JP5746495B2 - Brake control device - Google Patents

Description

  The present invention relates to a brake control device that controls the operation of a brake device that generates a servo force using an electric motor as a drive source.

  For example, as described in Patent Document 1, in a brake control device provided with an electric booster that uses an electric motor as a drive source, even if the main power supply fails, the braking function is maintained using an auxiliary power supply. What is made is known. In this brake control device, when a failure occurs in a component such as a sensor or an electric motor, failure diagnosis information is stored so that the cause of the failure can be identified afterwards at a repair shop or the like. At this time, the failure diagnosis information is written to a volatile memory such as a RAM at any time when a failure occurs, and the failure diagnosis information written to the volatile memory when the control system is shut down is a nonvolatile memory such as an EEPROM. A process of writing to the memory is performed.

International Publication No. 2010/113574

  As described above, in the conventional brake control device having a failure diagnosis function, when switching to the auxiliary power source is executed due to a failure of the main power source, the capacity of the auxiliary power source is small, so depending on the operating condition of the brake device, the time may be short. Therefore, there is a case where the power supply by the auxiliary power supply becomes impossible. However, it is very difficult to predict the exact duration of the auxiliary power supply. If power supply by the auxiliary power supply is inadvertently cut off, the fault diagnosis information written in the volatile memory is Will be lost. In addition, if power supply is interrupted during writing to the nonvolatile memory, the nonvolatile memory itself may be damaged.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a brake control device that improves the reliability of the process of writing failure diagnosis information to a nonvolatile memory.

In order to solve the above problems, the present invention controls a master cylinder that generates brake fluid pressure by propulsion of a piston, an electric motor that drives the piston, and an operation of the electric motor in accordance with an operation of a brake pedal. And a main power source and an auxiliary power source that supply power to the electric motor and the control device, and the control device normally supplies power to the control device and the electric motor by a main power source. In the brake control device that executes an auxiliary power mode in which power is supplied to the control device and the electric motor by the auxiliary power when the mode is executed and an abnormality on the main power source is detected, the control device includes the brake When a failure of the control device is detected, the failure diagnosis information is written in the volatile memory, and when executing a predetermined control end process, Immediately after the power supply by the auxiliary power supply is started when the main power supply mode is changed to the auxiliary power supply mode, and has a fault diagnosis function for writing the fault diagnosis information written in the volatile memory to the nonvolatile memory. In addition, the failure diagnosis information written in the volatile memory is written in the nonvolatile memory, and when the power that can be supplied from the auxiliary power source falls below a predetermined power during the execution of the auxiliary power mode, the fault diagnosis information is written to the electric motor. The failure diagnosis information written in the volatile memory is written again in the nonvolatile memory.

  According to the brake control device of the present invention, it is possible to improve the reliability of the process of writing the failure diagnosis information to the nonvolatile memory.

It is a figure showing the whole brake control device composition concerning one embodiment of the present invention. It is a circuit diagram which shows schematic structure of the master pressure control apparatus of the brake control apparatus shown in FIG. It is a flowchart which shows the write-in process to the non-volatile memory of the failure diagnosis information in the brake control apparatus shown in FIG.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an overall configuration of a brake control device 1 according to the present embodiment. In the figure, a broken line with an arrow is a signal line, and a signal flow is represented by the direction of the arrow. The brake control device 1 electrically connects the master pressure control mechanism 4 including the master cylinder 9 and the electric motor 20 for controlling the master pressure that is the brake fluid pressure generated by the master cylinder 9. A master pressure control device 3 that is a control device for controlling the wheel, a wheel pressure control mechanism 6 that supplies brake fluid pressure to the brake device of each wheel, and a wheel pressure for electrically controlling the wheel pressure control mechanism 6. The controller 5 includes an input rod 7, an operation amount detector 8, a reservoir tank 10, a vehicle power source E that is a main power source, and an auxiliary power source 12.

  And as a 1st pressure increase / decrease part for generating hydraulic pressure with the master cylinder 9, it is provided in the master cylinder 9 side of the input rod 7 which moves by operation of the brake pedal 100, and the input rod 7, An input piston 16 that controls the pressure of the primary liquid chamber 42 is provided. Further, as a second pressure increasing / decreasing unit for generating a hydraulic pressure in the master cylinder 9, a master pressure control device 3, a master pressure control mechanism 4, and an assist piston 40 controlled by the master pressure control mechanism 4 are provided. It has been. As will be described later, the input piston 16 and the assist piston 40 act as a primary piston that is a piston that controls the fluid pressure in the primary fluid chamber 42 of the master cylinder 9.

