Deceleration control device

Abstract

To provide a deceleration control device that can perform deceleration control of an EDSS, without requiring a brake system corresponding to an external deceleration request.SOLUTION: A deceleration control device 1 is provided with: a valve 23 that is brought into an open state to supply compressed air to a brake mechanism and is brought into a close state so as not to supply compressed air to the brake mechanism; a sensor 26 that detects air pressure of the compressed air supplied to the brake mechanism; a brake indication obtaining part 11 that obtains a brake indication signal for deceleration control; an air pressure obtaining part 12 that obtains air pressure from the sensor 26; and a valve control part 13 that controls the valve into either of the open state and the close state. The valve control part 13 starts deceleration control when the brake indication signal is obtained, and in the deceleration control, controls the valve into the close state when the air pressure is above a predetermined first threshold, and controls the valve into the open state when the air pressure is below a predetermined second threshold smaller than the first threshold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a deceleration control device that performs deceleration control to decelerate and stop a vehicle when a driver malfunctions. [Background technology]

[0002] An Emergency Driving Stop System (EDSS) is a technology for decelerating and stopping a vehicle when the driver is abnormal. For example, Patent Document 1 discloses a device that, in deceleration control using the EDSS, executes stop control to stop the vehicle by applying a braking force to the vehicle when the driver is in an abnormal state, and stop maintenance control to maintain the vehicle in a stopped state after the vehicle has been stopped by the stop control. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-1456 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional EDSS systems, when the ECU that controls the EDSS receives information that a switch installed in the driver's seat or passenger seats has been operated, it sends an external deceleration request, including a deceleration instruction value, to the brake ECU that controls the service brakes, and the brake ECU then controls the brakes in accordance with the external deceleration request to perform deceleration control.This mechanism is based on the premise that the brake ECU is capable of performing deceleration control by precisely controlling the current supplied to the valves that operate the brakes in accordance with the external deceleration request, and brake systems that perform deceleration control in accordance with such external deceleration requests are not necessarily installed in vehicles.

[0005] Therefore, an object of the present invention is to enable deceleration control of an EDSS without requiring a brake system that responds to external deceleration requests. [Means for solving the problem]

[0006] A deceleration control device according to a first aspect of the present invention is a deceleration control device that performs deceleration control to slow down and stop a vehicle in the event of a driver abnormality, and includes: a valve that is provided in a compressed air flow path for driving a brake mechanism, and that supplies compressed air to the brake mechanism when opened and stops supplying compressed air to the brake mechanism when closed; a sensor that detects the air pressure, which is the pressure of the compressed air supplied to the brake mechanism through the valve; a brake instruction acquisition unit that acquires a brake instruction signal indicating that a predetermined switch for performing deceleration control has been operated; an air pressure acquisition unit that acquires the air pressure from the sensor; and a valve control unit that controls the valve to either an open state or a closed state, wherein the valve control unit starts deceleration control when the brake instruction signal is acquired, and in the deceleration control, controls the valve to a closed state when the air pressure becomes equal to or greater than a predetermined first threshold, and controls the valve to an open state when the air pressure becomes equal to or less than a predetermined second threshold that is smaller than the first threshold.

[0007] In this aspect, when the air pressure of the compressed air is equal to or lower than the second threshold, the valve supplying compressed air to the brake mechanism is controlled to an open state, and when the air pressure of the compressed air is equal to or higher than the first threshold, the valve supplying compressed air to the brake mechanism is controlled to a closed state, thereby maintaining the air pressure between the first threshold and the second threshold. The vehicle is then decelerated by the deceleration generated by the brake mechanism according to the air pressure maintained between the first and second thresholds. Therefore, desired deceleration control can be achieved by simply controlling the valve to either an open state or a closed state. Furthermore, because deceleration control is achieved by controlling the air pressure of a single system of compressed air, the configuration for supplying compressed air can be simplified.

