Travel control device, travel control method, and program product

Abstract

A travel control device, a travel control method, and a program product for suppressing deviation of a vehicle from a target trajectory due to a slope of a road surface when the inclination direction of the slope of the road surface changes sharply. A travel control device (100) controls a vehicle (10) to travel along a target trajectory (L0). A travel control device (100) is provided with: a slope acquisition unit (131) that acquires a slope angle of a slope road on which a vehicle (10) travels; a deviation calculation unit (132) that calculates a lateral deviation between the position of the target trajectory (L0) and the position of the vehicle (10) in the lateral direction; and a steering control unit (133) that calculates a target steering angle of the vehicle (10) on the basis of the ramp angle and the lateral deviation, and controls steering of the vehicle (10) so as to follow the target steering angle, in which a limit (104) variably set in accordance with the ramp angle is provided for an FB integral term (102) of the target steering angle calculated on the basis of the ramp angle and the lateral deviation.

Description

Technical Field

[0001] The present invention relates to a travel control device, a travel control method, and a program for controlling a vehicle to travel along a target track. Background Art

[0002] In recent years, efforts have been actively made to realize a sustainable transportation system that also takes into account people who are particularly vulnerable among traffic participants. To achieve this goal, research and development related to driving assistance technology are being carried out to further improve traffic safety and convenience. As a driving assistance technology, lane keeping assistance is known, which assists the driver's steering operation to keep the vehicle traveling near the center of the lane.

[0003] For example, Patent Document 1 describes a vehicle steering assistance device that performs steering assistance control to make the host vehicle travel along a target travel line. In particular, Patent Document 1 describes the following: During a slope transition period immediately after it is determined that the traveling road surface has switched from a non-slope road surface to a slope road surface, the control gain of an integral control term set by integrating the lateral deviation of the host vehicle is set to a value higher than the normal value.

[0004] In addition, Patent Document 2 describes a vehicle control device that controls the steering of the host vehicle to make the host vehicle travel on a target travel trajectory for lane change. In particular, Patent Document 2 describes the following: The vehicle control device corrects the target steering angle based on the slope of the host lane and the slope of the adjacent lane, and performs steering control to follow the corrected target steering angle. The slope of the host lane represents the slope of the road surface in the width direction of the host lane, and the slope of the adjacent lane represents the slope of the road surface in the width direction of the adjacent lane that is the destination of the lane change from the host lane.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent No. 7028115 Gazette

[0008] Patent Document 2: International Publication No. 2022 / 259552 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In the case where the slope angle of the road surface changes rapidly, for example, when the inclination direction of the road surface changes rapidly from right to left or from left to right, a state may occur in which the steering remains in the direction of vehicle drift caused by the slope, and there is a risk that the vehicle deviates from the target track.

[0011] In Patent Document 1, the timing for setting the control gain of the integral control term to a value higher than the normal value is immediately after it is determined that the vehicle has switched from a non-sloped road surface to a sloped road surface. Therefore, in the case where the inclination direction of the slope changes abruptly, there remains a possibility that the vehicle will deviate. In addition, in Patent Document 2, the target steering angle is corrected based on the slope information of the road surface obtained in advance from the map database. Therefore, it does not correspond to an abrupt change in the inclination direction of the slope. Regarding such an abrupt change in the slope angle, there is still room for research in suppressing the deviation of the vehicle from the target track.

[0012] The present invention provides a driving control device, a driving control method, and a program that can suppress the deviation of a vehicle from a target track due to a slope of a road surface in the case where the slope angle of the road surface changes abruptly. Furthermore, it contributes to the development of a sustainable transportation system.

[0013] Means for solving the problem

[0014] The present invention provides a driving control device that controls a vehicle to travel along a target track, and includes:

[0015] a slope acquisition unit that acquires a slope angle indicating the degree of inclination of the road surface on which the vehicle travels in the lateral direction;

[0016] a deviation calculation unit that calculates a lateral deviation between the position of the target track and the position of the vehicle in the lateral direction; and

[0017] a control unit that calculates a target steering angle of the vehicle based on the slope angle and the lateral deviation, and controls the steering of the vehicle to follow the target steering angle,

[0018] For a feedback term of the target steering angle calculated based on the slope angle and the lateral deviation, a limit that is variably set according to the slope angle is provided.

