Control device for coupled vehicles, method for controlling coupled vehicles, and control program for coupled vehicles

Abstract

The present invention provides a control device that can appropriately address problems in actual operation, even when the specifications of the trailer frequently change. [Solution] The PU72 of the steering control device 70 estimates the values ​​of model variables representing the vehicle specifications of the trailer based on the manipulated amount of closed-loop control, where the yaw rate is the controlled variable. The PU102 of the ADASECU100 calculates the allowable steering amount that allows the coupled vehicle to be driven without contacting obstacles, based on the image data Dp, the distance measurement point data Dd, and the estimated values ​​of the model variables. The PU102 performs steering intervention if the front wheel steering angle deviates from the allowable steering amount.

Description

Technical Field

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

Background Art

[0002] For example, Patent Document 1 below describes a control device that performs driving support for a coupled vehicle, such as collision avoidance with an obstacle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in addition to the various specifications of the trailers towed by the tractor, the specifications defining the trailer change depending on the weight of the goods loaded on the trailer and the way the goods are loaded. And even in the same situation, appropriate countermeasures may vary depending on the specifications of the trailer.

Means for Solving the Problems

[0005] Hereinafter, means for solving the above problems and their effects will be described. 1. A control device for a connected vehicle, comprising a tractor and a trailer towed by the tractor, configured to perform model variable estimation processing, environmental data acquisition processing, allowable amount calculation processing, and corrective processing, wherein the model variable estimation processing is a process of estimating the values ​​of model variables, the model variables being variables that define the model of the trailer, the environmental data acquisition processing is a process of acquiring environmental data which is data indicating environmental information in front of the direction of travel of the connected vehicle, the allowable amount calculation processing is a process of calculating an allowable turning control amount based on the values ​​of the model variables as input variables and the environmental data, the allowable turning control amount being a variable indicating the amount of turning that is permissible when the connected vehicle is traveling, and the corrective processing is a process of operating predetermined hardware to deal with the situation when the actual steering deviates from the allowable turning control amount.

[0006] In the above configuration, the values ​​of model variables that define the fluctuating trailer model are estimated. Then, the allowable turning control amount is calculated using the estimated values ​​of the model variables. Therefore, compared to the case where the values ​​of the model variables are default values, the allowable turning control amount can be set to an amount that is more appropriate for the actual trailer specifications. Consequently, problems in actual operation can be dealt with appropriately.

[0007] 2. The control device for a connected vehicle as described in 1 above, wherein the allowable amount calculation process includes an allowable yaw angle calculation process, a current yaw angle acquisition process, an allowable yaw rate calculation process, and an allowable turning control amount conversion process, wherein the allowable yaw angle calculation process is a process that calculates the allowable yaw angle based on the lateral distance to the object in front and the lateral speed of the connected vehicle as input variables, the current yaw angle acquisition process is a process that acquires the yaw angle of the connected vehicle, the allowable yaw rate calculation process is a process that calculates the allowable yaw rate based on the allowable yaw angle and the yaw angle of the connected vehicle as input variables, and the allowable turning control amount conversion process is a process that converts the allowable yaw rate as an input variable into the allowable turning control amount.

[0008] In the above configuration, the allowable yaw angle is calculated based on the lateral distance to the object in front, etc. The difference between the allowable yaw angle and the actual yaw angle is a variable that determines the allowable yaw rate. Therefore, in the above configuration, the allowable yaw rate is calculated based on the above difference. Then, by calculating the allowable turning control amount based on the allowable yaw rate, the amount of turning that can be allowed in relation to a given object can be calculated.

[0009] 3. The control device for the coupled vehicle described in paragraph 2 above, wherein the allowable yaw rate is set to a constant yaw rate at which the yaw angle of the coupled vehicle reaches the allowable yaw angle within a predetermined time. In the above configuration, by setting a predetermined time, the amount of rotation can be set such that the time required to exceed the allowable yaw angle is equal to or greater than the predetermined time.

[0010] 4. A control device for a coupled vehicle according to item 2 or 3 above, wherein the input variable for the allowable yaw angle calculation process includes the yaw rate of the coupled vehicle. In the above configuration, by calculating the allowable yaw angle while taking into account the yaw rate of the connected vehicles, the allowable yaw angle can be calculated while more accurately reflecting the current condition of the connected vehicles compared to when the yaw rate of the connected vehicles is not taken into account.

[0011] 5. A control device for a coupled vehicle according to any one of items 2 to 4 above, wherein the input variable for the allowable yaw angle calculation process includes the longitudinal distance between the coupled vehicle and the object. In the above configuration, by calculating the allowable yaw angle while taking into account the distance in the longitudinal direction, it is possible to calculate the allowable yaw angle while more accurately reflecting the current state of the connected vehicles and objects compared to when the distance in the longitudinal direction is not taken into account.

[0012] 6. The control device for the articulated vehicle according to any one of 2 to 5 above, wherein the object is at least one of two of the following: an obstacle in front and a white line. 7. The control device for a coupled vehicle according to any one of 1 to 6 above, wherein the allowable amount calculation process includes a process performed when the coupled vehicle is being driven by a driver, the predetermined hardware includes a notification device, and the corrective process includes a process of operating the notification device to notify that the driver's steering has deviated from the allowable turning control amount.

[0013] In the above configuration, if the driver's steering input deviates from the permissible turning control amount, the system can notify the driver of this fact, thereby encouraging appropriate driving. 8. The control device for a coupled vehicle as described in 7 above, wherein the notification device includes a device for adjusting the reaction force applied to the operating unit, the operating unit is a member in which the driver inputs an intention to steer, and the countermeasure process includes a process of increasing the reaction force to the operation of the operating unit toward the side that increases the degree of deviation from the allowable turning control amount.

[0014] In the above configuration, by increasing the reaction force to the operation of the control unit in the direction that deviates more from the allowable turning control amount, the driver can easily sense which direction of steering is problematic.

[0015] 9. The control device for a coupled vehicle according to any one of 1 to 8 above, which includes a process for forcibly decelerating the coupled vehicle. In the above configuration, the magnitude of the yaw rate can be forcibly reduced by forcibly decelerating the coupled vehicles when the allowable turning control amount is exceeded. Therefore, it becomes easier to avoid driving that poses safety problems.

[0016] 10. The control device for a coupled vehicle according to any one of 1 to 9 above, which includes an automatic steering process that steers the coupled vehicle so that the actual turning amount of the coupled vehicle does not deviate from the allowable turning control amount, based on the value of the model variable as an input variable and the environmental data.

[0017] In the above configuration, by performing automatic steering processing based on the estimated values ​​of model variables, appropriate steering intervention can be achieved to address problematic driving. 11. A control device for a coupled vehicle according to any one of 1 to 10 above, configured to perform an open-loop operation amount calculation process, a closed-loop operation amount calculation process, and an operation process, wherein the open-loop operation amount calculation process is a process that calculates an open-loop operation amount, which is an operation amount for open-loop control, where a predetermined state amount of the coupled vehicle is a control amount, based on calculations using input variables and model variables; the closed-loop operation amount calculation process is a process that calculates a closed-loop operation amount, which is an operation amount for closed-loop control, where the predetermined state amount is a control amount; the operation process is a process that operates the actuator of the tractor according to both the open-loop operation amount and the closed-loop operation amount; and the model variable estimation process is a process that estimates the value of the model variable based on the closed-loop operation amount as an input variable.

[0018] The open-loop control amount calculation process calculates the open-loop control amount based on calculations using model variables. Therefore, if the values ​​of the model variables deviate from the actual trailer specifications, the controllability of the predetermined control amount by the open-loop control amount decreases. Consequently, when the values ​​of the model variables deviate from the actual trailer specifications, the absolute value of the closed-loop control amount tends to increase. In the above configuration, the values ​​of the model variables can be appropriately corrected by modifying the values ​​of the model variables based on the closed-loop control amount.

[0019] 12. A control device for a connected vehicle according to any one of 1 to 11 above, wherein the model variable is a variable whose value changes depending on at least one of two factors: the arrangement of the trailer's cargo and the mass of the cargo, and the model variable estimation process includes a process of updating the value of the model variable based on the detected value of a physical quantity that changes depending on at least one of the input variables.

[0020] The arrangement of the trailer's cargo and the mass of the cargo are not determined by the trailer's specifications and tend to change frequently. Therefore, in the above configuration, by setting a variable whose value changes depending on at least one of these two as the estimation target, it is possible to accurately grasp the trailer specifications and calculate the allowable turning control amount.

[0021] 13. The control device for a coupled vehicle according to claim 12, wherein the model variable includes at least one of three variables: the center-of-gravity variable of the trailer, the cornering coefficient of the trailer, and the moment of inertia of the trailer in the vertical direction, and the center-of-gravity variable of the trailer is a variable indicating the center of gravity of the trailer.

