Calculation device for combined vehicles, control device for combined vehicles, calculation method for combined vehicles, and calculation program for combined vehicles

Abstract

This coupled vehicle is provided with a tractor and a trailer which is towed by the tractor. A coupled vehicle calculation device (50) is configured so as to execute curvature variable acquisition processing, trailer length variable acquisition processing and virtual steering angle calculation processing. The curvature variable acquisition processing involves acquiring a curvature variable value. The curvature variable expresses the curvature of the travel path of the trailer. The trailer length variable acquisition processing involves acquiring a trailer length variable value. The trailer length variable expresses the length of the trailer. The virtual steering angle calculation processing involves calculating a virtual steering angle α2, with the curvature variable value and the trailer length variable value as inputs. The virtual steering angle α2 expresses the direction of displacement at the coupling site between the trailer and the tractor.

Description

[Technical Field]

[0001] The present disclosure relates to a calculation device for a combination vehicle, a control device for a combination vehicle, a calculation method for a combination vehicle, and a calculation program for a combination vehicle. [Background technology]

[0002] For example, Patent Document 1 below describes a control device that performs trailer backing assist control. This control device estimates a hitch angle using the trailer yaw rate and the tractor yaw rate. The estimated hitch angle is then used to perform backing assist control. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 9,340,228 Summary of the Invention [Problem to be solved by the invention]

[0004] The control device uses the yaw rate of the tractor to calculate the variables used for trailer travel control. However, if the trailer is displaced while the tractor is stopped due to, for example, a curb, the yaw rate of the tractor may not be an appropriate value to use for calculating the variables used for trailer travel control. [Means for solving the problem]

[0005] One aspect of the present disclosure provides a calculation device for an articulated vehicle. The articulated vehicle includes a tractor and a trailer towed by the tractor. The calculation device for the articulated vehicle is configured to execute a curvature variable acquisition process, a trailer length variable acquisition process, and a virtual steering angle calculation process. The curvature variable acquisition process is a process for acquiring a value of a curvature variable. The curvature variable is a variable indicating the curvature of the traveling trajectory of the trailer. The trailer length variable acquisition process is a process for acquiring a value of a trailer length variable. The trailer length variable is a variable indicating the length of the trailer. The virtual steering angle calculation process is a process for calculating a virtual steering angle using the value of the curvature variable and the value of the trailer length variable as inputs. The virtual steering angle is an angle indicating the direction of displacement of the connection point between the trailer and the tractor.

[0006] Another aspect of the present disclosure provides a method for controlling an articulated vehicle. The articulated vehicle includes a tractor and a trailer towed by the tractor. The method for controlling the articulated vehicle is a method of executing a curvature variable acquisition process, a trailer length variable acquisition process, and a virtual steering angle calculation process. The curvature variable acquisition process is a process for acquiring a value of a curvature variable. The curvature variable is a variable that indicates the curvature of the traveling trajectory of the trailer. The trailer length variable acquisition process is a process for acquiring a value of a trailer length variable. The trailer length variable is a variable that indicates the length of the trailer. The virtual steering angle calculation process is a process for calculating a virtual steering angle using the value of the curvature variable and the value of the trailer length variable as inputs. The virtual steering angle is an angle that indicates the direction of displacement of the connection point between the trailer and the tractor.

