Articulated vehicle control device, articulated vehicle control method, and articulated vehicle control program

Abstract

Control devices (80, 90) of an articulated vehicle (10) are configured to execute an environmental data acquisition process, a wind power prediction process, and a countermeasure process. The environmental data acquisition process is a process for acquiring environmental data that is data indicating information relating to the surrounding environment in the traveling direction of the articulated vehicle. The wind power prediction process is a process for predicting a change in wind power on the articulated vehicle on the basis of the environmental data as an input variable. The countermeasure process is a process for operating an operation target according to a different value of an operation input variable when the wind power on the articulated vehicle is predicted to increase than when the wind power on the articulated vehicle is not predicted to increase. The operation target is at least one of three systems, which are a steering system, a drive system, and a braking system. The operation input variable is a variable that determines an input signal to the operation target.

Description

Control device for a coupled vehicle, control method for a coupled vehicle, and control program for a coupled vehicle

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

[0002] Patent Document 1 below describes a control device for dealing with a so-called sway phenomenon in which a trailer shakes in a coupled vehicle. This control device reduces the sway of the trailer by brake control when the sway phenomenon occurs.

[0003] U.S. Patent Application Publication No. 2019 / 0001944

[0004] By the way, when the intensity of the wind blowing against the side of the coupled vehicle increases, the sway phenomenon tends to become prominent. However, in the case of the above device, when the sway phenomenon occurs due to an increase in the intensity of the wind blowing against the side of the coupled vehicle, it only reduces the sway of the trailer afterwards.

[0005] One aspect of this disclosure provides a control device for a motorized vehicle. The motorized vehicle comprises a tractor and a trailer towed by the tractor. The control device is configured to perform environmental data acquisition processing, wind force prediction processing, and countermeasure processing. The environmental data acquisition processing is the process of acquiring environmental data, which is data indicating information about the surrounding environment in the direction of travel of the motorized vehicle. The wind force prediction processing is the process of predicting changes in wind force on the motorized vehicle based on the environmental data as input variables. The countermeasure processing is the process of operating an object according to a value of an operation input variable that differs from the value when wind force on the motorized vehicle is predicted to increase, compared to the case when it is not predicted. The object is at least one of three: a steering system, a drive system, and a braking system. The operation input variable is a variable that defines the input signal to the object. The process of operating the object includes at least one of three: yaw response suppression processing, load increase processing, and feedback gain increase processing. The yaw response suppression processing is the process of slowing down the yaw response compared to the case when wind force is predicted to increase. The load increase process is a process that increases the load required to operate the control unit when an increase in wind force is predicted, compared to when an increase is not predicted. The control unit is a component operated by the driver to indicate their intention to steer. The feedback gain increase process is a process that increases the gain of the feedback control, where the yaw rate is the controlled variable, when an increase in wind force is predicted.

[0006] Another aspect of this disclosure provides a method for controlling a motorized vehicle. The motorized vehicle comprises a tractor and a trailer towed by the tractor. The control method includes performing an environmental data acquisition process, a wind force prediction process, and a countermeasure process. The environmental data acquisition process is a process for acquiring environmental data, which is data indicating information about the surrounding environment in the direction of travel of the motorized vehicle. The wind force prediction process is a process for predicting changes in wind force on the motorized vehicle based on the environmental data as input variables. The countermeasure process is a process for operating an object when it is predicted that the wind force on the motorized vehicle will increase, in accordance with a different value of an operation input variable than when it is not predicted. The object is at least one of three: a steering system, a drive system, and a braking system. The operation input variable is a variable that defines an input signal to the object. The process for operating the object includes at least one of three processes: yaw response suppression process, load increase process, and feedback gain increase process. The yaw response suppression process is a process for slowing down the yaw response when it is predicted that the wind force will increase, compared to when it is not predicted. The load increase process is a process that increases the load required to operate the control unit when an increase in wind force is predicted, compared to when an increase is not predicted. The control unit is a component operated by the driver to indicate their intention to steer. The feedback gain increase process is a process that increases the gain of the feedback control, where the yaw rate is the controlled variable, when an increase in wind force is predicted.

[0007] In another aspect of this disclosure, a control program for a motorized vehicle is provided. The motorized vehicle comprises a tractor and a trailer towed by the tractor. The control program includes a command to cause a computer to perform an environmental data acquisition process, a wind force prediction process, and a countermeasure process. The environmental data acquisition process is a process of acquiring environmental data, which is data indicating information about the surrounding environment in the direction of travel of the motorized vehicle. The wind force prediction process is a process of predicting a change in wind force on the motorized vehicle based on the environmental data as an input variable. The countermeasure process is a process of operating an object according to a value of an operation input variable that differs from the value when an increase in wind force on the motorized vehicle is predicted compared to when it is not predicted. The object is at least one of three: a steering system, a drive system, and a braking system. The operation input variable is a variable that defines an input signal to the object. The process of operating the object includes at least one of three: a yaw response suppression process, a load increase process, and a feedback gain increase process. The yaw response suppression process is a process that slows down the yaw response when an increase in wind force is predicted, compared to when an increase is not predicted. The load increase process is a process that increases the load required to operate the control unit when an increase in wind force is predicted, compared to when an increase is not predicted. The control unit is a component operated by the driver to indicate their intention to steer. The feedback gain increase process is a process that increases the gain of the feedback control, where the yaw rate is the controlled variable, when an increase in wind force is predicted.

[0008] Figure 1 is a perspective view showing the configuration of a motorized vehicle according to the first embodiment. Figure 2 is a diagram showing the configuration of the control system according to the same embodiment. Figure 3 is a flowchart showing the procedure of processing performed by the control system according to the same embodiment. Figure 4 is a flowchart showing the procedure of processing performed by the steering ECU according to the same embodiment. Figure 5 is a diagram illustrating a situation in which strong crosswinds are expected in the same embodiment. Figure 6 is a diagram illustrating a situation in which strong crosswinds are expected in the same embodiment. Figure 7 is a flowchart showing the procedure of processing performed by the steering ECU according to the same embodiment. Figure 8 is a time chart showing the effects of the same embodiment. Figure 9 is a flowchart showing the procedure of processing performed by the steering ECU according to the second embodiment. Figure 10 is a flowchart showing the procedure of processing performed by the steering ECU according to the third embodiment. Figure 11 is a time chart showing the effects of the same embodiment. Figure 12 is a flowchart showing the procedure of processing performed by the steering ECU according to the fourth embodiment. Figure 13 is a diagram showing the configuration of the control system according to the fifth embodiment. Figure 14 is a flowchart showing the procedure of processing performed by the steering ECU according to the same embodiment. Figure 15 is a flowchart showing the procedure of processing performed by the steering ECU according to the sixth embodiment.

[0009] <First Embodiment> The first embodiment will be described below with reference to the drawings. "Configuration of the Articulated Vehicle" As shown in Figure 1, the articulated vehicle 10 comprises a tractor 20 and a trailer 30. The tractor 20 comprises front wheels 22 and rear wheels 24. The front wheels 22 include two wheels, the right front wheel and the left front wheel, and the rear wheels 24 include two wheels, the right rear wheel and the left rear wheel. Also, Figure 1 illustrates a box-shaped trailer as the trailer 30. The trailer 30 has wheels 32. The wheels 32 include two wheels, the right wheel and the 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 component that connects the trailer 30 to the tractor 20 so that it can rotate around an axle 42. The axle 42 extends along the height direction of the tractor 20.

