Driving assistance device, driving assistance method, and program

Abstract

To provide a driving support device, a driving support method, and a program capable of more efficiently prompting a driver to perform steering avoidance.SOLUTION: A driving support device comprises: a determination part which determines to prompt a driver of a movable body to avoid contact with an object detected by an object detection device whose detection range is at least on a traveling direction side of the movable body by steering, and a steering direction for avoiding the contact with the object; and a control part for guidance control to, when the determination part determines to prompt the driver of the movable body to avoid the contact with the object by steering, first cause an actuator capable of outputting force to a steering operator to execute outputting force to reach a first target force in the same direction as the steering direction in a first period to maintain the state, and then causing outputted force to reach zero in a second period longer than the first period.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a driving assistance device, a driving assistance method, and a program. [Background technology]

[0002] A conventional invention for a vehicle contact avoidance assistance device that assists in avoiding contact with an obstacle ahead has been disclosed (Patent Document 1). This device includes a steering device that has a steering actuator for steering the vehicle's steered wheels and turns the steered wheels in response to steering wheel operation, a relative position acquisition sensor that acquires the relative position of the obstacle with respect to the vehicle, a control device that determines whether driving operation assistance for contact avoidance is necessary based on the relative position and that is configured to execute steering control that controls the steering amount of the steering actuator so as to avoid contact with the obstacle when it determines that driving operation assistance is necessary, and a grip state detection sensor that detects the driver's grip state on the steering wheel, and the control device has a normal mode and a limited mode as control modes for executing the steering control, and selectively executes steering control in the limited mode based on the grip state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-62804 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described conventional technology, notification control is performed so that the steering speed in the same direction as the steering direction in the steering control is greater than the steering speed in the opposite direction to the steering direction in the steering control, but it is not specifically made clear how much the steering speed should be increased.

[0005] The present invention has been made in consideration of the above circumstances, and one of its objects is to provide a driving assistance device, a driving assistance method, and a program that can more effectively prompt the driver to steer to avoid an accident. [Means for solving the problem]

[0006] A driving assistance device, a driving assistance method, and a program according to the present invention employ the following configuration. (1): A driving assistance device according to one embodiment of the present invention includes a decision unit that prompts a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the direction of travel of the moving body by steering, and that determines a steering direction to avoid contact with the object; and a control unit that, when the decision unit determines to prompt the driver of the moving body to avoid contact with the object by steering, performs guidance control by causing an actuator that can output a force to a steering operator to first output a force so that a first target force in the same direction as the steering direction is reached within a first period of time and maintained in that state, and then causes the output force to reach zero within a second period of time that is longer than the first period of time.

[0007] (2): In the above aspect (1), the first period is a period of 1 / 4 or less of the reciprocal of 5 Hz and 1 / 4 or more of the reciprocal of 30 Hz, and the second period is a period of 1 / 4 or more of the reciprocal of 4 Hz.

[0008] (3): In the above-mentioned aspect (1) or (2), the steering device mounted on the moving body is one in which the steering operator and the steering wheel are mechanically connected, and the control unit, in the induction control, causes the force output by the actuator to reach zero in the second period, and then causes the actuator to output a force to reach a second target force in the opposite direction to the steering direction in a third period longer than the first period, maintaining that state, and then causes the force output to reach zero in a fourth period.

[0009] (4): In the above aspect (3), the control unit equalizes the integral value of the force that the actuator is caused to output in the guidance control in the same direction as the steering direction with the integral value of the force that the actuator is caused to output in the guidance control in the opposite direction to the steering direction.

[0010] (5): In the above aspect (3), the third period is equal to the first period.

[0011] (6): In another aspect of the driving assistance method of the present invention, a driving assistance device prompts a driver of a moving body to avoid contact with an object detected by an object detection device whose detection range is at least in the direction of travel of the moving body by steering, and determines a steering direction to avoid contact with the object. When it is determined that the driver of the moving body should avoid contact with the object by steering, an actuator capable of outputting force to a steering operator first outputs a force to reach a first target force in the same direction as the steering direction within a first period of time and maintains that state, and then causes the output force to reach zero within a second period of time that is longer than the first period of time. Driving assistance methods.

