Parking assistance device, parking assistance method, and recording medium

Abstract

The present invention provides a parking assistance device which, in parking assistance, does not cause an unwanted sudden acceleration when the selected required driving force changes from a second required driving force for reducing damage caused by a collision of a vehicle to a first required driving force for parking assistance. The parking assistance device includes a first required driving force generation unit and a mediation unit. The mediation unit obtains the second required driving force from the second required driving force generation unit, compares the first required driving force and the second required driving force, and outputs the smaller one to the driving force generation control unit. Moreover, when the mediation unit selects the second required driving force, the first required driving force generation unit performs at least any one of a first control that does not increase the first required driving force until the next time the mediation unit selects the first required driving force, and a second control that recalculates the first required driving force based on the actual speed at that time when the mediation unit selects the first required driving force next time.

Description

Technical Field

[0001] Embodiments of the present invention relate to a parking assistance device, a parking assistance method, and a recording medium. Background Art

[0002] Conventionally, in vehicle parking assistance technology, for example, in order to control the vehicle speed, the first required driving force for parking assistance and the second required driving force for reducing damage caused by a vehicle collision are calculated in parallel. In this case, the smaller of the first required driving force and the second required driving force is selected.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2013 - 248925

[0004] In the above prior art, there is a case where an undesired sudden acceleration occurs when the selected required driving force changes from the second required driving force to the first required driving force, and there is room for improvement in this regard. Summary of the Invention

[0005] The parking assistance device according to the embodiment includes: a first required driving force generation unit that calculates a target traveling speed of the vehicle when the vehicle is to park, and generates a first required driving force based on the target traveling speed and the actual speed of the vehicle; and a mediation unit that obtains the second required driving force from a second required driving force generation unit that generates the second required driving force to reduce damage caused by a collision of the vehicle, compares the first required driving force and the second required driving force, and selects the smaller one to output to a driving force generation control unit. Further, when the mediation unit selects the second required driving force, the first required driving force generation unit performs at least any one of a first control and a second control. In the first control, the first required driving force is not increased until the mediation unit selects the first required driving force next. In the second control, when the mediation unit selects the first required driving force next, the first required driving force is recalculated based on the actual speed when the mediation unit selects the first required driving force. According to this configuration, for example, even when the second required driving force is selected, by performing at least any one of the above first control and second control, it is possible to avoid undesired sudden acceleration when the required driving force selected later changes from the second required driving force to the first required driving force.

[0006] In addition, in the parking assistance device according to the embodiment, when the mediation unit selects the second required driving force and the vehicle wants to start from a stopped state, the first required driving force generation unit performs the first control. According to this configuration, for example, when the vehicle starts from a stopped state, it is possible to avoid undesired sudden acceleration.

[0007] In addition, in the parking assist device according to the embodiment, when the second required driving force is selected by the mediation unit and the vehicle is in the process of traveling, the first required driving force generation unit executes the second control. According to this configuration, for example, when the vehicle is in the process of traveling, an unexpected sudden acceleration can be avoided.

[0008] In addition, in the parking assist device according to the embodiment, the first required driving force generation unit further executes a height difference control for increasing the first required driving force when the vehicle crosses a height difference. When the second required driving force is selected by the mediation unit and the vehicle crosses a height difference, the first required driving force generation unit stops the height difference control until the first required driving force is selected by the mediation unit next. According to this configuration, for example, an unexpected sudden acceleration caused by the height difference control of the vehicle can be avoided.

[0009] In addition, the parking assist method according to the embodiment includes: a first required driving force generation step in which, when the vehicle is to stop, a target traveling speed of the vehicle is calculated, and a first required driving force is generated based on the target traveling speed and the actual speed of the vehicle; and a mediation step in which the second required driving force is obtained from a second required driving force generation unit that generates a second required driving force to reduce damage caused by a collision of the vehicle, the first required driving force and the second required driving force are compared, and the smaller one is selected and output to a driving force generation control unit. Moreover, when the second required driving force is selected in the mediation step, at least any one of a first control and a second control is executed in the first required driving force generation step. In the first control, the first required driving force is not increased until the first required driving force is selected in the mediation step next. In the second control, when the first required driving force is selected in the mediation step next, the first required driving force is recalculated based on the actual speed when the first required driving force is selected in the mediation step. According to this configuration, for example, even when the second required driving force is selected, by executing at least any one of the above first control and second control, it is possible to avoid an unexpected sudden acceleration when the required driving force selected later changes from the second required driving force to the first required driving force.