[0011] Figure 2 shows some of the components of the tractor 20. As shown in Figure 2, a reaction force is applied to the steering wheel 52 in the steering system 50 of the articulated vehicle 10 by a reaction force motor 54. The reaction force is a torque with the opposite sign to the torque applied by the driver to the steering wheel 52. The output voltage of the inverter 56 is applied to the terminals of the reaction force motor 54.

[0012] Furthermore, the steering system 50 includes a front wheel actuator Af and a rear wheel actuator Ar. At the front wheel actuator Af, the front wheel 22 of the steering system 50 is powered by a front wheel steering motor 60. The output voltage of the inverter 62 is applied to the terminals of the front wheel steering motor 60. At the rear wheel actuator Ar, the rear wheel 24 of the steering system 50 is powered by a rear wheel steering motor 64. The output voltage of the inverter 66 is applied to the terminals of the rear wheel steering motor 64.

[0013] The steering ECU 80 controls the torque of the reaction force motor 54 to control the control amount of the steering wheel 52, which is the object of control. Here, the control amount is the reaction force. The steering ECU 80 also controls the torque of the front wheel steering motor 60 to control the control amount of the front wheel 22, which is the object of control. Here, the control amount is the steering angle of the front wheel 22. The steering angle is the turning angle of the front wheel 22's tire. The steering ECU 80 also controls the torque of the rear wheel steering motor 64 to control the control amount of the rear wheel 24, which is the object of control. Here, the control amount is the steering angle of the rear wheel 24.

[0014] The steering ECU 80 refers to the steering torque Th detected by the torque sensor 85 for controlling the control amount. The steering torque Th is the torque input to the steering wheel 52. The steering ECU 80 also refers to the steering angle θh detected by the steering angle sensor 86 for controlling the control amount. The steering ECU 80 also refers to the rotation angle θmf of the front wheel steering motor 60 detected by the rotation angle sensor 87 for controlling the control amount. The steering ECU 80 also refers to the rotation angle θmr of the rear wheel steering motor 64 detected by the rotation angle sensor 88 for controlling the control amount.

[0015] The steering ECU 80 includes a PU 82 and a storage device 84. The PU 82 is a software processing unit such as a CPU and GPU. The storage device 84 stores a steering control program 84a.

[0016] The tractor 20 is equipped with a drive system 100. The drive system 100 includes at least one of two devices, an internal combustion engine and a rotating electric machine, which serve as thrust generating devices for the vehicle. The tractor 20 is equipped with a braking system 102. The braking system 102 includes at least one of two devices: a device that slows down the rotation of the wheels by frictional force, and a device that slows down the rotation of the wheels by converting the power of the wheels into electrical energy. The device that slows down the rotation of the wheels by converting power into electrical energy may be shared with the rotating electric machine of the drive system.

[0017] The tractor 20 is equipped with an ADASECU 90. The ADASECU 90 operates the steering system 50, the drive system 100, and the braking system 102 to control the control quantities of the coupled vehicle 10, which is the object of control. The control quantities are vehicle speed, direction of travel, etc. The drive system 100 may also include a drive control device that controls at least one of two types of engines: an internal combustion engine and a rotating electric machine. In that case, "the ADASECU 90 operates the drive system 100" means that the ADASECU 90 outputs a command signal to the drive control device. The braking system 102 may also include a brake control device that controls a device that reduces the rotation of the wheels. In that case, "the ADASECU 90 operates the braking system 102" means that the ADASECU 90 outputs a command signal to the brake control device. Furthermore, "ADASECU 90 operates the steering system 50" means that ADASECU 90 outputs a command signal to the steering ECU 80.

[0018] The ADASECU 90 refers to the vehicle speed V detected by the vehicle speed sensor 112. The ADASECU 90 also refers to the tractor yaw rate rt detected by the tractor-side yaw rate sensor 114 in order to control the control amount. The ADASECU 90 can communicate with the user interface 116. The user interface 116 is an interface into which information from the driver is input. Here, the input of information from the driver includes input of the driver's intentions. The input of the driver's intentions includes input of whether automatic steering or manual steering is desired. The input of information from the driver also includes input of information related to the trailer 30, etc. The ADASECU 90 refers to the image data Dp of the front of the coupled vehicle 10 output by the camera 118. The ADASECU 90 refers to the position data Dgps from the Global Positioning System (GPS 120). The ADASECU 90 refers to the map data 122.

[0019] The ADASECU 90 includes a PU 92 and a storage device 94. The PU 92 is a software processing unit such as a CPU or GPU. The storage device 94 stores an assist program 94a. The assist program 94a defines commands for executing automatic steering processes, etc.

[0020] "Regarding the process for understanding the trailer's status" Figure 3 shows the procedure for the process for understanding the trailer's status. The process shown in Figure 3 is executed while the ADASECU 90 and the steering ECU 80 communicate with each other. Specifically, the process on the left side of Figure 3 is realized by the PU 92 of the ADASECU 90 repeatedly executing the assist program 94a, for example, at a predetermined period. The process on the right side of Figure 3 is realized by the PU 82 of the steering ECU 80 repeatedly executing the steering control program 84a, for example, at a predetermined period. In the following, the step number of each process will be represented by a number preceded by "S".

[0021] In the series of processes shown in Figure 3, the PU 92 first determines whether an input operation has been performed via the user interface 116 to determine whether or not information regarding whether or not the trailer 30 is connected to the tractor has been input (S10). If the PU 92 determines that an input operation has been performed (S10: YES), it determines whether or not information indicating that the trailer 30 is connected has been input (S12). If the PU 92 determines that information indicating that the trailer 30 is connected has been input (S12: YES), it sets the driving mode to the trailer towing mode (S14). On the other hand, if the PU 92 determines that information indicating that the trailer 30 is not connected has been input (S12: NO), it sets the driving mode to the tractor-only mode (S16). When the PU 92 completes the processes in S14 and S16, it outputs data indicating the driving mode (mode data in the figure) to the steering ECU 80 (S18).

[0022] Furthermore, PU92 determines whether trailer information has been input via the user interface 116 (S20). The trailer information includes information on at least one of three things: the weight of the trailer 30, the position of the center of gravity of the trailer 30, and the length of the trailer 30. If PU92 determines that trailer information has been input (S20: YES), it outputs trailer data, which is data indicating the trailer information, to the steering ECU 80 (S22).

[0023] Furthermore, when PU92 completes the process in S22, or when it makes a negative determination in the processes of S10 and S20, it temporarily terminates the series of processes shown on the left side of Figure 3. Meanwhile, PU82 of the steering ECU80 determines whether or not it has received the data related to the driving mode output by the process in S18, or the trailer data output by the process in S22 (S30). If PU82 determines that it has received the data (S30: YES), it stores the received data in the storage device 84 (S32).

[0024] Furthermore, when PU 82 completes the process in S32, or when it makes a negative determination in the process in S30, it temporarily terminates the series of processes shown on the right side of Figure 3. "Sway Phenomenon Countermeasures" Figure 4 shows the procedure for processes aimed at suppressing the occurrence of the sway phenomenon. The series of processes shown in Figure 4 are realized by PU 82 repeatedly executing the steering control program 84a at a predetermined period, for example, and PU 92 of ADASECU 90 repeatedly executing the assist program 94a at a predetermined period, for example.

[0025] In the series of processes shown in Figure 4, the PU 82 of the steering ECU 80 first determines whether the steering mode is manual steering mode (S40). If the PU 82 determines that the steering mode is manual steering mode (S40: YES), it acquires the steering angle θh detected by the steering angle sensor 86 and the vehicle speed V detected by the vehicle speed sensor 112 (S42). Based on the steering angle θh, the PU 82 calculates the target front wheel steering angle base value θfb* (S44). The target front wheel steering angle base value θfb* is the base value of the target steering angle of the front wheels 22. The PU 82 determines that the target front wheel steering angle base value θfb* is a value that has a positive correlation with the steering angle θh.