  The input piston 16 and the assist piston 40 are provided so as to be relatively movable in the axial direction, and a pair of neutral springs 19A and 19B are interposed therebetween. The input piston 16 and the assist piston 40 are elastically held at a certain neutral position by the spring force of the neutral springs 19A and 19B, and the spring force of the neutral springs 19A and 19B acts on the relative displacement in the axial direction. .

  The master pressure control device 3 and the wheel pressure control device 5 perform two-way communication and share a control command and a vehicle state quantity. The vehicle state quantity is, for example, a value or data representing a yaw rate, longitudinal acceleration, lateral acceleration, steering angle, wheel speed, vehicle body speed, failure diagnosis information, operating state, and the like.

  The master pressure control device 3 for performing the brake control is operated by the electric power supplied from the vehicle power source E, and controls the operation of the electric motor 20 based on the brake operation amount that is the detection value of the operation amount detection device 8. . Here, the vehicle power source E indicates an in-vehicle battery and a vehicle generator, and in the case of a general conventional vehicle, an alternator and a battery, and in the case of a so-called hybrid vehicle or electric vehicle, a high voltage A DC / DC converter and a low voltage battery for converting voltage from a power source to a low voltage power source such as a 12 volt system or a 24 volt system are shown. The master pressure control mechanism 4 is a mechanism that presses the assist piston 40 in accordance with the motor drive current output from the master pressure control device 3, and amplifies the rotation torque of the electric motor 20 that generates rotation torque. And a rotation-linear motion conversion device 25 that performs mutual conversion between rotational motion and linear motion.

  The wheel pressure control device 5 is operated by the electric power supplied from the vehicle power supply E, and controls the anti-lock brake control function for preventing each wheel from locking, and controls the brake fluid pressure supplied to each wheel, thereby preventing understeer and It has a vehicle behavior stabilization control function that suppresses oversteer and stabilizes the behavior of the vehicle, etc., calculates the target braking force to be generated at each wheel based on the vehicle state quantity, and based on this calculated value The wheel pressure control mechanism 6 is controlled. The wheel pressure control mechanism 6 receives the brake fluid pressurized by the master cylinder 9 in accordance with the output of the wheel pressure control device 5, and each hydraulic brake device 11 a to 11 d for generating a friction braking force on each wheel. Control the hydraulic pressure of the brake fluid supplied to

  The input rod 7 is connected to the brake pedal 100 and drives the input piston 16 whose other end is inserted into the primary fluid chamber 42. By adopting such a configuration, it is possible to increase the master pressure even by a driver's braking operation. Therefore, even if the electric motor 20 becomes inoperable, a braking force can be generated. A reaction force corresponding to the master pressure acts on the brake pedal 100 via the input rod 7 and is transmitted to the driver as a brake pedal reaction force.

  The operation amount detection device 8 includes at least one sensor that detects a required brake force from a driver's pedal operation amount. Further, as the sensor used here, a displacement sensor that detects the movement angle of the brake pedal 100 or the movement amount of the input rod 7 may be used, or a pedal force sensor that detects the pedal force of the brake pedal 100 may be used. Alternatively, master pressure sensors 56 and 57 for detecting the fluid pressure in the master cylinder 9 may be used. In addition, the sensor configuration of the operation amount detection device 8 may be a configuration in which at least two different types of sensors such as a displacement sensor, a pedaling force sensor, and a master pressure sensor are combined.

  The master cylinder 9 is of a tandem type having two pressure chambers, a primary liquid chamber 42 pressurized by the assist piston 40 and a secondary liquid chamber 43 pressurized by the secondary piston 41. The brake fluid pressurized in each pressurizing chamber by the assist piston 40 and the input piston 16 is supplied to the wheel pressure control mechanism 6 via the master pipes 102a and 102b. The reservoir tank 10 is connected to the primary liquid chamber 42 and the secondary liquid chamber 43 through a reservoir port. The reservoir port is opened when the assist piston 40 and the secondary piston 41 are in the retracted position, and the primary fluid chamber 42 and the secondary fluid chamber 43 are connected to the reservoir tank 10 to appropriately replenish the brake fluid. When 41 advances, it closes and the primary liquid chamber 42 and the secondary liquid chamber 43 can be pressurized.

