Connected vehicle control device, connected vehicle control method, and connected vehicle control program

Abstract

The control device is used for a connected vehicle provided with a towing vehicle and a trailer towed by the towing vehicle. The control device is configured to execute a state quantity acquisition process, a predicted orbit information calculation process, and a display process. The state quantity acquisition process is a process for acquiring a state quantity of the connected vehicle. The predicted orbit information calculation process is a process for calculating predicted orbit information of the trailer on the basis of the state quantity. The display process is a process of displaying the predicted track information by operating the display device.

Description

Technical Field

[0001] The present disclosure relates to a control device for a connected vehicle, a control method for a connected vehicle, and a control program for a connected vehicle. Background Art

[0002] For example, Patent Document 1 listed below describes a control device that displays the time until the traction angle returns to zero in a coupled vehicle.

[0003] Patent Document 1: U.S. Patent No. 10112646

[0004] In the above control device, it is difficult for the driver to sequentially grasp the behavior of the trailer. Summary of the invention

[0005] In one aspect of the present disclosure, a control device for a coupled vehicle including a tractor and a trailer towed by the tractor is provided. The control device is configured to execute a state quantity acquisition process, a predicted trajectory information calculation process, and a display process. The state quantity acquisition process is a process for acquiring a state quantity of the coupled vehicle. The predicted trajectory information calculation process is a process for calculating predicted trajectory information of the trailer based on the state quantity. The display process is a process for displaying the predicted trajectory information by operating a display device.

[0006] In another aspect of the present disclosure, a control method for a coupled vehicle including a tractor and a trailer towed by the tractor is provided. The control method comprises the steps of executing a state quantity acquisition process, a predicted trajectory information calculation process, and a display process. The state quantity acquisition process is a process of acquiring a state quantity of the coupled vehicle. The predicted trajectory information calculation process is a process of calculating predicted trajectory information of the trailer based on the state quantity. The display process is a process of displaying the predicted trajectory information by operating a display device.

[0007] In another aspect of the present disclosure, a control program for a coupled vehicle including a tractor and a trailer towed by the tractor is provided. The control program is a program for causing a computer to execute a state quantity acquisition process, a predicted trajectory information calculation process, and a display process. The state quantity acquisition process is a process for acquiring the state quantity of the coupled vehicle. The predicted trajectory information calculation process is a process for calculating the predicted trajectory information of the trailer based on the state quantity. The display process is a process for displaying the predicted trajectory information by operating a display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a perspective view showing a structure of a connected vehicle according to an embodiment.

[0009] Figure 2It is a block diagram showing the structure of the control system involved in this embodiment.

[0010] Figure 3 It is a diagram illustrating the reverse control of the coupled vehicles according to the present embodiment.

[0011] Figure 4 It is a diagram showing a model of a connected vehicle according to this embodiment.

[0012] Figure 5 This is a flowchart showing the procedure of processing executed by the control device according to this embodiment.

[0013] Figure 6 This is a flowchart showing the procedure of processing executed by the control device according to this embodiment.

[0014] Fig. 7A and Figure 7B This is a diagram showing a method of displaying a predicted trajectory.

[0015] Fig. 8A and Figure 8B It is a diagram showing a display example involved in this embodiment.

[0016] Fig. 9A and Fig. 9B It is a diagram showing a display example involved in this embodiment.

[0017] Fig. 10A and Fig. 10B It is a diagram showing a display example involved in this embodiment.

[0018] Fig.11A and Fig. 11B 2 is a timing chart illustrating control of the virtual steering angle according to the present embodiment.

[0019] Fig. 12A and Fig. 12B It is a diagram showing a display example according to a modification of the above-mentioned embodiment.

[0020] Fig.13A and Fig. 13B It is a diagram showing a display example according to a modification of the above-mentioned embodiment.

[0021] Fig.14A and Fig. 14B It is a diagram showing a display example according to a modification of the above-mentioned embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, one embodiment will be described with reference to the drawings.

[0023] "Structure connecting vehicles"

[0024] like Figure 1 As shown, the coupled vehicle 10 includes a tractor 20 and a trailer 30. The tractor 20 includes front wheels 22 and rear wheels 24. The front wheels 22 include two wheels, a right front wheel and a left front wheel, and the rear wheels 24 include two wheels, a right rear wheel and a left rear wheel. Figure 1 3 , a box-type trailer is exemplified as the trailer 30. The trailer 30 has wheels 32. The wheels 32 include two wheels, a right wheel and a left wheel.

[0025] The trailer 30 is connected to the rear part of the tractor 20 via a ball joint 40. The ball joint 40 is a member that connects the trailer 30 to the tractor 20 so as to be rotatable around a shaft 42. The shaft 42 extends in the height direction of the tractor 20.

[0026] Figure 2 FIG. 2 shows a part of the components of the tractor 20. Figure 2 As shown in FIG. 1 , the tractor 20 includes a control device 50. The control device 50 operates a steering system 60, a drive system 62, and a brake system 64 to control a control variable of the connected vehicle 10, which is a control object. The control variable is a vehicle speed, a driving direction, a towing angle, etc. The towing angle is an angle formed by the front-rear direction of the tractor 20 and the front-rear direction of the trailer 30.

[0027] The steering system 60 includes a steering actuator for steering a steering wheel. Figure 1 The front wheel 22 is shown. In addition, the steering system 60 may also include a steering control device that operates the steering actuator. In this case, "the control device 50 operates the steering system 60" means that the control device 50 outputs a command signal to the steering control device.

[0028] The drive system 62 includes at least one of an internal combustion engine and a rotary electric machine as thrust generating devices of the vehicle. In addition, the drive system 62 may also include a drive control device that controls the internal combustion engine and the rotary electric machine. In this case, "the control device 50 operates the drive system 62" means that the control device 50 outputs a command signal to the drive control device.