[0026] Next, PU82 determines whether the driving mode is trailer towing mode or not (S46). If PU82 determines that the driving mode is tractor-only mode (S46: NO), it substitutes the target front wheel steering angle base value θfb* into the target front wheel steering angle θf* (S48).

[0027] Meanwhile, if PU82 determines that the driving mode is trailer towing mode (S46: YES), it acquires the tractor yaw rate rt (S50). Meanwhile, PU92 of ADASECU90 acquires image data Dp, position data DGPS, and map data (S52). Based on the image data Dp, position data DGPS, and map data as input variables, PU92 predicts whether the crosswind to the towed vehicle 10 will increase to a predetermined level or higher within a predetermined time (S54).

[0028] PU92 predicts, for example, that the crosswind will increase beyond a predetermined level if the area around the coupled vehicle 10 suddenly opens up within a predetermined time. Figure 5 illustrates an example of a case where the surroundings suddenly open up. As shown in Figure 5, when the coupled vehicle 10 exits a tunnel, the area around the coupled vehicle 10 suddenly opens up. In that case, it is predicted that the crosswind against the coupled vehicle 10 will increase beyond a predetermined level. Therefore, PU92 only needs to predict that the crosswind against the coupled vehicle 10 will increase beyond a predetermined level if, for example, the coupled vehicle 10 passes through the tunnel exit within a predetermined time. Other examples of cases where the surroundings suddenly open up include, for example, when exiting an area where large buildings such as skyscrapers line the side of the driving lane.

[0029] For example, as illustrated in Figure 6, PU92 may predict that the crosswind will increase beyond a predetermined level when the coupled vehicle 10 passes an oncoming vehicle 130. Returning to Figure 4, if PU82 determines that the crosswind will not increase beyond a predetermined level (S54: NO), PU82 selects map data to define the coefficient Ka (S56). Map data is data in which the vehicle speed V is the input variable and the coefficient Ka is the output variable. Note that there is not limited to one set of map data; for example, one set may be prepared for each trailer data. In that case, the optimal map data is selected based on the trailer data acquired in the above process.

[0030] PU52 obtains the correction amount Δθf, which is the output, by inputting the tractor yaw rate rt to the following phase lead compensation filter defined by the coefficient Ka (S58): (1 + Ka・s・T) / (1 + s・T) Note that the Laplace operator s and the time constant T are used in the above equation. The coefficient Ka in the above equation is calculated by PU82 using a map calculation based on the vehicle speed V as the input variable.

[0031] Map data is a set of data consisting of discrete values ​​of input variables and corresponding values ​​of output variables for each of the input variable values. A map operation is a process in which, if the value of an input variable matches any of the input variable values ​​in the map data, the corresponding value of the output variable in the map data is the result of the operation. Alternatively, if the value of an input variable does not match any of the input variable values ​​in the map data, the result of the map operation is a value obtained by interpolating the values ​​of multiple output variables included in the map data. Or, instead, if the value of an input variable does not match any of the input variable values ​​in the map data, the result of the map operation may be the value of the output variable in the map data that corresponds to the closest value among the multiple input variable values ​​included in the map data.

[0032] On the other hand, if PU82 predicts that the crosswind will increase beyond a predetermined level due to PU92 (S54: YES), it selects map data to determine the coefficient Kb (S60). Map data is data in which the vehicle speed V is the input variable and the coefficient Kb is the output variable. Note that there is not limited to one set of map data; for example, one set may be prepared for each trailer data. In that case, the optimal map data is selected based on the trailer data obtained in the above process.

[0033] PU52 obtains the output correction amount Δθf by inputting the tractor yaw rate rt to the following phase lead compensation filter defined by the coefficient Kb (S62). The correction amount Δθf calculated by the process in S62 is set to an amount that further slows down the yaw response than the correction amount Δθf calculated by the process in S58.

[0034] (1 + Kb・s・T) / (1 + s・T) Note that the above equation uses the Laplace operator s and the time constant T. The coefficient Kb in the above equation is calculated by PU82 based on the vehicle speed V as the input variable.

[0035] If PU82 completes the processes in S62 and S58, it subtracts the correction amount Δθf from the target front wheel steering angle base value θfb* and substitutes that value into the target front wheel steering angle θf* (S64). If PU82 completes the processes in S48 and S64, it obtains the front wheel steering angle θf (S66). The front wheel steering angle θf is calculated by PU82 based on the rotation angle θmf. PU82 calculates the manipulated variable for feedback control, where the front wheel steering angle θf is the controlled variable and the target front wheel steering angle θf* is the target value of the controlled variable, and substitutes this manipulated variable into the target front wheel torque Tf* (S68). Then, PU82 operates the inverter 62 by outputting an operation signal MSf corresponding to the target front wheel torque Tf* to the inverter 62 (S70). Here, if the target front wheel torque Tf* is the amount converted to the torque of the front wheel steering motor 60, the operation signal MSf becomes a signal to bring the torque of the front wheel steering motor 60 closer to the target front wheel torque Tf*.

[0036] Furthermore, PU82 and PU92 terminate the series of processes shown in Figure 4 when they complete the process in S70 or when they make a negative determination in the process in S40. The process in S44 corresponds to the base target value setting process. The process in S50 corresponds to the yaw rate acquisition process. The process in S52 corresponds to the environmental data acquisition process. The process in S54 corresponds to the wind force prediction process. The processes in S60 and S62 correspond to the yaw response suppression process. The target front wheel steering angle θf* corresponds to the operation input variable. The operation signal MSf corresponds to the input signal to the operation target.

[0037] Figure 7 shows the procedure for processing aimed at suppressing the occurrence of sway. The series of processes shown in Figure 7 are realized by the PU 82 repeatedly executing the steering control program 84a at a predetermined period, for example, and the PU 92 of the ADASECU 90 repeatedly executing the assist program 94a at a predetermined period, for example. In Figure 7, for convenience, the same step numbers are assigned to the processes corresponding to the processes shown in Figure 4.

[0038] In the series of processes shown in Figure 7, the PU 82 first determines whether the steering mode is automatic steering mode (S40a). If the PU 82 determines that the steering mode is automatic steering mode (S40a: YES), it obtains the target front wheel steering angle base value θfb* and the vehicle speed V (S42a). The target front wheel steering angle base value θfb* is a value set by the ADASECU 90. The PU 92 of the ADASECU 90 executes the assist program 94a to set the driving trajectory of the tractor 20, and then substitutes the appropriate steering angle of the front wheels 22 for driving the tractor 20 along the trajectory into the target front wheel steering angle base value θfb*. Here, "appropriate for driving the tractor 20 along the above trajectory" means appropriate when the driving mode is tractor-only mode.

[0039] If PU82 completes the process in S42a, it executes the processes in S46 to S70. "Operation and Effects of this Embodiment" Figure 8 illustrates the transition of the state when the coupled vehicle 10 is driven in a situation where a strong crosswind hits the coupled vehicle 10. The upper left figure of Figure 8 shows the transition of the lateral position of the coupled vehicle 10. In particular, in the upper left figure, the solid line shows the case when the processes in S60 to S64 are executed. Also in the upper left figure, the dashed-dot line shows the case when the target front wheel steering angle θf* is set to the target front wheel steering angle base value θfb*. In other words, the dashed-dot line shows the case when the processes in S60 to S64 are not executed. Also, the dashed-dot line in the upper left figure shows the case when a negative determination is made in the process in S46. Note that in the upper left figure, the target value of the lateral position is zero.

