Vehicle Motion Control Device and Vehicle Motion Control Method

Abstract

The present invention provides a vehicle motion control device that generates a driving path with small behavior of a vehicle during cornering and realizes a comfortable riding quality even when driving on a continuous curve where the distance between curves is restricted. The vehicle motion control device of the present invention is characterized in that it has a driving trajectory generation unit, and the driving trajectory generation unit sets the curvature of the driving path when driving on the curve with a smaller curvature among the first curve and the second curve to be larger than the curvature of the curve, and sets the curvature of the driving path when driving on the curve with a larger curvature to be smaller than the curvature of the curve, based on the information of the curvature of the first curve and the second curve connected to the first curve on the lane in the traveling direction of the vehicle, to generate a driving path.

Description

Technical Field

[0001] The present invention relates to a vehicle motion control device and a vehicle motion control method for generating a driving trajectory serving as a driving target of a vehicle and controlling the motion of the vehicle based on the generated driving trajectory. Background Art

[0002] As a vehicle motion control technology, the following technology is known: a driving trajectory consisting of information such as a driving path and driving speed is generated as a driving target of the vehicle, and the power transmission, braking device, steering device, etc. are controlled so that the vehicle follows the generated driving trajectory.

[0003] Furthermore, as the simplest driving route, some vehicles use the center of the lane as the driving route.

[0004] As background art in such a technical field, there is Japanese Patent Application Laid-Open No. 2017-100652 (Patent Document 1).

[0005] Patent document 1 describes a driving trajectory generating device that determines whether there is a curved path specified by a curvature radius within a predetermined path range from the current position of the vehicle along the travel direction in a predetermined lane driving path representing the center of the lane. When it is determined that a curved path exists and a predetermined driving trajectory for the vehicle to travel is generated, the curved path, which is a trajectory corresponding to the predetermined driving trajectory, is set as a turning line, and the predetermined driving trajectory is generated in such a way that the curvature radius of the turning line is greater than the curvature radius of the curved path (see abstract).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-100652 Summary of the Invention

[0009] Problem that the invention aims to solve

[0010] The driving trajectory generating device described in Patent Document 1 generates a planned driving trajectory such that the curvature radius of the curve line (driving path when traveling on a curve) is larger than the curvature radius of the curved path (road shape), thereby improving the ride quality of the vehicle.

[0011] However, the driving trajectory generation device described in Patent Document 1 always generates a planned driving trajectory in such a way that the curvature radius of the driving path when driving on a curve is larger than the curvature radius of the road shape. Therefore, the starting point and end point of the planned driving trajectory of a curve are outside the lane driving path.

[0012] Particularly at the connection points of continuous curves where there are restrictions on the distance between curves, it is necessary to connect two points on the outer side of the lane driving path, and the degree of freedom of the generated driving planned trajectory may be reduced.

[0013] That is to say, in the driving trajectory generation device described in Patent Document 1, it is sometimes only possible to generate a driving trajectory in the case of taking the center of the lane as the driving path and in the case of a driving path with an almost constant radius of curvature, and it may not be possible to obtain sufficient vehicle ride quality as required.

[0014] Therefore, the present invention provides a vehicle motion control device and a vehicle motion control method that can generate a driving path with small vehicle behavior during curve driving (during turning) and achieve a comfortable ride quality even when driving on continuous curves with restrictions on the distance between curves.

[0015] Technical means for solving the problem

[0016] To solve the above problems, the vehicle motion control device of the present invention is characterized in that it has a driving trajectory generation unit, and the driving trajectory generation unit sets the curvature of the driving path when driving on the curve with a smaller curvature among the first curve and the second curve to be larger than the curvature of the curve according to the curvature information of the first curve and the second curve connected to the first curve on the lane in the traveling direction of the vehicle, and sets the curvature of the driving path when driving on the curve with a larger curvature to be smaller than the curvature of the curve to generate a driving path.

[0017] In addition, to solve the above problems, the vehicle motion control method of the present invention sets the curvature of the driving path when driving on the curve with a smaller curvature among the first curve and the second curve to be larger than the curvature of the curve and sets the curvature of the driving path when driving on the curve with a larger curvature to be smaller than the curvature of the curve by means of the driving trajectory generation unit that generates the driving path according to the curvature information of the first curve and the second curve connected to the first curve on the lane in the traveling direction of the vehicle.

[0018] Effects of the invention

[0019] According to the present invention, it is possible to provide a vehicle motion control device and a vehicle motion control method that can generate a driving path with small vehicle behavior during curve driving (during turning) and achieve a comfortable ride quality even when driving on continuous curves with restrictions on the distance between curves.

[0020] Furthermore, problems, configurations, and effects other than the above will be clarified by the description of the following embodiments. Brief description of the drawings

[0021] Figure 1Explanation diagram for the configuration of the vehicle-mounted system 1 having the vehicle motion control device 2 described in Embodiment 1.

[0022] Figure 2 Explanation diagram for the functional blocks of the travel trajectory generation unit 22 described in Embodiment 1.

[0023] Figure 3 Flowchart for explaining the general processing of the path planning unit 22d described in Embodiment 1.

[0024] Figure 4 Explanation diagram for the travel path of the first example described in Embodiment 1.

[0025] Figure 5(a) is an explanation diagram for the curvature when traveling on the travel path of the first example described in Embodiment 1.

[0026] Figure 5(b) is an explanation diagram for the yaw rate when traveling on the travel path of the first example described in Embodiment 1.

[0027] Figure 5(c) is an explanation diagram for the lateral acceleration when traveling on the travel path of the first example described in Embodiment 1.

[0028] Figure 5(d) is an explanation diagram for the lateral jerk when traveling on the travel path of the first example described in Embodiment 1.

[0029] Figure 6 Explanation diagram for the travel path of the second example described in Embodiment 1.

[0030] Figure 7(a) is an explanation diagram for the curvature when traveling on the travel path of the second example described in Embodiment 1.

