JP2004050925A - Parking auxiliary brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and safely control the traveling condition of a vehicle leading to a stop of the vehicle without degrading drive feeling by assisting the driving operation of a driver when the vehicle is parked. <P>SOLUTION: A periphery monitor control ECU 8 calculates the braking distance L according to the distance from a detected obstacle. A brake control ECU 1 calculates the target deceleration according to the braking distance L and the vehicle speed to obtain a required braking value, compares the braking force required for the traveling at a target speed of a creep speed or the like with the required braking value, selects the larger required braking value (the target braking force), and generates this target braking force in a brake device. The vehicle can be automatically stopped (in a vehicle stopping mode) along the intention of a driver at a position approaching the obstacle after the traveling at the target speed (at a constant speed mode) according to the traveling circumstances such as the vehicle speed, the braking operation, and the accelerating operation and the distance from the obstacle. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic brake device for a vehicle, and more particularly, to a brake device that operates auxiliary when parking.
[0002]
2. Description of the Related Art
Conventionally, there has been a device that reduces the throttle opening during parking or starting to prevent sudden starting, or that generates a large braking force to prevent collision with an obstacle (Japanese Patent Laid-Open No. 2000-136538). .
[0003]
However, since the throttle is throttled or the braking force is generated regardless of the distance to the obstacle, it is necessary to set the deceleration to be large in order to surely avoid a collision. Since the change in vehicle speed differs from the driver's intention or expectation, such as when the vehicle stops, the driving feeling is degraded.
[0004]
A system in which the front of the vehicle is monitored by a radar while the vehicle is running, an alarm is issued in accordance with the detected distance to an obstacle, or the vehicle is automatically braked to decelerate and stop the vehicle (Japanese Patent Laid-Open No. 52-124628). However, this does not assist the driver's driving operation during parking.
[0005]
The present invention has been made in view of the above circumstances, and is intended to assist a driver's driving operation at the time of parking and to easily and safely control a driving state of a vehicle to a stop without deteriorating a driving feeling. With the goal.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 includes a braking force applying means (2, 3) for applying a braking force to each wheel (4FR, 4FL, 4RL, 4RR) of the vehicle (VL); An engine control means (7) for controlling the output of an engine (70) of the vehicle; and a constant speed for operating the vehicle at a predetermined target speed or less by operating at least one of the braking force applying means and the engine control means. Speed limiter means (1) operating in a mode, peripheral monitoring means (8, 54) for detecting a distance from the vehicle to an obstacle and outputting a braking request value according to the distance, and the braking request value And a brake control means (1) operating in a stop mode for controlling the braking force applying means to apply a braking force to stop the vehicle.
[0007]
According to the present invention, the braking request value is determined in accordance with the distance between the vehicle and the obstacle detected by the surroundings monitoring means, and the vehicle whose traveling is controlled at a target speed or less set in the constant speed mode is controlled by this braking. Since the vehicle is stopped by the braking force applying means based on the required value, the vehicle can be automatically stopped with a good driving feeling for the driver regardless of the distance between the vehicle and the obstacle. .
[0008]
According to the present invention, as set forth in claim 2, the speed limiter outputs a braking request value to the brake control means for driving the braking force applying means, and the brake control means outputs the braking request value. Comparing the braking request value from the limiter means with the braking request value from the periphery monitoring means, and driving the braking force applying means based on the larger braking request value to generate a braking force, A constant speed mode or a stop mode can be operated.
[0009]
The braking force applying means generates a first braking force according to a first driving signal and changes the first braking force to zero by canceling the first driving signal. 1 brake means (2), and a second brake means (3) for generating a second braking force according to a second drive signal and maintaining the second braking force by releasing the second drive signal. be able to.
[0010]
The first brake means may be, for example, a hydraulic brake device that generates or cancels a first braking force by applying a brake hydraulic pressure to a wheel cylinder of each wheel in response to a driver's operation of a brake pedal, An electric brake device that generates or cancels the first braking force by directly moving the brake calipers of each wheel by a motor in response to a brake pedal operation can be used.
[0011]
Further, the second brake means generates, for example, a second brake force by operating a parking brake by a motor, and releases the drive signal of the motor to stop the second brake force. Can be used.
[0012]
When operating the braking force applying means, the speed limiter generates at least one of the first and second braking means to generate a braking force. Can be done.