[0012] (7): Another aspect of the present invention provides a program for causing a processor of a driving assistance device to prompt a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the direction of travel of the moving body by steering, determine a steering direction to avoid contact with the object, and, when it is determined that the driver of the moving body should be prompted to avoid contact with the object by steering, cause an actuator capable of outputting a force to a steering operator to first output a force so that a first target force in the same direction as the steering direction is reached within a first period of time and maintain that state, and then cause the output force to reach zero within a second period of time that is longer than the first period of time. [Effects of the Invention]

[0013] According to the aspects (1) to (7), the driver can be more effectively prompted to steer to avoid the collision. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a configuration diagram mainly showing a driving assistance device 100 according to a first embodiment. [Figure 2] FIG. 2 is a configuration diagram of a steering device 220. [Figure 3] FIG. 10 is a diagram showing an overview of the risks set by the transportation participant behavior prediction unit 120. [Figure 4] 10 is a diagram for explaining the control of the actuator 226 by the guidance control unit 160 and the effect on the driver. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, with reference to the drawings, embodiments of a driving assistance device, a driving assistance method, and a program of the present invention will be described. The driving assistance device is a device that assists in driving a mobile object. A "mobile object" refers to a structure that can move by its own drive mechanism, such as a vehicle, a micromobile, an autonomous mobile robot, a ship, or a drone. In the following explanation, it is assumed that the mobile object is a vehicle that moves on the ground, and the configuration and functions for moving the vehicle on the ground will be described.

[0016] First Embodiment FIG. 1 is a configuration diagram mainly showing a driving assistance device 100 according to the first embodiment. The driving assistance device 100 is mounted on a vehicle. In addition to the driving assistance device 100, this vehicle (hereinafter referred to as vehicle M) is also equipped with components such as an object detection device 10, a vehicle sensor 40, a braking device 200, and a steering device 220. Note that the configuration shown in FIG. 1 is merely an example, and some of the components may be omitted, or other components may be added. The vehicle M is equipped with driving force output devices such as an engine and a traction motor, but these will not be shown or described.

[0017] The object detection device 10 may include some or all of a camera, a radar device, a LIDAR (Light Detection and Ranging), a sensor fusion device, etc. The object detection device 10 is a device for detecting objects within a detection range at least in the traveling direction of the vehicle M. The camera is, for example, a digital camera using a solid-state image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The camera may be attached to any location on the vehicle M. When capturing images of the front, the camera may be attached to the top of the front windshield or the back of the rearview mirror. The camera may, for example, periodically capture images of the surroundings of the vehicle M. The camera may be a stereo camera or a distance sensor. The radar device emits radio waves such as millimeter waves around the vehicle M and detects radio waves reflected by the object (reflected waves) to detect at least the position (distance and direction) of the object. The radar device may detect the position and speed of the object using a frequency-modulated continuous wave (FM-CW) method. The LIDAR irradiates the periphery of the vehicle M with light (or electromagnetic waves with wavelengths similar to light) and measures the scattered light. The LIDAR detects the distance to an object based on the time between light emission and reception. The irradiated light is, for example, pulsed laser light. The sensor fusion device performs sensor fusion processing on the detection results from some or all of the camera, radar device, and LIDAR to recognize the position, type, speed, etc. of the object. The object detection device 10 may be equipped with an image analysis device that exclusively analyzes camera images instead of the sensor fusion device. This image analysis device may be a function of the driving assistance device 100. The object detection device 10 outputs the recognition results to the driving assistance device 100.

[0018] The vehicle sensor 40 includes a vehicle speed sensor that detects the speed of the vehicle M, an acceleration sensor that detects the acceleration, a yaw rate sensor that detects the angular velocity around a vertical axis, a direction sensor that detects the direction of the vehicle M, and the like.

