Device for preventing jackknife movement of articulated vehicles, method for preventing jackknife movement of articulated vehicles, and program for preventing jackknife movement of articulated vehicles

Abstract

A jackknife countermeasure device for a coupled vehicle (50) is configured to execute determination processing and countermeasure processing. The determination processing is processing for determining whether a logical product of the following is positive: a magnitude of a value of a steering angle variable being greater than or equal to a prescribed value; the value of the steering angle variable being a value of one of right turning and left turning and a value of a hitch angle variable being a value of the other of the right turning and the left turning; and an increase speed of the magnitude of the value of the hitch angle variable being greater than or equal to a threshold. The steering angle variable is a variable that expresses a steering angle of a steering wheel of the coupled vehicle. The hitch angle variable is a variable that expresses an angle formed between a front-back direction of a tractor and a front-back direction of a trailer. The countermeasure processing is processing for countering jackknifing, and is executed when a determination is made that the logical product is positive at a time of backing up of the coupled vehicle.

Description

[Technical Field]

[0001] The present disclosure relates to an anti-jackknife device for articulated vehicles, an anti-jackknife method for articulated vehicles, and an anti-jackknife program for articulated vehicles. [Background technology]

[0002] For example, Patent Document 1 listed below describes a device that determines whether an articulated vehicle has fallen into a jackknife state. This device determines whether an articulated vehicle has fallen into a jackknife state using a model of the articulated vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 9,229,452 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there are many different types of trailers that can be coupled to a tractor, and therefore the model used to determine a jackknife condition must be changed depending on the type of trailer. [Means for solving the problem]

[0005] One aspect of the present disclosure provides a jackknife prevention device for an articulated vehicle in which a tractor and a trailer are coupled together. The jackknife prevention device is configured to execute an acquisition process, a determination process, and a countermeasure process. The acquisition process is a process for acquiring a value of a steering angle variable and a value of a hitch angle variable. The steering angle variable is a variable indicating the steering angle of steered wheels of the articulated vehicle. The hitch angle variable is a variable indicating the angle between the longitudinal direction of the tractor and the longitudinal direction of the trailer. The determination process is a process for determining whether a logical product of the following is true: the magnitude of the value of the steering angle variable is equal to or greater than a predetermined value; the value of the steering angle variable is a value indicating either a right turn or a left turn and the value of the hitch angle variable is a value indicating the other of the right turn or the left turn; and the rate of increase in the magnitude of the value of the hitch angle variable is equal to or greater than a threshold. The countermeasure process is a process for countering a jackknife phenomenon that is executed when the logical product is determined to be true while the articulated vehicle is traveling backward.

[0006] Another aspect of the present disclosure provides a method for countering jackknife phenomena in an articulated vehicle having a tractor and a trailer connected together. The method for countering jackknife phenomena in an articulated vehicle includes executing an acquisition process, a determination process, and a countermeasure process. The acquisition process is a process for acquiring a value of a steering angle variable and a value of a hitch angle variable. The steering angle variable is a variable indicating the steering angle of the steered wheels of the articulated vehicle. The hitch angle variable is a variable indicating the angle between the longitudinal direction of the tractor and the longitudinal direction of the trailer. The determination process is a process for determining whether a logical product of the following is true: the magnitude of the value of the steering angle variable is equal to or greater than a predetermined value; the value of the steering angle variable is a value indicating either a right turn or a left turn and the value of the hitch angle variable is a value indicating the other of the right turn or the left turn; and the rate of increase in the magnitude of the value of the hitch angle variable is equal to or greater than a threshold. The countermeasure process is a process for countering jackknife phenomena that is executed when the logical product is determined to be true while the articulated vehicle is traveling backward.