  The hydraulic brake devices 11a to 11d include a cylinder, a piston, a brake pad, and the like (not shown). The piston is propelled by the brake hydraulic pressure supplied from the wheel pressure control mechanism 6, and a brake pad connected to the piston is provided. The disc rotors 101a to 101d are pressed to generate a friction braking force. Since the disc rotors 101a to 101d rotate integrally with the wheels, the brake torque acting on the disc rotors 101a to 101d becomes a braking force acting between the wheels and the road surface. In the figure, the FL wheel indicates the left front wheel, the FR wheel indicates the right front wheel, the RL wheel indicates the left rear wheel, and the RR wheel indicates the right rear wheel.

  The auxiliary power supply 12 stores electric power and can supply electric power to the master pressure control device 3 when the vehicle power supply E fails, and it is appropriate to use a capacitor from the viewpoint of reliability. In addition, a small battery or a separate vehicle power source may be used, but in any case, the auxiliary power source 12 can be supplied in comparison with a vehicle power source E that is a main power source that originally supplies power to the master pressure control device 3. The amount of power is low.

  Next, the configuration and operation of the master pressure control mechanism 4 will be described. The electric motor 20 is operated by a motor driving current controlled by the master pressure control device 3, and generates a desired rotational torque. For example, a DC motor, a DC brushless motor, an AC motor, or the like can be used as the electric motor 20, but a DC brushless motor is desirable in terms of controllability, silence, and durability. The electric motor 20 is provided with a rotation angle detection sensor 205 such as a resolver, for example, and this signal is input to the master pressure control device 3. Thereby, the master pressure control device 3 can calculate the rotation angle, that is, the rotation amount of the electric motor 20 based on the signal of the rotation angle detection sensor 205, and the propulsion amount of the rotation-linear motion conversion device 25 based on this. That is, the displacement amount of the assist piston 40 can be calculated.

  The reduction gear 21 amplifies the rotational torque of the electric motor 20 by the reduction ratio. As a speed reduction method, for example, a gear speed reduction, a pulley speed reduction, or the like can be used. In this embodiment, a speed reduction method using a driving pulley 22, a driven pulley 23, and a belt 24 is employed. . When the rotational torque of the electric motor 20 is sufficiently large and it is not necessary to amplify the torque by deceleration, it is possible to directly connect the electric motor 20 and the rotation / linear motion conversion device 25 without providing the reduction gear 21. . Thereby, it can be expected to avoid various problems related to reliability, silence, and mountability caused by the intervention of the reduction gear.

  The rotation / linear motion conversion device 25 converts the rotational motion of the electric motor 20 into a linear motion and drives the assist piston 40. As the conversion mechanism, for example, a rack and pinion, a ball screw, or the like can be used. In this embodiment, a system using a ball screw is employed. In this ball screw system, a driven pulley 23 is fitted to the outside of the ball screw nut 26, and the ball screw shaft 27 moves linearly along the axis by the rotation of the ball screw nut 26 due to the rotation, and this thrust As a result, the assist piston 40 is pressed via the movable member 28.

  The movable member 28 is engaged with the other end of a return spring 29 supported at one end by a fixed portion of the housing, and a force in a direction opposite to the thrust of the ball screw shaft 27 is applied to the ball screw shaft 27 via the movable member 28. It is configured to work. As a result, even when braking, that is, when the assist piston 40 is pressed to pressurize the primary fluid chamber 42, the electric motor 20 becomes inoperable and the return control of the ball screw shaft 27 becomes impossible. Since the ball screw shaft 27 is returned to the initial position by the spring force of the spring 29 and the master pressure is reduced to nearly zero, it is possible to prevent the vehicle behavior from becoming unstable due to the drag of the brake.

  Next, amplification of the thrust of the input rod 7 will be described. Since the thrust of the assist piston 40 is applied according to the thrust of the input rod 7 by displacing the assist piston 40 according to the displacement amount of the input piston 16 via the input rod 7 by the driver's brake operation, the input The primary liquid chamber 42 is pressurized so that the thrust of the rod 7 is amplified. The amplification ratio (hereinafter referred to as “boost ratio”) can be arbitrarily set by the relative displacement between the input rod 7 and the assist piston 40, the ratio of the cross-sectional areas of the input piston 16 and the assist piston 40, and the like.

