Path generation device and driving assistance control device

Abstract

The vehicle path generation device (110) includes a target path generation unit (101) that generates a target path for the vehicle, a lateral position correction setting unit (102) that sets a lateral correction amount relative to the target path, i.e., a lateral position correction amount, and a target path correction unit (103) that calculates and corrects the path based on the target path and the lateral position correction amount.

Description

Technical Field

[0001] This application relates to a path generation device for generating a path for a vehicle to travel, and a driving assistance control device using the path generation device. Background Technology

[0002] Previously, control technologies related to automatic steering of vehicles were known. For example, Patent Document 1 discloses a lane keeping assist device that can perform lane keeping assist control to assist steering when the vehicle is driving in a lane.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-217707 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In driving assistance control systems such as lane keeping systems, the steering angle is typically determined by feedback control based on the deviation between the target path calculated by sensors based on road information detected ahead of the vehicle and the vehicle's actual driving path. When the deviation from the target driving position changes discontinuously, such as when the automatic steering system is activated, or when driving assistance control begins, the vehicle may not be able to follow the target path. Furthermore, in conventional control systems that rely on feedback of lateral position deviation, the steering angle command changes abruptly at the start of control, potentially causing swaying along the vehicle's trajectory.

[0008] This application was made to solve the aforementioned problems, and its purpose is to provide a path generation device that can generate a corrected path that a vehicle can follow by correcting the target path according to the vehicle's driving state.

[0009] Technical means for solving technical problems

[0010] The path generation apparatus disclosed in this application includes: a target path generation unit that generates a target path for a vehicle, a lateral position correction setting unit that sets a lateral correction amount relative to the target path, i.e., a lateral position correction amount, and a target path correction unit that calculates and corrects the path based on the lateral position correction amount.

[0011] Invention Effects

[0012] According to the path generation apparatus disclosed in this application, by correcting the target path based on the vehicle's driving state, a corrected path can be generated that does not change abruptly in steering angle command and that the vehicle can follow. Attached Figure Description

[0013] Figure 1 This is a diagram showing the structure of a vehicle equipped with a driving assistance control device including the path generation device according to Embodiment 1.

[0014] Figure 2 This is a block diagram showing a driving assistance control device that includes the path generation device according to Embodiment 1.

[0015] Figure 3 This is a block diagram illustrating the hardware structure of a driving assistance control device that includes the path generation device according to Embodiment 1.

[0016] Figure 4 This is a diagram illustrating the operation of the target path correction unit of the path generation apparatus according to Embodiment 1.

[0017] Figure 5 This is a diagram illustrating an example of a driving scenario that is controlled by the driving assistance control device according to Embodiment 1.

[0018] Figure 6 It means Figure 5 The figure shows the simulation results of previous vehicle driving control actions in the driving scenario.

[0019] Figure 7 It is used for explanation Figure 5 A diagram illustrating the operation of the target path correction unit of the path generation device according to Embodiment 1 in a driving scenario.

[0020] Figure 8 It means including Figure 5 A diagram showing the simulation results of the driving assistance control device of the path generation device involved in Implementation 1 in a driving scenario.

[0021] Figure 9 This is a block diagram of a modified example of the driving assistance control device according to Embodiment 1.

[0022] Figure 10 This is a diagram illustrating an example of a driving scenario in a variation of Embodiment 1 where the driving assistance control device becomes the control object.

[0023] Figure 11 This is a diagram showing the simulation results of the operation of a variation of Embodiment 1, namely the driving assistance control device.

[0024] Figure 12 This is a block diagram showing a driving assistance control device that includes the path generation device according to Embodiment 2.

[0025] Figure 13 This is a diagram illustrating an example of a driving scenario that is controlled by the driving assistance control device involved in the implementation.

[0026] Figure 14 This is a diagram showing the simulation results of a driving scenario that is the control object of the driving assistance control device according to Embodiment 2.

[0027] Figure 15 This is a block diagram illustrating the driving assistance control device according to Embodiment 3.

[0028] Figure 16 This is a diagram illustrating the operation of the driving assistance control device according to Embodiment 3.

[0029] Figure 17 This is a diagram showing the simulation results of a driving scenario that is the control object of the driving assistance control device involved in Embodiment 3. Detailed Implementation

[0030] The following description, based on the accompanying drawings, details the path generation device and driving assistance control device for the vehicle according to the embodiments. In each drawing, the same or equivalent parts are labeled with the same reference numerals.

[0031] Implementation method 1.

[0032] Figure 1 An example of a structure relating to the steering of a vehicle in connection with the driving assistance control device 100 for implementing vehicle steering.