[0007] Another aspect of the present disclosure provides a jackknife countermeasure program for an articulated vehicle in which a tractor and a trailer are coupled together. The jackknife countermeasure program has instructions for causing a computer to execute an acquisition process, a determination process, and a countermeasure process. The acquisition process is a process for acquiring a value of a steering angle variable and a value of a hitch angle variable. The steering angle variable is a variable indicating the steering angle of the steered wheels of the articulated vehicle. The hitch angle variable is a variable indicating the angle between the longitudinal direction of the tractor and the longitudinal direction of the trailer. The determination process is a process for determining whether a logical product of the following is true: the magnitude of the value of the steering angle variable is equal to or greater than a predetermined value; the value of the steering angle variable is a value indicating either a right turn or a left turn and the value of the hitch angle variable is a value indicating the other of the right turn or the left turn; and the rate of increase in the magnitude of the value of the hitch angle variable is equal to or greater than a threshold. The countermeasure process is a process for countering a jackknife phenomenon that is executed when the logical product is determined to be true while the articulated vehicle is traveling backward. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an articulated vehicle according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a control system in the articulated vehicle shown in FIG. [Figure 3] FIG. 3 is a flowchart showing the procedure of the process executed by the control device in the control system shown in FIG. [Figure 4] FIG. 4 is a diagram showing a model of the articulated vehicles shown in FIG. [Figure 5] FIG. 5 is a flowchart showing the procedure of the process executed by the control device shown in FIG. [Figure 6] 6A and 6B are diagrams showing the articulated vehicle shown in FIG. 1 in a jackknife state. [Figure 7] FIG. 7 is a diagram showing the principle of jackknife detection. [Figure 8] FIG. 8 is a flowchart showing the procedure of the process executed by the control device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment The first embodiment will be described below with reference to the drawings. As shown in Figure 1, the articulated vehicle 10 has a tractor 20 and a trailer 30. The tractor 20 has 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 also shows an example of a box-shaped trailer as the trailer 30. The trailer 30 has wheels 32. The wheels 32 include two wheels, a right wheel and a left wheel.

[0010] The trailer 30 is connected to the rear 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 that the trailer 30 can rotate about an axis 42. The axis 42 extends along the height direction of the tractor 20.

[0011] Figure 2 shows some of the components provided on the tractor 20. As shown in Figure 2, the tractor 20 is equipped with a control device 50. The control device 50 operates a steering system 60, a drive system 62, and a braking system 64 to control the control variables of the articulated vehicle 10, which is the control target. The control variables include vehicle speed, traveling direction, and hitch angle. The hitch angle is the angle formed between the fore-and-aft direction of the tractor 20 and the fore-and-aft direction of the trailer 30.

[0012] Steering system 60 includes a steering actuator that steers the steered wheels. The steered wheels are, for example, front wheels 22 shown in FIG. 1. In this embodiment, as an example, steering system 60 includes a steering control device that operates the steering actuator. And, "control device 50 operates steering system 60" means that control device 50 outputs a command signal to the steering control device.

[0013] The drivetrain 62 includes at least one of an internal combustion engine and a rotating electric machine as a thrust generating device for the vehicle. The drivetrain 62 may also include a drive control device that controls the internal combustion engine and the rotating electric machine. In this case, "the control device 50 operates the drivetrain 62" means that the control device 50 outputs a command signal to the drive control device.

[0014] The braking system 64 includes at least one of a device that decelerates the rotation of the wheels by frictional force and a device that decelerates the rotation of the wheels by converting the power of the wheels into electrical energy. The device that decelerates the rotation of the wheels by converting it into electrical energy may be shared with the rotating electric machine of the drive system. The braking system 64 may also include a braking control device that controls the device that decelerates the rotation of the wheels. In this case, "the control device 50 operates the braking system 64" means that the control device 50 outputs a command signal to the braking control device.

[0015] To control the control variable, the control device 50 refers to the steering angle α1 of the steered wheels detected by the steering angle sensor 70. The steering angle α1 is a value in which either the right turn or the left turn has a positive sign and the other has a negative sign. The steering angle α1 is the turning angle of the tires. Note that, for example, if the steering system 60 is equipped with a rack and pinion mechanism, the steering angle sensor 70 may be a sensor that detects the pinion angle. In this case, however, the control device 50 performs a process to convert the pinion angle into the turning angle of the tires. For convenience of explanation, the turning angle of the tires obtained by the above conversion process will be considered to be the detection value of the steering angle sensor 70 below.

