Vehicle control method and vehicle control device

Abstract

To provide a vehicle control method and a vehicle control device capable of reducing lateral acceleration and lateral jerk generated in a vehicle when the vehicle returns to a target track before deviation.SOLUTION: A current position of a vehicle is acquired, a past position where the vehicle has traveled in the past is stored or estimated, it is determined whether or not the vehicle has deviated from a target trajectory, and when it is determined that the vehicle has deviated from the target trajectory, the target trajectory is updated to a return target trajectory which is a trajectory in which a lateral acceleration and a lateral jerk of the vehicle decrease and which passes through the current position and the past position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle control method and a vehicle control device. [Background technology]

[0002] A technology is known in which an evaluation function is generated that includes terms for evaluating the acceleration and jerk occurring in the front, rear, left, and right directions of the vehicle, and the evaluation function is converged to derive a driving trajectory while constraint conditions based on road boundaries are met (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-137410 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology disclosed in Patent Document 1 has a problem in that if the vehicle deviates from its driving path, the vehicle will undergo sudden steering to reduce the deviation between its current position and its driving path, which may result in increased lateral acceleration and lateral jerk in the vehicle.

[0005] The problem to be solved by the present invention is to provide a vehicle control method and a vehicle control device that can reduce the lateral acceleration and lateral jerk generated in the vehicle when the vehicle returns to the target trajectory before the deviation. [Means for solving the problem]

[0006] The present invention solves the above problem by acquiring the current position of the vehicle, storing or estimating past positions that the vehicle has traveled in the past, determining whether the vehicle has deviated from the target trajectory, and, if it is determined that the vehicle has deviated from the target trajectory, updating the target trajectory to a return target trajectory that reduces the lateral acceleration and lateral jerk of the vehicle and passes through the current and past positions. [Effects of the Invention]

[0007] According to the present invention, when the vehicle returns to the target trajectory before the deviation, the lateral acceleration and lateral jerk occurring in the vehicle can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing a vehicle control system including a vehicle control device according to the present invention. [Figure 2] FIG. 2 is a diagram for explaining an example of updating the target trajectory when the vehicle deviates from the target trajectory in this embodiment. [Figure 3] FIG. 3 is a diagram for explaining an example of each functional unit of the target trajectory generating unit according to this embodiment. [Figure 4] FIG. 4 is a diagram for explaining a situation in which the vehicle deviates from the target trajectory in this embodiment. [Figure 5] FIG. 5 is an example of a flowchart showing the procedure of the vehicle control method according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] FIG. 1 is a block diagram showing a vehicle control system including a vehicle control device according to the present invention. The vehicle control system 100 is an in-vehicle system that drives a vehicle using autonomous driving control. Autonomous driving control refers to autonomously controlling the driving behavior of a vehicle using a vehicle control device 1, and the driving behavior includes all driving behaviors such as acceleration, deceleration, starting, stopping, steering to the right or left, changing lanes, and pulling over. Furthermore, autonomously controlling driving behavior refers to the vehicle control device 1 controlling the driving behavior using a device in the vehicle. In other words, the vehicle control device 1 intervenes in and controls these driving behaviors within a predetermined range. Driving behaviors that are not intervened in are manually operated by the driver.

[0011] Vehicle control system 100 can be applied not only to vehicle driving under autonomous driving control, but also to assisting vehicle driving under manual driving by a driver. When vehicle control system 100 is applied to autonomous vehicle driving control, it can be applied to cases where both speed control and steering control are autonomously controlled, or where one of speed control and steering control is autonomously controlled and the other is manually controlled.

[0012] 1, the vehicle control system 100 includes a vehicle control device 1, a vehicle position detection device 2, a map DB 3, a detection device 4, and a drive mechanism 5. These devices included in the vehicle control system 100 are in-vehicle devices, are connected by a CAN or other in-vehicle LAN, and can exchange information with each other.