[0019] Prior to describing the driving assistance device 100, the braking device 200 and the steering device 220 will be described.

[0020] The braking device 200 includes, for example, a brake caliper, a cylinder that transmits hydraulic pressure to the brake caliper, an electric motor that generates hydraulic pressure in the cylinder, and a brake ECU. The brake ECU controls the electric motor according to information input from the driving assistance device 100 or information input from a driving operator (not shown), so that a brake torque corresponding to the braking operation is output to each wheel. The braking device 200 may include a backup mechanism that transmits hydraulic pressure generated by operation of the brake pedal to the cylinder via a master cylinder. Note that the braking device 200 is not limited to the configuration described above, and may also be an electronically controlled hydraulic braking device that transmits hydraulic pressure from a master cylinder to the cylinder.

[0021] 2 is a configuration diagram of steering device 220. Steering device 220 includes, for example, a steering operator 222, a torque sensor 224, an actuator 226, a steering angle sensor 228, and a steering wheel 230. These components are mechanically connected by a connecting unit 232 that includes a steering shaft, a gear mechanism, etc. Note that connecting unit 232 may have a function for temporarily releasing the connection, etc. Steering device 220 also includes a steering ECU (Electronic Control Unit) 240. Note that steering device 220 may be a so-called steer-by-wire steering device in which there is no mechanical connection between steering operator 222 and steering wheel 230.

[0022] The steering operator 222 is, for example, a steering wheel. Alternatively, the steering operator 222 may be a special steering wheel, a joystick, a lever, a cross key, or another steering operator. In the following description, the steering operator 222 is assumed to be a steering wheel. When the steering operator 222 is rotated, it transmits a rotational force (hereinafter referred to as torque. If the steering operation is not a rotational operation, the "force" in the present invention is not limited to torque) to the connecting portion 232. At least a portion of the connecting portion 232 operates as a rotation shaft. The torque sensor 224 detects the torque applied to the steering operator 222 and outputs it to the steering ECU 240. The actuator 226 is, for example, a motor, whose stator is connected to the vehicle body and whose rotor rotates together with the connecting portion 232. The actuator 226 outputs a force to the connecting portion in response to an instruction from the steering ECU 240, thereby achieving a so-called power steering function. When actuator 226 outputs torque to coupling portion 232, the torque is also transmitted to steering operator 222. When actuator 226 outputs a small torque, a vibration is transmitted to the hand of the driver of vehicle M, providing some kind of awareness. Actuator 226 may also operate to apply a reaction force to the torque applied to steering operator 222, thereby suppressing the steering operation. This realizes driving assistance such as LKAS (Lane Keeping Assist System). Although the actuator for realizing the power steering function and the actuator for outputting the reaction force may be provided separately, they are represented here as one entity. Steering angle sensor 228 detects the rotation angle (steering angle) of steered wheels 230 and outputs the detected value to steering ECU 240. Steering ECU 240 operates actuator 226 based on information input from torque sensor 224 and steering angle sensor 228, or in response to an instruction from driving assistance device 100.

[0023] Returning to FIG. 1 , the driving assistance device 100 includes, for example, a recognition unit 110, a traffic participant behavior prediction unit 120, a trajectory prediction unit 130, a determination unit 140, an emergency stop control unit 150, and a guidance control unit 160. These components are realized by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Furthermore, some or all of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device (a storage device with a non-transitory storage medium) such as the HDD or flash memory of the driving assistance device 100, or may be stored in a removable storage medium such as a DVD or CD-ROM, and installed in the HDD or flash memory of the driving assistance device 100 by inserting the storage medium (non-transitory storage medium) into a drive device.

