JP2024170023A - Braking/driving force calculation method and braking/driving force calculation device - Google Patents

Abstract

To provide braking/driving force calculation method and a braking/driving force calculation device which can calculate braking/driving force which applies to a vehicle according to sensitiveness which feels discomfort of an operator for braking/driving control of the vehicle.SOLUTION: Braking/driving force calculation method and a braking/driving force calculation device 100 which can calculate braking/driving force according to sensitiveness which feels discomfort of an operator for braking/driving control of a vehicle determines the sensitiveness at which the operator feels discomfort for the braking/driving control in a determination part 130 on the basis of condition of the operator and calculates braking force more highly than when it is determined that the sensitiveness is high or calculates the driving force lowly if it is determined that the sensitiveness is low in a calculation part 140.SELECTED DRAWING: Figure 1

Description

The present invention relates to a driving/braking force calculation method and a driving/braking force calculation device.

A technology is known that detects the driver's pulse rate while driving, determines a threshold value that decreases as the pulse rate increases, and detects a decline in the driver's driving ability if the absolute value of the actual lateral acceleration is equal to or greater than the threshold value, and automatically reduces engine output without driver operation (Patent Document 1).

Japanese Patent Application Publication No. 6-127285

For example, when vehicle braking control is performed automatically without driver operation, the driver may feel discomfort in response to vehicle control, such as a sudden deceleration. In order to reduce this discomfort, it is necessary to calculate the braking/driving force to be applied to the vehicle according to the driver's sensitivity, such as increasing the braking force when the driver's sensitivity to discomfort is low. However, the technology described in Patent Document 1 is a technology that only controls the driving state of the vehicle to compensate for the decline in the driver's driving ability, and therefore has the problem of being unable to calculate the braking/driving force to be applied to the vehicle according to the driver's sensitivity.

The problem that this invention aims to solve is to provide a braking/driving force calculation method and device that can calculate the braking/driving force to be applied to a vehicle according to the driver's sensitivity to the vehicle's braking/driving control.

This invention solves the above problem by determining the sensitivity to braking control at which the driver feels uncomfortable based on the driver's state, and when the sensitivity is determined to be low, calculating a higher braking force than when the sensitivity is determined to be high.

The present invention solves the above problem by determining the sensitivity at which the driver feels uncomfortable with drive control based on the state of the driver of the vehicle, and when it is determined that the sensitivity is low, it calculates a lower drive force than when it is determined that the sensitivity is high.

According to the present invention, the braking/driving force to be applied to the vehicle can be calculated according to the sensitivity to the driver's discomfort in response to the vehicle's braking/driving control.

1 is a block diagram of a driving assistance system including a braking/driving force calculation device according to an embodiment of the present invention; FIG. 11 is a diagram showing the relationship between the deceleration gradient and a sense of discomfort felt by the driver. FIG. 13 is a diagram showing a graph relating to setting of a deceleration gradient. FIG. 13 is a graph showing the setting of the deceleration gradient. FIG. 11 is a diagram showing the effect on vehicle performance caused by the presence or absence of braking/driving control during cornering. FIG. 2 is a block diagram of a calculation unit shown in FIG. 1 . 4 is a flowchart showing the processing procedure of a braking/driving force calculation method according to the embodiment; 5 is a flowchart for explaining an example of a procedure of a driver's state recognition process according to the embodiment; 10 is a flowchart showing a process for determining the sensitivity of discomfort according to the present embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a case where a vehicle braking/driving force calculation device according to an embodiment of the present invention is applied to a driving assistance system mounted on a vehicle will be described as an example. FIG. 1 is a diagram showing a block configuration of the driving assistance system. The driving assistance system 1 supports driving of a vehicle by controlling the driving of the vehicle. The driving assistance system 1 can be applied not only to driving of a vehicle by autonomous driving control, but also to supporting driving of a vehicle by manual driving by a driver. The driving assistance system 1 of this embodiment includes a voice recognition device 20, an in-vehicle camera 30, a vehicle information acquisition device 40, a braking/driving force calculation device 100, and a vehicle controller 200. Each device is mounted on a vehicle and is connected by a CAN (Controller Area Network) or other in-vehicle LAN to exchange information with each other.

When applied to autonomous vehicle driving control, the driving assistance system 1 autonomously controls both speed control and steering control, and can also be applied to cases where one of speed control and steering control is autonomously controlled and the other is manually controlled. Specifically, in the driving assistance system 1, the braking/driving force calculation device 100 calculates the braking/driving force for braking/driving the vehicle, and the braking device 220 and the driving device 230 execute braking/driving control of the vehicle based on the calculated braking/driving force. The driving assistance system 1 may also be equipped with a steering device 240 and execute steering control of the vehicle to assist in driving the vehicle.