[0007] Another aspect of the present disclosure provides a control program for an articulated vehicle. The articulated vehicle includes a tractor and a trailer towed by the tractor. The control program for the articulated vehicle causes a computer to execute a curvature variable acquisition process, a trailer length variable acquisition process, and a virtual steering angle calculation process. The curvature variable acquisition process is a process for acquiring a value of a curvature variable. The curvature variable is a variable that indicates the curvature of the traveling trajectory of the trailer. The trailer length variable acquisition process is a process for acquiring a value of a trailer length variable. The trailer length variable is a variable that indicates the length of the trailer. The virtual steering angle calculation process is a process for calculating a virtual steering angle using the value of the curvature variable and the value of the trailer length variable as inputs. The virtual steering angle is an angle that indicates the direction of displacement of the connection point between the trailer and the tractor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing the configuration of an articulated vehicle according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a control system according to the embodiment. [Figure 3] 3 is a flowchart showing a procedure of a process executed by a control device according to the embodiment. [Figure 4] 3 is a flowchart showing a procedure of a process executed by a control device according to the embodiment. [Figure 5] 3 is a flowchart showing a procedure of a process executed by a control device according to the embodiment. [Figure 6] 6A and 6B are diagrams showing the effects of this embodiment. [Figure 7] 10 is a flowchart showing a procedure of a process executed by a control device according to a second embodiment. [Figure 8] 10 is a flowchart showing a procedure of a process executed by a control device according to a third embodiment. [Figure 9] FIG. 2 is a diagram showing a model used to calculate a hitch angle in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment The first embodiment will be described below with reference to the drawings. "Configuration of articulated vehicles" As shown in FIG. 1, the articulated vehicle 10 has a tractor 20 and a trailer 30. FIG. 1 shows an example of the tractor 20 as a pickup truck, which is a type of small freight vehicle. 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. FIG. 1 also shows an example of the trailer 30 as a box-shaped trailer. 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 combination vehicle 10. As shown in Figure 2, the combination vehicle 10 is equipped with a control device 50. More specifically, the tractor 20 is equipped with the control device 50. The control device 50 operates a steering system 60 of the tractor 20, a drive system 62 of the tractor 20, and a braking system 64 of the tractor 20 to control the control variables of the combination vehicle 10 as the control object. 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 of tractor 20. The steered wheels are, for example, front wheels 22 shown in FIG. 1. Note that steering system 60 may also include a steering control device that operates the steering actuator. In this case, "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] Braking system 6 2 The braking system 6 includes at least one of a device that slows down the rotation of the wheels of the tractor 20 by frictional force, and a device that slows down the rotation of the wheels of the tractor 20 by converting the power of the wheels into electrical energy. The device that slows down the rotation of the wheels of the tractor 20 by converting into electrical energy may be shared with the rotating electric machine of the drive system. 2 The braking control system 62 may include a braking control device that controls a device that slows down the rotation of the wheels. In this case, "the control device 50 operates the braking system 62" means that the control device 50 outputs a command signal to the braking control device.

[0015] To control the control variables, the control device 50 references the steering angle α1 of the steered wheels of the tractor 20, which is detected by the steering angle sensor 70. The steering angle α1 is a value whose sign is positive for either a right turn or a left turn, and whose sign is negative for the other. The steering angle α1 is the turning angle of the tires. The control device 50 also references the yaw rate yr of the trailer 30, which is detected by the yaw rate sensor 72. When the user selects an appropriate trailer 30 to be coupled to the tractor 20 from among multiple trailers 30, the user connects the yaw rate sensor 72 of the selected trailer 30 to the electronic components of the tractor 20. The control device 50 also references the wheel speeds ωwr and ωwl of the trailer 30, which are detected by the wheel speed sensor 74. The wheel speeds ωwr and ωwl are the rotational speeds of the right and left wheels 32, respectively. In addition, when the user appropriately selects and adopts a trailer 30 to be connected to the tractor 20 from among a plurality of trailers 30, the wheel speed sensor 74 provided on the adopted trailer 30 is connected to the electronic components of the tractor 20.

[0016] The control device 50 sets the control amount according to the operation state of the user interface 80. The user interface 80 has a function of transmitting the user's intention to the control device 50, such as selecting either manual steering or automatic steering of the combination vehicle 10.

[0017] 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, a TPU, etc. The storage device 54 stores a reverse assist program 54a.