[0013] The vehicle position detection device 2 acquires the current position of the vehicle. The vehicle position detection device 2 is composed of, for example, a GPS unit, a gyro sensor, etc. The vehicle position detection device 2 detects radio waves transmitted from multiple satellite communications using the GPS unit to periodically acquire vehicle position information, and detects the current position of the vehicle based on the acquired vehicle position information, angle change information acquired from the gyro sensor, and vehicle speed acquired from the vehicle speed sensor. The vehicle position detection device 2 also acquires, for example, the position of the vehicle within the road (the lateral position of the vehicle in the left-right direction) as the current position of the vehicle. For example, the vehicle position detection device 2 recognizes the road surface around the vehicle from a camera image and estimates the lateral position of the vehicle within the road. The lateral position of the vehicle within the road is based, for example, on the position of the center of gravity of the vehicle. The detection information of the vehicle position detection device 2 is acquired by the vehicle control device 1 at predetermined time intervals.

[0014] The map DB3 is a high-precision three-dimensional map that describes road structures, including road surface markings that indicate lanes and destinations. The map DB3 is a database containing information used for generating a target trajectory and / or controlling vehicle travel. The map DB3 includes two-dimensional and / or three-dimensional position information for each map coordinate, road information for each map coordinate, lane boundary information, road attribute information, lane incline / descent information, lane identification information, destination lane information, facility information, and attribute information thereof. The road information includes information such as road width, curvature radius, road shoulder structures, road traffic regulations (speed limits, lane change permission / prohibition), road merging points, branching points, and locations where the number of lanes increases or decreases. The map DB3 may be stored in a readable state on a recording medium provided in the vehicle control device 1 or a server device, as well as in an on-board device.

[0015] The map DB3 also includes information on lane boundaries that indicate the boundaries between the lane in which the vehicle is traveling and other lanes. Lane boundaries exist on both the left and right sides of the vehicle's traveling direction. The form of the lane boundaries is not particularly limited, and examples thereof include road markings and road structures. Examples of lane boundaries that are road markings include lane boundary lines and center lines. Examples of road boundary structures include medians, guardrails, curbs, and side walls of tunnels or expressways. Note that lane boundaries are preset in the map DB3 for points where lane boundaries cannot be clearly identified (for example, within intersections). The preset lane boundaries are imaginary road boundaries and are not actually existing road markings or road structures.

[0016] The detection device 4 is a device that detects various types of information. The detection device 4 includes a sensor for detecting the driving environment around the vehicle. The driving environment around the vehicle includes objects around the vehicle. Examples of objects include lane boundaries on roads, zebra strips, center lines, road markings, median strips, guardrails, curbs, highway sidewalls, road signs, traffic lights, crosswalks, construction sites, accident sites, and traffic restrictions. Objects also include automobiles (other vehicles) other than vehicles, motorcycles, bicycles, and pedestrians. Objects also include obstacles that may affect the driving of the vehicle. The detection device 4 acquires the position, attitude (orientation), and speed of the detected objects. In this embodiment, the detection device 4 detects the position of obstacles in the vehicle's lane, the position and speed of a leading vehicle, and the position and speed of an oncoming vehicle.

[0017] The detection device 4 includes, for example, a camera. The detection information of the detection device 4 is acquired by the vehicle control device 1 at predetermined time intervals. The vehicle control device 1 acquires information about objects around the vehicle from the detection device 4. The camera recognizes objects around the vehicle from images. The detection device 4 may also include a distance measuring device for calculating the relative distance and relative speed between the vehicle and surrounding objects (preceding vehicles, obstacles). Examples of distance measuring devices include laser radar and LIDAR. A single vehicle may be provided with a plurality of such devices.

[0018] The detection device 4 includes a sensor for detecting the vehicle state of the vehicle. The vehicle state of the vehicle includes, for example, information on the vehicle speed and yaw rate of the vehicle. For example, these sensors are a vehicle speed sensor and a yaw rate sensor. The vehicle speed sensor measures the rotation speed of the drive train, such as the drive shaft, and detects the running speed of the vehicle (hereinafter also referred to as vehicle speed) based on this. The yaw rate sensor is a sensor that detects the attitude of the vehicle, such as the yaw rate, and is, for example, a gyro sensor. The detection information of the detection device 4 is acquired by the vehicle control device 1 at predetermined time intervals.

