection device 12 is configured to detect obstacles around the vehicle and measure the relative distance between the vehicle and the obstacle. The obstacle detection device 12 includes, for example, a rear detection unit for detecting obstacles in the rear area of ​​the vehicle, a rear-side detection unit for detecting obstacles in the rear-side area, a front detection unit for detecting obstacles in the front area, and a front-side detection unit for detecting obstacles in the front-side area. These detection units consist of, for example, millimeter-wave radar, sonar sensors, and LiDAR (Light Detection and Ranging). Distance measurement by the obstacle detection device 12 is performed dynamically at a predetermined measurement cycle. The distance between the vehicle and the obstacle detected by the obstacle detection device 12 is input to the control device 20.

[0013] The imaging device 11 and / or obstacle detection device 12 function as an ambient environment detection device that detects the surrounding environment of a vehicle, including obstacles present around the vehicle. Obstacles present around the vehicle include objects in the direction of travel of the vehicle, wheel stops installed on the ground, and steps between the roadway and the sidewalk. Wheel stops are structures installed, for example, in parking lots or garages to stop the tires of a vehicle. Wheel stops are also called wheel stops or parking blocks and have a predetermined height (e.g., about 10-12 cm) from the ground. Steps are structures that distinguish the roadway from the sidewalk. Steps provided at vehicle access points for vehicles entering and exiting parking lots adjacent to the road have a height lower than the height of the wheel stops (e.g., about 2-5 cm). In the following description, "step" refers to a step provided at a vehicle access point. The ambient image data of the surrounding area captured by the imaging device 11 includes the parking space present around the vehicle.

[0014] The in-vehicle camera 13 is a driver monitoring camera located inside the vehicle. The in-vehicle camera 13 is installed, for example, on the instrument panel at the front of the vehicle and is configured to capture images of the area inside the vehicle, including the face of the driver seated in the driver's seat. The in-vehicle camera 13 is configured to capture images of the area inside the vehicle as still images and / or videos and to output the captured image data to the control device 20.

[0015] The accelerator pedal sensor 14 is located on the accelerator pedal (not shown) and detects the amount S the accelerator pedal is pressed by the driver. The vehicle speed sensor 15 detects the vehicle speed V. The accelerator pedal pressing amount S detected by the accelerator pedal sensor 14 and the vehicle speed V detected by the vehicle speed sensor 15 are input to the control device 20.

[0016] The control device 20 is composed of a computer including, for example, a ROM that stores programs and data, a CPU that performs arithmetic processing, a RAM that stores dynamic data and arithmetic processing results, and an input / output interface. The control device 20 is configured to control the entire vehicle control system 10 by performing the functions of a torque adjustment unit 20A that adjusts the torque when parking the vehicle in a parking space, and a false start suppression unit 20B that suppresses the torque to prevent the vehicle from starting unintentionally. In Figure 1, the control device 20 is shown to include the torque adjustment unit 20A and the false start suppression unit 20B, but the torque adjustment unit 20A and the false start suppression unit 20B may be implemented as an integrated unit of the control device 20, or they may be implemented as separate controllers. Details of the control of the control device 20 will be described later.

[0017] The drive unit 30 is configured to generate driving force for moving the vehicle and includes a motor (electric motor) 31 and an internal combustion engine 32. The drive unit 30 includes a motor controller and an engine controller (not shown) that control the driving force according to the amount S the driver presses down on the accelerator pedal or according to a control command from the control device 20. In this embodiment, the vehicle is a hybrid electric vehicle (HEV) equipped with a motor 31 and an engine 32 as the drive unit 30, and is configured to be able to run by driving only the motor 31 or only the engine 32.

[0018] The braking device 40 is a braking device that generates braking force in accordance with the amount the driver presses the brake pedal (not shown), and includes a brake controller and a brake actuator for generating braking force in accordance with a braking command from the vehicle system or the control device 20.

[0019] The notification device 50 is configured to notify the driver according to a command from the control device 20. The notification device 50 has, for example, a display, an indicator light, a speaker, etc., arranged on the instrument panel at the front of the vehicle, and provides information to the driver through vision and / or hearing. The notification device 50 may be configured to perform notification through, for example, touch. The notification device 50 provides the driver with information on, for example, the control being executed by the control device 20.

[0020] Next, the control executed by the control device 20 will be described in detail. As described above, the control device 20 is configured to be able to execute the functions of the torque adjustment unit 20A and the mis-start suppression unit 20B. First, the torque adjustment unit 20A will be described. The torque adjustment unit 20A includes a vehicle state detection unit 21, a driver state detection unit 22, a parking intention estimation unit 23, a mode switching unit 24, and a torque control unit 25.