The voice recognition device 20 measures the sound inside the vehicle cabin and recognizes the voices of the occupants inside the vehicle cabin by performing voice recognition processing on the measured sound inside the vehicle cabin. The voice recognition device 20 outputs voice information including the recognized voices of the occupants inside the vehicle cabin to the braking/driving force calculation device 100 as information related to the conversation state. Note that in this embodiment, the voice recognition device 20 may measure the sound inside the vehicle cabin and obtain sound pressure information for the measured sound inside the vehicle cabin.

The vehicle-mounted camera 30 acquires image information capturing the situation inside the vehicle cabin, including the driver's face. The vehicle-mounted camera 30 is, for example, a camera installed inside the vehicle cabin, and captures the situation inside the vehicle cabin, including the driver's face, to acquire image information. The vehicle-mounted camera 30 outputs the acquired image information, including the driver's face, to the braking/driving force calculation device 100 as information related to the conversation state.

The vehicle information acquisition device 40 acquires information regarding the vehicle state, the driving operation state of the vehicle, and the operation state of switches. Information regarding the vehicle state includes the vehicle's current location, vehicle speed, longitudinal acceleration, lateral acceleration, and steering angle. Information regarding the driving operation state of the vehicle includes accelerator operation information regarding accelerator operation by the driver, and brake operation information regarding brake operation by the driver. Accelerator operation information includes, for example, accelerator opening and wheel end drive torque of the drive device 230. Brake operation information includes, for example, brake pressure and wheel end regenerative torque of the drive device 230.

The information on the state of switch operation includes, for example, information on the on/off status of switches installed in the driver's seat and whether the settings have been operated. The switches are, for example, switches installed in the center console or switches installed on the steering wheel. These may be obtained from the vehicle's braking device 220 and driving device 230, or from each sensor in the vehicle. The information obtained by the vehicle information acquisition device 40 is output to the braking/driving force calculation device 100.

The vehicle controller 200 is an on-board computer such as an electronic control unit (ECU), and electronically controls the drive mechanism that governs the operation of the vehicle. The vehicle controller 200 controls the drive device 230, the brake device 220, and the steering device 240 included in the drive mechanism to drive the host vehicle along a target route. The drive mechanism includes an electric motor and/or an internal combustion engine as a drive source for driving, a power transmission device including a drive shaft and an automatic transmission that transmits the output from these drive sources to the drive wheels, the drive device 230 that controls the power transmission device, and the brake device 220 that brakes the wheels. The vehicle controller 200 generates control signals for each of these drive mechanisms based on input signals from the driver's accelerator operation and brake operation, and the braking and driving forces acquired from the braking and driving force calculation device 100, and executes driving control including acceleration and deceleration of the vehicle. By sending control information to the drive mechanism, driving control including acceleration and deceleration of the vehicle can be performed autonomously.

The vehicle controller 200 controls the steering device 240 so that the vehicle travels while maintaining a predetermined lateral position with respect to the travel path (trajectory). The steering device 240 is equipped with a steering actuator. The steering actuator includes a motor and the like that is attached to the steering column shaft. The steering device 240 performs steering control of the vehicle based on a control signal obtained from the vehicle controller 200 or an input signal by the driver's steering operation.

The braking/driving force calculation device 100 according to this embodiment will be described below. The braking/driving force calculation device 100 calculates the braking force for braking the vehicle or the driving force for driving the vehicle. As shown in FIG. 1, the braking/driving force calculation device 100 according to this embodiment includes a processor 10. The processor 10 is a computer including a ROM 12 in which a program for executing the calculation of the braking/driving force is stored, a CPU 11 as an operating circuit that functions as the braking/driving force calculation device 100 by executing the program stored in the ROM 12, and a RAM 13 that functions as an accessible storage device. The processor 10 includes a recognition unit 120, a determination unit 130, and a calculation unit 140 as functional blocks. The processor 10 according to this embodiment executes each function by cooperation between the software for implementing each of the above functions or executing each process and the above-mentioned hardware.

The recognition unit 120 recognizes the state of the driver of the vehicle. The state of the driver is whether or not the driver is highly concentrated on driving. In this embodiment, when the driver is talking and/or operating switches, the state of the driver is recognized as a state in which the driver's concentration on driving is not high, i.e., low. If the driver is performing an action other than driving, such as talking or operating switches, the driver's attention is directed to actions other than driving, and therefore the driver's concentration on driving is considered to be lower than when the driver is only driving.