[0019] The vehicle control device 1 is a device that controls the running of a vehicle by controlling and cooperating with devices included in the vehicle control system 100. In this embodiment, the vehicle control device 1 realizes a vehicle control function using a processor 10. The processor 10 is a computer that includes a ROM that stores a program, a CPU that is an operating circuit that functions as the vehicle control device 1 by executing the program stored in the ROM, and a RAM that functions as an accessible storage device.

[0020] The processor 10 electronically controls the drive mechanism 5, which governs the operation of the vehicle. The processor 10 controls the drive mechanism 5 to drive the vehicle so that it follows a target trajectory at a target speed. The target trajectory is the trajectory along which the vehicle travels within a road. The drive mechanism 5 includes an electric motor and / or an internal combustion engine as a driving source, a power transmission device including a drive shaft and an automatic transmission that transmits output from these driving sources to the drive wheels, a drive device that controls the power transmission device, and a braking device that brakes the wheels. The processor 10 calculates the target speed, generates a control signal including a braking / driving force command value so that the vehicle speed becomes the target speed, and sends the control signal to the drive mechanism 5. The drive device and braking device perform braking / driving control of the vehicle based on the control signal obtained from the processor 10.

[0021] The processor 10 controls the steering device included in the drive mechanism 5 so that the vehicle travels while maintaining a predetermined lateral position relative to the target trajectory. The steering device is equipped with a steering actuator. The steering actuator includes a motor attached to the steering column shaft, etc. The processor 10 generates a target trajectory, generates a control signal including a steering angle command value so that the vehicle follows the target trajectory, and sends the control signal to the drive mechanism 5. The steering device performs steering control of the vehicle based on the control signal obtained from the processor 10. Below, details of each functional unit of the processor 10 according to this embodiment will be described.

[0022] The processor 10 includes, as functional blocks, a current position acquisition unit 11, a past position storage unit 12, a lane boundary generation unit 13, a target trajectory generation unit 14, a target speed generation unit 15, a trajectory tracking control unit 16, and a speed tracking control unit 17. The processor 10 of this embodiment executes each function through cooperation between the above-mentioned hardware and software for realizing each function or executing each process.

[0023] The current position acquisition unit 11 executes a position acquisition process to acquire the current position of the vehicle from the vehicle position detection device 2. The position acquisition process is executed at a fixed cycle. The fixed cycle is a predetermined sampling time (for example, about a few tenths of a second). The current position of the vehicle is acquired when the vehicle deviates from the target trajectory, and is used to generate a return target trajectory.

[0024] The past position storage unit 12 stores past positions where the vehicle has traveled in the past. For example, the past position storage unit 12 stores the current position acquired by the current position acquisition unit 11 at a predetermined time in the past as the past position. When the current position is acquired at regular intervals, the past position storage unit 12 may store the current positions acquired at each regular interval in chronological order, or may store the current position acquired at the previous interval (the previous sampling time). For example, the past position storage unit 12 stores the current position acquired when the vehicle is traveling on a target trajectory during normal driving as the past position. Furthermore, the past position storage unit 12 is not limited to storing past positions, and may estimate the past position based on the current position of the vehicle, the current vehicle speed of the vehicle, and the current yaw rate of the vehicle. For example, when the vehicle deviates from the target trajectory, the past position storage unit 12 estimates the past position based on the current position of the vehicle, the current vehicle speed of the vehicle, and the current yaw rate of the vehicle at the time the vehicle deviated from the target trajectory.

[0025] The past position may also be a position that is a predetermined distance or more away from the current position. The predetermined distance is also referred to as a predetermined previous distance. For example, the predetermined distance is a distance at which steering control can be performed. The predetermined distance may also be a distance at which yawing resonance can be avoided. The predetermined distance may also be a distance that is shorter than a predetermined departure determination distance, which will be described later. For example, the predetermined distance is a predetermined departure determination distance. The predetermined distance may also be set according to the amount of departure. For example, the greater the amount of departure, the greater the predetermined distance.

