Mobile control system

Abstract

To more appropriately calculate an actuator command value when switching a low-order application in conjunction with switching of a high-order application.SOLUTION: A moving body control system includes: a high-order ECU that calculates a required physical quantity according to each of switchable first and second high-order applications; a low-order ECU that receives the required physical quantity and calculates an actuator command value for causing a detected physical quantity to follow the required physical quantity according to the first or second low-order application while performing switching between the first low-order application and the second low-order application in conjunction with switching of the high-order applications; and an actuator. The first low-order application and the second low-order application implement control in which the followability of the detected physical quantity to the required physical quantity is different from each other. The low-order ECU executes amount-of-charge restriction processing that moderates a change from a previous value to a current value of the required physical quantity, and substitutes the detected physical quantity for the previous value of the amount-of-charge restriction processing in accordance with the switching between the first high-order application and the second high-order application.SELECTED DRAWING: Figure 4

Description

[[Technical Field]]

[0001] The present disclosure relates to a moving body control system. [[Background Art]]

[0002] Patent Document 1 discloses a vehicle steering control apparatus. The steering control apparatus is configured to be switchable between an assist control that generates an assist torque corresponding to a driver's steering torque and a follow-up control that causes a detected value of a physical quantity related to steering to follow a target value of the physical quantity. [[Prior Art Literature]] [[Patent Literature]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2020-069990 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] A moving body control system comprising: a higher-level ECU that calculates a requested physical quantity of a moving body (for example, a requested steering angle of a vehicle) in accordance with a plurality of switchable higher-level applications; and a lower-level ECU that receives the requested physical quantity from the higher-level electronic control unit and calculates an actuator command value for causing a detected physical quantity (for example, a detected steering angle) to follow the requested physical quantity while switching a plurality of lower-level applications in conjunction with switching of the plurality of higher-level applications, has the following problem. That is, if a timing deviation occurs between the switching of the higher-level application and the switching of the lower-level application, the lower-level electronic control unit may become unable to appropriately calculate the actuator command value.

[0005] The present disclosure has been made in view of the problems described above, and an object of the present disclosure is to enable more appropriate calculation of an actuator command value when switching a lower-level application in conjunction with switching of a higher-level application. [Means for solving the problem]

[0006] A mobile vehicle control system according to a first aspect of the present disclosure comprises a higher-level electronic control unit, a lower-level electronic control unit, and an actuator. The higher-level electronic control unit calculates a required physical quantity, which is a required value of a physical quantity related to the operation of the mobile vehicle, according to a switchable first and second higher-level application. The lower-level electronic control unit receives the required physical quantity from the higher-level electronic control unit and, in conjunction with the switching between the first and second higher-level applications, switches between the first and second lower-level applications, while calculating an actuator command value to cause a detected physical quantity, which is a detected value of a physical quantity, to track the required physical quantity according to the first or second lower-level application. The actuator is controlled according to the actuator command value. The first and second lower-level applications realize control in which the tracking of the detected physical quantity with respect to the required physical quantity is different from that of the first and second lower-level applications. The lower-level electronic control unit performs a change amount suppression process that slows down the change from the previous value to the current value compared to the case where the requested physical quantity is changed stepwise from the previous value to the current value, and substitutes the detected physical quantity into the previous value of the change amount suppression process in response to the switching between the first higher-level application and the second higher-level application.

[0007] Each of the mobile control systems according to the second and third embodiments of this disclosure differs from the mobile control system according to the first embodiment in the following respects: In the second embodiment, the lower-level electronic control unit substitutes an estimated physical quantity, which is an estimated value of a physical quantity based on one or more parameters indicating the behavior of the mobile body, into the previous value of the change amount suppression process in response to switching between the first higher-level application and the second higher-level application. In the third embodiment, the lower-level electronic control unit substitutes zero into the previous value of the change amount suppression process in response to switching between the first higher-level application and the second higher-level application. [Effects of the Invention]

[0008] According to each of the first to third aspects of this disclosure, when switching a lower-level application in conjunction with switching a higher-level application, the actuator command value can be calculated more appropriately. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of the configuration of a vehicle steering system according to an embodiment. [Figure 2] This is a block diagram showing the functional configuration of steering control according to an embodiment. [Figure 3] This diagram illustrates the challenges that arise when the relationship between higher-level and lower-level apps becomes inconsistent. [Figure 4] This flowchart shows the processing related to the first control example according to the embodiment. [Figure 5] This diagram illustrates the operation of a comparative example (A) and the first control example (B) of steering control. [Figure 6] This flowchart shows the processing related to the second control example according to the embodiment. [Figure 7] This flowchart shows the processing related to the third control example according to the embodiment. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described with reference to the attached drawings.