[0040] As shown in the figure, by performing the processes from S60 to S64, the lateral position fluctuations due to crosswinds are suppressed to the same level as when the trailer 30 is not being towed. According to the embodiment described above, the following effects and advantages can be obtained.

[0041] (1) The PU 82 executed the processes of S60 to S64 only when it was predicted that the crosswind would increase by a predetermined amount or more. And even though the PU 82 was towing the trailer 30, when it was predicted that the crosswind would not increase by a predetermined amount or more, the PU 82 executed the processes of S56, S58, and S64. The processes of S56, S58, and S64 are processes with a smaller degree of dulling of the yaw response compared to the processes of S60 to S64. Thereby, it is possible to suppress a situation where the yaw response is dulled more than necessary compared to the case where the processes of S60 to S64 are always executed.

[0042] (2) When the PU 82 is not towing the trailer 30, the PU 82 does not execute the processes of S56, S58, and S64. Therefore, when towing the trailer 30, the yaw response can be dulled compared to the case of not towing. Thereby, it is possible to suppress the occurrence of a sway phenomenon even when towing the trailer 30 and to suppress the excessive dulling of the yaw response when not towing the trailer 30.

[0043] <Second Embodiment> Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment.

[0044] FIG. 9 shows a procedure of a process aimed at suppressing the occurrence of a sway phenomenon according to the present embodiment. The series of processes shown in FIG. 9 is realized by the PU 82 repeatedly executing the steering control program 84a, for example, at a predetermined cycle, and the PU 92 of the ADAS ECU 90 repeatedly executing the assist program 94a, for example, at a predetermined cycle. In FIG. 9, for the processes corresponding to the processes shown in FIG. 4, the same step numbers are given for convenience.

[0045] In the series of processes shown in FIG. 9, when the PU 82 completes the process of S42, the PU 82 calculates a target front wheel steering angle θf* based on the steering angle θh (S44a). Next, the PU 82 determines whether the driving mode is the trailer towing mode (S46). When the PU 82 determines that the driving mode is the tractor-alone mode (S46: NO), the PU 82 executes the processes of S66 to S70.

[0046] On the other hand, if PU82 determines that the driving mode is trailer towing mode (S46: YES), and if PU92 determines that the crosswind will not increase beyond a predetermined level (S54: NO), it selects map data for calculating the gain Ga (S80). The map data is data in which the vehicle speed V is the input variable and the gain Ga is the output variable. Note that there is not limited to one set of map data; for example, one set may be prepared for each trailer. In that case, the optimal map data is selected based on the trailer data obtained in the above process. Then, PU82 substitutes the value obtained by multiplying the target front wheel steering angle θf* by the gain Ga into the target rear wheel steering angle θr* (S82). The target rear wheel steering angle θr* is the target value of the steering angle of the rear wheels 24 of the tractor 20. The gain Ga is calculated by PU82 using the above map data. Note that the gain Ga is set to a value in which the sideslip angle β of the tractor 20 becomes 0. The gain Ga may be calculated by setting the sideslip angle β to zero in vehicle models such as two-wheeled vehicles.

[0047] On the other hand, if PU92 determines that the crosswind increases beyond a predetermined level (S54: YES), map data for calculating the gain Gb is selected (S84). Map data is data in which vehicle speed V is the input variable and gain Gb is the output variable. Note that there is not limited to one set of map data; for example, one set may be prepared for each trailer data. In that case, the optimal map data is selected based on the trailer data obtained in the above process. Then, PU82 substitutes the value obtained by multiplying the target front wheel steering angle θf* by the gain Gb into the target rear wheel steering angle θr* (S84). The target rear wheel steering angle θr* is the target value of the steering angle of the rear wheels 24 of the tractor 20. The gain Gb is calculated by PU82 using the above map data. Note that the gain Gb is set to a value in which the sideslip angle β of the tractor 20 becomes 0. The gain Gb may also be calculated by setting the sideslip angle β to zero in vehicle models such as two-wheel models. It should be noted that the vehicle model used to calculate the gain Ga differs from the crosswind effect in this case.

[0048] When the processing of S82 and S86 is completed, the PU82 calculates the front-wheel steering angle θf and the rear-wheel steering angle θr (S88). The rear-wheel steering angle θr is calculated by the PU82 using the rotation angle θmr. The PU82 calculates the target front-wheel torque Tf* and the target rear-wheel torque Tr* (S90). Here, the PU82 calculates the target front-wheel torque Tf* by the above-described processing. Further, the PU82 calculates the operation amount of the feedback control in which the rear-wheel steering angle θr is the control amount and the target rear-wheel steering angle θr* is the target value of the control amount, and substitutes the operation amount into the target rear-wheel torque Tr*.

[0049] Then, the PU82 outputs the operation signal MSf to the inverter 62 and outputs the operation signal MSr to the inverter 66 (S92). Here, when the target rear-wheel torque Tr* is the amount converted into the torque of the rear-wheel steering motor 64, the operation signal MSr becomes a signal for bringing the torque of the rear-wheel steering motor 64 closer to the target rear-wheel torque Tr*.

[0050] Note that when the processing of S70 and S92 is completed and when a negative determination is made in the processing of S40, the PU82 once terminates the series of processing shown in FIG. 9. The processing of S84 and S86 corresponds to the yaw response suppression processing. The target rear-wheel steering angle θr* corresponds to the operation input variable. The operation signal MSr corresponds to the input signal to the operation target.

[0051] Incidentally, in the automatic steering mode, the PU82 executes the processing in which the processing of S42 and S44a is replaced with the processing of S42a in the processing of FIG. 9. <Third Embodiment> Hereinafter, the third embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment.

[0052] In the present embodiment, in the trailer towing mode, the drive system 100 and the braking system 102 are used to blunt the yaw response. FIG. 10 shows a procedure of processing aimed at suppressing the occurrence of the sway phenomenon according to the present embodiment. The series of processing shown in FIG. 10 is realized by the PU92 repeatedly executing the assist program 94a, for example, at a predetermined cycle.

[0053] In the series of processes shown in Figure 10, PU92 first determines whether or not it is in trailer towing mode (S46). If PU92 determines that it is in trailer towing mode (S46: YES), it obtains the vehicle speed V (S42a). Then, if PU92 determines that the crosswind will not increase beyond a predetermined level (S54: NO), it selects map data for calculating the threshold ωhath (S100). Map data is data in which the vehicle speed V is the input variable and the threshold ωhath is the output variable. Note that there is not limited to one set of map data; for example, one set may be prepared for each trailer data. In that case, the optimal map data is selected based on the trailer data obtained in the above process. Then, PU82 determines whether or not the absolute value of the steering angular velocity ωh is greater than or equal to the threshold ωhath (S102). Here, the steering angular velocity ωh is calculated by PU82 based on the steering angle θh as the input variable. Furthermore, the threshold ωhath is calculated by PU82 using map data selected by processing S80 based on the vehicle speed V as the input variable.

[0054] This process determines whether the conditions for executing a process to slow down the yaw response have been met. Here, the threshold ωhath is set to the lower limit of the absolute value of the steering angular velocity ωh, which is prone to causing sway phenomena. PU92 changes the threshold ωhath according to the vehicle speed V, provided that the threshold ωhath when the vehicle speed V is large is less than or equal to the threshold ωhath when the vehicle speed V is small.

[0055] If PU92 determines that the threshold ωhath is greater than or equal to (S102: YES), it sets the difference in driving force between the inner and outer rings (S104). This process reduces the yaw response by applying a yaw moment in the opposite direction to the turning direction during turning. This process reduces the relative magnitude of the driving force of the outer ring to the driving force of the inner ring.