  In particular, when the assist piston 40 is displaced by the same amount as the displacement of the input rod 7 (when the relative displacement between the input rod 7 and the assist piston 40 is zero), the cross-sectional area of the input piston 16 is “AI”. When the sectional area of the assist piston 40 is “AA”, the boost ratio is uniquely determined as (AI + AA) / AI. That is, AI and AA are set based on the required boost ratio, and the assist piston 40 is controlled so that the displacement amount is equal to the displacement amount of the input piston 16, so that a constant boost ratio is always obtained. be able to. The displacement amount of the assist piston 40 can be calculated based on the output signal of the rotation angle detection sensor 205.

  Next, processing when executing the variable boost ratio function will be described. The boost ratio variable control process is a control process for displacing the assist piston 40 by an amount obtained by multiplying the displacement amount of the input piston 16 by a proportional gain (K1). K1 is preferably 1 from the viewpoint of controllability, but it is temporarily changed to a value exceeding 1 when a large braking force exceeding the driver's braking operation amount is required due to emergency braking or the like. May be. As a result, the reaction force acting on the input piston 16 is adjusted by the spring force of the neutral springs 19A and 19B acting on the relative displacement between the input piston 16 and the assist piston 40. The pressure can be increased compared to the normal time (when K1 = 1), and a larger braking force can be generated. Here, the emergency brake can be determined, for example, based on whether or not the time change rate of the signal of the operation amount detection device 8 exceeds a predetermined value.

  As described above, according to the boost ratio variable control process, the master pressure is increased or decreased according to the displacement amount of the input rod 7 according to the driver's brake request, so that the brake force as required by the driver is generated. be able to. Further, by setting K1 to a value less than 1, it is possible to apply to regenerative cooperative brake control in which the hydraulic brake is reduced by the regenerative braking force in a hybrid vehicle or an electric vehicle.

  Next, processing when the automatic brake function is performed will be described. The automatic brake control process is a process of moving the assist piston 40 forward or backward so as to adjust the operating pressure of the master cylinder 9 to the required hydraulic pressure of the automatic brake (hereinafter referred to as “automatic brake required hydraulic pressure”). As a control method of the assist piston 40, the displacement amount of the assist piston 40 that realizes the automatic brake required hydraulic pressure is extracted based on the relationship between the displacement amount of the assist piston 40 acquired in advance stored in the table and the master pressure. However, any method may be employed, such as a method of feeding back the master pressure detected by the master pressure sensor 57. The automatic brake request hydraulic pressure is received from an external unit. For example, it can be applied to brake control in vehicle following control, lane departure avoidance control, obstacle avoidance control, etc. That.

  Next, the configuration and operation of the wheel pressure control mechanism 6 will be described. The wheel pressure control mechanism 6 is configured to control the supply of brake fluid pressurized by the master cylinder 9 to the hydraulic brake devices 11 a to 11 d. The gate OUT valves 50 a and 50 b control the brake fluid pressurized by the master cylinder 9. Gate IN valves 51a and 51b for controlling the supply to the pumps 54a and 54b, IN valves 52a to 52d for controlling the supply of the brake fluid from the master cylinder 9 or the pumps 54a and 54b to the respective hydraulic brake devices 11a to 11d, and the liquid OUT valves 53a to 53d for pressure reduction control of the pressure brake devices 11a to 11d, pumps 54a and 54b for increasing the brake fluid pressure generated in the master cylinder 9, a motor 55 for driving the pumps 54a and 54b, and a master pressure for detecting the master pressure A sensor 56 is included. As the wheel pressure control mechanism 6, a hydraulic pressure control unit for antilock brake control, a hydraulic pressure control unit for vehicle behavior stabilization control, or the like can be used.

  The wheel pressure control mechanism 6 receives the supply of brake fluid from the primary fluid chamber 42, receives the supply of brake fluid from the first brake system that controls the brake force of the FL wheel and the RR wheel, and the secondary fluid chamber 43, and receives the FR. It consists of two systems of the 2nd brake system which controls the brake force of a wheel and RL wheel. By adopting such a configuration, even when one of the brake systems fails, the brake force for the two diagonal wheels can be secured by the normal other brake system, so that the behavior of the vehicle is kept stable. .

  The gate OUT valves 50a and 50b are provided between the master cylinder 9 and the IN valves 52a to 52d, and are opened when supplying the brake fluid pressurized by the master cylinder to the hydraulic brake devices 11a to 11d. . The gate IN valves 51a and 51b are provided between the master cylinder 9 and the pumps 54a and 54b. The brake fluid pressurized by the master cylinder is boosted by the pumps 54a and 54b and supplied to the hydraulic brake devices 11a to 11d. It is opened when you do.