[0021] The vehicle state detection unit 21 is configured to detect the state of the vehicle. The state of the vehicle includes, for example, the position information of the vehicle with respect to the parking space and the vehicle speed V of the vehicle. The vehicle state detection unit 21 recognizes the parking space existing around the vehicle based on, for example, the information on the surrounding environment of the vehicle input from the imaging device 11 and / or the obstacle detection device 12, and detects the position of the vehicle with respect to the recognized parking space. Whether a parking space exists or not is determined, for example, by detecting the white line (frame) that demarcates the parking space (parking section) and / or by detecting the wheel stopper installed at the far end of the parking space. The size of the parking space for standard parallel parking of a passenger car is such that the parking width is about 2.5 m to about 3 m and the parking depth (depth) is about 5 m to about 5.8 m. The vehicle state detection unit 21 may determine that a parking space exists when there is a space equivalent to a standard parking space between vehicles.

[0022] The vehicle state detection unit 21 recognizes the positional relationship between the vehicle and the parking space, and detects whether the vehicle is traveling toward the parking space in order to park in the parking space, or simply whether the vehicle is approaching the parking space. For example, when the vehicle is approaching the parking space and the parking space exists in the traveling direction of the vehicle, the vehicle state detection unit 21 determines that the vehicle is traveling toward the parking space in order to park.

[0023] In addition, when the driver attempts to park the vehicle in the parking space, the vehicle may make a U-turn after approaching the parking space. The vehicle state detection unit 21 is configured to continuously recognize the positional relationship between the vehicle and the parking space, detect that the vehicle makes a U-turn after approaching the parking space, and then detect that the vehicle is traveling toward the parking space. The vehicle state detection unit 21 also acquires the vehicle speed V detected by the vehicle speed sensor 15.

[0024] The driver state detection unit 22 is configured to detect, as the driver state, that the driver is visually recognizing the surroundings of the vehicle. For example, based on the image data including the face region of the driver input from the in-vehicle camera 13, the driver state detection unit 22 detects the face angle and / or the line-of-sight direction of the driver seated in the driver's seat. For example, the driver state detection unit 22 extracts feature points such as eyes, nose, and mouth from the image data of the face region, and detects the face angle (the orientation of the face) of the driver with respect to the longitudinal direction of the vehicle based on the extracted feature points. The driver state detection unit 22 may also detect the orientation of the driver's pupils from the image data of the face region and detect the line-of-sight direction with respect to the longitudinal direction of the vehicle.

[0025] The driver state detection unit 22 detects whether the driver is visually checking (observing) the surroundings of the vehicle based on the face angle and / or line of sight direction of the driver. In particular, when the vehicle is traveling toward a parking space, the driver state detection unit 22 detects whether the driver is visually recognizing the environment around the parking space. Further, the driver state detection unit 22 calculates the number of times the driver visually checks the surroundings of the vehicle. For example, when the face angle of the driver significantly changes from a state facing the front of the vehicle to the right or left direction to check the surroundings of the vehicle, the driver state detection unit 22 counts the number of visual checks as one time.

[0026] The parking intention estimation unit 23 is configured to estimate the parking intention of the driver who intends to park the vehicle in a parking space based on the state of the vehicle detected by the vehicle state detection unit 21. The parking intention estimation unit 23 estimates the parking intention of the driver based on the position information of the vehicle with respect to the parking space detected by the vehicle state detection unit 21 and the vehicle speed V of the vehicle. For example, when the vehicle is traveling toward a parking space and the vehicle speed V is greater than 0 and less than the first vehicle speed threshold V1 (0 < V < V1), the parking intention estimation unit 23 estimates that the driver intends to park the vehicle. The first vehicle speed threshold V1 is a threshold for determining whether the vehicle is traveling at a low speed to park, and is set in advance to an appropriate value (for example, about 10 to 15 km / h).

[0027] When the parking intention estimation unit 23 detects that the driver is making a turn in order to park the vehicle in a parking space, if the vehicle approaches the parking space at a low speed slower than the first vehicle speed threshold V1, makes a turn, and then is detected to be traveling toward the parking space, the parking intention estimation unit 23 may estimate that the driver intends to park the vehicle. By considering the movement of the vehicle before and after the turn, the parking intention of the driver can be accurately estimated.

[0028] The parking intention estimation unit 23 may further estimate the driver's parking intention by taking into account the driver's state detected by the driver state detection unit 22. The parking intention estimation unit 23 estimates that the driver intends to park the vehicle if, for example, it is determined that the driver is checking the area around the vehicle when the vehicle is traveling toward the parking space at a vehicle speed V slower than the first vehicle speed threshold V1. The parking intention estimation unit 23 determines that the driver is checking the area around the vehicle if, for example, the number of times the driver has visually checked the area calculated by the driver state detection unit 22 is greater than or equal to a predetermined number. The predetermined number of times for determining whether or not the driver is checking the area around the vehicle is set to an appropriate value in advance.