[0019] In addition, the present invention provides a driving control method for controlling a vehicle to travel along a target track, including:

[0020] a slope acquisition step of acquiring a slope angle indicating the degree of inclination of the road surface on which the vehicle travels in the lateral direction;

[0021] a deviation calculation step of calculating a lateral deviation between the position of the target track and the position of the vehicle in the lateral direction; and

[0022] a steering control step of calculating a target steering angle of the vehicle based on the slope angle and the lateral deviation, and controlling the steering of the vehicle to follow the target steering angle,

[0023] For a feedback term of the target steering angle calculated based on the ramp angle and the lateral deviation, a limit variably set according to the ramp angle is provided.

[0024] Furthermore, the present invention provides a program for controlling a vehicle to travel along a target track, which causes a computer to execute:

[0025] A ramp acquisition step of acquiring a ramp angle representing a lateral inclination of a road surface on which the vehicle travels;

[0026] A deviation calculation step of calculating a lateral deviation between a position of the target track and a position of the vehicle in the lateral direction; and

[0027] A steering control step of calculating a target steering angle of the vehicle based on the ramp angle and the lateral deviation, and controlling steering of the vehicle to follow the target steering angle,

[0028] For a feedback term of the target steering angle calculated based on the ramp angle and the lateral deviation, a limit variably set according to the ramp angle is provided.

[0029] Advantageous Effects of the Invention

[0030] According to the present invention, in a case where a tilt direction of a ramp on a road surface changes abruptly, an increase in a lateral deviation of the vehicle with respect to a target track can be reduced, and deviation of the vehicle from the target track can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a block diagram showing an internal structure of a vehicle equipped with a travel control device according to an embodiment of the present invention.

[0032] Figure 2 is a diagram showing an example of a situation where a vehicle executing lane keeping control travels on a ramp road sloping downward on the right side.

[0033] Figure 3 is a block diagram showing control executed by a travel control device when a vehicle travels on a ramp road.

[0034] Figure 4 is a diagram showing an example of a situation where a vehicle travels on a road surface where a ramp sloping downward on the right side abruptly changes to a ramp sloping downward on the left side.

[0035] Figure 5 (a) to (d) of is a diagram for explaining a method of setting a limit.

[0036] Figure 6 is an example of a flowchart of control executed by a travel control device.

[0037] Description of Reference Numerals:

[0038] 10: Vehicle

[0039] 12a: Camera (sensor)

[0040] 12c: Lateral acceleration sensor (sensor)

[0041] 12d: Yaw rate sensor (sensor)

[0042] 100: Driving control device

[0043] 101: FF term (feedforward term)

[0044] 102: FB integral term (feedback term)

[0045] 104: Limit

[0046] 131: Ramp acquisition unit

[0047] 132: Deviation calculation unit

[0048] 133: Steering control unit (control unit). Detailed implementation manner

[0049] Hereinafter, a driving control device, a driving control method, and a program according to an embodiment of the present invention will be described based on the accompanying drawings.

[0050] Figure 1 It is a block diagram showing the internal structure of the vehicle 10. The vehicle 10 includes a sensor group 12, a navigation device 14, a communication device 15, an electric power steering system 40 (also referred to as an EPS (Electric Power Steering) system 40), a driving force control system 50, a braking force control system 60, and a driving control device 100.

[0051] The sensor group 12 acquires various detection values for control of the driving control device 100 and the like. The sensor group 12 has, for example, a camera 12a that captures the surroundings of the vehicle 10, a vehicle speed sensor 12b that detects the speed of the vehicle 10, a lateral acceleration sensor 12c that detects the acceleration of the vehicle 10 in the lateral direction (hereinafter, also referred to as lateral acceleration), and a yaw rate sensor 12d that detects the angular velocity of the vehicle 10 about the vertical axis, that is, the yaw rate. In addition, the sensor group 12 may further have other sensors, for example, a wheel sensor that detects the rotational speed of the wheels, a gyro sensor that detects the respective speeds in a specified direction, and the like.

[0052] The navigation device 14 detects the current position of the vehicle 10 using, for example, GPS (Global Positioning System), and guides the user to the destination. The navigation device 14 has a storage device (not shown) having a map information database. In the map information database, as road information, information related to the curvature of a curve, the slope angle of the road surface described later, etc. may be included.

[0053] The communication device 15 is a communication interface for communicating with an external device. Communication between the vehicle 10 and the external device can be achieved, for example, using a mobile communication network such as a cellular network, Wi-Fi (registered trademark), Bluetooth (registered trademark), etc.