[0029] The brake system 64 includes at least one of a device for decelerating the rotation of the wheel by friction and a device for decelerating the rotation of the wheel by converting the power of the wheel into electrical energy. In addition, the device for decelerating the rotation of the wheel by converting into electrical energy can also be shared with the rotating motor of the drive system. In addition, the brake system 64 can also include a brake control device that controls the device for decelerating the rotation of the wheel. In this case, "the control device 50 operates the brake system 62" means that the control device 50 outputs a command signal to the brake control device.

[0030] The control device 50 refers to the steering angle α1 of the steering wheel detected by the steering angle sensor 70 in order to control the control amount. The steering angle α1 is a value whose sign is positive for either right turn or left turn and whose sign is negative for the other. The steering angle α1 is the rotation angle of the tire. In addition, for example, in the case where the steering system 60 has a rack and pinion mechanism, the steering angle sensor 70 can also be a sensor for detecting the gear angle. However, in this case, the control device 50 performs a process of converting the gear angle into the rotation angle of the tire. In the following, for the sake of convenience of explanation, even if the rotation angle of the tire is obtained by the above-mentioned conversion process, the rotation angle of the tire will be regarded as the detection value of the steering angle sensor 70.

[0031] In addition, the control device 50 refers to the towing angle β detected by the towing angle sensor 72. The towing angle β can take a positive or negative sign depending on the angle formed by the direction in which the tractor 20 moves from the rear to the front and the direction in which the trailer 30 moves from the rear to the front. For example, the sign of the towing angle β may be positive when the direction in which the trailer 30 moves from the rear to the front is offset by less than 180° counterclockwise relative to the direction in which the tractor 20 moves from the rear to the front. In addition, the control device 50 refers to the wheel speeds ωw1 to ωw4 detected by the wheel speed sensor 74. The wheel speeds ωw1 and ωw2 are the rotation speeds of the right front wheel 22 and the rotation speeds of the left front wheel 22, respectively. The wheel speeds ωw3 and ωw4 are the rotation speeds of the right rear wheel 24 and the rotation speeds of the left rear wheel 24, respectively. In addition, the control device 50 refers to the image data Dp representing the image behind the tractor 20 captured by the rear camera 76.

[0032] The control device 50 sets the control amount according to the operation state of the user interface 80. The user interface 80 is used to convey the user's intention to the control device 50, such as selecting either the automatic driving or the manual driving.

[0033] The control device 50 includes a PU 52 and a storage device 54. The PU 52 is a software processing device including at least one of a CPU, a GPU, and a TPU. The storage device 54 stores a reverse assist program 54a. The reverse assist program 54a is a program that specifies an instruction for causing the PU 52 to perform a reverse assist process. The reverse assist process is a process for automatically performing a steering process of the steering wheel during reverse driving of the coupled vehicle 10. The reverse assist program 54a is a program for reducing the load of the driver in reverse driving.

[0034] That is, Figure 3As shown, during the reverse travel of the coupled vehicle 10, even if the steering angle of the tractor 20 remains the same, the behavior of the trailer 30 changes according to the towing angle β. Therefore, the reverse control requires high driving skills. The reverse assist process by the reverse assist program 54a is a process for assisting the driver by controlling the steering angle α1 of the tractor 20. However, the accelerator operation and the brake operation are entrusted to the driver. In addition, the reverse assist process entrusts the driver with the instruction of the steering operation of the trailer 30. This is because when the control device 50 also sets the steering operation of the trailer 30, the requirements for the control device 50 become higher. By entrusting part of the instructions to the driver, the reverse control can be assisted by a relatively simple process.

[0035] "Model used in back-off assist processing"

[0036] Figure 4 2 shows a model of the connected vehicle 10 used in the reverse assist process. Figure 4 The model shown considers the pair of front wheels 22 of the tractor 20 as one front wheel C0, and the pair of rear wheels 24 of the tractor 20 as one rear wheel B1. That is, a two-wheel model is adopted for the tractor 20. In addition, the pair of wheels 32 of the trailer 30 are considered as one wheel B2. The angle formed by the line determined by the front wheel C0 and the hitch point C1 and the line determined by the hitch point C1 and the wheel B2 is the traction angle β. The hitch point C1 is equivalent to Figure 1 The front wheel speed VC0 is a vector moving in the direction of the steering angle α1. The steering angle α1 is modeled as the angle between the direction of the front wheel C0 and the line defined by the front wheel C0 and the hitch point C1. The direction of the vehicle speed Vb1 is parallel to the line defined by the front wheel C0 and the hitch point C1. In the following, the sign of the vehicle speed Vb1 when the tractor 20 is moving forward is set to be positive. Figure 4 The angle formed by the line connecting the wheel B2 and the attachment point C1 and the x direction is angle θ1. In addition, the angle formed by the line connecting the wheel B2 and the attachment point C1 and the x direction is angle θ2. In addition, the distance l1 between the front wheel C0 and the rear wheel B1, the distance h1 between the rear wheel B1 and the attachment point C1, and the distance l2 between the attachment point C1 and the wheel B2 are defined.

[0037] In this embodiment, the virtual steering angle α2 obtained by quantifying the steering of the trailer 30 is as follows: Figure 4 That is, it is defined as the angle formed by the direction of the moving speed of the hitch point C1 and the front-rear direction of the trailer 30 .

[0038] "Backward Assisted Processing"

[0039] Figure 5 and Figure 6 2 shows the order of the processing related to the back-up assist processing. Figure 5 and Figure 6 The processing shown is realized by the PU 52 repeatedly executing the back-up assisting program 54a at a predetermined cycle, for example. In the following, the step number of each processing is represented by a number with "S" at the beginning.

