Vehicle control device

Abstract

To provide a vehicle control device for properly reducing a target vehicle speed for urging a return to a target locus of a vehicle when the vehicle deviates from the target locus, and quickly returning the target vehicle speed to an original state when re-deviation possibility is low, thereby securing safety without imparting a discomfort to a boarding person.SOLUTION: A vehicle control device is provided which performs control for traveling a vehicle along a target locus at a target vehicle speed, the vehicle control device determines whether or not a vehicle 501 is in a deviated state deviated from the target locus 502, and calculates a restraining quantity for reducing the target vehicle speed based on a deviated quantity showing the deviated state when determined that the vehicle is in the deviated state, and holds the maximum value of the restraining quantity and reduces the held value of the restraining quantity at a predetermined speed when the vehicle restores to the target locus from the deviated state and satisfies a preset release condition.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In general, in autonomous driving, the target vehicle speed is a value arbitrarily set by the driver or a legal speed limit, and it is assumed that the vehicle will travel on a paved road at the set target vehicle speed. Furthermore, in order to improve driving stability during cornering, there are methods such as limiting the vehicle speed V based on the road friction force μ and curvature r (formula (1) in Figure 9) and limiting the vehicle speed V based on a preset maximum lateral acceleration Yg_t (formula (2) in Figure 10). By generating the target vehicle speed using the above methods, tracking to the target trajectory during driving in general urban areas is ensured.

[0003] However, even with the above method, deviation from the target trajectory may occur due to the influence of disturbances that are difficult to predict. As a method for preventing and suppressing deviation in such cases, for example, the following Patent Documents 1 and 2 disclose techniques.

[0004] Patent Document 1 discloses a technology for suppressing vehicle acceleration and preventing the vehicle from departing from a lane when it is predicted that the vehicle will deviate from the lane during autonomous driving or when it is determined that the vehicle has deviated from the lane. Patent Document 2 discloses a technology for preventing the vehicle from accelerating again by changing the target vehicle speed to the vehicle speed after lane departure prevention control when the vehicle speed after the departure prevention device mounted on the vehicle during autonomous driving is activated is lower than a preset target vehicle speed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-327011 A [Patent Document 2] JP 2007-8332 A Summary of the Invention [Problem to be solved by the invention]

[0006] External disturbances that cause the vehicle to deviate from the target trajectory while driving around a curve mainly occur when road friction is lower than expected by the autonomous driving system. When the vehicle deviates from the target trajectory due to the influence of external disturbances, attempts to prevent or suppress the deviation by applying the inventions described in Patent Documents 1 and 2 each have the following problems.

[0007] In Patent Document 1, the vehicle speed is suppressed and acceleration is limited when departure prevention control is activated, but if the control is subsequently stopped, the vehicle may accelerate again and depart again, or acceleration and deceleration may be repeated due to departure prevention control.

[0008] On the other hand, in Patent Document 2, it is not necessarily possible to return to the target lane at the vehicle speed after control activation, and no consideration is given to a method for restoring the target vehicle speed. Therefore, if the target is continually set low, there is a risk that passengers will feel uncomfortable.

[0009] In view of the above, an object of the present invention is to provide a vehicle control device that appropriately reduces the target vehicle speed to encourage the vehicle to return to the target trajectory when the vehicle deviates from the target trajectory, and quickly returns the target vehicle speed to its original state if the possibility of re-deviation is low, thereby ensuring safety without causing discomfort to passengers. [Means for solving the problem]

[0010] A vehicle control device of the present invention that solves the above problems is a vehicle control device that performs control to make a vehicle travel along a target trajectory at a target vehicle speed, determining whether the vehicle is in a deviation state from the target trajectory; When it is determined that the deviation state exists, a suppression amount for reducing the target vehicle speed is calculated based on a deviation amount indicating the deviation state; A maximum value of the suppression amount is held, and the target vehicle speed is suppressed using the held value. When the vehicle returns to the target trajectory from the deviation state and a preset release condition is satisfied, the held value of the suppression amount is decreased at a predetermined speed. Effect of the Invention