[0054] The EPS system 40 includes a steering angle sensor 41, a torque sensor 42, an EPS motor 43, a resolver 44, and an EPS ECU (Electronic Control Unit) 45. The steering angle sensor 41 detects the steering angle θst of the steering device 46. The torque sensor 42 detects the torque TQ applied to the steering device 46. The EPS motor 43 can assist the operation of the steering device 46 by applying a driving force or a reaction force to the steering column 47 connected to the steering device 46. The resolver 44 detects the rotation angle θm of the EPS motor 43. The EPS ECU 45 is responsible for the overall control of the EPS system 40. Specifically, the EPS ECU 45 controls the steering of the steering device 46 based on an instruction from the steering control unit 133 of the travel control device 100 described later.

[0055] The driving force control system 50 has a drive ECU 51 that performs driving force control of the vehicle 10. The drive ECU 51 controls a motor, an internal combustion engine, etc., which are the drive sources of the vehicle 10, based on the user's acceleration operation of the accelerator pedal 52, thereby controlling the driving force of the vehicle 10.

[0056] The braking force control system 60 has a brake ECU 61 that performs braking force control of the vehicle 10. The brake ECU 61 controls a braking mechanism, etc., based on the user's braking operation of the brake pedal 62, thereby controlling the braking force of the vehicle 10.

[0057] The driving control device 100 performs driving-related controls such as steering, driving, and braking of the vehicle 10, and has a driving assistance function for assisting the driver. As one of the driving assistance functions, the driving control device 100 is configured to be able to execute lane keeping control, which enables the vehicle 10 to travel on a target track set within the lane without relying on the driver's driving operation or assisted driving operation. The target track of the vehicle 10 is, for example, the center line of the lane that is the center position of the lane in which the vehicle 10 travels, and more specifically, the center position of the white lines provided on both the left and right sides of the lane.

[0058] The driving control device 100 includes an input / output unit 110, a storage unit 120, and an arithmetic unit 130. The arithmetic unit 130 is constituted by, for example, a CPU (Central Processing Unit). The arithmetic unit 130 controls each unit based on the programs stored in the storage unit 120, thereby performing various controls. In addition, the arithmetic unit 130 performs input / output of signals with each unit connected to the driving control device 100 via the input / output unit 110.

[0059] The arithmetic unit 130 includes, for example: a slope acquisition unit 131 that acquires the slope angle of a road surface (hereinafter, also referred to as a slope road) provided with a slope that is the lateral inclination of the road; a deviation calculation unit 132 that calculates the lateral deviation between the position of the target track of the vehicle 10 in the lateral direction and the current position of the vehicle 10; and a steering control unit 133 that controls the steering of the vehicle 10.

[0060] The slope acquisition unit 131 acquires the slope angle based on, for example, the detection results of a sensor group 12 such as the lateral acceleration of the vehicle 10 detected by a lateral acceleration sensor 12c and the yaw rate of the vehicle 10 detected by a yaw rate sensor 12d. The slope angle represents the degree of lateral inclination of the slope road. In addition, the slope angle can be detected by various methods. For example, the slope acquisition unit 131 can also acquire the slope angle through a sensor (including a camera 12a) that detects the inclination of the road surface. Specifically, the slope acquisition unit 131 can acquire the slope angle based on the detection results of the camera 12a, and in the case where the sensor group 12 has an inclination sensor that detects the inclination angle of the vehicle 10 in the vehicle width direction, the slope acquisition unit 131 can also acquire the slope angle based on the detection results of the inclination sensor. In addition, the slope acquisition unit 131 can also acquire information on the slope angle of a road pre-registered in a map information database or the like.

[0061] The deviation calculation unit 132 calculates the lateral deviation between the position of the target track of the vehicle 10 in the lateral direction and the current position of the vehicle 10 based on the detection information such as that of the camera 12a.

[0062] The steering control unit 133 sends a steering control instruction to the EPS system 40 to cause the vehicle 10 to travel along the target track.

[0063] Figure 2 This is an example of a case where the vehicle 10 that is performing lane keeping control is traveling on a downward sloping ramp on the right side. In addition, Figure 2 (and the following Figure 4 ) depicts the ramp as a straight line in the traveling direction of the vehicle 10, but it may also be curved (i.e., a bend).