[0029] The mode switching unit 24 is configured to switch the torque characteristics of the motor 31 of the drive unit 30 between normal mode and parking mode according to the driver's parking intention estimated by the parking intention estimation unit 23. The mode switching unit 24 is configured to switch the torque characteristics of the motor 31 from normal mode to parking mode when the parking intention estimation unit 23 estimates that the driver is trying to park the vehicle. If the driver does not intend to park the vehicle, the mode switching unit 24 sets the torque characteristics of the motor 31 to normal mode.

[0030] The response of motor torque to accelerator pedal depression S is different from the response of engine torque to accelerator pedal depression S. Generally, the response of motor torque to accelerator pedal depression S is better than the response of engine torque to accelerator pedal depression S. For example, when a vehicle is driven by engine 32, it accelerates slowly when the accelerator pedal is pressed, but when a vehicle is driven by motor 31, it accelerates quickly from low RPM when the accelerator pedal is pressed.

[0031] When parking a vehicle in a parking space, the distance the vehicle travels until parking is complete is short, so the driver is required to accelerate gradually and perform delicate vehicle maneuvers. However, in a vehicle driven by motor 31, if the driver presses the accelerator pedal with the same feeling as in a vehicle driven by engine 32, the vehicle may accelerate too much. For example, if there is a step at the vehicle entrance for entering or exiting a parking lot adjacent to the road, the motor 31 has high torque when starting up, so the vehicle may accelerate rapidly the moment it goes over the step. In this case, there is a risk that the rapidly accelerating vehicle will collide with a nearby wall or other vehicle. However, for a driver unfamiliar with a vehicle driven by motor 31, it may be difficult to perform the same gentle acceleration operation as in a vehicle driven by engine 32 when parking.

[0032] Therefore, in this embodiment, when it is estimated that the driver is attempting to park the vehicle, the torque characteristics of the motor 31 of the drive unit 30 are switched from normal mode to parking mode, thereby assisting the driver in operating the vehicle in a manner suitable for parking.

[0033] Figure 2 shows an example of the relationship between accelerator pedal depression amount S and motor torque T in this embodiment. In Figure 2, the motor torque characteristics in normal mode are shown by the dashed line L1, and the motor torque characteristics in parking mode are shown by the solid line L2. The motor torque characteristics shown in Figure 2 represent the motor torque characteristics when the vehicle is traveling at a low speed (for example, about 10-15 km / h or less) for parking.

[0034] As shown in Figure 2, the motor torque characteristic L1 in normal mode is designed so that the motor torque T increases rapidly when the accelerator pedal depression amount S increases from 0, and the rate of increase of the motor torque T in response to the increase in accelerator pedal depression amount S becomes more gradual as the accelerator pedal depression amount S increases further.

[0035] As shown in Figure 2, the motor torque characteristic L2 in parking mode is designed so that the motor torque T increases gradually as the accelerator pedal depression amount S increases from 0, and the rate of increase of motor torque T in relation to the increase in accelerator pedal depression amount S becomes larger as the accelerator pedal depression amount S increases further. The motor torque characteristic in parking mode is designed to be similar to the torque characteristic of engine 32, with the rise of motor torque T in relation to accelerator pedal depression amount S suppressed. In the low-speed range during parking, the motor torque characteristic L2 in parking mode is set so that the motor torque T is smaller overall than the motor torque characteristic L1 in normal mode.

[0036] As shown in Figure 2, by setting the motor torque characteristic L2 in parking mode, when the driver presses the accelerator pedal, the motor torque T gradually increases, and the vehicle accelerates smoothly. Because the change in motor torque T in response to the change in accelerator pedal depression S is gradual, it becomes possible to precisely control the vehicle speed and achieve delicate vehicle operation. In addition, in parking mode, when the accelerator pedal depression S increases, the motor torque T increases rapidly, so when the driver presses the accelerator pedal to accelerate the vehicle, it becomes possible to accelerate with good responsiveness.

[0037] In this way, the parking mode modifies the torque characteristics of the motor 31 so that the motor torque T is smaller in response to the accelerator pedal depression amount S compared to the motor torque characteristics of the normal mode, and the rate of increase of motor torque T in response to an increase in accelerator pedal depression amount S is smaller. This assists the driver in parking operations. The mode switching unit 24 may be configured to inform the driver via the notification device 50 that the motor torque characteristics have been switched to parking mode and that driving operations are being supported. The notification device 50 informs the driver that parking mode has been selected, for example, by displaying it on a display installed on the instrument panel.