[0010] In addition, a recording medium of an embodiment stores a parking assistance program for causing a computer to execute the following steps: a first required driving force generation step in which, when the vehicle is to stop, a target traveling speed of the vehicle is calculated and a first required driving force is generated based on the target traveling speed and the actual speed of the vehicle; and a mediation step in which the second required driving force generated by a second required driving force generation unit for reducing damage caused by a collision of the vehicle is obtained, the first required driving force and the second required driving force are compared, and the smaller one is selected and output to a driving force generation control unit. Further, when the second required driving force is selected in the mediation step, at least one of a first control and a second control is executed in the first required driving force generation step. In the first control, the first required driving force is not increased until the first required driving force is selected in the next mediation step. In the second control, when the first required driving force is selected in the next mediation step, the first required driving force is recalculated based on the actual speed when the first required driving force is selected in the mediation step. According to this configuration, for example, even when the second required driving force is selected, by executing at least one of the above-described first control and second control, it is possible to avoid an undesired sudden acceleration when the required driving force selected later changes from the second required driving force to the first required driving force. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 FIG. 6 is an exemplary perspective view showing a state in which a part of a vehicle compartment of an embodiment is seen through.

[0012] Figure 2 FIG. 10 is an exemplary top view (bird's-eye view) of a vehicle according to an embodiment.

[0013] Figure 3 FIG. 14 is a view showing an example of an instrument panel of a vehicle according to an embodiment as viewed from the rear of the vehicle.

[0014] Figure 4 FIG. 18 is an exemplary block diagram showing a configuration of a parking assistance system according to an embodiment.

[0015] Figure 5 FIG. 22 is an exemplary block diagram showing a functional configuration of an ECU of a parking assistance system according to an embodiment.

[0016] Figure 6 FIG. 26 is an exemplary flowchart showing a start-up process of a first required driving force generation unit in an ECU of a parking assistance system according to an embodiment.

[0017] Figure 7It is a timing chart illustratively showing the changes over time of various parameters when the vehicle starts in the comparative example and the embodiment.

[0018] Figure 8 It is a timing chart illustratively showing the changes over time of correction amounts and the like during the vehicle driving in the comparative example and the embodiment.

[0019] Figure 9 It is an illustrative flowchart of the processing during driving of the first required driving force generation unit in the ECU of the parking assistance system of the embodiment.

[0020] Figure 10 It is a timing chart illustratively showing the changes over time of various parameters during the vehicle driving in the comparative example and the embodiment.

[0021] Explanation of reference numerals: 1... vehicle, 14... ECU, 100... parking assistance system, 141... first required driving force generation unit, 142... second required driving force generation unit, 143... mediation unit, 144... driving force generation control unit. Detailed Embodiment

[0022] Hereinafter, illustrative embodiments of the parking assistance device, parking assistance method, and parking assistance program of the present invention will be disclosed. The configurations of the embodiments shown below, and the actions, results, and effects brought about by these configurations are examples. The present invention can also be implemented by configurations other than those disclosed in the following embodiments, and can obtain at least one of various effects and derivative effects based on the basic configuration.

[0023] The vehicle 1 of the present embodiment can be, for example, an internal combustion engine vehicle that uses an unillustrated internal combustion engine as a drive source, that is, an internal combustion engine vehicle, an electric vehicle that uses an unillustrated electric motor as a drive source, that is, an electric vehicle or a fuel cell vehicle, etc., a hybrid vehicle that uses both of them as drive sources, or a vehicle equipped with other drive sources. In addition, the vehicle 1 can be equipped with various transmission devices, and can be equipped with various devices required to drive the internal combustion engine and the electric motor, such as systems, components, etc. In addition, the mode, number, layout, etc. of the devices related to the drive of the wheels 3 in the vehicle 1 can be set in various ways.

[0024] First, with reference to Figures 1 to 4 , the configuration of the vehicle 1 of the present embodiment will be described. Figure 1 It is an illustrative perspective view showing a state in which a part of the passenger compartment of the vehicle 1 of the embodiment is seen through. Figure 2 It is an illustrative top view (bird's-eye view) of the vehicle 1 of the embodiment. Figure 3This is a diagram showing an example of the instrument panel of the vehicle 1 according to the embodiment as viewed from the rear of the vehicle. Figure 4 This is an exemplary block diagram of the configuration of the parking assistance system 100 according to the embodiment.

[0025] As Figure 1 Illustrated, the vehicle body 2 forms a passenger compartment 2a in which passengers not shown ride. Inside the passenger compartment 2a, a steering control unit 4, an acceleration operation unit 5, a braking operation unit 6, a shift operation unit 7, etc. are provided in a state facing the seat 2b of the driver as a passenger. The steering control unit 4 is, for example, a steering wheel protruding from the instrument panel 24. The acceleration operation unit 5 is, for example, an accelerator pedal located under the driver's foot. The braking operation unit 6 is, for example, a brake pedal located under the driver's foot. The shift operation unit 7 is, for example, a shift lever protruding from the center console. In addition, the steering control unit 4, the acceleration operation unit 5, the braking operation unit 6, the shift operation unit 7, etc. are not limited thereto.