[0064] When the vehicle 10 is traveling on a ramp, a yaw rate to the right is generated with respect to the target track L0 (dotted line). The vehicle 10 drifts to the right of the target track L0 and deviates from the target track L0. Therefore, the driving control device 100 performs control through lane keeping control to suppress the rightward drift of the vehicle 10 and return the vehicle 10 to the target track L0. At this time, the target steering angle of the vehicle 10 is set to the left, which is the direction opposite to the direction in which the vehicle 10 drifts due to the ramp, with respect to the reference steering angle that follows the target track L0 in the absence of a ramp. Although not shown, when the vehicle 10 is traveling on a downward sloping ramp on the left side, a yaw rate to the left is generated with respect to the target track L0. The vehicle 10 drifts to the left of the target track L0 and deviates from the target track L0. Therefore, the driving control device 100 performs control through lane keeping control to suppress the leftward drift of the vehicle 10 and return the vehicle 10 to the target track L0. At this time, the target steering angle of the vehicle 10 is set to the right, which is the direction opposite to the direction in which the vehicle 10 drifts due to the ramp, with respect to the reference steering angle that follows the target track L0 in the absence of a ramp.

[0065] Figure 3 This is a block diagram showing the control performed by the driving control device 100 when the vehicle 10 is traveling on a ramp. The driving control device 100 calculates the target steering angle through feedforward control and feedback control. In addition, in the following description and figures, "feedforward" is also referred to as "FF", and "feedback" is also referred to as "FB".

[0066] The driving control device 100 calculates the target steering angle based on the FF term 101 obtained from the ramp angle, the FB integral term 102 for ramp compensation, and the FB integral term 103 based on the lateral deviation. The FF term 101 is a term that ensures high responsiveness, and the FB integral terms 102 and 103 are terms that compensate for modeling errors or interference effects with respect to the FF term 101.

[0067] ​

[0068] The FB integral term 102 of the target steering angle is a term that suppresses the lateral drift of the vehicle 10 caused by the slope through feedback control, and is set based on the slope angle and the lateral deviation. Specifically, the FB integral term 102 is a term that corrects the target steering angle when the vehicle 10 is traveling on a slope road so that the lateral deviation caused by the slope does not increase.

[0069] The FB integral term 103 of the target steering angle is a term that makes the lateral deviation approach zero and makes the vehicle 10 approach the target track L0 through feedback control, and is set based on the lateral deviation. Specifically, the FB integral term 103 is a term that corrects the target steering angle in the direction of decreasing the lateral deviation when the vehicle 10 is traveling on a slope road.

[0070] The travel control device 100 calculates the target steering angle by adding the FB integral term 102 and the FB integral term 103 to the FF term 101, and controls the steering of the vehicle 10 to follow the target steering angle.

[0071] As Figure 4 shown, when the slope road descends steeply from the right to the left in the traveling direction of the vehicle 10, after the sharp change in the inclination direction, a state may temporarily occur in which the target steering angle to the left corresponding to the right-down slope (specifically, the target steering angle to the left with respect to the above-mentioned reference steering angle) remains. This is caused, for example, by the operation delay of the EPS system 40 for the steering device 46, the control delay of the travel control device 100 for the FB control, the acquisition delay of the slope angle, etc. At this time, both the direction of the drift of the vehicle 10 caused by the left-down slope and the direction of the target steering angle of the vehicle 10 are to the left, so the lateral deviation of the vehicle 10 becomes larger to the left, and the vehicle 10 may deviate significantly from the target track L0.

[0072] Therefore, as Figure 3 shown, the FB integral term 102 for slope compensation is provided with a limit 104 that is variably set according to the slope angle. Since the limit 104 is provided for the FB integral term 102, the calculated target steering angle does not increase to an unnecessary extent with respect to the lateral drift of the vehicle 10 caused by the slope. Therefore, even when the inclination direction of the slope road changes sharply, it is possible to reduce the increase in the lateral deviation of the vehicle 10 with respect to the target track L0, and it is possible to suppress the deviation of the vehicle 10 from the target track L0.

[0073] More specifically, the travel control device 100 calculates the target steering angle by adding the FB integral term 102 with the limit 104 calculated based on the slope angle and the lateral deviation to the FF term 101 calculated based on the slope angle. Therefore, it is possible to appropriately set the target steering angle through FF control and FB control based on the slope angle and the lateral deviation.

