Automatic brake control device for vehicles

Abstract

To enable delicate brake control through improving quick response in brake control under the control of a driving support system such as ADAS.SOLUTION: A vehicle automatic brake control device that is an automatic brake control device controlling a brake device under the control of a driving support system comprises: a first electronic control device which controls the driving support system; and a plurality of electronic control units which are communication-connected capable of exchanging information with each other. Instructions transmitted from the first electronic control device to the other electronic control units to control the brake device includes: a first instruction to control behavior of a vehicle; and a second instruction which has instruction contents different from the first instruction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an automatic brake control device for a vehicle. [Background technology]

[0002] Driver assistance systems, also known as ADAS (Advanced Driver-Assistance Systems), are control systems that assist the driver by automatically controlling the vehicle on behalf of the driver, and vehicles are equipped with systems that perform a variety of functions, such as ACC (Adaptive Cruise Control System), FCW (Forward Collision Warning), AEBS (Advanced Emergency Braking System), NV / PD (Night Vision / Pedestrian Detection), TRS (Traffic Sign Recognition), LKAS (Lane Keeping Assist System), BSM (Blind Spot Monitoring), and APA (Advanced Parking Assist).

[0003] The most commonly used control in ADAS is brake control. In ADAS, the brake control is performed by a brake control device configured with an ECU (Electronic Control Unit) based on information from various on-board sensors and external sensors such as cameras (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-182753 A Summary of the Invention [Problem to be solved by the invention]

[0005] In brake control under ADAS control, the purpose of control is to reduce the vehicle speed, and the detection signals from each wheel speed sensor are input to the ECU. Based on deceleration instructions from the ADAS, the brake device is controlled (hydraulic pressure control) to reduce the vehicle speed according to the situation.

[0006] However, if brake control in ADAS control is performed only based on deceleration commands, there is a problem that precise control cannot be performed that takes into account the amount of operation and hydraulic pressure fluctuations in the brake device that do not affect the vehicle speed.

[0007] Specifically, the gap between the pad and rotor in the brake caliper is essential to prevent brake friction from occurring when the vehicle is traveling, but when the vehicle is stopped in an emergency, the action of closing the gap causes a delay in the generation of brake friction, which reduces the responsiveness of the brakes. On the other hand, if it were possible to close the gap of the brake caliper in advance in various situations in the control of the ADAS, the problem of reduced responsiveness described above would be solved, but a conventional brake control device that controls the brake device using the detection signal of a wheel speed sensor based on a deceleration command from the ADAS cannot perform precise control such as closing the gap of the caliper prior to a deceleration command.

[0008] Generally, brake control in ADAS control sends deceleration instructions from the ADAS to an electronic stability program (ESP, or vehicle dynamics control (VDC)) that controls the vehicle's behavior, and the ESP calculates a signal to control the brake device. When controlling the brake device via the ESP in this way, it is important to have a fail-safe in case the EPS temporarily malfunctions or the vehicle's behavior cannot be controlled due to a malfunction of the wheel speed sensor, etc.

[0009] The present invention aims to address such problems. That is, the present invention aims to improve responsiveness and enable precise brake control in the brake control of a driving assistance system such as ADAS, and to construct a system with redundancy that enables appropriate brake control even in a situation where the vehicle behavior cannot be controlled. [Means for solving the problem]

[0010] In order to solve such problems, the present invention has the following configuration. An automatic brake control device for a vehicle that controls a brake device as part of control of a driving assistance system, comprising a first electronic control device that controls the driving assistance system, and a plurality of electronic control devices that are communicatively connected to each other so that they can exchange information, characterized in that instructions sent from the first electronic control device to other electronic control devices to control the brake device include a first instruction for controlling the behavior of the vehicle and a second instruction having instruction content different from the first instruction. Effect of the Invention

[0011] In an automatic brake control device for a vehicle having such characteristics, a first electronic control device that controls a driving assistance system sends instructions for controlling the brake device to another electronic control device in two systems of instructions, a first instruction and a second instruction having different instruction content from the first instruction, so that the first instruction can be an instruction to control the behavior of the vehicle, such as a deceleration instruction, and the second instruction can be an instruction to directly operate the brake device, such as a hydraulic pressure instruction.

[0012] This enables more responsive and precise brake control in the control of driving assistance systems such as ADAS. It also makes it possible to build a system with redundancy that enables appropriate brake control even in situations where vehicle behavior cannot be controlled. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an explanatory diagram showing an automatic brake control device for a vehicle according to a first embodiment of the present invention. [Diagram 2] FIG. 5 is an explanatory diagram showing an automatic brake control device for a vehicle according to a second embodiment of the present invention. [Diagram 3] FIG. 11 is a sequence diagram showing the processing of each ECU in the second embodiment. [Figure 4] FIG. 4 is an explanatory diagram showing an intention information table. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, the same reference numerals in different drawings indicate parts having the same functions, and duplicated explanations in each drawing will be omitted as appropriate.