[0011] According to the present invention, when the vehicle deviates from the target trajectory, the vehicle speed is appropriately suppressed, and when suppression is not necessary, the vehicle speed is gradually restored, thereby enabling safe driving. Further features related to the present invention will become apparent from the description of this specification and the attached drawings. In addition, problems, configurations, and effects other than those described above will become apparent from the following description of the embodiment. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a system according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a diagram illustrating the configuration of a target vehicle speed suppression amount calculation unit. [Diagram 3] 5 is a flowchart showing the process of a control necessity determination unit. [Figure 4] 11 is a flowchart showing conditions for a suppression amount gradually decreasing process. [Diagram 5] FIG. 13 is a diagram showing an example in which a vehicle deviates from a target trajectory. [Figure 6] 4 is a time chart showing an example of operation in the present embodiment. [Figure 7] 6 is a time chart showing another operation example in the present embodiment. [Figure 8] 10 is a time chart showing yet another operation example in the present embodiment. [Figure 9] A diagram showing equation (1). [Figure 10] A diagram showing equation (2). [Figure 11] A diagram showing equation (3). [Figure 12] A diagram showing equation (4). [Figure 13] A diagram showing equation (5). [Figure 14] A diagram showing equation (6). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a vehicle control device according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a vehicle control system according to this embodiment.

[0014] The vehicle system is a system for autonomously or automatically driving a vehicle along a target trajectory at a target vehicle speed, and for managing the target vehicle speed when the vehicle deviates from the target trajectory. The vehicle system includes various information acquisition units 12 for acquiring information on the surrounding environment and the vehicle state, an ECU 11 mounted on the vehicle, and various actuators 13 for controlling the vehicle based on control signals output from the ECU 11.

[0015] The information acquisition unit 12 has a vehicle information acquisition unit 101 such as a wheel speed sensor, an acceleration sensor, a yaw rate sensor, etc., a vehicle position acquisition unit 102 such as GPS, HD-MAP, etc., and a route information acquisition unit 103 such as NAVI, C2X, etc.

[0016] The vehicle information acquisition unit 101 acquires information on the vehicle motion such as yaw rate and acceleration, information on the execution or non-execution of behavior control such as ABS and ESC, and the like, and outputs this information to the ECU 11 .

[0017] The vehicle position acquisition unit 102 acquires vehicle position information in an absolute coordinate system such as the World Geodetic System, and outputs the information to the vehicle position estimation unit 104 and the route calculation unit 105. If the vehicle position information cannot be acquired from the outside, the unit behaves in such a way that it can be determined that the vehicle position cannot be acquired, such as by holding the previous value or outputting a specific value, or by outputting a signal indicating whether the vehicle position can be acquired.

[0018] The route information acquisition unit 103 uses NAVI or C2X to acquire the vehicle's destination, the route to the destination, and traffic information and surrounding information associated therewith, and outputs the information to the route calculation unit 105 and the target vehicle speed calculation unit 108.

[0019] The ECU 11 constitutes a vehicle control device, and includes, as internal functions, a vehicle position estimation unit 104, a route calculation unit 105, a target trajectory calculation unit 106, a deviation amount calculation unit 107, a target vehicle speed calculation unit 108, a target vehicle speed suppression amount calculation unit 109, a target vehicle speed subtraction unit 110, and an operation amount calculation unit 111. Each of these components is a specific representation of a part of a software program executed by a microcomputer built into the ECU 11 using functional blocks. The ECU 11 includes hardware such as a CPU and a memory, and a software program executed by the hardware, and realizes each of these functions through cooperation between the hardware and the software program.

[0020] The vehicle position estimation unit 104 uses the output of the vehicle information acquisition unit 101 and the output of the vehicle position acquisition unit 102 to estimate the vehicle position with higher accuracy than the vehicle position acquisition unit 102. The route calculation unit 105 uses the output of the vehicle position acquisition unit 102 and the output of the route information acquisition unit 103 to calculate a travel route to the destination.

[0021] The target trajectory calculation unit 106 calculates a target trajectory based on the output of the vehicle position estimation unit 104 and the output of the route calculation unit 105. The target trajectory calculation unit 106 calculates detailed and continuous position information about a direction to travel in the vicinity of the vehicle as a target trajectory.