[0074] Figure 5 Figures (a) to (d) are graphs for explaining the setting method of the limit 104. The horizontal axis of the four graphs is the slope angle, and the vertical axis is the yaw rate. In this specification, the slope angle of a slope road with a downward slope on the left is defined as positive, and the slope angle of a slope road with a downward slope on the right is defined as negative. In addition, corresponding to the downward slope on the left, the yaw rate and the steering angle to the right with respect to the reference steering angle for following the target track L0 in the absence of a slope are defined as positive, and corresponding to the downward slope on the right, the yaw rate and the steering angle to the left with respect to the reference steering angle are defined as negative for explanation purposes.

[0075] First, the travel control device 100 calculates the optimal yaw rate with respect to the lateral drift of the vehicle 10 caused by the slope. Specifically, the travel control device 100 calculates the upper limit value of the yaw rate (hereinafter, also referred to as the yaw rate upper limit value) that can suppress the lateral drift of the vehicle 10 caused by the slope without increasing the target steering angle to an unnecessary level, and sets the optimal yaw rate that does not exceed the upper limit value. The yaw rate upper limit value is calculated based on, for example, the following formula (1), and the graph is represented by the curve depicted by the thick solid line in Figure 5 Figure (a).

[0076] γ = Av / (1 + Av 2 ) × gsinθ (1)

[0077] Here, γ is the yaw rate upper limit value, A is a stability coefficient representing the handling performance of the vehicle 10, v is the speed of the vehicle 10, g is the acceleration due to gravity, and θ is the slope angle of the slope road. The yaw rate upper limit value is a function of the slope angle and is variable according to the slope angle. In this specification, when the slope angle is positive, the yaw rate upper limit value takes a positive (i.e., to the right) value, and when the slope angle is negative, the yaw rate upper limit value takes a negative (i.e., to the left) value.

[0078] In addition, the yaw rate upper limit value is not limited to the above formula (1). For example, it can also be calculated by further considering the specification information of the vehicle 10, specifically, information such as the vehicle weight and wheelbase, with respect to the above formula (1).

[0079] After calculating the yaw rate upper limit value, the travel control device 100 determines the first prohibited area R1 ( Figure 5 the shaded area in Figure (a)) where the yaw rate of the vehicle 10 exceeds the yaw rate upper limit value. When setting the target steering angle such that the yaw rate is included in the first prohibited area R1, the target steering angle will increase to an unnecessary level. Therefore, the travel control device 100 calculates the optimal target steering angle so that the yaw rate is not included in the first prohibited area R1. Specifically, when the slope angle is zero or more, the upper side area of the yaw rate upper limit value becomes the first prohibited area R1. In addition, when the slope angle is less than zero, the lower side area of the yaw rate upper limit value becomes the first prohibited area R1.

[0080] Next, as shown in (b) of Figure 5 , the travel control device 100 determines a second prohibited area R2 that satisfies the condition that the direction of the yaw rate does not match the direction of the drift of the vehicle 10 caused by the slope. When the yaw rate is included in the second prohibited area R2, the target steering angle is set in the direction in which the lateral deviation increases. Therefore, the travel control device 100 calculates the target steering angle so that the yaw rate is not included in the second prohibited area R2. Specifically, when the slope angle is zero or more, the area where the yaw rate is negative, that is, the area of the yaw rate to the left with respect to the reference steering angle, becomes the second prohibited area R2. In addition, when the slope angle is less than zero, the area where the yaw rate is positive, that is, the area of the yaw rate to the right with respect to the reference steering angle, becomes the second prohibited area R2.

[0081] Next, as shown in (c) of Figure 5 , the travel control device 100 combines the first prohibited area R1 and the second prohibited area R2 determined in (a) and (b) of Figure 5 . The travel control device 100 sets the lower edge portions of the first prohibited area R1 and the second prohibited area R2 on the upper side of the curve graph (hereinafter also referred to as the upper side boundary 104a) and the upper edge portions of the first prohibited area R1 and the second prohibited area R2 on the lower side (hereinafter also referred to as the lower side boundary 104b) as the boundaries. In addition, the "boundary" here is Figure 5 the value before adjustment shown in (d) of

[0082] Finally, as shown in (d) of Figure 5 , the travel control device 100 adjusts the boundary so that the boundary also functions in the case where the slope angle is near zero. Thereby, generation of control noise can be suppressed. Specifically, the upper side boundary 104a and the lower side boundary 104b are blunted near the slope angle of zero, and a predetermined width is provided between the upper side boundary 104a and the lower side boundary 104b, thereby completing the setting of the boundary 104 shown in Figure 3 .