[0011] 1. Vehicle steering system configuration Figure 1 shows an example of the configuration of a vehicle steering system 100 according to an embodiment. The vehicle steering system 100 is applied to a vehicle 1 (for example, a four-wheeled vehicle). The vehicle steering system 100 comprises a steering device 10, sensors 20, a higher-level electronic control unit (higher-level ECU) 30, and a lower-level electronic control unit (lower-level ECU) 40. The vehicle 1 may be an autonomous vehicle. The vehicle steering system 100 corresponds to an example of a "mobile vehicle control system" according to this disclosure.

[0012] The steering system 10 is a device for steering the wheels 2 of the vehicle 1. The steering system 10 includes a steering wheel 11, a steering shaft 12, and a steering unit 13. The steering wheel 11 is operated by the driver of the vehicle 1. The steering unit 13 steers the wheels 2. The steering unit 13 comprises a steering actuator 14, a steering shaft (rack shaft) 15, and a tie rod 16. The steering actuator 14 is, for example, an electric motor and generates torque to steer the wheels 2. The wheels (steered wheels) 2 are connected to the steering shaft 15 via the tie rod 16. The steering actuator 14 causes the steering shaft 15 to move linearly in its axial direction, thereby changing the steering angle θ of the wheels 2 via the tie rod 16. The steering angle θ corresponds to an example of a "physical quantity related to the driving operation (steering) of a moving body" as described herein. The steering actuator 14 is used as an electric power steering (EPS) device that assists the driver in steering. The steering system 10 may also be a steer-by-wire system in which the steering wheel 11 is mechanically separated from the wheels (steered wheels) 2.

[0013] The sensors 20 include, for example, a recognition sensor, a steering angle sensor, a yaw rate sensor, a vehicle speed sensor, and a longitudinal acceleration sensor. The recognition sensor recognizes (detects) the surrounding conditions of the vehicle 1. The recognition sensor includes, for example, a camera C. Alternatively, the recognition sensor may include, in place of or together with, a camera C, at least one of, for example, a millimeter-wave radar and a LiDAR (Laser Imaging Detection and Ranging). The steering angle sensor is attached to the steering actuator 14 and detects the steering angle θ (detected steering angle θd) of the wheel 2. The yaw rate sensor, vehicle speed sensor, and longitudinal acceleration sensor detect the yaw rate, vehicle speed, and longitudinal acceleration of the vehicle 1, respectively.

[0014] The upper ECU 30 and the lower ECU 40 can communicate with each other. For example, the upper ECU 30 and the lower ECU 40 are mounted on vehicle 1, and the upper ECU 30 is connected to the lower ECU 40 via communication line 3. However, the upper ECU 30 does not necessarily have to be mounted on vehicle 1. That is, the upper ECU 30 may be located outside vehicle 1 and configured to communicate with the lower ECU 40 via a wireless communication network.

[0015] As will be described in detail later, the higher-level ECU 30 works in cooperation with the lower-level ECU 40 to perform steering control of the vehicle 1. The higher-level ECU 30 includes a processing circuit 31 and a memory 32. The processing circuit 31 performs various processes, including calculating the required steering angle θr based on information from the camera C. The required steering angle θr is the required value for the steering angle θ of the wheel 2. The memory 32 stores various information necessary for the processing by the processing circuit 31. The processing circuit 31 executes a computer program, thereby realizing the various processes performed by the higher-level ECU 30. The computer program is stored in the memory 32. Alternatively, the computer program may be recorded on a computer-readable recording medium.

[0016] The lower-level ECU 40 includes a processing circuit 41 and a memory 42. The processing circuit 41 performs various processes, including calculating a torque command value Tc according to the difference (steering angle difference Δθ) between the requested steering angle θr received from the upper-level ECU 30 and the detected steering angle θd (in other words, the actual steering angle). The torque command value Tc is an actuator command value commanded to the steering actuator 14 to make the detected steering angle θd follow the requested steering angle θr. The memory 42 stores various information necessary for the processing by the processing circuit 41. The various processes performed by the lower-level ECU 40 are realized by the processing circuit 41 executing a computer program. The computer program is stored in the memory 42. Alternatively, the computer program may be recorded on a computer-readable recording medium.