[0022] The deviation amount calculation unit 107 judges whether the vehicle is in a deviation state from the target trajectory based on the output of the vehicle position estimation unit 104 and the output of the target trajectory calculation unit 106, and calculates a deviation amount indicating the deviation state when it is judged that the vehicle is in a deviation state. The deviation amount can be, for example, a distance between the vehicle center and the target trajectory, such as a distance from the target trajectory in the road width direction, or a deviation speed of the vehicle from the target trajectory calculated by differentiating the distance with respect to time.

[0023] The target vehicle speed calculation unit 108 calculates the target vehicle speed based on map information such as the laws and regulations of the road on which the vehicle is traveling, arbitrary limit values, the shape of the target trajectory, etc. The target vehicle speed calculation unit 108 can acquire map information from, for example, a map database of an in-vehicle navigation device or from an external server through road-to-vehicle communication.

[0024] The target vehicle speed suppression amount calculation unit 109 calculates a suppression amount for suppressing the target vehicle speed when the vehicle deviates from the target trajectory based on the target trajectory, the target vehicle speed, and the deviation amount. The suppression amount can be at least one of the speed amount or the ratio by which the target vehicle speed of the vehicle is reduced.

[0025] When the suppression amount is calculated by the target vehicle speed suppression amount calculation unit 109, the target vehicle speed subtraction unit 110 calculates the target vehicle speed at the time of departure using the target vehicle speed before the departure and the suppression amount. When the suppression amount is a speed, the target vehicle speed subtraction unit 110 subtracts the suppression amount from the target vehicle speed before the departure to calculate the target vehicle speed at the time of departure, and when the suppression amount is not a speed amount but a rate at which the target vehicle speed is reduced, the target vehicle speed subtraction unit 110 multiplies the rate by the target vehicle speed before the departure to calculate the target vehicle speed at the time of departure.

[0026] When the vehicle does not deviate from the target trajectory, that is, when the suppression amount is not calculated by the target vehicle speed suppression amount calculation unit 109, the target vehicle speed subtraction unit 110 outputs the target vehicle speed calculated by the target vehicle speed calculation unit 108 as it is to the operation amount calculation unit 111. The operation amount calculation unit 111 calculates the operation amount of each actuator 13, such as the steering control unit 112, the braking control unit 113, and the drive control unit 114, according to the target vehicle speed calculated by the target vehicle speed subtraction unit 110.

[0027] FIG. 2 is a diagram for explaining the configuration of the target vehicle speed suppression amount calculation unit 109. As shown in FIG. The target vehicle speed suppression amount calculation unit 109 has a reference vehicle speed calculation unit 201 , a control necessity determination unit 202 , a suppression amount calculation unit 203 , a suppression amount holding unit 204 , a suppression amount conversion unit 205 , and a gradual decrease amount calculation unit 206 .

[0028] The reference vehicle speed calculation unit 201 calculates the reference vehicle speed VSP from the actual vehicle speed, curvature, and deviation amount of the vehicle.R Calculate the standard vehicle speed VSP R is the maximum vehicle speed at which the vehicle can pass the target trajectory without deviating from the target trajectory. In this embodiment, the reference vehicle speed VSP R As one of the methods for calculating this, the formula (3) shown in FIG. 11 is used. In equation (3), VSP R :Reference vehicle speed, VSP cur : Actual vehicle speed, r cur : turning radius while driving, r tgt : This is the turning radius of the target trajectory. At this time, the turning radius while driving is r cur is the turning radius of the target trajectory r tgt and the deviation amount eY are used to calculate the deviation amount using equation (4) shown in FIG.

[0029] In addition, the turning radius of the target trajectory r tgt and the deviation amount eY may be set to prevent a malfunction that results in suppression control of the target vehicle speed being performed while the vehicle is traveling in a straight line. Also, a dead zone may be set for the deviation amount eY to prevent the vehicle from operating too sensitively due to vehicle control, thereby preventing the ride comfort of the passengers from becoming worse.