The recognition unit 120 recognizes the state of the driver based on information on the driver's conversation state and the operation state of the switches. Specifically, the recognition unit 120 recognizes whether the driver is talking or not based on the voice information of the occupants recognized by the voice recognition device 20 and the image information of the driver's face captured by the in-vehicle camera 30. For example, the recognition unit 120 recognizes that the occupants are talking from the voice information of the occupants and/or recognizes that the driver's mouth is moving from the image of the driver's face, and recognizes that the driver is talking. The recognition unit 120 may also perform a process to remove the vehicle's running sound and the sound emitted by in-vehicle devices such as a navigation system from the sound pressure information acquired by the voice recognition device 20, and recognize that the occupants are talking if the processed sound is equal to or higher than a predetermined sound pressure.

The recognition unit 120 also recognizes whether the driver is operating the switches based on the on/off and setting states of the switches from the vehicle information acquisition device 40. For example, the recognition unit 120 recognizes that the driver is operating the switches when an operation to turn the switches on/off or an operation to change the settings of the switches is being performed.

The determination unit 130 determines the driver's sensitivity to the discomfort felt by the driver with respect to braking control or drive control based on the driver's state. In this embodiment, the driver's sensitivity to the discomfort indicates the degree to which the driver feels discomfort with respect to braking control or drive control, that is, the acuteness of the sense of discomfort. The sensitivity is expressed, for example, by whether the sensitivity is low or high. The discomfort includes, for example, a sudden deceleration feeling in which the vehicle feels as if it is suddenly decelerating during braking control, and a poor acceleration feeling in which the vehicle feels as if it is not accelerating much during drive control. When braking control is autonomously performed by the driving assistance system 1 without the driver's operation, the driver may feel discomfort such as a sudden deceleration feeling in response to the deceleration of the vehicle. In addition, when the driving force is autonomously suppressed by the driving assistance system 1 during acceleration of the vehicle, the driver may feel discomfort such as a poor acceleration feeling in response to the acceleration of the vehicle.

The sensitivity changes depending on the driver's state. For example, when the driver is not concentrating on driving, such as when he or she is talking or operating switches, the driver will be less sensitive to discomfort than when the driver is concentrating on driving. In such cases, even if the braking and driving forces applied to the vehicle are the same, the driver is less likely to feel discomfort when the sensitivity is low than when the sensitivity is high. In other words, the sensitivity to discomfort is how easily the driver feels discomfort. The higher the sensitivity, the more likely the driver is to feel discomfort, and the lower the sensitivity, the less likely the driver is to feel discomfort.

In this embodiment, the judgment unit 130 judges whether a predetermined judgment condition is satisfied, and judges that the driver's sensitivity is low when the predetermined judgment condition is satisfied. Furthermore, the judgment unit 130 judges that the sensitivity is high when the predetermined judgment condition is not satisfied. For example, the predetermined judgment condition is that the driver's concentration on driving is low. That is, the judgment unit 130 judges that the driver's sensitivity is low when the driver's concentration on driving is low. Furthermore, the judgment unit 130 judges that the driver's sensitivity is high when the driver's concentration on driving is high. Note that in this embodiment, the predetermined judgment condition is not limited to the condition that the driver's concentration on driving is low, but may be a condition that either the driver is talking or the driver is operating switches is satisfied.

In addition, in this embodiment, when the determination unit 130 determines that the driver's sensitivity is low, the determination unit 130 stores the determination result that the sensitivity is low for a predetermined time period after the determination.

The calculation unit 140 calculates the braking/driving force to be applied to the vehicle according to the sensitivity of the driver to the discomfort of the driver to the braking/driving control of the vehicle. The braking force is the deceleration. When the calculation unit 140 determines that the sensitivity is low, it calculates a higher braking force than when it determines that the sensitivity is high. As an example of a method of calculating the braking force, a method using the change rate of the braking force will be described. The calculation unit 140 sets the change rate of the braking force high and calculates the braking force based on the change rate, thereby calculating a high braking force. The change rate of the braking force is the deceleration gradient. For example, when calculating a target deceleration to achieve the target vehicle speed of the vehicle, when the calculation unit 140 determines that the sensitivity is low, it sets the deceleration gradient used in the calculation higher than when it determines that the sensitivity is high. In addition, when the calculation unit 140 determines that the sensitivity is low, it may set the maximum value of the deceleration gradient set to avoid giving the driver discomfort higher than when it determines that the sensitivity is high.