[0017] 2. Steering control Fig. 2 is a block diagram showing the functional configuration of steering control according to an embodiment. As described above, steering control is executed through cooperation between the upper ECU 30 and the lower ECU 40. As shown in Fig. 2, the upper ECU 30 includes a requested steering angle calculation unit 33 and an application switching unit 34.

[0018] To calculate the requested steering angle θr, the requested steering angle calculation unit 33 uses a plurality of upper-level applications (hereinafter abbreviated as "upper apps"). The plurality of upper-level applications are included in the computer program stored in the memory 32. More specifically, the upper-level applications are steering assistance applications that assist steering by a driver. In the example shown in Fig. 2, two upper applications A and B correspond to an example of the plurality of upper-level applications described herein. Note that the number of the plurality of upper-level applications may be three or more.

[0019] Specifically, the upper application A is an application that provides a function of calculating the requested steering angle θra so as to avoid an obstacle, for example, when an obstacle present on the traveling lane ahead of the vehicle 1 is detected by the camera C. The upper application B is an application that provides a function of calculating the requested steering angle θrb so that the vehicle 1 travels while following the traveling lane based on vehicle surrounding information from the camera C, for example. The requested steering angle calculation unit 33 calculates the requested steering angles θra and θrb of each of the upper applications A and B in parallel at a predetermined control cycle (calculation cycle).

[0020] (Application switching unit 34) The application switching unit 34 switches between higher-level applications A and B by selectively choosing between higher-level applications A and B. This switching is performed, for example, as follows: The application switching unit 34 basically selects higher-level application B to make vehicle 1 follow the driving lane. Then, when camera C detects an obstacle on the driving lane, the application switching unit 34 selects higher-level application A, that is, switches from higher-level application B to higher-level application A. When it is determined from the surrounding information from camera C that vehicle 1 has finished avoiding the obstacle, the application switching unit 34 selects higher-level application B, that is, switches from higher-level application A to higher-level application B. With this switching, the requested steering angle θr output from the application switching unit 34 is switched stepwise between the requested steering angle θra and the requested steering angle θrb.

[0021] The higher-level ECU 30 transmits the calculated requested steering angle θr (more specifically, the requested steering angle θra or θrb calculated by the higher-level application A or B selected by the application switching unit 34) to the lower-level ECU 40 via the communication line 3. Along with the requested steering angle θr, the higher-level ECU 30 also transmits "application switching information" to the lower-level ECU 40. The application switching information is, for example, ID (Identification) information that identifies the higher-level application A or B currently selected by the application switching unit 34.

[0022] On the other hand, the lower-level ECU 40 includes a change amount suppression unit 43, a subtraction unit 44, an application switching unit 45, and a torque calculation unit 46, as shown in Figure 2. To calculate the torque command value Tc, the torque calculation unit 46 utilizes multiple lower-level applications (hereinafter abbreviated as "lower-level applications"). These multiple lower-level applications are included in the computer program stored in the memory 42. More specifically, the lower-level applications are also steering support applications that assist the driver in steering. Each lower-level application is paired with one of the multiple higher-level applications. In the example shown in Figure 2, higher-level application A is paired with lower-level application A, and higher-level application B is paired with lower-level application B.

[0023] To suppress abrupt changes in the requested steering angle θr, the change amount suppression unit 43 performs change amount suppression processing (in other words, smoothing processing). The change amount suppression processing makes the change from the previous value θr(n-1) to the current value θr(n) more gradual compared to the case where the requested steering angle θr is changed stepwise from the previous value θr(n-1) to the current value θr(n). More specifically, the change amount suppression processing is, for example, a process that limits the change amount Δθr from the previous value θr(n-1) to the current value θr(n) to a predetermined upper limit or less. The change amount suppression unit 43 outputs the requested steering angle θrs after the change amount suppression processing to the subtraction unit 44. In addition, the change amount suppression processing may also include filtering processing that applies a low-pass filter (LPF) to the time-series data of the requested steering angle θr. Furthermore, the change amount suppression processing of the requested steering angle θr may also be performed similarly on the side of the higher-level ECU 30.