[0026] The lane boundary generation unit 13 generates the boundary of the lane along which the vehicle will travel, based on the current position of the vehicle and information from the map DB3. The lane boundary generation unit 13 acquires lane information around the vehicle. For example, the lane boundary generation unit 13 acquires lane information about the lane along which the vehicle is traveling. The lane information includes the position of lane boundary lines and the width of the lane. The lane boundary generation unit 13 may also acquire lane information including the lane boundary lines of the lane from an image of the area around the vehicle captured by the detection device 4. The lane boundary generation unit 13 generates the boundary of the lane along the lane boundary lines based on the acquired lane information.

[0027] The target trajectory generation unit 14 generates a target trajectory (a target trajectory during normal driving) based on the boundary of the road located ahead of the vehicle. The target trajectory during normal driving is a target trajectory for the vehicle to travel within the road. Specifically, the target trajectory generation unit 14 generates a target trajectory within the road. For example, the target trajectory generation unit 14 generates a target trajectory along the center line between the left and right boundaries of the road. The target trajectory is expressed as a plurality of points (trajectory points) that the vehicle should reach within a predetermined time or a predetermined section, arranged in order from closest to the vehicle. A trajectory point is a position that the vehicle should reach at a predetermined sampling time (for example, approximately a few tenths of a second). A trajectory point is indicated by a coordinate position in X and Y coordinates. That is, the target trajectory is expressed by the coordinate position of each trajectory point. Furthermore, information on the target speed and target acceleration is expressed by the interval between the trajectory points.

[0028] While the vehicle is traveling so as to follow the target trajectory (target trajectory during normal traveling), the target trajectory generation unit 14 determines whether the vehicle has deviated from the target trajectory based on the current position of the vehicle and the target trajectory. Specifically, the target trajectory generation unit 14 periodically acquires the current position of the vehicle and compares the current position of the vehicle with the position of the target trajectory. For example, the target trajectory generation unit 14 determines that the vehicle has deviated from the target trajectory when the amount of deviation of the vehicle from the target trajectory exceeds a predetermined deviation threshold. The deviation amount is, for example, the distance between the current position of the vehicle and the target trajectory. The predetermined deviation threshold is a value obtained by multiplying the allowable value of the deviation amount by a predetermined percentage (<1), for example, a predetermined deviation judgment distance. In other words, the predetermined deviation judgment distance is a distance used to determine whether the vehicle has deviated from the target trajectory. The predetermined deviation judgment distance is, for example, the distance from the center of gravity of the vehicle to the side of the vehicle. The predetermined deviation judgment distance is also a distance at which lateral acceleration and lateral jerk greater than or equal to the allowable values ​​may occur when travel control is performed to follow the target trajectory during normal traveling. The allowable values ​​of the lateral acceleration and lateral jerk are set in advance through experiments or the like.

[0029] When the target trajectory generation unit 14 determines that the vehicle has deviated from the target trajectory (the target trajectory during normal driving), it generates a new target trajectory (also referred to as a return target trajectory) within the roadway for the vehicle to return to a position on the target trajectory before the deviation (the target trajectory during normal driving), and updates the target trajectory to the return target trajectory. The return target trajectory is a trajectory that reduces the lateral acceleration and lateral jerk of the vehicle over a predetermined time period or a predetermined section, and passes through the current position and past positions. The return target trajectory is expressed as a sequence of multiple trajectory points that the vehicle should reach from the current position of the vehicle, with the past and current positions of the vehicle each being one of the trajectory points. Here, an example of updating the target trajectory when the vehicle deviates from the target trajectory in this embodiment will be described with reference to FIG. 2. FIG. 2 is a diagram for explaining an example of updating the target trajectory when the vehicle deviates from the target trajectory in this embodiment. As shown in FIG. 2, the roadway R is the area between the left boundary Lb and the right boundary Rb. Furthermore, the target trajectory T (Ta, Tb, Tc) is generated so as to pass through the track between the left boundary Lb and the right boundary Rb. The target trajectory T is represented by the positions of each trajectory point X[0], X[1], X[2], ..., X[N] and the links connecting each adjacent trajectory point. In Fig. 2, the positions of the trajectory points X[0] and X[1] are the positions of the trajectory point that is the starting point of the trajectory and the position of the second trajectory point, respectively, and are the past position X of the vehicle. p0 and current position X p1 It is represented as:

[0030] In FIG. 2, scenes at sampling times k=0, 1, and 2 are shown in chronological order from the left. The scene at sampling time k=0 is a scene in which the vehicle V is following the target trajectory Ta under normal conditions. The scene at sampling time k=1 is a scene in which the vehicle V deviates from the target trajectory Ta. In the scene at sampling time k=1, the current position X at the previous sampling time (k=0) is p1 is the vehicle's past position X p0 The current position of the vehicle is X p1 At this time, the target trajectory generating unit 14 calculates the position X[0] and the position X[1] of the trajectory point from the past position X p0 and current position X p1A target trajectory Tb is generated so that:

[0031] The scene at sampling time k=2 is the scene at the sampling time next to sampling time k=1. In the scene at sampling time k=2, the current position X at the previous sampling time (k=1) p1 is the vehicle's past position X p0 The current position of the vehicle is X p1 At this time, the target trajectory generating unit 14 calculates the position X[0] and the position X[1] of the trajectory point from the past position X p0 and current position X p1 A target trajectory Tc is generated so that

[0032] Next, the fact that the target return trajectory is a trajectory that reduces the lateral acceleration and lateral jerk of the vehicle will be described. The target return trajectory is a trajectory that reduces the lateral acceleration and lateral jerk of the vehicle while satisfying the condition that it passes through the current position and the past position as described above. Specifically, the target trajectory generation unit 14 calculates an evaluation function that includes terms for evaluating the lateral acceleration and lateral jerk of the vehicle, and generates a target trajectory that minimizes the evaluation function. The evaluation function is expressed as the sum of the integral values ​​of the lateral acceleration and lateral jerk. Each integral value is weighted at a predetermined rate. As a result, the target return trajectory is generated as a smooth curved trajectory.

[0033] Here, an example of each process of the target trajectory generating unit according to this embodiment will be described with reference to Figs. 3 and 4. Fig. 3 is a diagram for explaining an example of each functional unit of the target trajectory generating unit according to this embodiment. Fig. 3 shows a block diagram illustrating an example of each functional unit of the target trajectory generating unit. Fig. 4 is a diagram for explaining a scene in this embodiment where the vehicle deviates from the target trajectory. As shown in Fig. 4, the road R is the area between the left boundary Lb and the right boundary Rb. Furthermore, the target trajectory Ta is the target trajectory during normal driving, and is generated so as to pass between the left boundary Lb and the right boundary Rb. The target trajectory Tb is the return target trajectory when the vehicle deviates from the target trajectory Ta. The target trajectory Tb is represented by the positions X[0], X[1], X[2], ..., X[N] of each trajectory point and the links connecting adjacent trajectory points. In Fig. 4, the current position and past positions of the vehicle are represented by X[0], X[1], X[2], ..., X[N]. p1 and X p0 The horizontal position of each orbital point is expressed as α[0], α[1], α[2], α[N]. For example, the horizontal positions of the orbital points α[0] and α[1] are expressed as α p0 (0<α p0 <1), α p1 (0<α p1 <1).