The calculation unit 140 may also calculate a higher braking force by calculating a higher absolute value of the braking force. For example, when calculating a target deceleration to achieve the target vehicle speed of the vehicle, if the calculation unit 140 determines that the sensitivity is low, the calculation unit 140 may calculate a higher target deceleration than if the sensitivity is high. If the calculation unit 140 determines that the sensitivity is low, the calculation unit 140 may set the maximum deceleration higher than if the sensitivity is high in order to avoid giving the driver a sense of discomfort.

Figure 2 is a diagram showing the relationship between the deceleration gradient and the driver's discomfort. As shown in Figure 2, the larger the deceleration gradient, the more likely the driver is to feel discomfort in the braking control, i.e., a sense of sudden deceleration, and conversely, the smaller the deceleration gradient, the less likely the driver is to feel discomfort in the braking control. Also, when the driver is performing an action other than driving the vehicle, the driver is less likely to feel discomfort in the braking control. Therefore, even if the deceleration gradient is increased, the driver is less likely to feel discomfort in the braking control when the driver is performing an action other than driving the vehicle. Therefore, in this embodiment, when the driver is performing an action other than driving the vehicle and the driver is less likely to feel discomfort in the braking control, the deceleration gradient is increased and the vehicle braking control is executed.

Here, the setting of the deceleration gradient will be explained using FIG. 3A and FIG. 3B. FIG. 3A and FIG. 3B are diagrams showing graphs relating to the setting of the deceleration gradient [G/s]. In FIG. 3A and FIG. 3B, the solid line represents the corrected deceleration when the sensitivity is determined to be low, and the dashed line represents the reference deceleration when the sensitivity is determined to be high. In FIG. 3A, the corrected deceleration is the deceleration when the absolute value is the same as the absolute value of the reference deceleration and the deceleration gradient is higher than the deceleration gradient of the reference deceleration. Also, in FIG. 3B, the corrected deceleration is the deceleration when the absolute value is higher than the absolute value of the reference deceleration and the deceleration gradient is also higher than the deceleration gradient of the reference deceleration. As shown in FIG. 3A and FIG. 3B, the deceleration gradient of the corrected deceleration (solid line) from time t1 to a predetermined time is higher than the deceleration gradient of the reference deceleration (dashed line).

As described above, in this embodiment, by increasing the deceleration and executing braking control, the driving performance of the vehicle can be improved without causing the driver to feel uncomfortable, and the amount of correction operation by the driver can be reduced, thereby reducing the driving load. Generally, if the steering angle during turning is the same, when the vehicle speed is low, the turning radius is smaller than when the vehicle speed is high. In this embodiment, when the vehicle is turning, such as when the vehicle is traveling on a curved road, if the driver's sensitivity to discomfort is low, the deceleration is increased to slow down the vehicle, thereby improving the turning performance of the vehicle and reducing the turning radius. Furthermore, in this case, even if the deceleration is increased, the driver is less likely to feel uncomfortable because the driver's sensitivity to discomfort is low.

Next, a method of calculating the driving force will be described. The driving force is acceleration. When the calculation unit 140 determines that the sensitivity is low, it calculates a lower driving force than when it determines that the sensitivity is high. For example, the calculation unit 140 calculates a lower driving force by setting a low rate of change of the driving force and calculating the driving force based on the rate of change. The rate of change of the driving force is the acceleration gradient. When calculating a target acceleration for achieving the target vehicle speed of the vehicle, when the calculation unit 140 determines that the sensitivity is low, it sets the acceleration gradient used in the calculation to be smaller than when it determines that the sensitivity is high. Furthermore, when the calculation unit 140 determines that the sensitivity is low, it may set the maximum value of the acceleration gradient set to be lower than when it determines that the sensitivity is high in order to avoid giving the driver a sense of discomfort.

The smaller the acceleration gradient during drive control, the more likely the driver is to feel discomfort with the drive control, i.e., a sense of poor acceleration. Furthermore, when the driver is performing an action other than driving the vehicle, the driver is less likely to feel discomfort with the drive control. Therefore, when the driver is performing an action other than driving the vehicle, the driver is less likely to feel discomfort with the drive control even if the acceleration gradient is made small. Therefore, in this embodiment, when the driver is performing an action other than driving the vehicle and is less likely to feel discomfort with the drive control, the acceleration gradient is made large and the drive control of the vehicle is executed.