[0024] The subtraction unit 44 calculates the steering angle difference Δθ by subtracting the detected steering angle (current actual steering angle) θd from the requested steering angle θrs output from the change amount suppression unit 43, and transmits the calculated steering angle difference Δθ to the application switching unit 45. Note that the estimated steering angle θe, described later, may be used instead of the detected steering angle θd for calculating the steering angle difference Δθ.

[0025] Application switching information transmitted from the higher-level ECU 30 to the lower-level ECU 40 is input to the application switching unit 45. Based on the application switching information (i.e., application switching request), the application switching unit 45 switches the lower-level application in conjunction with the application switching of the higher-level application by the application switching unit 34. Specifically, the application switching unit 45 switches the lower-level application used in the torque calculation unit 46 between lower-level application A and lower-level application B by selectively selecting lower-level applications A and B in conjunction with the switching of the higher-level application. More specifically, the output destination of the steering angle difference Δθ received from the subtraction unit 44 is switched stepwise between lower-level application A and lower-level application B.

[0026] Sub-app A is an application that provides the function to calculate a torque command value Tc corresponding to the steering angle difference Δθ based on the requested steering angle θra of the higher-level application A. Similarly, sub-app B is an application that provides the function to calculate a torque command value Tc corresponding to the steering angle difference Δθ based on the requested steering angle θrb of the higher-level application B.

[0027] As shown in Figure 2, the relationship between the steering angle difference Δθ and the torque command value Tc (referred to as "torque gain") differs between lower-level applications A and B. Specifically, both lower-level applications A and B share the characteristic that the larger the steering angle difference Δθ (absolute value), the larger the torque command value Tc (absolute value). Furthermore, the magnitude of the torque command value Tc for the same steering angle difference Δθ is determined to be greater in lower-level application A than in lower-level application B. In other words, the torque gain is determined to be greater in lower-level application A than in lower-level application B.

[0028] Therefore, when lower-level application A is selected, control with high responsiveness of the detected steering angle (actual steering angle) θd to the requested steering angle (target steering angle) θr is achieved. As a result, as shown in Figure 3 below, the steering angle difference Δθ while lower-level application A is selected becomes smaller. This allows the detected steering angle (actual steering angle) θd to quickly approach the requested steering angle θra, for example, when higher-level application A calculates the requested steering angle θra to avoid an obstacle. On the other hand, when lower-level application B is selected, control with lower responsiveness of the detected steering angle θd to the requested steering angle θr is achieved compared to when lower-level application A is selected. As a result, as shown in Figure 3, the steering angle difference Δθ while lower-level application B is selected becomes larger.

[0029] The relationship between the steering angle difference Δθ and the torque command value Tc, as shown in Figure 2, is stored as a map in memory 42 for each lower-level application. When lower-level application A is selected by the application switching unit 45, the torque calculation unit 46 calculates the torque command value Tc corresponding to the steering angle difference Δθ from the map corresponding to lower-level application A. Similarly, when lower-level application B is selected, the torque calculation unit 46 calculates the torque command value Tc corresponding to the steering angle difference Δθ from the map corresponding to lower-level application B. The steering actuator 14 is controlled according to the torque command value Tc and generates torque corresponding to the torque command value Tc.

[0030] Next, the problems of the vehicle steering system 100 according to the embodiment will be explained. As described above, when a lower-level application is switched in conjunction with the switching of a higher-level application, if there is a timing difference between the switching of the higher-level application and the switching of the lower-level application, the lower-level ECU 40 may not be able to properly calculate the torque command value Tc.

[0031] Specifically, as described above, if there is a difference in responsiveness between the control implemented by lower-level application A and lower-level application B (in other words, if there is a difference in torque gain), the following problems arise. That is, if a lower-level application switches simultaneously with a higher-level application switch, the lower-level ECU 40 can appropriately calculate the torque command value Tc according to lower-level application A corresponding to the switched-out higher-level application A (or lower-level application B corresponding to the switched-out higher-level application B). On the other hand, due to the change amount suppression process described above, or communication delays between the higher-level ECU 30 and the lower-level ECU 40, there may be a mismatch between the higher-level application that calculates the required steering angle θr and the lower-level application that calculates the torque command value Tc when the higher-level application switches. When the relationship between the higher-level application and the lower-level application becomes mismatched in this way, as illustrated in Figure 3, the lower-level ECU 40 will no longer be able to appropriately calculate the torque command value Tc in response to the application switching request from the higher-level ECU 30. Additionally, if the change suppression process is in effect, when switching between top-level applications, the top-level application that calculated the current value θr(n) will temporarily be different from the top-level application that calculated the previous value θr(n-1).