[0056] PU92 operates the drive system 100 and the braking system 102 to create the driving force difference set by the process in S104 (S106). For example, PU92 operates the braking system 102 to apply braking force to the outer wheel and operates the drive system 100 to compensate for the output reduction caused by the braking force. However, if the drive system 100 can change the distribution of driving force to each wheel, the role of the drive system 100 is not limited to compensating for the total output reduction. For example, in addition to the process of applying braking force to the outer wheel by the braking system 102, PU92 may also perform a process by the drive system 100 to reduce the driving force of the outer wheel relative to the driving force of the inner wheel.

[0057] Note that the process in S106 does not mean that the driving force of the outer wheel is made smaller than the driving force of the inner wheel. The process in S106 is to make the relative magnitude of the driving force of the outer wheel to the driving force of the inner wheel smaller than the value in the tractor-only mode.

[0058] On the other hand, if PU92 determines that the crosswind is increasing beyond a predetermined level (S54: YES), it selects map data to calculate the threshold ωhbth (S108). Map data is data in which the vehicle speed V is the input variable and the threshold ωhbth is the output variable. Note that there is not limited to one set of map data; for example, one set may be prepared for each trailer data. In that case, the optimal map data is selected based on the trailer data acquired in the above process. Then, PU92 performs preload processing (S110). This process adjusts the pressure of the brake actuator of the braking system 102 in advance so that the braking force on the outer wheel can be increased quickly. Then, PU92 determines whether the absolute value of the steering angular velocity ωh is greater than or equal to the threshold ωhbth (S112). Here, the threshold ωhbth is calculated by PU82 using the map data selected in the S108 process based on the vehicle speed V as the input variable.

[0059] This process determines whether the conditions for executing a process to slow down the yaw response have been met. Here, the threshold ωhbth is set to the lower limit of the absolute value of the steering angular velocity ωh, which is likely to cause a sway phenomenon when there is a strong crosswind on the coupled vehicle 10. PU92 changes the threshold ωhbth according to the vehicle speed V, provided that the threshold ωhbth when the vehicle speed V is large is less than or equal to the threshold ωhbth when the vehicle speed V is small.

[0060] If PU92 determines that the threshold ωhbth is greater than or equal to (S112: YES), it sets the difference in driving force between the inner and outer rings (S114). This process reduces the yaw response by applying a yaw moment in the opposite direction to the turning direction during turning. This process reduces the relative magnitude of the driving force of the outer ring to the driving force of the inner ring. The process in S114 reduces the degree of yaw response slowing down more than the process in S104.

[0061] PU92 operates the drive system 100 and the braking system 102 to generate the driving force difference set by the process in S14 (S106). Note that PU92 terminates the series of processes shown in Figure 10 when it completes the process in S106, or when it makes a negative determination in the processes of S46, S102, and S114. Note that the processes in S108 to S114 correspond to the yaw response suppression process. The process in S110 corresponds to the preload process. The operation signals for the drive system 100 and the braking system 102 correspond to the input signals to the operated objects. The driving force difference corresponds to the operation input variable.

[0062] "Operation and Effects of This Embodiment" When the absolute value of the steering angular velocity ωh in trailer towing mode is greater than or equal to the threshold ωhath, the PU 92 superimposes a yaw moment in the opposite direction to the turning direction by operating the drive system 100 and the braking system 102. In other words, the PU 92 controls the value obtained by subtracting the yaw moment in trailer towing mode from the yaw moment in tractor-only mode to an amount opposite to the yaw moment in tractor-only mode. As a result, when the turning operation instruction is the same in trailer towing mode and tractor-only mode, an increase in the yaw response in trailer towing mode is suppressed.

[0063] Furthermore, when strong crosswinds are predicted in trailer towing mode, and the absolute value of the steering angular velocity ωh exceeds a threshold ωhbth, the PU92 superimposes a yaw moment in the opposite direction to the turning direction by operating the drive system 100 and the braking system 102. The magnitude of the superimposed yaw moment at this time is set to a value greater than the magnitude of the yaw moment when strong crosswinds are not predicted. This makes it possible to sufficiently suppress the occurrence of sway phenomena even when strong crosswinds are present. In addition, when it is predicted that the crosswind will not rise above a certain level, the magnitude of the superimposed yaw moment can be reduced to suppress excessive blunting of the yaw response.

[0064] Figure 11 illustrates the progression of the state when a coupled vehicle 10 is driven under conditions where a strong crosswind is hitting the vehicle. The upper left figure of Figure 11 shows the progression of the lateral position of the coupled vehicle 10. Specifically, in the upper left figure, the solid line indicates the case when processes S106, S108-S114 are executed. Also in the upper left figure, the dashed-dot line indicates the case when processes S100-S106 and S108-S114 are not executed. Also in the upper left figure, the dashed-dot line indicates the case when the tractor 20 is not towing the trailer 30. Also in the upper left figure, the target value of the lateral position is zero.

[0065] As shown in the figure, by performing the processes from S108 to S114, the lateral position fluctuation due to crosswinds is suppressed to the same level as when the trailer 30 is not being towed. <Fourth Embodiment> The fourth embodiment will now be described below, focusing on the differences from the first embodiment with reference to the drawings.

[0066] In the above embodiment, the yaw response was slowed down when it was predicted that the crosswind would increase beyond a predetermined level. In contrast, in this embodiment, the gain of the closed-loop control, where the yaw rate is the controlled variable, is increased.

[0067] Figure 12 shows the procedure for the process related to increasing the gain. The process shown in Figure 12 is realized by the PU 82 repeatedly executing the program stored in the storage device 84, for example, at a predetermined period. In Figure 12, for convenience, the same step numbers are assigned to the processes corresponding to the process shown in Figure 4.

[0068] In the series of processes shown in Figure 12, when PU82 executes processes S42 and S44, it calculates the target yaw rate r* based on the target front wheel steering angle base value θfb* and the vehicle speed V as input variables (S120). Then, PU82 calculates the manipulated variable Mff for open-loop control, where the tractor yaw rate rt is the controlled variable, based on the target yaw rate r* as an input variable (S122). PU82 also obtains the tractor yaw rate rt (S124). If PU82 determines that the driving mode is not trailer towing mode (S46: NO), it sets the feedback gain, which is the gain for closed-loop control where the tractor yaw rate is the controlled variable, to the non-towing value (S126).

[0069] On the other hand, if PU82 determines that the driving mode is trailer towing mode (S46: YES) and determines that the crosswind will not increase beyond a predetermined level due to PU92 (S54: NO), it sets the above feedback gain to the normal value during towing (S128). The normal value during towing is a larger value than the value when not towing. Conversely, if PU82 determines that the crosswind will increase beyond a predetermined level due to PU92 (S54: YES), it sets the above feedback gain to the value for crosswinds (S130). The value for crosswinds is a larger value than the normal value during towing.

[0070] If the processes in S126, S128, and S130 are completed, PU82 calculates the manipulated variable Mfb for closed-loop control, where the tractor yaw rate rt is the target value of the controlled variable (S132). Then, PU82 adds the manipulated variables Mff and Mfb to the target front wheel steering angle base value θfb* and substitutes this value into the target front wheel steering angle θf* (S134). Then, PU82 executes the processes in S68 and S70. Note that the manipulated variable Mfb corresponds to the control input variable. The process in S130 corresponds to the feedback gain increase process.

[0071] Thus, in this embodiment, the PU 82 increases the feedback gain when towing the trailer 30 compared to when not towing it. This suppresses fluctuations in the tractor yaw rate rt caused by towing the trailer 30. Furthermore, the PU 82 increases the feedback gain even further when towing the trailer 30 and when strong crosswinds are expected. This suppresses fluctuations in the tractor yaw rate rt caused by crosswinds.