[0015] The vehicle automatic brake control device (hereinafter, automatic brake control device) 1 includes a plurality of electronic control units (hereinafter, ECUs). The plurality of ECUs are communicatively connected to each other via an in-vehicle network such as a Controller Area Network (CAN) so as to be able to exchange information.

[0016] In the first embodiment shown in Fig. 1, an automatic brake control device 1 that controls a brake device B includes an ECU (1) (first electronic control device) as a first ECU, and an ECU (2) as another ECU to which the ECU (1) transmits instructions related to brake control. The ECU (1) and ECU (2) here may be single ECUs, or may be composed of multiple ECUs linked to each other.

[0017] The ECU (1) is an ECU that controls the ADAS, and transmits instructions related to brake control to the ECU (2) according to various states of the ADAS control. At this time, the ECU (1) transmits a first instruction In1 and a second instruction In2 to the ECU (2). Here, the first instruction In1 is an instruction for controlling the behavior of the vehicle according to the control of the ADAS (e.g., a deceleration instruction), and the second instruction In2 is an instruction different in content from the first instruction In1 (e.g., an instruction related to a hydraulic pressure change for hydraulic circuit control of the brake device B).

[0018] In this way, the ECU (1) that performs ADAS control issues instructions related to brake control through two command systems, the first command In1 and the second command In2, so that the vehicle behavior can be controlled based on the first command In1, and the operation of the brake device that does not appear in the vehicle behavior, such as the operation of closing the brake caliper gap and the operation of compensating for the drop in hydraulic pressure after the EPB (Electronic Parking Brake) is activated, can be accurately performed by the second command In2. This allows the automatic brake control device 1 to perform brake control in ADAS control with high responsiveness, and also to perform precise control that is difficult to achieve with deceleration commands alone.

[0019] In the embodiment shown in Fig. 1, the ECU (2) (second electronic control unit) can be configured to include an ECU that controls the behavior of the vehicle, for example, an ESP. In this case, a deceleration command for controlling the vehicle behavior is issued as the first command In1, and the ESP performs vehicle behavior control to realize a request from the ADAS in response to the first command In1. When the ECU (2) includes an ESP, the second command In2 includes, in addition to a hydraulic pressure command for the brake device B, intention information on why the hydraulic pressure command was sent.

[0020] By including such intent information in the second instruction In2, the ESP can understand the intent behind the hydraulic pressure instruction issued by the ADAS when outputting a control signal for controlling the brake device B in accordance with the first instruction In1, and can appropriately output a control signal taking into account the hydraulic pressure instruction from the ADAS.

[0021] In the second embodiment shown in FIG. 2, the automatic brake control device 1 includes, as an ECU, ECU (3) (third electronic control device) in addition to ECU (1) and ECU (2). In this example, an instruction related to brake control from ECU (1) that controls the ADAS is sent to ECU (3) via ECU (2), and ECU (3) outputs a control signal to the brake device B. In this case, ECU (2) is an ECU (e.g., ESP) that controls the vehicle behavior as described above, and ECU (3) is an ECU that transmits a control signal to an electric booster of the brake device B, for example. Such a configuration is a system configuration that complies with the VDA (German Association of the Automotive Industry) standard.

[0022] At this time, the ECU (1) transmits instructions In21 and In22 as a first instruction In1 and a second instruction In2, respectively, to the other ECUs as instructions related to brake control. The first instruction In1 is an instruction for controlling the behavior of the vehicle (e.g., a deceleration instruction) and is transmitted to the ECU (2) (ESP). The instruction In21 is a hydraulic pressure instruction for controlling the hydraulic circuit of the brake device B and is transmitted to the ECU (3). The instruction In22 is intention information as to why the ECU (1) transmitted the hydraulic pressure instruction to the ECU (3) and is transmitted to the ECU (2).

[0023] In the system configuration of the embodiment shown in Fig. 2, when the ECU (1) transmits a deceleration command of a first command In1 to the ECU (2), the ECU (2) generates a command In3 (e.g., a command for a flow rate or the like for varying the hydraulic pressure of the brake device B) for the ECU (3) based on the first command In1. Then, the ECU (3) outputs a control signal (electric booster control signal) for controlling the brake device B in response to the command In3.