[0024] The recognition unit 110 recognizes the type, position, speed, acceleration, etc. of objects around the vehicle M based on information input from the object detection device 10. The position of an object is recognized as a position on an absolute coordinate system with a representative point of the vehicle M (such as the center of gravity or the center of the drive shaft) as the origin, and is used for control. The position of an object may be expressed by a representative point such as the center of gravity or a corner of the object, or by a represented area. The "state" of an object may include the acceleration or jerk of the object, or its "behavioral state" (for example, whether or not the vehicle is changing lanes or is about to change lanes). In this way, the recognition unit 110 recognizes objects that are present at least in the traveling direction of the vehicle M and that the vehicle M should avoid contacting.

[0025] Furthermore, the recognition unit 110 recognizes, for example, the lane in which the vehicle M is traveling (driving lane). For example, the recognition unit 110 recognizes the position and attitude of the vehicle M relative to the driving lane. For example, the recognition unit 110 may recognize, as the relative position and attitude of the vehicle M relative to the driving lane, the deviation of the reference point of the vehicle M from the center of the lane and the angle it forms with a line connecting the centers of the lanes in the direction of travel of the vehicle M. Alternatively, the recognition unit 110 may recognize, as the relative position of the vehicle M relative to the driving lane, the position of the reference point of the vehicle M relative to either side edge of the driving lane (a road dividing line or a road boundary).

[0026] The traffic participant behavior prediction unit 120 predicts the future behavior of a moving entity (traffic participant) that exists in the driving lane or an adjacent lane adjacent to the driving lane among the objects recognized by the recognition unit 110. Traffic participants include other vehicles, pedestrians, bicycles, etc. For example, the traffic participant behavior prediction unit 120 may predict the future behavior of the traffic participant based on the traffic participant's past movement history under assumptions such as constant speed and constant acceleration, or may predict the future behavior of the traffic participant using a method such as a Kalman filter. Furthermore, the traffic participant's future behavior may be predicted taking into account the direction of the traffic participant (the direction of the vehicle axis in the case of a vehicle, or the direction of the face in the case of a pedestrian). The future behavior means, for example, the position of the traffic participant at multiple future points in time.

[0027] Furthermore, the traffic participant behavior prediction unit 120 may set risk, which is an index value indicating the degree to which vehicle M should not enter or approach, on an assumed plane S, which represents the space around vehicle M as a two-dimensional plane viewed from above, based on the predicted future behavior of traffic participants. In other words, risk indicates the probability of the presence of objects (including not only traffic participants but also impassable areas such as road shoulders, guardrails, and areas outside white lines) (it does not have to be a "probability" in the strict sense). A higher risk value indicates that vehicle M should not enter or approach, and a value closer to zero indicates that it is more favorable for vehicle M to travel. However, this relationship may be reversed.

[0028] The traffic participant behavior prediction unit 120 also sets risks on the assumed plane S for future points in time specified at regular time intervals, such as the current time t, after Δt (time t + Δt), after 2Δt (time t + 2Δt), etc.

[0029] FIG. 3 is a diagram illustrating an overview of the risks set by the traffic participant behavior prediction unit 120. The traffic participant behavior prediction unit 120 sets risks for traffic participants on an assumed plane S, with contour lines representing ellipses or circles based on the direction of travel and speed, and sets a fixed value of risk for impassable areas. In the figure, R(M1) is the risk of stopped vehicle M1, and R(P) is the risk of pedestrian P. Because pedestrian P is moving in a direction crossing the road, a risk is set at a position different from the current time for each future point in time. The same applies to moving vehicles, bicycles, etc. R(BD) is the risk of impassable areas BD. In the figure, the density of the hatching indicates the risk value, with darker hatching indicating a higher risk. The traffic participant behavior prediction unit 120 may set risks such that the value increases the further away from the center of the lane. The traffic participant behavior prediction unit 120 may not set such risks, but simply predict the positions of traffic participants at multiple future points in time.

