Patent ID: 12243330

DESCRIPTION OF EMBODIMENTS

FIG.1is a diagram illustrating operation of the vehicle control device16of the embodiment in overview. Operation relating to vehicle control processing by the vehicle control device16disclosed herein will now be described in overview with reference toFIG.1.

The vehicle10has a vehicle control device16and a drive unit17. The vehicle control device16controls the drive unit17based on a predetermined driving plan. The drive unit17has an engine171, an electric motor172and an automatic transmission173. The vehicle10is a type known as a hybrid vehicle. The vehicle10may be an autonomous vehicle.

The drive unit17is controlled by the vehicle control device16to regulate output from the engine171and electric motor172. The drive unit17is also controlled by the vehicle control device16to regulate the gear stage or speed ratio of the automatic transmission173. Output from the engine171and electric motor172is converted by the automatic transmission173to rotary force with a predetermined rotational speed, and is transmitted to the tires20via an output shaft19.

The engine171generates drive power by combustion of a fuel such as gasoline. The electric motor172generates drive power by supply of electric power from a battery178.

The drive unit17has an electrical oil pump (EOP)175and a mechanical oil pump (MOP)176. The electrical oil pump175and mechanical oil pump176are controlled by the vehicle control device16to supply hydraulic pressure to a hydraulic control circuit174. The electrical oil pump175is actuated by an electric motor (not shown) to generate hydraulic pressure. The mechanical oil pump176is actuated by the engine171to generate hydraulic pressure. The automatic transmission173is controlled to engage and release clutches C1, C2and brakes B1, B2, B3, by the hydraulic pressure supplied from the hydraulic control circuit174.

The engine171is usually stopped when the vehicle10has been activated, and the vehicle control device16supplies hydraulic pressure that has been generated by the electrical oil pump175to the hydraulic control circuit174.

For the purpose of the present specification, “when the vehicle10has been activated” means the state where the vehicle control device16and drive unit17can be operated but the first hydraulic pressure P1allowing operation of the automatic transmission173has not been supplied to the automatic transmission173. Since drive power during this time has not yet been transmitted to the tires20, the vehicle10has not begun traveling.

After the vehicle10has been activated, the vehicle control device16estimates whether or not the driver is attempting to begin travel of the vehicle10, based on a monitor image of the area near the driving seat taken by a monitoring camera3.

When it has been estimated that the driver is not attempting to begin travel of the vehicle10, the vehicle control device16controls the electrical oil pump175to supply a second hydraulic pressure P2that is lower than the first hydraulic pressure P1which allows operation of the automatic transmission173having frictional engagement elements that can be engaged and disengaged by hydraulic pressure (the clutches C1, C2and brakes B1, B2, B3, etc.). The second hydraulic pressure P2may also be zero. In this case, the electrical oil pump175is controlled so that hydraulic pressure is not generated.

When the vehicle control device16has estimated that the driver is attempting to begin travel of the vehicle10, on the other hand, the vehicle control device16controls the electrical oil pump175to supply the first hydraulic pressure P1to the automatic transmission173. The hydraulic control circuit174is controlled by the vehicle control device16so that the first hydraulic pressure P1which allows operation of the automatic transmission173is supplied to the automatic transmission173. This causes the output of the electric motor172to be transmitted to the tires20via the automatic transmission173, to allow travel.

As explained above, during the period after the vehicle10has been activated and until it is estimated that the driver is attempting to begin travel of the vehicle10, the vehicle control device16of this embodiment controls the electrical oil pump175to supply the second hydraulic pressure P2that is lower than the first hydraulic pressure P1which allows operation of the automatic transmission173, thus allowing electric power consumption from the battery178to be reduced.

FIG.2is a general schematic drawing of a vehicle10in which the vehicle control device16of the embodiment is mounted. The vehicle control system1has a monitoring camera3, an activation switch4, an automatic control device15, a vehicle control device16and a drive unit17.

The monitoring camera3, activation switch4, automatic control device15, vehicle control device16and drive unit17are connected in a communicable manner via an in-vehicle network18conforming to the Controller Area Network standard.