[0040] exist Figure 5 and Figure 6 In the series of processes shown, PU52 first determines whether the reverse assist flag F is "1" (S10). When the reverse assist flag F is "1", it indicates that it is a reverse assist mode for executing the reverse assist process. On the other hand, when the reverse assist flag F is "0", it indicates that it is not a reverse assist mode. When PU52 determines that the reverse assist flag F is "0" (S10: No), it determines whether it has become the reverse assist mode (S12). When the reverse assist process is indicated by the input operation of the user interface 80, PU52 determines that it is the reverse assist mode. When PU52 determines that it is the reverse assist mode (S12: Yes), it substitutes "1" for the reverse assist flag F (S14).

[0041] On the other hand, when the PU 52 determines that the reverse assist flag F is "1" (S10: YES), it determines whether the logical sum of the following conditions (A) and (B) is true (S16).

[0042] Condition (A): The condition that the back-up assist mode is canceled by an input operation on the user interface 80 .

[0043] Condition (B): The vehicle speed Vb1 is greater than or equal to the threshold value Vth. In other words, the forward speed of the tractor 20 is greater than or equal to the threshold value Vth. This process is a condition in which it is estimated that the driver stops the reverse control of the coupled vehicle 10 and causes the coupled vehicle 10 to move significantly.

[0044] When the PU 52 determines that the above logical sum is true ( S16 : Yes), it substitutes “0” into the reverse assist flag F ( S18 ).

[0045] On the other hand, when the PU 52 determines that the above logical sum is false (S16: No) and when the processing of S14 is completed, it obtains the target virtual steering angle α2* corresponding to the input operation to the user interface 80 (S20). The target virtual steering angle α2* is a target value of the virtual steering angle α2. In the present embodiment, the target virtual steering angle α2* is indicated by the driver. Specifically, for example, the input operation can also be realized by providing a dial that has a positive correlation with the virtual steering angle α2 on the user interface 80. Here, the rotation angle of the dial is not necessarily proportional to the target virtual steering angle α2*.

[0046] Next, PU52 uses the target virtual steering angle α2* as input to calculate the target trajectory Trt of the trailer 30 (S22). Here, PU52 uses a two-wheel model in which the attachment point C1 becomes the steering wheel, i.e., the front wheel, and the rear wheel B1 becomes the rear wheel to calculate the target trajectory Trt. In detail, PU52 calculates the target trajectory Trt by calculating the curvature of the target trajectory Trt based on the target virtual steering angle α2* and the distance l2. In addition, the target trajectory Trt is set to the trajectory of the representative point of the trailer 30. Here, the representative point may be, for example, the point in the center of the rear wheel B1. For another example, the representative point may also be the center of gravity of the trailer 30.

[0047] Next, PU52 obtains the traction angle β and the vehicle speed Vb1 (S24). The traction angle β is the latest detection value of the traction angle sensor 72. The vehicle speed Vb1 is calculated by PU52 based on the wheel speeds ωw3 and ωw4. The vehicle speed Vb1 may be, for example, a simple average value of the wheel speeds ωw3 and ωw4.

[0048] Next, PU52 calculates the speed Vb2 of wheel B2 (S25). Specifically, PU52 uses the geometric relationship between the traction angle β and the vehicle speed Vb1 to perform calculations. Next, PU52 initializes the angle θ1 (S26). Here, PU52 sets the angle θ1 to "90°". This is to make the front-rear direction of the tractor 20 Figure 4 The y-direction setting of the coordinate system shown.

[0049] Next, PU52 calculates the target steering angle α1*, which is the steering angle for achieving the target virtual steering angle α2* (S28). The process of S28 is a process that takes the target virtual steering angle α2* and the traction angle β as inputs and outputs the target steering angle α1*. Figure 4 In the model shown, the following equation (c1) holds true between the steering angle α1 and the virtual steering angle α2.

[0050] α1=arctan{(l1 / h1)·tan(-α2-β)}…(c1)

[0051] By replacing the virtual steering angle α2 on the right side of the above-mentioned equation (c1) with the target virtual steering angle α2*, the left side becomes the target steering angle α1*.

[0052] PU52 can also calculate the target steering angle α1* based on the formula corresponding to the above formula (c1). In addition, PU52 can also perform an image operation on the target steering angle α1*. This can be achieved by pre-storing image data in the storage device 54. Here, the image data is data that uses the target virtual steering angle α2* and the traction angle β as input variables, and the target steering angle α1* as an output variable. In addition, the image data is a group data of the discrete value of the input variable and the value of the output variable corresponding to each value of the input variable. In addition, the image operation can be set to the following processing: when the value of the input variable is consistent with any one of the values ​​of the input variables of the image data, the value of the output variable of the corresponding image data is used as the operation result. In addition, the image operation can be set to the following processing: when the value of the input variable is inconsistent with any one of the values ​​of the input variables of the image data, the value obtained by interpolating the values ​​of multiple output variables contained in the image data is used as the operation result. Alternatively, the image operation may be performed as follows: when the value of the input variable does not match any of the values ​​of the input variables of the image data, the value of the output variable of the image data corresponding to the closest value among the values ​​of the multiple input variables contained in the image data is used as the operation result.

[0053] Next, PU52 determines whether the target steering angle α1* is larger than the upper limit value α1th (S30). The upper limit value α1th is the maximum value of the possible magnitudes of the steering angle α1. This process is to determine whether the steering angle α1 that realizes the target virtual steering angle α2* can actually be realized. When PU52 determines that it is larger than the upper limit value α1th (S30: Yes), it reduces the magnitude of the target steering angle α1* to the upper limit value α1th (S32).

[0054] When the processing of S32 is completed or a negative determination is made in the processing of S30, the PU 52 controls the steering angle α1 by operating the steering system 60 so that the steering angle α1 approaches the target steering angle α1* (S34).