[0022] 14. A method for controlling a coupled vehicle including execution of each of the processes 1 to 13 above. 15. A control program for a coupled vehicle including commands for causing a computer to execute each of the processes 1 to 13 above.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view showing the configuration of a coupled vehicle according to the first embodiment. [Figure 2] It is a diagram showing the configuration of a control system provided in the coupled vehicle shown in FIG. 1. [Figure 3] It is a block diagram showing the processes executed by the control device provided in the control system shown in FIG. 2. [Figure 4] It is a diagram showing a model of the coupled vehicle according to the same embodiment. [Figure 5] It is a flowchart showing the procedure of the processes executed by the control device provided in the control system shown in FIG. 2. [Figure 6] It is a flowchart showing the procedure of the processes executed by the control device provided in the control system shown in FIG. 2. [Figure 7] It is a flowchart showing the procedure of the processes executed by the control device provided in the control system shown in FIG. 2. [Figure 8] It is a flowchart showing the procedure of the processes executed by the control device provided in the control system shown in FIG. 2. [Figure 9A] A plan view illustrating the process shown in Figure 8. [Figure 9B] A plan view illustrating the process shown in Figure 8. [Figure 10] A time chart illustrating the effects of the above embodiment. [Figure 11] This is a flowchart showing the procedure of processing performed by the control device according to the second embodiment. [Figure 12] This is a flowchart showing the procedure of processing performed by the control device according to the third embodiment. [Figure 13] This is a flowchart showing the procedure of processing performed by the control device according to the fourth embodiment. [Figure 14] This is a flowchart showing the procedure of processing performed by the control device according to the fifth embodiment. [Modes for carrying out the invention]

[0024] <First Embodiment> The first embodiment will be described below with reference to the drawings. "Composition of coupled vehicles" As shown in Figure 1, the articulated vehicle 10 comprises a tractor 20 and a trailer 30. The tractor 20 has front wheels 22 and rear wheels 24. The front wheels 22 include two wheels, 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 in Figure 1, a box-shaped trailer is shown as an example of the trailer 30. The trailer 30 has wheels 32. The wheels 32 include two wheels, the right wheel and the left wheel. Note that the trailer 30 may have a total of four wheels by having left and right front wheels and left and right rear wheels.

[0025] 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.

[0026] Figure 2 shows some of the components of the articulated vehicle 10. As shown in Figure 2, the tractor 20 is equipped with a steering system 50. The steering system 50 includes a steering wheel 52 and front wheels 22 as steering wheels. A reaction force is applied to the steering wheel 52 by a reaction 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 motor 54.

[0027] Meanwhile, the front wheels 22 are powered by the front wheel steering motor 60. The output voltage of the inverter 62 is applied to the terminals of the front wheel steering motor 60. The steering control device 70 comprises a PU 72 and a storage device 74. The PU 72 is a processing unit that executes software processing such as a CPU or GPU. The storage device 74 stores a program that defines the commands for the processing to be executed by the PU 72. The PU 72 controls the object controlled by the steering control device 70 by executing the program stored in the storage device 74.

[0028] The steering control device 70 controls the steering wheel 52. Here, the controlled quantity of the controlled object is the reaction force. The steering control device 70 operates the inverter 56 to control the reaction force. The steering control device 70 also controls the front wheels 22. Here, the controlled quantity of the controlled object is the steering angle of the front wheels 22. The steering angle is the turning angle of the tires. The steering control device 70 operates the inverter 62 to control the steering angle of the front wheels 22.

[0029] The steering control device 70 refers to the steering torque Th detected by the torque sensor 80 for controlling the control amount. The steering torque Th is the torque input to the steering wheel 52. The steering control device 70 also refers to the rotation angle θmh of the reaction motor 54 detected by the rotation angle sensor 82 for controlling the control amount. The steering control device 70 also refers to the rotation angle θmf of the front wheel steering motor 60 detected by the rotation angle sensor 84 for controlling the control amount.

[0030] The tractor 20 is equipped with a drivetrain 86. The drivetrain 86 includes at least one of two components, an internal combustion engine and a rotating electric machine, as a thrust generating device for the vehicle. The tractor 20 is equipped with a braking system 90. The braking system 90 comprises a braking control device 91 and a brake actuator 96. The brake actuator 96 is configured to apply braking force to the front wheels 22 and rear wheels 24 of the tractor 20. The braking control device 91 comprises a PU 92 and a storage device 94. The PU 92 is a processing unit that executes software processing such as a CPU or GPU. The storage device 94 stores a program that defines the commands for the processing to be executed by the PU 92. The PU 92 controls the target of the braking control device 91 by executing the program stored in the storage device 94.

[0031] The braking control device 91 controls the front wheels 22 and the rear wheels 24. The braking control device 91 operates the brake actuator 96 to control the control amount of the controlled objects. The brake actuator 96 includes at least one of two devices: one that slows down the rotation of the wheels by frictional force, and another 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 86.

[0032] The tractor 20 is equipped with ADASECU 100. ADASECU 100 is equipped with PU 102 and storage device 104. PU 102 is a processing unit that executes software processing such as a CPU or GPU. Storage device 104 stores a program that defines the commands for the processing to be executed by PU 102. PU 102 controls the target of ADASECU 100 by executing the program stored in storage device 104. The target of ADASECU 100 is the articulated vehicle 10. Here, the controlled variable is a variable that indicates the behavior of the vehicle. ADASECU 100 operates the steering system 50, the drive system 86, and the braking system 90 to control the controlled variable.

[0033] Furthermore, the drivetrain 86 may include a drive control device that controls an internal combustion engine and a rotating electric machine. In that case, "ADASECU 100 operates the drivetrain 86" means that ADASECU 100 outputs a command signal to the drive control device. Also, "ADASECU 100 operates the braking system 90" means that ADASECU 100 outputs a command signal to the braking control device 91. Also, "ADASECU 100 operates the steering system 50" means that ADASECU 100 outputs a command signal to the steering control device 70.

[0034] The articulated vehicle 10 is equipped with a vehicle speed sensor 112 for detecting the vehicle speed V. The articulated vehicle 10 is equipped with a tractor-side yaw rate sensor 114 for detecting the tractor yaw rate γ. The articulated vehicle 10 is equipped with a trailer-side yaw rate sensor 116 for detecting the trailer yaw rate γt. The articulated vehicle 10 is equipped with a camera 118 for capturing images of the area in front of the vehicle. The articulated vehicle 10 is equipped with a LiDAR 120 that emits laser light and generates distance point data Dd for an object that reflected the laser light based on the reflected light of the laser light. The distance point data Dd is data that links the distance to the object that reflected the laser light with the direction of the laser light irradiation.

[0035] "Control of the steering control system" Figure 3 shows the process performed by the steering control device 70. The process shown in Figure 3 is achieved by the PU 72 repeatedly executing a program stored in the memory device 74, for example, at a predetermined period.

[0036] The target front wheel steering angle setting process M10 sets the target value of the steering angle of the front wheels 22 of the tractor 20, which is the target front wheel steering angle δf*0, based on the steering angle θh and vehicle speed V as input variables. The steering angle θh is the rotation angle of the steering wheel 52. The steering angle θh is calculated by the PU 72 based on the rotation angle θmh as an input variable.

[0037] The target yaw rate setting process M20 sets the target value of the tractor yaw rate γ, which is the target tractor yaw rate γ*, based on the steering angle θh and vehicle speed V as input variables. The target tractor yaw rate γ* is set, for example, to the yaw rate that is expected to occur in the tractor 20 when the tractor 20 is not towing the trailer 30. This setting is intended to assist the coupled vehicle 10 in changing lanes, etc.

[0038] The open-loop control amount calculation process M22 calculates the open-loop control amount Mff, which is the control variable for open-loop control where the tractor yaw rate γ is the controlled variable, based on the target tractor yaw rate γ* as the input variable. The open-loop control amount Mff is the correction amount for the target front wheel steering angle δf*0 required to bring the yaw rate of the tractor 20 closer to the target tractor yaw rate γ*. More specifically, the open-loop control amount calculation process M22 calculates the open-loop control amount Mff using model variables that define the model of the articulated vehicle 10 shown in Figure 4.

[0039] The model shown in Figure 4 has one front wheel C0 corresponding to the pair of front wheels 22 of the tractor 20, and one rear wheel B0 corresponding to the pair of rear wheels 24 of the tractor 20. In other words, a two-wheel model is adopted for the tractor 20. It also has one wheel B1 corresponding to the pair of wheels 32 of the trailer 30. The hitch angle θ is the angle between the line defined by the front wheel C0 and the hitch point C1 and the line defined by the hitch point C1 and the wheel B1. The hitch point C1 corresponds to the axle 42 portion in Figure 1.

