JP2005343248A - Parking assist brake controlling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parking assist brake controlling device equipped with the fail-safe function capable of managing well with occurrence of a brake failure which is sensed when the parking assist brake control is to be executed. <P>SOLUTION: When a brake failure is sensed by a brake control ECU during the parking assist brake control, the control is ended, and a control signal to issue an alarm to the driver is emitted, while a second drive signal is emitted to a motor-driven parking brake, and the vehicle is stopped forcedly by generating a braking force. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a parking assist brake control device that applies a braking force to wheels of a vehicle when assisting parking in the vehicle.

In recent years, a parking assistance control device has been developed that performs parking assistance control that facilitates parking by assisting parking in a vehicle. For example, when the driver presses the parking assist switch provided in the passenger compartment, the vehicle automatically moves to the parking space, and the driver parks the car without doing anything. There are those that give instructions for operating the steering wheel, such as “Please turn the steering wheel to the left” when the vehicle moves, and those that show the movement trajectory of the parked vehicle (for example, patents) Reference 1). At this time, when the vehicle is automatically moved, a parking assist brake control is performed to set the vehicle to an appropriate predetermined speed (for example, a constant speed) while appropriately applying a braking force to the wheels by an automatic pressurization system that is an existing technology. There is something to do. Such a device is called a parking assist brake device.
JP 2000-280823 A

  In the parking assist brake control device as described above, a brake failure (brake failure) of the automatic pressurization system may occur. However, the conventional parking assist brake control device does not take any measures against such a brake failure. Therefore, when a brake failure occurs, the braking force cannot be automatically generated during the parking assist control, and there is a possibility that the vehicle cannot be appropriately moved at a predetermined speed. In such a case, a countermeasure is taken to give a warning to the driver and prompt a brake operation. For this reason, it is desirable to provide a fail-safe function that can cope with a brake failure occurring in the parking assist brake control device.

  In the parking assist brake control device, when the initial check is performed after the ignition switch is turned on, the electromagnetic valve provided in the automatic pressurization system for applying the braking force in the parking assist brake control device is idled. In some cases, a hardware abnormality check is performed. However, even in such a case, in the check immediately before the parking assist brake control, only an electrical abnormality check of the automatic pressurization system is performed, and a hardware abnormality check is not performed. Therefore, a hardware abnormality may occur during parking assist brake control.

  In view of the above points, the present invention provides a parking assist brake control device having a fail-safe function capable of responding to a brake failure when a brake failure occurs in the automatic pressurization system when executing the parking assist brake control. The purpose is to provide.

  In order to achieve the above object, according to the first aspect of the present invention, the abnormality detecting means (103) controls the speed of the vehicle during the parking assist brake control. When it is detected that an abnormality has occurred in the first brake means (2) for applying a braking force to each wheel (4FL, 4FR, 4RL, 4RR) provided, the vehicle braking control means (115) The vehicle is caused to travel or stop at a predetermined speed by outputting an instruction signal to the second brake means (3) different from the brake means and generating a braking force.

  Thus, when a brake failure occurs in the first brake means during the parking assist brake control, the second brake means causes the vehicle to form a predetermined speed (for example, a constant speed) or automatically stops the vehicle. Thus, when executing the parking assist brake control, when a brake failure is detected, a parking assist brake control device having a fail-safe function that can cope with the brake failure can be provided.

  In the second aspect of the invention, the target deceleration detecting means (109) obtains the target deceleration from the data indicating the vehicle speed, controls the braking force applied to the wheel by the vehicle braking control means, and detects the target deceleration. An instruction signal is outputted from the vehicle braking control means so that the target deceleration obtained by the means can be obtained.

  Thus, if the target deceleration according to the vehicle speed is set and the vehicle is stopped, the stop of the vehicle can be prevented from sudden braking. It is to be noted that, as shown in claim 3, the instruction signal may be output from the vehicle braking control means so that the deceleration increasing gradient obtained by the deceleration increasing gradient detecting means is obtained. Similar effects can be obtained.

  According to a fourth aspect of the present invention, an instruction signal is output to the second brake means to generate a braking force according to a place where the abnormality of the first brake means has occurred, or an instruction signal is sent to the second brake means. It is also possible to change whether the braking force is generated by the first brake means without outputting. Thereby, it becomes possible to continue parking assistance brake control according to the place where abnormality in the 1st brake means occurred.

  For example, as shown in claim 5, when the first brake means is configured to add a braking force by dividing the wheels provided in the vehicle into two systems, the abnormality of the first brake means If the generated place is only one of the two systems, the braking force can be generated by the first brake means and the parking assist brake control can be continued.

  Further, as shown in claim 6, when an abnormality occurs in both systems of the first brake means, an instruction signal is output to the second brake means, and a braking force is generated by the second brake means. May be.

  In addition, as a 2nd brake means in the vehicle braking control means here, as shown in Claim 7, an electric parking brake can be mentioned.