[0026] In addition, a display device 8 as a display output unit and a sound output device 9 as a sound output unit are provided in the passenger compartment 2a. The display device 8 is, for example, an LCD (Liquid Crystal Display), an OELD (Organic Electro-Luminescent Display), etc. The sound output device 9 is, for example, a speaker. In addition, the display device 8 is, for example, covered with a transparent operation input unit 10 such as a touch panel. The passenger can visually confirm the image on the display screen of the display device 8 via the operation input unit 10. In addition, the passenger can perform operation input by touching, pressing, or moving the operation input unit 10 at a position corresponding to the image on the display screen of the display device 8 using a finger or the like. These display device 8, sound output device 9, operation input unit 10, etc. are provided, for example, in a monitor device 11 located at the center in the vehicle width direction, i.e., the left-right direction, of the instrument panel 24. The monitor device 11 can have operation input units not shown such as a switch, a dial, a joystick, and a button. In addition, a sound output device not shown can be provided at another position in the passenger compartment 2a different from the monitor device 11, and sound can be output from the sound output device 9 of the monitor device 11 and the other sound output device. In addition, the monitor device 11 can, for example, also serve as a navigation system and an audio system.

[0027] In addition, a display device 12 different from the display device 8 is provided in the passenger compartment 2a. As Figure 3As illustrated, the display device 12 is provided, for example, in the instrument panel portion 25 of the instrument panel 24, and is located between the speed display portion 25a and the engine speed display portion 25b at approximately the center of the instrument panel portion 25. The size of the screen 12a of the display device 12 is smaller than the size of the screen 8a of the display device 8. The display device 12 can mainly display an image representing information related to the parking assistance of the vehicle 1. The amount of information displayed on the display device 12 may be less than the amount of information displayed on the display device 8. The display device 12 is, for example, an LCD, an OELD, or the like. In addition, the information displayed on the display device 12 may be displayed on the display device 8.

[0028] In addition, as Figure 1 , 2 illustrated, the vehicle 1 is, for example, a four-wheel vehicle and has two left and right front wheels 3F and two left and right rear wheels 3R. It can be configured such that all four of these wheels 3 can be steered. As Figure 4 illustrated, the vehicle 1 has a steering system 13 that steers at least two of the wheels 3. The steering system 13 has an actuator 13a and a torque sensor 13b. The steering system 13 is electrically controlled by an ECU 14 (Electronic Control Unit) or the like to operate the actuator 13a. The steering system 13 is, for example, an electric power steering system, an SBW (Steer By Wire) system, or the like. The steering system 13 supplements the steering force by applying a torque, i.e., an assist torque, to the steering portion 4 by the actuator 13a, or steers the wheels 3 by the actuator 13a. In this case, the actuator 13a can steer one wheel 3 or multiple wheels 3. In addition, the torque sensor 13b detects, for example, the torque applied by the driver to the steering portion 4.

[0029] In addition, as Figure 2 illustrated, four photographing portions 15a to 15d are provided, for example, on the vehicle body 2 as the multiple photographing portions 15. The photographing portion 15 is, for example, a digital camera incorporating a photographing element such as a CCD (Charge Coupled Device) or a CIS (CMOS Image Sensor). The photographing portion 15 can output video data at a prescribed frame rate. The photographing portions 15 each have a wide-angle lens or a fish-eye lens and can photograph a range of, for example, 140° to 190° in the horizontal direction. In addition, the optical axes of the photographing portions 15 are set to face obliquely downward. Thereby, the photographing portions 15 sequentially photograph the external environment around the vehicle body 2 including the road surface on which the vehicle 1 can move and the area where the vehicle 1 can park, and output the data as photographed image data.

[0030] The imaging unit 15a is located, for example, at the end portion 2e on the rear side of the vehicle body 2, and is provided on the wall portion below the door 2h of the trunk. The imaging unit 15b is located, for example, at the end portion 2f on the right side of the vehicle body 2, and is provided on the right side rearview mirror 2g. The imaging unit 15c is located, for example, at the front side of the vehicle body 2, i.e., the front side in the vehicle longitudinal direction, at the end portion 2c, and is provided on the front bumper or the like. The imaging unit 15d is located, for example, at the left side of the vehicle body 2, i.e., the left side in the vehicle width direction, at the end portion 2d, and is provided on the rearview mirror 2g which is a protruding portion on the left side. The ECU 14 can perform arithmetic processing and image processing based on the image data obtained by the plurality of imaging units 15, and generate an image with a wider viewing angle, or generate a virtual bird's-eye view image of the vehicle 1 observed from above.

[0031] In addition, the ECU 14 recognizes the dividing lines or the like shown on the road surface around the vehicle 1 based on the images of the imaging unit 15, and detects (extracts) the parking area shown by the dividing lines or the like.