[0040] The tractor center of gravity front wheel distance lf is the distance between the front wheel C0 of tractor 20 and the center of gravity of tractor 20. The tractor center of gravity rear wheel distance lr is the distance between the rear wheel B0 of tractor 20 and the center of gravity of tractor 20. The tractor center of gravity hitch point distance lh is the distance between the center of gravity of tractor 20 and the hitch point C1. The trailer center of gravity hitch point distance lft is the distance between the center of gravity of trailer 30 and the hitch point C1. The trailer center of gravity rear wheel distance lrt is the distance between the center of gravity of trailer 30 and wheel B1. The tractor front wheel lateral force Sf is the lateral force acting on the front wheel C0. The tractor rear wheel lateral force Sr is the lateral force acting on the rear wheel B0. In this model, the steering angle of the front wheel C0 is set to the front wheel steering angle δf. Also, the steering angle of the rear wheel B0 is set to the rear wheel steering angle δr. However, in this embodiment, the rear wheel steering angle δr is always considered to be 0. Also, in this model, the longitudinal movement speed of the center of gravity of the tractor 20 is considered to be the vehicle speed V of the coupled vehicle 10. Tractor lateral speed vy indicates the lateral speed of the center of gravity of the tractor 20. Trailer lateral speed vyt indicates the lateral speed of the center of gravity of the trailer 30. Tractor crosswind force W indicates the force exerted on the tractor 20 by the lateral wind. Trailer crosswind force Wt indicates the force exerted on the trailer 30 by the lateral wind.

[0041] The open-loop manipulated variable calculation process M22 calculates the open-loop manipulated variable Mff based on the following equations of motion for the model shown in Figure 4. m·V·(dβ / dt+γ)=Sf+Sr-F+W …(c1) Iz·dγ / dt=lf·Sf-lr·Sr+lh·F+lw·W+Mz …(c2) mt·V·(dβt / dt+γt)=Sfr+Ft+Wt …(c3) Izt·dγt / dt=lft·Ft-lrt·Srt+lwt·Wt+Mzt …(c4) Sf=Cf·{δf-(vy+lf·γ) / V} …(c5) Sγ=Cr·{δr-(vy-lr·γ) / V} …(c6) Srt=-Crt·(vyt-lrt·γt) / V …(c7) However, the lateral slip angle β is the lateral slip angle of the tractor 20. The lateral slip angle βt is the lateral slip angle of the trailer 30. The tractor hitch force F is the force applied to the tractor 20 at the hitch point C1. The trailer hitch force Ft is the force applied to the trailer 30 at the hitch point C1. Furthermore, the tractor moment of inertia Iz is the moment of inertia of the tractor 20 in the vertical direction. Furthermore, the trailer moment of inertia Izt is the moment of inertia of the trailer 30 in the vertical direction. Note that the vertical direction is the direction perpendicular to the front, rear, left, and right directions of the connected vehicle 10. Furthermore, the tractor brake moment Mz is the moment generated in the tractor 20 by the brake actuator 96. Furthermore, the trailer brake moment Mzt is the moment applied to the trailer 30 when the trailer 30 is equipped with a brake actuator. However, in this embodiment, the trailer brake moment Mzt is zero. Furthermore, the tractor crosswind center lw is the distance between the center where the crosswind acts on the tractor 20 and the center of gravity of the tractor 20. The trailer crosswind center lwt is the distance between the center where the crosswind acts on the trailer 30 and the center of gravity of the trailer 30. The tractor front wheel cornering coefficient Cf is the cornering coefficient of the front wheel C0 of the tractor 20. The tractor rear wheel cornering coefficient Cr is the cornering coefficient of the rear wheel B0 of the tractor 20. The trailer cornering coefficient Crt is the cornering coefficient of the wheel B1 of the trailer.

[0042] Equation (c1) above represents the lateral motion of the tractor 20. Equation (c2) above represents the rotational motion of the tractor 20. Equation (c3) above represents the lateral motion of the trailer 30. Equation (c4) above represents the rotational motion of the trailer 30.

[0043] The open-loop maneuver calculation process M22 includes the process of substituting the target tractor yaw rate γ* into the tractor yaw rate γ. The open-loop maneuver calculation process M22 also includes the process of substituting the value obtained by subtracting the target front wheel steering angle δf*0 from the front wheel steering angle δf, which is obtained by algebraically solving the system of equations (c1) to (c7) above, into the open-loop maneuver Mff. The unknowns in the system of equations (c1) to (c7) above are the front wheel steering angle δf, the tractor front wheel lateral force Sf, the tractor rear wheel lateral force Sr, the slip angles β, βt, the tractor hitch force F, and the trailer hitch force Ft. Furthermore, when calculating the front wheel steering angle δf, terms in the simultaneous equations (c1) to (c7) above that include the tractor crosswind center lw, trailer crosswind center lwt, tractor crosswind force W, and trailer crosswind force Wt may be considered zero. Alternatively, for example, the tractor crosswind center lw, trailer crosswind center lwt, tractor crosswind force W, and trailer crosswind force Wt may be estimated by obtaining wind speed, wind direction, etc., indicated by weather information from outside the connected vehicle 10. In addition, the distance between the rear wheels of the tractor's center of gravity lr, the distance between the hitch points of the tractor's center of gravity lh, the distance between the hitch points of the trailer's center of gravity lft, and the distance between the rear wheels of the trailer's center of gravity lrt are stored in the memory device 74 beforehand. Also, the tractor moment of inertia Iz and the trailer moment of inertia Izt are stored in the memory device 74. PU72 uses the detected value as the trailer yaw rate γt in the system of equations (c1) to (c7) above. Furthermore, PU72 calculates the tractor lateral speed vy and trailer lateral speed vyt based on the vehicle speed V and the previously estimated values ​​of the slip angles β and βt.

[0044] Returning to Figure 3, the deviation calculation process M24 calculates the deviation Δγ, which is the value obtained by subtracting the tractor yaw rate γ from the target tractor yaw rate γ*. The closed-loop manipulated variable calculation process M26 calculates the closed-loop manipulated variable Mfb, which is the manipulated variable for closed-loop control where the tractor yaw rate γ is the controlled variable and the target tractor yaw rate γ* is the target value of the controlled variable, based on the deviation Δγ as the input variable.

[0045] The manipulated variable calculation process M28 is a process that substitutes the sum of the open-loop manipulated variable Mff and the closed-loop manipulated variable Mfb into the correction amount Δf. The steering angle correction process M30 is a process that adds a correction amount Δf to the target front wheel steering angle δf*0 and substitutes that value into the target front wheel steering angle δf*.

[0046] The control signal generation process M32 generates the control signal MSf for the inverter 62 based on the target front wheel steering angle δf* as an input variable. The control signal MSf controls the torque of the front wheel steering motor 60 so that the front wheel steering angle δf approaches the target front wheel steering angle δf*.

[0047] "Regarding the acquisition of model variables" The trailer 30 towed by the tractor 20 can be freely changed by the driver. Therefore, the specifications of the trailer 30 may change. In this embodiment, model information regarding the trailer 30 is obtained by input from outside the connected vehicle 10.

[0048] Figure 5 shows the procedure for obtaining the values ​​of the model variables of the trailer 30. The series of processes shown in Figure 5 are realized by the PU 102 repeatedly executing a program stored in the memory device 104 of the ADASECU 100, for example, at a predetermined period. In the following, the step number of each process is represented by a number preceded by "S".

[0049] In the series of processes shown in Figure 5, PU102 first determines whether or not values ​​for the model variables defining the trailer 30 have been input by an input operation to the user interface 130 shown in Figure 2 (S10). In the process of S10, as an example, the model variables are the trailer weight mt and variables indicating the center of gravity information of the trailer 30. The variables indicating the center of gravity information of the trailer 30 are the distance between the trailer center of gravity hitch points lft and the distance between the trailer center of gravity rear wheels lrt.

[0050] If PU102 determines that a value for a model variable has been input (S10: YES), it stores the trailer weight mt, the distance between the trailer's center of gravity hitch points lft, and the distance between the trailer's center of gravity rear wheels lrt in the storage device 104 (S12).

[0051] Furthermore, PU102 terminates the series of processes shown in Figure 5 if it completes the process in S12 or if it makes a negative determination in the process in S10. If the process in S12 has been completed, PU72 obtains the trailer weight mt, the distance between the trailer center of gravity hitch points lft, and the distance between the trailer center of gravity rear wheels lrt from ADASECU100 stored in the storage device 104 and stores them in the storage device 74. On the other hand, if the process in S12 has not been completed, the open-loop operation amount calculation process M22 includes the process of reading default values ​​that have been previously stored in the storage device 74 as the trailer weight mt, the distance between the trailer center of gravity hitch points lft, and the distance between the trailer center of gravity rear wheels lrt.