[0055] Move to Figure 6 PU52 predicts the traction angle β at a specified time τ in the future (S36).

[0056] according to Figure 4 In the model shown, the change amount Δβ of the traction angle β during a predetermined time τ is expressed by the following equation (c2).

[0057] Δβ=

[0058] -(Vb1 / l2)·sinβ·τ

[0059] -{Vb1 / (l1·l2)}·(l2+h1·cosβ)·(tanα1*)·τ

[0060] …(c2)

[0061] In the process of S36, PU52 may calculate the predicted value of the traction angle β based on the value obtained by adding the change Δβ calculated by the above-mentioned formula (c2) to the traction angle β. Alternatively, the process of S36 may be configured to include a process of calculating the change Δβ by using PU52 through a map operation in a state where map data is pre-stored. Here, the map data is data that takes the vehicle speed Vb1, the traction angle β, and the target steering angle α1* as input variables, and takes the change Δβ of the traction angle β as an output variable.

[0062] Next, the PU 52 calculates the angle θ1 at a predetermined time τ in the future (S38). Here, the change amount Δθ1 of the angle θ1 during the predetermined time τ is expressed by the following equation (c3).

[0063] Δθ1=(Vb1 / l1)·tan(α1*)…(c3)

[0064] In the process of S36, PU52 may also calculate the predicted value of angle θ1 based on the value obtained by adding the change Δθ1 calculated by the above-mentioned formula (c3) to the angle θ1. Alternatively, the process of S36 may also use PU52 to calculate the change Δθ1 by image operation in a state where image data is pre-stored. Here, the image data is data that uses the vehicle speed Vb1 and the target steering angle α1* as input variables and the change Δθ1 as an output variable.

[0065] Next, the PU 52 substitutes the sum of the traction angle β calculated by the process of S36 and the angle θ1 calculated by the process of S38 into the angle θ2 at a predetermined time τ in the future ( S40 ).

[0066] Next, PU52 uses the vehicle speed Vb1 and the angle θ1 as inputs, and calculates the tractor position coordinates (xb1, yb1) at a predetermined time τ in the future (S44). Here, the change amount of the x component xb1 of the tractor position coordinates within the predetermined time τ is "Vb1·cosθ1". In addition, the change amount of the y component yb1 of the tractor position coordinates within the predetermined time τ is "Vb1·sinθ1".

[0067] Next, PU52 uses the speed Vb2 and the angle θ2 as inputs and calculates the trailer position coordinates (xb2, yb2) at a predetermined time τ in the future (S46). Here, the change amount of the x component xb2 of the trailer position coordinates within the predetermined time τ is "Vb2·cosθ2". In addition, the change amount of the y component yb2 of the trailer position coordinates within the predetermined time τ is "Vb2·sinθ2".

[0068] Next, PU52 temporarily stores the values ​​calculated by the processes of S28 to S32 and S36 to S46 in the storage device 54 (S48). That is, PU52 temporarily stores the tractor position coordinates (xb1, yb1), trailer position coordinates (xb2, yb2), angles θ1, θ2, target steering angle α1*, and towing angle β in the storage device 54.

[0069] Then, PU52 determines whether the prediction interval has ended (S50). The prediction interval is an interval when the connected vehicle 10 travels for a predetermined time. The predetermined time can be set to about several seconds, for example. In addition, the prediction interval can have a positive correlation with the absolute value of the vehicle speed Vb1, but can also be set to be independent of the vehicle speed Vb1.

[0070] When the PU 52 determines that the prediction interval has not ended (S50: No), the process returns to S28. On the other hand, when the PU 52 determines that the prediction interval has ended (S50: Yes), the prediction trajectory Trp and the target trajectory Trt are displayed on the display. Figure 1 The display device 82 shown (S52). In addition, before the affirmative determination is made in the process of S50, it is preferable that the number of times the process of S34 is executed is actually set to once.

[0071] Here, at the time point when it is determined that the prediction interval has ended, the storage device 54 stores N traction angles β closer to the future than the traction angle β obtained by the process of S24. Here, N is an integer greater than 2. These are prediction values ​​at the time points separated from each other by a predetermined time τ. In addition, the storage device 54 stores the tractor position coordinates (xb1, yb1), the trailer position coordinates (xb2, yb2), the angles θ1, θ2, and the target steering angle α1* at the time points synchronized with the N traction angles β.

[0072] Here, the N trailer position coordinates (xb2, yb2) represent predicted positions of representative points of the trailer 30 separated from each other by a predetermined time τ. Therefore, by connecting them, the predicted trajectory Trp can be obtained.

[0073] The processing of S52 may be a processing of sending the N trailer position coordinates (xb2, yb2) to the display device 82. In addition, the processing of S52 may be a processing of finding a curve suitable for the N trailer position coordinates (xb2, yb2) and sending the parameters that determine the curve to the display device 82. In this case, the communication load can be reduced. In addition, the display device 82 may have only a simple display function, so that the PU52 generates an image displayed by the display device 82.

[0074] The display device 82 displays the predicted trajectory Trp and the target trajectory Trt in a superimposed manner on the image captured by the rear camera 76 .

[0075] Fig. 7A The predicted track Trp and the target track Trt obtained by connecting the trailer position coordinates (xb2, yb2) are shown in FIG. 1. By the process of S26, the trailer position coordinates (xb2, yb2) are coordinate components of a coordinate system whose y axis is parallel to the front-rear direction of the tractor 20. However, in order to match the image of the rear camera 76, the PU 52 Figure 7B As shown, point group data obtained by projecting the trailer position coordinates (xb2, yb2) is used as a display object.