[0032] Figure 3 is a diagram that illustrates the challenges that arise when the relationship between the higher-level application and the lower-level application becomes inconsistent. Figure 3 shows an example where a switch from higher-level application A to higher-level application B occurs around time t1, and then a switch from higher-level application B to higher-level application A occurs around time t2. From Figure 3, it can be seen that during the selection of lower-level application A, which has a large torque gain (before time t1 and after time t2), the detected steering angle θd follows the required steering angle θr (θra) well. In this example, a large steering angle difference Δθ occurs between the required steering angle θrb of higher-level application B and the detected steering angle θd around each time point t1 and t2 when the higher-level application switches.

[0033] First, we will explain the switching from higher-level application A to higher-level application B around time t1. If the relationship between the higher-level and lower-level applications is not inconsistent and the lower-level application is switched simultaneously with the higher-level application, the torque command value Tc is calculated appropriately, as shown in the waveform labeled "simultaneous switching". On the other hand, if an inconsistency occurs where the switching from lower-level application A to lower-level application B occurs before the switching from higher-level application A to higher-level application B, the lower-level ECU 40 will calculate the torque command value Tc to reduce the steering angle difference Δθ corresponding to the required steering angle θra based on higher-level application A, according to lower-level application B which has a smaller torque gain. As a result, the torque command value Tc decreases compared to the case of simultaneous switching where lower-level application A is used. Also, if an inconsistency occurs where the switching from higher-level application A to higher-level application B occurs before the switching from lower-level application A to lower-level application B, the lower-level ECU 40 will calculate the torque command value Tc to reduce the large steering angle difference Δθ (see Figure 3) corresponding to the required steering angle θrb based on higher-level application B, according to lower-level application A which has a larger torque gain. As a result, the torque command value Tc increases compared to the case of simultaneous switching, as shown in the waveform labeled "Increased Torque (Torque Switching Delay)" in Figure 3. This can lead to unnecessary torque being applied to the driver via the steering wheel 11.

[0034] Next, we will explain the switching from higher-level application B to higher-level application A around time t2. In this example as well, in the case of "simultaneous switching," the torque command value Tc is calculated appropriately. On the other hand, if a mismatch occurs where the switching from higher-level application B to higher-level application A occurs before the switching from lower-level application B to lower-level application A, the lower-level ECU 40 will calculate the torque command value Tc to reduce the steering angle difference Δθ corresponding to the required steering angle θra based on higher-level application A, according to lower-level application B which has a small torque gain. As a result, the torque command value Tc decreases compared to the case of simultaneous switching where lower-level application A is used. Also, if a mismatch occurs where the switching from lower-level application B to lower-level application A occurs before the switching from higher-level application B to higher-level application A, the lower-level ECU 40 will calculate the torque command value Tc to reduce the large steering angle difference Δθ (see Figure 3) corresponding to the required steering angle θrb based on higher-level application B, according to lower-level application A which has a large torque gain. As a result, the torque command value Tc increases compared to the case of simultaneous switching, as shown in the waveform labeled "torque increase (torque switching advance)" in Figure 3. This could also lead to unnecessary torque being applied to the driver via the steering wheel 11.

[0035] 2-1. First Control Example In view of the above-mentioned problems, in the first control example according to this embodiment, the lower-level ECU 40 uses the detected steering angle θd as the previous value for the change amount suppression process, instead of the previous value of the requested steering angle θr θr(n-1). More specifically, for example, the current value of the detected steering angle θd θd θd(n) is used.

[0036] Figure 4 is a flowchart showing the processing for a first control example according to the embodiment. The processing in this flowchart is executed by the lower ECU 40 at a predetermined control cycle.

[0037] In step S100, the lower ECU 40 obtains the requested steering angle θr (θra or θrb) and application switching information from the upper ECU 30, and also obtains the detected steering angle θd from the sensors 20 (steering angle sensor).

[0038] Next, in step S102, the lower ECU 40 determines whether or not a higher-level application has been switched based on the application switching information. For example, if the ID information of the higher-level application included in the application switching information obtained this time is different from the ID information obtained last time, the lower ECU 40 determines that a higher-level application has been switched. If a higher-level application has been switched, the process proceeds to step S104.