[0052] "Update of Trailer Cornering Coefficient" The open-loop operation amount calculation process M22 includes a process to calculate the open-loop operation amount Mff using a default value stored in the storage device 74 as the trailer cornering coefficient Crt. The trailer cornering coefficient Crt changes not only due to the specifications of the trailer 30 but also due to the aging of the trailer's wheels 32. Therefore, in this embodiment, the trailer cornering coefficient Crt used by the open-loop operation amount calculation process M22 is updated by estimating the trailer cornering coefficient Crt.

[0053] Figure 6 shows the procedure for updating the trailer cornering coefficient Crt. The series of processes shown in Figure 6 are realized by the PU 72 repeatedly executing a program stored in the memory device 74, for example, at a predetermined period.

[0054] In the series of processes shown in Figure 6, the PU72 first determines whether the tractor 20 is towing the trailer 30 (S20). In other words, the PU72 determines whether the trailer 30 is connected to the rear of the tractor 20 via the ball joint 40. The process in S20 may also be a process in which the PU72 determines whether there is a history in the storage device 74 of the driver inputting information that the trailer 30 has been connected to the tractor 20 through an input operation to the user interface 130. Alternatively, the process in S20 may be a process that is executed using an image captured by a camera installed at the rear of the tractor 20.

[0055] If PU72 determines that the trailer is in a towing state (S20: YES), it determines whether or not there is cargo loaded on the trailer 30 (S22). The process in S22 may be, for example, a process in which PU72 determines whether or not there is a history in the storage device 74 of the driver inputting information that cargo has been loaded onto the trailer 30 through an input operation to the user interface 130. Alternatively, the process in S22 may be a process that is performed using an image captured by a camera installed at the rear of the tractor 20.

[0056] If PU72 determines that there is no cargo loaded (S22:YES), it determines whether the connected vehicle 10 is in motion (S24). If PU72 determines that the vehicle is in motion (S24:YES), it determines whether the absolute value of the closed-loop operation amount Mfb is greater than or equal to the threshold Mfbth (S26). This process determines whether the value of the trailer cornering coefficient Crt used by the open-loop operation amount calculation process M22 may deviate significantly from the actual value. In other words, if the magnitude of the closed-loop operation amount Mfb is greater than a predetermined value, the open-loop operation amount Mff calculated by the open-loop operation amount calculation process M22 may deviate significantly from the appropriate value. On the other hand, the open-loop operation amount calculation process M22 calculates the open-loop operation amount Mff using the trailer cornering coefficient Crt. Therefore, if the magnitude of the closed-loop operation amount Mfb is greater than a predetermined value, the value of the trailer cornering coefficient Crt may deviate significantly from the actual value.

[0057] If PU72 determines that the absolute value of the closed-loop manipulated variable Mfb is greater than or equal to the threshold Mfbth (S26: YES), it obtains the closed-loop manipulated variable Mfb (S28). Then, PU28 calculates the correction amount ΔCrt for the trailer cornering coefficient Crt based on the closed-loop manipulated variable Mfb as an input variable (S30). The correction amount ΔCrt is a value used to correct the trailer cornering coefficient Crt so as to reduce the magnitude of the closed-loop manipulated variable Mfb.

[0058] The process in S30 may be a process in which the correction amount ΔCrt is calculated by the PU 72 using a map calculation while the map data is stored in the storage device 74. Here, the map data is data in which the closed-loop manipulated variable Mfb is the input variable and the correction amount ΔCrt is the output variable. Alternatively, the process in S30 may be a process in which the correction amount ΔCrt is calculated according to the value of an output variable such as a proportional controller in which the closed-loop manipulated variable Mfb is the input variable.

[0059] Furthermore, the process in S30 may include vehicle speed V, etc., in addition to the closed-loop manipulated variable Mfb, as input variables. In that case, the process in S28 should include the process of acquiring vehicle speed V, etc. Also, if a map calculation is performed in the process in S30, the map data should be data in which the closed-loop manipulated variable Mfb and vehicle speed V, etc., are input variables and the correction amount ΔCrt is the output variable. Also, if the correction amount ΔCrt is calculated using a proportional controller, etc., in the process in S30, a process may be constructed to change the proportional gain according to vehicle speed V, etc.

[0060] 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.

[0061] PU72 performs a guard process to ensure that the magnitude of the correction amount ΔCrt is less than or equal to the upper limit (S32). Then, PU72 adds the guarded correction amount ΔCrt to the trailer cornering coefficient Crt and substitutes the result into the trailer cornering coefficient Crt (S34). PU72 stores the updated trailer cornering coefficient Crt in the memory device 74 and transmits it to ADASECU100.

[0062] Furthermore, PU72 terminates the series of processes shown in Figure 6 when it completes the process in S34, or when it makes a negative determination in the processes of S20 to S26. "Update of trailer moment of inertia and center of gravity variables" The open-loop maneuver amount calculation process M22 includes a process for calculating the open-loop maneuver amount Mff using data indicating the trailer moment of inertia Izt and the center of gravity information of the trailer 30. The trailer moment of inertia Izt and the center of gravity information of the trailer 30 change not only depending on the specifications of the trailer 30 but also on the state of the cargo loaded onto the trailer 30. Therefore, in this embodiment, the data indicating the trailer moment of inertia Izt and the center of gravity information of the trailer 30 used by the open-loop maneuver amount calculation process M22 is updated by estimating the trailer moment of inertia Izt and the center of gravity information of the trailer 30.

[0063] Figure 7 shows the procedure for updating the data indicating the trailer moment of inertia Izt and the center of gravity information of the trailer 30. The series of processes shown in Figure 7 are realized by the PU 72 repeatedly executing a program stored in the memory device 74, for example, at a predetermined period.

[0064] In the series of processes shown in Figure 7, PU72 first determines whether the tractor 20 is towing the trailer 30 (S40), similar to the process in S20 of Figure 6. If PU72 determines that the trailer 30 is towing (S40: YES), it determines whether there is cargo loaded on the trailer 30 by the same process as in S22 of Figure 6 (S42). If PU72 determines that there is cargo loaded (S42: YES), it determines whether the combined vehicle 10 is in motion (S44). If PU72 determines that the vehicle is in motion (S44: YES), it determines whether the absolute value of the closed-loop operation amount Mfb is greater than or equal to the threshold Mfbth (S46). This process determines whether at least one of the values ​​of the trailer moment of inertia Izt and the data indicating the center of gravity information of the trailer 30 deviates significantly from the actual value.

[0065] If PU72 determines that the absolute value of the closed-loop manipulated amount Mfb is greater than or equal to the threshold Mfbth (S46: YES), it obtains the closed-loop manipulated amount Mfb (S48). Then, based on the closed-loop manipulated amount Mfb as an input variable, PU72 calculates the correction amount ΔIz for the trailer moment of inertia Izt and the correction amount for the data indicating the center of gravity information of the trailer 30 (S50). The correction amount ΔIz is a value used to correct the trailer moment of inertia Izt so as to reduce the magnitude of the closed-loop manipulated amount Mfb. The correction amount ΔIft for the data indicating the center of gravity information is a value used to correct the distance lft between the trailer center of gravity hitch points so as to reduce the magnitude of the closed-loop manipulated amount Mfb. The correction amount ΔIrt for the data indicating the center of gravity information is a value used to correct the distance lrt between the trailer center of gravity and the rear wheels so as to reduce the magnitude of the closed-loop manipulated amount Mfb.

[0066] The process in S50 may be a process in which the correction amounts ΔIft, ΔIft, and ΔIrt are calculated by mapping the map data stored in the memory device 74 using the PU 72. Here, the map data is data in which the closed-loop manipulated variable Mfb is the input variable and the correction amounts ΔIft, ΔIft, and ΔIrt are the output variables. Alternatively, the process in S50 may be a process in which the correction amounts ΔIft, ΔIft, and ΔIrt are calculated according to the value of an output variable such as a proportional controller in which the closed-loop manipulated variable Mfb is the input variable.

[0067] Furthermore, the processing in S50 may include vehicle speed V, etc., in addition to the closed-loop manipulated variable Mfb, as input variables. In that case, the processing in S48 should include the process of acquiring vehicle speed V, etc. Also, when performing a map calculation in the processing of S50, the map data should be data in which the closed-loop manipulated variable Mfb and vehicle speed V, etc. are input variables and the correction amounts ΔIft, ΔIft, ΔIrt are output variables. Also, when the correction amounts ΔIft, ΔIft, ΔIrt are calculated using a proportional controller, etc., a process may be constructed in which the proportional gain is changed according to vehicle speed V, etc.