[0032] In addition, as Figure 1 , 2 exemplified, four distance measuring units 16a to 16d and eight distance measuring units 17a to 17h are provided on the vehicle body 2, for example, as the plurality of distance measuring units 16 and 17. The distance measuring units 16 and 17 are, for example, sonars that emit ultrasonic waves and capture the reflected waves. The sonar can also be referred to as a sonar sensor or an ultrasonic detector. The ECU 14 can determine the presence or absence of an object such as an obstacle around the vehicle 1 and the distance to the object based on the detection results of the distance measuring units 16 and 17. That is, the distance measuring units 16 and 17 are an example of a detection unit for detecting an object. In addition, the distance measuring unit 17 can be used, for example, for detecting objects at relatively short distances, and the distance measuring unit 16 can be used, for example, for detecting objects at relatively long distances farther than the distance measuring unit 17. In addition, the distance measuring unit 17 can be used, for example, for detecting objects in front of and behind the vehicle 1, and the distance measuring unit 16 can be used for detecting objects on the side of the vehicle 1.

[0033] In addition, as Figure 4As illustrated, in the parking assistance system 100, in addition to the ECU 14, the monitor device 11, the steering system 13, the distance measuring units 16 and 17, etc., there are also the braking system 18, the steering angle sensor 19, the acceleration sensor 20, the shift sensor 21, the wheel speed sensor 22, etc. electrically connected via the in-vehicle network 23 which is an electrical communication line. The in-vehicle network 23 is configured as, for example, a CAN (Controller Area Network). The ECU 14 can control the steering system 13, the braking system 18, etc. by sending control signals via the in-vehicle network 23. In addition, the ECU 14 can receive the detection results of the torque sensor 13b, the braking sensor 18b, the steering angle sensor 19, the distance measuring units 16, the distance measuring unit 17, the acceleration sensor 20, the shift sensor 21, the wheel speed sensor 22, etc., the operation signals of the operation input unit 10, etc. via the in-vehicle network 23.

[0034] The ECU 14 has, for example, a CPU 14a (Central Processing Unit), a ROM 14b (ReadOnly Memory), a RAM 14c (Random Access Memory), a display control unit 14d, a sound control unit 14e, an SSD 14f (Solid State Drive (solid state disk), flash memory), etc. The CPU 14a can read out the programs installed and stored in non-volatile storage devices such as the ROM 14b and perform various arithmetic processes and controls according to the programs. The RAM 14c temporarily stores various data used in the arithmetic operations of the CPU 14a. In addition, the display control unit 14d mainly performs image processing using the image data obtained by the imaging unit 15 and synthesis of the image data to be displayed on the display device 8 in the arithmetic processes of the ECU 14. In addition, the sound control unit 14e mainly performs processing of the sound data output from the sound output device 9 in the arithmetic processes of the ECU 14. In addition, the SSD 14f is a rewritable non-volatile storage unit and can store data even when the power supply of the ECU 14 is turned off. In addition, the CPU 14a, the ROM 14b, the RAM 14c, etc. can be integrated in the same package. In addition, the ECU 14 can be configured to use other logical operation processors or logic circuits such as a DSP (Digital Signal Processor) instead of the CPU 14a. In addition, an HDD (Hard Disk Drive) can be provided instead of the SSD 14f, or the SSD 14f and the HDD can be provided separately from the ECU 14.

[0035] The braking system 18 is, for example, an ABS (Anti-lock Brake System) that suppresses the locking of the brakes, an anti-skid device (ESC: Electronic Stability Control) that suppresses the skidding of the vehicle 1 during turning, an electric braking system that enhances the braking force (performs brake assist), a BBW (Brake By Wire), or the like. The braking system 18 applies a braking force to the wheels 3 via the actuator 18a, and thus applies a braking force to the vehicle 1. In addition, the braking system 18 can detect signs of brake locking, wheel 3 spinning, skidding, etc. based on the rotational difference between the left and right wheels 3, etc., and perform various controls. The braking sensor 18b is, for example, a sensor that detects the position of the movable part of the braking operation unit 6. The braking sensor 18b can detect the position of the brake pedal as the movable part. The braking sensor 18b includes a displacement sensor.

[0036] The steering angle sensor 19 is, for example, a sensor that detects the amount of steering operation of the steering operation unit 4 such as the steering wheel. The steering angle sensor 19 is constituted by, for example, a Hall element or the like. The ECU 14 obtains the amount of steering operation of the driver on the steering operation unit 4, the amount of steering operation of each wheel 3 during automatic steering operation, etc. from the steering angle sensor 19, and performs various controls. In addition, the steering angle sensor 19 detects the rotational angle of the rotating part included in the steering operation unit 4. The steering angle sensor 19 is an example of an angle sensor.