[0030] The trajectory prediction unit 130 inputs the speed VM of the vehicle M detected by the vehicle speed sensor included in the vehicle sensor 40 and the steering angle θM of the vehicle M detected by the steering angle sensor 228 of the steering device 220 into a vehicle body model (an arc model, a two-wheel model, etc.) and predicts the trajectory of the vehicle M for a certain period of time in the future. Various methods are known for the vehicle body model, so a detailed description will be omitted.

[0031] The determination unit 140 refers to the processing results of the traffic participant behavior prediction unit 120 and the trajectory prediction unit 130 and determines whether it is difficult to avoid contact with the object recognized by the recognition unit 110 by steering (steering avoidance). For example, the determination unit 140 determines that steering avoidance is difficult if the TTC (Time To Collision) with the object is equal to or less than a threshold, or if the lateral acceleration during the avoidance action exceeds an upper limit when an avoidance trajectory that can avoid contact is generated. If it is determined that steering avoidance is difficult, the determination unit 140 activates the emergency stop control unit 150. In response, the emergency stop control unit 150 instructs the brake device 200 to stop the vehicle M.

[0032] If it is determined that steering to avoid the obstacle is not difficult, the determination unit 140 prompts the driver of the vehicle M to steer to avoid the obstacle and determines the steering direction (in which direction to steer). Regarding the steering direction, the determination unit 140 may determine it based on whether the object to be avoided is on the left or right side of the trajectory of the vehicle M predicted by the trajectory prediction unit 130, or may determine it by further taking into account the lateral position at which the vehicle M is moving within the lane. There are no particular restrictions on the method for determining the steering direction, and the steering direction may be determined by any method.

[0033] When the decision unit 140 decides to prompt the driver to avoid contact with the object by steering, the guidance control unit 160 performs guidance control to control the actuator 226 via the steering ECU 240 as follows.

[0034] 4 is a diagram for explaining the control of actuator 226 by guidance control unit 160 and the effect it has on the driver. In the following explanation, the direction of operation of steering operator 222 is defined as positive when it is the same as the steering direction, and negative when it is the opposite direction to the steering direction.

[0035] First, the guidance control unit 160 controls the actuator 226 to output torque while gradually increasing it so that the torque reaches a first target torque T1 in the same direction as the steering direction (i.e., positive in the figure) within a first period P1, and when the torque reaches the first target torque T1, the guidance control unit 160 controls the actuator 226 to maintain the torque for a first maintenance period Pm1.

[0036] Next, the guidance control unit 160 controls the actuator 226 so that the torque reaches zero in a second period P2 that is longer than the first period P1.

[0037] Next, the guidance control unit 160 controls the actuator 226 so that the second target torque T2 in the direction opposite to the steering direction is reached within the third period P3, and once the torque reaches the second target torque T2, the guidance control unit 160 controls the actuator 226 so that the torque is maintained for the second maintenance period Pm2.

[0038] Next, the guidance control unit 160 controls the actuator 226 so that the torque is gradually weakened and reaches zero in a fourth period P4.

[0039] Here, the first period P1 is, for example, a period equal to or shorter than a quarter wavelength of 5 Hz (a quarter of the reciprocal of 5 Hz) and equal to or longer than a quarter wavelength of 30 Hz (a quarter of the reciprocal of 30 Hz). In other words, the first period P1 is a period equal to or longer than 0.0083 seconds and equal to or shorter than 0.05 seconds. Here, it has been found that the resonant frequency of a human upper arm is between 5 and 30 Hz. By defining the first period P1 as described above, the torque output during the first period P1 constitutes part of the wave of the resonant frequency of the human upper arm, and is therefore expected to cause resonance in the driver's arm.

[0040] On the other hand, the second period P2 is, for example, a period equal to or longer than a quarter wavelength of 4 Hz (quarter of the reciprocal of 4 hertz). In other words, the second period P2 is a period equal to or longer than 0.0675 seconds. Because the range of 4 Hz or less is outside the range of the resonant frequency of a person's upper arm, it is expected that the torque output during the second period P2 will not cause resonance in the driver's arm.