[0038] The mode switching unit 24 terminates the parking mode and switches the torque characteristics of the motor 31 to normal mode when predetermined termination conditions are met. The predetermined termination conditions include (A) to (D) below. The mode switching unit 24 terminates the parking mode when at least one of the following termination conditions (A) to (D) is met. (A) When parking in the parking space is complete (B) When the vehicle speed V of the vehicle becomes equal to or greater than the second vehicle speed threshold V2 (C) When the distance traveled by the vehicle since the parking mode was set, or the distance traveled by the vehicle since a maneuver was performed in parking mode, is greater than or equal to a predetermined distance. (D) When the accelerator pedal depression amount S is greater than or equal to the first threshold S1

[0039] (A) When parking in the parking space is complete The mode switching unit 24 recognizes the positional relationship of the vehicle relative to the parking space based on information about the surrounding environment of the vehicle input from the imaging device 11 and / or the obstacle detection device 12. The mode switching unit 24 determines that parking in the parking space is complete, for example, when the vehicle reaches the parking space and stops for a predetermined time or longer, or when the ignition switch (not shown) is turned off. If wheel stops are installed in the parking space, the mode switching unit 24 may also determine that parking in the parking space is complete when the distance between the wheel stops and the vehicle's wheels is within a predetermined value and the vehicle stops for a predetermined time or longer, or when the ignition switch is turned off. The mode switching unit 24 determines that termination condition (A) is met when parking in the parking space is complete.

[0040] (B) When the vehicle speed V of the vehicle becomes equal to or greater than the second vehicle speed threshold V2 The mode switching unit 24 determines that termination condition (B) has been met when the vehicle speed V in parking mode becomes equal to or greater than the second vehicle speed threshold V2. The second vehicle speed threshold V2 is a value greater than the first vehicle speed threshold V1 used to estimate the driver's intention to park, and is set in advance to an appropriate value (for example, about 20 km / h). If the vehicle is traveling at a relatively high speed (greater than or equal to the second vehicle speed threshold V2), the mode switching unit 24 determines that the driver is performing a driving operation other than a parking operation and terminates the parking mode.

[0041] (C) When the distance traveled by the vehicle since the parking mode was set, or the distance traveled by the vehicle since a maneuver was performed in parking mode, is greater than or equal to a predetermined distance. The mode switching unit 24 calculates the vehicle's mileage since the parking mode was set or the vehicle's mileage since a maneuver was performed in the parking mode. If the calculated mileage is greater than or equal to a predetermined distance, the mode switching unit 24 determines that the driver is performing a driving operation other than a parking operation and terminates the parking mode. The predetermined distance is set to an appropriate value based, for example, on the typical vehicle mileage from the start of a parking operation to the completion of parking. The predetermined distance for the vehicle's mileage since the parking mode was set and the predetermined distance for the vehicle's mileage since a maneuver was performed in the parking mode may be the same value or different values.

[0042] (D) When the accelerator pedal depression amount S is greater than or equal to the first threshold S1 The mode switching unit 24 determines that the driver is performing a driving operation other than parking if the accelerator pedal depression amount S is greater than or equal to the first threshold S1, and terminates the parking mode. The first threshold S1 is a value greater than the accelerator pedal depression amount S operated by the driver during a typical parking operation, and is set to an appropriate value in advance.

[0043] When at least one of the above termination conditions (A) to (D) is met, the mode switching unit 24 terminates the parking mode and switches the torque characteristics of the motor 31 to the normal mode. As a result, when the driver has not already performed a parking operation, the motor torque characteristics L1 of the normal mode, which has good torque response to the accelerator pedal depression amount S, is adopted instead of the motor torque characteristics L2 of the parking mode, which suppresses the motor torque T in relation to the accelerator pedal depression amount S.

[0044] The torque control unit 25 controls the motor 31 by sending a control command to the motor controller of the drive unit 30 to generate a motor torque T corresponding to the accelerator pedal depression amount S, according to the mode selected by the mode switching unit 24. The torque control unit 25 has torque maps corresponding to the motor torque characteristics L1 in normal mode and the motor torque characteristics L2 in parking mode. The torque control unit 25 refers to the torque map corresponding to the selected mode, generates a control command to generate a motor torque T corresponding to the accelerator pedal depression amount S, and sends it to the motor controller of the motor 31.

[0045] The torque control unit 25 may control the motor torque T so that when the torque characteristics of the motor 31 are switched from parking mode to normal mode by the mode switching unit 24, the motor torque T gradually transitions from the motor torque characteristics L2 of parking mode to the motor torque characteristics L1 of normal mode. The torque control unit 25 may, for example, prepare a torque map in advance for the transition from the motor torque characteristics L2 of parking mode to the motor torque characteristics L1 of normal mode, thereby suppressing torque fluctuations during mode switching.

[0046] Next, the unintended acceleration suppression unit 20B of the control device 20 will be described. The unintended acceleration suppression unit 20B includes an obstacle detection unit 26 and a torque suppression unit 27. The torque suppression control performed by the unintended acceleration suppression unit 20B is an unintended acceleration suppression function that reduces collision damage with an obstacle by suppressing the engine torque in relation to the amount the accelerator pedal is depressed when an obstacle is present in the direction of travel of the vehicle. Since the unintended acceleration suppression function is a well-known function, it will be briefly explained below.