[0083] The travel control device 100 sets the target steering angle so that the yaw rate does not exceed the boundary 104. Specifically, it is not greater than the upper side boundary 104a of the boundary 104 and not less than the lower side boundary 104b of the boundary 104.

[0084] The setting of the above-described limit 104 is performed, for example, when the lateral movement of the vehicle 10 based on a slope road is detected. In other words, it is performed before the inclination direction of the slope road changes abruptly. Thus, the limit 104 can be appropriately set in advance before the inclination direction of the slope road changes abruptly. However, the timing of setting the limit 104 is not limited to this. It can also be set when a slope road ahead is detected by the camera 12a or the like before traveling on the slope road (i.e., when traveling on a flat road), or when referring to the map information database when traveling on a flat road, identifying and obtaining the information of the slope angle before the slope road, and setting the limit 104.

[0085] Figure 6 An example of a flowchart showing the control executed by the travel control device 100. The travel control device 100 repeatedly executes at a predetermined cycle Figure 6 of the flowchart.

[0086] The travel control device 100 determines whether the lateral movement of the vehicle 10 caused by a slope is detected (step S1). If the lateral movement is not detected (step S1: No), the travel control device 100 ends this flowchart.

[0087] If the lateral movement is detected (step S1: Yes), the travel control device 100 obtains the slope angle of the road surface (step S2) and calculates the lateral deviation of the vehicle 10 (step S3). In addition, the order of steps S2 and S3 can be reversed or they can be executed simultaneously.

[0088] Next, the travel control device 100 sets the limit 104 by the above method (step S4), and calculates the target steering angle in consideration of the limit 104 (step S5). Then, the travel control device 100 controls the steering of the vehicle 10 to follow the target steering angle (step S6).

[0089] In addition, the control method described in the foregoing embodiment can be implemented by a computer executing a pre-prepared program. This program is stored in a storage medium readable by a computer and is executed by being read out from the storage medium. In addition, this program can be provided in a form stored in a non-temporary storage medium such as a flash memory, or can be provided via a network such as the Internet. The computer that executes this program can be included in the control device, or can be included in an electronic device such as a smartphone, a tablet terminal, or a personal computer that can communicate with the control device, or can also be included in a server device that can communicate with these control devices and electronic devices.

[0090] As described above, an embodiment of the present invention has been described with reference to the accompanying drawings. However, the present invention is of course not limited to this embodiment. Those skilled in the art should understand that various modification examples or correction examples can obviously be conceived within the scope described in the technical solution, and these modification examples or correction examples also of course belong to the technical scope of the present invention. In addition, within the scope not departing from the gist of the invention, the constituent elements in the above-described embodiment can be arbitrarily combined.

[0091] For example, when the deviation between the current steering angle and the target steering angle is large when the vehicle 10 is traveling on a slope road, it is also possible to set a limit on the change amount of the steering angle per unit time when approaching the target steering angle. Thereby, an increase in the sudden yaw rate of the vehicle 10 can be suppressed.

[0092] In addition, in order to be able to reduce the excessive steering control of the travel control device 100 when the vehicle 10 is traveling on a road surface without a slope, it is also possible to set a dead zone in which the steering control based on the slope angle is not executed when the slope angle is near zero.

[0093] In addition, in the above-described embodiment, the travel control device 100 calculates the target steering angle by adding the FB integral term 102 for slope compensation and the FB integral term 103 based on the lateral deviation to the FF term 101. However, it is also possible to further add the FB differential term based on the lateral deviation, the FB term based on the attitude angle, etc. to calculate the target steering angle.

[0094] In addition, in the above-described embodiment, the travel control device 100 calculates the limit 104 based on the specified information related to the vehicle 10 (for example, vehicle speed, stability coefficient, specification information, etc.). However, for example, it is also possible to further consider the slip angle and the friction coefficient of the road surface to calculate the limit 104.

[0095] At least the following matters are described in this specification. In the parentheses, the corresponding constituent elements, etc. in the above-described embodiment are shown as an example, but are not limited thereto.

[0096] (1) A travel control device (travel control device 100) that controls a vehicle (vehicle 10) to travel along a target track (target track L0), wherein

[0097] the travel control device includes:

[0098] a slope acquisition unit (slope acquisition unit 131) that acquires a slope angle indicating the degree of inclination in the lateral direction of the road surface on which the vehicle travels;

[0099] a deviation calculation unit (deviation calculation unit 132) that calculates a lateral deviation between the position of the target track in the lateral direction and the position of the vehicle; and

[0100] A control unit (steering control unit 133) that calculates a target steering angle of the vehicle based on the ramp angle and the lateral deviation, and controls the steering of the vehicle to follow the target steering angle.