  Moreover, in the said Claim 1 thru | or 7, although this invention was shown as a form of a parking assistance brake control apparatus, this invention is not necessarily applied only to such a form. For example, as shown in claim 8, the present invention can be grasped as a form of a parking assist brake control program, and the present invention can be grasped as other forms such as a parking assist brake control method. .

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A parking assistance brake device mounted on a vehicle to which an embodiment of the present invention is applied will be described with reference to the drawings.

  The parking assist brake device of the present embodiment relates to a parking assist brake device that operates in a constant speed mode, a stop mode, and the like, similarly to the device disclosed in Japanese Patent Application Laid-Open No. 2004-50925.

  FIG. 1 is a diagram illustrating an overall configuration of a parking assist brake device according to the present embodiment. In the figure, the front right wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle VL are represented by FR, FL, RR, and RL as components corresponding thereto.

  The parking assist brake device according to the present embodiment includes a brake control ECU 1, a hydraulic brake device 2, an electric parking brake (hereinafter referred to as PKB) 3, and wheel cylinders (hereinafter referred to as W 41FR, 41RL, 41FL, wheel speed sensors 5FR, 5RL, 5FL, 5RR, in-vehicle LAN bus 6, engine ECU 7, peripheral monitoring control ECU 8, warning display / alarm device 9, various sensors 50, and braking request output The unit 80 is configured to be provided.

  Among these components, the brake control ECU 1, engine control ECU 7, peripheral monitoring control ECU 8, warning display / alarm device 9, sensors 50, and braking request output unit 80 are each connected to the in-vehicle LAN bus 6 and in-vehicle LAN Signals can be transmitted and received with each other via the bus 6.

  The brake control ECU 1 constitutes a vehicle braking control means, and is constituted by a computer. The brake control ECU 1 is constituted by a computer, a braking request from the peripheral monitoring control ECU 8 and the braking request output means 80 via the in-vehicle LAN bus 6, and each wheel speed sensor 5a. ˜5d and sensor signals from sensors 50 are input, and a drive signal for controlling hydraulic brake device 2 and PKB 3 described later and a control signal to engine control ECU 7 are output.

  The hydraulic brake device 2 constitutes the first brake means in the present invention, and the PKB 3 constitutes the second brake means in the present invention.

  FIG. 2 is a diagram showing a specific piping configuration of the hydraulic brake device 2 serving as the first brake means. The hydraulic brake device 2 will be described with reference to this figure.

  A master cylinder (hereinafter referred to as “M / C”) 10 is configured such that when a brake pedal (not shown) is depressed by a driver, the M corresponding to the depression force of the brake pedal detected by a brake operation amount sensor 53 (described later) included in the sensors 50. / C pressure is generated. The first piping system 11 and the second piping system 21 are connected to the M / C 10, and the W / C 41 FR, 41 RL, 41 FL, and 41 RR are diagonally connected to the piping systems 11 and 21. .

  The brake hydraulic pressure generated by the M / C 10 is transmitted to the W / C 41FR, 41RL and 41FL, 41RR provided in each wheel via the first piping system 11 and the second piping system 21, respectively. A braking force is generated.

  Hereinafter, the first piping system 11, particularly, the piping system related to the right front wheel 4FR will be mainly described, but the same applies to other wheels and the second piping system.

  The first piping system 11 is provided with pressure increase control valves 14a and 14b for adjusting the pressure increase and holding of the W / C 41FR and 41RL during ABS control for the right front wheel 4FR and the left rear wheel 4RL, respectively. Yes. Check valves 141a and 141b are provided in parallel to the pressure increase control valves 14a and 14b, respectively, and the liquid flow is transferred to the M / C 10 side when the W / C pressure becomes excessive when the pressure increase control valves 14a and 14b are shut off. It is supposed to escape.

  Pressure reducing control valves 15a and 15b for adjusting the pressure reducing and holding of the W / C 41FR and 41RL in the ABS control are provided in the pressure reducing pipe 12 extending from between the pressure increasing control valves 14a and 14b and the W / C 41FR and 41RL. . The pressure reducing line 12 is connected to a reservoir 16.

  The brake fluid stored in the reservoir 16 is pumped up by a pump 17 driven by a motor 20, and then between the pressure increase control valves 14 a and 14 b and a master cut valve (hereinafter referred to as SM valve) 18 described later. Yes. A check valve 171 is provided at the discharge port of the pump 17 so that high brake fluid pressure is not applied to the discharge port of the pump 17.

  An SM valve 18 is disposed between the M / C 10 and the pressure increase control valves 14a and 14b. The SM valve 18 is a two-position valve that is in a communicating state when not energized, and is in a shut-off state by a check valve in the illustrated direction when energized. In the shut-off state, the SM valve 18 is released when the pressure on the W / C 41 FR, 41 RL side becomes higher than the pressure on the cracking pressure M / C 10 side by the check valve spring, thereby releasing the pressure. ing. The SM valve 18 is provided with a check valve 181 in parallel so that only flow from the M / C 10 side to the W / C 41 FR and 41 RL side is allowed.