The calculation unit 140 may also calculate a lower driving force by calculating a lower absolute value of the driving force. For example, when calculating a target acceleration for achieving the target vehicle speed of the vehicle, if the calculation unit 140 determines that the sensitivity is low, it calculates a lower target acceleration than if the sensitivity is high. Also, if the calculation unit 140 determines that the sensitivity is low, it may set the maximum deceleration lower than if the sensitivity is high in order to avoid giving the driver a sense of discomfort.

As described above, in this embodiment, by executing drive control with low acceleration, the driving performance of the vehicle can be improved without causing discomfort to the driver, and the amount of correction operation by the driver can be reduced, thereby reducing the driving load. For example, even in a situation where the vehicle needs to accelerate when the vehicle is turning, such as when the vehicle is traveling on a curved road, if the driver's sensitivity to discomfort is low, the acceleration can be reduced to suppress the acceleration of the vehicle, thereby improving the turning performance of the vehicle and reducing the turning radius. Furthermore, in this case, even if the acceleration is low, the driver is less likely to feel discomfort because the driver's sensitivity to discomfort is low.

Figure 4 is a diagram showing the effect on vehicle performance of the presence or absence of braking/driving control when turning. In Figure 4, vehicle trajectories BT and CT represent the turning trajectory of the vehicle when the vehicle turns. Vehicle trajectory BT is the turning trajectory of the vehicle when the driver's sensitivity is low and braking control is performed at a higher deceleration. Vehicle trajectory CT is the turning trajectory of the vehicle when the driver's sensitivity is high and braking control is performed at a lower deceleration. Compared to when braking control is performed at a lower deceleration, when braking control is performed at a higher deceleration, the yaw rate of the vehicle becomes larger and the direction of the vehicle is more likely to change when turning. When comparing the yaw rate effects without braking/driving control, with braking/driving control, and with braking/driving control when the sensitivity of the sense of discomfort is judged under the condition that the vehicle enters from a straight-ahead state at the same vehicle speed and the same steering angle, if the sensitivity of the sense of discomfort is judged to be low and braking control is executed with a high deceleration, the braking control can have the effect of reducing the turning radius when turning, compared to braking control when the sensitivity of the sense of discomfort is not judged.

Here, a specific example of a method for calculating the driving and braking forces by the calculation unit 140 will be described. FIG. 5 is a block diagram of the calculation unit in FIG. 1. As shown in FIG. 5, the calculation unit 140 includes, as functional blocks, a vehicle behavior calculation unit 141, a target braking force calculation unit 142, a target driving force calculation unit 143, a corrected braking force calculation unit 144, and a corrected driving force calculation unit 145. Below, a situation in which the vehicle turns, such as when the vehicle is traveling on a curved road, will be described as an example. Note that in this embodiment, the braking and driving forces may be calculated not only when the vehicle is traveling on a curved road, but also when the vehicle is traveling straight ahead in situations where braking and driving control is required.

The vehicle behavior calculation unit 141 calculates the target vehicle behavior and estimated vehicle behavior during turning based on the vehicle speed, longitudinal acceleration, lateral acceleration, steering angle, accelerator operation information, and brake operation information acquired by the vehicle information acquisition device 40. The target vehicle behavior is represented by a target value to be realized in the vehicle state such as the current vehicle speed, i.e., an ideal value. The estimated vehicle behavior is represented by an estimated value calculated according to the vehicle state such as the current vehicle speed. The target vehicle behavior and estimated vehicle behavior during turning include, for example, a target yaw rate and an estimated yaw rate. The vehicle behavior calculation unit 141 calculates the estimated yaw rate based on a preset setting value related to turning characteristics that differ for each vehicle, the vehicle speed, and the steering angle. The turning characteristics are, for example, turning characteristics in a two-wheel model. The vehicle behavior calculation unit 141 also calculates the target yaw rate based on a preset target value related to turning characteristics that differ for each vehicle, the vehicle speed, and the steering angle.

The vehicle behavior calculation unit 141 also calculates an estimated acceleration based on accelerator operation information including the accelerator opening and the wheel end drive torque of the drive system. The estimated acceleration is an acceleration estimated from the driver's accelerator operation. The vehicle behavior calculation unit 141 also calculates an estimated deceleration based on brake operation information including the brake pressure and the wheel end regenerative torque of the drive system. The estimated deceleration is a deceleration estimated from the driver's brake operation.