[0030] In addition, when the vehicle deviates from the target trajectory to the inside of the turning circle, the turning radius r tgt The turning radius while driving is r cur becomes larger than (r tgt >r cur ), standard vehicle speed VSP R The actual vehicle speed VSP cur (VSP R >VSP cur ), there is a possibility that the target vehicle speed will be controlled to increase. R The actual vehicle speed VSP cur (VSP R <VSP cur ) or, if the vehicle deviates from the target trajectory to the inside of the turn, it may be determined that the deviation amount eY has not occurred.

[0031] The suppression amount calculation unit 203 calculates the reference vehicle speed VSP R and target vehicle speed VSP tgt The suppression amount S is calculated from the reference vehicle speed VSP as shown in equation (5) of FIG. R Target vehicle speed VSP tgt The suppression amount S can be calculated by subtracting the ratio obtained by dividing by from 1. Alternatively, instead of the suppression amount S, a suppression amount calculated using a certain standard according to the departure speed may be used. In this case, the suppression amount increases as the departure speed increases. Also, the suppression amount may be calculated based on both the departure amount and the departure speed, and the larger value may be used.

[0032] The control necessity determination unit 202 determines whether or not this control is necessary, that is, whether or not control to suppress the target vehicle speed is necessary, based on the target vehicle speed, the curvature, and the amount of deviation from the target trajectory of the vehicle. The curvature c in this embodiment is the curvature of the vehicle trajectory during turning, and can be easily converted to an arbitrary turning radius r by the formula (6) in FIG.

[0033] When the control necessity determination unit 202 determines that control is necessary, the suppression amount retention unit 204 compares the suppression amount S with the suppression amount retention value Sh and retains the larger value (maximum value), and when control is not necessary, gradually decreases the retention value Sh to 0.

[0034] The gradual decrease amount calculation unit 206 calculates the amount of gradual decrease by which the held value Sh is gradually decreased based on the held value Sh, the target vehicle speed, and the determination of whether or not control is required. For example, when the suppression amount S is held as a ratio, when it is desired to restore the target vehicle speed suppressed at an arbitrary acceleration, it is necessary to calculate the amount of gradual decrease according to the arbitrary acceleration and the target vehicle speed, and therefore the gradual decrease amount calculation unit 206 is provided.

[0035] The suppression amount conversion unit 205 converts the held value into a vehicle speed dimension based on the held value and the target vehicle speed. The held value converted into the vehicle speed dimension by the suppression amount conversion unit 205 is output from the target vehicle speed suppression amount calculation unit 109 to the target vehicle speed subtraction unit 110.

[0036] FIG. 3 is a flowchart showing the process of the control necessity determination unit of FIG. The control necessity determining unit 202 executes a determination process shown in the flowchart of FIG. 3, for example, at a preset program cycle having a predetermined period.

[0037] First, the turning radius r of the target trajectory on the currently traveling road is tgt It is determined whether the turning radius r is less than an arbitrary threshold value N (S301). tgt If is less than the threshold value N (YES), it is determined that the vehicle is turning, and then it is determined whether the departure amount eY is greater than an arbitrary departure determination threshold value M (S302).

[0038] If the departure amount eY is greater than the departure judgment threshold value M (YES), the suppression amount is retained (S303). Here, a process of retaining the maximum value of the suppression amount is performed. Specifically, the suppression amount calculated based on the departure amount eY is compared with the retained suppression amount value, and the larger value is retained as the retained value Sh. On the other hand, when either the condition of S301 or S302 is not satisfied, for example, when the vehicle is not turning or when the departure amount eY is equal to or less than the threshold value M, a suppression amount gradual reduction process is performed to gradually reduce the retained value Sh (S304).

[0039] In this embodiment, the necessity of suppression control is judged based on the separation distance as the departure amount, but the departure speed may be used as the departure amount, or both the separation distance and the departure speed may be used, and suppression control may be performed if either of them exceeds a standard. The departure speed can be calculated, for example, by differentiating the separation distance with respect to time.

[0040] Next, the process of S304 will be described in detail. Fig. 4 is a flow chart showing the contents of the suppression amount gradual reduction process shown in S304 of Fig. 3. The gradual reduction process is a part that selects a gradual reduction speed according to the situation, and is as follows in this embodiment. S401 to S404 become the release conditions for gradually reducing the suppression amount and releasing the suppression control of the target vehicle speed.