[0072] <Fifth Embodiment> The fifth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings.

[0073] "Prerequisite Configuration" Figure 13 shows some of the components of the tractor 20. For convenience, the same reference numerals are used in Figure 13 for components that correspond to those shown in Figure 2.

[0074] As shown in Figure 13, the steering wheel 52 of the steering system 50 is capable of transmitting power to the front wheels 22 via the steering shaft 58. Torque from the assist motor 54a is applied to the steering shaft 58. The output voltage of the inverter 56a is applied to each terminal of the assist motor 54a. The inverter 56a is operated by the steering ECU 80. The steering ECU 80 refers to the rotation angle θm of the assist motor 54a detected by the rotation angle sensor 83a.

[0075] "Measures to prevent sway phenomenon" Figure 14 shows the procedure for processing aimed at suppressing the occurrence of the sway phenomenon. The series of processes shown in Figure 14 are realized by the PU 82 repeatedly executing the steering control program 84a at a predetermined period, for example, and the PU 92 of the ADASECU 90 repeatedly executing the assist program 94a at a predetermined period, for example.

[0076] In the series of processes shown in Figure 14, the PU 82 first acquires the vehicle speed V, steering angle θh, and steering torque Th (S140). The steering angle θh is calculated by the PU 82 based on the rotation angle θm. Next, the PU 82 acquires the previous value of the axial force Taf, which is calculated by the process in S158 described later (S142).

[0077] Next, PU82 calculates the target steering torque base value Thb* according to the previous value of the axial force Taf and the vehicle speed V (S144). For example, PU82 may change the target steering torque base value Thb* according to the axial force Taf, provided that the target steering torque base value Thb* when the axial force Taf is large is greater than or equal to the target steering torque base value Thb* when the axial force Taf is small. Alternatively, PU82 may change the target steering torque base value Thb* according to the vehicle speed V, provided that the target steering torque base value Thb* when the vehicle speed V is large is greater than or equal to the target steering torque base value Thb* when the vehicle speed V is small.

[0078] Specifically, PU82 may perform a map calculation to determine the target steering torque base value Thb* according to the axial force Taf and vehicle speed V, provided that map data is stored in advance. Here, the map data is data in which the axial force Taf and vehicle speed V are input variables and the target steering torque base value Thb* is the output variable.

[0079] Next, PU82 determines whether or not it is in trailer towing mode (S46). If PU82 determines that it is not in trailer towing mode (S46: NO), it substitutes the target steering torque base value Thb* for the target steering torque Th* (S146).

[0080] On the other hand, if PU82 determines that it is in trailer towing mode (S46: YES), and if PU92 determines that the crosswind will not increase beyond a predetermined level (S54: NO), it selects map data for calculating the gain Kha (S148). The map data is data in which the vehicle speed V is the input variable and the gain Kha is the output variable. Note that there is not limited to one map data set; for example, one may be prepared for each trailer data set. In that case, the optimal map data is selected based on the trailer data acquired in the above process. Then PU82 assigns the value obtained by multiplying the target steering torque base value Thb* by the gain Kha to the target steering torque Th* (S150). Note that the gain Kha is greater than "1". Therefore, the absolute value of the target steering torque Th* is greater than the absolute value of the target steering torque base value Thb*.

[0081] On the other hand, if PU82 determines that it is in trailer towing mode (S46: YES), and if PU92 determines that the crosswind will increase beyond a predetermined level (S54: YES), it selects map data to calculate the gain Khb (S152). Map data is data in which the vehicle speed V is the input variable and the gain Khb is the output variable. Note that there is not limited to one set of map data; for example, one set may be prepared for each trailer data. In that case, the optimal map data is selected based on the trailer data obtained in the above process. Then PU82 substitutes the value obtained by multiplying the target steering torque base value Thb* by the gain Khb into the target steering torque Th* (S154). Note that if the vehicle speed V is the same, the gain Khb is a larger value than the gain Kha.

[0082] When PU82 completes the processes in S146, S150, and S154, it calculates the manipulated variable Ts for closed-loop control where the steering torque Th is the controlled variable and the target steering torque Th* is the target value of the controlled variable (S156). Here, closed-loop control may be, for example, the sum of the output value of a proportional element whose input is the value obtained by subtracting the target steering torque Th* from the steering torque Th, and the output value of a differential element whose input is the value obtained by subtracting the target steering torque Th* from the steering torque Th. Note that the manipulated variable Ts may include the manipulated variable for open-loop control where the steering torque Th is the controlled variable.

[0083] Next, PU82 substitutes the value obtained by adding the steering torque Th to the manipulated variable Ts into the axial force Taf (S158). Then, PU82 calculates the assist torque Ta from the assist motor 54a according to the axial force Taf (S160). Specifically, PU82 can, for example, calculate the target value of the steering angle θh from the axial force Taf according to the reference model, and then calculate the assist torque Ta as the manipulated variable for feedback control where the steering angle θh is the controlled variable. Then, PU82 operates the inverter 56a by outputting an operation signal MSa corresponding to the assist torque Ta to the inverter 56a (S162).

[0084] When PU82 completes the process in S162, it terminates the series of processes shown in Figure 14. The operation signal MSa corresponds to the input signal to the target of operation. The processes in S152 and S154 correspond to the load increase process.

[0085] "Operation and Effects of This Embodiment" In trailer towing mode, PU82 substitutes the target steering torque Th* with a value obtained by multiplying the target steering torque base value Thb* by a gain Kha. As a result, in trailer towing mode, the torque required for turning the steering wheel 52 becomes larger. On the other hand, when the steering wheel 52 is rotated equally in trailer towing mode and tractor-only mode, the yaw response is higher in trailer towing mode than in tractor-only mode. Therefore, in this embodiment, when the steering torque Th is the same in trailer towing mode and tractor-only mode, the higher yaw response in trailer towing mode than in tractor-only mode is suppressed.

[0086] Furthermore, in trailer towing mode, if crosswinds are expected to increase beyond a predetermined level, PU82 substitutes the target steering torque base value Thb* multiplied by gain Khb into the target steering torque Th*. Gain Khb is greater than gain Kha. Therefore, in trailer towing mode, if strong crosswinds are expected, the torque required for turning the steering wheel 52 will be greater than in the case where crosswinds are not expected. When crosswinds are strong, the behavior of the coupled vehicle 10 is more likely to become unstable due to the turning operation of the steering wheel 52 compared to when there are no strong crosswinds. Therefore, by increasing the torque required for turning the steering wheel 52 when crosswinds are strong, the behavior of the coupled vehicle 10 can be more easily stabilized.

[0087] <Sixth Embodiment> The sixth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings.

[0088] In the above embodiment, when performing a process to slow down the yaw response in trailer towing mode when it is predicted that the crosswind will increase beyond a predetermined level, the standard for the strength of the crosswind was fixed. In contrast, in this embodiment, the standard for the strength of the crosswind is changed according to the specifications of the trailer 30.

[0089] Figure 15 shows the procedure for processing aimed at suppressing the sway phenomenon according to this embodiment. The series of processes shown in Figure 15 are realized by the PU 82 repeatedly executing the steering control program 84a at a predetermined period, for example, and the PU 92 of the ADASECU 90 repeatedly executing the assist program 94a at a predetermined period, for example. In Figure 15, the processes corresponding to the processes shown in Figure 4 are given the same step numbers for convenience.