[0076] Fig. 8A and Figure 8B An example of an image displayed on the display screen 82a of the display device 82 is shown in FIG. Fig. 8A The state of the connected vehicle 10 is shown in FIG. Figure 8B An example of a display screen 82a is shown in FIG. Fig. 8A and Figure 8B In FIG. 82 , the predicted trajectory Trp is shown by a solid line, and the target trajectory Trt is shown by a dashed line. However, in the actual display screen 82 a , the predicted trajectory Trp and the target trajectory Trt may be distinguished by changing the colors. Fig. 8A and Figure 8B The example shown shows a situation where it is desired to turn right while backing up.

[0077] Fig. 9A and Fig. 9B Another example of an image displayed on the display screen 82a of the display device 82 is shown in FIG. Fig. 9A and Fig. 9B and Fig. 8A and Figure 8B correspond. Fig. 9A and Fig. 9B The example shown shows a case where it is desired to shift from a state of turning right while backing up to a state of going straight.

[0078] Fig. 10A and Fig. 10BAnother example of an image displayed on the display screen 82a of the display device 82 is shown in FIG. Fig. 10A and Fig. 10B and Fig. 8A and Figure 8B correspond. Fig. 10A and Fig. 10B The example shown shows a situation where it is desired to turn from the right to the left while backing up. Fig. 10A and Fig. 10B In the example shown, the predicted trajectory Trp is greatly separated from the target trajectory Trt. This is caused by the processing of S30 to S32, and the predicted trajectory Trp does not change even if the target virtual steering angle α2* is manipulated by input operation to the user interface 80. The situation in which the predicted trajectory Trp does not change is as follows. Fig.11A and Fig. 11B As shown, this is likely to occur when the pulling angle β is large.

[0079] Fig.11A The example in which the target virtual steering angle α2* is reset when the magnitude of the traction angle β is small is shown. Fig. 11B The example in which the target virtual steering angle α2* is reset when the magnitude of the traction angle β is small is shown.

[0080] like Fig.11A and Fig. 11B As shown in FIG. 1 , if the target virtual steering angle α2* is reset in a state where the magnitude of the traction angle β is large, the virtual steering angle α2 cannot follow the target virtual steering angle α2*.

[0081] In this way, when the predicted trajectory Trp does not change even if the target virtual steering angle α2* is operated, the driver may be confused as to why the predicted trajectory Trp does not change. In contrast, in the present embodiment, by displaying the target trajectory Trt together, when the difference between the target trajectory Trt and the predicted trajectory Trp is large, it is possible to notify that the virtual steering angle α2 cannot be set to a desired angle due to the steering of the tractor 20.

[0082] According to the present embodiment described above, the following operations and effects can also be obtained.

[0083] (1) The PU 52 sets one of the axes of the coordinate system that determines the trailer coordinate component to be parallel to the front-rear direction of the tractor 20 at each time. This makes it possible to easily integrate the trailer coordinate component with the image of the rear camera 76.

[0084] (2) The PU 52 performs a projection transformation on the trailer coordinate component. This allows the trailer coordinate component to be appropriately integrated with the image of the rear camera 76 .

[0085] (3) PU52 uses the target steering angle α1*, whose magnitude is limited to be less than the upper limit value α1th, as input and calculates the predicted trajectory of the trailer 30. In other words, PU52 calculates the predicted trajectory of the trailer 30 when the actual virtual steering angle α2 is brought as close as possible to the target virtual steering angle α2* within the range where the magnitude of the steering angle α1 is less than the upper limit value α1th. Here, the virtual steering angle α2 can be controlled according to the steering of the tractor 20, but the possible range of the virtual steering angle α2 is limited by the possible range of the steering angle α1. Therefore, PU52 calculates the predicted trajectory of the trailer 30 when the actual virtual steering angle α2 is brought as close as possible to the target virtual steering angle α2* within the range where the magnitude of the steering angle α1 is less than the upper limit value α1th. In this way, the predicted trajectory can be made a trajectory that the trailer 30 can achieve.

[0086] (4) The PU 52 executes processing for displaying the target trajectory of the trailer vehicle 30 when the virtual steering angle α2 is set as the target virtual steering angle α2*.

[0087] In the coupled vehicle 10, when the magnitude of the towing angle β increases to a certain extent, there is a tendency that the behavior of the trailer 30 hardly changes no matter how the steering angle α1 is set. In this case, although the driver greatly changes the target virtual steering angle α2*, the displayed predicted track hardly changes. In such a situation, there is a concern that the driver will be at a loss as to what to do when the predicted track does not change despite the change in the target virtual steering angle α2*. In contrast, PU52 also displays the target track determined by ignoring the possible range of the steering angle α1. Even in a situation where the behavior of the trailer 30 hardly changes no matter how the steering angle α1 is set, the target track changes greatly according to the change in the target virtual steering angle α2*. Therefore, by the divergence between the predicted track and the target track, the driver can be notified that the behavior of the trailer 30 hardly changes no matter how the steering angle α1 is set.

[0088] (5) PU52 controls the target steering angle α1* so that the target steering angle α1* is equal to or less than the upper limit α1th and the steering angle α1 is brought close to the target steering angle α1*, thereby bringing the virtual steering angle α2 close to the target virtual steering angle α2*. Thus, the target steering angle α1* can be set to a value that tries to achieve the target virtual steering angle α2* under the condition that the target steering angle α1* is equal to or less than the upper limit α1th.

[0089] (6) PU52 uses the target steering angle α1* that has been subjected to the upper limit protection process as input to predict the future value of the traction angle β. In addition, PU52 repeatedly performs three processes: using the predicted traction angle β as input to calculate the target steering angle α1*, using the target steering angle α1* that has been subjected to the upper limit protection process as input to predict the traction angle β, and using the predicted traction angle β and the target steering angle α1* that has been subjected to the upper limit protection process as input to predict the displacement of the trailer 30. There is a prescribed correlation between the virtual steering angle α2, the traction angle β, and the steering angle α1. Therefore, if the traction angle β changes, the target steering angle α1* that realizes the target virtual steering angle α2* changes. Therefore, by performing the above three processes multiple times, PU52 can calculate a relatively long predicted trajectory with high accuracy.