[0018] The reverse assist program 54a defines commands for executing reverse assist processing. The reverse assist processing is processing that should be executed by the PU 52 to assist in the reverse of the combination vehicle 10. The reverse assist processing is processing that automatically steers the tractor 20. However, in the reverse assist processing, braking and accelerator operation are left to the driver. The reverse assist processing also includes processing for receiving a request to steer the trailer 30. The reverse assist processing then controls the steering angle of the tractor 20 so as to satisfy the steering request of the trailer 30.

[0019] Here, a steering request for the trailer 30 is input by the driver via the user interface 80. The steering request is communicated by specifying a virtual steering angle α2 for the trailer 30. The virtual steering angle α2 is an angle that indicates the displacement direction of the trailer 30 at the connection point between the trailer 30 and the tractor 20. In other words, the virtual steering angle α2 is an angle that indicates the displacement direction of the shaft 42. The virtual steering angle α2 may be specified, for example, by providing the user interface 80 with a dial that has a positive correlation with the virtual steering angle α2. Here, it is not essential that the rotation angle of the dial and the virtual steering angle α2 are proportional to each other. Note that hereinafter, the virtual steering angle α2 specified by the driver will be referred to as the target virtual steering angle α2*.

[0020] The reverse assist process is executed using a virtual steering angle α2 estimated from the detection values ​​of the sensors. The following describes various pre-processing steps for estimating the virtual steering angle α2, followed by the reverse assist process.

[0021] "Get trailer length" FIG. 3 shows the procedure for the process of acquiring the trailer length Lt. The trailer length Lt is the length of the line connecting the center of a line segment connecting the rotation centers of the two wheels 32 and the axle 42. The series of processes shown in FIG. 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 number of each process is represented by a number preceded by "S."

[0022] In the series of processes shown in Fig. 3, the PU 52 first determines whether or not the trailer length Lt has been acquired (S10). For example, the PU 52 may determine that the trailer length Lt has been acquired if the trailer length Lt is stored in a predetermined storage area of ​​the storage device 54. However, when the trailer 30 coupled to the tractor 20 is changed, it is desirable that the user notify this by operating the user interface 80. In that case, if the trailer length Lt is stored in the predetermined storage area, the PU 52 may temporarily erase the trailer length Lt.

[0023] If the PU 52 determines that the trailer length Lt has not yet been acquired (S10: NO), it displays visual information prompting the user to input the trailer length Lt by operating the display device 82 (S12). Then, the PU 52 waits until the trailer length Lt is input by operating the user interface 80 (S14: NO). If the PU 52 determines that the trailer length Lt has been input (S14: YES), it stores the trailer length Lt in a predetermined storage area of ​​the storage device 54 (S16).

[0024] The PU 52 temporarily ends the series of processes shown in FIG. 3 when an affirmative determination is made in the process of S10 or when the process of S16 is completed. "Calculation of virtual steering angle α2" The procedure for the process of calculating the virtual steering angle α2 is shown in Fig. 4. The series of processes shown in Fig. 4 is realized by the PU 52 repeatedly executing the reverse assist program 54a, for example, at predetermined intervals.

[0025] In the series of processes shown in FIG. 4, the PU 52 first acquires the yaw rate yr of the trailer 30 and the vehicle speed V of the trailer 30 (S20). The vehicle speed V of the trailer 30 is calculated by the PU 52 according to at least one of the wheel speeds ωwr and ωwl. The vehicle speed V may be, for example, the average value of the wheel speeds ωwr and ωwl. Next, the PU 52 assigns a value obtained by dividing the yaw rate yr by the vehicle speed V to the curvature ktr (S22). Then, the PU 52 reads out the trailer length Lt stored in the predetermined storage area (S24). Then, the PU 52 assigns a value obtained by multiplying the value of the dependent variable of an arctangent function, which has the product of the trailer length Lt and the curvature ktr as the independent variable, by "-1" to the virtual steering angle α2 (S26).