  The M / C 10 and the SM valve 18 are connected to the reservoir 16 by a suction line 13.

  A hydraulic pressure sensor 30 is provided between the M / C 10 of the first piping system 11 and the SM valve 18 so that the brake fluid pressure generated by the M / C 10 can be detected. The brake fluid pressure detected by the hydraulic sensor 30 is a pressure generated in a secondary chamber (not shown) of the M / C 10, but the same pressure is also generated in the primary chamber to which the second piping system is connected. The sensor 30 can substantially detect the M / C pressure.

  Also, hydraulic pressure sensors 19a and 19b are provided between the pressure increase control valves 14a and 14b and the W / C 41FR and 41RL so that the respective W / C pressures can be detected.

  The output signals of the hydraulic sensor 30 and the hydraulic sensors 19a and 19b are input to the brake control ECU 1.

  The pressure-increasing control valves 14a and 14b and the pressure-reducing control valves 15a and 15b are two-position valves. When the brake pedal is not operated and during normal braking, the valve body position shown in FIG. The control valves 14a and 14b are in communication, and the pressure reduction control valves 15a and 15b are in a cut-off (cut) state. Further, the SM valve 18 is also in the illustrated valve body position, that is, in a communicating state during normal non-energization.

  Each of these control valves is driven by an operation signal from the brake control ECU 1. The motor 20 that drives the pumps 17 and 27 is also driven by an operation signal from the brake control ECU 1.

  Each operation signal for the hydraulic brake device 2 generally corresponds to a first drive signal. Further, when the hydraulic brake device 2 is stopped (or prohibited), the first drive signal is set to 0 (non-operating state), specifically, the pressure increase control valves 14a, 14b, 24a, 24b, pressure reduction control. This means that the valves 15a, 15b, 25a, 25b and the SM valves 18, 28 are all de-energized and the drive current of the motor 20 is zero. Therefore, when the first drive signal is released, the braking force of the first brake means indicated by the hydraulic brake device 2 is also released (braking force = 0).

  In the hydraulic brake device 2 as the first brake means configured as described above, an abnormality check is performed to detect whether or not a brake failure has occurred. This abnormality check includes a hardware check and an electric check.

  In the hardware check, the pressure increase control valves 14a, 14b, 24a, 24b, the pressure reduction control valves 15a, 15b, 25a, 25b and the SM valves 18, 28 are operated, and the motor 20 is driven to drive the pump 17 , 27 is activated. At this time, if each of these hardware components operates normally, it is assumed that there is no abnormality, and if it does not operate, an abnormality is detected. Such a hardware abnormality check is performed, for example, at an initial check performed immediately after the ignition switch is turned on or when parking assist brake control is executed.

  The electrical abnormality check is performed by detecting whether or not the brake control ECU 1 that generates a control signal for operating each hardware component normally operates when the hardware abnormality check is performed. That is, if a control signal for operating each hardware configuration is normally output, it is assumed that there is no abnormality, and if it is not normally output, an abnormality is detected.

  If an abnormality is detected during the abnormality check, an abnormality detection flag in a memory (not shown) provided in the brake control ECU 1 is set so that it is possible to confirm that a brake failure has occurred.

  Subsequently, a basic control method of the hydraulic brake device 2 will be described.

  In a normal brake operation when the driver depresses the brake pedal, all the control valves (SM valve 18, pressure increase control valve 14a, pressure reduction control valve 15a) are in a non-energized (OFF) state. For this reason, the M / C pressure acts on the W / C 41FR and 41RL as they are, so that W / C pressure = M / C pressure.

  During the ABS control, the operation differs between a process of reducing the W / C pressure in order to avoid tire lock and a process of increasing the W / C pressure in order to recover the braking force. The SM valve 18 is normally OFF (communication state) during the ABS control, and the pump 17 is driven to suck the brake fluid from the reservoir 16.

  First, in the depressurization process of the ABS control, the pressure increase control valve 14a is set in an energized state (ON), that is, a cut (cut) state, and the pressure decrease control valve 15a is controlled with an ON / OFF duty ratio. As a result, the communication / cut switching is repeated, and the brake fluid flows from the W / C 41 FR to the reservoir 16 with a predetermined change gradient, thereby reducing the W / C pressure.

  In the pressure increasing process of the ABS control, the pressure reducing control valve 15a is set in a non-energized state (OFF), that is, in a cut state, and the pressure increasing control valve 14a is controlled in an OFF / ON duty ratio. As a result, the communication / cut switching is repeated, the brake fluid is supplied from the M / C 10 to the W / C 41 FR, and the W / C pressure is increased.

  Next, regardless of whether there is parking assist brake control, that is, whether or not the brake pedal is depressed, the brake control ECU 1 controls the hydraulic brake device 2 based on the brake request signal from the surrounding monitoring control ECU 8 or the brake request output means 80. The pressure increasing process and the pressure reducing process during the braking operation instructed will be described.