[0034] 3, the target trajectory generating unit 14 includes, as functional units, a lateral position converting unit 140, a convergence calculation unit 141, and a trajectory generating unit 142. The lateral position converting unit 140 receives the current position X of the vehicle from the current position acquiring unit 11. p1 (x p1 , y p1 ) from the past position storage unit 12. p0 (x p0 , y p0 The past position storage unit 12 may store the current position acquired by the current position acquisition unit 11 at a predetermined time in the past as the past position, or may acquire the current vehicle speed (V) and yaw rate (γ) of the vehicle and estimate the past position based on the current vehicle position, the current vehicle speed and yaw rate of the vehicle. In addition, the lateral position conversion unit 140 acquires the positions X L (x L, y L ), X R (x R , y R ) to get the

[0035] The horizontal position conversion unit 140 converts the current position X p1 (x p1 , y p1 ) to horizontal position α p1 (0<α p1 <1). The horizontal position conversion unit 140 converts the past position X p0 (x p0 , y p0 ) to horizontal position α p0 (0<α p0 The horizontal position conversion unit 140 converts the position X of the boundary between the left and right lanes into L (x L , y L ), X R (x R , y R ) to horizontal position α L , α R The horizontal position conversion unit 140 outputs the converted horizontal positions to the convergence calculation unit 141.

[0036] The convergence calculation unit 141 performs convergence calculation of an evaluation function including terms for evaluating the lateral acceleration and lateral jerk of the vehicle. For example, the convergence calculation unit 141 calculates the lateral position of each trajectory point by solving the following equation (1). Q is the evaluation function, and α is the lateral position of the trajectory point representing the target trajectory. The constraint condition is α L <α<α R , α[1]=α p1 , α[0]=α p0 The horizontal positions of the orbit points α[0] and α[1] are the horizontal positions of the starting point of the return target orbit and the second orbit point of the return target orbit, respectively.

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[0037] As described above, the convergence calculation unit 141 executes the convergence calculation to calculate the lateral positions α[0], α[1], α[2]...α[N] of each trajectory point of the target trajectory. The convergence calculation unit 141 outputs the calculated lateral positions α[0], α[1], α[2]...α[N] of each trajectory point to the trajectory generation unit 142. The trajectory generation unit 142 generates a target trajectory based on the lateral positions α[0], α[1], α[2]...α[N] of each trajectory point. In the generated target trajectory, the position of each trajectory point is expressed by an X coordinate and a Y coordinate. The trajectory generation unit 142 outputs the generated target trajectory to the trajectory tracking control unit 16.

[0038] Furthermore, the target trajectory generating unit 14 may calculate an evaluation function including a term for evaluating the deviation between a past target trajectory and a current target trajectory, using a target trajectory generated in the past as the past target trajectory, and perform a convergence calculation of the calculated evaluation function. The target trajectory generating unit 14 generates a target trajectory that reduces the deviation between the past target trajectory and the current target trajectory. For example, the convergence calculation unit 141 calculates the lateral position α of each trajectory point by solving the following equation (2): Q E is an evaluation function that includes a term that evaluates the deviation between the past target trajectory and the current target trajectory, and α Z is the lateral position of the trajectory point representing the past target trajectory. In equation (2), the explanation of equation (1) is used as appropriate.

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[0039] As described above, the return target trajectory is a trajectory that passes through the past position and the current position, and therefore, a target trajectory from the current position onward is generated based on the trajectory from the past position to the current position. That is, the return target trajectory is generated based on the curvature of the trajectory that the vehicle has actually traveled (current traveling curvature). Therefore, the lateral acceleration and lateral jerk generated in the vehicle traveling along the return target trajectory are reduced. In addition, in this embodiment, the return target trajectory may be a trajectory with an inconstant curvature change. The target trajectory generation unit 14 generates a trajectory with a variable curvature change that reduces the curvature change and the curvature. For example, the target trajectory generation unit 14 calculates the most recent curvature and generates a trajectory based on the most recent curvature, thereby reducing the curvature change of the trajectory. In this embodiment, by generating a trajectory with a small curvature change and the curvature, it is possible to reduce the lateral acceleration and lateral jerk more effectively than a trajectory with a constant curvature change, such as a clothoid curve.

[0040] The target speed generating unit 15 generates a target speed based on the target trajectory generated by the target trajectory generating unit 14 and detection information obtained by detecting the running environment around the vehicle. The running environment around the vehicle includes, for example, a preceding vehicle, obstacles, etc.