[0047] The obstacle detection unit 26 is configured to detect obstacles in the direction of travel of the vehicle based on information about the surrounding environment of the vehicle input from, for example, the imaging device 11 and / or the obstacle detection device 12. The obstacle detection unit 26 detects the distance between the vehicle and the obstacle, and the height of the obstacle from the ground, for obstacles in the direction of travel of the vehicle. Here, obstacles that are subject to the unintended acceleration suppression function are objects that need to be avoided in collision with the vehicle and have a predetermined height from the ground. The predetermined height is, for example, the height of the wheel stop in a parking space (for example, about 10 to 12 cm). Therefore, the step provided in the vehicle entry area described above does not fall under the category of obstacles subject to the unintended acceleration suppression function.

[0048] The torque suppression unit 27 is configured to perform a misacceleration suppression function that limits the torque of the motor 31 or engine 32 in relation to the accelerator pedal depression amount S when the distance between the vehicle and an obstacle is less than or equal to a predetermined distance, the accelerator pedal depression amount S is greater than or equal to a second threshold S2, and the vehicle speed is less than or equal to a third vehicle speed threshold V3. The torque suppression unit 27 transmits a command to the drive unit 30 and the braking unit 40 to limit the torque to a predetermined value regardless of the accelerator pedal depression amount S.

[0049] The second threshold S2 for accelerator pedal depression amount S is a threshold for determining incorrect operation of the accelerator pedal and is set to an appropriate value in advance. Preferably, the second threshold S2 is greater than the first threshold S1 for determining the end of the parking mode described above. The predetermined distance and the third vehicle speed threshold V3 are each set to appropriate values ​​in advance.

[0050] As described above, the vehicle control system 10 according to this embodiment is configured to perform torque adjustment control by the torque adjustment unit 20A and torque suppression control by the unintended acceleration suppression unit 20B. The torque suppression control performed by the unintended acceleration suppression unit 20B is similar to the control by the torque adjustment unit 20A described above in that it suppresses the output torque in relation to the accelerator pedal depression amount S when the vehicle is traveling at a low speed. However, the torque adjustment unit 20A differs from the torque suppression control by the unintended acceleration suppression unit 20B in that it estimates whether or not the driver intends to park in order to suppress the motor torque T in relation to the accelerator pedal depression amount S. Furthermore, the torque adjustment unit 20A is configured to terminate the adjustment control of the motor torque T when the accelerator pedal depression amount S becomes equal to or greater than the first threshold S1 (when the termination condition (D) above is met), whereas the unintended acceleration suppression unit 20B is configured to start torque suppression control when the accelerator pedal depression amount S becomes equal to or greater than the second threshold S2.

[0051] The motor torque characteristic switching process when parking the vehicle in the parking space in this embodiment will be described in detail below using the flowchart in Figure 3. Figure 3 shows an example of the flow of mode switching control. The torque adjustment unit 20A of the control device 20 repeatedly executes the process shown in Figure 3 at a predetermined cycle.

[0052] In step S101, the vehicle state detection unit 21 acquires information about the surrounding environment of the vehicle detected by the imaging device 11 and the obstacle detection device 12. The vehicle state detection unit 21 also acquires vehicle speed information input from the vehicle speed sensor 15. Based on the environmental information around the vehicle, the vehicle state detection unit 21 recognizes parking spaces present around the vehicle and detects the positional relationship between the recognized parking space and the vehicle. For example, the vehicle state detection unit 21 detects whether the vehicle is driving towards a parking space in order to park in it.

[0053] In step S102, the driver state detection unit 22 acquires image data including the driver's face region input from the in-vehicle camera 13 as driver state information. Based on the image data including the driver's face region, the driver state detection unit 22 detects the face angle and / or gaze direction of the driver seated in the driver's seat. Based on the driver's face angle and / or gaze direction, the driver state detection unit 22 calculates the number of times the driver visually checks the area around the vehicle.

[0054] In step S103, the parking intention estimation unit 23 estimates the driver's intention to park the vehicle in the parking space based on the vehicle state acquired in step S101 and the driver state acquired in step S102. The parking intention estimation unit 23 estimates, for example, that the driver intends to park the vehicle if the vehicle is moving towards the parking space and the vehicle speed V is greater than 0 and less than the first vehicle speed threshold V1. The parking intention estimation unit 23 may further estimate that the driver intends to park the vehicle if the number of times the driver has visually checked the area around the vehicle, as calculated by the driver state detection unit 22, is greater than or equal to a predetermined number. Alternatively, the parking intention estimation unit 23 may estimate that the driver intends to park the vehicle if the vehicle approaches the parking space, makes a U-turn, then moves towards the parking space, and the vehicle speed V is greater than 0 and less than the first vehicle speed threshold V1.