The target braking force calculation unit 142 calculates a target braking force based on the target vehicle behavior calculated by the vehicle behavior calculation unit 141. The target braking force calculation unit 142 calculates a target braking force based on the target yaw rate calculated by the vehicle behavior calculation unit 141. Specifically, the target braking force calculation unit 142 calculates a target vehicle speed based on the target yaw rate and a target lateral acceleration set based on the turning characteristics of the vehicle, and calculates a vehicle speed difference between the vehicle speed acquired by the vehicle information acquisition device 40 and the target vehicle speed. The target braking force calculation unit 142 calculates a target braking force so that the vehicle speed difference with respect to the calculated target vehicle speed is eliminated. However, when the estimated acceleration is greater than a predetermined value, the vehicle is considered to be in an accelerating state, and the target braking force is calculated as 0.

When applying a braking force only to the wheels on the inside of the vehicle's turning to apply a yaw moment to the vehicle, the target braking force calculation unit 142 may calculate a target braking force to be applied to the wheels on the inside of the vehicle's turning based on the target yaw rate and estimated yaw rate calculated by the vehicle behavior calculation unit 141. Specifically, the target braking force calculation unit 142 calculates the yaw rate deviation between the target yaw rate and the estimated yaw rate. The target braking force calculation unit 142 calculates the target braking force so that the yaw rate deviation from the target yaw rate is eliminated.

In this embodiment, when the determination unit 130 determines that the sensitivity is high, the target braking force calculation unit 142 sets the maximum value of the target braking force and the maximum value of the gradient of the target braking force so as not to cause the driver to feel uncomfortable due to the braking control. When the calculated target braking force is higher than the maximum value, the target braking force calculation unit 142 calculates the maximum value as the target braking force.

The target driving force calculation unit 143 calculates the target driving force based on the target vehicle behavior calculated by the vehicle behavior calculation unit 141. The target driving force calculation unit 143 calculates the target driving force based on the target yaw rate calculated by the vehicle behavior calculation unit 141. Specifically, the target driving force calculation unit 143 calculates the target vehicle speed based on the target yaw rate and the target lateral acceleration set based on the turning characteristics of the vehicle, and calculates the vehicle speed difference between the vehicle speed acquired by the vehicle information acquisition device 40 and the target vehicle speed. The target driving force calculation unit 143 calculates the target driving force so that the vehicle speed difference with respect to the calculated target vehicle speed is eliminated. However, when the estimated deceleration is greater than a predetermined value, the vehicle is considered to be in a deceleration state, and the target driving force is calculated as 0.

In this embodiment, when the determination unit 130 determines that the sensitivity is high, the target driving force calculation unit 143 sets the maximum value of the target driving force and the maximum value of the gradient of the target driving force so as not to cause the driver to feel uncomfortable due to the drive control. When the calculated target driving force is higher than the maximum value, the target driving force calculation unit 143 calculates the maximum value as the target driving force.

The corrected braking force calculation unit 144 calculates the corrected braking force based on the result of the judgment in the judgment unit 130. If it is judged that the sensitivity is high, the corrected braking force calculation unit 144 calculates the corrected braking force as 0. On the other hand, if it is judged that the sensitivity is low, the corrected braking force calculation unit 144 sets the maximum value of the target braking force and the maximum value of the gradient of the target braking force higher than when it is judged that the sensitivity is high. In this case, the target braking force calculation unit 142 calculates the target braking force based on the maximum value of the target braking force and the maximum value of the gradient of the target braking force set by the corrected braking force calculation unit 144. The corrected braking force calculation unit 144 may also calculate the difference between the target braking force calculated by the target braking force calculation unit 142 and the maximum value of the target braking force as the corrected braking force.

The corrected driving force calculation unit 145 calculates the corrected driving force based on the result of the judgment in the judgment unit 130. If it is judged that the sensitivity is high, the corrected driving force calculation unit 145 calculates the corrected driving force as 0. On the other hand, if it is judged that the sensitivity is low, the corrected driving force calculation unit 145 sets the maximum value of the target driving force and the maximum value of the gradient of the target driving force lower than when it is judged that the sensitivity is high. In this case, the corrected driving force calculation unit 145 calculates the target driving force based on the set maximum value of the target driving force and the maximum value of the gradient of the target braking force. The target driving force calculated by the corrected driving force calculation unit 145 is referred to as the corrected driving force.

The braking device 220 obtains the target braking force calculated by the target braking force calculation unit 142 and the corrected braking force calculated by the corrected braking force calculation unit 144, and applies a braking force that is the sum of the target braking force and the corrected braking force to the wheels of the vehicle.

The drive device 230 applies the smaller driving force to the vehicle's wheels between the target driving force calculated by the target driving force calculation unit 143 and the corrected driving force calculated by the corrected driving force calculation unit 145.