[0090] In the series of processes shown in Figure 15, after executing the process in S52, PU92 determines whether or not the crosswind criteria corresponding to the trailer data are met (S54a). For example, PU92 should predict that the crosswind will increase even if the crosswind is weak, as the specifications of the trailer 30 are more likely to cause a sway phenomenon.

[0091] Furthermore, PU82 proceeds to either process S56 or S60 depending on whether PU92 determines that the process in S54a is positive or negative. Process S54a corresponds to wind speed prediction processing.

[0092] <Other Embodiments> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0093] "Regarding Yaw Response Suppression Processing" - In the processing shown in Figures 4 and 7, PU82 sets a coefficient Ka according to the vehicle speed V, but is not limited to this. For example, the coefficient Ka may be a value set according to the trailer data and may be a value set independently of the vehicle speed V.

[0094] - The process in which the tractor yaw rate rt is the input and the target front wheel steering angle base value θfb* is the output is not limited to the process that utilizes phase lead compensation. For example, the process may be one in which the target front wheel steering angle base value θfb* is corrected by multiplying the time derivative of the tractor yaw rate rt by a proportional gain. In that case, the PU 82 may set the proportional gain based on at least one of two factors: vehicle speed V and trailer information.

[0095] The process in which the yaw rate is the input and the output is a corrected value of the target front wheel steering angle base value θfb* is not limited to the process in which only the tractor yaw rate rt is the input. For example, the process may also be one in which the yaw rate of the trailer 30 is the input. Alternatively, the process may also be one in which both the tractor yaw rate rt and the yaw rate of the trailer 30 are the inputs.

[0096] In the process shown in Figure 9, PU82 sets gains Ga and Gb according to the vehicle speed V, but is not limited to this. For example, the gains Ga and Gb may be values ​​set according to the trailer data and independent of the vehicle speed V.

[0097] The yaw response suppression process, which includes setting the target rear wheel steering angle θr* according to the target front wheel steering angle θf*, is not limited to the process shown in Figure 9. For example, it may include a process to set the target steering angle of the trailer in addition to the target rear wheel steering angle θr* according to the target front wheel steering angle θf*. However, in that case, the trailer 30 shall be equipped with actuators that steer the wheels 32.

[0098] The yaw response processing, which includes reducing the relative magnitude of the driving force of the outer wheels of the tractor 20 to the driving force of the inner wheels of the tractor 20 when a strong crosswind is predicted, is not limited to the processing described above. For example, the yaw response suppression processing including the above processing may be a process that manipulates the driving torque by the drive system 100. This process can be achieved by changing the power distribution of the drive system 100 between the inner and outer wheels. Alternatively, the yaw response suppression processing including the above processing may be a process that manipulates only the braking force by the braking system 102.

[0099] In the process shown in Figure 10, PU82 sets thresholds ωhath and ωhbth according to the vehicle speed V, but it is not limited to this. For example, PU82 may set thresholds ωhath and ωhbth according only to the trailer data.

[0100] - The yaw response suppression process is not limited to the processes described in the above embodiments and modified examples. The yaw response suppression process may, for example, be a process in which the value obtained by multiplying the first-order time derivative of the tractor yaw rate rt by a negative gain is added to the target front wheel steering angle base value θfb* and the result is substituted into the target front wheel steering angle θf*. Alternatively, for example, the yaw response suppression process may be a process in which the value obtained by multiplying the first-order time derivative of the trailer yaw rate by a negative gain is added to the target front wheel steering angle base value θfb* and the result is substituted into the target front wheel steering angle θf*. Alternatively, for example, the yaw response suppression process may be a process in which the value obtained by adding the product of the above two values ​​to the target front wheel steering angle base value θfb* and the result is substituted into the target front wheel steering angle θf*.

[0101] It is not necessary that the processes in Figure 4 or Figure 7, the processes in Figure 9, and the processes in Figure 10 be executed exclusively. For example, both the processes in Figure 4 and Figure 9 may be executed. Also, for example, both the processes in Figure 4 and Figure 10 may be executed.

[0102] "Regarding Load Increase Processing" - In the processing shown in Figure 14, PU82 sets the gain Khb according to the vehicle speed V, but is not limited to this. For example, the gain Khb may be a value set according to the trailer data and independent of the vehicle speed V.

[0103] - The process of operating the steering system in accordance with the value of an input variable determined to increase the force required by the driver to operate the steering wheel 52 is not limited to a process that includes feedback control of the steering torque Th. The process of operating the steering system may include a process in which the steering torque Th is the input and the assist torque Ta, which is the amount of operation for open-loop control, is the output, and a process of operating the inverter 56a in accordance with the assist torque Ta. In that case, the process of operating the steering system in accordance with the value of an input variable determined to increase the force required by the driver to operate the steering wheel 52 may be a process that reduces the absolute value of the assist torque Ta.

[0104] - It is not mandatory that the process of operating the steering system in accordance with the value of an input variable, which is determined to increase the force required by the driver to operate the steering wheel 52, be applied to a steering system in which the steering wheel 52 and the steering wheels are connected. That is, for example, in the configuration illustrated in Figure 2, the absolute value of the target steering torque Th* may be increased.

[0105] "Regarding the Feedback Gain Increase Process" - The feedback gain increase process is not limited to increasing the gain of a feedback control where the tractor yaw rate rt is the controlled variable. For example, the feedback gain increase process may be a process that increases the gain of a feedback control where the trailer yaw rate is the controlled variable. Also, for example, the feedback gain increase process may be a process that increases the gain of a feedback control where both the tractor yaw rate rt and the trailer yaw rate are controlled variables.

[0106] - The manipulated variable in the feedback gain increase process is not necessarily the front wheel steering angle θf. The manipulated variable in the feedback gain increase process may be, for example, the rear wheel steering angle θr. Alternatively, the manipulated variable in the feedback gain increase process may be both the front wheel steering angle θf and the rear wheel steering angle θr. Alternatively, the manipulated variable in the feedback gain increase process may be the z-axis moment Mz.

[0107] Regarding the countermeasures: It is not mandatory that the countermeasures consist of only one of the following: yaw response suppression, load increase, or feedback gain increase. For example, the countermeasures may include yaw response suppression and load increase.

[0108] "Regarding Wind Force Prediction Processing" - Wind force prediction processing is not limited to predicting that crosswinds will strengthen in the situations shown in Figures 5 and 6. Wind force prediction processing may include, for example, processing to predict that crosswinds will strengthen based on the fact that there is a gap in the windbreak wall. Also, for example, wind force prediction processing may include processing to predict that crosswinds will strengthen when the vehicle is on a bridge. Also, for example, wind force prediction processing may include processing to predict that crosswinds will strengthen when environmental data transmitted from outside the vehicle, such as environmental data from a preceding vehicle, indicates that there are strong crosswinds.

[0109] "Regarding Environmental Data Acquisition Processing" - It is not mandatory that the environmental data acquisition processing involves acquiring image data Dp, location data DGPS, and map data as environmental data. For example, the environmental data acquisition processing may involve acquiring distance point data from LIDAR as environmental data. Alternatively, as described in "Regarding Wind Force Prediction Processing," the environmental data acquisition processing may involve acquiring environmental data transmitted from outside the vehicle in the direction of travel.

[0110] Regarding the control unit: The control unit used by the driver to input their steering intentions is not limited to the steering wheel 52. For example, a joystick may also be used.

[0111] Regarding the control device: In the above embodiment, the ADASECU 90 may perform some of the processing performed by the steering ECU 80.