[0055] If it is determined in step S103 that the driver has no intention to park, the process proceeds to step S104; if it is determined that the driver has an intention to park, the process proceeds to step S105. In step S104, the mode switching unit 24 sets the torque characteristics of the motor 31 to normal mode. As a result, the torque control unit 25 refers to a torque map corresponding to the motor torque characteristics L1 of the normal mode, for example, shown in Figure 2, and generates a control command to generate a motor torque T corresponding to the accelerator pedal depression amount S.

[0056] In step S105, the mode switching unit 24 switches the torque characteristics of the motor 31 from normal mode to parking mode. As a result, the torque control unit 25 refers to a torque map corresponding to the motor torque characteristics L2 of the parking mode, for example, as shown in Figure 2, and generates a control command to generate a motor torque T corresponding to the accelerator pedal depression amount S. The mode switching unit 24 also sends a command to the notification device 50 to inform the driver that parking mode has been selected.

[0057] In step S106, the mode switching unit 24 determines whether or not predetermined termination conditions are met and whether or not to terminate the parking mode. The mode switching unit 24 determines whether or not at least one of the termination conditions (A) to (D) described above is met. If none of the termination conditions (A) to (D) are met, the mode switching unit 24 determines that the parking mode will not be terminated and returns to step S105 to continue the parking mode.

[0058] When at least one of termination conditions (A) to (D) is met, the mode switching unit 24 determines that the parking mode has ended and proceeds to step S107. In step S107, the mode switching unit 24 switches the torque characteristics of the motor 31 from parking mode to normal mode. The mode switching unit 24 also sends a command to the notification device 50 to notify the driver that the mode has returned to normal mode. This completes the process.

[0059] The vehicle control system 10 according to this embodiment, as described above, can achieve the following effects.

[0060] (1) A vehicle control system 10 capable of driving solely by the motor 31 includes a vehicle state detection unit 21 configured to detect the state of the vehicle, a parking intention estimation unit 23 configured to estimate the driver's intention to park the vehicle in a parking space based on the state of the vehicle detected by the vehicle state detection unit 21, and a mode switching unit 24 configured to switch the torque characteristics of the motor 31 from normal mode to parking mode when the parking intention estimation unit 23 estimates that the driver is trying to park the vehicle. The relationship between the accelerator pedal depression amount S and the motor torque T in parking mode is set such that the motor torque T is smaller with respect to the accelerator pedal depression amount S and / or the rate of increase of the motor torque T with respect to an increase in the accelerator pedal depression amount S is smaller compared to the relationship between the accelerator pedal depression amount S and the motor torque T in normal mode.

[0061] Because the motor 31 has high torque at startup, in a vehicle driven solely by the motor 31, if the driver presses the accelerator pedal with the same force as in a vehicle driven by the engine 32, the vehicle may accelerate too much. However, for a driver unfamiliar with a vehicle driven by the motor 31, it may be difficult to perform the same gentle acceleration operation as in a vehicle driven by the engine 32 when parking. Therefore, when it is estimated that the driver is attempting to park the vehicle, the magnitude and / or rate of increase of the motor torque T in relation to the accelerator pedal depression amount S can be suppressed compared to the normal mode, thereby supporting the driver's delicate driving operations when parking. By performing torque adjustment control only when it is estimated that the driver has the intention to park, the characteristic of the motor 31, which is its good responsiveness to the accelerator pedal depression amount S, is not impaired when the driver is not performing a parking operation.

[0062] (2) When the mode switching unit 24 is set to parking mode, if the accelerator pedal depression amount S becomes greater than or equal to the first threshold S1, it switches the torque characteristics of the motor 31 to normal mode. If the accelerator pedal depression amount S becomes greater than or equal to the first threshold S1 and the accelerator pedal is depressed more than is normally done in parking operations, it is considered that the driver is no longer performing a parking operation. Therefore, by switching the motor torque characteristics from parking mode to normal mode, the vehicle can be driven according to the motor torque characteristics L1 with good responsiveness.

[0063] (3) The vehicle state detection unit 21 detects the vehicle's position relative to the parking space and the vehicle's speed V as the vehicle's state. The parking intention estimation unit 23 estimates that the driver is trying to park the vehicle if the vehicle is moving towards the parking space and the vehicle speed V is greater than 0 and less than the first vehicle speed threshold V1. Based on the positional relationship between the parking space and the vehicle and the vehicle speed V, it is possible to objectively estimate that the driver is trying to park the vehicle.

[0064] (4) A driver state detection unit 22 is further provided, which is configured to detect whether the driver is visually checking the area around the vehicle. The parking intention estimation unit 23 estimates that the driver is trying to park the vehicle if the number of times the driver has visually checked the area around the vehicle, as calculated by the driver state detection unit 22, is greater than or equal to a predetermined number. By estimating the driver's parking intention while taking into account whether or not the driver is visually checking the area around the vehicle, it is possible to estimate with high accuracy whether or not the driver is trying to park the vehicle.