Next, the processing procedure for executing the driving/braking force calculation method executed by the driving/braking force calculation device 100 will be described with reference to FIG. 6. FIG. 6 is a flow chart showing the processing procedure of the driving/braking force calculation method according to this embodiment. In this processing procedure, when the vehicle is traveling, the driving/braking force calculation device 100 starts the control flow from step S100.

First, in step S100, the braking/driving force calculation device 100 recognizes the state of the driver. The state of the driver is, for example, whether or not the driver is highly concentrated on driving the vehicle. In step S110, the braking/driving force calculation device 100 determines the sensitivity of the driver's discomfort based on the state of the driver. In step S120, the braking/driving force calculation device 100 calculates the braking/driving force according to the sensitivity of the discomfort. In the following explanation, the braking force and the driving force are collectively explained as the braking/driving force, but which of the braking force and the driving force is calculated is determined depending on whether braking control or driving control is required based on the target vehicle speed to be realized, etc. For example, when performing braking control, when the braking/driving force calculation device 100 determines that the sensitivity is low, it calculates a higher braking force than when it determines that the sensitivity is high. Also, when performing driving control, when the braking/driving force calculation device 100 determines that the sensitivity is low, it calculates a lower driving force than when it determines that the sensitivity is high.

Next, an example of the procedure for the driver state recognition process executed by the driving/braking force calculation device according to this embodiment will be described with reference to FIG. 7. FIG. 7 is a flowchart showing a subroutine executed in step S100 shown in FIG. 6. That is, FIG. 7 is a flowchart for explaining an example of the procedure for the driver state recognition process according to this embodiment.

In step S201, the braking/driving force calculation device 100 acquires information on the driver's conversation state, including voice information including conversations of the vehicle occupants and image information of the driver's face. In step S202, the braking/driving force calculation device 100 judges whether the driver is talking or not. For example, the braking/driving force calculation device 100 judges that the driver is talking when the occupants are talking and the driver's mouth is moving. If it is determined that the driver is talking, the braking/driving force calculation device 100 proceeds to step S205. If it is determined that the driver is not talking, the braking/driving force calculation device 100 proceeds to step S203. In step S203, the braking/driving force calculation device 100 acquires information on the operation state of the switches. In step S204, the braking/driving force calculation device 100 judges whether the driver is operating the switches or not. If it is determined that the driver is operating the switches, the braking/driving force calculation device 100 proceeds to step S205. If it is determined that the driver has not operated any switches, the braking/driving force calculation device 100 proceeds to step S206.

In step S205, the driving/braking force calculation device 100 recognizes the driver's state as being in a state of low concentration on driving. In step S206, the driving/braking force calculation device 100 recognizes the driver's state as being in a state of high concentration on driving. After recognizing the driver's state, the driving/braking force calculation device 100 returns to step S110 in FIG. 6.

Next, an example of the procedure of the determination process executed by the driving/braking force calculation device according to this embodiment will be described with reference to FIG. 8. FIG. 8 is a flowchart showing the subroutine executed in step S110 shown in FIG. 6. That is, FIG. 8 is a flowchart showing the process procedure for determining the sensitivity of discomfort in the driving/braking force calculation method according to this embodiment.

In step S207, the driving/braking force calculation device 100 determines whether the driver is in a state of high concentration. If it is determined that the driver is in a state of high concentration, the driving/braking force calculation device 100 proceeds to step S208. If it is determined that the driver is not in a state of high concentration, the driving/braking force calculation device 100 proceeds to step S209. In step S208, the driving/braking force calculation device 100 determines that the driver's sensitivity to discomfort is high. In step S209, the driving/braking force calculation device 100 determines that the driver's sensitivity to discomfort is low. After determining the sensitivity of the driver's discomfort, the driving/braking force calculation device 100 returns to S120 in FIG. 6.

As described above, the driving/braking force calculation method and driving/braking force calculation device according to this embodiment are a driving/braking force calculation method and device that calculate the braking force for braking a vehicle, acquire the state of the driver of the vehicle, determine the sensitivity indicating the degree to which the driver feels uncomfortable with the braking control based on the driver's state, and calculate a higher braking force if the sensitivity is determined to be low than if the sensitivity is determined to be high. This makes it possible to calculate the braking/braking force to be applied to the vehicle according to the driver's sensitivity to the discomfort felt by the driver with respect to the vehicle's braking/braking control.

Furthermore, when the braking/driving force calculation method and braking/driving force calculation device according to this embodiment determine that the sensitivity is low, the braking force change rate is set higher than when the sensitivity is determined to be high, and the braking force is calculated based on the change rate. As a result, when the sensitivity is determined to be low, a high braking force can be calculated using a high change rate.