[0026] In addition, PU5 2 When the process of S26 is completed, the series of processes shown in FIG. 4 is temporarily ended. "Reverse assist processing" The procedure of the reverse assist process is shown in Figure 5. The series of processes shown in Figure 5 is realized by the PU 52 repeatedly executing the reverse assist program 54a, for example, at predetermined intervals.

[0027] In the series of processes shown in Fig. 5, the PU 52 first determines whether the vehicle is in the reverse assist mode (S30). If the PU 52 determines that the vehicle is in the reverse assist mode (S30: YES), the PU 52 acquires the target virtual steering angle α2* (S32). Then, the PU 52 substitutes the manipulated variable of the control in which the virtual steering angle α2 calculated by the process of Fig. 4 is the control variable and the target virtual steering angle α2* is the target value of the control variable, for the target steering angle α1* (S34). This manipulated variable may be the manipulated variable of the feedback control. Also, for example, this manipulated variable may be the sum of the manipulated variable of the feedback control and the manipulated variable of the open-loop control.

[0028] Next, PU 52 acquires steering angle α1 (S36). Then, PU 52 calculates a control manipulated variable in which steering angle α1 is a control variable and target steering angle α1* is a target value of the control variable (S38). This manipulated variable may be a feedback control manipulated variable. Also, for example, this manipulated variable may be the sum of a feedback control manipulated variable and an open-loop control manipulated variable. This manipulated variable may be, for example, the torque of the motor of steering system 60.

[0029] Then, the PU 52 operates the steering system 60 in accordance with the amount of operation (S40). The PU 52 temporarily terminates the series of processes shown in FIG. 5 when the process of S40 is completed or when a negative determination is made in the process of S30.

[0030] "Actions and Effects of the Present Embodiment" The PU 52 calculates a curvature ktr of the traveling trajectory of the trailer 30 based on the yaw rate yr of the trailer 30 and the vehicle speed V of the trailer 30 as input variables. The PU 52 calculates a virtual steering angle α2 based on the curvature ktr of the traveling trajectory of the trailer 30 as input. The PU 52 controls the virtual steering angle α2 so that it approaches the target virtual steering angle α2*.

[0031] In this way, in this embodiment, traveling control of the trailer 30 can be performed without using the detected value of the yaw rate of the tractor 20. When the detected value of the yaw rate of the tractor 20 is not used, for example, even when the tractor 20 is stopped and only the trailer 30 is displaced, the virtual steering angle α2 can be calculated with high accuracy. Then, by using the virtual steering angle α2 as the manipulated variable for feedback control, traveling of the trailer 30 can be controlled with high accuracy.

[0032] According to the present embodiment described above, the following actions and effects can be further obtained. (1-1) The virtual steering angle α2 is calculated using the actual curvature ktr obtained by traveling the trailer 30. This allows the virtual steering angle α2 to be calculated with higher accuracy than when the virtual steering angle α2 is calculated using a model equation of the articulated vehicle 10.

[0033] 6A and 6B show, with solid lines, the travel control of the trailer 30 using the virtual steering angle α2 according to this embodiment. Also, with dashed lines, each of FIGS. 6A and 6B shows, with dashed lines, a comparative example of the travel control of the trailer 30 using the virtual steering angle α2 calculated using the model equation.

[0034] In detail, Fig. 6A shows the travel trajectory of the trailer 30. In Fig. 6A, the vertical axis is the y-axis of a plane coordinate system, and the horizontal axis is the x-axis of the plane coordinate system. As shown in Fig. 6A, a difference occurs in the curvature of the trailer 30 due to travel between the present embodiment and the comparative example. This is because, in the case of a model formula, model errors occur. In contrast, in the case of the present embodiment, the virtual steering angle α2 calculated according to the actual curvature of the trailer 30 is used as the control amount, so the trajectory of the trailer 30 can be controlled with high precision.

[0035] Figure 6B shows the transition of the hitch angle. As shown in Figure 6B, a steady deviation occurs in the transition of the hitch angle between this embodiment and the comparative example. This difference is due to a model error in the comparative example. (1-2) If the trailer length Lt has not been acquired, the PU 52 prompts the user to input the trailer length Lt. This makes it possible to acquire the trailer length Lt.