[0031] Figure 7(b) is an explanation diagram for the yaw rate when traveling on the travel path of the second example described in Embodiment 1.

[0032] Figure 7(c) is an explanation diagram for the lateral acceleration when traveling on the travel path of the second example described in Embodiment 1.

[0033] Figure 7(d) is an explanation diagram for the lateral jerk when traveling on the travel path of the second example described in Embodiment 1.

[0034] Figure 8 Explanation diagram for the functional blocks of the travel trajectory generation unit 22 described in Embodiment 2. Detailed implementation manner

[0035] Next, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, substantially the same or similar components are labeled with the same reference numerals, and in cases where the description is repetitive, the description may be omitted.

[0036] In addition, descriptions of well-known technologies may sometimes be omitted.

[0037] Embodiment 1

[0038] <Configuration of In-vehicle System 1>

[0039] First, the configuration of the in-vehicle system 1 having the vehicle motion control device 2 described in Embodiment 1 will be described.

[0040] Figure 1 It is an explanatory diagram for explaining the configuration of the in-vehicle system 1 having the vehicle motion control device 2 described in Embodiment 1.

[0041] The in-vehicle system 1 includes an out-vehicle communication device 11, a GNSS (Global Navigation Satellite System) 12, a map information storage unit 13, a sensor 14, an HMI (human machine interface) unit 15, a vehicle motion control device 2, a power transmission system 3, a braking system 4, and a steering system 5.

[0042] The in-vehicle system 1 is mounted in a vehicle and performs vehicle motion control such as autonomous driving or driving assistance of the vehicle.

[0043] The out-vehicle communication device 11 performs vehicle-to-vehicle communication with other vehicles or vehicle-to-roadside unit communication via wireless communication, and transmits and receives information such as the vehicle and the surrounding environment.

[0044] The GNSS 12 receives radio waves transmitted from artificial satellites such as quasi-zenith satellites or GPS (Global Positioning System) satellites, and acquires information such as the position of the vehicle (own vehicle).

[0045] The map information storage unit 13 stores general road information used in a navigation system, road information having information related to curves such as the width and curvature of the road, information such as road surface conditions and traffic conditions, and information on the driving state of other vehicles, that is, information such as the vehicle and the surrounding environment. Furthermore, the information such as the vehicle and the surrounding environment is sequentially updated by information obtained through vehicle-to-vehicle communication or vehicle-to-roadside unit communication via the out-vehicle communication device 11.

[0046] The sensor 14 is an external recognition sensor such as an image sensor, a millimeter-wave radar, or a lidar for detecting information about the vehicle and its surrounding environment, or a sensor for detecting information such as the driver's operations, the vehicle's speed, acceleration, jerk, angular velocity, and the steering angle of the wheels.

[0047] Information about the vehicle and its surrounding environment detected by the external recognition sensor is, for example, information about various objects such as obstacles, signs, lane boundary lines, outer lane lines, buildings, pedestrians, and other vehicles existing around the host vehicle. In addition, the sensor 14, for example, recognizes lane boundary lines and outer lane lines based on the difference in brightness between the white lines in the image data captured by the image sensor and the road surface.

[0048] The HMI unit 15 displays on the display and provides voice guidance from the speaker the information required by the user from the information received through user input operations such as the selection of the driving mode or the setting of the destination, the information acquired by the vehicle exterior communication device 11, the GNSS 12, and the sensor 14, and the information recorded in the map information storage unit 13. In addition, the HMI unit 15 generates an alarm to alert the user.

[0049] Here, the driving mode includes, for example, a comfort mode, an economy mode, a sport mode, etc. The driving mode can be arbitrarily set by the user, or preset by the user, or set by the operation management unit 21 described later according to the driving condition information, setting the vehicle's speed, acceleration, jerk, etc. That is, the driving mode changes the upper limit values of the vehicle's behavior.

[0050] In addition, the driving mode includes a shortest time mode for minimizing the travel time and a shortest distance mode for minimizing the travel distance.

[0051] The vehicle motion control device 2 includes an operation management unit 21, a travel trajectory generation unit 22, and a travel control unit 23. The operation management unit 21, the travel trajectory generation unit 22, and the travel control unit 23 are computers that comprehensively control the vehicle with hardware such as an arithmetic device (CPU: Central Processing Unit), a main storage device or an auxiliary storage device such as a semiconductor memory, and a communication device, and implement various functions by the arithmetic device executing the program loaded into the main storage device.

[0052] Furthermore, in Embodiment 1, for ease of explanation, the operation management unit 21, the travel trajectory generation unit 22, and the travel control unit 23 have separate configurations, but they do not necessarily have separate configurations. When these units are used in an actual vehicle, various functions of these units can also be implemented by a host controller.

[0053] The operation management unit 21 generates information on the position of its own vehicle, information on various objects existing around its own vehicle (information such as vehicles and the surrounding environment), lateral acceleration, yaw rate, lateral jerk, etc., which are related to the behavior of the vehicle, based on the information obtained by the vehicle exterior communication device 11, GNSS 12, sensor 14, and the information recorded in the map information storage unit 13.

[0054] Furthermore, the information related to the behavior of the vehicle is generated based on the information related to the curves on the path and the information on the speed when driving on the curves on the path.

[0055] In addition, the operation management unit 21 regularly transmits the information on the position of its own vehicle, the information on various objects, and the information related to the behavior of the vehicle to other vehicles and roadside units via the vehicle exterior communication device 11, and also transmits it to the map information storage unit 13 to sequentially update the information stored in the map information storage unit 13.

[0056] In addition, the operation management unit 21 sets the information on the path from the current position of the vehicle to the destination based on the information on the position of its own vehicle, the information on various objects, the information related to the behavior of the vehicle, and the information received by the HMI unit 15 (such as the driving mode and destination).

[0057] Furthermore, the information generated or set by the motion management unit 21 is sometimes hereinafter referred to as "driving condition information".