[0008] In the deceleration control device of the second aspect, in the deceleration control device of the first aspect, the valve control unit may send to the valve either a first signal for controlling the valve to an open state or a second signal for controlling the valve to a closed state, and may be configured to send a second signal to the valve when the air pressure becomes equal to or greater than a first threshold while sending the first signal, and to send the first signal to the valve when the air pressure becomes equal to or less than the second threshold while sending the second signal.

[0009] According to this aspect, the valve can be controlled to either an open state or a closed state by sending either the first signal or the second signal to the valve, thereby easily realizing deceleration control.

[0010] In the deceleration control device according to the third aspect, in the deceleration control device according to the second aspect, the valve may be in an open state when current is supplied and in a closed state when current is not supplied, and the valve control unit may supply current to the valve as a first signal and not supply current to the valve as a second signal.

[0011] According to this aspect, the first signal or the second signal is transmitted by supplying or not supplying current, which makes it easy to control the opening and closing of the valve.

[0012] In the deceleration control device according to the fourth aspect, in the deceleration control device according to any one of the first to third aspects, the first threshold value may be greater than a given target value for air pressure, and the second threshold value may be smaller than the target value.

[0013] According to this aspect, the air pressure is controlled to be close to the target value. By setting the target value to an air pressure that generates a desired deceleration, suitable deceleration control is achieved.

[0014] In a deceleration control device according to a fifth aspect, in the deceleration control device according to any one of the first to fourth aspects, the valve control section may maintain the valve in an open state after the vehicle comes to a stop.

[0015] According to this aspect, it is possible to maintain the vehicle in a stopped state after the deceleration control ends without requiring a separate control system and air supply system.

[0016] In a deceleration control device according to a sixth aspect, in the deceleration control device according to any one of the first to fourth aspects, the valve control unit may control the valve to a closed state when the air pressure becomes equal to or greater than a first threshold after the vehicle has stopped, and control the valve to an open state when the air pressure becomes equal to or less than a second threshold.

[0017] According to this aspect, it is possible to maintain the vehicle in a stopped state by maintaining the air pressure within a desired range even after the deceleration control is completed, without requiring a separate control system or air supply system. [Effects of the Invention]

[0018] According to one aspect of the present invention, deceleration control of an EDSS is possible without requiring a brake system that responds to external deceleration requests. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a block diagram showing a functional configuration of a deceleration control device according to an embodiment of the present invention; [Figure 2] 4 is a flowchart showing a deceleration control process performed by the deceleration control device of the present embodiment. [Figure 3] FIG. 10 is a diagram showing an example of changes in a valve control signal according to air pressure. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements will be designated by the same reference numerals, and redundant description will be omitted.

[0021] 1 is a block diagram showing the functional configuration of a deceleration control device according to one embodiment of the present invention. The deceleration control device 1 is mounted on a vehicle and performs deceleration control to decelerate and stop the vehicle when the driver is abnormal. In other words, the deceleration control device constitutes an EDSS.

[0022] The deceleration control device 1 includes a control device 10. The control device 10 is configured, for example, by an ECU (Electronic Control Unit). The control device 10 configured by the ECU may be configured as an electronic control unit having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a CAN (Controller Area Network) communication circuit, etc. The control device 10 realizes various functions by, for example, loading a program stored in the ROM into the RAM via the CAN communication circuit and executing the program loaded into the RAM by the CPU. The control device 10 may be configured by multiple electronic control units, and may include, for example, an ASIC (Application Specific Integrated Circuit), a microprocessor (microcomputer), a DSP (Digital Signal Processor), etc.

[0023] The control device 10 is configured, for example, by an ECU for the EDSS (EDSS-ECU), and functionally includes a brake command acquisition unit 11, an air pressure acquisition unit 12, and a valve control unit 13. The functions of the control device 10 will be described in detail later.

[0024] In addition to the control device 10, the deceleration control device 1 is equipped with an emergency brake switch (driver's seat) 21, an emergency brake switch (inside passenger seat) 22, a valve 23, an air tank 24, a pressure reducing valve 25, an air pressure sensor 26, a DC (double check) valve 27, a service brake circuit 28, a horn 29, a flasher 30, a brake switch indicator 31, and an air pressure sensor 32.