[0016] The control device 50 also references the hitch angle β detected by the hitch angle sensor 72. The hitch angle β can have either a positive or negative sign depending on the angle formed between the direction in which the tractor 20 moves from rear to front and the direction in which the trailer 30 moves from rear to front. For example, the sign of the hitch angle β may be positive when the direction in which the trailer 30 moves from rear to front deviates counterclockwise from the direction in which the tractor 20 moves from rear to front by less than 180 degrees.

[0017] The control device 50 sets the control of the control amount according to the operation state of the user interface 80. The user interface 80 is used to communicate the user's intention to the control device 50, such as selecting either automatic driving or manual driving.

[0018] The control device 50 comprises a PU 52 and a storage device 54. The PU 52 is a software processing device comprising at least one of a CPU, a GPU, a TPU, etc. A reverse assist program 54a is stored in the storage device 54. The reverse assist program 54a is a program that prescribes commands for causing the PU 52 to execute reverse assist processing. The reverse assist processing is processing that automatically performs steering processing of the steered wheels when the combination vehicle 10 is traveling in reverse. The reverse assist program 54a is a program that reduces the burden on the driver when driving in reverse.

[0019] In other words, when the combination vehicle 10 is traveling in reverse, even if the steering angle α1 of the tractor 20 is the same, the behavior of the trailer 30 changes depending on the hitch angle β. For this reason, high driving skill is required for reverse control. The reverse assist process by the reverse assist program 54a is a process that assists the driver by controlling the steering angle α1 of the tractor 20. However, the reverse assist process leaves instructions for steering the trailer 30 to the driver. This is because if the control device 50 also sets the steering of the trailer 30, it would place greater demands on the control device 50. By leaving some instructions to the driver, reverse control can be performed with relatively simple processing.

[0020] "Steering during reverse assist processing" The procedure for the reverse assist process is shown in Figure 3. The process shown in Figure 3 is realized by the PU 52 repeatedly executing the reverse assist program 54a, for example, at a predetermined interval. Note that, hereinafter, the step numbers of each process are represented by numbers preceded by "S."

[0021] 3, the PU 52 first determines whether the vehicle is in the reverse assist mode (S10). If the PU 52 determines that the vehicle is in the reverse assist mode (S10: YES), the PU 52 acquires the hitch angle β detected by the hitch angle sensor 72 (S12). The PU 52 also acquires the steering angle α1 detected by the steering angle sensor 70 (S14).

[0022] Then, the PU 72 calculates a virtual steering angle α2 using the steering angle α1 and the hitch angle β as inputs (S16). The virtual steering angle α2 is a variable that indicates the traveling direction of the connection point between the trailer 30 and the tractor 20. In other words, it is a variable that indicates the traveling direction of the shaft 42 shown in Figure 1. In this embodiment, as an example, the virtual steering angle α2 is defined by the angle that the traveling direction of the ball joint 40 makes with respect to the fore-and-aft direction of the trailer 30.

[0023] Here, the reason why the virtual steering angle α2 is calculated from the turning angle α1 and the hitch angle β will be explained with reference to FIG. FIG. 4 shows a model of the articulated vehicle 10 used in this embodiment. In the model shown in FIG. 4, the pair of front wheels 22 of the tractor 20 are considered to be one front wheel C0, and the pair of rear wheels 24 of the tractor 20 are considered to be one rear wheel B1. In other words, a two-wheel model is used for the tractor 20. In addition, in the model shown in FIG. 4, the pair of wheels 32 of the trailer 30 are considered to be one wheel B2. The angle between a line defined by the front wheel C0 and hitch point C1 and a line defined by the hitch point C1 and wheel B2 is the hitch angle β. The hitch point C1 corresponds to the axle 42 in FIG. 1. Furthermore, the front wheel speed VC0, which is the speed of the front wheel C0, is a vector that moves in the direction of the steering angle α1. The steering angle α1 is quantified as the angle between the direction of travel of the front wheel C0 and the line defined by the front wheel C0 and hitch point C1. The direction of vehicle speed V is parallel to the line defined by the front wheel C0 and hitch point C1. The angle between the direction of vehicle speed V and the x direction in FIG. 4 is θ1. The angle between the line connecting wheel B2 and hitch point C1 and the x direction is θ2. Distance l1 is the length between the front wheel C0 and rear wheel B1. Distance h1 is the length between the rear wheel B1 and hitch point C1.