[0041] If the curvature of the target trajectory is equal to or less than a certain value (YES in S401) or the curvature is decreasing (YES in S402), the vehicle is not turning or is exiting a turn, and the possibility of the vehicle deviating from the target trajectory or deviating again is low. Therefore, it is determined that suppression of the target vehicle speed is unnecessary, and a process of gradually decreasing the retained value Sh is performed (S405). In other words, if the curvature of the target trajectory is equal to or less than a certain value, or the curvature of the target trajectory is gradually decreasing as the curvature of the target trajectory moves in the traveling direction of the vehicle, a gradual decrease process is performed to decrease the retained value Sh of the suppression amount at a first speed. The gradual decrease of the retained value Sh is performed using the gradual decrease amount calculated in the gradual decrease amount calculation unit 206, and the retained value Sh is decreased at a predetermined first speed.

[0042] On the other hand, if the curvature during turning of the vehicle is constant (YES in S403) or the target vehicle speed is decreasing (YES in S404), the possibility of the vehicle deviating or deviating again from the target trajectory is low, although not as low as in the conditions of S401 and S402, so a process is performed to gradually decrease the held value Sh at a second speed that is gentler than S405 (S406). In other words, when the curvature during turning of the vehicle is constant or the target vehicle speed has decreased by a predetermined value or more due to suppression of the target vehicle speed, a process is performed to decrease the held value of the suppression amount at a second speed that is slower than the first speed.

[0043] As a result, the vehicle is accelerated more slowly compared to S405, and the process of gradually decreasing the held value Sh is performed while observing the state of the deviation amount and ensuring safety, thereby reducing discomfort felt by the passengers. The first speed of S405 and the second speed of S406 are set so that the second speed of S406 gradually decreases the held value at a slower speed than the first speed of S405, and the second speed of S406 decreases the held value Sh at a slower speed.

[0044] Furthermore, if the condition of S302 is no longer satisfied but the conditions of S401 to S404 are not satisfied (NO in S404), it is determined that there is a possibility of re-departure, and re-departure is suppressed by continuing to hold the suppression amount (S407). In other words, if the curvature of the target trajectory is greater than a certain value (NO in S401), and the curvature of the target trajectory has not decreased (NO in S402), and the curvature during turning of the vehicle has increased (NO in S403), and the target vehicle speed has not decreased by a predetermined value or more due to suppression of the target vehicle speed (NO in S404), a process of continuing suppression of the target vehicle speed using the held value Sh (S407) is performed.

[0045] FIG. 5 is a diagram showing an example in which the vehicle deviates from the target trajectory, and FIG. 6 is a time chart showing an example of operation in this embodiment.

[0046] 5 and 6 show, as a basic operation of this embodiment, a case in which a vehicle 501 given a constant target vehicle speed is displaced to the outside of the turn due to an external disturbance while turning, deviating from a target trajectory 502, and then returning to the target trajectory 502 through suppression control of the target vehicle speed.

[0047] The vehicle control system causes the vehicle 501 to travel along the target trajectory 502 at the target vehicle speed. When the condition that the turning radius of the target trajectory is smaller than the turning determination threshold N is satisfied (YES in S301), the vehicle 501 deviates from the target trajectory 502 due to a disturbance, and the traveling position starts to change to the outside of the turn, as shown at t1 and t2 in Fig. 5. When the deviation amount eY exceeds the deviation determination threshold M of the dead zone set as a tolerance, the control necessity determination unit 202 determines that control is necessary, the determination in S302 shown in the flowchart in Fig. 3 becomes YES, and the process of holding the suppression amount is started in S303.

[0048] Then, the suppression amount holding unit 204 holds the value (suppression amount S) calculated using equation (5) in Fig. 13 based on the standard vehicle speed calculated using equation (3) in Fig. 11 and equation (4) in Fig. 12 as a held value Sh. That is, the standard vehicle speed is calculated by the standard vehicle speed calculation unit 201, the suppression amount calculation unit 203 calculates the suppression amount S using the standard vehicle speed and the target vehicle speed, and the suppression amount holding unit 204 holds the suppression amount S as a held value Sh.