[0037] The acceleration sensor 20 is, for example, a sensor that detects the position of the movable part of the acceleration operation unit 5. The acceleration sensor 20 can detect the position of the acceleration pedal as the movable part. The acceleration sensor 20 includes a displacement sensor.

[0038] The shift sensor 21 is, for example, a sensor that detects the position of the movable part of the shift operation unit 7. The shift sensor 21 can detect the position of a lever, an arm, a button, etc. as the movable part. The shift sensor 21 may include a displacement sensor or may be constituted as a switch.

[0039] The wheel speed sensor 22 is a sensor that detects the rotational amount of the wheel 3 and the number of revolutions per unit time. The wheel speed sensor 22 outputs the number of wheel speed pulses indicating the detected number of revolutions as a sensor value. The wheel speed sensor 22 can be constituted by, for example, a Hall element or the like. The ECU 14 performs arithmetic operations on the moving amount of the vehicle 1, etc. based on the sensor value obtained from the wheel speed sensor 22, and performs various controls. In addition, the wheel speed sensor 22 may also be provided in the braking system 18. In this case, the ECU 14 obtains the detection result of the wheel speed sensor 22 via the braking system 18.

[0040] In addition, the configurations, arrangements, electrical connection methods, etc. of the various sensors and actuators described above are an example, and various settings (changes) can be made.

[0041] Next, with reference to Figure 5 , the functional configuration of the ECU 14 of the parking assistance system 100 according to the embodiment will be described. Figure 5 is an exemplary block diagram of the functional configuration of the ECU 14 of the parking assistance system 100 according to the embodiment. As Figure 5 shown, the ECU 14 includes a first required driving force generation unit 141, a second required driving force generation unit 142, a mediation unit 143, and a driving force generation control unit 144 as functional configurations. In Figure 4 the ECU 14, each unit 141 to 144 is implemented by the CPU 14a executing, for example, a parking assistance program stored in the ROM 14b. In addition, it may be configured to use two or more ECUs to implement each unit 141 to 144. Alternatively, it may be configured to implement each unit 141 to 144 using hardware.

[0042] In addition, in the following examples, the first required driving force generation unit 141 and the second required driving force generation unit 142 are implemented by different application programs, respectively.

[0043] When the vehicle 1 is to stop, the first required driving force generation unit 141 calculates the target traveling speed of the vehicle 1 for parking assistance, and generates a first required driving force based on the target traveling speed and the actual speed of the vehicle 1.

[0044] The second required driving force generation unit 142 generates a second required driving force to reduce the damage caused by a collision of the vehicle. The second required driving force is, for example, the maximum required driving force for the purpose of stopping the vehicle 1. In other words, for example, when it is determined based on the detection results of the ranging units 16 and 17 that there are other vehicles, pedestrians, or other objects near the moving predetermined direction of the vehicle 1, the second required driving force generation unit 142 generates a second required driving force with a smaller value in order to suppress the traveling speed of the vehicle 1 to be slower.

[0045] The mediation unit 143 compares the first required driving force and the second required driving force, and selects the smaller one and outputs it to the driving force generation control unit 144.

[0046] Based on either the first required driving force or the second required driving force received from the mediation unit 143, the driving force generation control unit 144 controls the drive mechanism so that a driving force for the traveling of the vehicle 1 is generated.

[0047] Moreover, when the second required driving force is selected by the mediation unit 143, the first required driving force generation unit 141 performs at least any one of a first control that does not increase the first required driving force until the first required driving force is selected by the next mediation unit 143, and a second control that recalculates the first required driving force based on the actual speed at that time when the first required driving force is selected by the next mediation unit.

[0048] In addition, when the second required driving force is selected by the mediation unit 143 and when the vehicle wants to start from a stopped state, the first required driving force generation unit 141 performs the first control.

[0049] In addition, when the second required driving force is selected by the mediation unit 143 and when the vehicle is in the process of traveling, the first required driving force generation unit 141 performs the second control.

[0050] In addition, the first required driving force generation unit 141 also performs a level difference control that raises the first required driving force when the vehicle crosses a level difference. Moreover, when the second required driving force is selected by the mediation unit 143 and when the vehicle crosses a level difference, the first required driving force generation unit 141 stops the level difference control until the first required driving force is selected by the next mediation unit 143.

[0051] Next, with reference to Figure 6 , the start-up processing of the first required driving force generation unit 141 will be described. Figure 6 It is an exemplary flowchart of the start-up processing of the first required driving force generation unit 141 in the ECU 14 of the parking assistance system 100 of the embodiment. In addition, before starting this start-up processing, the vehicle 1 is in a stopped state.

[0052] First, in step S1, the first required driving force generation unit 141 determines whether to start the start-up operation of the vehicle 1. If so, it proceeds to step S2; if not, it returns to step S1. For example, when the driver of the vehicle 1 performs an operation for starting parking assistance through the operation input unit 10 or the like, it is "yes" in step S1.