  The IN valves 52a to 52d are provided upstream of the hydraulic brake devices 11a to 11d, and are opened when supplying brake fluid pressurized by the master cylinder 9 or the pumps 54a and 54b to the hydraulic brake devices 11a to 11d. Is done. The OUT valves 53a to 53d are provided downstream of the hydraulic brake devices 11a to 11d, and are opened when the wheel pressure is reduced. Note that each of the gate OUT valve, the gate IN valve, the IN valve, and the OUT valve is an electromagnetic type in which the valves are opened and closed by energizing a solenoid (not shown), and each of them is controlled by current control performed by the wheel pressure control device 5. The valve opening and closing amount can be adjusted independently.

  The gate OUT valves 50a and 50b and the IN valves 52a to 52d are normally open valves, and the gate IN valves 51a and 51b and the OUT valves 53a to 53d are normally closed valves. By adopting such a configuration, even when power supply to these valves is stopped at the time of failure, the gate IN valve and the OUT valve are closed, the gate OUT valve and the IN valve are opened, and the master cylinder 9 is pressurized. Since the brake fluid thus reached reaches all the hydraulic brake devices 11a to 11d, it is possible to generate a braking force as required by the driver.

  The pumps 54a and 54b increase the master pressure and hydraulic brake devices 11a to 11d when a pressure exceeding the operating pressure of the master cylinder 9 is necessary to perform vehicle behavior stabilization control, automatic brake control, and the like. To supply. As the pumps 54a and 54b, use of a plunger pump, a trochoid pump, a gear pump or the like is appropriate.

  The motor 55 operates with electric power supplied based on the control command of the wheel pressure control device 5 and drives the pumps 54a and 54b connected to the motor. As the motor, use of a DC motor, a DC brushless motor, an AC motor, or the like is appropriate.

  The master pressure sensor 56 is a pressure sensor that is provided downstream of the master pipe 102b on the secondary side and detects the master pressure. The number and installation positions of the master pressure sensors 56 can be arbitrarily determined in consideration of controllability, failsafe, and the like.

  The configuration and operation of the wheel pressure control mechanism 6 have been described above. When the master pressure control device 3 fails, the wheel pressure control device 6 uses the brake fluid pressure detected by the master pressure sensor 56 to The pumps 54a, 54b, etc. can be controlled so as to detect the amount of brake operation and generate wheel pressure according to the detected value.

  FIG. 2 shows an example of the circuit configuration of the master pressure control device 3 shown in FIG. A control circuit of the master pressure control device 3 is indicated by a solid line frame 201 in FIG. 2, and an electrical component and an electric circuit of the master pressure control mechanism 4 are indicated by a broken line frame 202. A solid line frame 5 indicates the wheel pressure control device 5. A broken line frame 208 indicates a sensor of the operation amount detection device 8. In the example shown in FIG. 2, the configuration includes two displacement sensors. However, the configuration may include at least one or more. That's fine. The sensor used here may be a pedaling force sensor or a master pressure sensor, or may be configured by combining at least two different sensors.

  First, in the control circuit surrounded by the solid line frame 201, the power supplied from the vehicle power supply E via the ECU power supply relay 214 is 5V power supply circuit 215 (hereinafter referred to as the first power supply circuit 215) and 5V power supply circuit 216 (hereinafter referred to as the first power supply circuit 216). 2 power supply circuit 215). The ECU power supply relay 214 is turned on by any one of a start signal and a start signal generated by CAN reception by the CAN communication I / F 218. The start signal is a door switch signal, a brake switch, an ignition switch signal. (Main switch) or the like can be used. When a plurality of switches are used, all are taken into the master pressure control device 3, and when any one of the plurality of signals is turned on, the start signal turns on the ECU power relay 214. The circuit is configured to operate on the side. In addition, when the vehicle power supply E fails, the power supplied from the auxiliary power supply 12 via the auxiliary power supply relay 236 can be supplied to the first power supply circuit 215 and the second power supply circuit 216. The stable power supply (VCC1) obtained by the first power supply circuit 215 is supplied to the central control circuit (CPU) 211. The stable power supply (VCC2) obtained by the second power supply circuit 216 is supplied to the monitoring control circuit 219.