[0049] 5 and 6, when the vehicle 501 is affected by a disturbance and the deviation amount eY increases further, the suppression amount S also increases according to the deviation amount eY, and the hold value Sh of the suppression amount S also increases according to the increase in the suppression amount S. Then, the target vehicle speed VSP tgt has the suppression amount S subtracted from it, decreasing it from the pre-suppression value V to the suppressed value V'.

[0050] 5, the vehicle 501 performs control to return to the target trajectory 502, but because the deviation amount eY from the target trajectory is greater than the deviation judgment threshold M, the determination in S302 shown in the flowchart in Fig. 3 remains YES, and processing is performed in S303 to hold the suppression amount at the hold value Sh. In other words, in a state in which the deviation amount eY is greater than the deviation judgment threshold M, the determination in S302 is not NO, and the process does not proceed to the suppression amount gradual decrease processing in S304.

[0051] 6B, the suppression amount S calculated by the suppression amount calculation unit 203 decreases according to the deviation amount eY, but the hold value Sh is held at the value (maximum value) of the suppression amount S at t3 by the suppression amount holding unit 204. tgt is also held at a suppressed value V'.

[0052] 5, the departure amount eY of the vehicle 501 falls within the departure judgment threshold M, so the determination in S302 is NO. However, if none of the conditions in S401 to S404 shown in FIG. 4 are satisfied at this point, the process proceeds to S407, where the same control as in the previous cycle is executed. Therefore, as shown between t4 and t5 in FIG. 6, the hold value Sh continues to be held at the maximum value of the suppression amount S, and the target vehicle speed VSP tgt continues to be held at the suppressed value V'.

[0053] Then, finally, as shown at t5 in FIG. 5, if the determination in any of S401 to S404 shown in FIG. 4 is YES, it is determined that the possibility of the vehicle 501 re-departing is low, and the hold value Sh is gradually decreased, and the target vehicle speed is gradually restored to the target vehicle speed before the suppression.

[0054] In this way, when deviation from the target trajectory 502 occurs, the target vehicle speed VSP tgt Since the target vehicle speed VSP is suppressed and reduced, the actual vehicle speed and acceleration of the vehicle 501 are suppressed, and the vehicle 501 can quickly return to the target path 502. tgt Since the suppression amount of the target vehicle speed VSP is held at the maximum value Sh, tgt By appropriately suppressing the deviation, the vehicle 501 can be quickly returned to the target trajectory 502. Even if the vehicle 501 returns to the target trajectory 502, if the predetermined release conditions S401 to S404 are not satisfied, the suppression amount continues to be held at the held value Sh, which is the maximum value, so that it is possible to prevent the vehicle 501 from deviating again after returning to the target trajectory 502.

[0055] FIG. 7 is a time chart showing another operation example in this embodiment. This time chart assumes a situation where a vehicle given a constant target vehicle speed deviates from the target trajectory during turning, then temporarily returns to the target trajectory, but then deviates again due to the influence of further disturbances. When the vehicle deviates from the target trajectory due to a disturbance, as shown from t1 to t2 in FIG. 7, the suppression amount calculated by the suppression amount calculation unit 203 increases to S1, and the target vehicle speed is suppressed from V1 to V1'. Then, the suppression amount is held at S1 from t2 by the suppression amount holding unit 204, and at t3, the deviation amount eY falls within the deviation determination threshold M, and the vehicle returns to the target trajectory. Next, at t4, when any of the release conditions of S401 to S404 in FIG. 4 is satisfied, the held value Sh is gradually decreased from S1, and the target vehicle speed is gradually restored.

[0056] So far, the flow from deviation to return is the same as in FIG. 6. However, in FIG. 7, at t5, during the gradual decrease of the held value Sh, it is assumed that the deviation amount eY turns to increase again and the vehicle deviates from the target trajectory again. At this time, the suppression amount S is S2 and the vehicle speed V is V2'.

[0057] When the deviation amount eY of the vehicle at t5 becomes larger than the deviation determination threshold M, the determination in S302 in FIG. 3 becomes YES, so the suppression amount gradual decrease process by S304 stops immediately. Then, as shown in FIG. 7, the held value Sh during the gradual decrease stops decreasing and is held at S2, and the vehicle has the target vehicle speed held at V2'.