[0101] For a feedback term (FB integral term 102) of the target steering angle calculated based on the ramp angle and the lateral deviation, a limit (limit 104) that is variably set according to the ramp angle is provided.

[0102] In the case where the inclination direction of the slope of the road surface changes abruptly (specifically, when changing abruptly from right to left or from left to right), a state may occur where the steering remains in the direction of vehicle drift caused by the slope, and there is a risk that the vehicle deviates from the target track. According to (1), a limit that is variably set according to the ramp angle is provided in the feedback term of the target steering angle. Therefore, even when the inclination direction of the slope of the road surface changes abruptly, an increase in the lateral deviation of the vehicle relative to the target track can be reduced, and deviation of the vehicle from the target track can be suppressed. In addition, even when the road surface changes abruptly from a sloped road to a non-sloped road, an increase in the lateral deviation of the vehicle relative to the target track can be reduced, and deviation of the vehicle from the target track can be suppressed.

[0103] (2) The driving control device according to (1), wherein

[0104] The limit is set based on an upper limit value of the yaw rate and a condition that the direction of the yaw rate of the vehicle does not coincide with the downward inclination direction of the road surface.

[0105] The upper limit value of the yaw rate is variably set according to the ramp angle and is calculated based on specified information related to the vehicle.

[0106] According to (2), by setting a limit based on the yaw rate of the vehicle, it is possible to suppress the target steering angle from being set in the direction of increasing the lateral deviation of the vehicle.

[0107] (3) The driving control device according to (2), wherein

[0108] The upper limit value of the yaw rate is calculated based on the speed of the vehicle.

[0109] According to (3), it is possible to set an appropriate limit considering the speed of the vehicle.

[0110] (4) The driving control device according to (2) or (3), wherein

[0111] The upper limit value of the yaw rate is calculated based on the specification information of the vehicle.

[0112] According to (4), it is possible to set an appropriate limit considering the specification information of the vehicle.

[0113] The traveling control device according to any one of (1) to (4), wherein,

[0114] When detecting the movement of the vehicle in the lateral direction generated based on the slope of the road surface, the control unit sets the limit.

[0115] According to (5), it is possible to appropriately set the limit in advance before the inclination direction of the slope of the road surface changes sharply.

[0116] The traveling control device according to any one of (1) to (5), wherein,

[0117] The slope acquisition unit acquires the slope angle based on at least one of the detection results of sensors (lateral acceleration sensor 12c, yaw rate sensor 12d) for detecting the lateral acceleration of the vehicle, the detection results of sensors (tilt sensor, camera 12a) for detecting the inclination of the road surface, and map information.

[0118] According to (6), it is possible to appropriately acquire the slope angle based on sensors, map information, etc.

[0119] The traveling control device according to any one of (1) to (6), wherein,

[0120] The control unit calculates the target steering angle by adding the feedback term with the limit set based on the slope angle and the lateral deviation and the feedforward term (FF term 101) calculated based on the slope angle.

[0121] According to (7), it is possible to appropriately set the target steering angle through feedforward control and feedback control based on the slope angle and the lateral deviation.

[0122] (8) A traveling control method for controlling a vehicle (vehicle 10) to travel along a target track (target track L0), wherein,

[0123] The traveling control method includes:

[0124] A slope acquisition step of acquiring a slope angle indicating the inclination degree of the road surface on which the vehicle travels in the lateral direction;

[0125] A deviation calculation step of calculating a lateral deviation between the position of the target track and the position of the vehicle in the lateral direction; and

[0126] A steering control step of calculating a target steering angle of the vehicle based on the slope angle and the lateral deviation and controlling the steering of the vehicle to follow the target steering angle,

[0127] For a feedback term (FB integral term 102) of the target steering angle calculated based on the ramp angle and the lateral deviation, a limit (limit 104) that is variably set according to the ramp angle is provided.

[0128] In a case where the inclination direction of the ramp of the road surface changes abruptly (specifically, when changing abruptly from right to left or from left to right), a state may occur in which the steering remains in the direction of vehicle drift caused by the ramp, and there is a risk that the vehicle deviates from the target track. According to (8), a limit that is variably set according to the ramp angle is provided for the feedback term of the target steering angle. Therefore, even in a case where the inclination direction of the ramp of the road surface changes abruptly, an increase in the lateral deviation of the vehicle with respect to the target track can be reduced, and deviation of the vehicle from the target track can be suppressed.