[0039] In step S104, the lower ECU 40 (change amount suppression unit 43) substitutes the current value θd(n) of the detected steering angle θd obtained in step S100 for the previous value θr(n-1) of the requested steering angle θr in the change amount suppression process described above. In other words, the previous value θr(n-1) is replaced by the current value θd(n).

[0040] After step S104, the process proceeds to step S106. Also, if there is no switching of the higher-level application (step S102; No), the process proceeds to step S106 without replacing the previous value θr(n-1) with the current value θd(n).

[0041] In step S106, the lower ECU 40 performs a change amount suppression process. As a result, the requested steering angle (current value) θrs(n) after change amount suppression is calculated. Next, in step S108, the lower ECU 40 updates the previous value θr(n-1) of the change amount suppression process with the current value θrs(n). The updated previous value θr(n-1) is used in the next control cycle.

[0042] In step S110, following step S108, the lower-level ECU 40 calculates the difference between the requested steering angle θrs(n) after suppressing the amount of change and the current value of the detected steering angle θd(n) as the steering angle difference Δθ. Next, in step S112, the lower-level ECU 40 calculates a torque command value Tc corresponding to the calculated steering angle difference Δθ using the same lower-level application as the currently selected higher-level application based on the current (latest) application switching information.

[0043] Figure 5 is a diagram illustrating the operation of a comparative example (A) and the first control example (B) of steering control.

[0044] The comparative example corresponds to a case where the previous value θr(n-1) is not replaced with the detected steering angle (current value) θd(n) when switching to a higher-level application. Specifically, as shown in Figure 5(A), in response to the switch from higher-level application B to higher-level application A around time t2, the requested steering angle θr switches in a stepwise manner from the previous value θr(0), which is the requested steering angle θrb based on higher-level application B, to the current value θr(1), which is the requested steering angle θra based on higher-level application A. In addition, in Figure 5(A), the detected steering angle θd is located between the requested steering angles θra and θrb of higher-level applications A and B before and after the switch.

[0045] In the change amount suppression process related to the comparative example, the required steering angle θrs(1) is calculated by suppressing the change in the required steering angle θr due to this step-like switching. In the next calculation cycle after this calculation cycle, the change amount suppression process is executed using the required steering angle θrs(1) as the previous value and the required steering angle (current value) θr(2) based on the higher-level application A as the current value. As a result, the required steering angle θrs(2) after change amount suppression is calculated. This is the same in subsequent calculation cycles. In the example shown in Figure 5(A), the required steering angle θrs after change amount suppression then converges to the required steering angle θra of the higher-level application A after the switching.

[0046] According to the change amount suppression process in the comparative example, the requested steering angle θrs (θrs(1) and θrs(2)) after change amount suppression immediately after switching applications is located further away from the detected steering angle θd than the requested steering angle θra after switching. As a result, the torque command value Tc calculated by the lower-level ECU 40 based on the steering angle difference Δθ between the requested steering angle θrs after change amount suppression and the detected steering angle (actual steering angle) θd changes in the opposite direction to the target of the higher-level application A after switching (the direction on the plane of the paper in Figure 5(A)). As a result, the detected steering angle (actual steering angle) θd changes in the opposite direction to the requested steering angle θra. Thus, according to the comparative example, unnecessary torque changes may occur when switching applications. More specifically, since the torque command value Tc after switching is calculated according to the lower-level application A which has a large torque gain, unnecessary torque changes may become large.

[0047] In contrast, according to the change amount suppression process in the first control example, as shown in Figure 5(B), the previous value θr(0) is replaced by the detected steering angle (current value) θd(1). As a result, the requested steering angle θrs (θrs(1), etc.) after change amount suppression immediately after switching applications is located closer to the detected steering angle θd than to the requested steering angle θra after switching. Consequently, the torque command value Tc calculated by the lower ECU 40 changes in the direction targeted by the higher application A after switching (downward direction in Figure 5(B)). Therefore, the detected steering angle (actual steering angle) θd can be changed to approach the requested steering angle θra. Thus, according to the first control example, unnecessary torque changes caused by switching applications can be suppressed. This leads to the suppression of applying unnecessary torque to the driver.