[0041] Although the figure shows the rate of change of torque as being the same in the second period P2 and the third period P3, they may be different. For example, the induction control unit 160 may control the actuator 226 so that the rate of change of torque gradually becomes gentler in the third period P3. Even in this case, it is desirable for the torque to change smoothly throughout the second period P2 and the third period P3 so that no inflection point occurs in the torque.

[0042] The fourth period P4 may be the same as or different from the first period P1. By making the fourth period P4 equal to the first period P1, resonance may occur in the driver's arm during the fourth period P4 of torque loss. The fourth period P4 may be approximately the same length as the third period P3.

[0043] This makes it possible to make the driver more aware of the steering direction, but less aware of the opposite direction. The induction control unit 160 may set the first target torque T1, the second target torque T2, and the various periods described above so that the integral value of the positive torque and the integral value of the negative torque are equal. This makes it possible to prevent the vehicle M from making unnecessary turns due to induction control, particularly in a steering device that has a mechanical connection between the steering operator and the steering wheels. As a result, it is possible to more effectively encourage the driver to steer to avoid collisions while maintaining the feeling of manual driving. There are no particular restrictions on the magnitude relationship between the first target torque T1 and the second target torque T2. They may be the same value or different values.

[0044] If the steering device 220 is a steer-by-wire steering device, the output of torque in the third period P3 and the fourth period P4 may be omitted. In other words, the guidance control may be terminated when the torque of the actuator 226 is set to zero after the second period P2 has elapsed. This is because in a steer-by-wire steering device, even if torque is output to the steering operator, it is possible to prevent the torque from being transmitted to the steered wheels.

[0045] According to the embodiment described above, the actuator 226 first outputs a force to reach the first target torque T1 in the same direction as the steering direction within the first period P1, and maintains that state, and then causes the output force to reach zero within the second period P2, which is longer than the first period P1, thereby more effectively urging the driver to steer to avoid the collision.

[0046] The driving assistance device may not have an emergency stop processing unit and may perform only avoidance trajectory generation and guidance control. Also, the driving assistance device may be configured as part of an automatic driving control device (which operates exclusively during manual driving periods).

[0047] The above-described embodiment can be expressed as follows. a storage medium for storing computer-readable instructions; a processor connected to the storage medium; The processor executes the computer-readable instructions to: prompting a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the traveling direction of the moving body, by steering, and determining a steering direction for avoiding contact with the object; When it is determined that the driver of the moving body should be prompted to avoid contact with the object by steering, an actuator capable of outputting a force to a steering operator is configured to: First, a force is output so that a first target force in the same direction as the steering direction is reached within a first period, and the state is maintained; Then, in a second period longer than the first period, the output force is allowed to reach zero. Driving assistance device.

[0048] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0049] 10. Object detection device 40 Vehicle Sensors 100 Driving assistance device 110 Recognition part 120 Traffic Participant Behavior Prediction Department 130 Trajectory Prediction Unit 140 Decision Section 150 Emergency stop processing unit 160 Guidance control unit 200 Brake equipment 220 Steering Gear 226 Actuator

Claims

1. a determination unit that prompts a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the traveling direction of the moving body, by steering the vehicle, and determines a steering direction for avoiding contact with the object; When the determination unit determines to prompt the driver of the moving body to avoid contact with the object by steering, the actuator capable of outputting a force to a steering operator First, a force is output so as to reach a first target force in the same direction as the steering direction within a first period, and the state is maintained; Then, the output force is allowed to reach zero in a second period longer than the first period. A control unit that performs guidance control, the first period is a period of not more than ¼ of the reciprocal of 5 Hz and not less than ¼ of the reciprocal of 30 Hz, the second period is equal to or greater than 1 / 4 of the reciprocal of 4 hertz; Driving assistance device.