[0025] The emergency brake switch (driver's seat) 21 is provided at the driver's seat and is a switch for starting deceleration control in the EDSS. The emergency brake switch (driver's seat) 21 is configured to be, for example, depressible, and sends a brake instruction signal to the control device 10 in response to a depressing operation by the driver or the like.

[0026] The emergency brake switch (inside passenger seat) 22 is provided in a passenger seat inside the vehicle and is a switch for starting deceleration control in the EDSS. The emergency brake switch (inside passenger seat) 21 is configured to be, for example, pressable, and sends a brake instruction signal to the control device 10 in response to a pressing operation by a passenger or the like.

[0027] Valve 23 is provided in a flow path of compressed air for driving the brake mechanism, and when opened, supplies compressed air to the brake mechanism, and when closed, does not supply compressed air to the brake mechanism.

[0028] The valve 23 is controlled to an open state and a closed state by a first signal and a second signal, respectively, sent from the control device 10. The valve 23 may acquire a state in which current is being supplied from the control device 10 as the first signal, and may acquire a state in which current is not being supplied as the second signal.

[0029] The air tank 24 stores compressed air and is a source of compressed air for the valve 23, the DC valve 27, and the service brake circuit 28.

[0030] The pressure reducing valve 25 reduces the pressure of the compressed air from the air tank 24 to a predetermined pressure, and supplies the compressed air at the predetermined pressure to the valve 23 .

[0031] The air pressure sensor 26 is a sensor that detects the air pressure, which is the pressure of compressed air supplied to the brake mechanism via the valve 23. The air pressure sensor 26 sends the detected air pressure to the control device 10.

[0032] The DC valve 27, the service brake circuit 28, and the air pressure sensor 32 constitute an example of a brake mechanism in this embodiment. The DC valve 27 is a valve that receives compressed air supplied via the valve 23 and compressed air supplied from a separate service brake air supply path (not shown), and sends the compressed air with the higher pressure of the two input compressed air systems to the service brake circuit 28.

[0033] The service brake circuit 28 includes a control circuit that controls the vehicle's normal brakes in response to compressed air supplied via the DC valve 27. The brake mechanism including the DC valve 27 and the service brake circuit 28 generates deceleration in the vehicle in response to the air pressure of the compressed air supplied in response to the opening and closing of the valve 23.

[0034] The air pressure sensor 32 is a sensor that detects the pressure of compressed air supplied to the service brake circuit 28 via the DC valve 27. The air pressure sensor 32 sends the detected air pressure to the control device 10. The control device 10 can determine whether or not there is an abnormality in the supply of compressed air to the service brake circuit 28, for example, by comparing the detection value obtained from the air pressure sensor 32 with the air pressure detected by the air pressure sensor 26.

[0035] The horn 29 is a device that emits an alarm sound outside the vehicle, and when deceleration control is performed by the EDSS, the alarm sound is emitted to notify the surrounding area that an abnormality has occurred.

[0036] The flashers 30 are lamps provided inside and / or outside the vehicle, and when deceleration control is being performed by the EDSS, they flash, for example, to alert passengers inside the vehicle and / or outside the vehicle that an abnormality has occurred.

[0037] The brake switch indicator 31 is a device that is provided inside the vehicle and that displays, lights up, or flashes to let the driver and / or passengers know that deceleration control by the EDSS is being performed.

[0038] Next, a description will be given of each functional unit of the control device 10. The brake instruction acquisition unit 11 acquires a brake instruction signal indicating that a predetermined switch for executing deceleration control has been operated. In this embodiment, the brake instruction acquisition unit 11 acquires a brake instruction signal sent from an emergency brake switch (driver's seat) 21 or an emergency brake switch (inside passenger seats) 22.

[0039] The air pressure acquisition unit 12 acquires the air pressure from a sensor. In this embodiment, the air pressure acquisition unit 12 acquires the air pressure of the compressed air supplied from the valve 23 to the DC valve 27, which is acquired by the air pressure sensor 26.