[0058] The driving trajectory generation unit 22 inputs the driving condition information and generates a driving trajectory composed of information such as a driving path (the path that becomes the driving target when the vehicle is driving on the road) and a driving speed (the speed that becomes the driving target when the vehicle is driving on the road), which becomes the driving target of the vehicle.

[0059] The driving control unit 23 sets the target driving force, target braking force, target steering angle, etc. in such a way that the vehicle follows the driving trajectory output from the driving trajectory generation unit 22, and controls the power transmission system 3, braking system 4, and steering system 5.

[0060] The power transmission system 3 controls the driving force generated by an internal combustion engine or an electric motor, etc. according to the driver's operation or the target driving force output from the driving control unit 23.

[0061] The braking system 4 controls the braking force generated by a brake caliper, etc. according to the driver's operation or the target braking force output from the driving control unit 23.

[0062] The steering system 5 controls the steering angle of the wheels according to the driver's operation or the target steering angle output from the driving control unit 23.

[0063] <Function blocks of the travel trajectory generation unit 22>

[0064] Next, the function blocks of the travel trajectory generation unit 22 described in Embodiment 1 will be described.

[0065] Figure 2 It is an explanatory diagram for explaining the function blocks of the travel trajectory generation unit 22 described in Embodiment 1.

[0066] The travel trajectory generation unit 22 inputs travel condition information and generates a travel trajectory composed of information such as a travel path and a travel speed, which is the travel target of the vehicle. It has an information acquisition unit 22a, a road determination unit 22b, a drivable area calculation unit 22c, a path planning unit 22d, a nearest neighbor point calculation unit 22e, a path determination unit 22f, and a speed planning unit 22g.

[0067] The information acquisition unit 22a acquires travel condition information from the operation management unit 21 and outputs it.

[0068] The road determination unit 22b inputs travel condition information, determines a road shape (bend shape) with a fixed curvature or having a peak or inflection point among multiple (two or more) bends on the lane in the traveling direction of the vehicle as one bend, detects the number (information) of bends in the traveling direction of the vehicle, and defines (acquires) and outputs information related to each detected bend such as the length, width, curvature, turning direction, starting point, and ending point of each detected bend.

[0069] Furthermore, hereinafter, a bend with a fixed curvature or a curvature forming a peak or inflection point may sometimes be referred to as a "peak curvature".

[0070] The drivable area calculation unit 22c inputs travel condition information, calculates and outputs a drivable area that can travel without contacting obstacles, pedestrians, buildings, other vehicles, etc. in the traveling direction of the vehicle. Furthermore, the drivable area calculation unit 22c may also calculate a risk potential map considering the moving range of other vehicles or the reach range in the movement of pedestrians (e.g., rushing onto the road) and output it as the drivable area.

[0071] The path planning unit 22d inputs travel condition information, information related to bends, and determination results (information) to generate a travel path.

[0072] The nearest neighbor point calculation unit 22e inputs the drivable area output from the drivable area calculation unit 22c and the travel path output from the path planning unit 22d, explores the nearest neighbor points of each point on the travel path and each point in the drivable area and the points facing the nearest neighbor points, and calculates and outputs the distance between each point and its nearest neighbor point and the distance between each point and the point facing the nearest neighbor point.

[0073] Here, the operation method in the nearest neighbor point operation unit 22e will be described.

[0074] First, since the drivable area is information with a specified width, multiple pairs of reference points can be plotted on both sides of the drivable area at a specified interval. For example, there are multiple reference points on the left side of the drivable area at a specified interval, and there are multiple reference points on the right side of the drivable area at a specified interval. That is, a pair is formed by the reference point on the left side and the reference point on the right side.

[0075] Next, search for the reference point (the first nearest neighbor point) that is the nearest neighbor corresponding to a certain point on the driving path, and search for the reference point (the second nearest neighbor point) that is paired with the nearest neighbor reference point (opposite to the first nearest neighbor point).

[0076] Here, for the convenience of description and for easier understanding, sometimes the reference point that is the nearest neighbor corresponding to a certain point on the driving path is called "nearest neighbor point A", and the reference point paired with the nearest neighbor reference point is called "nearest neighbor point B".

[0077] The nearest neighbor point operation unit 22e calculates and outputs, for each of the points on the driving path, the distance from a certain point on the driving path to the nearest neighbor point A, the distance from the certain point to the nearest neighbor point B, and the distance between the nearest neighbor point A and the nearest neighbor point B.

[0078] Furthermore, although it has been described that the drivable area is information with a specified width, it may not have a width due to the positions of obstacles, pedestrians, buildings, other vehicles, etc. or the speed of the vehicle. In this case, the nearest neighbor point operation unit 22e calculates the distance by treating the nearest neighbor point A and the nearest neighbor point B as the same point.

[0079] The path determination unit 22f inputs the distances from each point on the driving path to each nearest neighbor point A, the distances from each point to each nearest neighbor point B, and the distances between each nearest neighbor point A and each nearest neighbor point B output from the nearest neighbor point operation unit 22e, determines whether the driving path is within the drivable area, and outputs its determination result (information).

[0080] Here, the determination method in the path determination unit 22f will be described.

[0081] For a certain point on the driving path to be within the drivable area, the sum of the distance from the certain point on the driving path to the nearest neighbor point A and the distance from the certain point to the nearest neighbor point B needs to be equal to the distance between the nearest neighbor point A and the nearest neighbor point B.

[0082] That is, when the above-described relationship holds for all points on the driving path, it is determined that the driving path is within the drivable area, and when the above-described relationship does not hold, it is determined that the driving path is not within the drivable area.

[0083] The speed planning unit 22g inputs the driving condition information and the driving path output from the path planning unit 22d, sets the speed (driving speed) at each point on the driving path, and outputs it as a driving trajectory to the driving control unit 23.