[0024] According to the above definition, the virtual steering angle α2 is the angle between the direction of travel from wheel B2 to hitch point C1 and the direction of the speed VC1 of hitch point C1. Using the angle γ1 between the direction of travel from hitch point C1 to front wheel C0 and the direction of the speed VC1 of hitch point C1, the virtual steering angle α2 can be expressed as "-(β-γ1)".

[0025] In the model shown in FIG. 4, the following equations (c1) to (c3) are established using the coordinates (xc0, yc0) of the front wheel C0, the coordinates (xb1, yb1) of the rear wheel B1, and the coordinates (xc1, yc1) of the hitch point C1.

[0026] VC0·cosα1=VB1 …(c1) xc0=xb1+l1·cosθ1 …(c2) xc1=xb1-h1·cosθ1 …(c3) By differentiating both sides of the above equations (c2) and (c3) and using equation (c1), we obtain the following equation (c4).

[0027] h1·tanα1+l1·tanγ1=0 …(c4) According to the above formula (c4), the angle γ1 can be expressed by the steering angle α1. Therefore, the virtual steering angle α2 is expressed by the following formula (c5).

[0028] α2=-β-arctan{(h1 / l1)·tan(α1)} …(c5) That is, the virtual steering angle α2 can be calculated from the hitch angle β and the steering angle α1. The process of S16 shown in Fig. 3 may be a process using the above-mentioned formula (c5). Alternatively, the process of S16 may be a process in which the PU 52 performs map calculation of the virtual steering angle α2 by using map data stored in the storage device 54. The map data is data in which the hitch angle β and the steering angle α1 are input variables and the virtual steering angle α2 is an output variable.

[0029] Here, map data refers to a set of data consisting of discrete values ​​of input variables and values ​​of output variables corresponding to each of the input variable values. Furthermore, the map operation may be a process in which, when the value of an input variable matches one of the input variable values ​​in the map data, the value of the corresponding output variable in the map data is the operation result. Furthermore, the map operation may be a process in which, when the value of an input variable does not match any of the input variable values ​​in the map data, the operation result is a value obtained by interpolating the values ​​of multiple output variables included in the map data. Alternatively, the map operation may be a process in which, when the value of an input variable does not match any of the input variable values ​​in the map data, the operation result is the value of the output variable in the map data that corresponds to the closest value of the multiple input variables included in the map data.

[0030] Returning to FIG. 3, the PU 52 acquires the target virtual steering angle α2* input to the user interface 80 (S18). The target virtual steering angle α2* is a target value of the virtual steering angle α2. The target virtual steering angle α2* is a variable indicating the driver's instruction regarding the steering of the trailer 30. The processing of S18 corresponds to the instruction reception processing.

[0031] Next, PU 52 calculates target steering angle α1* as a manipulated variable for feedback control in which virtual steering angle α2 is the controlled variable and target virtual steering angle α2* is the controlled variable target value (S20). Here, feedback control may be, for example, processing in which the output value of a proportional element, to which the difference between target virtual steering angle α2* and virtual steering angle α2 is input, is the target steering angle α1*. Alternatively, feedback control may be processing in which the sum of the output value of a proportional element and the output value of an integral element, to which a value corresponding to the difference between target virtual steering angle α2* and virtual steering angle α2 is input, is the target steering angle α1*. Alternatively, feedback control may be processing in which the sum of the output value of a proportional element and the output value of a derivative element, to which a value corresponding to the difference between target virtual steering angle α2* and virtual steering angle α2 is input, is the target steering angle α1*. For example, the feedback control may be a process in which the sum of the output value of a proportional element, the output value of a differential element, and the output value of an integral element, whose input is a value corresponding to the difference between the target virtual steering angle α2* and the virtual steering angle α2, is the target steering angle α1*.