[0036] <Second embodiment> The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment.

[0037] 7 shows the procedure for the process of calculating the virtual steering angle α2 according to this embodiment. The series of processes shown in FIG. 7 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 used in FIG. 7 to designate processes corresponding to those shown in FIG. 4.

[0038] 7, the PU 52 first acquires the wheel speeds ωwr and ωwl (S20a). Next, the PU 52 subtracts the wheel speed ωwr from the wheel speed ωwl, divides the result by the tread width d, and assigns the result to the curvature ktr (S22a). The tread width d is the distance between the rotation centers of the two wheels 32 of the trailer 30.

[0039] Then, the PU 52 executes the processes of S24 and S26, and temporarily ends the series of processes shown in FIG. <Third embodiment> The third embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment.

[0040] In this embodiment, when the possibility of a jackknife occurring increases, a process is executed to issue a warning to that effect. A jackknife is a phenomenon in which the trailer 30 cannot be steered due to an excessively large hitch angle.

[0041] The procedure for the process related to the warning is shown in Fig. 8. The series of processes shown in Fig. 8 is realized by the PU 52 repeatedly executing the reverse assist program 54a, for example, at predetermined intervals.

[0042] In the series of processes shown in Fig. 8, the PU 52 first determines whether the vehicle is in the reverse assist mode (S50). If the PU 52 determines that the vehicle is in the reverse assist mode (S50: YES), the PU 52 acquires the steering angle α1 and the virtual steering angle α2 (S52). Then, the PU 52 calculates the hitch angle β using the following equation (c1) (S54).

[0043] β=-α2-arctan{(h1 / l1)·tan(α1)} …(c1) The above equation (c1) is based on a model of the tractor 20 and the trailer 30. FIG. 9 illustrates the model. In the model illustrated in FIG. 9, the pair of front wheels 22 of the tractor 20 correspond to the front wheels C0, and the pair of rear wheels 24 of the tractor 20 correspond to the rear wheels B1. That is, a two-wheel model is employed for the tractor 20. The pair of wheels 32 of the trailer 30 correspond to the wheels B2. The angle between the line defined by the front wheels C0 and the hitch point C1 and the line defined by the hitch point C1 and the wheels B2 is the hitch angle β. The hitch point C1 corresponds to the axis 42 in FIG. 1. The front wheel speed VC0, which is the speed of the front wheels C0, is a vector quantity that advances 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 wheels C0 and the line defined by the front wheels C0 and the hitch point C1. The direction of the vehicle speed Vtra of the tractor 20 is parallel to the line defined by the front wheels C0 and the hitch point C1. In addition, the direction of the vehicle speed Vtra and 9 The angle formed by the x-axis is angle θ1. Distance l1 is the length between the front wheel C0 and the rear wheel B1. Distance h1 is the length between the rear wheel B1 and the hitch point C1.

[0044] In FIG. 9, the distance from the hitch point C1 to the center of rotation of the wheel B2 is indicated as the trailer length Lt. In this embodiment, the direction of the speed VC1 of the hitch point C1 relative to the direction of travel from the wheel B2 to the hitch point C1 is the virtual steering angle α2. Therefore, when the angle γ1 formed by the direction of the speed VC1 of the hitch point C1 relative to the direction of travel from the hitch point C1 to the front wheel C0 is used, the virtual steering angle α2 is "-(β-γ1)."

[0045] In the model shown in FIG. 9, the following equations (c2) to (c4) 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.

[0046] VC0·cosα1=VB1 …(c2) xc0=xb1+l1·cosθ1 …(c3) xc1=xb1-h1·cosθ1 …(c4) By differentiating both sides of the above equations (c3) and (c4) and using equation (c2), we obtain the following equation (c5).