[0053] In step S2, the first required driving force generation unit 141 determines whether the mediation result is the first required driving force. If so, it proceeds to step S3; if not, it proceeds to step S4.

[0054] For example, when there are other vehicles, pedestrians, or other objects near the vehicle 1 in the vicinity of the predetermined moving direction, the second required driving force generated by the second required driving force generation unit 142 becomes a smaller value in order to reduce the damage caused by a collision of the vehicle. In this way, the mediation unit 143 compares the first required driving force and the second required driving force, and selects the smaller second required driving force. In this case, the answer in step S2 is no.

[0055] In addition, for example, when there are no other vehicles, pedestrians, or other objects near the vehicle 1 in the vicinity of the predetermined moving direction, the second required driving force generated by the second required driving force generation unit 142 does not become a smaller value. In this way, the mediation unit 143 compares the first required driving force and the second required driving force, and selects the smaller first required driving force. In this case, the answer in step S2 is yes.

[0056] In step S3, the first required driving force generation unit 141 increases the first required driving force.

[0057] Next, in step S4, the first required driving force generation unit 141 determines whether the vehicle 1 has started to move. If yes, the process ends. If no, the process returns to step S2.

[0058] Next, with reference to Figure 7 , the changes over time of each parameter during vehicle start-up in the comparative example and the embodiment will be described. Figure 7 FIG. is a timing chart exemplarily showing the changes over time of each parameter during vehicle start-up in (a) the comparative example and (b) the embodiment. In addition, the following Figure 7 , Figure 8 , Figure 10 The purpose of the figures shown is to schematically show the overview.

[0059] As shown in (a) of Figure 7 , in the case of the comparative example (prior art), at the start of the vehicle, the first required driving force D1 starts to increase from time T1. At time T2, the mediation result is switched from the first required driving force S1 to the second required driving force S2. In this way, after time T2, since the actual speed of the vehicle does not reach the target driving speed, the first required driving force generation unit (corresponding to the first required driving force generation unit 141) continues to increase the first required driving force D1.

[0060] Then, if at time T3, the mediation result is switched from the second required driving force S2 to the first required driving force S1, the driving force generation control unit (corresponding to the driving force generation control unit 144) generates a driving force according to the increased first required driving force, so a sudden acceleration (peak acceleration H1) of the vehicle 1 is caused.

[0061] On the other hand, as shown in (b) of Figure 7 , in the case of the parking assistance system 100 of the present embodiment, until time T2, it is the same as (a) of Figure 7 . At time T2, the mediation result is switched from the first required driving force S1 to the second required driving force S2. In this way, as shown in the flowchart of Figure 6 , since step S2 is NO and step S3 is skipped, the first required driving force generation unit 141 does not increase the first required driving force D1.

[0062] Then, even at time T3, when the mediation result is switched from the second required driving force S2 to the first required driving force S1, since the first required driving force D1 does not increase from time T2, sudden acceleration of the vehicle 1 will not occur. After that, if the first required driving force generation unit 141 increases the first required driving force D1, at time T4, the vehicle 1 starts to move, and the vehicle 1 accelerates slowly (peak acceleration H2 < peak acceleration H1).

[0063] In this way, according to the parking assistance system 100 of the present embodiment, at the start of the vehicle 1 from a stopped state, even when the mediation unit 143 selects the second required driving force, by the first required driving force generation unit 141 performing the first control of not increasing the first required driving force until the mediation unit 143 selects the first required driving force next, it is possible to avoid unwanted sudden acceleration. In other words, at the start of the vehicle 1, it is possible to achieve good ride comfort with less impact for the passengers.

[0064] Next, with reference to Figure 8 , Figure 9 , the processing during the driving of the first required driving force generation unit 141 will be described. Figure 8 is a timing chart exemplarily showing the change over time of the correction amount and the like during the vehicle driving in the comparative example and the embodiment. In addition, hereinafter, the correction amount refers to the amount used to correct the time-series target value by adding the difference between the time-series target value and the actual value to the time-series target value when calculating the first required driving force. Here, the time-series target value refers to, for example, the target values of the position, speed, and acceleration of the vehicle 1 after one second, two seconds, three seconds,.... Hereinafter, mainly the case of the target value of the speed will be described as the time-series target value.

[0065] As Figure 8As shown in (a) of the figure, in the case of the comparative example (prior art), until time T41, the mediation result is (1) the first required driving force, and the sum of the target value (speed target value, target driving speed) and the correction amount (hereinafter, also referred to as "the sum".) is consistent with the actual value (the value of the actual speed). In other words, the correction amount is 0. After that, if at time T41 the mediation result switches from (1) the first required driving force to (2) the second required driving force, since the actual value does not reach the target value, the first required driving force generation unit 141 increases the correction amount in order to increase the first required driving force D1.