  The fail safe relay circuit 213 can cut off the power supplied from the vehicle power source E to the three-phase motor drive circuit 222. The CPU 211 and the monitoring control circuit 219 supply power to the three-phase motor drive circuit 222. And the interruption can be controlled. Further, when the vehicle power supply E fails, power can be supplied from the auxiliary power supply 12 to the three-phase motor drive circuit 222 via the auxiliary power supply relay 235. Noise is removed from the power supplied from the outside through the filter circuit 212 and is supplied to the three-phase motor drive circuit 222.

  Next, a method of switching from the main power supply mode in which power is supplied from the vehicle power supply E to the auxiliary power supply mode in which power is supplied from the auxiliary power supply 12 when the vehicle power supply E fails will be described. The failure of the vehicle power source E here means a vehicle battery failure, a vehicle generator failure, and in the case of a hybrid vehicle or an electric vehicle, a motor generator failure, a high voltage battery failure, a DC / DC converter failure. This means that the vehicle power supply E cannot supply electric power to the electric equipment and the electronic control device mounted on the vehicle due to a failure of the low voltage battery or the like.

  First, the detection of the failure of the vehicle power supply E is performed by monitoring the voltage of the power supply line from the vehicle power supply E, and determining that the power supply has failed when the monitor voltage falls below a predetermined value. Thus, when the failure of the vehicle power supply E is detected, the auxiliary power supply relays 235 and 236 that are turned off in the normal state are turned on. As a result, power can be supplied from the auxiliary power supply 12. Further, it is desirable to turn off the ECU power supply relay 214 and the fail safe relay circuit 213 when the failure of the vehicle power supply E is detected and the auxiliary power supply relays 235 and 236 are turned on. If the cause of the failure of the vehicle power supply E is a short circuit failure to the GND of the vehicle body or the like somewhere in the vehicle power supply system, the power of the auxiliary power supply 12 is consumed until the fuse upstream from the short circuit point is blown. Because it will end up. Further, a circuit configuration may be adopted in which a diode is inserted either upstream or downstream of the ECU power supply relay 214 and the fail safe relay circuit 213 with the anode as the vehicle power supply E side.

  The CPU 211 receives vehicle information from the outside of the master pressure control device 3 via the CAN communication I / F circuit 218 and control signals such as an automatic brake request hydraulic pressure, and a master pressure control mechanism. Output from the rotation angle detection sensor 205, the motor temperature sensor 206, the displacement sensors 8a and 8b, and the master pressure sensor 57 arranged on the side 4 are the rotation angle detection sensor I / F circuit 225 and the motor temperature sensor I / F, respectively. The signals are input via a circuit 226, displacement sensor I / F circuits 227 and 228, and a master cylinder pressure sensor I / F circuit 229.

  The CPU 211 receives a control signal from an external device, a detection value of each sensor at the present time, etc., and outputs an appropriate signal to the three-phase motor drive circuit 222 based on these signals to control the master pressure control device 4. . The three-phase motor drive circuit 222 has an output terminal connected to the electric motor 20 in the master pressure control mechanism 4 and is controlled by the CPU 211 to convert DC power into AC power and drive the electric motor 20. In this case, each phase of the three-phase output of the three-phase motor drive circuit 222 is provided with a phase current monitor circuit 223 and a phase voltage monitor circuit 224, and these circuits 223 and 224 respectively provide a phase current and a phase voltage. With this information, the CPU 211 controls the three-phase motor drive circuit 222 so that the electric motor 20 in the master pressure control mechanism 4 operates appropriately. Then, when the monitor value in the phase voltage monitor circuit is out of the normal range, or when the control is not performed according to the control command, it is determined that a failure has occurred.

  In the control circuit 201 of the master pressure control device 3, for example, a storage circuit 230 that is a nonvolatile memory such as an EEPROM in which control information including failure diagnosis information and the like is stored, and a buffer storage that is a volatile memory such as a RAM A circuit 240 is provided, and signals are transmitted to and received from the CPU 211. The CPU 211 causes the buffer storage circuit 240 and the storage circuit 230 to appropriately store the detected failure diagnosis information and learning values used in the control of the master pressure control mechanism 4, such as control gains and offset values of various sensors. In addition, a monitoring control circuit 219 is provided in the control circuit 201 of the master pressure control device 3, and signals are transmitted to and received from the CPU 211. The monitoring control circuit 219 monitors a failure of the CPU 211, the VCC1 voltage, and the like. And when abnormality, such as CPU211 and VCC1 voltage, is detected, the fail safe relay circuit 213 is operated rapidly and the power supply to the three-phase motor drive circuit 222 is interrupted. The CPU 211 monitors the monitoring control circuit 219 and the VCC2 voltage.