[0047] h1·tanα1+l1·tanγ1=0 …(c5) According to the above formula (c5), the angle γ1 can be expressed by the steering angle α1. Therefore, the hitch angle β is expressed by the above formula (c1).

[0048] 8, the PU 52 acquires the jackknife hitch angle βth (S56). In this embodiment, the jackknife hitch angle βth is a fixed value determined according to the maximum value of the steering angle α1.

[0049] That is, according to the model shown in FIG. 9, the first-order time differential value of the hitch angle β is expressed by the following equation (c6). dβ / dt =-(Vtra / l2)·sinβ -{Vtra / (l1·l2)}·(l2+h1·cosβ)·tanα …(c6) If a jackknife hitch occurs, the hitch angle β cannot be changed even if the steering angle α1 is changed to its maximum value α1th. Therefore, the hitch angle β obtained by setting the time differential value of the hitch angle β in the above equation (c6) to zero and substituting the maximum value α1th for the steering angle α1 is regarded as the jackknife hitch angle βth. However, because the steering angle α1 can take both positive and negative values, both "α1th" and "(-1)·αth" can be substituted into the above equation (c6). Therefore, the jackknife hitch angle βth actually takes two values. These two jackknife hitch angles βth are pre-stored in the storage device 54. In the processing of S56, the PU 52 selects one of the two values ​​that results in a smaller absolute difference from the hitch angle β, depending on the sign of the steering angle α1 and the sign of the rate of change of the steering angle α1.

[0050] Next, the PU 52 determines whether the absolute value of the difference between the hitch angle β and the jackknife hitch angle βth is equal to or less than a threshold value Δth (S58). This process is for determining whether the vehicle is in a state where the jackknife phenomenon is likely to occur. If the PU 52 determines that the difference is equal to or less than the threshold value Δth (S58: YES), the PU 52 operates the speaker 84 to warn the driver that the vehicle is in a state where the jackknife phenomenon is likely to occur (S60).

[0051] The PU 52 temporarily terminates the series of processes shown in FIG. 8 when the process of S60 is completed or when a negative determination is made in the processes of S50 and S58. As described above, in this embodiment, a process for suppressing the occurrence of a jackknife phenomenon is executed using the hitch angle β. The hitch angle β, which is input to this process, is calculated without using the detected value of the yaw rate of the tractor 20. Therefore, even when, for example, the tractor 20 is stopped and only the trailer 30 is displaced, the hitch angle β calculated with high accuracy can be used.

[0052] <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0053] "About curvature variables" The curvature variable does not necessarily have to be the curvature ktr. For example, it could be the radius of curvature.

[0054] "About the curvature variable acquisition process" The curvature variable acquisition process is not limited to a process of calculating the curvature ktr based on the yaw rate yr and the vehicle speed V as input. The curvature variable acquisition process may, for example, be a process of calculating the curvature ktr based on the travel trajectory of the trailer 30 as input. Here, the travel trajectory is time-series data of the coordinates of the trailer 30. The process of acquiring the coordinates of the trailer 30 may be a process that uses, for example, a global positioning system. Furthermore, the process of acquiring the coordinates of the trailer 30 may be a process that uses image data of the surroundings of the trailer 30 photographed by a camera and map data.

[0055] "About trailer length variable acquisition process" The trailer length variable acquisition process is not limited to a process of receiving trailer length input from the user. For example, the trailer length variable acquisition process may be a process of measuring the trailer length based on image data of the trailer captured by a camera mounted on the tractor 20 as input.

[0056] "About the trailer length variable" The trailer length variable does not necessarily have to be the trailer length Lt. For example, the trailer length variable may be a label variable indicating either large, medium, or small depending on the magnitude of the trailer length Lt's possible values. In that case, the virtual steering angle calculation process may calculate the virtual steering angle α2 using one trailer length Lt corresponding to each of large, medium, and small.