[0024] In response to this, the ECU (1) transmits a hydraulic pressure command, command In21, to the ECU (3) as necessary. When this command In21 is transmitted, the ECU (1) also transmits, to the ECU (2), intent information as to why the hydraulic pressure command, command In21, was transmitted. By transmitting this command In22, the ECU (2) can grasp the fact that the ECU (1) has directly transmitted a hydraulic pressure command to the ECU (3) and the intent behind it, and can generate command In3 taking into account the intent information.

[0025] Furthermore, when the hydraulic pressure command of command In21 is sent directly from ECU (1) to ECU (3), ECU (3) sends information In4 relating to the achievement status of the hydraulic pressure command of command In21 to ECU (2). This information In4 is information necessary for reconciling the hydraulic pressure command of command In21 and command In3, and current information on the current hydraulic pressure as a result of execution of command In21 and a predicted value of how many milliseconds it will take to reach the hydraulic pressure of command In21 are sent to ECU (2).

[0026] By transmitting this information In4, the ECU (2) can generate the command In3 taking into consideration the intention information of the command In22 and the information In4. In order to prevent the hydraulic command of the command In21 that the ECU (1) directly issues to the ECU (3) from interfering with the command In3 that the ECU (2) generates based on the deceleration command of the first command In1, it is preferable that the hydraulic command of the command In21 is an command that does not affect the behavior change of the vehicle or has a minimal effect on the behavior change of the vehicle. Specifically, the above-mentioned interference can be eliminated by limiting the hydraulic command of the command In21 to the range of the operation of the brake device that does not appear in the vehicle behavior (for example, the operation of closing the gap of the brake caliper or the operation of compensating for the drop in hydraulic pressure after the EPB (Electronic Parking Brake) is activated).

[0027] However, if the hydraulic pressure command of command In21 is sent with a high degree of urgency, the hydraulic pressure command of command In21 will take priority, and the brake device B will be controlled so that the hydraulic pressure of command In21 is immediately achieved, taking priority over the control of the vehicle behavior.

[0028] FIG. 3 is a sequence diagram showing an example of processing of one control cycle in each ECU in the second embodiment shown in FIG. 2. The ECU (1) that controls the ADAS judges whether to issue a hydraulic pressure command of the command In21 based on the state of the ADAS control and the output of various sensors in the ADAS (step S11). If it is judged that a hydraulic pressure command should be issued (step S11: YES), it calculates a target hydraulic pressure to be instructed according to the state (step S12) and transmits the hydraulic pressure value as the command In21 to the ECU (2) and the ECU (3). Then, if the command In21 is transmitted, the intention information on why the hydraulic pressure value was transmitted is selected from the intention information table as shown in FIG. 4 (step S13) and transmitted to the ECU (2) as the command In22. If it is judged that a hydraulic pressure command should not be issued in step S11 (step S11: NO), steps S12 and S13 are skipped and the current control cycle is terminated.

[0029] In parallel with step S11, the ECU (1) judges whether to issue a deceleration command of command In1 based on the ADAS control situation and the outputs of various sensors in the ADAS (step S14), and if it is judged that a deceleration command should be issued (step S14: YES), it calculates a target deceleration to be instructed according to the situation (step S15) and transmits the deceleration to the ECU (2) as command In1. Note that, if it is judged in step S14 that a deceleration command should not be issued (step S14: NO), step S15 is skipped and the current control cycle is ended.

[0030] As shown in Fig. 4, the intention information table stores information codes corresponding to the contents of the intention information in the memory of the ECU (1). In step S13, an information code is selected based on the conditions on which the target hydraulic pressure in step S12 is based in relation to the contents of the intention information in the intention information table, and the selected information code is transmitted to the ECU (2) as an instruction In22. As an example, if a target hydraulic pressure value of 0.2 MPa is transmitted in step S12, then in step S13, an information code corresponding to the target hydraulic pressure, for example, an information code of "0002", is transmitted to the ECU (2).

[0031] The processing of ECU(2) and ECU(3) when the first instruction In1 and the second instruction (instruction In21 and instruction In22) are transmitted from ECU(1) will be further explained with reference to FIG.

[0032] The ECU (2) receives the target hydraulic pressure value of the command In21 (step S21) and receives the intent information of the command In22 (step S22), thereby understanding that the hydraulic pressure command by the command In21 is given directly to the ECU (3). As a result, when a deceleration command is given by the first command In1, the ECU (2) does not immediately calculate the target flow rate (step S24), but performs arbitration processing (step S23), calculates the target flow rate in step S24 based on the arbitration result, and transmits the calculation result to the ECU (3) as the command In3.