  In the pressure increasing process of the parking assist brake control, the SM valve 18 is turned on (cut state), and the pressure reducing control valve 15a is turned off (cut state). Further, in a state where the pump 17 is driven and the brake fluid is sucked from the reservoir 16 to generate the discharge pressure, the pressure increase control valve 14a is turned OFF / ON while comparing with the detection value of the hydraulic sensor 19a. By the ratio control, the W / C pressure is increased at a predetermined change gradient or to a set target pressure. At this time, brake fluid is replenished to the suction port of the pump 17 from the M / C 10 through the suction line 13 and the reservoir 16 as necessary.

  In the depressurization process of the parking assist brake control, the SM valve 18 is turned on (cut state), the pressure increase control valve 14a is turned on (cut state), and the pump 17 is driven to suck brake fluid from the reservoir 16. In a state where the discharge pressure is generated, the pressure reduction control valve 15a is adjusted to a predetermined gradient by ON / OFF duty ratio control or to a set target pressure while comparing with the detected value of the hydraulic sensor 19a. Brake fluid is sucked from W / C41FR to reduce the W / C pressure. At this time, since both the pressure increase control valve 14a and the SM valve 18 are in the cut state, the discharge pressure of the pump 17 increases, but is released when the pressure exceeds the cracking force of the check valve spring of the SM valve 18. Pressure drops.

  Next, PKB3 which is a 2nd brake means is demonstrated.

  The PKB 3 is connected to the brake calipers of the brake wires 31R and 31L, the rear wheels 4RL and 4RR. The PKB 31 is driven by a brake caliper of the left and right rear wheels 4RR, 4RL via a brake wire 31R, 31L by an actuator (not shown) operated by a second drive signal from the brake control ECU 1 and a gear mechanism. A braking force, that is, a second braking force is generated. The motor of PKB3 is driven in a duty manner based on the second drive signal to be rotated forward or backward. As a result, the magnitude of the second braking force is controlled.

  At this time, a braking force corresponding to the duty ratio is generated. When the target braking force is reached, the motor of the PKB 3 is locked, and when the motor lock is detected, the driving current of the motor is cut off, that is, the second driving signal is released. Thus, the PKB 3 enters a control stop (control prohibited) state. Since the gear mechanism does not move in the control stop state of PKB3, the second braking force is maintained and the lock state is established.

  This PKB3 is not controlled by the second drive signal from the brake control ECU 1 during parking assist brake control, but also when the driver operates a parking brake switch (not shown) on / off based on the operation signal. The ECU 1 is driven by outputting a second drive signal of the PKB 3.

  As shown in FIG. 2, the wheel speeds 5FL to 5RR sensors are provided in the respective wheels so that the rotational speeds of the respective wheels can be detected, and the respective output signals are directly input to the brake control ECU 1. Yes. For the wheel speed sensors 5FR, 5FL, 5RR, 5RL, for example, a semiconductor speed sensor using a Hall element is used, and by obtaining a reliable wheel rotation pulse even at a low speed, an accurate vehicle speed can be detected even at a parking speed. It has become.

  The engine control ECU 7 adjusts the fuel injection amount in accordance with the running state based on the accelerator opening signal that is the accelerator operation amount from the accelerator operation amount sensor 52, the engine speed, the water temperature, the oxygen concentration in the exhaust, and the like. The engine output is controlled by giving a command value to 70. As a result, the driving forces of the left and right front wheels 4FR and 4FL that are rotationally driven via the automatic transmission (AT) 71 and the axles 72R and 72L are adjusted.

  The AT 71 is a known device that incorporates a torque converter that transmits the rotation of the engine 70 to the axles 72R and 72L, and the transmission is controlled by a control device (not shown). In the present embodiment, parking assist brake control is performed by actively using a state in which the vehicle travels at a low speed due to a creep phenomenon (hereinafter referred to as creep travel), and the control of AT 71 is not particularly relevant. Description of the control device will be omitted.

  That is, in the present embodiment, the engine control ECU 7 increases the engine output from the idle state or decreases the output to the idle state by the engine output adjustment signal from the brake control ECU 1, The vehicle VL is caused to travel in the constant speed mode by using the braking force control by the control ECU 1 together.

  The surrounding monitoring control ECU 8 corresponds to surrounding monitoring means, and is based on a distance x to an obstacle measured by an obstacle sensor 54 (described later) included in the sensors 50 and a distance to a position where the vehicle VL should be stopped. A braking distance L is calculated. Then, the periphery monitoring control ECU 8 outputs the obtained braking distance L to the brake control ECU 1 as a braking request value.

  The warning display / alarm device 9 is provided with a warning indicator such as a lamp and a display and an alarm device such as a buzzer and a speaker. A warning sound is sent to the driver.