[0066] Then, if at time T42 the mediation result switches from (2) the second required driving force to (1) the first required driving force, the sum is larger than the actual value, so a larger first required driving force is calculated, causing a sudden acceleration of the vehicle 1.

[0067] On the other hand, as Figure 8 shown in (b) of the figure, in the case of this embodiment, until time T42 is the same as Figure 8 (a) of the figure, but if at time T42 the mediation result switches from (2) the second required driving force to (1) the first required driving force, the first required driving force generation unit 141 resets the correction amount to 0. As a result, the sum is consistent with the actual value, and an appropriate first required driving force is calculated, without causing a sudden acceleration of the vehicle 1. Refer to Figure 9 to describe the process for implementing this content.

[0068] Figure 9 is an exemplary flowchart of the processing during driving of the first required driving force generation unit 141 in the ECU 14 of the parking assistance system 100 of the embodiment.

[0069] First, in step S11, the first required driving force generation unit 141 generates a time-series target value (target values of position, speed, acceleration) based on the current state (current position, speed, acceleration) of the vehicle 1.

[0070] Next, in step S12, the first required driving force generation unit 141 calculates the correction amount based on the time-series target value and the actual value.

[0071] Next, in step S13, the first required driving force generation unit 141 generates the first required driving force based on the time-series target value and the correction amount.

[0072] Next, in step S14, the first required driving force generation unit 141 determines whether the mediation result is a switch from the second required driving force to the first required driving force. If so, it proceeds to step S15; if not, it returns to step S11.

[0073] In other words, the mediation result is initially the first required driving force. Thereafter, whether this state continues or the mediation result switches from the first required driving force to the second required driving force, the processes of step S11 → step S12 → step S13 → step S14 (No) → step S11 →... are repeated. Moreover, if the mediation result switches from the second required driving force to the first required driving force, then at step S14 (Yes), the process proceeds to step S15.

[0074] In step S15, the first required driving force generation unit 141 resets the correction amount to 0.

[0075] Next, in step S16, the first required driving force generation unit 141 generates the first required driving force based on the time-series target value.

[0076] Next, in step S17, the first required driving force generation unit 141 determines whether the vehicle 1 has reached the target position for parking. If so, the process ends; if not, the process proceeds to step S18.

[0077] In step S18, the first required driving force generation unit 141 generates the time-series target value according to the current state of the vehicle 1.

[0078] Next, in step S19, the first required driving force generation unit 141 calculates the correction amount based on the time-series target value and the actual value.

[0079] Next, in step S20, the first required driving force generation unit 141 generates the first required driving force based on the time-series target value and the correction amount. After step S20, the process returns to step S17.

[0080] Next, with reference to Figure 10 , the changes over time of each parameter during the vehicle driving process in the comparative example and the embodiment will be described. Figure 10 A time-sequence diagram exemplarily showing the changes over time of each parameter during the vehicle driving process in (a) the comparative example and (b) the embodiment.

[0081] As Figure 10 shown in (a) of [], in the case of the comparative example (prior art), during the vehicle driving process, until time T21, the mediation result is the first required driving force S1, and the vehicle 1 travels based on the first required driving force D1. Then, at time T21, the mediation result switches from the first required driving force S1 to the second required driving force S2. As a result, after time T21, since the actual speed of the vehicle 1 has not reached the target speed, the first required driving force generation unit (corresponding to the first required driving force generation unit 141) continues to increase the first required driving force D1.

[0082] Then, if at time T22, the mediation result is to switch from the second required driving force S2 to the first required driving force S1, the driving force generation control unit (corresponding to the driving force generation control unit 144) generates a driving force according to the increased first required driving force, thus causing a sudden acceleration (peak acceleration H3) of the vehicle 1.

[0083] On the other hand, as Figure 10 shown in (b), in the case of the parking assistance system 100 of the present embodiment, until time T22, it is the same as Figure 10 (a). If at time T22, the mediation result is to switch from the second required driving force S2 to the first required driving force S1, the first required driving force generation unit 141 resets the correction amount to 0 ( Figure 9 step S14 of : Yes → step S15). Therefore, the vehicle 1 accelerates slowly (peak acceleration H4 < peak acceleration H3).

[0084] In this way, according to the parking assistance system 100 of the present embodiment, during the driving of the vehicle 1, even when the mediation unit 143 selects the second required driving force, by the first required driving force generation unit 141 executing the second control of recalculating the first required driving force based on the actual speed at this time when the mediation unit 143 selects the first required driving force next, it is also possible to avoid an undesired sudden acceleration. In other words, during the driving of the vehicle 1, good ride comfort with less impact on passengers can be achieved.

[0085] In addition, when the mediation unit 143 selects the second required driving force and the vehicle 1 crosses a height difference, the first required driving force generation unit 141 stops the height difference control until the mediation unit 143 selects the first required driving force next. Thereby, an undesired sudden acceleration caused by the height difference control of the vehicle 1 can be avoided.