[0084] Since the set driving mode changes the upper limit value of the vehicle's behavior, the speed planning unit 22g sets the driving speed at each point on the driving path so as to be below the upper limit value of the vehicle's behavior.

[0085] That is, in the speed planning unit 22g, the behavior of the vehicle occurring during driving on the driving path is calculated, and the driving speed is set and a driving trajectory is generated so as to be below the upper limit value of the vehicle's behavior set by the driving mode.

[0086] <Summary of the processing of the path planning unit 22d>

[0087] Next, the summary of the processing of the path planning unit 22d described in the first embodiment will be described.

[0088] Figure 3 It is a flowchart for explaining the summary of the processing of the path planning unit 22d described in the first embodiment.

[0089] Furthermore, in the first embodiment, for the sake of convenience in explanation and for easier understanding, the number of curves that are the objects of generating the driving path is set to two for explanation.

[0090] First, in step S101, the driving condition information output from the information acquisition unit 22a, the number of curves (information) existing in the traveling direction of the vehicle output from the road determination unit 22b, the length, width, curvature (peak curvature), turning direction, starting point, end point, etc. of each detected curve, and the determination result (information) as to whether the driving path is within the drivable area output from the path determination unit 22f are acquired. Thereafter, the process proceeds to step S102.

[0091] Next, in step S102, it is determined whether the driving path is outside the drivable area based on the determination result (information) obtained in step S101.

[0092] When the driving path is not outside the drivable area (No), the process ends.

[0093] When the driving path is outside the drivable area (Yes), the process proceeds to step S103.

[0094] Furthermore, step S102 is a step in the case where a driving path within the drivable area has been set. In the case where a driving path within the drivable area has not been set, step S102 is skipped.

[0095] Next, in step S103, based on the number (information) of curves existing in the traveling direction of the vehicle obtained in step S101, it is determined whether the number of curves is more than one.

[0096] In the case where the number of curves is one (No), proceed to step S104.

[0097] In the case where the number of curves is more than one (Yes), proceed to step S105.

[0098] In step S104, the peak curvature of the driving path when driving on the curve is set to a curvature smaller than the peak curvature of the road shape. Thereafter, proceed to step S112.

[0099] In step S105, based on the information of the peak curvature of each curve existing in the traveling direction of the vehicle obtained in step S101, it is determined whether there is a difference in the peak curvature between two curves.

[0100] Furthermore, hereinafter, sometimes one of the two curves closer to the vehicle is referred to as the "first curve", and one of the curves continuously connected to the first curve and farther from the vehicle is referred to as the "second curve". That is, for example, in an S-shaped curve, the first curve has an interval where the curvature increases and then decreases, and the second curve is adjacent to the first curve and has an interval where the curvature increases and then decreases.

[0101] In the case where there is no difference in the peak curvature between the first curve and the second curve (No), proceed to step S104.

[0102] In the case where there is a difference in the peak curvature between the first curve and the second curve (Yes), proceed to step S106.

[0103] In step S104, the peak curvature of the driving path when driving on the first curve and the peak curvature of the driving path when driving on the second curve (the peak curvature of the driving path when driving on the first curve = the peak curvature of the driving path when driving on the second curve) are set to a curvature smaller than the peak curvature of the road shape. Thereafter, proceed to step S112.

[0104] In step S106, based on the information of the turning directions of the first curve and the second curve existing in the traveling direction of the vehicle obtained in step S101, it is determined whether the turning direction of the first curve is different from the turning direction of the second curve.

[0105] When the turning direction of the first curve is not different (the same) from that of the second curve (no), proceed to step S107.

[0106] When the turning direction of the first curve is different (not the same) from that of the second curve (yes), proceed to step S109.

[0107] In step S107, based on the information of the peak curvatures of the first curve and the second curve existing in the traveling direction of the vehicle obtained in step S101, determine whether it is impossible to achieve the single-curve conversion of setting the two curves, i.e., the first curve and the second curve, as one curve.

[0108] Furthermore, the single-curve conversion is determined based on whether the difference between the peak curvature of the first curve and the peak curvature of the second curve is within a specified value. That is, when the difference is within the specified value, it is regarded as one curve, and when the difference is greater than the specified value, it is not regarded as one curve.

[0109] When single-curve conversion can be achieved (no), proceed to step S108.

[0110] When single-curve conversion can be achieved (yes), proceed to step S109.

[0111] In step S108, convert the two curves, i.e., the first curve and the second curve, into a single curve, and make the peak curvature of the first curve equal to the peak curvature of the second curve (peak curvature of the first curve = peak curvature of the second curve).

[0112] Subsequently, set the peak curvature of the traveling path when driving on the first curve and the peak curvature of the traveling path when driving on the second curve (peak curvature of the traveling path when driving on the first curve = peak curvature of the traveling path when driving on the second curve) to a curvature smaller than the peak curvature of the road shape. Then, proceed to step S112.

[0113] When equalizing the values, it can be set to the peak curvature of the first curve, or the peak curvature of the second curve, or the average value of the peak curvature of the first curve and the peak curvature of the second curve.

[0114] In step S109, based on the information of the peak curvatures of the curves existing in the traveling direction of the vehicle obtained in step S101, determine whether the peak curvature of the first curve is greater than the peak curvature of the second curve.

[0115] When the peak curvature of the first curve is less than the peak curvature of the second curve (no), proceed to step S111.

[0116] When the peak curvature of the first curve is greater than the peak curvature of the second curve (yes), proceed to step S110.

[0117] In step S111, set the peak curvature of the driving path when driving on the first curve to a curvature greater than the peak curvature of the road shape, and set the peak curvature of the driving path when driving on the second curve to a curvature smaller than the peak curvature of the road shape. Then, proceed to step S112.

[0118] In step S110, set the peak curvature of the driving path when driving on the first curve to a curvature smaller than the peak curvature of the road shape, and set the peak curvature of the driving path when driving on the second curve to a curvature greater than the peak curvature of the road shape. Then, proceed to step S112.