[0033] The vehicle (also referred to as the vehicle itself) 10 is equipped with a speed detector 1, a yaw rate detector 2, a camera 3, a driver assistance ECU (Electronic Control Unit) 4, a steering ECU 5, a steering mechanism 6, and steering wheels 7. The speed detector 1 detects the speed of the vehicle 10 and sends it to the driver assistance ECU 4. The yaw rate detector 2 detects the yaw rate of the vehicle 10 and sends it to the driver assistance ECU 4. The camera 3 captures images of the white lines painted on the road indicating lane areas and sends the information about the white lines in front of the vehicle 10 to the driver assistance ECU 4.

[0034] The driving assistance ECU 4 performs the functions of the driving assistance control device 100 described later. Based on the vehicle speed 10 obtained from the vehicle speed detector 1, the yaw rate of the vehicle 10 obtained from the yaw rate detector 2, and the information about the white line in front of the vehicle 10 obtained from the camera 3, the driving assistance ECU 4 sends control commands to the steering ECU 5. The steering ECU 5 controls the movement of the steering mechanism 6 according to the control commands from the driving assistance ECU 4. The steering wheels 7 determine their angle relative to the vehicle 10 based on the movement of the steering mechanism 6, controlling the lateral movement of the vehicle 10.

[0035] Figure 2This is a functional block diagram illustrating the driving assistance control device 100 of the vehicle involved in Embodiment 1.

[0036] The driving assistance control device 100 consists of a path generation device 110 and a steering amount calculation unit 104.

[0037] The path generation device 110 calculates the target path ahead of the vehicle based on the vehicle speed detected by the vehicle speed detector 1, the yaw rate detected by the yaw rate detector 2, and the road information ahead of the vehicle detected by the camera 3.

[0038] Steering angle calculation unit 104 generates steering angle command δ for following the target path. * And output it to steering ECU 5. Steering ECU 5 then outputs it according to the steering angle command δ. * The actuator that drives the vehicle's steering is controlled by the vehicle's steering angle δ and the steering angle command δ. * Consistent.

[0039] The vehicle path generation device 110 includes a target path generation unit 101, a lateral position correction amount setting unit 102, and a target path correction unit 103.

[0040] The target path generation unit 101 calculates the target path based on the information detected by the vehicle speed detector 1, the yaw rate detector 2 and the camera 3, and inputs it into the target path correction unit 103.

[0041] The lateral position correction setting unit 102 determines the lateral position correction amount of the target path and inputs it into the target path correction unit 103 and the steering amount calculation unit 104.

[0042] The target path correction unit 103 corrects the target path calculated by the target path generation unit 101 based on the lateral position correction amount, and inputs the corrected path information into the steering amount calculation unit 104.

[0043] The structures of the path generation device 110 and the driving assistance control device 100 described above can be configured using a computer, and each of the above structures can be implemented by executing a program on a computer. That is, Figure 2 The target path generation unit 101, lateral position correction setting unit 102, target path correction unit 103, and steering amount calculation unit 104 of the vehicle path generation device 110 shown are, for example, composed of... Figure 3The processor 1000 shown is implemented in this way. For the processing circuit 1000, a CPU (Central Processing Unit), DSP (Digital Signal Processor), etc., are used, and the functions of the above-described structures are implemented by executing programs stored in the storage device 1001. The same applies to other embodiments.

[0044] Next, in Figure 2 The operation of each part of the vehicle path generation device 110 and driving assistance control device 100 is described in detail.

[0045] In the target path generation unit 101, based on the white line information in front of the vehicle 10 obtained from the camera 3, the lateral position C0 of the white lines relative to the vehicle is obtained for each of the left and right white lines. R C0 L Posture angle C1 R C1 L Path curvature C2 R C2 L .

[0046] When the target path is, for example, the center of the left and right white lines, the lateral position C0, attitude angle C1, and path curvature C2 relative to the target path of the vehicle 10 are calculated by the following equations (1), (2), and (3).

[0047] [Mathematical Expression 1]

[0048]

[0049] [Mathematical Expression 2]

[0050]

[0051] [Mathematical Expression 3]

[0052]

[0053] The target path can also be determined based on driving conditions, by using the line whose lateral position C0 is close to either the left or right as shown in equation (4). Here, C00 is a constant.

[0054] [Mathematical Expression 4]

[0055]

[0056] In the lateral position correction setting unit 102, the first lateral position correction amount and the second lateral position correction amount are set at arbitrary timings based on driving conditions and other factors, independently of the target path generated by the target path generation unit 101. The step input from the first lateral position correction amount to the second lateral position correction amount is used as the lateral position correction amount y. ofst To output.