[0058] After that, as the deviation amount eY of the vehicle increases, the suppression amount S calculated by the suppression amount calculation unit 203 increases. When it becomes larger than S2 at t6 (S2 < S), from t6 to t7, the held value Sh is updated to gradually increase again, and the target vehicle speed decreases again from V2'. Then, at t7, since the deviation amount eY reaches the maximum, S3 of the suppression amount S is held as the held value Sh.

[0059] As described above, if the vehicle deviates again while the retained value Sh is decreasing, the decrease is immediately stopped and the retention of the suppression amount is resumed. If the deviation amount eY increases further and the calculated suppression amount exceeds the value previously retained, a larger suppression amount is retained, thereby reducing the time required to suppress the vehicle from deviating again and to return to normal.

[0060] FIG. 8 is a time chart showing yet another operation example in this embodiment. This time chart assumes a case in which a vehicle given a constant target vehicle speed, as shown in Figure 6, deviates from the target trajectory while turning, and then temporarily returns to the target trajectory, but the target vehicle speed changes before the gradual decrease in the held value begins.

[0061] From t1 to t2, the vehicle deviates from the target trajectory, the calculated suppression amount S increases to S1, the target vehicle speed is suppressed from V1 to V1', and at t3, the vehicle deviation amount eY falls within the deviation judgment threshold M, and the vehicle returns to the target trajectory.

[0062] However, between t4 and t5, the target vehicle speed V decreases from V1 to V2, and the target vehicle speed V' after the suppression also decreases from V'1 to V'2. Furthermore, between t6 and t7, the target vehicle speed V increases from V2 to V1, and the target vehicle speed V' after the suppression also increases from V'2 to V'1.

[0063] At this time, V1=40km / h, V2=10km / h. If S1 of the suppression amount S is not a percentage but S1=10km / h, the target vehicle speed V' after suppression will drop from V'1=30km / h to V'2=0km / h between t4 and t5, and the vehicle will stop. Therefore, when the suppression amount is held in the vehicle speed dimension, in order to avoid stopping or extremely slowing down when the target vehicle speed drops as described above, control is required to deal with the situation, such as subtracting the held value according to the target vehicle speed. On the other hand, when the suppression amount is held in percentage, when V1=40km / h, V'1=30km / h, S1=0.25. Therefore, even if V2=10km / h at t5, V'2=7.5km / h and the vehicle will not stop. As described above, by calculating and holding the suppression amount as a percentage, even if the target vehicle speed changes, complex calculations are not required, and smooth driving is possible.

[0064] 6 to 8, after the vehicle deviates and the target vehicle speed is suppressed, a handover process may be performed to terminate the automatic driving and switch the main driving role to manual driving by the passenger at any timing. When performing a handover, the vehicle control system holds the suppression amount, continues to suppress the target vehicle speed, notifies the passenger that the automatic driving is ending, and when the passenger is ready to start driving, immediately switches to manual driving and transfers the main driving role to the passenger.

[0065] The vehicle control system of the present embodiment described above determines whether the vehicle 501 is in a deviation state where it has deviated from the target trajectory 502, and if it is determined that the vehicle 501 is in a deviation state, calculates a suppression amount for lowering the target vehicle speed based on the deviation amount indicating the deviation state.The system then holds the maximum suppression amount, suppresses the target vehicle speed using the held value, and reduces the held value of the suppression amount at a predetermined speed when the vehicle returns to the target trajectory from the deviation state and satisfies a preset release condition.

[0066] According to the vehicle control system of this embodiment, when the vehicle deviates from the target trajectory, a suppression amount for lowering the target vehicle speed is calculated based on the deviation amount. The target vehicle speed is then lowered using the suppression amount, and the acceleration and vehicle speed of the vehicle are suppressed. In addition, by storing the suppression amount as a ratio to the target vehicle speed, even if the target vehicle speed changes, it is possible to respond without requiring complex calculations, and it is possible to prevent the target vehicle speed from becoming 0.