[0057] "About the virtual steering angle calculation process" The virtual steering angle calculation process does not necessarily include inputting the value of an independent variable into the arctangent function. For example, the virtual steering angle calculation process may be a process in which the PU 52 calculates the virtual steering angle α2 using a map while map data is stored in the storage device 54. Here, the map data is data in which the curvature ktr and the trailer length Lt are input variables and the virtual steering angle α2 is an output variable.

[0058] 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 calculation 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 output variable in the corresponding map data is used as the calculation result. Furthermore, when the value of an input variable does not match any of the input variable values ​​in the map data, the map calculation 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 value of the output variable in the map data that corresponds to the closest value of the input variable values ​​in the map data is used as the calculation result. Alternatively, the map calculation 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 value of the output variable in the map data that corresponds to the closest value of the input variable values ​​in the map data is used as the calculation result.

[0059] "Virtual Steering Angle Control Processing" The virtual steering angle control process is not limited to a process in which the virtual steering angle α2 is the control amount and the target virtual steering angle α2* is the target value of the control amount, and the operation amount of the control is assigned to the target steering angle α1*. For example, the virtual steering angle control process may be a process in which the virtual steering angle α2 is the control amount and the target virtual steering angle α2* is the target value of the control amount, and the operation amount of the control is assigned to the torque command value of the motor of the steering system 60.

[0060] The virtual steering angle control process does not necessarily have to be a process related to control of the trailer 30 moving backward. The virtual steering angle control process may be a process related to control of the trailer 30 moving forward, for example.

[0061] "Hitch angle calculation process" The hitch angle calculation process is not limited to a process that performs a calculation using the above formula (c1). For example, the hitch angle calculation process may be a process in which the PU 52 calculates the hitch angle β from a map in a state in which map data is stored in the storage device 54. Here, the map data is data in which the turning angle α1 and the virtual steering angle α2 are input variables and the hitch angle β is an output variable.

[0062] "About operation processing" The operation processing is not limited to the processing of S60. For example, the operation processing may be processing for operating the steering system 60 as predetermined hardware. This can be realized, for example, by including in the operation processing a process for substituting, for the target steering angle α1*, a control operation amount in which the hitch angle β is a control amount and the target value of the hitch angle β is a target value of the control amount.

[0063] The operation process does not necessarily have to be a process related to control of the trailer 30 moving backward. The operation process may be a process related to control of the trailer 30 moving forward, for example. "About the specified hardware" In the processing of S60, the speaker 84 is exemplified as the predetermined hardware to be operated, but this is not limiting. For example, a warning light may be the predetermined hardware. Also, as described in the section "Regarding Operation Processing," the steering system 60 may be the predetermined hardware.

[0064] "About the control device" The control device is not limited to one that includes a PU 52 and a storage device 54 and executes software processing. The control device may include, for example, a dedicated hardware circuit, such as an ASIC, that executes at least part of the processing executed in the above embodiments. That is, the control device may include any of the following processing circuits (a) to (c): (a) a processing circuit that includes 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 that includes 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 that includes a dedicated hardware circuit that executes all of the above processing. Here, there may be multiple software execution devices that include a processing device and a program storage device, and multiple dedicated hardware circuits.

[0065] "About Computers" The computer is not limited to the PU 52 mounted on the vehicle. For example, the process shown in Fig. 3 may be executed by a user's mobile terminal, and the process shown in Fig. 4 and Fig. 5 may be executed by the PU 52.

[0066] "About the vehicle" The articulated vehicles are not limited to the vehicles shown in FIG. Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0067] The statement "at least one of A and B" in this specification should be understood to mean "A only, or B only, or both A and B."