[0057] In the target path correction unit 103, the lateral position correction amount y set by the lateral position correction amount setting unit 102 is used. ofst Generate the correction path. The target lateral position y of the correction path. flt Target lateral velocity vy flt Target lateral acceleration ay flt The lateral position correction amount y can be used ofst and filter F dref (s), and is obtained through the following formulas (5), (6), and (7). s is the Laplace operator.

[0058] [Mathematical Expression 5]

[0059] y flt =F dref (s)y ofst ···(5)

[0060] [Mathematical Expression 6]

[0061] v yflt =sy flt =s(F dref (s)y ofst (6)

[0062] [Mathematical Expression 7]

[0063] a yflt =s 2 y flt =s 2 (F dref (s)y ofst )···(7)

[0064] In equation (5) above, by using filter F dref The input of (s) is set as a step input from the first lateral position correction to the second lateral position correction, i.e., the lateral position correction y. ofst It can generate a time history from the convergence of the first lateral position correction to the second lateral position correction as the correction path for the target path.

[0065] Figure 4 This describes an example of the operation of the target path correction unit 103. Figure 4The dashed lines representing the motion characteristics shown in the first layer (upper section) indicate the step input from the first lateral position correction to the second lateral position correction, i.e., the lateral position correction y. ofst The solid lines represent the time history of the lateral position of the correction path. The solid lines representing the motion characteristics shown in layer 2 (middle section) of this figure represent the time history of the lateral velocity of the correction path. The solid lines representing the motion characteristics shown in layer 3 (lower section) of this figure represent the lateral acceleration of the correction path.

[0066] Furthermore, using equations (5), (6), and (7), since the corrected path and the target path are in the same form as equations (1), (2), and (3), the lateral position C0', attitude angle C1', and curvature C2' of the corrected path relative to the vehicle 10 are calculated by the following equations (8), (9), and (10).

[0067] [Mathematical Expression 8]

[0068] C0′=C0+y flt ···(8)

[0069] [Mathematical Expression 9]

[0070]

[0071] [Mathematical Expression 10]

[0072]

[0073] In equations (9) and (10), V represents the speed of vehicle 10.

[0074] Filter F dref (s) Use a second-order low-pass filter, for example, as shown in equation (11). ζ is the attenuation coefficient, and ωn is the frequency.

[0075] [Mathematical Expression 11]

[0076]

[0077] The moving average filter can be used for filter F dref (s). Equation (12) below is a moving average filter with time constant τ.

[0078] [Mathematical Expression 12]

[0079]

[0080] Filter F dref (s) can be approximated using the moving average filter of equation (12). Equation (13) below represents the second-order Pad approximation.

[0081] [Mathematical Expression 13]

[0082]

[0083] The moving average filter applying the second-order Pad approximation is shown in equation (14) below.

[0084] [Mathematical Expression 14]

[0085]

[0086] Filter F dref (s) can be obtained by combining two moving average filters. The following equation (15) represents the synthesis of the time constant τ 1d τ 2d The transfer function is obtained by using two moving average filters.

[0087] [Mathematical Expression 15]

[0088]

[0089] Steering calculation unit 104 calculates the steering distance based on the lateral position C0', attitude angle C1', curvature C2', vehicle speed V, and yaw rate γ of the correction path. ego To calculate the steering angle command δ * .

[0090] Lateral position deviation y e Yaw angle deviation r e Yaw rate deviation γ e Equations (8), (9), and (10) indicating the use of the correction path, and the vehicle speed V and yaw rate γ of vehicle 10. ego The following equations (16), (17), and (18) are used to calculate the result.

[0091] [Mathematical Expression 16]

[0092] y e =C0′···(16)

[0093] [Mathematical Expression 17]

[0094] r e =C1′···(17)

[0095] [Mathematical Expression 18]

[0096] γ e =C2′×V-γ ego ···(18)

[0097] Specifically, the steering angle command δ * The operation is performed using the following formula (19). In formula (19), Ki (i = 1, 2, 3) represents the control gain.

[0098] [Mathematical Expression 19]

[0099]

[0100] Next, driving assistance control will be illustrated with examples of actual driving scenarios. Figure 5 This is an example of a driving scenario in Implementation 1, showing the vehicle position at the instant driving assistance control begins.

[0101] First of all, Figure 5 In the case of conventional driving assistance control without path correction, a lateral position deviation y from the target path exists. e Control begins in this state. Figure 5 Under the conditions, Figure 6 This represents the results of a simulation performed in a previous scenario without path correction. Figure 6 In the case where steering angle control is performed as in equation (19), due to the presence of lateral position deviation y e Control begins in the state of [condition], therefore, control begins with a steering angle command of a magnitude equivalent to the lateral deviation compensation term corresponding to the first term of equation (19). Furthermore, in the absence of path correction, since the target path is always parallel to the road, the second and third terms of equation (19) utilize the yaw angle deviation r [value]. e Yaw rate deviation γ e A steering angle command to suppress steering is given. As a result, the actual steering angle of the vehicle cannot follow the steering angle command when driving assistance control begins, and the actual steering angle becomes flat. Consequently, the convergence of the vehicle's lateral position deviation also becomes flat.