[0032] Next, the PU 52 determines whether the magnitude of the target steering angle α1* is greater than an upper limit value α1th (S22). The upper limit value α1th is the maximum allowable control value for the magnitude of the steering angle α1. If the PU 52 determines that the magnitude of the target steering angle α1* is greater than the upper limit value α1th (S22: YES), the PU 52 executes guard processing to set the magnitude of the target steering angle α1* to the upper limit value α1th (S24). If the PU 52 completes the processing of S24 or if the determination in the processing of S22 is negative, the PU 52 outputs the target steering angle α1* as a command signal to the steering system 60 (S26). That is, the PU 52 operates the steering system 60. The processing of S20 to S26 corresponds to the steering angle control processing.

[0033] The PU 52 temporarily terminates the series of processes shown in FIG. 3 when the process of S26 is completed or when a negative determination is made in the process of S10. "Jackknife Countermeasures" The procedure for the countermeasure against jackknife in the reverse assist mode is shown in Figure 5. The process shown in Figure 5 is realized by the PU 52 repeatedly executing the reverse assist program 54a, for example, at predetermined intervals.

[0034] In the series of processes shown in Fig. 5, the PU 52 first determines whether the reverse assist mode is selected (S30). If the PU 52 determines that the reverse assist mode is selected (S30: YES), the PU 52 acquires the target steering angle α1* (S32). The process of S32 corresponds to the acquisition process. Next, the PU 52 determines whether the following condition (A) is satisfied (S34).

[0035] Condition (A): The condition is that the magnitude of the target steering angle α1* is equal to or greater than the upper limit value α1th. When the PU 52 determines that the condition (A) is satisfied (S34: YES), the PU 52 acquires the hitch angle β (S36). The process of S36 corresponds to the acquisition process. Then, the PU 52 determines whether the following condition (B) is satisfied (S38).

[0036] Condition (B): The product of the target steering angle α1* and the hitch angle β is negative. The process of S38 is a process for determining whether the steering angle α1 and the hitch angle β have opposite signs, that is, whether one of the conditions for when a jackknife phenomenon occurs is met.

[0037] Figures 6A and 6B show cases where the jackknife phenomenon occurs. More specifically, Figure 6A shows a case where the steering angle α1 is an angle on the left turning side. In this case, the jackknife phenomenon occurs when the hitch angle β is a value on the right turning side. On the other hand, Figure 6B shows a case where the steering angle α1 is an angle on the right turning side. In this case, the jackknife phenomenon occurs when the hitch angle β is a value on the left turning side.

[0038] It should be noted that the steering angle α1 and the hitch angle β may be defined as positive when they rotate counterclockwise about the center of rotation, for example. Returning to FIG. 5, when it is determined that the condition (B) is met (S38: YES), the PU 52 determines whether or not the following condition (C) is met (S40).

[0039] Condition (C): The rate of increase in the magnitude of the hitch angle β is equal to or greater than zero. FIG. 5 shows an example in which the rate of increase in the magnitude of the hitch angle β is defined by the value obtained by subtracting the magnitude of the previous value “β(n-1)” from the magnitude of the current value “β(n)” of the hitch angle β.

[0040] Figure 7 shows the hitch angle β and the rate of change of the hitch angle β when the jackknife phenomenon occurs. The curve f1 in Figure 7 shows the case where the steering angle α1 is "+α1th." The curve f2 shows the case where the steering angle α1 is "-α1th." The curve f3 shows the case where the steering angle α1 is "0."

[0041] Jackknife occurs when the magnitude of the hitch angle β cannot be reduced by adjusting the steering angle α1. On curve f1, jackknife occurs when the hitch angle β is negative and the rate of change of the hitch angle β is equal to or less than zero. Therefore, as shown by dots in Figure 7, point P1 or the region where the rate of change of the hitch angle β is negative is the region where jackknife occurs. On curve f2, jackknife occurs when the hitch angle β is positive and the rate of change of the hitch angle β is equal to or greater than zero. Therefore, as shown by dots in Figure 7, point P2 or the region where the rate of change of the hitch angle β is positive is the region where jackknife occurs. The processes of S34, S38, and S40 correspond to the determination process.