[0119] Next, in step S112, set the lengths of the straight line, transition curve, and circular curve sections on the driving path according to the information related to the curve obtained in step S101. Then, proceed to step S113.

[0120] Next, in step S113, set the starting point coordinates of the first curve according to the information related to the curve obtained in step S101. Then, proceed to step S114.

[0121] Next, in step S114, generate a driving path based on the peak curvature of the driving path when driving on the curve set in steps S104, S108, S111, and S110, the lengths of the respective sections set in step S112, and the starting point coordinates of the first curve set in step S113.

[0122] Furthermore, when step S102 is skipped, determine whether the generated driving path is within the drivable area. If the generated driving path is within the drivable area, end the process; if the generated driving path is not within the drivable area, return to step S101.

[0123] That is, the path planning unit 22d inputs the driving condition information output from the information acquisition unit 22a, the number of curves (information) existing in the traveling direction of the vehicle output from the road determination unit 22b, the length, width, curvature (peak curvature), turning direction, starting point, end point, etc. of each detected curve, and the determination result (information) of whether the driving path is within the drivable area output from the path determination unit 22f, and generates a driving path within the drivable area.

[0124] Thus, the vehicle motion control device 2 described in Embodiment 1 has a travel trajectory generation unit 22. The travel trajectory generation unit 22 sets the curvature of the travel path when traveling on the curve with a smaller curvature among the first curve and the second curve to be larger than the curvature of the curve, and sets the curvature of the travel path when traveling on the curve with a larger curvature to be smaller than the curvature of the curve, based on the information on the curvatures of the first curve and the second curve connected to the first curve on the lane in the traveling direction of the vehicle, thereby generating a travel path.

[0125] In addition, the vehicle motion control method described in Embodiment 1 sets the curvature of the travel path when traveling on the curve with a smaller curvature among the first curve and the second curve to be larger than the curvature of the curve, and sets the curvature of the travel path when traveling on the curve with a larger curvature to be smaller than the curvature of the curve, based on the information on the curvatures of the first curve and the second curve connected to the first curve on the lane in the traveling direction of the vehicle, by means of the travel trajectory generation unit 22 that generates the travel path.

[0126] Thus, according to Embodiment 1, even when traveling on a continuous curve where there is a restriction on the distance between curves (for example, a continuous curve where the straight line or the transition curve between curves is short, or a continuous curve where the curvatures of curves are different), it is possible to generate the following travel path: there is a large degree of freedom when generating the travel path, the behavior of the vehicle during curve travel is small, and a comfortable riding quality is achieved.

[0127] Furthermore, the so-called small behavior of the vehicle means that the magnitudes (absolute values) of the lateral acceleration, yaw rate, and lateral jerk from the zero position are small. In Embodiment 1, especially on a curve with a large curvature, it means that the absolute values of the lateral acceleration, yaw rate, and lateral jerk are smaller than those on a curve with a small curvature. In addition, it means that the lateral jerk (absolute value) near the inflection point of the curvature between curves is small.

[0128] In Embodiment 1, for the sake of convenience in explanation and for easier understanding, the number of curves that are the objects of generating the travel path is set to 2 for explanation.

[0129] Next, a brief explanation will be given for the case where the number of curves that are the objects of generating the travel path is 3 or more.

[0130] Furthermore, when the number of curves is 3 or more, the road determination unit 22b can also process along Figure 3 the flowchart shown, obtain information related to 3 or more curves (the number (information) of curves in the traveling direction of the vehicle, the length, width, curvature (peak curvature), turning direction, starting point, ending point, etc. of each detected curve), and generate a travel path.

[0131] When the number of curves is three or more, the path planning unit 22d sets the peak curvature of the driving path when driving on the curve with the maximum peak curvature to be smaller than the peak curvature of the road shape, sets the peak curvature of the driving path when driving on the curve with the minimum peak curvature to be larger than the peak curvature of the road shape, and sets the peak curvature of the driving path when driving on the curve with a peak curvature that is neither the maximum nor the minimum to be smaller than the maximum peak curvature of the road shape and larger than the minimum peak curvature of the road shape to generate the driving path.

[0132] In addition, a simple explanation will be given for the case where a third curve that is continuously connected to the second curve is newly detected while the vehicle is driving on the first curve.

[0133] In this case, it is also possible to proceed Figure 3 in accordance with the flowchart shown. The path planning unit 22d sets the peak curvature of the driving path when driving on the curve with the smaller peak curvature among the second curve and the third curve to be larger than the peak curvature of the road shape (the shape of the curve), and sets the peak curvature of the driving path when driving on the curve with the larger peak curvature to be smaller than the peak curvature of the road shape (the shape of the curve).

[0134] Here, when the turning directions of the second curve and the third curve are different, the point where the curvature between the first curve and the second curve on the driving path becomes 0 is used as the starting point to generate the driving paths of the second curve and the third curve.

[0135] In addition, when the turning directions of the second curve and the third curve are the same and the first curve and the second curve are not made into a single curve, the inflection point of the curvature between the first curve and the second curve on the driving path is used as the starting point to generate the driving paths of the second curve and the third curve.

[0136] In addition, when the turning directions of the second curve and the third curve are the same and the first curve and the second curve have been made into a single curve, the end point of the single curve on the driving path is used as the starting point, and the peak curvature of the driving path when driving on the third curve is set to be larger than the peak curvature of the road shape to generate the driving path.

[0137] Here, for example, an explanation will be given for the setting of the peak curvature of the driving path when driving at the peak curvature of the first curve (small: 1 / 50), the peak curvature of the second curve (medium: 1 / 40), and the peak curvature of the third curve (large: 1 / 30).

[0138] The peak curvature of the driving path when driving on the first curve becomes 1 / 47, and the peak curvature of the driving path when driving on the second curve becomes 1 / 42.

[0139] However, when a third curve that is continuously connected to the second curve is newly detected while the vehicle is traveling on the first curve, the peak curvature of the travel path when traveling on the second curve is changed.