[0102] Next, in a vehicle equipped with a driving assistance control device 100 including the path generation device 110 of Embodiment 1 and the steering amount calculation unit 104, from Figure 5 When driving assistance control begins at the vehicle position shown, a lateral position deviation occurs relative to the target path Rt when the lane center is generated as the target path Rt by the target path generation unit 101. At this time, the lateral position correction setting unit 102 sets the lateral position correction amount y. ofst The output is a step input from the initial value of the lateral deviation at the start of driving assistance control to zero (0).

[0103] Here, as an example of the operation of the target path correction unit 103, in the case where a correction path Rr is generated 2.0 [s] after the start of control, such that the correction path converges from a lateral position deviation of 1.0 [m] to a lateral position deviation of 0 [m], a two-stage moving average filter is used with this time constant τ. 1d ,τ 2dThe sum is set in a way that is 2.0[s], for example, τ. 1d =τ 2d =1.0[s].

[0104] When the lateral position correction amount y at this time ofst The filter response when input is as follows Figure 7 As shown. In Figure 7 The motion characteristics displayed in the first layer (upper section) represent the lateral position correction amount y. ofst And the target's horizontal position y flt The timeline. The motion characteristics shown in the second layer (middle section) of this diagram represent the target's lateral velocity vy. flt The timeline. The motion characteristics displayed in the third layer (lower section) represent the target's lateral acceleration ay. flt The time history. Through this action, a correction path Rr can be generated, which, starting from the lateral position of the vehicle at the start of control, converges the deviation from the target path Rt to zero (0) after 2.0[s].

[0105] In addition, in the steering amount calculation unit 104, the steering angle command is controlled by formula (19) in a manner that follows the correction path Rr, based on the correction path calculated by the filter.

[0106] Figure 8 This is an example of using the correction path in this embodiment for auxiliary control. Figure 6 In such cases, the vehicle's actual steering angle cannot follow the steering angle command, resulting in slow convergence of the lateral position deviation. Conversely, when a correction path is used, such as Figure 8 As shown, the steering angle command changes continuously from the start of control. Since the actual steering angle can also be controlled to follow it, control can be applied to bring the lateral deviation from the corrected target path Rt to converge.

[0107] As described above, in Embodiment 1, the lateral position correction setting unit outputs a step input from the first lateral position correction amount to the second lateral position correction amount as the lateral position correction amount. When the target path correction unit converges from the first lateral position correction amount to the second lateral position correction amount, it calculates the differential value of the lateral position correction amount, i.e., the lateral velocity correction value, and the differential value of the lateral velocity correction value, i.e., the lateral acceleration correction value. Based on the lateral position correction amount, the lateral velocity correction value, and the lateral acceleration correction value, it corrects the lateral position, attitude angle, and curvature of the target path.

[0108] In addition, in the lateral position correction setting unit, the first lateral position correction is the initial value of the lateral deviation when the driving assistance control starts, and the second lateral position correction is zero (0).

[0109] As explained above, in Embodiment 1, the target path is corrected based on a lateral position correction amount set independently relative to the target path calculated based on the vehicle and road information. This allows for the calculation of continuous steering angle commands that would be impossible without a prior corrected path, while maintaining control to align the corrected path with the vehicle's travel path. Therefore, the vehicle can travel in a manner that follows the corrected path.

[0110] A variation of implementation method 1.

[0111] Figure 9 This is a functional block diagram illustrating the structure of a variation of Embodiment 1, namely the path generation device 110A and the driving assistance control device 100A. In this variation, an example of applying the path generation device 110A to lane changing will be described. Figure 9 It is Figure 1 The lateral position correction setting unit 102 is changed to the lateral position correction setting unit 102A, and the target path correction unit 103 is changed to the target path correction unit 103A.

[0112] In the lateral position correction setting unit 102A, the time when the lane change begins is set to t=0, and the lateral position correction amount y is calculated as follows (20): ofst .

[0113] [Mathematical Expression 20]

[0114]

[0115] Y lane This refers to the lateral movement to the adjacent lane, i.e., the lane width. When moving to the left-adjacent lane, the left and right lateral positions of the white line of the left-adjacent lane are used, i.e., C0. LR C0 LL The calculation is performed as shown in equation (21) below. Similarly, when moving to the adjacent lane on the right, the left lateral position and right lateral position of the white line of the adjacent lane on the right are used, i.e., C0. RR C0 RL The operation is performed as shown in equation (22) below.