[0065] (5) The vehicle state detection unit 21 detects the vehicle's position relative to the parking space and the vehicle's speed V as the vehicle's state. The parking intention estimation unit 23 estimates that the driver intends to park the vehicle if the vehicle approaches the parking space, makes a U-turn, then drives towards the parking space, and the vehicle speed V is greater than 0 and less than the first vehicle speed threshold V1. Even if the vehicle is moving towards the parking space at a low speed, it is possible that the parking space simply happens to be in the vehicle's direction of travel. By considering the vehicle's movement before and after the U-turn, the driver's parking intention can be estimated with high accuracy.

[0066] (6) When the parking mode is set, the mode switching unit 24 (A) When parking in a parking space is completed, or (B) When the vehicle speed becomes equal to or greater than the second vehicle speed threshold V2, (C) If the distance traveled by the vehicle since the parking mode was set, or the distance traveled by the vehicle since a maneuver was performed in parking mode, is greater than or equal to a predetermined distance, (D) If the accelerator pedal depression amount S is greater than or equal to the first threshold S1, The torque characteristics of motor 31 are switched to normal mode. If it is determined that the driver is not already performing a parking maneuver, the motor torque characteristics L1 of normal mode, which have good torque response to the accelerator pedal depression amount S, are adopted. This avoids unnecessarily suppressing the motor torque when a parking maneuver is not being performed.

[0067] (7) The vehicle is equipped with a motor 31 and an engine 32 for driving the vehicle. When the parking intention estimation unit 23 estimates that the driver is trying to park the vehicle, the mode switching unit 24 switches the torque characteristics of the motor 31 to parking mode when the vehicle is running on the motor 31, and does not change the torque characteristics of the engine 32 when the vehicle is running on the engine 32. The motor torque characteristics in parking mode are designed to be similar to the torque characteristics of the engine 32, with the rise of the motor torque T in response to the accelerator pedal depression amount S suppressed. Therefore, similar torque characteristics can be achieved during parking operations whether the vehicle is running on the motor 31 or on the engine 32.

[0068] (8) The vehicle control system 10 further includes an obstacle detection unit 26 configured to detect obstacles in the direction of travel of the vehicle, and a torque suppression unit 27 configured to perform torque suppression control that limits the torque of the motor 31 with respect to the accelerator pedal depression amount S when the distance between the vehicle and the obstacle is less than or equal to a predetermined distance, the accelerator pedal depression amount S is greater than or equal to a second threshold S2, and the vehicle speed V is less than or equal to a third vehicle speed threshold V3. The vehicle control system 10 is configured to perform two different torque controls: torque adjustment control to assist the driver's parking operation when the driver intends to park, and torque suppression control to suppress accidental acceleration of the vehicle in the event of an accidental operation of the accelerator pedal, etc., so that appropriate torque control can be performed depending on the scene.

[0069] (9) The torque suppression unit 27 executes torque suppression control when the obstacle detection unit 26 detects an obstacle of a predetermined height or higher. This makes it possible to execute unintended acceleration suppression control when there is an obstacle of a predetermined height or higher that needs to be avoided in collision with the vehicle. The step provided in the vehicle entrance is smaller than the predetermined height and does not fall under the category of obstacles that are subject to the unintended acceleration suppression function. Therefore, for example, when a vehicle enters the parking lot by going over the step provided in the vehicle entrance, it is possible to prevent a situation in which the unintended acceleration suppression function is executed and parking operations cannot be performed smoothly.

[0070] -Variations- (1) In the embodiments described above, the case in which the drive unit 30 has a motor 31 and an engine 32 has been described. However, the drive unit 30 may have only a motor 31 and omit the engine 32. In this case, the vehicle on which the vehicle control system 10 is installed is configured as an electric vehicle that runs solely on the power of the motor 31.

[0071] (2) In the above-described embodiment, the vehicle control system 10 includes a torque adjustment unit 20A and an unintended acceleration suppression unit 20B, but is not limited to this, and the unintended acceleration suppression unit 20B may be omitted.

[0072] (3) Figure 2 shows an example of the motor torque characteristics L2 in parking mode, but the motor torque characteristics in parking mode are not limited to those shown in Figure 2 and can be modified in various ways. For example, the motor torque characteristics L2 in parking mode may be designed so that the rate of increase of motor torque in response to an increase in accelerator pedal depression S remains unchanged, but only the magnitude of the motor torque T in response to the accelerator pedal depression S is smaller than that of the motor torque characteristics L1 in normal mode. Alternatively, the motor torque characteristics L2 in parking mode may be designed so that only the rate of increase of motor torque in response to an increase in accelerator pedal depression S is smaller than that of the motor torque characteristics L1 in normal mode.