[0040] The valve control unit 13 controls the valve 23 to either an open state or a closed state. When the brake instruction acquisition unit 11 acquires a brake instruction signal, the valve control unit 13 of this embodiment starts deceleration control in the EDSS.

[0041] During deceleration control, the valve control unit 13 controls the valve 23 to a closed state when the air pressure is equal to or greater than a predetermined first threshold, and controls the valve to an open state when the air pressure is equal to or less than a predetermined second threshold that is lower than the first threshold. By controlling the valve to an open or closed state in this manner, the air pressure is maintained between the first and second thresholds during deceleration control. The vehicle is then decelerated by the deceleration generated by the brake mechanism in accordance with the air pressure maintained between the first and second thresholds.

[0042] The first threshold is set to a value greater than a given target value, and the second threshold is set to a value less than the target value. By setting the first and second thresholds in this manner, the air pressure is controlled to be close to the target value. By setting the air pressure that generates a desired deceleration as the target value, suitable deceleration control is achieved. For example, if a suitable deceleration is generated in the brake mechanism (DC valve 27, service brake circuit 28) when the air pressure is 2.5 bar, the first threshold can be set to 2.6 bar and the second threshold to 2.4 bar, thereby making it possible to maintain the air pressure at 2.4 bar to 2.6 bar, which is close to 2.5 bar.

[0043] The valve control unit 13 may send either a first signal for controlling the valve 23 to an open state or a second signal for controlling the valve 23 to a closed state as a control signal to the valve 23. When the valve 23 receives the first signal, the valve 23 is controlled to an open state, and when the valve control unit 13 receives the second signal, the valve 23 is controlled to a closed state. The first signal is a so-called ON signal for opening the valve 23, and the second signal is a so-called OFF signal for closing the valve 23.

[0044] As deceleration control in the EDSS, the valve control unit 13 sends a first signal to the valve 23 when the air pressure becomes equal to or greater than a first threshold, and sends a second signal to the valve 23 when the air pressure becomes equal to or less than a second threshold while sending a second signal. In this way, the valve control unit 13 can control the valve to either an open state or a closed state by sending either the first signal or the second signal to the valve 23. This makes it possible to easily achieve deceleration control.

[0045] Valve 23 may be in an open state when current is supplied, and in a closed state when current is not supplied. That is, valve 23 may recognize a state in which current is supplied as an ON signal, and a state in which current is not supplied as an OFF signal. In this case, valve control unit 13 supplies current to valve 23 as a first signal, and does not supply current to valve 23 as a second signal. In this way, supplying or not supplying current realizes the transmission of the first signal or the second signal, so valve control unit 13 can easily control the opening and closing of the valve.

[0046] Furthermore, after the deceleration control is completed, i.e., after the vehicle has stopped, the valve control unit 13 may maintain the vehicle in a stopped state by maintaining the valve 23 in an open state. This type of control makes it possible to maintain the vehicle in a stopped state after the deceleration control is completed without requiring a separate control system and air supply system.

[0047] Furthermore, after the end of deceleration control, the valve control unit 13 may control the valve 23 to the closed state when the air pressure becomes equal to or greater than the first threshold, as was the case before the end of deceleration control, and control the valve to the open state when the air pressure becomes equal to or less than the second threshold, thereby maintaining the vehicle in a stopped state. This type of control makes it possible to maintain the vehicle in a stopped state by maintaining the air pressure within a desired range even after the end of deceleration control, without requiring a separate control system and air supply system.

[0048] Next, the deceleration control process performed by the deceleration control device 1 of this embodiment will be described with reference to Figures 2 and 3. Figure 2 is a flowchart showing the deceleration control process. Figure 3 is a diagram showing an example of changes in the valve control signal according to the air pressure.