[0067] However, if the suppression is continued as it is, the vehicle speed will continue to decrease even when the possibility of departure is low and suppression is unnecessary, which will cause discomfort to the passengers. Therefore, a condition must be set and the suppression control must be stopped, but at that time, the suppression amount is not set to 0 by turning the suppression control ON / OFF and the suppression amount is gradually decreased to gradually recover the vehicle speed. Also, as shown in S401 to S404 in FIG. 4, a plurality of conditions for starting the gradual decrease of the suppression amount are set, and the speed of the gradual decrease is changed according to each condition, and the vehicle speed is safely recovered by switching between the first speed in S405 and the second speed in S406.

[0068] According to the vehicle control system of this embodiment, when the vehicle 501 deviates from the target trajectory 502, the target vehicle speed is appropriately reduced to encourage the vehicle 501 to return to the target trajectory 502, and the target vehicle speed can be appropriately continued to be suppressed after the vehicle returns to the target trajectory so as to prevent the vehicle from deviating again. Then, when the possibility of the vehicle deviating again is low, the target vehicle speed is quickly returned to its original state, and excessive acceleration / deceleration and stopping of the vehicle when the target vehicle speed changes can be prevented, and safety can be ensured without giving a sense of discomfort to the passengers.

[0069] Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the spirit of the present invention described in the claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0070] 11 ECU (vehicle control device), 12 information acquisition unit, 13 actuator, 109 target vehicle speed suppression amount calculation unit, 110 target vehicle speed subtraction unit, 201 standard vehicle speed calculation unit, 202 control necessity determination unit, 203 suppression amount calculation unit, 204 suppression amount holding unit, 205 suppression amount conversion unit, 206 gradual reduction amount calculation unit

Claims

1. A vehicle control device that performs control to run a vehicle along a target trajectory at a target vehicle speed, determining whether the vehicle is in a deviation state from the target trajectory; When it is determined that the deviation state exists, a suppression amount for reducing the target vehicle speed is calculated based on a deviation amount indicating the deviation state; A maximum value of the suppression amount is held, and the target vehicle speed is suppressed using the held value. a vehicle control device which reduces a held value of the suppression amount at a predetermined speed when the vehicle returns to the target trajectory from the deviation state and a preset release condition is satisfied.

2. 2. The vehicle control device according to claim 1, wherein the deviation amount is a distance between the vehicle and the target trajectory, or a deviation speed at which the vehicle deviates from the target trajectory.

3. 2. The vehicle control device according to claim 1, wherein the suppression amount is at least one of an amount by which a target vehicle speed of the vehicle is reduced, or a rate at which the target vehicle speed is reduced.

4. The vehicle control device according to claim 1, characterized in that if it is determined that the vehicle is again in the departure state while the held value of the suppression amount is being decreased at a predetermined speed, the gradual decrease of the held value of the suppression amount is stopped, the maximum value of the suppression amount is maintained, and the target vehicle speed is suppressed using the held value.

5. When the curvature of the target trajectory is equal to or smaller than a certain value, or when the curvature of the target trajectory is gradually decreasing as the curvature of the target trajectory moves in the traveling direction of the vehicle, the hold value of the suppression amount is decreased at a first speed; The vehicle control device according to claim 1, characterized in that when the curvature of the target trajectory is greater than a constant value and does not gradually decrease as the curvature of the target trajectory shifts in the direction of travel of the vehicle, and when the curvature during turning of the vehicle is constant or the target vehicle speed has decreased by more than a predetermined value due to the suppression of the target vehicle speed, the retained value of the suppression amount is decreased at a second speed slower than the first speed.

6. The vehicle control device according to claim 5, further comprising: continuing to suppress the target vehicle speed using the held value when the curvature of the target trajectory is greater than a certain value, the curvature of the target trajectory is not decreasing, the curvature of the target trajectory is increasing while the vehicle is turning, and the target vehicle speed has not decreased by more than a predetermined value due to the suppression of the target vehicle speed.

7. The vehicle control device according to claim 1, characterized in that after suppressing the target vehicle speed using the held value due to deviation of the vehicle from the target trajectory, a handover process is performed to switch driving of the vehicle from automatic driving to manual driving.

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