[0041] The trajectory tracking control unit 16 executes steering control of the vehicle so that the vehicle follows the target trajectory. The trajectory tracking control unit 16 controls the steering device so that the vehicle travels while maintaining a predetermined lateral position with respect to the target trajectory. Specifically, the trajectory tracking control unit 16 generates a control signal including a steering angle command value so that the vehicle follows the target trajectory, and sends the control signal to the drive mechanism 5.

[0042] Furthermore, when it is determined that the vehicle has deviated from the target trajectory, the trajectory tracking control unit 16 executes steering control so that the vehicle follows the return target trajectory. The trajectory tracking control unit 16 controls the steering device so that the vehicle travels while maintaining a predetermined lateral position with respect to the return target trajectory.

[0043] The speed tracking control unit 17 executes braking / driving control of the vehicle so that the vehicle speed becomes the target speed. The speed tracking control unit 17 controls the drive device and the braking device so that the vehicle travels while maintaining the target speed. The speed tracking control unit 17 generates a control signal including a braking / driving force command value so that the vehicle speed becomes the target speed, and sends the control signal to the drive mechanism 5.

[0044] Next, a procedure by which the vehicle control device 1 executes vehicle control according to this embodiment will be described with reference to Fig. 5. Fig. 5 is an example of a flowchart showing the procedure of the vehicle control method according to this embodiment. In this embodiment, when the vehicle starts traveling along the target trajectory, the processor 10 starts the flow from step S10.

[0045] In step S10, the processor 10 acquires the current position of the vehicle. In step S20, the processor 10 determines whether the vehicle has deviated from the target trajectory. If it is determined that the vehicle has deviated from the target trajectory, the processor 10 proceeds to step S30. If it is determined that the vehicle has not deviated from the target trajectory, the processor 10 returns to step S10 and repeats the subsequent flow.

[0046] In step S30, processor 10 acquires the current position of the vehicle. In step S40, processor 10 generates a target trajectory (return target trajectory) for returning the vehicle to a position on the target trajectory during normal driving. In step S50, processor 10 generates a target speed for the vehicle to travel on the return target trajectory. In step S60, processor 10 generates a steering angle command value for the vehicle to follow the return target trajectory. In step S70, processor 10 generates braking / driving force command values ​​for the vehicle speed to follow the target speed. Processor 10 outputs the generated command value to drive mechanism 5, and then ends the control flow. Drive mechanism 5 performs speed control and steering control based on the command value.

[0047] As described above, in the vehicle control method and vehicle control device according to this embodiment, the processor executes steering control of the vehicle so that the vehicle follows a target trajectory, acquires the current position of the vehicle, stores or estimates past positions of the vehicle, determines whether the vehicle has deviated from the target trajectory, and, if it determines that the vehicle has deviated from the target trajectory, generates a return target trajectory that passes through the current and past positions and reduces the lateral acceleration and lateral jerk of the vehicle, and updates the target trajectory to the return target trajectory. This makes it possible to further reduce the lateral acceleration and lateral jerk generated in the vehicle when the vehicle returns to the target trajectory before the deviation.

[0048] In the vehicle control method and vehicle control device according to this embodiment, the processor calculates an evaluation function including terms for evaluating the lateral acceleration and lateral jerk of the vehicle, and performs a convergence calculation of the evaluation function to generate a return target trajectory that minimizes the evaluation function, thereby more accurately reducing the lateral acceleration and lateral jerk occurring in the vehicle.

[0049] In the vehicle control method and vehicle control device according to this embodiment, the processor stores the current position acquired at a predetermined time in the past as the past position, thereby generating a smooth target trajectory that connects the current position with the positions where the vehicle has actually traveled in the past.

[0050] Furthermore, in the vehicle control method and vehicle control device according to this embodiment, the processor estimates the past position based on the current position, the vehicle speed, and the vehicle yaw rate, thereby making it possible to generate a smooth target trajectory that connects the past positions of the vehicle with the current position, even if there is no record of the actual past positions of the vehicle.