The monitoring camera3is disposed in the vehicle compartment in a manner allowing it to photograph the area near the driving seat (not shown). Monitor images representing the area near the driving seat that have been taken by the monitoring camera3may include the face of the driver who is driving the vehicle10. The monitoring camera3is an example of a photographing device that takes monitor images.

The monitoring camera3photographs a monitor image including the face of the driver by photographing the area around the driving seat31at a monitor imaging time with a predetermined cycle. The predetermined cycle may be 0.1 to 1.0 second, for example. The predetermined cycle is not limited to this time range, however. Each time a monitor image is taken, the monitoring camera3outputs the monitor image and monitor imaging time to the vehicle control device16, etc. via the in-vehicle network18.

The monitoring camera3has a 2D detector composed of an array of photoelectric conversion elements with infrared sensitivity, such as a CCD or C-MOS, and an imaging optical system that forms an image of the photographed region on the 2D detector. The monitoring camera3preferably has a lighting device in addition to the 2D detector. The lighting device is an LED (light emitting diode), and for example, it may consist of two near-infrared LEDs situated on either side of the imaging optical system. Illuminating the driver with near-infrared light allows the driver's face to be photographed without causing discomfort for the driver even during low-illuminance periods such as nighttime.

The activation switch4is disposed in the vehicle compartment so as to allow operation by the driver seated in the driving seat. The activation switch4generates an operation signal in response to the driver operation and outputs the operation signal to the automatic control device15and vehicle control device16, etc. via the in-vehicle network18. Based on the operation signal, the vehicle10transitions to an accessory on state, an ignition on state and an actuatable state for the engine171and/or electric motor172.

The automatic control device15has an automatic control mode in which the vehicle10is driven primarily by the automatic control device15, and a manual control mode in which the vehicle10is driven primarily by the driver. In automatic control mode, the automatic control device15generates a driving plan for control of actions such as steering, engine actuation and braking, etc. based on detection information from a sensor (not shown) mounted in the vehicle10, and outputs the driving plan to the vehicle control device16via the in-vehicle network18.

In manual control mode, the automatic control device15generates a manual control signal for control of actions of the vehicle10such as steering, engine actuation and braking, etc. based on operation by the driver, and outputs the manual control signal to the vehicle control device16.

In automatic control mode, driving is primarily executed by the automatic control device15. Automatic control mode may also include driving at the self-driving levels of 2 to 5. In manual control mode, driving is primarily executed by the driver. Manual control mode may also include driving at the self-driving levels of 0 to 1.

Automatic control mode can be carried out in regions where a high precision map is available for control of the vehicle10. When the point where the vehicle10has been activated is in a region where the high precision map is not available, therefore, the driver drives the vehicle10in manual control mode, with the vehicle10being able to travel under automatic control mode after having traveled to a region where the high precision map is available.

The vehicle control device16carries out control processing and estimation processing. For this purpose, the vehicle control device16has a communication interface (IF)21, a memory22and a processor23. The communication interface21, memory22and processor23are connected via signal wires24. The communication interface21has an interface circuit to connect the vehicle control device16with the in-vehicle network18.

The memory22is an example of a memory unit, and it has a volatile semiconductor memory and a non-volatile semiconductor memory, for example. The memory22stores an application computer program and various data to be used for information processing carried out by the processor23of each device.

All or some of the functions of the vehicle control device16are carried out by functional modules driven by a computer program operating on the processor23, for example. The processor23has a control unit231and an estimating unit232. Alternatively, the functional module of the processor23may be a specialized computing circuit in the processor23. The processor23comprises one or more CPUs (Central Processing Units) and their peripheral circuits. The processor23may also have other computing circuits such as a logical operation unit, numerical calculation unit or graphic processing unit.

In automatic control mode, the control unit231controls each unit of the vehicle10based on the current location of the vehicle10and the vehicle speed and yaw rate, as well as on the driving plan generated by the automatic control device15. For example, the control unit231determines the steering angle, acceleration and angular acceleration of the vehicle10according to the driving plan and the speed and yaw rate of the vehicle10, and sets the amount of steering, and the accelerator or brake level so as to match that steering angle, accelerator level and angular acceleration. The control unit231also outputs a control signal corresponding to a set steering amount, to an actuator (not shown) that controls the steering wheel for the vehicle10, via the in-vehicle network18. The vehicle control device16also outputs a control signal corresponding to the set accelerator level, to the drive unit17of the vehicle10, via the in-vehicle network18. Alternatively, the vehicle control device16may output a control signal corresponding to a set brake level to the brake (not shown) of the vehicle10, via the in-vehicle network18.