  The sensors 50 include a steering amount sensor 51, an accelerator operation amount sensor 52, a brake operation amount sensor 53, and an obstacle sensor 54.

  The steering amount sensor 51 detects the steering amount of the steering wheel, and the accelerator operation amount sensor 52 detects the operation amount of the accelerator pedal. The brake operation amount sensor 53 detects the operation amount of the brake pedal.

  The obstacle sensor 54 is for detecting an obstacle around the vehicle VL, and is a distance x to an obstacle existing in the front and rear of the vehicle by corner sonar provided in, for example, a bumper at the front and rear of the vehicle. Is sent to the brake control ECU 1 and other braking request output means via the in-vehicle LAN bus 6 together with the differential signal. The differential signal of the distance x corresponds to a relative speed with an obstacle such as a traveling vehicle ahead or behind.

  The braking request output unit 80 corresponds to braking request output means, and includes a traffic jam tracking ECU 81, an inter-vehicle distance control ECU 82, and a dozing prevention ECU 83.

  The traffic jam tracking ECU 81 detects the braking and stopping states of the forward vehicle when there is a traffic jam, and the target deceleration for stopping or maintaining the inter-vehicle distance at a predetermined inter-vehicle distance without colliding with the forward vehicle from the vehicle speed of the host vehicle VL. (For example, “0.23 G (G: deceleration of gravity acceleration)”) is calculated. Then, the traffic jam tracking ECU 82 outputs the calculation result as an ECU request value to the brake control ECU 1 via the in-vehicle LAN bus 6.

  Based on this, the brake control ECU 1 converts the deceleration shown as the ECU required value into the braking pressure (braking hydraulic pressure) assuming that the deceleration 1G corresponds to the braking pressure of 10 MPa (Pa: pressure unit, Pascal), for example. , To come to evaluate its size.

  The inter-vehicle control ECU 82 detects the distance and relative speed between the obstacles such as the front and rear vehicles and the own vehicle VL, and sets the inter-vehicle distance to the obstacle to a predetermined value set in advance or changed by the driver. The drive control by the engine control ECU 7 and the brake control by the brake control ECU 1 are performed so as to maintain the control.

  Further, a target braking distance (for example, “stop at 28 m”) is output to the brake control ECU 1 as an ECU request value. In addition, when the distance between the front and rear obstacles is abruptly reduced, there is a possibility that a pedestrian or the like suddenly jumps out in the vehicle traveling direction. Therefore, a braking request that enables sudden braking is issued. The distance from the front and rear obstacles is detected by the obstacle sensor 54.

  Based on this, the brake control ECU 1 obtains the target deceleration from the current vehicle speed and the target braking distance, or sets the maximum deceleration at the time of sudden braking, and converts this to the braking pressure as described above, It has come to evaluate.

  The dozing prevention ECU 83 detects the driving operation state or the physiological state of the driver, determines the driver's dozing state, and performs an alarm such as a buzzer or intermittent momentary braking to prompt the driver to wake up. However, in this embodiment, the time change value of the target brake hydraulic pressure for awakening is given to the brake control ECU 1 as the ECU request value. The time change of the braking force can be, for example, a triangular wave shape.

  As described above, the parking assist brake device of the present embodiment is configured. In the parking assist brake device configured as described above, when a parking assist brake control start switch (not shown) is turned on and a parking assist mode in which the above-described parking assist control is executed is set, the parking assist brake control is executed. It has come to be. This parking assistance brake control is executed during parking assistance control. Specifically, the brake control ECU 1, the engine control ECU 7, and the peripheral monitoring ECU 8 detect detection signals from the wheel speed sensors 5FL to 5RR, the W / C pressure sensors 19a, 19b, 29a, 29b, and the sensors 50, and further, braking. Various controls such as parking assist brake control and fail-safe control are executed based on the target deceleration output as the ECU request value from the request output unit 80.

  When the parking assist brake control is executed, when the distance x between the vehicle VL and the obstacle is relatively long, the target speed (creep speed) corresponding to the brake operation amount and the road gradient is obtained by the operation in the constant speed mode. ) Is adjusted so that the vehicle VL creeps, and when the distance x to the obstacle is shortened, the operation is switched to the operation in the stop mode, and the braking force is generated so that the braking distance determined according to the vehicle speed is obtained. Adjustment is made so that the vehicle VL decelerates.

  The details of such parking assist brake control are the same as those disclosed in Japanese Patent Application Laid-Open No. 2004-50925 and the like, and are therefore omitted here.

  Next, the fail safe control executed during the parking assist brake control will be described.

  In this fail-safe control process, if a brake failure occurs during the parking assist brake control, the brake force may not be generated by the hydraulic brake device 2; Is detected, the braking force is generated by the PKB 3.

  FIG. 3 shows a flowchart of the fail-safe control process. The fail-safe control process shown in this flowchart is executed every predetermined control period when the brake control ECU 1 turns on a parking assist brake control start switch (not shown) in the vehicle.