[0049] In step S1, the brake instruction acquisition unit 11 determines whether or not an emergency brake instruction has been acquired. If it is determined that an emergency brake instruction has been acquired, the process proceeds to step S2. If it is not determined that an emergency brake instruction has been acquired, the process of step S1 is repeated, and monitoring of the emergency brake instruction continues.

[0050] In step S2, the valve control unit 13 starts deceleration control. When deceleration control starts, the valve 23 is normally in a closed state, so in step S3, the valve control unit 13 sends a first signal to the valve 23. Upon receiving the first signal, the valve 23 is controlled to an open state. Then, the vehicle is decelerated by the deceleration generated by the brake mechanism in accordance with the air pressure of the compressed air supplied from the valve 23.

[0051] In step S4, the valve control unit 13 determines whether the vehicle has stopped. That is, it determines whether or not deceleration control can be ended. The valve control unit 13 may recognize that the vehicle has stopped based on a vehicle speed sensor and other predetermined control signals. If it is determined that the vehicle has stopped, the process proceeds to step S9. On the other hand, if it is not determined that the vehicle has stopped, the process proceeds to step S5.

[0052] In step S5, the valve control unit 13 determines whether the air pressure acquired by the air pressure acquisition unit 12 has reached the first threshold. If it is determined that the air pressure has reached the first threshold, the process proceeds to step S6. On the other hand, if it is determined that the air pressure has not reached the first threshold, the process proceeds to step S4.

[0053] In step S6, the valve control unit 13 sends a second signal to the valve 23. Upon receiving the second signal, the valve 23 is controlled to a closed state, thereby stopping the supply of compressed air to the brake mechanism.

[0054] In step S7, the valve control unit 13 determines whether the vehicle has stopped. That is, it determines whether or not the deceleration control can be ended. If it is determined that the vehicle has stopped, the process proceeds to step S9. On the other hand, if it is not determined that the vehicle has stopped, the process proceeds to step S8.

[0055] In step S8, the valve control unit 13 determines whether the air pressure acquired by the air pressure acquisition unit 12 has dropped to the second threshold value. If it is determined that the air pressure has dropped to the second threshold value, the process proceeds to step S3. On the other hand, if it is not determined that the air pressure has dropped to the second threshold value, the process proceeds to step S7.

[0056] If it is determined in step S4 or step S7 that the vehicle has stopped, the deceleration control ends in step S9.

[0057] 3 shows the transition of the valve control signal sent by the valve control unit 13 to the valve 23 and the change in air pressure acquired by the air pressure sensor 26 in steps S3 to S8 and S9. That is, when an ON signal (first signal) is sent from the valve control unit 13 (S3), the valve 23 is controlled to an open state, so that the air pressure increases. Subsequently, when the increased air pressure reaches a first threshold value (S5), the valve control unit 13 sends an OFF signal (second signal) (S6). In response to the sending of the OFF signal, the valve 23 is controlled to a closed state, so that the air pressure decreases. When the decreased air pressure falls to a second threshold value (S8), the valve control unit 13 again sends an ON signal (S3). By repeating the processing of steps S3, S5, S6, and S8, the vehicle is decelerated by the deceleration generated by the brake mechanism according to the air pressure maintained between the first threshold and the second threshold, and when the vehicle has stopped as indicated by the stop flag (S4 or S7), the deceleration control is terminated (S9). Note that the stop flag is an example of a control signal that indicates the state of the vehicle, and is a signal that is set when it is recognized that the vehicle is in a stopped state based on the vehicle speed sensor and other predetermined control signals, and is not necessarily provided in the deceleration control device 1.

[0058] In step S10, the control device 10 performs vehicle braking and maintenance. Specifically, as shown by the solid line in the graph of the valve control signal and air pressure sensor value in FIG. 3, the valve control unit 13 may maintain the valve 23 in an open state by continuing to send a first signal to the valve 23, thereby maintaining the vehicle in a stopped state. This makes it possible to maintain the vehicle in a stopped state after the end of deceleration control without requiring a separate control system or air supply system. Specifically, the valve control unit 13 may maintain the sending of the first signal when it recognizes that the vehicle is stopped based on a vehicle speed sensor, other predetermined control signals, the above-mentioned stop flag, etc.