In manual control mode, the control unit231controls each unit of the vehicle10based on manual control signals generated by the automatic control device15. Details regarding operation by the vehicle control device16will be described in detail below.

As shown inFIG.1, the drive unit17has an engine171, an electric motor172, an automatic transmission173, a hydraulic control circuit174, an electrical oil pump175, a mechanical oil pump176, an oil temperature sensor177and a battery178.

Operation of the rotational speed of the engine171and electric motor172is controlled by the vehicle control device16. The gear stage or speed ratio of the automatic transmission173is also controlled by the vehicle control device16. The gear stage or speed ratio of the automatic transmission173can be set according to the speed of the vehicle10and the required rotary force (torque). For example, when the speed of the vehicle10and gear stage are set, the rotational speed output from the electric motor172to the automatic transmission173becomes set, and this rotational speed is used as the basis for appropriately setting the rotational speed output from the engine171to the electric motor172. It is often the case when the vehicle10is traveling at a constant speed under low load, that the engine171is stopped and drive power is obtained from the electric motor172. The electric motor172may also consist of several motors.

The gear stage and speed ratio of the automatic transmission173are controlled by engagement and release of the clutches C1, C2and brakes B1, B2, B3by the hydraulic pressure from the hydraulic control circuit174.

The electrical oil pump175or mechanical oil pump176supplies hydraulic pressure to the hydraulic control circuit174. The hydraulic control circuit174controls the hydraulic pressure supplied to the automatic transmission173in response to a friction material hydraulic pressure command output from the vehicle control device16, thereby allowing the gear stage or speed ratio to be controlled.

The electrical oil pump175and mechanical oil pump176can supply the first hydraulic pressure P1which allows engagement and disengagement of the clutches C1, C2and brakes B1, B2, B3, to the automatic transmission173.

The mechanical oil pump176is actuated by an engine171to generate hydraulic pressure. The vehicle control device16usually stops the engine171when the vehicle10has been activated, and supplies hydraulic pressure that has been generated by the electrical oil pump175to the hydraulic control circuit174. Since the engine171is therefore usually stopped when the vehicle10has been activated, the mechanical oil pump176is also stopped.

When the vehicle10has been activated and the storage level of the battery178is below a predetermined reference storage level, the vehicle control device16actuates the engine171and charges the battery178by electric power generated by the electric motor172. In this case, the vehicle control device16stops the electrical oil pump175and supplies hydraulic pressure generated by the mechanical oil pump176to the hydraulic control circuit174.

The oil temperature sensor177detects the oil temperature in the hydraulic control circuit174and outputs the oil temperature to the vehicle control device16via the in-vehicle network18.

The automatic control device15and vehicle control device16are electronic control units (ECU), for example. ForFIG.2, the automatic control device15and the vehicle control device16were described as separate devices, but these may also be constructed as a single device.

FIG.3is an example of an operation flow chart for vehicle control processing by the vehicle control device16of the embodiment. Vehicle control processing by the vehicle control device16will be described below with reference toFIG.3. After having activated the vehicle10, the vehicle control device16carries out vehicle control processing according to the operation flow chart shown inFIG.3, at a vehicle control time with a predetermined cycle. The cycle for the vehicle control time is preferably at least the length of the cycle for the monitor imaging time.

The estimating unit232first acquires a monitor image that has been taken by the monitoring camera3(step S101). The area near the driving seat is shown in the monitor image, and may include the face of the driver.

The estimating unit232then estimates whether or not the driver is attempting to begin travel of the vehicle10, based on the monitor image (step S102). This estimation processing is described in detail below.

When it has been estimated that the driver is attempting to begin travel of the vehicle10(step S102—Yes), the control unit231decides to supply the first hydraulic pressure P1to the automatic transmission173(step S103), and the series of processing steps is complete. The control unit231controls the electrical oil pump175to supply the automatic transmission173with the first hydraulic pressure P1which allows operation of the automatic transmission173. The vehicle10can thus begin to travel.