[0068] PU72 applies a guarding process to ensure that the magnitudes of the correction amounts ΔIft, ΔIft, and ΔIrt are below the upper limit (S52). Then PU72 updates the values ​​indicating the trailer moment of inertia Izt and the center of gravity information of the trailer 30 (S54). Specifically, PU72 substitutes the value obtained by adding the guarded correction amount ΔIzt to the trailer moment of inertia Izt. Also, PU72 substitutes the value obtained by adding the guarded correction amount ΔIft to the trailer center of gravity hitch distance lft. Also, PU72 substitutes the value obtained by adding the guarded correction amount ΔIrt to the trailer center of gravity rear wheel distance lrt. The PU72 then stores the updated trailer moment of inertia Izt, the distance between the trailer center of gravity hitch points lft, and the distance between the trailer center of gravity rear wheels lrt in the storage device 74 and transmits them to the ADASECU100.

[0069] Furthermore, PU72 terminates the series of processes shown in Figure 7 when it completes the process in S54, or when it makes a negative determination in the processes from S40 to S46. "Danger Notice" Figure 8 shows the procedure for the hazard prediction process according to this embodiment. The process shown in Figure 8 is achieved by the PU102 of ADASECU100 repeatedly executing a program stored in the storage device 104.

[0070] In the series of processes shown in Figure 8, the PU 102 first acquires image data Dp from the camera 118 and distance measurement point data Dd output by the LIDAR 120 (S60). Next, the PU 102 identifies an object in front of the coupled vehicle 10 in the direction of travel based on the image data Dp and distance measurement point data Dd (S62). Here, the object is something that should be taken into consideration for the safe operation of the coupled vehicle 10. One example of an object is an obstacle that obstructs the movement of the coupled vehicle 10. Another example of an object is a white line.

[0071] PU102 calculates the horizontal distance dy, which is the horizontal distance to the object (S64). Figure 9A illustrates the lateral distance dy when the object is an obstacle 140.

[0072] Figure 9B illustrates the horizontal distance dy when the object is the white line 142. Returning to Figure 8, PU102 obtains the tractor lateral speed vy, tractor yaw rate γ, and yaw angle φ (S66). The tractor lateral speed vy is calculated by PU102. PU102 may calculate the tractor lateral speed vy based, for example, on the steering angle of the front wheels 22 and the vehicle speed V as input variables. Alternatively, for example, PU102 may calculate the tractor lateral speed vy based on image data Dp and distance measurement point data Dd as input variables. The yaw angle φ is calculated by PU102. PU102 may calculate the yaw angle φ based, for example, on the time integral of the tractor yaw rate γ as an input variable. Alternatively, for example, PU102 may calculate the yaw angle φ based on the steering angle of the front wheels 22 and the vehicle speed V as input variables.

[0073] PU102 calculates the allowable yaw angle φp based on the input variables: lateral distance dy, tractor lateral speed vy, and tractor yaw rate γ (S68). The allowable yaw angle φp indicates the upper limit of the yaw angle φ that is allowed for the safe operation of the coupled vehicle 10. PU120 may change the allowable yaw angle φp according to the lateral distance dy, for example, under the condition that the size of the allowable yaw angle φp when the lateral distance dy is small is less than or equal to the size of the allowable yaw angle φp when the lateral distance dy is large. Alternatively, PU102 may change the allowable yaw angle φp according to the tractor lateral speed vy, under the condition that the size of the allowable yaw angle φp when the tractor lateral speed vy is small is less than or equal to the size of the allowable yaw angle φp when the tractor lateral speed vy is large.

[0074] Furthermore, in statements such as "change B according to A while satisfying the condition that B when A is large is greater than or equal to B when A is small," "when A is large" and "when A is small" refer to the relative magnitude relationship when comparing the two. For example, "when A is large" corresponds to "when A is the first value," and "when A is small" corresponds to "when A is the second value which is smaller than the first value." Also, the above statement means that, depending on the settings of the first and second values, B when A is the first value may be larger than B when A is the second value. Also, the above statement means that change B according to A so that A when B is large is larger than A when B is small.

[0075] The processing in S68 may also be a process in which the PU102 performs a map calculation to determine the allowable yaw angle φp while the map data is stored in the memory device 104. Here, the map data is data in which the lateral distance dy, tractor lateral speed vy, and tractor yaw rate γ are input variables and the allowable yaw angle φp is the output variable.

[0076] Next, PU102 calculates the allowable yaw rate γp (S70). The allowable yaw rate γp is the lower limit of the magnitude of the yaw rate at which the actual yaw angle φ reaches the allowable yaw angle φp within a predetermined time ΔT. Here, using the predetermined time ΔT, the allowable yaw rate γp may be, for example, "(φp-φ) / ΔT".

[0077] Next, PU102 calculates the front wheel steering angle threshold δfp using the above equations (c1) to (c7) (S72). The front wheel steering angle threshold δfp is the upper limit of the front wheel steering angle δf required to keep the yaw rate below the allowable yaw rate γp. PU102 takes the front wheel steering angle δf as an unknown in the above equations (c1) to (c7) and finds the solution as the front wheel steering angle threshold δfp. In the above equations (c1) to (c7), PU102 substitutes the allowable yaw rate γp for the tractor yaw rate γ and the trailer yaw rate γt. In this process, the trailer cornering coefficient Crt, trailer moment of inertia Izt, trailer center of gravity hitch distance lft, and trailer center of gravity rear wheel distance lrt are the values ​​updated by the processes described in Figures 4 and 7.

[0078] PU74 determines whether the magnitude of the front wheel steering angle δf exceeds the magnitude of the front wheel steering angle threshold δfp (S74). This process determines whether it may become difficult to safely drive the coupled vehicle 10. That is, for example, in the case illustrated in Figure 9A, the process of S74 determines whether there is a risk of contact with the obstacle 140 in the near future. Also, for example, in the case illustrated in Figure 9B, the process of S74 determines whether there is a risk of crossing the white line 142 in the near future. Note that the near future may be, for example, a period within a predetermined time ΔT.

[0079] If the PU102 determines that the magnitude of the front wheel steering angle δf exceeds the magnitude of the front wheel steering angle threshold δfp (S74: YES), it increases the magnitude of the reaction torque Tr that opposes turning the steering wheel 52 in the direction that increases the magnitude of the front wheel steering angle δf (S76). Specifically, the PU102 sends a command signal to the steering control device 70 to increase the magnitude of the reaction torque Tr. The process in S74 is a process to warn the driver not to turn the steering wheel in a way that increases the magnitude of the steering angle θh.

[0080] Furthermore, when PU102 completes the process in S76, or when it makes a negative determination in the process in S74, it temporarily terminates the series of processes shown in Figure 8. "The operation and effects of this embodiment" The upper part of Figure 10 shows the change in steering angle θh as the driver operates the steering wheel 52. The lower part of Figure 10 shows the change in the amount of lateral movement of the coupled vehicle 10 in accordance with the steering angle θh. The dashed-dot line and the double-dashed-dot line in Figure 10 represent cases where the cargo state of the trailer 30 is different, respectively. As shown in Figure 10, if the vehicle specifications of the trailer 30, such as the cargo state, are different, the lateral displacement of the coupled vehicle 10 will be different even if the change in steering angle θh is the same. Therefore, the prediction accuracy of whether or not the coupled vehicle 10 can be driven safely depends on the accuracy of the vehicle specifications of the trailer 30 that the PU 102 can use.

[0081] Therefore, PU102 obtained estimated values ​​from PU72 for the trailer cornering coefficient Crt, trailer moment of inertia Izt, trailer center of gravity hitch distance lft, and trailer center of gravity rear wheel distance lrt. Then, PU102 calculated the front wheel steering angle threshold δfp based on the estimated and updated values ​​of these vehicle parameters. This makes it possible to predict with high accuracy whether or not the coupled vehicle 10 is likely to be unable to travel safely.

[0082] According to the embodiment described above, the following effects and benefits can be obtained. (1) PU102 calculated the allowable yaw angle φp based on input variables such as lateral distance dy, tractor lateral speed vy, and tractor yaw rate γ. This allows the allowable yaw angle φp to be calculated while accurately reflecting the relationship between the coupled vehicle 10 and the object.

[0083] (2) PU102 calculated the allowable yaw rate γp based on the difference between the allowable yaw angle φp as an input variable and the actual yaw angle φ. This allows setting an upper limit for the magnitude of the yaw rate so that the yaw angle φ does not immediately exceed the magnitude of the allowable yaw angle φp.