[0116] [Mathematical Expression 21]

[0117]

[0118] [Mathematical Expression 22]

[0119]

[0120] In the target path correction unit 103A, the lateral position correction amount y set by the lateral position correction amount setting unit 102 is used. ofst To generate a correction path. The first half of the lane change (start to lane departure) relative to the corrected path of vehicle 10 is defined by its lateral position C0' and target lateral speed vy. flt Target lateral acceleration ay flt Same as equations (5), (6), and (7) of Implementation Method 1. The target lateral position y of the correction path for the latter half of the lane change (deviating from the current lane to reaching the center of the adjacent lane). flt Perform the calculation as shown in equation (23).

[0121] [Mathematical Expression 23]

[0122] C0′=C0+y flt -Y lane ···(twenty three)

[0123] Next, based on a specific example of a real driving scenario, the lane change operation performed by the path generation device 110A and the steering amount calculation unit 104 will be explained.

[0124] Figure 10 This is an example of a driving scenario in a variation of Implementation 1, showing the vehicle position at the instant the lane change from the left lane to the right lane begins. Figure 11 This indicates the simulated action at this moment. The lateral position correction setting unit 102A outputs a step input as the lateral position correction amount yofst, from the target path Rta before lane change (which is the current lane center, zero (0)) to the target path Rtb after lane change (which is the lane center of the adjacent lane to the right). Then, the lateral position correction setting unit 102A outputs a correction path Rr for moving from the current lane center to the lane center of the adjacent lane to the right. As a result, the steering amount calculation unit 104 can calculate the steering angle command for lane change.

[0125] Here, in the first half of the lane change (start to deviate from the current lane) Fh, the vehicle 10 identifies the left white line L1 of the left lane as the left white line L and the right white line Lr of the left lane as the right white line R, and calculates the lateral position C0' of the correction path relative to the vehicle 10 using equation (8). On the other hand, in the second half of the lane change (deviate from the current lane to reach the center of the adjacent lane) Lh, the vehicle 10 identifies the left white line R1 of the right lane as the left white line L and the right white line of the right lane as the right white line R, and the lateral position C0' of the correction path relative to the vehicle 10 becomes equation (23). Figure 11The first layer (upper layer) represents the time history of the lateral position of vehicle 10 relative to each lane. The second layer (middle section) represents the time history of the lateral position of vehicle 10 relative to the identified white lines for each lane. The third layer (lower section) represents the time history of the calculated steering angle command and the actual steering angle. Figure 11 The first layer (top section) and the second layer (middle section) display Y lane This is equivalent to the lateral movement to the adjacent lane, i.e., the lane width.

[0126] As described above, in a variation of Embodiment 1, in the lateral position correction setting unit, the first lateral position correction amount is zero (0), and the second lateral position correction amount is the lateral movement amount used for lane changing to an adjacent lane.

[0127] As explained above, in a variation of Implementation 1, a steering angle command for lane changing can be calculated by correcting the target path calculated based on the vehicle and road information by moving from the current lane center to the lane center of the adjacent lane.

[0128] In the variation of Embodiment 1, an example of path generation during lane changes was described, but by using this structure, it can also be applied to path generation when deviating from the current route. For example, by setting a lateral movement amount toward the roadside in the second lateral position correction amount in the lateral position correction amount setting unit 102A, the technology of this embodiment can also be applied when retreating to the roadside or when moving toward the roadside for passengers to get on or off.

[0129] Implementation method 2.

[0130] Figure 12 This is a functional block diagram illustrating the vehicle driving generation device 210 and driving assistance control device 200 involved in Embodiment 2.

[0131] The path generation device 110 includes a target path generation unit 101, a lateral position correction setting unit 102, a target path correction unit 103, and a steering avoidance determination unit 105.

[0132] The path generation device 210 of Embodiment 2 is obtained by adding a turning avoidance determination unit 105 to the path generation device 110 of Embodiment 1.

[0133] The steering avoidance determination unit 105 takes obstacle information from the front of the camera 3 as input, determines whether to avoid the obstacle by steering, and outputs the lateral avoidance amount when the determination is successful.

[0134] The lateral position correction setting unit 102 determines the lateral position correction amount of the target path based on the input of the lateral avoidance amount, and inputs it to the target path correction unit 103 and the steering amount calculation unit 104.

[0135] The target path correction unit 103 corrects the target path calculated by the target path generation unit 101 based on the lateral position correction amount, and inputs the corrected path information into the steering amount calculation unit 104.

[0136] The steering calculation unit 104 generates a steering angle command δ based on the correction path. * And input it into the steering ECU 5.