Furthermore, when the braking/driving force calculation method and braking/driving force calculation device according to this embodiment determine that the sensitivity is low, they calculate a higher absolute value for the braking force than when they determine that the sensitivity is high. As a result, when the sensitivity is determined to be low, the absolute value of the braking force is increased, making it possible to calculate a higher braking force.

The driving and braking force calculation method and device according to this embodiment are a driving and braking force calculation method and device that calculate the braking force for braking a vehicle, and acquire the state of the driver of the vehicle, and determine the sensitivity indicating the degree to which the driver feels uncomfortable with the drive control based on the driver's state, and if the sensitivity is determined to be low, calculate a lower drive force than if the sensitivity is determined to be high. This makes it possible to calculate the driving and braking force to be applied to the vehicle according to the driver's sensitivity to discomfort with the vehicle's driving and braking control.

Furthermore, when the driving/braking force calculation method and driving/braking force calculation device according to this embodiment determine that the sensitivity is low, the driving force change rate is set lower than when the sensitivity is determined to be high, and the driving force is calculated based on the change rate. As a result, when the sensitivity is determined to be low, a lower change rate is used to calculate a higher driving force.

Furthermore, when the driving/braking force calculation method and driving/braking force calculation device according to this embodiment determine that the sensitivity is low, the absolute value of the driving force is calculated to be lower than when the sensitivity is determined to be high. As a result, when the sensitivity is determined to be low, the absolute value of the driving force is increased, making it possible to calculate a higher driving force.

The above-described embodiments are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

Reference Signs List 1: Driving assistance system 100: Braking/driving force calculation device 10: Processor 11: CPU
12...ROM
13...RAM
120: Recognition unit 130: Determination unit 140: Calculation unit 20: Voice recognition device 30: Vehicle-mounted camera 40: Vehicle information acquisition device 200: Vehicle controller 220: Braking device 230: Driving device 240: Steering device

Claims (8)

A braking/driving force calculation method for calculating a braking force for braking a vehicle, the method being executed by a braking/driving force calculation device,
The braking/driving force calculation device is
Acquire the state of the driver of the vehicle;
determining a sensitivity indicating a degree to which the driver feels uncomfortable with respect to braking control based on the state of the driver;
A driving/braking force calculation method, in which, when the sensitivity is determined to be low, the braking force is calculated to be higher than when the sensitivity is determined to be high. 2. The driving/braking force calculation method according to claim 1,
The braking/driving force calculation device is
When the sensitivity is determined to be low, the rate of change of the braking force is set higher than when the sensitivity is determined to be high;
A driving/braking force calculation method for calculating the braking force based on the rate of change. 2. The driving/braking force calculation method according to claim 1,
The braking/driving force calculation device is
When the sensitivity is determined to be low, the absolute value of the braking force is calculated to be higher than when the sensitivity is determined to be high. A braking/driving force calculation method for calculating a driving force for driving a vehicle, the method being executed by a braking/driving force calculation device,
The braking/driving force calculation device is
Acquire the state of the driver of the vehicle;
determining a sensitivity indicating a degree to which the driver feels uncomfortable with respect to drive control based on the state of the driver;
When the sensitivity is determined to be low, the driving force is calculated to be lower than when the sensitivity is determined to be high. 5. The driving/braking force calculation method according to claim 4,
The braking/driving force calculation device is
When the sensitivity is determined to be low, the rate of change of the driving force is set lower than when the sensitivity is determined to be high;
A driving/braking force calculation method for calculating the driving force based on the rate of change. 5. The driving/braking force calculation method according to claim 4,
The braking/driving force calculation device is
When the sensitivity is determined to be low, the absolute value of the driving force is calculated to be lower than when the sensitivity is determined to be high. A braking/driving force calculation device that calculates a braking force for braking a vehicle,
An acquisition unit that acquires a state of a driver of the vehicle;
a determination unit that determines a sensitivity indicating a degree to which the driver feels discomfort with respect to braking control based on a state of the driver;
a calculation unit that, when it is determined that the sensitivity is low, calculates the braking force to be higher than when it is determined that the sensitivity is high. A braking/driving force calculation device that calculates a driving force for driving a vehicle,
A recognition unit that recognizes a state of a driver of the vehicle;
a determination unit that determines a sensitivity indicating a degree to which the driver feels uncomfortable with respect to drive control based on a state of the driver;
a calculation unit that, when it is determined that the sensitivity is low, calculates the driving force to be lower than when it is determined that the sensitivity is high.

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