  In this embodiment, auxiliary power supply relays 235 and 236 are mounted in the master pressure control device 3, and the power supply from the vehicle power supply E and the power supply from the auxiliary power supply 12 are switched inside the master pressure control device 3. However, the power supply control device on the vehicle side switches between the power supply from the vehicle power supply E and the power supply from the auxiliary power supply 12, and the power supply line to the master pressure control device 3 is from the vehicle power supply E in FIG. It can also be only.

  Next, the self-diagnosis function of the master pressure control device 3 will be described. The self-diagnosis function includes an operation amount detection device 8, a rotation angle detection sensor 205, an electric motor 20, master pressure sensors 56 and 57, a vehicle power supply E, an auxiliary power supply 12, sensors and actuators of the wheel pressure control mechanism 6, and wheel pressure. Monitors input signals from various in-vehicle sensors, actuators, controllers, power supplies, communication systems and other electronic components including the control device 5, detects abnormalities when the input signals are outside the normal range, Fault diagnosis information is appropriately stored in the buffer storage circuit 240 and the storage circuit 230, and predetermined processing is executed as necessary.

  As the failure diagnosis information, for example, a failure diagnosis code set for each failure part, a past failure information (when there is no failure but there was a failure in the past), a counter indicating the failure occurrence time Information (for example, counting up every time the ignition switch is turned on / off) and control state at the time of failure occurrence (capture information such as each sensor value and control command value) can be included.

  The master pressure control device 3 employs batch processing for failure diagnosis information writing processing, and executes failure diagnosis information writing processing in accordance with the execution of the main power supply mode and the auxiliary power supply mode. In any case, in the system operating state, when a failure is detected, the failure diagnosis information is temporarily written into the buffer storage circuit 240, which is a volatile memory, as needed. Then, according to the execution of the main power supply mode and the auxiliary power supply mode, the writing process is executed as follows.

(1) Normal termination processing by turning off the ignition switch (main switch) When the ignition switch is turned off by the driver during execution of the main power supply mode, transition to the normal termination processing is performed and the buffer storage circuit 240 is written. After executing the process of writing the failure diagnosis information in the storage circuit 230, the system is shut down.

(2) When the main power supply mode is changed from the main power supply mode to the auxiliary power supply mode due to the abnormality of the vehicle power supply E When the switching process to the auxiliary power supply mode is executed due to the abnormality of the vehicle power supply E during standby in the main power supply mode, Immediately after the supply of power from the power supply 12 is started, a write process at the time of auxiliary power transition for writing the failure diagnosis information written in the buffer memory circuit 240 into the memory circuit 230 is executed, and then the apparatus stands by in the auxiliary power mode. Then, the brake control function is maintained by the auxiliary power supply 12, and when an abnormality occurs during this time, failure diagnosis information is written in the buffer storage circuit 240. When the abnormality of the vehicle power supply E is resolved, the main power supply mode by the vehicle power supply E is restored.
As a result, since the capacity of the auxiliary power supply 12 is small, even if the power of the auxiliary power supply 12 is depleted before the system shuts down due to the ignition switch being turned off due to the operating state of the brake, the buffer is set before switching to the auxiliary power supply mode. Since the failure diagnosis information stored in the storage circuit 240 is already written and stored in the storage circuit 230 when switching to the auxiliary power supply mode, it can be read later.

(3) When the power supply of the auxiliary power supply 12 is reduced during execution of the auxiliary power supply mode During standby in the auxiliary power supply mode, the supply voltage of the auxiliary power supply 12 is monitored, and the supply voltage is less than a predetermined voltage (for example, an electric motor When the rated voltage of 20 is less than 9 volts when the rated voltage is 12 volts, the operation command for the electric motor 20 is terminated and written to the buffer memory circuit 240 because the power that can be supplied from the auxiliary power supply 12 is insufficient. The failure diagnosis information is written into the storage circuit 230, and the writing process when the auxiliary power supply is exhausted is executed. Thereafter, the brake control by the master pressure control device 3 is forcibly terminated when the power of the auxiliary power supply 12 is depleted. Here, the electric power necessary for executing the writing process when the auxiliary power supply is exhausted is smaller than the electric power necessary for the operation of the electric motor 20, so that it is necessary for the operation of the electric motor 20 by monitoring the decrease in the supply voltage. It is possible to detect that no power can be supplied.
As a result, failure diagnosis status information obtained during execution of the auxiliary power supply mode can be reliably written and stored in the storage circuit 230, and post-extraction can be performed.