[0042] Returning to FIG. 5, when the PU 52 determines that the condition (C) is satisfied (S40: YES), it determines that a jackknife phenomenon has occurred (S42). That is, when the PU 52 determines that the logical product of the conditions (A), (B), and (C) is true, it determines that a jackknife phenomenon has occurred. Then, the PU 52 stops the reverse assist mode (S46). That is, the PU 52 stops the processing shown in FIG. 3. In other words, the PU 52 stops the processing of manipulating the steering angle α1 in accordance with the target virtual steering angle α2*.

[0043] In addition, the PU 52 executes a warning process to notify the user that a jackknife phenomenon has occurred (S48). For example, the user interface 80 may be provided with a display device, and the process of S48 may be a process of causing the PU 52 to display visual information indicating that a jackknife phenomenon has occurred on the display device. For example, the user interface 80 may be provided with a speaker, and the process of S48 may be a process of causing the PU 52 to output audio information indicating that a jackknife phenomenon has occurred from the speaker. For example, if the device of the user interface 80 for inputting the target virtual steering angle α2* is an operation unit that involves physical displacement, the process of S48 may be a process of causing the PU 52 to vibrate the operation unit. For example, the process of S48 may be a process of causing the PU 52 to vibrate the steering wheel that operates the steering angle α1.

[0044] The PU 52 also decelerates the combination vehicle 10 (S50). In the reverse assist mode, when the PU 52 controls the vehicle speed by operating the drive system 62 and the braking system 64, the process of S50 may be a process in which the PU 52 reduces the target vehicle speed. In the reverse assist mode, when the vehicle speed is left to the user's accelerator operation, the process of S50 may be a process in which the PU 52 sets an upper limit for the vehicle speed. Here, the upper limit may be a value lower than the normal vehicle speed expected in the reverse assist mode. In the reverse assist mode, when the vehicle speed is left to the user's accelerator operation, the process of S50 may be a process in which the PU 52 forcibly intervenes in the vehicle speed control to reduce the target value. Note that the processes of S46 to S50 correspond to the countermeasure process.

[0045] The PU 52 temporarily terminates the series of processes shown in FIG. 5 when the process of S50 is completed or when a negative determination is made in the processes of S30, S34, S38, and S40. "Actions and Effects of the Present Embodiment" The PU 52 determines that a jackknife event has occurred if it determines that the logical product of conditions (A), (B), and (C) is true. Conditions (A), (B), and (C) are conditions that specify the state when a jackknife event occurs, independent of the model of the combination vehicle 10. Therefore, it is possible to determine with high accuracy that a jackknife event has occurred, regardless of the type of trailer 30 coupled to the tractor 20.

[0046] According to the present embodiment described above, the following actions and effects can be further obtained. (1-1) Because the PU 52 executes the process of S48, the user can be sure that the jackknife phenomenon has occurred. Therefore, the user can eliminate the jackknife phenomenon by stopping the articulated vehicle 10 and then moving it forward.

[0047] (1-2) Because the PU 52 executes the process of S50, it is possible to prolong as much as possible the time until the hitch angle β becomes excessively large due to the jackknife phenomenon, which allows the user to resolve the jackknife phenomenon before the hitch angle β becomes excessively large due to the jackknife phenomenon.

[0048] <Second embodiment> The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment.

[0049] Figure 8 shows the procedure for processing related to jackknife countermeasures in the reverse assist mode according to this embodiment. The processing shown in Figure 8 is realized by the PU 52 repeatedly executing the reverse assist program 54a, for example, at a predetermined interval. For convenience, the same step numbers are assigned to processes in Figure 8 that correspond to those shown in Figure 5.

[0050] In the series of processes shown in FIG. 8, instead of the process of S40, the PU 52 determines whether the following condition (D) is met (S40a). Condition (D): The rate of increase in the magnitude of the hitch angle β is equal to or greater than a specified value Δth, where the specified value Δth is set to a value smaller than zero.

[0051] If the rate of increase in the magnitude of the hitch angle β is less than zero, the hitch angle β has not yet become uncontrollable. However, if the rate of decrease in the magnitude of the hitch angle β is excessively slow when conditions (A) and (B) are met, it is considered that the situation is prone to jackknife occurrence. Note that the processes of S34, S38, and S40a correspond to the determination process.