When it has been estimated that the driver is not attempting to begin travel of the vehicle10(step S102—No), on the other hand, the control unit231decides to supply the second hydraulic pressure P2which is lower than the first hydraulic pressure P1(step S104), and the series of processing steps is complete. The control unit231controls the electrical oil pump175to supply the automatic transmission173with the second hydraulic pressure P2. A lower second hydraulic pressure P2is preferred from the viewpoint of reducing electric power consumption. A higher second hydraulic pressure P2, on the other hand, is preferred from the viewpoint of rapidly supplying the first hydraulic pressure to the automatic transmission173when it has been estimated that the driver is attempting to begin travel of the vehicle10. The second hydraulic pressure P2can be set in a range of 20% to 80% of the first hydraulic pressure P1, for example. The second hydraulic pressure P2may also be zero. In this case, the electrical oil pump175is controlled so that hydraulic pressure is not generated.

FIG.4is an example of an operation flow chart for estimation processing by the vehicle control device of the embodiment. In step S102described above, the estimating unit232estimates whether or not the driver is attempting to begin travel of the vehicle10, according to the operation flow chart shown inFIG.4.

First, the estimating unit232determines whether or not the face of the driver is oriented toward the front of the vehicle10(step S201). The orientation of the face of the driver is represented by the angles in the horizontal direction and vertical direction between the traveling direction of the vehicle10and the direction in which the face of the driver is facing, for example. The estimating unit232has a classifier that has been trained to detect facial aspects such as eye corners, inner eye corners and cheilions from images. The estimating unit232inputs monitor images into the classifier to determine the locations of predetermined facial aspects in the monitor images. The estimating unit232also compares the locations of the predetermined facial aspects detected from the monitor image against a standard facial three-dimensional model. The angle of the face in a three-dimensional model in which the location of each facial aspect maximally matches the aspect location detected from the monitor image is detected as the angle of the face in the monitor image.

The classifier may be a convolutional neural network (CNN) having multiple layers connected in series from the input end to the output end, for example. Facial images including predetermined facial aspects are previously input into the CNN as teacher data for learning, whereby the CNN functions as a classifier to identify the locations of predetermined facial aspects.

Publicly known technology may also be used to determine the orientation of the face of the driver based on monitor images. For example, the technology disclosed in Japanese Unexamined Patent Publication No. 2019-87150 may be used. The estimating unit232may also estimate the direction of the driver's line of sight, using the direction of the driver's line of sight as the orientation of the face of the driver.

The estimating unit232determines that the driver is facing the front of the vehicle10if, for example, the angle of orientation of the face of the driver is within a predetermined angle (such as 30°) either to the left or right with respect to the front as the traveling direction of the vehicle10and is within a predetermined angle (such as 15°) either above or below with respect to the traveling direction of the vehicle10.

When the orientation of the face of the driver is toward the front of the vehicle10(step S201—Yes), the estimating unit232determines whether or not a state in which the orientation of the face of the driver is oriented toward the front of the vehicle10has continued for a first time period T1(step S203).

If the face of the driver has been oriented toward the front of the vehicle10for the length of the first time period T1(step S202—Yes), the estimating unit232estimates that the driver is attempting to begin travel of the vehicle10(step S202), and the series of processing steps is complete. If the face of the driver has not been oriented toward the front of the vehicle10for the length of the first time period T1(step S202—No), processing returns to step S201.

If the orientation of the face of the driver is not toward the front of the vehicle10(step S201—No), on the other hand, the estimating unit232estimates that the driver is not attempting to begin travel of the vehicle10(step S204), and the series of processing steps is complete.

FIG.5(A)toFIG.5(F)show examples of timing charts for illustration of vehicle control processing by the vehicle control device16of the embodiment. Vehicle control processing by the vehicle control device16will now be explained with reference to the timing charts shown inFIG.5.

FIG.5(A)shows the relationship between vehicle10state and time,FIG.5(B)shows the relationship between electrical oil pump175state and time, andFIG.5(C)shows the relationship between friction material hydraulic pressure command and time.FIG.5(D)shows the relationship between hydraulic pressure supplied to the automatic transmission173and time,FIG.5(E)shows the relationship between shift position and time, andFIG.5(F)shows the relationship between speed of the vehicle10and time.