[0084] (3) PU102 converted the allowable yaw rate γp into a front wheel steering angle threshold δfp. This allows setting the allowable amount of the front wheel steering angle δf. (4) PU72 updated the trailer cornering coefficient Crt based on the closed-loop control amount Mfb when the trailer 30 is unloaded. When the trailer 30 is loaded, the trailer cornering coefficient Crt is not the only model variable that affects the controllability of the tractor yaw rate γ and whose value is prone to fluctuation. When the trailer 30 is loaded, the model variables that affect the controllability of the tractor yaw rate γ and whose value is prone to fluctuation include the trailer moment of inertia Izt and a variable indicating the center of gravity of the trailer 30. Therefore, by using the closed-loop control amount Mfb when the trailer 30 is unloaded, the trailer cornering coefficient Crt can be estimated with higher accuracy compared to when using the closed-loop control amount Mfb when the trailer is loaded.

[0085] (5) PU72 updated the trailer moment of inertia Izt and the value indicating the center of gravity of the trailer 30 based on the closed-loop operation amount Mfb when the trailer 30 is loaded with cargo. The trailer moment of inertia Izt and the value indicating the center of gravity of the trailer 30 are prone to fluctuations depending on how the cargo is loaded onto the trailer 30. Therefore, by using the closed-loop operation amount Mfb when the trailer 30 is loaded with cargo, it is possible to obtain the trailer moment of inertia Izt and the value indicating the center of gravity of the trailer 30 according to the state of the cargo.

[0086] <Second Embodiment> The second embodiment will be described below, focusing on the differences from the first embodiment, with reference to the drawings.

[0087] In the above embodiment, if there was a risk that the coupled vehicle 10 could not be driven safely, the PU 102 warned the driver. In contrast, in this embodiment, if there is a risk that the coupled vehicle 10 could not be driven safely, the PU 102 intervenes in the driving of the coupled vehicle 10.

[0088] Figure 11 shows the procedure for the intervention described above. The process shown in Figure 11 is achieved by the PU102 of ADASECU100 repeatedly executing the program stored in the memory device 104. For convenience, the same step numbers are used in Figure 11 for processes corresponding to those shown in Figure 8.

[0089] In the series of processes shown in Figure 11, if the PU 102 makes a positive determination in process S74, it forcibly decelerates the coupled vehicle 10 by operating at least one of the drive system 86 and the braking system 90 (S76a). If the PU 102 completes process S76a, it terminates the series of processes shown in Figure 11.

[0090] By slowing down the coupled vehicle 10 in this way, the driver can more easily steer to avoid obstacles 140 or to avoid crossing the white line 142, compared to when the vehicle is not slowed down.

[0091] <Third Embodiment> The third embodiment will be described below, focusing on the differences from the second embodiment, with reference to the drawings.

[0092] In this embodiment, the degree of intervention in the operation of the coupled vehicle 10 is increased even further than in the second embodiment described above. Figure 12 shows the procedure for the intervention described above. The process shown in Figure 12 is achieved by the PU102 of ADASECU100 repeatedly executing the program stored in the memory device 104. For convenience, the same step numbers are used in Figure 12 for processes corresponding to those shown in Figure 8.

[0093] In the series of processes shown in Figure 12, if the PU102 makes a positive determination in process S74, it performs steering intervention by operating the steering system 50 so that the front wheel steering angle δf is appropriate for the state of the trailer 30 (S76b). Incidentally, the absolute value of the front wheel steering angle δf appropriate for the state of the trailer 30 is set to be less than or equal to the front wheel steering angle threshold δfp.

[0094] Furthermore, once the processing in S76b is complete, PU102 will terminate the series of processes shown in Figure 12. The S76b process described above utilizes values ​​updated by the processes described in Figures 4 and 7 as the trailer cornering coefficient Crt, trailer moment of inertia Izt, trailer center of gravity hitch distance lft, and trailer center of gravity rear wheel distance lrt. Therefore, it is possible to achieve appropriate steering intervention based on the actual vehicle specifications of the trailer 30.

[0095] <Fourth Embodiment> The fourth embodiment will be described below, focusing on the differences from the second embodiment, with reference to the drawings.

[0096] In the second embodiment described above, it was determined whether or not the coupled vehicle 10 was in danger of not being able to travel safely based on the front wheel steering angle δf as an input variable. In this embodiment, this input variable is changed.

[0097] Figure 13 shows the procedure for the intervention described above. The process shown in Figure 13 is achieved by the PU102 of ADASECU100 repeatedly executing the program stored in the memory device 104. For convenience, the same step numbers are used in Figure 13 for processes corresponding to the process shown in Figure 8.

[0098] In the series of processes shown in Figure 13, after completing the process in S70, PU102 calculates the allowable tractor brake moment Mzp using the above equations (c1) to (c7) (S72a). The allowable tractor brake moment Mzp is the upper limit of the magnitude of the tractor brake moment Mz required to keep the magnitude of the yaw rate below the magnitude of the allowable yaw rate γp. PU102 takes the tractor brake moment Mz as an unknown in the above equations (c1) to (c7) and finds the solution as the allowable tractor brake moment Mzp. In the above equations (c1) to (c7), PU102 substitutes the allowable yaw rate γp for the tractor yaw rate γ and the trailer yaw rate γt. Also, PU102 substitutes the actual front wheel steering angle δf for the front wheel steering angle δf in the above equations (c1) to (c7). Furthermore, PU102 uses the updated values ​​in Figures 4 and 7 as the trailer cornering coefficient Crt, trailer moment of inertia Izt, trailer center of gravity hitch distance lft, and trailer center of gravity rear wheel distance lrt in equations (c1) to (c7) above.

[0099] Then, PU102 determines whether the magnitude of the tractor brake moment Mz exceeds the magnitude of the allowable tractor brake moment Mzp (S74a). This process determines whether or not it may become difficult to safely operate the coupled vehicle 10.

[0100] If PU102 determines that the process in S74a is positive, it proceeds to the process in S76a. <Fifth Embodiment> The fifth embodiment will be described below, focusing on the differences from the third embodiment, with reference to the drawings.

[0101] The process in S74 described above is a determination process that is effective when an object exists to the side in front of the coupled vehicle 10. In contrast, in this embodiment, a process is executed that is effective when an obstacle exists in front of the coupled vehicle 10 in the direction of travel.

[0102] Figure 14 shows the procedure for the intervention described above. The process shown in Figure 14 is achieved by the PU102 of ADASECU100 repeatedly executing the program stored in the memory device 104. For convenience, the same step numbers are used in Figure 14 for the processes corresponding to the process shown in Figure 8.

[0103] In the series of processes shown in Figure 14, if PU102 completes the process in S64, it obtains the tractor lateral speed vy, tractor yaw rate γ, yaw angle φ, and longitudinal distance L (S66a). The longitudinal distance L is the longitudinal distance between the coupled vehicle 10 and the obstacle 140. Then, PU72 calculates the allowable yaw angle φp based on the lateral distance dy, tractor lateral speed vy, tractor yaw rate γ, and longitudinal distance L (S68a). The allowable yaw angle φp is the lower limit of the magnitude of the yaw angle φ required for the coupled vehicle 10 to travel safely. PU120 may change the allowable yaw angle φp according to the lateral distance dy, for example, under the condition that the magnitude of the allowable yaw angle φp when the longitudinal distance L is small is greater than or equal to the magnitude of the allowable yaw angle φp when the longitudinal distance L is large. Alternatively, PU120 may change the allowable yaw angle φp according to the lateral distance dy, for example, under the condition that the magnitude of the allowable yaw angle φp when the lateral distance dy is small is greater than or equal to the magnitude of the allowable yaw angle φp when the lateral distance dy is large. Furthermore, PU102 may change the allowable yaw angle φp according to the tractor lateral speed vy, provided that the allowable yaw angle φp when the tractor lateral speed vy is small is greater than or equal to the allowable yaw angle φp when the tractor lateral speed vy is large.

[0104] The process in S68a may be a process in which the PU102 performs a map calculation on the map data stored in the memory device 104. Here, the map data is data in which the lateral distance dy, tractor lateral speed vy, tractor yaw rate γ, and longitudinal distance L are input variables and the allowable yaw angle φp is the output variable. When the PU102 completes the process in S68a, it proceeds to the process in S70.

[0105] Furthermore, if PU102 completes the process in S70, it calculates the front wheel steering angle threshold δfp (S72b). The front wheel steering angle threshold δfp calculated by the process in S72b is the lower limit of the magnitude of the front wheel steering angle δf required to drive the connected vehicle 10 without contacting an obstacle in front. If PU102 completes the process in S72a, it determines whether the magnitude of the front wheel steering angle δf is smaller than the magnitude of the front wheel steering angle threshold δfp (S74b). The process in S74b is to determine whether there is a risk of the connected vehicle 10 contacting an obstacle in front. If PU102 determines that the magnitude of the front wheel steering angle δf is smaller than the magnitude of the front wheel steering angle threshold δfp (S74b: YES), it proceeds to S76b.