[0090] (7) The PU 52 performs the processing of assisting the steering and the processing of displaying the above-mentioned track in the reverse assist mode.

[0091] The reverse control of the coupled vehicle 10 requires a high level of driving skill. In this regard, the PU 52 can reduce the burden on the driver to steer the tractor 20 by executing the auxiliary steering process in the reverse assist mode. In addition, the above-mentioned display process can provide useful information when the driver instructs the direction of travel of the trailer 30.

[0092] (8) The PU 52 continues the above-described display processing even when the coupled vehicle 10 switches from reverse movement to forward movement in the reverse assist mode.

[0093] When the behavior of the trailer 30 is inappropriate during the reverse control of the coupled vehicle 10, the driver may restart the reverse control by advancing the coupled vehicle 10. In this case, by continuing the displayed process, the driver can understand where to advance so that the desired behavior of the trailer 30 can be achieved.

[0094] (9) When the forward traveling speed of the coupled vehicle 10 is equal to or higher than the threshold value Vth, the PU 52 cancels the reverse assist mode.

[0095] When the forward travel speed is high, it is considered that the driver does not want the reverse control but wants to move the connected vehicle 10. Therefore, the PU 52 cancels the reverse assist mode when the forward travel speed is greater than the threshold value Vth, thereby saving the driver the trouble of manually canceling the reverse assist mode.

[0096] (10) The PU 52 superimposes the predicted trajectory information on the image of the exterior of the coupled vehicle 10 captured by the rear camera 76. By superimposing the predicted trajectory information on the image of the rear camera 76 in this way, the behavior of the trailer 30 can be easily and accurately grasped.

[0097] <Other embodiments>

[0098] In addition, the present embodiment can be implemented by changing the following aspects. The present embodiment and the following modified examples can be implemented in combination with each other within the scope of no technical contradiction.

[0099] "About status quantity acquisition processing"

[0100] In the process of S24, the PU 52 obtains the traction angle β detected by the traction angle sensor 72, but the present invention is not limited to this. For example, the PU 52 may obtain an estimated value of the traction angle β. This can be achieved by the PU 52 estimating that the traction angle β is zero at a time point when the straight-line travel continues for a predetermined distance, and then sequentially updating the traction angle β using the change Δβ obtained using the above-mentioned formula (c2). In addition, here, the change Δβ is an estimated value of the change, not a predicted value of the change in the future traction angle β.

[0101] "About Virtual Steering Angle"

[0102] The virtual steering angle, which is a variable for quantifying the steering of the trailer, is not limited to the definition given in the above embodiment. For example, the virtual steering angle may be defined as the angle between the front-rear direction of the tractor 20 and the traveling direction of the hitch point C1.

[0103] "About the calculation and processing of predicted orbit information"

[0104] For the processing of calculating the predicted trajectory of the trailer 30 when the actual virtual steering angle α2 is as close as possible to the target virtual steering angle α2* within the range of the steering angle α1 being below the upper limit value α1th, the processing of S30, S32 and the like is not necessary. The processing of calculating the above-mentioned predicted trajectory may also include, for example, a processing of converting the upper limit value α1th into the upper limit value of the size of the virtual steering angle α2 based on a formula obtained by reversing the above-mentioned formula (c1). In this case, PU52 uses the upper limit value of the size of the virtual steering angle α2 to perform upper limit protection processing on the target virtual steering angle α2*. Moreover, PU52 uses the value obtained by converting the target virtual steering angle α2* that has been subjected to the upper limit protection processing into the target steering angle α1* using the above-mentioned formula (c1), and performs the processing below S34.

[0105] PU52 does not necessarily need to set the initial value of angle θ1 to "90°" in the prediction of the track. For example, PU52 may compare the map data with the front-rear direction of the tractor 20 and use the angle formed by a predetermined axis in a coordinate system arbitrarily determined on the map data and the front-rear direction of the tractor 20 as the initial value of angle θ1 in the calculation process of the predicted track information.

[0106] “About steering handling”

[0107] The steering process for controlling the steering angle α1 so that the virtual steering angle α2 approaches the target virtual steering angle α2* is not limited to the process executed in the reverse assist mode. For example, the process of automatically steering the tractor 20 during forward driving of the coupled vehicle 10 may be used.

[0108] "Conditions for cancelling the diversion process"

[0109] In the above embodiment, as the release condition of the steering process, i.e., the release condition of the reverse assist mode, the condition that the logical sum of condition (A) and condition (B) is true is exemplified, but the present invention is not limited thereto. For example, the condition that the connected vehicle 10 has moved forward may be used instead of the above condition (B). In addition, for example, the release condition may be set to only condition (A).

[0110] About Display Processing

[0111] It is not necessary for PU52 to display the target track Trt in addition to the predicted track Trp of the trailer 30. PU52 may also display an area that can be realized as the driving track of the trailer 30, for example, while displaying only the predicted track Trp. In this case, when the driving path of the trailer 30 hardly changes even if the steering angle α1 is changed, the width of the above-mentioned area becomes narrower. Therefore, it is possible to notify the driver that it is difficult to change the driving track of the trailer 30 even if the virtual steering angle α2 is changed. In addition, for example, PU52 may replace the display of the above-mentioned area and notify that it is difficult to change the track of the trailer 30 through operation when the width of the area is less than a specified value and the driver operates the target virtual steering angle α2*. This processing may be a processing of displaying visual information or a processing of notifying by sound.