[0033] When the ECU (3) receives the target hydraulic pressure value of the command In21 (step S31), it judges whether or not the target flow rate (previous value) has been received from the ECU (2) in the previous control cycle (step S32). If the target flow rate (previous value) has not been received in the previous control cycle (step S32: NO), the hydraulic pressure value received in step S31 becomes the initially received value of the command In21 of the ECU (1), and the ECU (3) obtains the target flow rate from this initially received value without waiting for the target flow rate to be received from the ECU (2), and outputs a discharge control command according to the target flow rate to the hydraulic circuit of the brake device B.

[0034] On the other hand, if it is determined in step S32 that the target flow rate (previous value) has been received from the ECU (2) in the previous control cycle, the control unit 10 waits for the target flow rate transmitted from the ECU (2) in the current control cycle to be received (step S33), and then outputs a discharge control instruction corresponding to the currently received target flow rate to the hydraulic circuit of the brake device B.

[0035] Then, when ECU (3) issues a discharge control command to brake device B (steps S35, S36), it transmits to ECU (2) as information In4 required for the above-mentioned arbitration, the current hydraulic pressure value (e.g., 0.1 MPa) achieved by the target hydraulic pressure (e.g., 0.2 MPa) according to command In21, the hydraulic pressure to be reached in the next control cycle (e.g., 0.15 MPa), and the like (step S35), and ends the current control cycle. ECU (2) receives this information In4 as information required for arbitration in the next control step (step S25).

[0036] In the arbitration in ECU (2) (step S23), arbitration is performed between the target deceleration sent from ECU (1) as the first command In1, the previous information In4 sent in step S35 to ECU (3) in the previous control cycle, the target hydraulic pressure value sent by command In21 in the current control cycle, and the intention information sent by command In22, and a target flow rate is calculated according to the arbitration result (step S24), and the result is sent to ECU (3) as the target flow rate value of command In3. After sending the target flow rate in step S24, ECU (2) receives information necessary for arbitration to be used in the next control cycle in step S25, and ends the current control cycle.

[0037] Thus, according to the automatic brake control device 1 according to the embodiment of the present invention, the brake control in the ADAS control can be performed by both the deceleration control suitable for controlling the vehicle behavior and the hydraulic pressure control capable of directly controlling the hydraulic circuit of the brake device. As a result, by optimizing the division of roles between the deceleration control and the hydraulic pressure control, the responsiveness of the brake control can be improved, and the actual accuracy of the vehicle behavior can be improved by precise control. In addition, by having two systems of instructions in the brake control, it is possible to build a system configuration that ensures redundancy.

[0038] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention includes design changes and the like that do not deviate from the gist of the present invention. In addition, the above-mentioned embodiments can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in the purpose, configuration, etc. [Explanation of symbols]

[0039] 1 Automatic brake control device In1 1st instruction In2 2nd instruction B Brake device

Claims

1. In an automatic brake control device for controlling a brake device in control of a driving assistance system, The vehicle includes a first electronic control unit that controls a driving assistance system, and includes a plurality of electronic control units that are communicatively connected to each other so as to be able to exchange information with each other; an instruction transmitted from the first electronic control unit to another electronic control unit for controlling the brake device includes a first instruction for controlling a behavior of the vehicle and a second instruction having an instruction content different from the first instruction, the first instruction is an instruction to decelerate the vehicle; 2. An automatic brake control device for a vehicle, wherein the second instruction is an instruction to change a hydraulic pressure of the brake device.

2. Another electronic control unit to which an instruction is sent from the first electronic control unit includes a second electronic control unit that controls a behavior of a vehicle, 2. The automatic brake control device for a vehicle according to claim 1, wherein the second instruction includes a hydraulic pressure instruction for the brake device and information on an intention for sending the hydraulic pressure instruction.

3. Another electronic control unit to which an instruction is sent from the first electronic control unit includes a third electronic control unit that controls the brake device, The first instruction is transmitted to the second electronic control unit; The second instruction is transmitted to the third electronic control unit as the hydraulic instruction and to the second electronic control unit as the intention information.

3. The automatic brake control device for a vehicle according to claim 2, wherein the second electronic control unit generates an instruction for the third electronic control unit based on the first instruction.

4. When the hydraulic pressure command of the second command is transmitted to the third electronic control device, 4. The automatic brake control device for a vehicle according to claim 3, wherein the third electronic control unit transmits information relating to the achievement status of the hydraulic pressure command to the second electronic control unit.

5. 5. The automatic brake control device for a vehicle according to claim 3, wherein the second instruction is an instruction that does not affect a change in behavior of the vehicle due to the first instruction or that has a reduced effect on the change in behavior of the vehicle.

6. The second electronic control unit is an electronic control unit for an electronic stability program (ESP), 6. The automatic brake control device for a vehicle according to claim 3, wherein the third electronic control device is an electronic control device that transmits a control signal to an electric booster of the brake device.

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