[0137] The specific operation of the path generation device 210 according to Embodiment 2 will be explained.

[0138] The steering avoidance determination unit 105 is based on the relative longitudinal position χ of the obstacle ahead relative to the vehicle, identified by sensors such as cameras and radar. rel , relative lateral position y obj Horizontal width w obj and relative velocity v rel The input, and the vehicle width w pre-stored in the storage device 1001 ego Avoidance margin y marge The necessity of turning to avoid obstacles is determined based on both longitudinal and lateral conditions. A turning to avoid obstacles decision is successful when both conditions are met. Furthermore, when a turning to avoid obstacles decision is successful, the lateral movement amount y required for the lateral avoidance is output. avoid .

[0139] First, the conditions for determining the necessity of longitudinal steering to avoid the obstacle are explained. This is based on the collision margin time t of the vehicle relative to the obstacle. ttc During the collision margin time t ttc The time t is lower than the preset collision margin threshold. ttc With a value of 0, the vehicle's lateral position at that moment is used as the initial value, and the step amount (lateral movement) y is output. avoid The step input is used as the lateral position correction amount y ofst .

[0140] Using the relative position of the obstacle and the vehicle x rel and relative velocity v rel The collision margin time t is expressed by the following formula (24). ttc .

[0141] [Mathematical Expression 24]

[0142]

[0143] Next, the conditions for determining the necessity of lateral turning to avoid obstacles will be explained. In the lateral determination, the relative lateral position y of the obstacle is considered. obj Horizontal width w obj The input, and the vehicle width w pre-stored in the storage device 1001 ego Avoidance margin y marge The probability of collision upon reaching the obstacle is determined. The lateral determination condition is expressed by the following equation (25).

[0144] [Mathematical Expression 25]

[0145]

[0146] Calculate and output the lateral movement y required for the vehicle to avoid the obstacle when the judgment is valid. avoid Consider the lateral movement y avoid Avoidance in both the left and right directions is calculated using the following formula (26).

[0147] [Mathematical Expression 26]

[0148]

[0149] Lateral position correction setting unit 102 is based on lateral movement amount y avoid The input, in the lateral movement y avoid If the input is a non-zero value, the vehicle's current lateral position is used as the initial value, and the lateral movement y is output. avoid The step input is used as the lateral position correction amount y ofst .

[0150] Next, based on a specific example of a real driving scenario, the operation of the driving assistance control device 200 in Embodiment 2 will be explained.

[0151] Figure 13 This represents an example of a driving scenario performed by the driving assistance control device 200. Figure 13 This indicates a driving scenario where there is an obstacle Ob in front of the vehicle's path, and a collision may occur if the vehicle continues on its original path. Figure 13 This is an example of a vehicle (this vehicle) 10 traveling along the target path Rt traveling on the correction path Rr to avoid obstacle Ob.

[0152] Figure 14 express Figure 13 The simulation results of the driving scenario. Figure 14 The solid line in the first layer (upper layer) represents the collision margin time t of the obstacle. ttc The dashed line represents the threshold t for the collision margin time. ttc0. In the second layer (middle section), solid lines represent the vehicle's actual driving position, and dashed lines represent the target path. In the third layer (lower section), solid lines represent the actual steering angle, and dashed lines represent the steering angle command.

[0153] The steering avoidance determination unit 105 determines the necessity of steering avoidance based on both longitudinal and lateral conditions, but... Figure 13 In the driving scenario, the lateral condition always holds true before avoidance, so we will consider the longitudinal condition here. Figure 14 The solid line in the first layer (upper section) represents the collision margin time t of the obstacle. ttc The state that decreases over time, at the threshold t of the collision margin time shown by the dashed line. ttc When the value is below 0, the longitudinal condition for the obstacle is met, and the steering avoidance decision unit 105 outputs a lateral movement amount y equivalent to the lateral avoidance amount. avoid At this time, the lateral position correction setting unit 102 takes the current lateral position of the vehicle as the initial value and outputs the lateral movement amount y. avoid The step input is used as the lateral position correction amount y ofst The target path correction unit 103 is set to the time constant τ of a two-stage moving average filter. 1d τ 2d The sum is called the threshold t of the collision margin time. ttc Below 0. The transmission characteristic F(s) of the two-stage moving average filter defined therefrom generates only the lateral shift correction amount y from the lateral position. ofst The threshold t between the step time and the collision margin time ttc Lateral movement y required to avoid obstacles within 0 avoid The correction path is then determined. The steering angle calculation unit 104 then provides a steering angle command to make the steering angle follow the generated correction path.