[0086] As described above, according to the parking assistance system 100 of the present embodiment, even when the second required driving force is selected, by executing at least any one of the above first control and second control, it is also possible to avoid an undesired sudden acceleration when the required driving force selected later changes from the second required driving force to the first required driving force.

[0087] In addition, in the ECU 14, for example, the state of the prior art is maintained without changing the second required driving force generation unit 142, the mediation unit 143, and the driving force generation control unit 144, and only the first required driving force generation unit 141 needs to be changed, so the corresponding costs and work are less.

[0088] In addition, it may also be configured such that a parking assistance program executed by the CPU 14a of the present embodiment is recorded in a computer-readable recording medium such as a CD-ROM, a floppy disk (FD), a CD-R, or a DVD (Digital Versatile Disk), in a format that can be installed or executed, and provided thereby.

[0089] Furthermore, it may also be configured such that the parking assistance program is stored in a computer connected to a network such as the Internet, and provided by downloading it via the network. Additionally, it may also be configured to provide or distribute the parking assistance program executed in the present embodiment via a network such as the Internet.

[0090] The above-described embodiments of the present invention do not limit the scope of the invention, but are merely examples included in the scope of the invention. A certain embodiment of the present invention may also be an embodiment obtained by, for example, changing, omitting, or adding at least a part of the specific use, structure, shape, operation, and effect of the above-described embodiment, without departing from the gist of the invention.

Claims

1. A parking assist device, comprising: a first required driving force generation unit that, when the vehicle is to park, calculates a target traveling speed of the vehicle and generates a first required driving force based on the target traveling speed and an actual speed of the vehicle; and a mediation unit that obtains the second required driving force from a second required driving force generation unit that generates a second required driving force to reduce damage caused by a collision of the vehicle, compares the first required driving force and the second required driving force, and selects the smaller one and outputs it to a driving force generation control unit, when the mediation unit selects the second required driving force, The above-described first required driving force generation unit executes at least any one of the first control and the second control, where, in the first control, until the mediation unit next selects the first required driving force, the first required driving force is not increased from the first required driving force when the mediation unit selects the second required driving force, and in the second control, when the mediation unit next selects the first required driving force, the first required driving force is recalculated based on the actual speed of the vehicle when the mediation unit selects the first required driving force.

2. The parking assist device according to claim 1, wherein when the mediation unit selects the second required driving force and when the vehicle wants to start from a stopped state, the first required driving force generation unit performs the first control.

3. The parking assist device according to claim 1, wherein when the mediation unit selects the second required driving force and when the vehicle is in a traveling state, the first required driving force generation unit performs the second control.

4. The parking assist device according to claim 1, wherein the first required driving force generation unit also performs a height difference control that raises the first required driving force when the vehicle crosses a height difference, when the mediation unit selects the second required driving force and when the vehicle crosses a height difference, the first required driving force generation unit stops the height difference control until the mediation unit next selects the first required driving force.

5. A parking assist method, comprising: a first required driving force generation step in which, when the vehicle is to park, a target traveling speed of the vehicle is calculated and a first required driving force is generated based on the target traveling speed and an actual speed of the vehicle; and a mediation step in which the second required driving force is obtained from a second required driving force generation unit that generates a second required driving force to reduce damage caused by a collision of the vehicle, the first required driving force and the second required driving force are compared, and the smaller one is selected and output to a driving force generation control unit, when the second required driving force is selected in the mediation step, In the above-described first required driving force generation step, at least any one of the first control and the second control is executed. In the first control, until the first required driving force is selected in the subsequent mediation step, the first required driving force is not increased from the first required driving force when the second required driving force is selected in the mediation step. In the second control, when the first required driving force is selected in the subsequent mediation step, the first required driving force is recalculated based on the actual speed of the vehicle when the first required driving force is selected in the mediation step.

6. A recording medium storing a parking assistance program for causing a computer to execute the following steps: A first required driving force generation step in which, when the vehicle is to stop, the target traveling speed of the vehicle is calculated, and a first required driving force is generated based on the target traveling speed and the actual speed of the vehicle; and A mediation step in which the second required driving force is obtained from a second required driving force generation unit that generates a second required driving force to reduce damage caused by a collision of the vehicle, the first required driving force and the second required driving force are compared, and the smaller one is selected and output to a driving force generation control unit. When the second required driving force is selected in the above-described mediation step, In the above first required driving force generation step, at least any one of the first control and the second control is performed, where, In the first control, until the first required driving force is selected in the subsequent mediation step, the first required driving force is not increased from the first required driving force when the second required driving force is selected in the mediation step. In the second control, when the first required driving force is selected in the subsequent mediation step, the first required driving force is recalculated based on the actual speed of the vehicle when the first required driving force is selected in the mediation step.

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