An example of a control flow for executing the above-described failure diagnosis information writing process will be described with reference to FIG.
Referring to FIG. 3, in step S <b> 1, the vehicle stands by in the main power mode by the vehicle power source E, and in step S <b> 2, it is determined whether or not a transition to a normal control end process is made due to the driver's ignition switch being turned off. If it is determined that the transition to the normal control end process is made, in step S3, the fault diagnosis information and other control information written in the buffer storage circuit 240 are written in the storage circuit 230, and then in step S4, the master pressure control is performed. The power-off process of the control circuit 201 of the device 3 is executed.

  On the other hand, if it is determined in step S2 that it is not a transition to the normal control end process, the process proceeds to step S5. In step S5, it is determined whether or not switching to the auxiliary power supply 12 (transition to the auxiliary power supply mode) has been performed due to an abnormality in the vehicle power supply E. When the switching to the auxiliary power mode is being executed, the process proceeds to step S6, and when the switching is not being performed, the process returns to step S1.

  In step S6, the failure diagnosis information written in the buffer storage circuit 240 is written in the storage circuit 230, and the process proceeds to step S7. In step S7, it stands by in auxiliary power mode, and it progresses to step S8. In step S8, it is determined whether or not the abnormality of the vehicle power source E has been resolved. If it has not been resolved, the process proceeds to step S9. If it has been resolved, the process returns to the main power mode and returns to step S1. .

In step S <b> 9, the supply voltage of the auxiliary power supply 12 is monitored to determine whether or not electric power necessary for the operation of the electric motor 20 can be obtained. When the supply voltage is equal to or higher than the predetermined voltage (when the electric motor 20 can be operated), the process returns to step S7. When the supply voltage is lower than the predetermined voltage (when the electric motor 20 cannot be operated), the process proceeds to step S10. move on. In step S10, the operation of the electric motor 20 is terminated, and the process proceeds to step S11. In step S11, the failure diagnosis information written in the buffer storage circuit 240 is written in the storage circuit 230, and then, in step S12, standby is performed in the auxiliary power supply mode.
In this manner, the failure diagnosis information writing process is executed in accordance with the execution of the main power supply mode and the auxiliary power supply mode.

  In addition, in the said embodiment, although the structure which the input piston 16 is inserted in the master cylinder 9 is used, the input piston 16 does not necessarily need to be inserted in the master cylinder 9, and is a piston driven by an electric motor. May be inserted into the master cylinder. For example, the control of the above-described embodiment can be applied to a so-called by-wire type configuration in which the depression force of the brake pedal is not directly transmitted to the master cylinder.

  DESCRIPTION OF SYMBOLS 1 Brake control apparatus, 3 Master pressure control apparatus (control apparatus), 9 Master cylinder, 12 Auxiliary power supply, 20 Electric motor, 40 Assist piston (piston), 100 Brake pedal, E Vehicle power supply (main power supply), 230 Memory circuit ( Nonvolatile memory), 240 Buffer storage circuit (volatile memory)

Claims (1)

A master cylinder that generates brake fluid pressure by propulsion of the piston;
An electric motor for driving the piston;
A control device for controlling the operation of the electric motor according to the operation of the brake pedal;
A main power source and an auxiliary power source for supplying electric power to the electric motor and the control device;
The control device normally executes a main power mode in which power is supplied to the control device and the electric motor by a main power source, and when the abnormality on the main power source side is detected, the control device and the electric motor power are detected by the auxiliary power source. In the brake control device that executes the auxiliary power mode for supplying power to the motor,
The controller is
When a failure of the brake control device is detected, the failure diagnosis information is written in the volatile memory, and when executing a predetermined control termination process, the failure diagnosis information written in the volatile memory is written in the nonvolatile memory. Trouble diagnosis function
Further, when a transition is made from the main power supply mode to the auxiliary power supply mode, immediately after the power supply by the auxiliary power supply is started, the failure diagnosis information written in the volatile memory is written in the nonvolatile memory, and the auxiliary power supply mode During the execution, when the power that can be supplied from the auxiliary power source falls below a predetermined power , the power supply to the electric motor is terminated, and the failure diagnosis information written in the volatile memory is again displayed in the nonvolatile memory. Brake control device characterized by writing in

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