[0112] For example Figures 8A to 9B As in the case illustrated in , when the difference between the predicted trajectory Trp and the target trajectory Trt is below a prescribed value, only the predicted trajectory Trp may be displayed by PU52. That is, when PU72 sequentially determines whether the difference between the predicted trajectory Trp and the target trajectory Trt is below a prescribed value and determines that it is below a prescribed value, the target trajectory Trt is not displayed. Here, the difference between the predicted trajectory Trp and the target trajectory Trt is below a prescribed value, for example, may be the average value of the difference between the positions of each of the predicted trajectory Trp and the target trajectory Trt at the same time being below a prescribed value. For example, the difference between the positions of each of the predicted trajectory Trp and the target trajectory Trt at the same time may not exceed a prescribed value.

[0113] The predicted trajectory information to be displayed is not limited to the predicted trajectory Trp. Fig. 12A and Fig. 12B As shown in the example, the prediction track Trp may also have a width. Fig. 12A and Fig. 12B and Fig. 8A and Figure 8B Corresponding. Fig. 12A and Fig. 12B In the display screen 82a, the area determined by the boundaries TrpL and TrpR of a pair of predicted tracks is displayed as dots. In addition, the area determined by the boundaries TrtL and TrtR of a pair of target tracks is shaded. However, in the actual display screen 82a, the two areas may be distinguished by different colors.

[0114] The process of making the predicted track Trp have width can be implemented as follows, for example, depending on whether a negative judgment is made in the process of S30. That is, when PU52 makes a negative judgment in the process of S30, it uses the target steering angle α1* calculated by the process of S28 and executes the processes of S36 to S46 using each of "α1*+δ" and "α1*-δ". In addition, when PU52 makes a negative judgment in the process of S30, it can execute the processes of S36 to S46 using, for example, the target steering angle α1* calculated by the process of S32 and each of the values ​​whose absolute value is smaller than the target steering angle by a specified amount.

[0115] The process of making the target track Trt have a width may be a process of calculating the boundaries TrtL and TrtR as follows. That is, the process may be a process of calculating the boundaries TrtL and TrtR by the process of S22 using each of "α2*+δ" and "α2*-δ" determined by the target virtual steering angle α2* obtained by the process of S20.

[0116] In addition, when the process of making the predicted track Trp have a width is executed, it is not necessary to execute the process of making the target track Trt have a width. For example, a single track may be made the display object for the target track Trt. In addition, when the process of making the predicted track Trp have a width is executed, the PU 52 may not display any visual information related to the target track Trt.

[0117] For example, as described in the column “Regarding Steering Processing”, when the steering is automatically controlled while the coupled vehicle 10 is traveling forward, the PU 52 may superimpose the predicted trajectory Trp of the tractor 20 on the image in front of the tractor 20 .

[0118] The process of displaying the predicted trajectory Trp is not limited to superimposing the predicted trajectory Trp on the image of the surroundings of the connected vehicle 10 obtained by the camera. Fig.13A and Fig. 13B As shown in FIG. 1 , a bird's eye view may be used. Thus, the behavior of the trailer 30 can be viewed from above. Fig.13A and Fig. 13B and Fig. 8A and Figure 8B This is particularly effective in the reverse assist process in the connected vehicle 10 having a predetermined trailer 30 such as a camper. Figure 1 As shown by the dashed line in FIG. 8 , when the height of the trailer 30 is high, the rear of the trailer 30 cannot be moved to the image captured by the rear camera 76 .

[0119] The predicted track information to be superimposed on the bird's-eye view is not limited to the predicted track Trp. For example, as described above, a region obtained by giving the predicted track Trp a width may be superimposed on the bird's-eye view and displayed.

[0120] The predicted track information of the trailer 30 may also be displayed, and the predicted track information of the tractor 20 may also be displayed. Fig.14A and Fig. 14B In FIG. 1 , the predicted trajectory Trp and the target trajectory Trt are superimposed on the bird's-eye view, and the predicted trajectory Tr1L at the left end and the predicted trajectory Tr1R at the right end of the tractor 20 are displayed. Fig.14A and Fig. 14B and Fig. 8A and Figure 8B Corresponding. In addition, the method of displaying the predicted track of the tractor 20 is not limited to the method of displaying both the predicted track Tr1L at the left end and the predicted track Tr1R at the right end. For example, a method of displaying a single predicted track such as the predicted track of the center of gravity of the tractor 20 may be used. In addition, an area having a width such as marking the area between the predicted track Tr1L at the left end and the predicted track Tr1R at the right end may be displayed.

[0121] In addition, the method of displaying the predicted track information of the trailer 30 and the predicted track information of the tractor 20 does not necessarily require the use of a bird's-eye view. For example, the PU 52 may superimpose the predicted track information of the trailer 30 and the predicted track information of the tractor 20 on an image obtained by photographing the outside of the coupled vehicle 10. In such processing, the target track information of the trailer 30 does not necessarily need to be displayed at the same time.

[0122] The predicted track information of the trailer 30 to be displayed is not necessarily the predicted track Trp or the area that makes the predicted track Trp have a width. For example, when the manual steering of the connected vehicle 10 is operated, when the moving direction of the trailer 30 is not straight, the arrow on the right or left side indicating the moving direction of the trailer 30 may be displayed.

[0123] About the Control Device

[0124] The control device is not limited to a structure having PU52 and storage device 54 to perform software processing. For example, it may also be provided with a dedicated hardware circuit such as ASIC that performs hardware processing on at least a part of the various processes performed in the above-mentioned embodiments. That is, the control device may be any one of the following structures (a) to (c). (a) A processing circuit having a processing device that performs all the above-mentioned processes according to a program, and a program storage device such as a storage device that stores the program. (b) A processing circuit having a processing device and a program storage device that perform a part of the above-mentioned processes according to a program, and a dedicated hardware circuit that performs the remaining processes. (c) A processing circuit having a dedicated hardware circuit that performs all the above-mentioned processes. Here, there may be multiple software execution devices and dedicated hardware circuits having a processing device and a program storage device.