[0051] Furthermore, in the vehicle control method and vehicle control device according to this embodiment, the processor calculates an evaluation function that further includes a term for evaluating the deviation between a previously generated target trajectory and a return target trajectory, and performs a convergence calculation of the evaluation function to generate a return target trajectory that reduces the deviation. This makes it possible to generate a target trajectory that reduces the deviation from the past target trajectory.

[0052] In the vehicle control method and vehicle control device according to this embodiment, the processor stores or estimates past positions that are at least a predetermined distance from the current position, where the predetermined distance is a distance at which steering control can be performed, a distance at which yaw resonance can be avoided, or a distance shorter than a predetermined deviation judgment distance, where the predetermined deviation judgment distance is a distance for determining whether the vehicle has deviated from the target trajectory. This makes it possible to more accurately reduce the lateral acceleration and lateral jerk generated in the vehicle.

[0053] In the vehicle control method and vehicle control device according to this embodiment, the processor determines that the vehicle has deviated from the target trajectory when the distance between the current position and the target trajectory is greater than a predetermined deviation determination distance, thereby making it possible to determine that the vehicle has deviated from the target trajectory.

[0054] It should be noted that the above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above-described embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Explanation of symbols]

[0055] 100...Vehicle control system 1...Vehicle control device 2...Vehicle position detection device 3. Map database 4. Detection device 5...Drive mechanism 10...Processor 11…Current position acquisition unit 12...Past position memory section 13...Runway boundary generation section 14…Target trajectory generation unit 15...Target speed generation section 16...Trajectory tracking control unit 17...Speed ​​tracking control section

Claims

1. 1. A vehicle control method executed by a processor that performs steering control of a vehicle so that the vehicle follows a target trajectory, comprising: The processor: Obtaining the current location of the vehicle; storing or estimating past positions of the vehicle; determining whether the vehicle has deviated from the target trajectory; a vehicle control method for updating the target trajectory to the return target trajectory when it is determined that the vehicle has deviated from the target trajectory, the return target trajectory being a trajectory that reduces the lateral acceleration and lateral jerk of the vehicle and that passes through the current position and the past position;

2. 2. The vehicle control method according to claim 1, The processor: calculating an evaluation function including terms for evaluating the lateral acceleration and lateral jerk of the vehicle; A vehicle control method for generating the return target trajectory that minimizes the evaluation function by performing a convergence calculation of the evaluation function.

3. 3. A vehicle control method according to claim 1 or 2, The processor: A vehicle control method for storing the current position acquired at a predetermined time in the past as the past position.

4. 3. A vehicle control method according to claim 1 or 2, The processor: A vehicle control method for estimating the past position based on the current position, the speed of the vehicle, and the yaw rate of the vehicle.

5. 3. The vehicle control method according to claim 2, The processor: calculating the evaluation function further including a term for evaluating a deviation between the previously generated target trajectory and the return target trajectory; A vehicle control method for generating the return target trajectory in which the deviation is reduced by performing a convergence calculation of the evaluation function.

6. 3. A vehicle control method according to claim 1 or 2, The processor: storing or estimating the past position that is at least a predetermined distance away from the current position; the predetermined distance is a distance at which the steering control can be performed, a distance at which yawing resonance can be avoided, or a distance that is shorter than a predetermined departure determination distance, The vehicle control method, wherein the predetermined deviation determination distance is a distance for determining whether the vehicle has deviated from the target trajectory.

7. 3. A vehicle control method according to claim 1 or 2, The processor: A vehicle control method for determining that the vehicle has deviated from the target trajectory when the distance between the current position and the target trajectory is greater than a predetermined deviation determination distance.

8. A vehicle control device including a processor that executes steering control of a vehicle so that the vehicle follows a target trajectory, The processor: Obtaining the current location of the vehicle; storing or estimating past positions of the vehicle; determining whether the vehicle has deviated from the target trajectory; a vehicle control device that, when it is determined that the vehicle has deviated from the target trajectory, generates a return target trajectory that reduces the lateral acceleration and lateral jerk of the vehicle and passes through the current position and the past position, and updates the target trajectory to the return target trajectory.

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