  First, in step 101, it is determined whether or not parking assist brake control is being performed. For example, when parking assist brake control is executed, a flag of a memory (not shown) provided in the brake control ECU 1 is set, and this determination is made by checking whether the flag is set or reset. It can be performed.

  If an affirmative determination is made in this step, it is determined that the parking assist brake control is being performed, and the routine proceeds to step 103.

  In step 103, it is determined whether or not a brake failure has been detected. This determination is made based on whether or not an abnormality detection flag is set in a memory (not shown) provided in the brake control ECU 1 by the abnormality check performed when the parking assist brake control is executed as described above. If the abnormality detection flag is not set, there is no problem. For this reason, when a negative determination is made in this step, the processing is ended as it is. If an affirmative determination is made in this step, the process proceeds to step 105.

  In step 105, since there is a possibility that a brake failure has occurred and no braking force can be generated by the hydraulic brake device 2, a process for terminating the parking assist brake control is executed. As a result, the first drive signal issued to generate the braking force by the hydraulic brake device 2 is not output, and the parking assist brake control is terminated.

  Then, it progresses to step 107 and a warning process is performed. In this process, a warning signal and a control signal indicating that fail-safe control has been executed are output to the warning display / alarm device 9 in order to issue a warning by a lamp or display. As a result, the warning display / alarm device 9 is lit on the lamp, displayed on the display, and an alarm with a warning sound through a buzzer or speaker is performed, and the driver is informed that the brake has failed and the fail-safe control is executed. Is done.

  Next, in step 109, the target deceleration and deceleration increase gradient are selected based on the current vehicle speed. As the current vehicle speed, for example, a vehicle speed obtained during parking assist brake control based on signals from the wheel speed sensors 5FL to 5RR, or a vehicle speed already obtained by another ECU is used. The deceleration increase gradient selection is performed using a deceleration increase gradient map corresponding to the vehicle speed provided in the brake control ECU 1 in advance.

  Subsequently, the routine proceeds to step 111, where the control brake force for obtaining the selected deceleration increasing gradient is calculated. Note that the conversion of braking pressure to deceleration is the same as described above.

  Subsequently, the routine proceeds to step 113, where it is determined whether or not the control braking force is greater than the braking force requested by the driver (hereinafter referred to as driver-requested braking force). The driver-required braking force here means a braking force generated in response to the driver depressing the brake pedal. If the control braking force is greater than the driver required braking force, it means that a braking force greater than the driver's request is required, and the process proceeds to step 115 to generate the control braking force. On the other hand, if the braking force required by the driver is greater than the control braking force, the braking force required by the driver is greater than the braking force required by fail-safe control. The driver's requested braking force is prioritized. In this case, the process skips step 115 and ends as it is.

  In step 115, a forced braking process for generating a control braking force is executed. Specifically, a second drive signal that instructs to generate a braking pressure corresponding to the control braking force is output. Thereby, the magnitude | size of the 2nd braking force which PKB3 generates is adjusted, and a control braking force is generated. When this forced braking process is executed, a forced braking flag (not shown) provided in the brake control ECU 1 is set to indicate that this process has been executed.

  On the other hand, if a negative determination is made in step 101, it is determined that the parking assist brake control is not performed or the parking assist brake control is forcibly terminated, and the process proceeds to step 117.

  In step 117, it is determined whether or not the forced braking process has been executed. This determination is made based on whether or not the above-described forced braking flag is set. If the forced braking flag is set, the process proceeds to step 119. If the forced braking flag is reset, the process ends. For example, the vehicle VL is stopped by the braking force generated based on the driver's brake pedal operation even when a brake failure occurs during normal driving where the parking assist brake control is not executed or during the parking assist brake control. If it does, a negative determination will be made at this step.

  In step 119, it is determined whether a release operation has been performed after the forced braking process has been executed. Here, the release operation means that the vehicle VL is stopped for a certain period of time or an accelerator operation is performed. The presence / absence of such a release operation is determined based on detection signals from the wheel speed sensors 5FL to 5RR or based on detection signals from the accelerator operation amount sensor 52.

  If an affirmative determination is made in this step, the forced braking flag is reset, and then the process proceeds to step 121 where a forced braking release process is executed, and the second drive signal is released to release the braking pressure generated in PKB3. Is done. If a negative determination is made in this step, the process is terminated as it is. In this case, the braking pressure generated in the PKB 3 set in the forced braking process is maintained.

  As described above, according to the parking assist brake device of this embodiment, the vehicle VL is automatically stopped when a brake failure occurs during the parking assist brake control. Thus, when executing the parking assist brake control, when a brake failure is detected, a parking assist brake control device having a fail-safe function that can cope with the brake failure can be provided.

  Further, in the fail-safe control of the present embodiment, a deceleration increase gradient corresponding to the vehicle speed is selected, and the vehicle VL is decelerated and stopped so that the selected deceleration increase gradient is obtained as a target deceleration. I have to. For this reason, it is possible to prevent the vehicle VL from stopping suddenly.