[0140] The peak curvature of the travel path when traveling on the second curve becomes 1 / 38, and the peak curvature of the travel path when traveling on the third curve becomes 1 / 32.

[0141] Thus, according to Embodiment 1, even when traveling on three or more consecutive curves, the following travel path can be generated: there is a large degree of freedom in generating the travel path, the behavior of the vehicle during curve travel is small, and a comfortable riding quality is achieved.

[0142] 〈Travel Path of Embodiment 1〉

[0143] Next, the travel path of the first example described in Embodiment 1 will be described.

[0144] Figure 4 It is an explanatory diagram for explaining the travel path of the first example described in Embodiment 1.

[0145] Figure 4 It is the travel path existing within the drivable area 70 when the vehicle 60 equipped with the vehicle motion control device 2 in the vehicle system 1 travels at a constant speed on a curve (a curve with a changing peak curvature and different turning directions on the way: an S-shaped curve) composed of the first curve 81 and the second curve 82 with a peak curvature larger than that of the first curve 81.

[0146] And, Figure 4 The path for the vehicle 60 to travel within the drivable area 70 is shown. The dashed line is the path of the existing method A traveling in the center of the drivable area 70, the dash-dotted line is the path of the existing method B where the peak curvature of the first curve 81 and the second curve 82 is smaller than the peak curvature of the road shape, and the solid line is the travel path in the case of using Embodiment 1.

[0147] That is, in Embodiment 1, in this case, the peak curvature of the travel path when traveling on the first curve 81 is set to a curvature larger than the peak curvature of the road shape, and the peak curvature of the travel path when traveling on the second curve 82 is set to a curvature smaller than the peak curvature of the road shape.

[0148] Next, the curvature and the behavior of the vehicle when traveling on the travel path of the first example described in Embodiment 1 will be described.

[0149] Figures 5(a) to 5(d) It is an explanatory diagram for explaining the curvature and the behavior of the vehicle when traveling on the travel path of the first example described in Embodiment 1.

[0150] Figures 5(a) to 5(d) shown in Figure 4 the curvature and the behavior of the vehicle 60 while traveling at a certain speed on the curved road shown.

[0151] Fig. 5(a) shows the change in curvature corresponding to the passage of time, Fig. 5(b) shows the change in yaw rate corresponding to the passage of time, Fig. 5(c) shows the lateral acceleration corresponding to the passage of time, Fig. 5(d) shows the lateral jerk corresponding to the passage of time, the dashed line represents the existing method A, the dash-dotted line represents the existing method B, and the solid line represents Example 1.

[0152] As shown in Fig. 5(a), the peak curvature when the vehicle 60 travels on the first curved road 81 in Example 1 (the peak curvature of the first curved road 81 in Example 1) is larger than the peak curvature when the vehicle 60 travels on the first curved road 81 in the existing method A and the existing method B (the peak curvature of the first curved road in the existing method).

[0153] Therefore, as shown in Fig. 5(b) and Fig. 5(c), on the first curved road 81, the yaw rate and the lateral acceleration of Example 1 are larger than those of the existing method A and the existing method B.

[0154] By making the peak curvature of the first curved road 81 in Example 1 greater than the peak curvature of the first curved road 81 in the existing method, the degree of freedom of the driving path that can be generated in Example 1 is increased compared to the existing method A and the existing method B.

[0155] Thus, the peak curvature when the vehicle 60 travels on the second curved road 82 in Example 1 (the peak curvature of the second curved road 82 in Example 1) can be made smaller than the peak curvature when the vehicle 60 travels on the second curved road 82 in the existing method A and the existing method B (the peak curvature of the second curved road 82 in the existing method).

[0156] Therefore, as shown in Fig. 5(b), Fig. 5(c), and Fig. 5(d), on the second curved road 82, Example 1 can reduce the absolute values of the yaw rate, the lateral acceleration, and the lateral jerk compared to the existing method A and the existing method B.

[0157] Moreover, compared with the existing method A and the existing method B, Example 1 can increase the reduction amount of the yaw rate and the lateral acceleration on the second curved road 82 compared with the increase amount of the yaw rate and the lateral acceleration on the first curved road 81.

[0158] In addition, the absolute value of the lateral jerk near the inflection point of the curvature between the first curved road 81 and the second curved road 82 can be reduced.

[0159] Thus, Example 1 can reduce the behavior of the vehicle and improve the riding quality compared with the existing method A and the existing method B.

[0160] Next, the driving path of the second example described in Example 1 will be described.

[0161] Figure 6 It is an explanatory diagram for explaining the driving path of the second example described in Example 1.

[0162] Figure 6 It is the driving path existing within the drivable area 70 when the vehicle 60 equipped with the vehicle motion control device 2 travels on a curve (a curve with a changing peak curvature in the middle and the same turning direction) composed of the first curve 83 and the second curve 84 with a peak curvature larger than that of the first curve 83 at a constant speed.

[0163] And, Figure 6 The path for the vehicle 60 to travel within the drivable area 70 is shown. The dotted line is the path of the existing method A that travels in the center of the drivable area 70, the dashed-dotted line is the path of the existing method B where the peak curvature of the first curve 83 and the peak curvature of the second curve 84 are smaller than the peak curvature of the road shape, and the solid line is the driving path in the case of using Example 1.

[0164] That is to say, in Example 1, in this case, the peak curvature of the driving path when traveling on the first curve 83 is set to a curvature larger than the peak curvature of the road shape, and the peak curvature of the driving path when traveling on the second curve 84 is set to a curvature smaller than the peak curvature of the road shape.

[0165] Next, the curvature and the behavior of the vehicle when traveling on the driving path of the second example described in Example 1 will be described.

[0166] Figures 7(a) to 7(d) It is an explanatory diagram for explaining the curvature and the behavior of the vehicle when traveling on the driving path of the second example described in Example 1.