[0106] <Correspondence> The correspondence between the matters in the above embodiment and the matters described in the "Means for Solving the Problems" section is as follows. Below, the correspondence is shown for each number of the solution means described in the "Means for Solving the Problems" section. [1] The model variable estimation process corresponds to the processes in S26 to S34 and S46 to S54. The environmental data acquisition process corresponds to the process in S60. The environmental information corresponds to information regarding obstacles 140 and white lines 142 in front of the vehicle. The environmental data corresponds to image data Dp and distance measurement point data Dd. The tolerance calculation process corresponds to the processes in S60 to S72 in Figures 8, 11 and 12, the processes in S60 to S70 and S72a in Figure 13, and the processes in S60 to S64, S66a, S68a, S70 and S72b in Figure 14. The permissible turning control amount corresponds to the front wheel steering angle δf having an absolute value less than or equal to the front wheel steering angle threshold δfp in Figures 8, 11, and 12. The permissible turning control amount corresponds to the front wheel steering angle δf having an absolute value greater than or equal to the front wheel steering angle threshold δfp in Figure 14. The permissible turning control amount corresponds to the tractor brake moment Mz having an absolute value less than or equal to the moment threshold Mzp in Figure 13. The corrective processing corresponds to the processing of S76, S76a, and S76b. The model variables correspond to the trailer cornering coefficient Crt, the trailer moment of inertia Izt, the distance between the trailer center of gravity hitch points lft, and the distance between the trailer center of gravity rear wheels lrt. The predetermined hardware for processing S76 corresponds to the inverter 56. The predetermined hardware for S76a corresponds to the drive system 86 and the braking system 90. The predetermined hardware for S76b corresponds to the inverter 62. [2,3] The permissible yaw angle calculation processing corresponds to the processing of S68. Currently, the yaw angle acquisition process corresponds to the process in S66. The allowable yaw rate calculation process corresponds to the process in S70. The allowable turning control amount conversion process corresponds to the processes in S72, S72a, and S72b. The objects correspond to obstacle 140 and white line 142. [4] This corresponds to the inclusion of tractor yaw rate γ in the input variables of the process in S68. [5] This corresponds to the inclusion of front-rear distance L in the input variables of the process in S68a. [6] This corresponds to obstacle 140 shown in Figure 9A and white line 142 shown in Figure 9B. [7,8] The notification device corresponds to inverter 56. [9] The countermeasure process corresponds to the process in S76a.

[10] The handling process corresponds to the process in S76b.

[11] The open-loop manipulator calculation process corresponds to the open-loop manipulator calculation process M22. The closed-loop manipulator calculation process corresponds to the closed-loop manipulator calculation process M26. The operation process corresponds to the operation signal generation process M32.

[12] The model variables correspond to the trailer moment of inertia Izt, the distance between the trailer center of gravity hitch points lft, and the distance between the trailer center of gravity rear wheels lrt. The detected value of the physical quantity corresponds to the tractor yaw rate γ.

[13] The trailer center of gravity variables correspond to the distance between the trailer center of gravity hitch points lft and the distance between the trailer center of gravity rear wheels lrt.

[0107] <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.

[0108] "Regarding the permissible amount of turning control" The permissible turning control amount is not limited to just one of the following: a quantity relating to the front wheel steering angle δf of the tractor 20, or a quantity relating to the tractor brake moment Mz. The permissible turning control amount may be, for example, both of these quantities. Alternatively, for example, the articulated vehicle 10 may be equipped with an actuator for steering the rear wheels 24, and the permissible turning control amount may be the rear wheel steering angle δr of the tractor 20. Alternatively, for example, the trailer 30 may be equipped with a brake actuator, and the permissible turning control amount may be the trailer brake moment Mzt.

[0109] "Regarding the calculation process for allowable yaw angle" The input variables for the allowable yaw angle calculation process are not limited to three variables: lateral distance dy, tractor lateral speed vy, and tractor yaw rate γ, or four variables: these three plus longitudinal distance L. For example, the input variables for the allowable yaw angle calculation process may include any three of these four variables. Also, for example, the input variables for the allowable yaw angle calculation process may include only two of these four variables.

[0110] "Regarding the calculation process for permissible limits" The tolerance calculation process does not necessarily have to include a process for calculating the allowable yaw rate γp based on the allowable yaw angle φp as an input variable. For example, the tolerance calculation process may include a process for calculating the allowable yaw rate γp based on the lateral distance dy, tractor lateral speed vy, and tractor yaw rate γ as input variables. In that case, the tolerance calculation process does not include a process for calculating the allowable yaw angle.

[0111] The tolerance calculation process is not limited to a method in which the tolerance calculation process uses the values ​​of the model variables, which are updated each time, to calculate the allowable turning control amount. For example, the tolerance calculation process may include a process to predict the behavior of the vehicle when the front wheel steering angle δf is set in various ways, while using the values ​​of the model variables, which are updated each time in the above equations (c1) to (c7). In that case, the tolerance calculation process may include a process to set the front wheel steering angle threshold δf to the limit of the front wheel steering angle δf that is not predicted to occur when the vehicle comes into contact with an obstacle 140 or crosses the white line 142.

[0112] "Regarding the Model Variable Estimation Process" It is not mandatory that the model variable estimation process calculates the values ​​of model variables based on the closed-loop manipulated variable Mfb as an input variable. The input variables for the model variable estimation process may be, for example, the detected values ​​of sensors that detect the amount of extension and contraction of the trailer 30's suspension, such as potentiometers or differential transformers. In that case, the model variables may be the trailer weight mt including the cargo of the trailer 30. Alternatively, for example, the input variables for the model variable estimation process may be the detected values ​​of sensors that detect the force applied to the suspension, such as strain gauges, pressure sensors, or load cells.

[0113] The values ​​of the model variables to be calculated by the model variable estimation process are not limited to the values ​​of the variables exemplified in the above embodiment and its modified examples. "Regarding the process of acquiring environmental data" It is not mandatory for the environmental data acquisition process to acquire both image data Dp and distance point data Dd. For example, the environmental data acquisition process may acquire only one of the two, image data Dp or distance point data Dd. Furthermore, the environmental data acquired by the environmental data acquisition process may include location data from the Global Positioning System (GPS) and map data of the vicinity of the connected vehicle 10.

[0114] "Regarding the calculation process for open-loop manipulated variables" The open-loop manipulated variable calculation process does not necessarily have to be a process that calculates the open-loop manipulated variable Mff by algebraically solving the system of equations (c1) to (c7) above. The open-loop manipulated variable calculation process may include setting one of the values ​​detected by the sensor, such as the trailer yaw rate γt, as the target of estimation and substituting various values ​​for the variable that was previously unknown when solving algebraically. In that case, the open-loop manipulated variable calculation process includes a process of searching for the value of the unknown such that the value of the variable set as the target of estimation is closest to the sensor value.

[0115] It is not mandatory that the open-loop manipulated variable calculation process calculates the open-loop manipulated variable using calculations based on the values ​​of the model variables that are the target of the model variable estimation process. For example, the open-loop manipulated variable calculation process may be a process in which the PU performs a mapping calculation on the open-loop manipulated variable while the map data is stored in the memory. Here, the map data is data in which the output variable is the open-loop manipulated variable.

[0116] "Regarding the control quantities for closed-loop and open-loop manipulation quantity calculation processes." In the above embodiment, the control variable for the closed-loop operation amount calculation process and the control variable for the open-loop operation amount calculation process were the tractor yaw rate γ, but are not limited to this. The control variable may be, for example, the hitch angle θ.

[0117] "Regarding the operation process" The actuators that are operated based on the manipulated amount of the open-loop control are not limited to the actuators that steer the front wheels of the tractor 20. The actuators that are operated may, for example, be the actuators that steer the rear wheels of the tractor 20. The actuators that are operated may, for example, be the brake actuator 96. The actuators that are operated may, for example, be the brake actuator of the trailer 30 if the trailer 30 is equipped with a brake actuator. The actuators that are operated based on the manipulated amount of the open-loop control are not limited to any one of the actuators that steer the front wheels of the tractor 20, the actuators that steer the rear wheels of the tractor 20, the brake actuator 96, and the brake actuator of the trailer 30. For example, it may be both the actuators that steer the front wheels of the tractor 20 and the actuators that steer the rear wheels of the tractor 20. The actuators that are operated based on the manipulated amount of the open-loop control are not limited to any one of the four: the actuators that steer the front wheels of the tractor 20, the actuators that steer the rear wheels of the tractor 20, the brake actuator 96, and the brake actuator of the trailer 30. For example, if the thrust generating device of the tractor 20 is equipped with an in-wheel motor, the actuator that is operated based on the open-loop control amount may be the thrust generating device itself.