[0059] 3, the valve control unit 13 may control the valve 23 to the closed state when the air pressure becomes equal to or greater than the first threshold, and to the open state when the air pressure becomes equal to or less than the second threshold, as was done before the deceleration control was terminated, thereby maintaining the vehicle in a stopped state. This control makes it possible to maintain the vehicle in a stopped state by maintaining the air pressure within a desired range even after the deceleration control is terminated, without requiring a separate control system or air supply system.

[0060] In step S11, the control device 10 determines whether the key has been turned off. If it is determined that the key has been turned off, the deceleration control process ends. On the other hand, if it is not determined that the key has been turned off, the process for maintaining braking in step S10 is repeated.

[0061] As described above, in the deceleration control device 1 of this embodiment, when the air pressure of the compressed air is equal to or lower than the second threshold, the valve 23 that supplies compressed air to the brake mechanism is controlled to an open state. When the air pressure of the compressed air is equal to or higher than the first threshold, the valve 23 that supplies compressed air to the brake mechanism is controlled to a closed state. This maintains the air pressure between the first and second thresholds. The vehicle is then decelerated by the deceleration generated by the brake mechanism according to the air pressure maintained between the first and second thresholds. Therefore, desired deceleration control can be achieved by simply controlling the valve to either an open state or a closed state. Furthermore, because deceleration control is achieved by controlling the air pressure of a single system of compressed air, the configuration for supplying compressed air can be simplified.

[0062] The present invention has been described in detail above based on the embodiments. However, the present invention is not limited to the above embodiments. Various modifications can be made to the present invention without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0063] 1...deceleration control device, 10...control device, 11...brake command acquisition unit, 12...air pressure acquisition unit, 13...valve control unit, 23...valve, 24...air tank, 25...pressure reducing valve, 26...air pressure sensor, 27...DC valve, 28...service brake circuit, 29...horn, 30...flasher, 31...brake switch indicator, 32...air pressure sensor.

Claims

1. A deceleration control device that performs deceleration control to decelerate and stop a vehicle when a driver is abnormal, a valve that is provided in a flow path of compressed air for driving a brake mechanism, the valve supplying the compressed air to the brake mechanism when opened and not supplying the compressed air to the brake mechanism when closed; a sensor for detecting an air pressure, which is the pressure of the compressed air supplied to the brake mechanism via the valve; a brake instruction acquisition unit that acquires a brake instruction signal indicating that a predetermined switch for executing the deceleration control has been operated; an air pressure acquisition unit that acquires the air pressure from the sensor; a valve control unit that controls the valve to either an open state or a closed state, The valve control unit When the brake instruction signal is acquired, the deceleration control is started. In the deceleration control, When the air pressure reaches or exceeds a predetermined first threshold, the valve is controlled to a closed state; When the air pressure becomes equal to or less than a predetermined second threshold value that is smaller than the first threshold value, the valve is controlled to an open state; the valve control unit controls the valve to a closed state when the air pressure becomes equal to or higher than the first threshold after the vehicle has stopped, and controls the valve to an open state when the air pressure becomes equal to or lower than the second threshold. Deceleration control device.

2. the valve control unit sends to the valve either a first signal for controlling the valve to an open state or a second signal for controlling the valve to a closed state; while transmitting the first signal, when the air pressure becomes equal to or greater than the first threshold, transmitting the second signal to the valve; while transmitting the second signal, when the air pressure becomes equal to or lower than the second threshold, transmitting the first signal to the valve; The deceleration control device according to claim 1 .

3. The valve is in an open state when current is supplied thereto and in a closed state when current is not supplied thereto; the valve control unit supplies current to the valve as the first signal and does not supply current to the valve as the second signal; The deceleration control device according to claim 2 .

4. the first threshold is greater than a given target value for air pressure; The second threshold value is smaller than the target value. The deceleration control device according to any one of claims 1 to 3.

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