[0154] As described above, in Embodiment 2, in the lateral position correction setting unit, the first lateral position correction amount is zero (0), and the second lateral position correction amount is the lateral movement amount used to avoid obstacles in front.

[0155] As described above, in Embodiment 2, when it is determined that there is a possibility of collision with an obstacle, the path generation device 210 generates a corrective path to avoid the collision, and the steering amount calculation unit 104 can perform avoidance steering.

[0156] Implementation method 3.

[0157] Figure 15 This is a functional block diagram showing the driving assistance control device 200A in Embodiment 3. The functions other than the steering amount calculation unit 104A are the same as in Embodiment 2, therefore, descriptions are omitted.

[0158] In Embodiment 3, the steering amount calculation unit 104A is composed of an FB (feedback) steering angle command control unit 106, an FF (feedforward) steering angle command control unit 107, and a steering angle command addition unit 108.

[0159] In the FB steering angle command control unit 106, the correction path is taken as input, and the FB steering angle command δ is calculated, for example, as shown in equation (19) of embodiment 1. FB * And output it.

[0160] In the FF steering angle command control unit 107, the lateral position correction amount y is... ofst As input, based on the transmission characteristics of the target path correction unit 103 and the inverse transfer function of the vehicle motion model, the FF steering angle command δ is calculated. FF * And output it.

[0161] In the steering angle command addition unit 108, the FB steering angle command δ is set. FB * and FF steering angle command δ FF * Add them together and use the result as the steering angle command δ * Input to steering ECU 5.

[0162] Next, the specific operation of the FF steering angle command control unit 107 will be explained.

[0163] As a vehicle motion model, for example, a stable turning model that uses the steering angle response during a stable circular turn, or a two-wheeled model that approximates the lateral motion and yaw rotation of the vehicle as a two-wheeled vehicle.

[0164] Considering the stable cornering model, the transfer function G(s) from the front wheel tire angle δf to the lateral position y is known to be represented by the following equations (27), (28), and (29).

[0165] [Mathematical Expression 27]

[0166] y=G(s)δ f ···(27)

[0167] [Mathematical Expression 28]

[0168]

[0169] [Mathematical Expression 29]

[0170]

[0171] In equations (28) and (29), s represents the Laplace operator. A represents the vehicle's stability coefficient. m represents the vehicle's mass. l represents the vehicle's wheelbase. lf represents the distance between the vehicle's center of gravity and the front axle. lr represents the distance between the vehicle's center of gravity and the rear axle. kf represents the vehicle's front wheel cornering power. kr represents the vehicle's rear wheel cornering power. These parameters are pre-stored in the storage device 1001.

[0172] Additionally, considering a two-wheel model, the front wheel tire angle δ is known. f The transfer function G(s) to the lateral position y is represented by the following equations (30) and (31).

[0173] [Mathematical Expression 30]

[0174]

[0175] [Mathematical Expression 31]

[0176]

[0177] In equations (30) and (31), I represents the yaw inertial moment.

[0178] To provide the steering angle in a manner that allows the vehicle to follow the correction path, the transfer characteristic F(s) of the target path correction unit 103 and the inverse transfer function G^(-1)(s) of the vehicle motion model are used to calculate the lateral position correction amount y. ofst To FF steering angle command δ FF * The transmission characteristics can be given by the following equation (32).

[0179] [Mathematical Expression 32]

[0180]

[0181] Based on the above calculations, as an example, in such cases... Figure 16 In the case where the correction path is calculated using a filter based on the transfer characteristic F(s) of the lateral position correction amount, as described in the previous section, the FF steering angle command δ used to follow this correction path is... FF * The result is obtained by performing calculations using equation (7). Figure 16 Like the next paragraph.

[0182] Here, similar to implementation method 2, Figure 17 Indicates in Figure 13 The simulation results show the driving assistance control device 200A of embodiment 3 used in a driving scenario.

[0183] and Figure 14 same, Figure 17The solid line in the first layer (upper layer) represents the collision margin time t of the obstacle. ttc The dashed line represents the threshold t for the collision margin time. ttc 0. In the second layer (middle section) of this diagram, the solid lines represent the actual driving position of the vehicle, and the dashed lines represent the target path. In the third layer (lower section) of this diagram, the solid lines represent the actual steering angle, and the dashed lines represent the steering angle command. Since the structure of the path generation device 210 in Embodiment 3 is the same as that in Embodiment 2, therefore, Figure 17 The longitudinal conditions of the obstacles in the first layer (upper section) and the corrected target path in the second layer (middle section) of the diagram. Figure 14 same.