[0129] (9) A program that controls a vehicle (vehicle 10) to travel along a target track (target track L0) and causes a computer (travel control device 100) to execute:

[0130] A ramp acquisition step of acquiring a ramp angle indicating the lateral inclination degree of the road surface on which the vehicle travels;

[0131] A deviation calculation step of calculating a lateral deviation between the position of the target track and the position of the vehicle in the lateral direction; and

[0132] A steering control step of calculating a target steering angle of the vehicle based on the ramp angle and the lateral deviation and controlling the steering of the vehicle to follow the target steering angle,

[0133] For a feedback term (FB integral term 102) of the target steering angle calculated based on the ramp angle and the lateral deviation, a limit (limit 104) that is variably set according to the ramp angle is provided.

[0134] In a case where the inclination direction of the ramp of the road surface changes abruptly (specifically, when changing abruptly from right to left or from left to right), a state may occur in which the steering remains in the direction of vehicle drift caused by the ramp, and there is a risk that the vehicle deviates from the target track. According to (9), a limit that is variably set according to the ramp angle is provided for the feedback term of the target steering angle. Therefore, even in a case where the inclination direction of the ramp of the road surface changes abruptly, an increase in the lateral deviation of the vehicle with respect to the target track can be reduced, and deviation of the vehicle from the target track can be suppressed.

Claims

1. A travel control device that controls a vehicle to travel along a target track, wherein, the travel control device includes: a slope acquisition unit that acquires a slope angle indicating the degree of inclination of the road surface on which the vehicle travels in the lateral direction; a deviation calculation unit that calculates a lateral deviation between the position of the target track and the position of the vehicle in the lateral direction; and a control unit that calculates a target steering angle of the vehicle based on the slope angle and the lateral deviation, and controls the steering of the vehicle to follow the target steering angle, for a feedback term of the target steering angle calculated based on the slope angle and the lateral deviation, a limit variably set according to the slope angle is provided.

2. The travel control device according to claim 1, wherein, the limit is set based on a yaw rate upper limit value and a condition that the direction of the yaw rate of the vehicle does not coincide with the downward inclination direction of the road surface, the yaw rate upper limit value is variably set according to the slope angle and is calculated based on specified information related to the vehicle.

3. The travel control device according to claim 2, wherein, the yaw rate upper limit value is calculated based on the speed of the vehicle.

4. The travel control device according to claim 2, wherein, the yaw rate upper limit value is calculated based on the specification information of the vehicle.

5. The travel control device according to claim 1, wherein, when it is detected that the vehicle moves in the lateral direction due to the slope of the road surface, the control unit sets the limit.

6. The travel control device according to claim 1, wherein, the slope acquisition unit acquires the slope angle based on at least one of a detection result of a sensor that detects the lateral acceleration of the vehicle, a detection result of a sensor that detects the inclination of the road surface, and map information.

7. The travel control device according to any one of claims 1 to 6, wherein, the control unit calculates the target steering angle by adding the feedback term with the limit set based on the slope angle and the lateral deviation and a feedforward term calculated based on the slope angle.

8. A travel control method that controls a vehicle to travel along a target track, wherein, the travel control method includes: a slope acquisition step of acquiring a slope angle indicating the degree of inclination of the road surface on which the vehicle travels in the lateral direction; a deviation calculation step of calculating a lateral deviation between the position of the target track and the position of the vehicle in the lateral direction; and a steering control step of calculating a target steering angle of the vehicle based on the slope angle and the lateral deviation, and controlling the steering of the vehicle to follow the target steering angle, for a feedback term of the target steering angle calculated based on the slope angle and the lateral deviation, a limit variably set according to the slope angle is provided.

9. A program product that includes a program for controlling a vehicle to travel along a target track, wherein, the program causes a computer to execute: a slope acquisition step of acquiring a slope angle indicating the degree of inclination of the road surface on which the vehicle travels in the lateral direction; A deviation calculation step that calculates a lateral deviation between the position of the target track in the lateral direction and the position of the vehicle; and A steering control step that calculates a target steering angle of the vehicle based on the slope angle and the lateral deviation, and controls the steering of the vehicle to follow the target steering angle, For a feedback term of the target steering angle calculated based on the slope angle and the lateral deviation, a limit variably set according to the slope angle is provided.

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