  However, if the driver-requested braking force is greater than the control braking force for obtaining the deceleration increase gradient selected here, the driver's braking intention can be increased by ensuring that the driver-requested braking force is obtained. You can respect it.

  Note that the steps shown in FIG. 3 correspond to means for executing various processes.

(Second Embodiment)
A second embodiment of the present invention will be described. The present embodiment is different from the first embodiment in the content of fail-safe control processing executed by the brake control ECU 1, and the configuration of the parking assist brake control device is the same as that of the first embodiment. Therefore, only different parts will be described.

  In the first embodiment, when the brake failure occurs, the vehicle VL is forcibly stopped using the PKB 3, but in this embodiment, parking assistance is performed according to the brake failure mode. Whether to continue the brake control or to forcibly stop the vehicle VL is determined, and the control mode is changed.

  FIG. 4 shows a flowchart of the fail safe control process executed by the brake control ECU 1 in the parking assist brake control device of the present embodiment.

  In steps 101 and 103 shown in this figure, processing similar to that in steps 101 and 103 in FIG. 3 shown in the first embodiment is executed. When a brake failure is detected in step 103, the process proceeds to step 201, and a control mode corresponding to the content of the brake failure is determined. In other words, in step 201, whether the brake failure is an abnormality detected in only one of the two systems of piping provided in the hydraulic brake device 2, or an abnormality detected in both systems. Is determined.

  For example, when an abnormality is detected during the abnormality check described in the first embodiment, this determination is performed by setting an abnormality detection flag and storing the object in which the abnormality is detected. Is performed by checking which one of the two systems of piping configurations belongs.

  As a result, if the abnormality is detected in any one of the two systems, the process proceeds to step 203 where warning processing for the driver is performed. In this process, a brake failure has occurred in one of the two systems of pipes provided in the hydraulic brake device 2 in the warning display / alarm device 9 in order to give a warning sound and warning by a lamp or display. A control signal indicating is output. As a result, the warning display / alarm device 9 is lit with a lamp, displayed on the display, or warned with a warning sound through a buzzer or speaker, and notifies the driver that a brake failure has occurred.

  On the other hand, if an abnormality is detected in both systems in step 201, the processing from step 105 is executed as in the first embodiment.

  Moreover, also in the case where the parking assist brake control is not being performed in step 101, the processing after step 111 is executed in the first embodiment.

  As described above, in the present embodiment, when an abnormality is detected only in one of the two systems of the piping configuration provided in the hydraulic brake device 2, while giving a warning to that effect, Parking assistance brake control is continued. For this reason, it is possible to continuously execute the parking assist brake control while notifying the driver that a brake failure has occurred.

  Note that, during the parking assist brake control, the vehicle VL is creeping at a low speed, so that even if only one of the hydraulic brake devices 2 can generate the braking pressure, it is sufficient. The vehicle speed can be reduced, and there is no problem even if the control as in this embodiment is performed.

(Third embodiment)
A third embodiment of the present invention will be described. The present embodiment is different from the first embodiment in the content of fail-safe control processing executed by the brake control ECU 1, and the configuration of the parking assist brake control device is the same as that of the first embodiment. Therefore, only different parts will be described.

  In the first embodiment, when the brake failure occurs, the vehicle VL is forcibly stopped using the PKB 3. In the present embodiment, the vehicle speed in the vehicle VL is adjusted using the PKB 3. Continue parking assist brake control.

  FIG. 5 shows a flowchart of the fail-safe control process executed by the brake control ECU 1 in the parking assist brake control device of the present embodiment.

  In steps 101 and 103 shown in this figure, processing similar to that in steps 101 and 103 in FIG. 3 shown in the first embodiment is executed.

  If it is determined in step 103 that a brake failure has occurred, the process proceeds to step 107 without performing the process shown in step 105 of FIG. 3 in the first embodiment, and a warning process is performed. .

  Thereafter, the process proceeds to step 301 where a second drive signal corresponding to the braking force applied to the PKB 3 necessary for generating the target deceleration determined in the parking assist brake control is output so that creep travel can be performed. As a result, braking force is generated on the wheels 4RL and 4RR by the PKB 3, and the creep running determined by the parking assist brake control is realized.

  As described above, in the present embodiment, when the brake failure occurs in the hydraulic brake device 2, the parking assist brake control can be continued by generating the braking force by the PKB3. As described above, when the first brake means and the second brake means exist as the braking force applying means, the second brake means is used even if the first brake means used for the parking assist brake control at the time of brake failure occurs. Thus, the parking assist brake control can be continued.

(Other embodiments)
In the above-described embodiment, the first brake means is the hydraulic brake 2 and the second brake means is the PKB 3. However, these structures are not necessarily required as long as the braking force can be automatically generated. For example, you may comprise a 1st, 2nd brake means with an electric brake. Furthermore, when a configuration such as a regenerative brake is included, an automatic braking force may be generated in cooperation with them.