[0112] - The ADASECU 90 and the steering ECU 80 may be integrated. - The control device is not limited to one that executes software processing. For example, it may include a dedicated hardware circuit such as an ASIC that executes at least a part of the processing performed in the above embodiment. That is, the control device may include a processing circuit having any of the following configurations (a) to (c): (a) A processing circuit comprising a processing device that executes all of the above processing according to a program, and a program storage device such as a storage device that stores the program. (b) A processing circuit comprising a processing device and a program storage device that execute a part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing. (c) A processing circuit comprising a dedicated hardware circuit that executes all of the above processing. Here, there may be multiple software execution devices comprising a processing device and a program storage device. Also, there may be multiple dedicated hardware circuits.

[0113] Regarding the control entity: For example, the driver's mobile terminal may perform part of the above processing. That is, for example, the mobile terminal may perform the processing in S50 and S52.

[0114] "Other" - For example, in the first, second, and fourth embodiments, the tractor 20 does not need to be equipped with a rear wheel actuator Ar.

Claims

1. A control device for controlling a combined vehicle comprising a tractor and a trailer towed by the tractor, configured to perform environmental data acquisition processing, wind force prediction processing, and countermeasure processing, wherein the environmental data acquisition processing is the process of acquiring environmental data which is data indicating information about the surrounding environment in the direction of travel of the combined vehicle, the wind force prediction processing is the process of predicting a change in wind force on the combined vehicle based on the environmental data as an input variable, the countermeasure processing is the process of operating the target according to a value of an operation input variable that differs from the case when an increase in wind force on the combined vehicle is predicted, the target is at least one of three: steering system, drive system, and braking system, the operation input variable is a variable that defines an input signal to the target, the process of operating the target includes at least one of three: yaw response suppression processing, load increase processing, and feedback gain increase processing, the yaw response suppression processing is the process of slowing down the yaw response compared to the case when an increase in wind force is predicted, The load increase process is a process that increases the load required to operate the control unit when an increase in wind force is predicted, compared to when an increase is not predicted, the control unit is a component operated by the driver to indicate their intention to steer, and the feedback gain increase process is a process that increases the gain of feedback control, where the yaw rate is the controlled variable, when an increase in wind force is predicted, the control device for a coupled vehicle.

2. The control device for a coupled vehicle according to claim 1, wherein the countermeasurement process includes the yaw response suppression process, and the yaw response suppression process is a process of operating the target to be operated in accordance with the value of the operation input variable which is determined to slow down the yaw response to the steering input in a manual driving mode in which the tractor is steered in accordance with the steering input by the driver.

3. The control device for a motorized vehicle according to claim 1, wherein the countermeasurement process includes the yaw response suppression process, the yaw response suppression process is a process that operates the target to be operated according to the value of the operation input variable when the automatic steering process is executed, and the value of the operation input variable is determined to slow down the yaw response when the tractor turns with the same curvature as when the wind force is not expected to increase, when an increase in wind force is expected.

4. A control device for a coupled vehicle according to claim 1, configured to perform a base target value setting process for setting a base target value and a yaw rate acquisition process for acquiring a yaw rate, wherein the base target value is a base value of the target value of the steering angle of the steering wheels, and the yaw response suppression process includes a process for correcting the base target value based on the yaw rate as an input variable, and a process for operating the steering system according to the corrected base target value as an operation input variable.

5. The control device for a coupled vehicle according to claim 1, wherein the yaw response suppression process includes a process of operating at least one of the braking system and the drive system to reduce the relative magnitude of the driving force of the outer wheel of the tractor to the driving force of the inner wheel of the tractor when the tractor is turning, compared to when the wind force is not expected to increase, when the wind force is expected to increase.

6. The control device for a coupled vehicle according to claim 5, wherein the yaw response suppression process includes a process for operating the braking system, the braking system includes a hydraulic actuator and is configured to perform a preload process, and the preload process is a process for adjusting the hydraulic pressure of the hydraulic actuator prior to performing the yaw response suppression process.

7. The control device for a coupled vehicle according to claim 1, wherein the countermeasure processing includes the load increase processing, and the load increase processing includes, when it is predicted that the wind force will increase, processing to operate the steering system in accordance with a value of the operation input variable determined to be greater than when it is predicted that the force required by the driver to operate the operation unit is greater than when it is predicted that the wind force will not increase.

8. The control device for a coupled vehicle according to claim 1, wherein the countermeasure process includes a process of changing the value of the operation input variable based on the vehicle speed as an input variable when an increase in wind force is predicted.

9. The control device for a coupled vehicle according to claim 1, wherein the countermeasurement process includes the feedback gain increase process, the value of the operation input variable is calculated according to the operation amount of a closed-loop control in which the yaw rate is the controlled amount, and the feedback gain increase process includes a process to increase the gain of the closed-loop control when it is predicted that the wind force will increase.

10. A control device for a connected vehicle according to claim 1, configured to perform a trailer data acquisition process, wherein the trailer data acquisition process is a process for acquiring trailer data which is at least one of three pieces of data: data indicating the weight of the trailer, data indicating the center of gravity of the trailer, and data indicating the height of the trailer, and the wind force prediction process includes a process for changing the criteria for predicting an increase in wind force based on the trailer data as an input variable.

11. A control method for a connected vehicle comprising a tractor and a trailer towed by the tractor, comprising: execution of environmental data acquisition processing; execution of wind force prediction processing; and execution of countermeasure processing, wherein the environmental data acquisition processing is the process of acquiring environmental data which is data indicating information about the surrounding environment in the direction of travel of the connected vehicle; the wind force prediction processing is the process of predicting a change in wind force on the connected vehicle based on the environmental data as an input variable; the countermeasure processing is the process of operating the target according to a value of an operation input variable that differs from the case when an increase in wind force on the connected vehicle is predicted, compared to the case when an increase is not predicted, wherein the target is at least one of three: a steering system, a drive system, and a braking system; the operation input variable is a variable that defines an input signal to the target; the process of operating the target includes at least one of three: yaw response suppression processing, load increase processing, and feedback gain increase processing, wherein the yaw response suppression processing is the process of slowing down the yaw response compared to the case when an increase in wind force is predicted, compared to the case when an increase is not predicted. A method for controlling coupled vehicles, wherein the load increase process is a process that increases the load required to operate the control unit when an increase in wind force is predicted, compared to when an increase is not predicted, the control unit is a component operated by the driver to indicate their intention to steer, and the feedback gain increase process is a process that increases the gain of feedback control, where the yaw rate is the controlled variable, when an increase in wind force is predicted.

12. A control program for controlling a combined vehicle comprising a tractor and a trailer towed by the tractor, the program including a command to cause a computer to perform an environmental data acquisition process, a wind force prediction process, and a countermeasure process, wherein the environmental data acquisition process is a process for acquiring environmental data which is data indicating information about the surrounding environment in the direction of travel of the combined vehicle, the wind force prediction process is a process for predicting a change in wind force on the combined vehicle based on the environmental data as an input variable, the countermeasure process is a process for operating the target of control according to a value of an operation input variable that differs from the case when an increase in wind force on the combined vehicle is predicted, the target of control is at least one of three: a steering system, a drive system, and a braking system, the operation input variable is a variable that defines an input signal to the target of control, the process for operating the target of control includes at least one of three processes: yaw response suppression process, load increase process, and feedback gain increase process, the yaw response suppression process is a process for slowing down the yaw response compared to the case when an increase in wind force is predicted, The load increase process is a process that increases the load required to operate the control unit when an increase in wind force is predicted, compared to when an increase is not predicted, the control unit is a component operated by the driver to indicate their intention to steer, and the feedback gain increase process is a process that increases the gain of feedback control, where the yaw rate is the controlled variable, when an increase in wind force is predicted, a control program for coupled vehicles.

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