[0048] As described above, according to the first control example, when switching a lower-level application in conjunction with switching a higher-level application, the torque command value Tc (actuator command value) can be calculated more appropriately. More specifically, the torque command value Tc of the steering actuator 14 is determined based on the steering angle difference Δθ as described above, that is, it is determined based on the detected steering angle (actual steering angle) θd. For this reason, the detected steering angle θd is suitable as the previous value for the change amount suppression processing when switching a higher-level application in which the requested steering angle θr changes in steps.

[0049] 2-2. Second Control Example In the second control example, the lower-level ECU 40 uses the estimated steering angle θe as the previous value for the change amount suppression process, instead of the previous value of the requested steering angle θr, θr(n-1). More specifically, for example, the current value of the estimated steering angle θe, θe(n), is used. The estimated steering angle θe is calculated based on one or more parameters that indicate vehicle behavior. These one or more parameters are, for example, vehicle speed and yaw rate.

[0050] Figure 6 is a flowchart showing the processing of a second control example according to the embodiment. This flowchart differs from the flowchart shown in Figure 4 in that the processing of step S200 is executed instead of step S104.

[0051] In Figure 6, if there is a switch in the higher-level application, the process proceeds to step S200. In step S200, the lower-level ECU 40 (change amount suppression unit 43) calculates the estimated steering angle θe based on the vehicle speed and yaw rate acquired using the sensors 20. The calculation of the estimated steering angle θe may be performed by another ECU such as the higher-level ECU 30. Then, the lower-level ECU 40 substitutes the calculated estimated steering angle (current value) θe(n) into the previous value θr(n-1) of the requested steering angle θr in the change amount suppression process. In other words, the previous value θr(n-1) is replaced by the current value θe(n).

[0052] The second control example also allows for a more appropriate calculation of the torque command value Tc (actuator command value) when switching lower-level applications in conjunction with the switching of higher-level applications. More specifically, the estimated steering angle θe is basically close to the detected steering angle θd. For this reason, like the detected steering angle θd, the estimated steering angle θe is also suitable as the previous value for the change amount suppression processing when switching higher-level applications where the required steering angle θr changes in steps. Furthermore, in the steer-by-wire steering system described above, situations may arise where the vehicle behavior and the detected steering angle (actual steering angle) θd do not match. In such situations, the estimated steering angle θe is more suitable than the detected steering angle θd as the previous value for the change amount suppression processing when switching higher-level applications.

[0053] 2-3. Third Control Example In the third control example, the lower-level ECU 40 uses zero as the previous value for the requested steering angle θr, instead of the previous value θr(n-1), as the previous value for the change amount suppression process, in response to the switching of the higher-level application.

[0054] Figure 7 is a flowchart showing the processing for a third control example according to the embodiment. This flowchart differs from the flowchart shown in Figure 4 in that the processing in step S300 is executed instead of step S104.

[0055] In Figure 7, if there is a switch in the higher-level application, the process proceeds to step S300. In step 300, the lower-level ECU 40 (change amount suppression unit 43) substitutes zero for the previous value θr(n-1) of the requested steering angle θr in the change amount suppression process. In other words, the previous value θr(n-1) is replaced with zero.

[0056] The third control example also allows for a more appropriate calculation of the torque command value Tc (actuator command value) when switching a lower-level application in conjunction with switching a higher-level application. More specifically, using the zero point of the steering angle θ as the previous value for the change amount suppression process is preferable in preventing the steering angle difference Δθ calculated at the time of switching from becoming excessive when the signs of the required steering angles θr of the two higher-level applications before and after the switch are different, as shown in the example in Figure 5(A).

[0057] 3. Other examples of mobile control systems The “mobile entity” in this disclosure is not limited to vehicles such as automobiles, but may also be, for example, construction machinery, robots, aircraft, or ships. Furthermore, the “mobile entity control system” in this disclosure is not limited to the vehicle steering system 100 that performs the steering control described above, as long as it includes the “higher-level ECU,” “lower-level ECU,” and “actuator” in this disclosure.

[0058] Specifically, the vehicle control system may include, for example, an actuator capable of driving the accelerator pedal, as the “actuator” according to this disclosure. In this example of the actuator, “physical quantities related to driving operations (acceleration and deceleration)” include, for example, longitudinal acceleration or vehicle speed. The higher-level application may include, for example, a first higher-level application that calculates the required longitudinal acceleration or required vehicle speed for acceleration, and a second higher-level application that calculates the required longitudinal acceleration or required vehicle speed for deceleration.