[0167] Figures 7(a) to 7(d) Shows during Figure 6 the curvature and the behavior of the vehicle 60 while traveling at a constant speed on the shown curve.

[0168] Figure 7(a) shows the change in curvature corresponding to the passage of time, Figure 7(b) shows the change in yaw rate corresponding to the passage of time, Figure 7(c) shows the lateral acceleration corresponding to the passage of time, Figure 7(d) shows the lateral jerk corresponding to the passage of time. The dotted line represents the existing method A, the dashed-dotted line represents the existing method B, and the solid line represents Example 1.

[0169] In Example 1, as Figures 7(a) to 7(d)As shown, for a curve where the peak curvature changes on the way and the turning directions are the same, the peak curvature of the driving path when driving on the first curve 83 with a small peak curvature is made larger than the peak curvature of the road shape, and the peak curvature of the driving path when driving on the second curve 84 with a large peak curvature is made smaller than the peak curvature of the road shape. Also, the peak curvature of the first curve 83 and the peak curvature of the second curve 84 are set to the same value and integrated into one curve with one peak curvature.

[0170] As shown in FIGS. 7(a), 7(b), and 7(c), the peak curvature when the vehicle 60 travels on a curve in Embodiment 1 (the peak curvature of the curve in Embodiment 1) can be smaller than the peak curvature when the vehicle 60 travels on a curve in the existing method A and the existing method B (the peak curvature of the curve in the existing method).

[0171] Therefore, as shown in FIG. 7(d), compared with the existing method A and the existing method B, Embodiment 1 can also reduce the absolute value of the lateral jerk.

[0172] In particular, as shown in FIG. 7(d), the lateral jerk generated between the first curve 83 and the second curve 84 (within the dashed box in the reference figure) can be made zero.

[0173] That is, it is possible to reduce the absolute value of the lateral jerk (make it zero) near the inflection point of the curvature between the first curve 81 and the second curve 82.

[0174] Thus, Embodiment 1 can reduce the behavior of the vehicle and improve the riding quality compared with the existing method A and the existing method B.

[0175] Here, an explanation is given for Figure 4 and Figure 6 the setting of the peak curvature of the driving path when traveling, for example, at the peak curvature of the first curve (small: 1 / 50) and the peak curvature of the second curve (large: 1 / 40). The peak curvature of the driving path when driving on the first curve becomes 1 / 47, and the peak curvature of the driving path when driving on the second curve becomes 1 / 42.

[0176] In addition, Figures 5(a) to 5(d) and Figures 7(a) to 7(d) are cases where the curvature change of the generated driving path is set to be linear. The curvature change of the generated driving path can also be set to be non - linear such as a sine half - wavelength decreasing curve or a cubic curve.

[0177] In this way, according to Embodiment 1, on a continuous curve where multiple curves with different curvatures are consecutive, it is also possible to reduce the peak of the curvature on the entire driving path and achieve a comfortable riding quality with small vehicle behavior.

[0178] Further, according to Embodiment 1, even when traveling on a continuous curve where there are restrictions on the distance between curves and the curvature of the curve changes midway, a driving path with small behavior of the vehicle during curve driving and a comfortable riding quality can be generated.

[0179] Embodiment 2

[0180] <Function blocks of the driving trajectory generation unit 22>

[0181] Next, the function blocks of the driving trajectory generation unit 22 described in Embodiment 2 will be described.

[0182] Figure 8 FIG. is an explanatory diagram for explaining the function blocks of the driving trajectory generation unit 22 described in Embodiment 2.

[0183] Compared with the driving trajectory generation unit 22 described in Embodiment 1, the difference of the driving trajectory generation unit 22 described in Embodiment 2 is that the path planning unit 22d is changed to a path candidate planning unit 22h, and a trajectory selection unit 22i is added.

[0184] Furthermore, the parts that are different from Figure 2 will be described here, and the description of the parts that are the same as Figure 2 is omitted.

[0185] The path candidate planning unit 22h inputs the driving condition information output from the information acquisition unit 22a, the number (information) of curves existing in the traveling direction of the vehicle output from the road determination unit 22b, the length, width, curvature (peak curvature), turning direction, starting point, end point, etc. of each detected curve, and the determination result (information) of whether the driving path is within the drivable area output from the path determination unit 22f, and generates a plurality of driving paths existing within the drivable area.

[0186] Furthermore, the plurality of driving paths generated by the path candidate planning unit 22h can be driving paths with different peak curvatures, or driving paths with different lengths of each section or different starting point coordinates of the first curve.

[0187] The speed planning unit 22g inputs the driving condition information and the plurality of driving paths output from the path candidate planning unit 22h, sets the speed (traveling speed) at each point existing on the plurality of driving paths, and outputs them as a plurality of driving trajectories to the trajectory selection unit 22i.

[0188] The trajectory selection unit 22i inputs the driving condition information and the plurality of driving trajectories output from the speed planning unit 22g, selects one driving trajectory that becomes the driving target of the vehicle, and outputs it as a driving trajectory to the driving control unit 23.

[0189] Here, the trajectory selection unit 22i selects a driving trajectory that matches the driving mode. Furthermore, the driving modes include the shortest time mode, the shortest distance mode, etc. For example, when the shortest time mode is set, the driving trajectory with the shortest moving time is selected from multiple driving trajectories, and when the shortest distance mode is set, the driving trajectory with the shortest moving distance is selected from multiple driving trajectories.

[0190] That is to say, multiple driving trajectories are set in the trajectory selection unit 22i, and the driving trajectory with the shortest moving time is selected from the multiple driving trajectories, and the driving trajectory with the shortest moving distance is selected from the multiple driving trajectories.

[0191] According to Embodiment 2, on a continuous curve where multiple curves with different curvatures are continuous, it is also possible to reduce the peaks of the curvature on the entire driving path and achieve a comfortable riding quality with small vehicle behavior.