Claims

1. A calculation device for a combination vehicle that is applied to a combination vehicle including a tractor and a trailer towed by the tractor, configured to execute a curvature variable acquisition process, a trailer length variable acquisition process, and a virtual steering angle calculation process; the curvature variable acquisition process is a process of acquiring a value of a curvature variable, the curvature variable is a variable indicating the curvature of the traveling trajectory of the trailer, the trailer length variable acquisition process is a process of acquiring a value of a trailer length variable, the trailer length variable is a variable indicating the length of the trailer, the virtual steering angle calculation process is a process of calculating a virtual steering angle using the value of the curvature variable and the value of the trailer length variable as inputs, A calculation device for articulated vehicles, wherein the virtual steering angle is an angle indicating the direction of displacement of the connection point between the trailer and the tractor.

2. The steering angle acquisition process and the hitch angle calculation process are configured to be executed. the steering angle acquisition process is a process for acquiring a steering angle of a steered wheel of the tractor, the hitch angle calculation process is a process of calculating a hitch angle using the virtual steering angle and the turning angle as inputs, 2. A calculation device for articulated vehicles according to claim 1, wherein the hitch angle is an angle formed between the longitudinal direction of the tractor and the longitudinal direction of the trailer.

3. The control unit is configured to execute a yaw rate acquisition process and a vehicle speed acquisition process, the yaw rate acquisition process is a process of acquiring a yaw rate of the trailer, the vehicle speed acquisition process is a process of acquiring a vehicle speed of the trailer, 2. The computing device for articulated vehicles according to claim 1, wherein the curvature variable acquisition process acquires the value of the curvature variable by calculating the value of the curvature variable using the yaw rate and the vehicle speed as inputs.

4. The trailer is provided with a yaw rate sensor, 4. The computing device for articulated vehicles according to claim 3, wherein the yaw rate acquisition process acquires the yaw rate detected by the yaw rate sensor.

5. The trailer is provided with wheel speed sensors that detect the speeds of the left and right wheels, 4. A computing device for an articulated vehicle according to claim 3, wherein the yaw rate acquisition process acquires the yaw rate by calculating the yaw rate using detected values ​​of the wheel speeds of the left and right wheels detected by the wheel speed sensors as inputs.

6. The computer is configured to execute the processes executed by the calculation device for an articulated vehicle according to claim 1 and a virtual steering angle control process, A control device for an articulated vehicle, wherein the virtual steering angle control processing is processing for controlling the steering angle of the tractor using a control operation amount in which the virtual steering angle is a control amount and the target virtual steering angle is a target value of the control amount.

7. The combination vehicle is configured to execute the processes and the operation process executed by the calculation device of claim 2, The control device for articulated vehicles, wherein the operation processing is a processing for operating predetermined hardware using the hitch angle as an input.

8. The present invention is applied to a combination vehicle including a tractor and a trailer towed by the tractor, Executing a curvature variable acquisition process, a trailer length variable acquisition process, and a virtual steering angle calculation process, the curvature variable acquisition process is a process of acquiring a value of a curvature variable, the curvature variable is a variable indicating the curvature of the traveling trajectory of the trailer, the trailer length variable acquisition process is a process of acquiring a value of a trailer length variable, the trailer length variable is a variable indicating the length of the trailer, the virtual steering angle calculation process is a process of calculating a virtual steering angle using the value of the curvature variable and the value of the trailer length variable as inputs, A calculation method for articulated vehicles, wherein the virtual steering angle is an angle indicating the direction of displacement of the connection point between the trailer and the tractor.

9. The present invention is applied to a combination vehicle including a tractor and a trailer towed by the tractor, causing a computer to execute a curvature variable acquisition process, a trailer length variable acquisition process, and a virtual steering angle calculation process; the curvature variable acquisition process is a process of acquiring a value of a curvature variable, the curvature variable is a variable indicating the curvature of the traveling trajectory of the trailer, the trailer length variable acquisition process is a process of acquiring a value of a trailer length variable, the trailer length variable is a variable indicating the length of the trailer, the virtual steering angle calculation process is a process of calculating a virtual steering angle using the value of the curvature variable and the value of the trailer length variable as inputs, A calculation program for articulated vehicles, wherein the virtual steering angle is an angle indicating the direction of displacement of the connection point between the trailer and the tractor.

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