[0073] (4) In the embodiments described above, an example was described in which the termination conditions for ending the parking mode include (A) to (D). However, the invention is not limited to this, and the termination conditions for ending the parking mode may include at least one of (A) to (D).

[0074] (5) In the above-described embodiment, the driver state detection unit 22 detects the driver's face angle or gaze direction based on image data including the face region input from the in-vehicle camera 13, and detects whether the driver is visually checking the area around the vehicle. However, it is not limited to this, and the system may be configured to determine whether the driver is visually checking the area around the vehicle using signals from a driver monitoring system that monitors the driver's state. The driver monitoring system is a system that detects the driver's face angle or gaze direction and monitors whether the driver is concentrating on driving without being distracted or falling asleep.

[0075] Although several embodiments of the present invention have been described above, it should be noted that the present invention is not limited to the above embodiments, and various further modifications and changes are possible within the scope of the present invention. [Explanation of Symbols]

[0076] 10. Vehicle control system 20 Control device 21 Vehicle status detection unit 22 Driver status detection unit 23 Parking Intent Estimation Unit 24 Mode switching section 25 Torque Control Unit 26 Obstacle detection unit 27 Torque suppression unit 31 Motor 32 Engine

Claims

1. A control system for a vehicle that can be driven solely by an electric motor, A vehicle state detection unit configured to detect the state of the vehicle, A parking intention estimation unit is configured to estimate the driver's intention to park the vehicle in a parking space based on the state of the vehicle detected by the vehicle state detection unit, When the parking intention estimation unit estimates that the driver is attempting to park the vehicle, a mode switching unit is configured to switch the torque characteristics of the motor from normal mode to parking mode. Equipped with, A vehicle control system in which the relationship between the amount of accelerator pedal depression and motor torque in the parking mode is set such that the motor torque is smaller in relation to the amount of accelerator pedal depression and / or the rate of increase of the motor torque in relation to an increase in the amount of accelerator pedal depression is smaller compared to the relationship between the amount of accelerator pedal depression and motor torque in the normal mode.

2. The vehicle control system according to claim 1, wherein the mode switching unit switches the torque characteristics of the motor to the normal mode when the amount of accelerator pedal depression becomes greater than or equal to a first threshold while the parking mode is set.

3. The vehicle status detection unit detects the vehicle's position information relative to the parking space and the vehicle's speed as the vehicle's status. The vehicle control system according to claim 1, wherein the parking intention estimation unit estimates that the driver intends to park the vehicle when the vehicle is traveling toward the parking space and the vehicle speed is less than a first vehicle speed threshold.

4. The vehicle further comprises a driver state detection unit configured to detect that the driver is visually observing the surroundings of the vehicle. The vehicle control system according to claim 3, wherein the parking intention estimation unit estimates that the driver intends to park the vehicle if the number of times the driver visually checks the area around the vehicle, calculated by the driver state detection unit, is greater than or equal to a predetermined number of times.

5. The vehicle status detection unit detects the vehicle's position information relative to the parking space and the vehicle's speed as the vehicle's status. The vehicle control system according to claim 1, wherein the parking intention estimation unit estimates that the driver intends to park the vehicle when the vehicle approaches the parking space, makes a U-turn, and then drives toward the parking space, and the vehicle speed is greater than 0 and less than a first vehicle speed threshold.

6. The mode switching unit operates when the parking mode is set. (A) When parking in the aforementioned parking space is completed, or (B) When the vehicle speed of the vehicle becomes equal to or greater than the second vehicle speed threshold, (C) If the distance traveled by the vehicle since the parking mode was set or the distance traveled by the vehicle since the reversal was performed in the parking mode is greater than or equal to a predetermined distance, (D) If the amount of accelerator pedal depression is equal to or greater than the first threshold, A vehicle control system according to claim 1, which switches the torque characteristics of the motor to the normal mode.

7. The vehicle comprises the motor and engine for driving the vehicle, The vehicle control system according to claim 1, wherein the mode switching unit, when it is estimated by the parking intention estimation unit that the driver is attempting to park the vehicle, switches the torque characteristics of the motor to the parking mode while the vehicle is running on the motor, and does not change the torque characteristics of the engine while the vehicle is running on the engine.

8. An obstacle detection unit configured to detect obstacles present in the direction of travel of the vehicle, A torque suppression unit is configured to perform torque suppression control to limit the torque of the motor in relation to the accelerator pedal depression amount when the distance between the vehicle and the obstacle is less than or equal to a predetermined distance, the amount of accelerator pedal depression is greater than or equal to a second threshold, and the vehicle speed is less than or equal to a third vehicle speed threshold. The vehicle control system according to claim 1, further comprising:

9. The vehicle control system according to claim 8, wherein the torque suppression unit performs the torque suppression control when the obstacle detection unit detects an obstacle of a predetermined height or greater.

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