[0059] Furthermore, the “actuator” in this disclosure may be, for example, an actuator capable of driving a brake pedal. In this example of an actuator, “physical quantities related to driving operations (braking)” may include, for example, longitudinal acceleration or vehicle speed. The higher-level application may include, for example, a first higher-level application that calculates the required longitudinal acceleration or required vehicle speed for braking based on first information, and a second higher-level application that calculates the required longitudinal acceleration or required vehicle speed for braking based on second information.

[0060] Furthermore, the “actuator” in this disclosure may be, for example, a powertrain (at least one of an internal combustion engine and an electric motor for vehicle propulsion). In this example of an actuator, the “required physical quantity related to driving operation (e.g., acceleration / deceleration)” may be, for example, longitudinal acceleration or vehicle speed. An example of a higher-level application is the same as the higher-level application in the example of an actuator capable of driving the accelerator pedal.

[0061] In addition, the mobile body control system in an example that uses two or more higher-level applications in which the "required physical quantity" is switched continuously, as in the case of switching the requested steering angle θr by the application switching unit 34 (see Figure 2), may be configured as follows: That is, in order to provide more versatile mobile body control, the mobile body control system may be configured to switch whether or not to use the "detected physical quantity" (the same applies to the "estimated physical quantity" and the case of zero) as the previous value of the requested physical quantity in the change amount suppression process, depending on the combination of higher-level applications to be switched. [Explanation of Symbols]

[0062] 1 Vehicle, 2 Wheels, 3 Communication lines, 10 Steering gear, 14 Steering actuators, 20 Sensors, 30 Higher-level ECU, 40 Lower-level ECU, 100 Vehicle steering system

Claims

1. A higher-level electronic control unit that calculates required physical quantities, which are required values ​​of physical quantities related to the operation of a moving object, according to a first and second higher-level application that can be switched between, A lower-level electronic control unit receives the requested physical quantity from the higher-level electronic control unit and, in conjunction with the switching between the first higher-level application and the second higher-level application, switches between the first lower-level application and the second lower-level application, and calculates an actuator command value to cause the detected physical quantity, which is the detected value of the physical quantity, to track the requested physical quantity according to the first or second lower-level application. An actuator controlled according to the actuator command value, Equipped with, The first subordinate application and the second subordinate application implement control in which the tracking of the detected physical quantity to the requested physical quantity is different from that of the first subordinate application. The aforementioned lower-level electronic control unit is Compared to the case where the requested physical quantity is changed stepwise from the previous value to the current value, a change amount suppression process is performed to make the change from the previous value to the current value more gradual. In response to the switching between the first higher-level application and the second higher-level application, the detected physical quantity is substituted into the previous value of the change amount suppression process. Mobile control system.

2. A higher-level electronic control unit that calculates required physical quantities, which are required values ​​of physical quantities related to the operation of a moving object, according to a first and second higher-level application that can be switched between, A lower-level electronic control unit receives the requested physical quantity from the higher-level electronic control unit and, in conjunction with the switching between the first higher-level application and the second higher-level application, switches between the first lower-level application and the second lower-level application, and calculates an actuator command value to cause the detected physical quantity, which is the detected value of the physical quantity, to track the requested physical quantity according to the first or second lower-level application. An actuator controlled according to the actuator command value, Equipped with, The first subordinate application and the second subordinate application implement control in which the tracking of the detected physical quantity to the requested physical quantity is different from that of the first subordinate application. The aforementioned lower-level electronic control unit is Compared to the case where the requested physical quantity is changed stepwise from the previous value to the current value, a change amount suppression process is performed to make the change from the previous value to the current value more gradual. In response to the switching between the first higher-level application and the second higher-level application, the estimated physical quantity, which is an estimated value of the physical quantity based on one or more parameters indicating the behavior of the moving body, is substituted into the previous value of the change amount suppression process. Mobile control system.

3. A mobile body control system according to claim 1 or 2, The aforementioned moving object is a vehicle, The aforementioned physical quantity is the steering angle of the vehicle's wheels. The actuator is an electric motor that generates torque to change the steering angle, The actuator command value is a torque command value that causes the detected steering angle, as the detected physical quantity, to follow the required steering angle, as the required physical quantity. Mobile control system.

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