[0125] About Computer

[0126] The computer that executes the control program such as the back-up assist program 54a is not limited to the computer mounted on the connected vehicle 10. For example, the computer may be composed of both the PU 52 mounted on the connected vehicle 10 and the driver's mobile terminal. In this case, for example, the mobile terminal may also execute the processing of S28 to S32 and S36 to S50.

[0127] "About Vehicles"

[0128] As a connected vehicle, not limited to Figure 1 The vehicle illustrated in FIG.

Claims

1. A control device for a coupled vehicle, comprising a tractor and a trailer towed by the tractor, characterized in that: The control device is configured to execute state quantity acquisition processing, predicted trajectory information calculation processing, and display processing, The state quantity acquisition process is a process for acquiring the state quantity of the connected vehicle. The predicted track information calculation process is a process of calculating the predicted track information of the trailer based on the state quantity. The display process is a process of displaying the predicted trajectory information by operating a display device.

2. The vehicle-connected control device according to claim 1, characterized in that: The connected vehicle has an interface for the driver to indicate a target virtual steering angle. The target virtual steering angle is a target value of the virtual steering angle. The virtual steering angle is a variable indicating the direction of travel of the connection portion between the trailer and the tractor. The control device is configured to execute a target virtual steering angle acquisition process and a steering process. The target virtual steering angle acquisition process is a process of acquiring the target virtual steering angle according to the input operation of the driver to the interface. The predicted trajectory information calculation process is a process of calculating the predicted trajectory of the trailer when the actual virtual steering angle is brought as close to the target virtual steering angle as possible within a range where the steering angle of the tractor is below an upper limit value by taking the virtual steering angle as an input. The display process is a process of displaying the predicted trajectory. The steering process is a process of controlling the steering angle of the tractor vehicle so that the virtual steering angle approaches the target virtual steering angle.

3. The vehicle-connected control device according to claim 2, characterized in that: The control device is configured to perform target trajectory calculation processing, The target trajectory calculation process is a process of taking the target virtual steering angle as an input and calculating a target trajectory, which is the trajectory of the trailer vehicle when the virtual steering angle is used as the target virtual steering angle. The display process includes a process of displaying the target trajectory in addition to the predicted trajectory.

4. The vehicle-connected control device according to claim 2, characterized in that: The state quantity acquisition process includes a process of acquiring a traction angle. The towing angle is the angle between the front-rear direction of the tractor and the front-rear direction of the trailer. The predicted trajectory information calculation process includes target steering angle calculation process, upper limit protection process and displacement prediction process. The target steering angle calculation process includes a process of calculating a target steering angle, which is a target value of the steering angle of the tractor, by taking the target virtual steering angle and the traction angle as inputs. The upper limit protection process is a process of setting the target steering angle to the upper limit value when the target steering angle exceeds the upper limit value. The displacement prediction process includes a process of predicting the displacement of the trailer using the target steering angle for which the upper limit protection process has been implemented as an input, The steering process includes a process of bringing the virtual steering angle closer to the target virtual steering angle by bringing the steering angle closer to the target steering angle.

5. The vehicle-connected control device according to claim 4, characterized in that: The control device is configured to perform a hitch angle prediction process, The hitch angle prediction process is a process of predicting a future value of the hitch angle by taking the target steering angle on which the upper limit guard process has been implemented as an input. The control device is configured to perform three processes multiple times: the target steering angle calculation process using the predicted traction angle as input, the traction angle prediction process using the target steering angle for which the upper limit protection process has been implemented as input, and the displacement prediction process using the predicted traction angle and the target steering angle for which the upper limit protection process has been implemented as input.

6. The vehicle-connected control device according to claim 2, characterized in that: The control device is configured to perform a determination process, The determination process is a process for determining whether the vehicle is in the reverse assist mode. The reverse assist mode is a process of realizing the reverse process of the connected vehicle by the steering process. The control device is configured to execute the display process in the reverse assist mode.

7. The vehicle-connected control device according to claim 6, characterized in that: The control device is configured to continue the display process even when the connected vehicle switches from moving backward to moving forward in the reverse assist mode.

8. The vehicle-connected control device according to claim 7, characterized in that: The control device is configured to execute a cancellation process, The cancellation process is a process of canceling the reverse assist mode when the forward traveling speed of the coupled vehicle is equal to or greater than a threshold value.

9. The vehicle-connected control device according to claim 1, characterized in that: The display processing includes a process of superimposing the predicted trajectory information on an image of the exterior of the connected vehicle captured by a camera.

10. The vehicle-connected control device according to claim 1, characterized in that: The display processing includes a process of superimposing the predicted trajectory information on a bird's-eye view of the vicinity of the connected vehicle.

11. A method for controlling a coupled vehicle, comprising a tractor and a trailer towed by the tractor, characterized in that: The control method includes the steps of executing a state quantity acquisition process, a predicted trajectory information calculation process, and a display process. The state quantity acquisition process is a process for acquiring the state quantity of the connected vehicle. The predicted track information calculation process is a process of calculating the predicted track information of the trailer based on the state quantity. The display process is a process of displaying the predicted trajectory information by operating a display device.

12. A control program for a coupled vehicle, comprising a tractor and a trailer towed by the tractor, characterized in that: The control program is a program that causes a computer to execute state quantity acquisition processing, predicted trajectory information calculation processing, and display processing. The state quantity acquisition process is a process for acquiring the state quantity of the connected vehicle. The predicted track information calculation process is a process of calculating the predicted track information of the trailer based on the state quantity. The display process is a process of displaying the predicted trajectory information by operating a display device.

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