2. a determination unit that prompts a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the traveling direction of the moving body, by steering the vehicle, and determines a steering direction for avoiding contact with the object; When the determination unit determines to prompt the driver of the moving body to avoid contact with the object by steering, the actuator capable of outputting a force to a steering operator First, a force is output so as to reach a first target force in the same direction as the steering direction within a first period, and the state is maintained; Then, the output force is allowed to reach zero in a second period longer than the first period. A control unit that performs guidance control, The steering device mounted on the moving body is configured such that the steering operator and the steering wheel are mechanically connected to each other, The control unit, in the guidance control, After the force output by the actuator reaches zero during the second period, the actuator outputs a force in a third period longer than the first period so as to reach a second target force in the opposite direction to the steering direction, and maintains that state; Then, in the fourth period, the output power reaches zero. Driving assistance device.

3. the control unit equalizes an integral value of the force that the actuator is caused to output in the guidance control in the same direction as the steering direction with an integral value of the force that the actuator is caused to output in the guidance control in the opposite direction to the steering direction. The driving assistance device according to claim 2.

4. the fourth period is equal to the first period; The driving assistance device according to claim 2.

5. Driving assistance devices, prompting a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the traveling direction of the moving body, by steering, and determining a steering direction for avoiding contact with the object; When it is determined that the driver of the moving body should be prompted to avoid contact with the object by steering, an actuator capable of outputting a force to a steering operator is configured to: First, a force is output so as to reach a first target force in the same direction as the steering direction within a first period, and the state is maintained; Then, the output force is allowed to reach zero in a second period longer than the first period, the first period is a period of not more than ¼ of the reciprocal of 5 Hz and not less than ¼ of the reciprocal of 30 Hz, the second period is equal to or greater than 1 / 4 of the reciprocal of 4 hertz; Driving assistance methods.

6. The processor of the driving assistance device prompting a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the traveling direction of the moving body, by steering the vehicle; and determining a steering direction for avoiding contact with the object; When it is determined that the driver of the moving body should be prompted to avoid contact with the object by steering, an actuator capable of outputting a force to a steering operator is configured to: First, a force is output so as to reach a first target force in the same direction as the steering direction within a first period, and the state is maintained; and then causing the output force to reach zero in a second period longer than the first period; the first period is a period of not more than ¼ of the reciprocal of 5 Hz and not less than ¼ of the reciprocal of 30 Hz, the second period is equal to or greater than 1 / 4 of the reciprocal of 4 hertz; program.

7. Driving assistance devices, prompting a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the traveling direction of the moving body, by steering, and determining a steering direction for avoiding contact with the object; When it is determined that the driver of the moving body should be prompted to avoid contact with the object by steering, an actuator capable of outputting a force to a steering operator is configured to: First, a force is output so as to reach a first target force in the same direction as the steering direction within a first period, and the state is maintained; Then, the output force is allowed to reach zero in a second period longer than the first period, The steering device mounted on the moving body is configured such that the steering operator and the steering wheel are mechanically connected to each other, After the force output by the actuator reaches zero during the second period, the actuator outputs a force in a third period longer than the first period so as to reach a second target force in the opposite direction to the steering direction, and maintains that state; Then, in the fourth period, the output power reaches zero. Driving assistance methods.

8. The processor of the driving assistance device prompting a driver of the moving body to avoid contact with an object detected by an object detection device having a detection range at least in the traveling direction of the moving body, by steering the vehicle; and determining a steering direction for avoiding contact with the object; When it is determined that the driver of the moving body should be prompted to avoid contact with the object by steering, an actuator capable of outputting a force to a steering operator is configured to: First, a force is output so as to reach a first target force in the same direction as the steering direction within a first period, and the state is maintained; Then, the output force reaches zero in a second period longer than the first period. The steering device mounted on the moving body is configured such that the steering operator and the steering wheel are mechanically connected to each other, After the force output by the actuator reaches zero during the second period, the actuator outputs a force in a third period longer than the first period so as to reach a second target force in the opposite direction to the steering direction, and maintains that state; Then, in a fourth period, the output force is made to reach zero. program.

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