[0052] When the PU 52 determines that the logical product of the conditions (A), (B), and (D) is true (S40a: YES), the PU 52 determines that there is a high risk of the jackknife phenomenon occurring (S42a). Then, the PU 52 executes a process to notify that there is a high risk of the jackknife phenomenon occurring (S48a). The process of S48a corresponds to a countermeasure process.

[0053] When the PU 52 completes the process of S48a, it temporarily ends the series of processes shown in FIG. <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0054] "About the judgment process" In the process of S34, it may be determined whether the magnitude of the steering angle α1 is equal to or greater than the upper limit value α1th.

[0055] In the process of S38, it may be determined whether the steering angle α1 and the hitch angle β have opposite signs. The value defining the maximum value of the steering angle α1 is not limited to the upper limit value α1th of the target steering angle α1*. For example, it may be a mechanically determined maximum value.

[0056] The condition that "the magnitude of the steering angle is equal to or greater than a predetermined value" does not necessarily have to be a condition that the magnitude of the steering angle is equal to or greater than a value that defines the maximum value of the steering angle α1. For example, the value may be a predetermined amount smaller than the value that defines the maximum value. Even in this case, if the logical product of condition (B) and condition (C) is true, it is possible to determine that the risk of jackknife occurrence has increased. Here, condition (C) may be replaced with condition (D).

[0057] "About handling" 5 shows an example in which all three processes, S46, S48, and S50, are executed, but this is not limiting. For example, any two of the three processes may be executed. Also, for example, only one of the three processes may be executed.

[0058] 8, a process for manipulating the steering angle α1 so as to reduce the absolute value of the hitch angle β may be added as a countermeasure process. This means that the process for manipulating the steering angle α1 so as to reduce the absolute value of the hitch angle β takes priority over the instruction of the target virtual steering angle α2*.

[0059] "Regarding steering angle control processing" The target steering angle α1* is not limited to being a manipulated variable of feedback control in which the virtual steering angle α2 is the controlled variable and the target virtual steering angle α2* is the target value of the controlled variable. For example, the target steering angle α1* may be a manipulated variable of open-loop control in which the virtual steering angle α2 is the controlled variable.

[0060] The control variable of the steering angle control process does not necessarily have to be the virtual steering angle α2. For example, the control variable of the steering angle control process may be the trajectory of trailer 30. In that case, for example, the target steering angle α1* may be a manipulated variable of feedback control in which the trajectory of trailer 30 is the control variable and the target value of the trajectory is the target value of the control variable. Also, for example, the target steering angle α1* may be a manipulated variable of open-loop control in which the trajectory of trailer 30 is the control variable. Also, for example, the control variable of the steering angle control process may be hitch angle β. In that case, for example, the target steering angle α1* may be a manipulated variable of feedback control in which the hitch angle β is the control variable and the target hitch angle β* is the target value of the control variable. Also, for example, the target steering angle α1* may be a manipulated variable of open-loop control in which the hitch angle β is the control variable.

[0061] "About the control device" The control device is not limited to one equipped with a PU 52 and a storage device 54 and executing software processing. For example, it may be equipped with a dedicated hardware circuit, such as an ASIC, that executes at least part of the processing executed in the above embodiment. That is, the control device may be equipped with a processing circuit having any of the following configurations (a) to (c): (a) A processing circuit equipped with a processing device that executes all of the above processing in accordance with a program and a program storage device, such as a storage device, that stores the program. (b) A processing circuit equipped with a processing device and program storage device that executes part of the above processing in accordance with a program, and a dedicated hardware circuit that executes the remaining processing. (c) A processing circuit equipped with a dedicated hardware circuit that executes all of the above processing. Here, there may be multiple software execution devices equipped with a processing device and a program storage device, and multiple dedicated hardware circuits.

[0062] "About Computers" The computer is not limited to the PU 52 mounted on the vehicle. For example, the processes of S46 to S50 shown in Fig. 5 may be executed by the PU 52, and the processes of S30 to S42 may be executed by a mobile terminal of the user.

[0063] "About the vehicle" The articulated vehicles are not limited to the vehicles shown in FIG.