[0118] "Regarding methods for obtaining the values ​​of model variables" Figure 5 shows an example in which the trailer center of gravity hitch distance lft and the trailer center of gravity rear wheel distance lrt are obtained by input operations by the user of the coupled vehicle, but is not limited to this. For example, they may be estimated when the coupled vehicle 10 is stationary. This estimation may be achieved, for example, by using an equation for the balance of moments of the coupled vehicle 10 using the center of gravity of the tractor 20, the mass of the tractor 20, and the mass of the trailer 30.

[0119] "Regarding control devices for coupled vehicles" • In the above embodiment, an example is shown in which the steering control device 70 performs the processes shown in Figures 6 and 7, but it is not limited to this. For example, ADASECU 100 may perform the processes shown in Figures 6 and 7.

[0120] The control device for the coupled vehicle is not limited to one that includes a PU and a memory device and executes software processing. For example, it may include a dedicated hardware circuit, such as an ASIC, that executes at least a part of the various processes executed in the above embodiment. That is, the control device may include any of the following processing circuits (a) to (c): (a) A processing circuit comprising a processing device that executes all of the above processes according to a program and a program storage device such as a memory 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 processes according to a program and a dedicated hardware circuit that executes the remaining processes. (c) A processing circuit comprising a dedicated hardware circuit that executes all of the above processes. Here, there may be multiple software execution devices comprising a processing device and a program storage device, or multiple dedicated hardware circuits.

[0121] "Regarding the implementing body for the control method of coupled vehicles" It is not necessary that all entities performing each process in the above embodiments and their modified examples be processing circuits mounted on the connected vehicle 10.

[0122] Regarding coupled vehicles The coupled vehicle is not limited to a vehicle in which the trailer 30 is coupled to the rear of the tractor 20 via a ball joint 40. The coupled vehicle may also be a vehicle equipped with a so-called fifth-wheel coupling that connects the trailer 30 and the tractor 20 via a coupler. [Explanation of Symbols]

[0123] 10... Connected vehicles 20... Tractor 22…Front wheel 24... Rear wheel 30... Trailer 32...Wheel 40... Ball joint 42...axis 50... Steering system 52… Steering wheel 54… Reaction motor 56…Inverter 60…Front wheel steering motor 62... Inverter 70... Steering control device 90...braking system 91... Brake control device 100...ADASECU 140… Obstacle 142... White line

Claims

1. This applies to articulated vehicles comprising a tractor and a trailer towed by the tractor. It is configured to perform model variable estimation, environmental data acquisition, tolerance calculation, and countermeasure processing. The aforementioned model variable estimation process is a process for estimating the values ​​of model variables. The aforementioned model variables are variables that define the model of the trailer, The aforementioned environmental data acquisition process is a process for acquiring environmental data, which is data indicating environmental information in front of the direction of travel of the connected vehicle. The aforementioned tolerance calculation process is a process that calculates the allowable turning control amount based on the values ​​of the model variables as input variables and the environmental data. The allowable turning control amount is a variable that indicates the amount of turning that is permissible during the travel of the coupled vehicle. The aforementioned countermeasure is a control device for a coupled vehicle, which operates predetermined hardware to address a situation when the actual steering deviates from the allowable turning control amount.

2. The aforementioned allowable amount calculation process includes an allowable yaw angle calculation process, a current yaw angle acquisition process, an allowable yaw rate calculation process, and an allowable turning control amount conversion process. The aforementioned allowable yaw angle calculation process is a process that calculates the allowable yaw angle based on the lateral distance to the object in front and the lateral speed of the connected vehicle, which are input variables. The aforementioned current yaw angle acquisition process is a process for acquiring the yaw angle of the connected vehicle. The aforementioned allowable yaw rate calculation process is a process that calculates the allowable yaw rate based on the allowable yaw angle and the yaw angle of the connected vehicle as input variables. The control device for a connected vehicle according to claim 1, wherein the allowable turning control amount conversion process is a process that converts the allowable yaw rate as an input variable into the allowable turning control amount.

3. The control device for a coupled vehicle according to claim 2, wherein the allowable yaw rate is set to a constant yaw rate at which the yaw angle of the coupled vehicle reaches the allowable yaw angle within a predetermined time.

4. The control device for a coupled vehicle according to claim 2, wherein the input variable for the allowable yaw angle calculation process includes the yaw rate of the coupled vehicle.

5. The control device for a coupled vehicle according to claim 2, wherein the input variable for the allowable yaw angle calculation process includes the longitudinal distance between the coupled vehicle and the object.

6. The control device for a coupled vehicle according to claim 2, wherein the object is at least one of two things: an obstacle in front and a white line.

7. The aforementioned capacity calculation process includes a process that is performed when the connected vehicle is being driven by a driver, The aforementioned specified hardware includes a notification device, The control device for a coupled vehicle according to claim 1, wherein the countermeasure process includes a process of notifying the driver that the steering is outside the allowable turning control amount by operating the notification device.

8. The notification device includes a device for adjusting the reaction force applied to the operating section. The aforementioned operating unit is a component in which the driver inputs their intention to steer, The control device for a coupled vehicle according to claim 7, wherein the countermeasure processing includes a process of increasing the reaction force to the operation of the operating unit toward the side that increases the degree of deviation from the allowable turning control amount.

9. The control device for a coupled vehicle according to claim 1, wherein the countermeasure process includes a process for forcibly decelerating the coupled vehicle.

10. The control device for a coupled vehicle according to claim 1, wherein the countermeasure processing includes an automatic steering process that steers the coupled vehicle so that the actual turning amount of the coupled vehicle does not deviate from the allowable turning control amount, based on the value of the model variable as an input variable and the environmental data.

11. It is configured to perform open-loop manipulated variable calculation processing, closed-loop manipulated variable calculation processing, and operation processing. The open-loop operation amount calculation process is a process that calculates the open-loop operation amount, which is the operation amount for open-loop control, where a predetermined state quantity of the connected vehicle is the control quantity, based on calculations using input variables and model variables. The closed-loop operation amount calculation process is a process for calculating a closed-loop operation amount, which is an operation amount for closed-loop control where the predetermined state quantity is a controlled quantity. The aforementioned operation process is a process of operating the actuator of the tractor according to both the open-loop operation amount and the closed-loop operation amount. The control device for a coupled vehicle according to claim 1, wherein the model variable estimation process includes a process of estimating the value of the model variable based on the closed-loop operation amount as an input variable.

12. The aforementioned model variable is a variable whose value changes depending on at least one of two factors: the arrangement of the trailer's cargo and the mass of the cargo. The control device for a connected vehicle according to claim 1, wherein the model variable estimation process includes a process of updating the value of the model variable based on the detected value of a physical quantity that changes due to at least one of the input variables.

13. The model variables include at least one of the following three: the center of gravity variable of the trailer, the cornering coefficient of the trailer, and the vertical moment of inertia of the trailer. The control device for a connected vehicle according to claim 11, wherein the center of gravity variable of the trailer is a variable indicating the center of gravity of the trailer.

14. This applies to articulated vehicles comprising a tractor and a trailer towed by the tractor. This includes the execution of model variable estimation processing, environmental data acquisition processing, tolerance calculation processing, and countermeasure processing. The aforementioned model variable estimation process is a process for estimating the values ​​of model variables. The aforementioned model variables are variables that define the model of the trailer, The aforementioned environmental data acquisition process is a process for acquiring environmental data, which is data indicating environmental information in front of the direction of travel of the connected vehicle. The aforementioned tolerance calculation process is a process that calculates the allowable turning control amount based on the values ​​of the model variables as input variables and the environmental data. The allowable turning control amount is a variable that indicates the amount of turning that is permissible during the travel of the coupled vehicle. The aforementioned countermeasure is a control method for coupled vehicles, which involves operating predetermined hardware to address a situation when the actual steering deviates from the allowable turning control amount.

15. This applies to articulated vehicles comprising a tractor and a trailer towed by the tractor. This includes instructions for a computer to perform model variable estimation, environmental data acquisition, tolerance calculation, and countermeasure processing. The aforementioned model variable estimation process is a process for estimating the values ​​of model variables. The aforementioned model variables are variables that define the model of the trailer, The aforementioned environmental data acquisition process is a process for acquiring environmental data, which is data indicating environmental information in front of the direction of travel of the connected vehicle. The aforementioned tolerance calculation process is a process that calculates the allowable turning control amount based on the values ​​of the model variables as input variables and the environmental data. The allowable turning control amount is a variable that indicates the amount of turning that is permissible during the travel of the coupled vehicle. The aforementioned countermeasure is a control program for a coupled vehicle, which operates predetermined hardware to address a situation when the actual steering deviates from the allowable turning control amount.

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