[0184] Here, the steering amount calculation unit 104A calculates the lateral position correction amount y. ofst As input, according to equation (32), the FF steering angle command δ is calculated. FF * The corrected target path is taken as input, and the FB steering angle command δ calculated according to equation (19) is added. FB * Then used as the steering angle command δ * Output. By adding the FF steering angle command δ FF * ,and Figure 14 In comparison, Figure 17 The larger absolute value of the mid-steering angle command confirms that the tracking accuracy of the target path is improved in response to sharp turns for obstacle avoidance.

[0185] As described above, in Embodiment 3, a steering amount calculation unit is included to calculate the target steering amount for the vehicle to travel along the corrected path obtained by the path generation device.

[0186] In addition, the steering amount calculation unit includes a transfer function model of the vehicle's lateral motion from the vehicle's steering angle to the vehicle's lateral position. Using the inverse transfer function of the vehicle's lateral motion and the transfer function of the lateral position correction amount in the target path correction unit, the unit calculates the feedforward steering angle command based on the lateral position correction amount output by the lateral position correction amount setting unit, and adds it to the target steering amount.

[0187] As described above, in the example of Embodiment 3, the lateral distance required to avoid the obstacle from the current vehicle's driving position is used as input, and the FF steering angle command for following the target's driving path is calculated. This is then added to the FB steering angle command calculated based on the corrected target path, thereby improving the following ability of the target driving path.

[0188] Although this application describes various exemplary embodiments and examples, the various features, methods and functions described in one or more embodiments are not limited to the application of a particular embodiment and can be applied to the embodiment individually or in various combinations.

[0189] Therefore, it can be assumed that numerous variations not illustrated are also included within the scope of the technology disclosed in this application. For example, this includes cases where at least one constituent element is modified, added to, or omitted, and cases where at least one constituent element is extracted and combined with constituent elements of other embodiments.

[0190] Label Explanation

[0191] 100 Driving assistance control device, 110 Path generation device, 101 Target path generation unit, 102 Lateral position correction setting unit, 103 Target path correction unit, 104 Steering amount calculation unit, 105 Steering avoidance determination unit, 106FB Steering angle command control unit, 107FF Steering angle command control unit, 108 Steering angle command addition unit.

Claims

1. A path generation device, characterized in that, include: The system comprises a target path generation unit that generates the target path for the vehicle, a lateral position correction setting unit that sets a lateral correction amount relative to the target path (i.e., a lateral position correction amount), and a target path correction unit that calculates and corrects the path based on the lateral position correction amount. The lateral position correction setting unit outputs the lateral position correction value as the step input from the first lateral position correction value to the second lateral position correction value, sets one of the first lateral position correction value and the second lateral position correction value to zero, and sets the other to a value other than zero. The target path correction unit filters the lateral position correction amount and calculates the output value of the filtering process as the filtered lateral position correction amount. The target path is represented by its lateral position relative to the vehicle's target path, its attitude angle, and its path curvature. The correction path is represented by the lateral position, attitude angle, and path curvature relative to the vehicle. The current target lateral velocity is calculated by differentiating the current lateral position correction amount after filtering. The current target lateral acceleration is calculated by second-order differentiating the current lateral position correction amount after filtering. The current target lateral position correction amount after filtering is used to correct the lateral position relative to the vehicle on the current target path and the lateral position of the corrected path is calculated. The current target lateral velocity is used to correct the attitude angle relative to the vehicle on the current target path and the attitude angle of the corrected path is calculated. The current target lateral acceleration is used to correct the curvature of the current target path and the curvature of the corrected path is calculated.

2. The path generation device as described in claim 1, characterized in that, In the lateral position correction setting unit, the first lateral position correction is the initial value of the lateral deviation when the driving assistance control starts, and the second lateral position correction is zero.

3. The path generation device as described in claim 1, characterized in that, In the lateral position correction setting unit, the first lateral position correction is zero, and the second lateral position correction is the lateral movement amount used to avoid obstacles in front.

4. The path generation device as described in claim 1, characterized in that, In the lateral position correction setting unit, the first lateral position correction is zero, and the second lateral position correction is the lateral movement amount used for lane changing to the adjacent lane.

5. A driving assistance control device, characterized in that, The device includes a path generation apparatus as described in any one of claims 1 to 4 and a steering calculation unit, the steering calculation unit calculating the target steering amount by which the vehicle travels along the corrected path determined by the path generation apparatus.

6. The driving assistance control device as described in claim 5, characterized in that, The steering amount calculation unit includes a transfer function model of the vehicle's lateral motion from the vehicle's steering angle to the vehicle's lateral position. Using the inverse transfer function of the vehicle's lateral motion and the transfer function for calculating the lateral position correction amount in the target path correction unit, the unit calculates a feedforward steering angle command based on the output of the lateral position correction amount setting unit, i.e., the lateral position correction amount, and adds it to the target steering amount.

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