Claims

1. A jackknife prevention device for a combination vehicle in which a tractor and a trailer are coupled, configured to execute an acquisition process, a determination process, and a handling process; The acquisition process is a process of acquiring a value of a steering angle variable and a value of a hitch angle variable, the steering angle variable is a variable indicating the steering angle of the steered wheels of the combination vehicle, the hitch angle variable is a variable indicating an angle between the front-rear direction of the tractor and the front-rear direction of the trailer, the determination process is a process for determining whether a logical product of the following conditions is true: the magnitude of the value of the steering angle variable is equal to or greater than a predetermined value; the value of the steering angle variable is a value indicating either a right turn or a left turn and the value of the hitch angle variable is a value indicating the other of the right turn or the left turn; and the rate of increase in the magnitude of the value of the hitch angle variable is equal to or greater than a threshold value; The countermeasure process is a process for countering a jackknife phenomenon that is executed when the logical product is determined to be true while the combination vehicle is traveling backward.

2. 2. An anti-jackknife device for an articulated vehicle according to claim 1, wherein the predetermined value defines a maximum value of the magnitude of the steering angle.

3. The anti-jackknife device for articulated vehicles according to claim 1 , wherein the threshold value is zero.

4. The anti-jackknife device for articulated vehicles according to claim 1 , wherein the threshold value is less than zero.

5. 2. The device for preventing a jackknife collision for a combination vehicle according to claim 1, wherein the countermeasure processing is a processing for decelerating the combination vehicle.

6. 4. The device for preventing jackknife damage to an articulated vehicle according to claim 3, wherein the countermeasure processing is processing for notifying a user that a jackknife has occurred.

7. 5. The device for preventing jackknife damage to an articulated vehicle according to claim 4, wherein the countermeasure processing is processing for notifying a user that there is a high possibility of the vehicle falling into a jackknife state.

8. The control unit is configured to execute an instruction reception process and a steering angle control process, the instruction receiving process is a process of receiving an instruction regarding steering of the trailer, the steering angle control process is a process of manipulating the steering angle in accordance with the instruction, 2. The device for preventing a jackknife from occurring in an articulated vehicle according to claim 1, wherein the countermeasure processing is processing for stopping the steering angle control processing.

9. A method for preventing jackknife damage to a combination vehicle in which a tractor and a trailer are coupled, comprising: The method includes executing an acquisition process, executing a determination process, and executing a response process; The acquisition process is a process of acquiring a value of a steering angle variable and a value of a hitch angle variable, the steering angle variable is a variable indicating the steering angle of the steered wheels of the combination vehicle, the hitch angle variable is a variable indicating an angle between the front-rear direction of the tractor and the front-rear direction of the trailer, the determination process is a process for determining whether a logical product of the following conditions is true: the magnitude of the value of the steering angle variable is equal to or greater than a predetermined value; the value of the steering angle variable is a value indicating either a right turn or a left turn and the value of the hitch angle variable is a value indicating the other of the right turn or the left turn; and the rate of increase in the magnitude of the value of the hitch angle variable is equal to or greater than a threshold value; The countermeasure process is a method for countering a jackknife phenomenon for an articulated vehicle, and is executed when the logical product is determined to be true while the articulated vehicle is traveling backward, as a countermeasure against the jackknife phenomenon.

10. A program for preventing jackknife damage to a combination vehicle in which a tractor and a trailer are coupled, The computer has instructions to execute an acquisition process, a determination process, and a handling process, The acquisition process is a process of acquiring a value of a steering angle variable and a value of a hitch angle variable, the steering angle variable is a variable indicating the steering angle of the steered wheels of the combination vehicle, the hitch angle variable is a variable indicating an angle between the front-rear direction of the tractor and the front-rear direction of the trailer, the determination process is a process for determining whether a logical product of the following conditions is true: the magnitude of the value of the steering angle variable is equal to or greater than a predetermined value; the value of the steering angle variable is a value indicating either a right turn or a left turn and the value of the hitch angle variable is a value indicating the other of the right turn or the left turn; and the rate of increase in the magnitude of the value of the hitch angle variable is equal to or greater than a threshold value; The countermeasure process is a program for countering a jackknife phenomenon for an articulated vehicle, and is executed when the logical product is determined to be true while the articulated vehicle is traveling backward.

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