  In the above embodiment, the fail-safe control process is executed by the brake control ECU 1, but the brake control ECU 1 is not necessarily required. In particular, when there is an integrated ECU or the like that integrally performs various controls in a vehicle that has been researched in recent years, the integrated ECU may perform the fail-safe control process. Further, the fail safe control process may be executed by a plurality of ECUs.

It is a figure which shows the block configuration of the parking assistance brake control apparatus in 1st Embodiment of this invention. It is a figure which shows the structure of the hydraulic brake with which a parking assistance brake control apparatus is equipped. It is the flowchart which showed the detail of the fail safe control process which brake control ECU performs. It is the flowchart which showed the detail of the fail safe control process which brake control ECU with which the parking assistance brake control apparatus in 2nd Embodiment of this invention is equipped is performed. It is the flowchart which showed the detail of the fail safe control process which brake control ECU with which the parking assistance brake control apparatus in 2nd Embodiment of this invention is equipped is performed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brake control ECU, 2 ... Hydraulic brake device, 3 ... PKB,
4FR, FL, RR, RL ... wheels, 5FR, FL, RR, RL ... wheel speed sensors,
6 ... In-vehicle LAN bus, 7 ... Engine control ECU, 8 ... Perimeter monitoring control ECU,
9 ... Warning display / alarm device, 50 ... Sensors, 55 ... Door open / close sensor, VL ... Vehicle.

Claims (8)

In a parking assistance brake control device that executes parking assistance brake control for controlling the speed of the vehicle with a braking force when a parking assistance mode for assisting parking of the vehicle (VL) is set for the driver,
In the parking assist brake control, the abnormal state of the first brake means (2) that can apply the braking force to each wheel (4FL, 4FR, 4RL, 4RR) provided in the vehicle regardless of the driver's intention. An abnormality detection means (103) for receiving a detection signal indicating and detecting that an abnormality has occurred in the first brake means;
When the abnormality detecting means detects that an abnormality has occurred in the first brake means, a second brake means (3 different from the first brake means for applying a braking force to a wheel provided in the vehicle is provided. And a vehicle braking control means (115) for causing the vehicle to travel or stop at a predetermined speed by generating an instruction signal and generating a braking force. . Receiving a data indicating the vehicle speed of the vehicle, and having a target deceleration detecting means (109) for obtaining a target deceleration based on the data indicating the vehicle speed;
The vehicle braking control means outputs the instruction signal so as to obtain the target deceleration obtained by the target deceleration detecting means by controlling the braking force applied to the wheel by the second brake means. The parking assist brake control device according to claim 1, wherein the second brake means adjusts a braking force applied to the wheel. Deceleration increasing gradient detecting means (109) which receives data indicating the vehicle speed of the vehicle and obtains a deceleration increasing gradient based on the data indicating the vehicle speed;
The vehicle braking control means controls the braking force applied to the wheel by the second brake means so as to obtain the deceleration increasing gradient determined by the deceleration increasing gradient detecting means. The parking assist brake control device according to claim 1 or 2, wherein the parking assist brake control device outputs and adjusts a braking force applied to the wheel by the second brake means. The vehicle braking control means outputs an instruction signal to the second brake means to generate a braking force or outputs an instruction signal to the second brake means according to the place where the abnormality of the first brake means has occurred. The parking assist brake control device according to any one of claims 1 to 3, wherein whether the braking force is generated by the first brake means is changed without outputting. In the case where the first brake means is configured to add the braking force by dividing the wheel provided in the vehicle into two systems,
The vehicle braking control means does not output an instruction signal to the second brake means when the location where the abnormality of the first brake means occurs is only one of the two systems. The parking assist brake control device according to claim 4, wherein a braking force is generated by the first brake means. The vehicle braking control means outputs an instruction signal to the second brake means and generates a braking force by the second brake means when an abnormality occurs in both systems of the first brake means. 6. The parking assist brake control device according to claim 5, wherein The parking assist brake control device according to any one of claims 1 to 6, wherein the vehicle brake control means outputs the instruction signal to an electric parking brake as the second brake means. A parking assistance brake control program for causing a computer to execute a function of controlling the speed of the vehicle with a braking force when a parking assistance mode for assisting the driver in parking the vehicle (VL) is set. ,
A detection signal indicating an abnormal state of the first brake means (2) for applying the braking force to the wheels (4FL, 4FR, 4RL, 4RR) provided in the vehicle regardless of the driver's intention is received, and the first An abnormality detection function for detecting that an abnormality has occurred in the brake means;
The first brake that applies a braking force to each wheel (4FL, 4FR, 4RL, 4RR) provided in the vehicle when the abnormality detecting means detects that an abnormality has occurred in the first brake means. A vehicle braking control function for outputting an instruction signal to a second brake means (3) different from the means and generating a braking force to cause the vehicle to run or stop at a predetermined speed. A parking assistance brake control program.

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