First, as shown inFIG.5(A), the driver operates the activation switch4, activating the vehicle10at time T1. The vehicle control device16estimates that the driver is not attempting to begin travel of the vehicle10. The vehicle control device16also decides to supply the second hydraulic pressure P2that is lower than the first hydraulic pressure P1which allows operation of the automatic transmission173. At this time, the vehicle control device16has the electrical oil pump175in a stopped state. Incidentally, the vehicle control device16may also actuate the electrical oil pump175to supply the second hydraulic pressure P2that is lower than the first hydraulic pressure P1to the automatic transmission173.

As shown inFIG.5(B), at time T2, the vehicle control device16estimates that the driver is attempting to begin travel of the vehicle10. The vehicle control device16operates the electrical oil pump175to begin supply of the automatic transmission173with the first hydraulic pressure P1.

In addition, as shown inFIG.5(C), the vehicle control device16outputs a friction material hydraulic pressure command to the hydraulic control circuit174to switch to first gear (friction material hydraulic pressure command ON). In response, the hydraulic pressure of the automatic transmission173increases to the first hydraulic pressure P1, as shown inFIG.5(D).

As shown inFIG.5(E), at time T3, the driver operates the shift selector (not shown) to change the shift position from P range to D range. Output from the electric motor172is converted by the automatic transmission173to rotary force with a predetermined rotational speed, and is transmitted to the tires20via an output shaft19. The speed of the vehicle10gradually increases in response, as shown inFIG.5(F).

In the example of vehicle control processing described above, the electrical oil pump175either stops during the period from time T1to time T2, or is controlled to supply lower hydraulic pressure than the first hydraulic pressure, thus allowing electric power consumption to be reduced.

In contrast, when the electrical oil pump175has been operated immediately after activation of the vehicle10, as represented by the dot and dash line inFIG.5(B), the first hydraulic pressure P1is supplied to the automatic transmission173in response. Therefore, a greater amount of electric power is consumed by operation of the electrical oil pump175until the time that the driver changes the shift position from P range to D range at time T3.

As explained above, during the period after the vehicle has been activated and until it is estimated that the driver is attempting to begin travel of the vehicle, the vehicle control device of this embodiment controls the electrical oil pump to supply a lower hydraulic pressure than the hydraulic pressure which allows operation of the transmission, thus allowing electric power consumption from the battery to be reduced.

The vehicle control device, the computer program for vehicle control and the method for controlling a vehicle according to the embodiment described above may incorporate appropriate modifications that are still within the gist of the disclosure. Moreover, the technical scope of the disclosure is not limited to these embodiments, and includes the invention and its equivalents as laid out in the Claims.

For example, the estimating unit232may estimate that the driver is attempting to begin travel of the vehicle10if the face of the driver is oriented toward the front of the vehicle10for a second time period T2that is shorter than the first time period T1, when the temperature of the oil that causes operation of the automatic transmission173is lower than a predetermined reference temperature. Since a low oil temperature increases the viscosity of the oil, more time is required for the hydraulic pressure of the automatic transmission173to increase in response to a friction material hydraulic pressure command. By shortening the time required for estimation, therefore, the hydraulic pressure is increased earlier and the vehicle10is brought to a travel-capable state more rapidly.

When the vehicle10has been activated and the storage level of the battery178is below a predetermined reference storage level, the vehicle control device16actuates the engine171and charges the battery178by electric power generated by the electric motor172. In this case, the vehicle control device16stops the electrical oil pump175and supplies hydraulic pressure generated by the mechanical oil pump176to the hydraulic control circuit174. Thus, when the mechanical oil pump176is being operated while the vehicle10has been activated, the vehicle control device16may control the mechanical oil pump176to supply the second hydraulic pressure P2that is lower than the first hydraulic pressure P1when it has been estimated by the estimating unit232that the driver is not attempting to begin travel of the vehicle10, and to control the mechanical oil pump176to supply the first hydraulic pressure P1to the automatic transmission173when it has been estimated by the estimating unit232that the driver is attempting to begin travel of the vehicle10.