[0192] In addition, according to Embodiment 2, when driving on a continuous curve where there are restrictions on the distance between curves and the curvature of the curve changes midway, it is also possible to generate a driving path with small vehicle behavior during curve driving and achieve a comfortable riding quality.

[0193] Furthermore, the present invention includes various modification examples and is not limited to the above-described embodiments. For example, the above embodiments are specific descriptions for explaining the present invention in an easy-to-understand manner and are not necessarily limited to all the configurations that have been described.

[0194] In addition, a part of the configuration of one embodiment can be replaced with a part of the configuration of another embodiment. In addition, a part of the configuration of another embodiment can be added to the configuration of one embodiment. In addition, for a part of the configuration of each embodiment, it can also be deleted, another part of the configuration can be added, or it can be exchanged with another part of the configuration.

[0195] Reference Signs

[0196] 1... Vehicle-mounted system, 11... Vehicle exterior communication device, 12... GNSS, 13... Map information storage unit, 14... Sensor, 15... HMI unit, 2... Vehicle motion control device, 21... Operation management unit, 22... Driving trajectory generation unit, 22a... Information acquisition unit, 22b... Road determination unit, 22c... Travelable area calculation unit, 22d... Path planning unit, 22e... Nearest neighbor point calculation unit, 22f... Path determination unit, 22g... Speed planning unit, 22h... Path candidate planning unit, 22i... Trajectory selection unit, 23... Driving control unit, 3... Power transmission system, 4... Braking system, 5... Steering system, 60... Vehicle, 70... Travelable area, 81, 83... First curve, 82, 84... Second curve.

Claims

1. A vehicle motion control device, characterized in that it has a travel trajectory generation unit, and the travel trajectory generation unit sets the curvature of the travel path when traveling on the curve with a smaller curvature among the first curve and the second curve connected to the first curve on the lane in the traveling direction of the vehicle to be larger than the curvature of the curve, and sets the curvature of the travel path when traveling on the curve with a larger curvature to be smaller than the curvature of the curve to generate a travel path, based on the information of the curvature of the first curve and the second curve on the lane in the traveling direction of the vehicle.

2. The vehicle motion control device according to claim 1, characterized in that the travel trajectory generation unit determines a curve with a fixed curvature or having a peak or an inflection point among a plurality of curves on the lane in the traveling direction of the vehicle as one curve.

3. The vehicle motion control device according to claim 1, characterized in that when the turning direction of the first curve is the same as the turning direction of the second curve, the travel trajectory generation unit determines whether it is impossible to achieve single-curving of the two curves, namely the first curve and the second curve, into one curve. When single-curving can be achieved, the travel trajectory generation unit single-curves the two curves, namely the first curve and the second curve, and makes the curvature of the first curve equal to the curvature of the second curve.

4. The vehicle motion control device according to claim 1, characterized in that when the number of curves is three or more, the travel trajectory generation unit obtains information related to the three or more curves to generate a travel path.

5. The vehicle motion control device according to claim 4, characterized in that when the number of curves is three or more and when a third curve connected to the second curve is newly detected while the vehicle is traveling on the first curve, the travel trajectory generation unit sets the curvature of the travel path when traveling on the curve with a smaller curvature among the second curve and the third curve to be larger than the curvature of the curve, and sets the curvature of the travel path when traveling on the curve with a larger curvature to be smaller than the curvature of the curve to generate a travel path.

6. The vehicle motion control device according to claim 1, characterized in that the travel trajectory generation unit sets the travel speed in such a way that it becomes below the upper limit value of the vehicle's behavior.

7. The vehicle motion control device according to claim 6, characterized in that the travel trajectory generation unit sets a plurality of travel trajectories and selects the travel trajectory with the shortest travel time from the plurality of travel trajectories.

8. The vehicle motion control device according to claim 6, characterized in that the travel trajectory generation unit sets a plurality of travel trajectories and selects the travel trajectory with the shortest travel distance from the plurality of travel trajectories.

9. A vehicle motion control method, characterized in that Based on the information about the curvature of the first curve and the second curve connected to the first curve on the lane in the traveling direction of the vehicle, the traveling path generation unit that generates the traveling path sets the curvature of the traveling path when traveling on the curve with the smaller curvature among the first curve and the second curve to be larger than the curvature of the curve, and sets the curvature of the traveling path when traveling on the curve with the larger curvature to be smaller than the curvature of the curve.

10. The vehicle motion control method according to claim 9, wherein in the traveling path generation unit, when the turning direction of the first curve is the same as the turning direction of the second curve, it is determined whether it is impossible to achieve the single-curving of the two curves, i.e., the first curve and the second curve, into one curve. When single-curving is achievable, the two curves, i.e., the first curve and the second curve, are single-curved, and the curvature of the first curve is made equal to the curvature of the second curve.

11. The vehicle motion control method according to claim 9, wherein in the traveling path generation unit, when the number of curves is three or more, information related to three or more curves is obtained to generate the traveling path.

12. The vehicle motion control method according to claim 11, wherein in the traveling path generation unit, when the number of curves is three or more and when a third curve connected to the second curve is newly detected while the vehicle is traveling on the first curve, the curvature of the traveling path when traveling on the curve with the smaller curvature among the second curve and the third curve is set to be larger than the curvature of the curve, and the curvature of the traveling path when traveling on the curve with the larger curvature is set to be smaller than the curvature of the curve to generate the traveling path.

13. The vehicle motion control method according to claim 9, wherein in the traveling path generation unit, the traveling speed is set so as to be below the upper limit value of the vehicle's behavior.

14. The vehicle motion control method according to claim 13, wherein in the traveling path generation unit, a plurality of traveling paths are set, and the traveling path with the shortest moving time is selected from the plurality of traveling paths.

15. The vehicle motion control method according to claim 13, wherein in the traveling path generation unit, a plurality of traveling paths are set, and the traveling path with the shortest moving distance is selected from the plurality of traveling paths.

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