[0013]
Further, the brake control means generates a first braking force by the first brake means based on the braking request value to stop the vehicle, and after the vehicle stops, The second drive signal can be released and the second braking force can be generated by the second brake means by the second drive signal.
[0014]
The invention according to claim 6, wherein the surroundings monitoring means calculates, as the braking request value, a target braking distance to which the vehicle should travel by the time the vehicle stops in the stop mode in accordance with the distance to the obstacle. It is characterized by.
[0015]
According to the present invention, a target braking distance, which is a distance to be moved by the time the vehicle stops during the stop mode, is calculated in accordance with the distance between the vehicle and the obstacle detected by the surrounding monitoring means. Is set as the braking request value, so that the braking force applying means operated by the brake control means can surely stop the vehicle at the target braking distance.
[0016]
In addition, the surroundings monitoring means can correct the braking request value according to one of a speed of the vehicle and a relative speed between the vehicle and an obstacle, as described in claim 7. It is possible to easily and safely stop the vehicle without deteriorating the driving feeling according to the situation at the time of parking, such as the distance to the obstacle or the speed of the vehicle.
[0017]
If the distance measurement range of the surrounding monitoring means is changed based on either the target speed set in the speed limiter means or the actual speed of the vehicle, as described in claim 8, When the speed is high, a long distance range can be measured. When the speed is low, a short distance range, that is, a high accuracy measurement can be performed.
[0018]
According to a ninth aspect of the present invention, the speed limiter means calculates the target speed by a driving operation amount indicating a driving operation of a driver, a road surface state amount indicating a road surface state of a traveling road surface of the vehicle, and the periphery monitoring unit. The correction is performed based on at least one of the detected distances to the obstacle.
[0019]
According to the present invention, the target speed is corrected based on the driving operation amount, the road surface state amount, or the distance to the obstacle, so that the operation in the constant speed mode can be performed without deteriorating the driving feeling according to the situation at the time of parking. It can be carried out.
[0020]
In the case where the braking force applying means includes a plurality of braking means, when an abnormality such as a failure occurs in one of the braking means, the operation of the braking means, that is, the generation of the braking force is stopped, and A braking force is applied to each wheel by the brake means.
[0021]
That is, as described in claim 10, when the one of the braking means provided in the braking force applying means fails during the operation in the constant speed mode, the other of the other braking means is provided. The operation in the constant speed mode can be continued by switching to driving of the means.
[0022]
Further, as described in claim 11, when the one of the braking means provided in the braking force applying means fails during the operation in the stop mode, the other braking means is provided. , And the operation in the stop mode can be continued.
[0023]
According to a twelfth aspect of the present invention, after the vehicle stops, the final parking system operates in a stop position correction mode in which the vehicle is moved until the distance to the obstacle is equal to the set distance to the final parking completion position. It is characterized by further comprising a completed position correcting means (1).
[0024]
According to the present invention, the final parking completion position correcting means operates in the stop position correction mode to further move the vehicle from the state where the vehicle is stopped in the stop mode to the preset final parking completion position, The vehicle can be stopped at the parking completion position.
[0025]
According to a thirteenth aspect of the present invention, there is provided a moving amount detecting means (1, 5) for detecting a moving amount of the vehicle, wherein the final parking completion position correcting means is provided by the surrounding monitoring means from the vehicle to the obstacle. Operating the engine control means and / or the braking force applying means to move the vehicle until the distance of the vehicle becomes equal to the distance from the vehicle to the final parking completion position by the movement amount detecting means. it can.
[0026]
The moving amount detecting means calculates a moving amount of the vehicle based on a detected value of a distance from the vehicle to an obstacle by the surrounding monitoring means and sets the calculated moving amount as a detected value of the moving amount. be able to.
[0027]
In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means described in embodiment mentioned later.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
A parking assist brake device according to an embodiment of the present invention will be described with reference to the drawings.
[0029]
The parking assist brake control mode, which is an operation mode of the parking assist brake device of the present embodiment, includes a constant speed mode in which the vehicle travels at a low speed equal to or lower than the target speed at the time of parking. A stop mode in which the vehicle is stopped at a predetermined position by controlling the braking force in accordance therewith, and a stop position correction mode in which after the vehicle is stopped in the stop mode, the vehicle is further driven to a set final parking completion position and stopped at the final parking completion position. including.
[0030]
The first embodiment relates to a parking assist brake device that operates in a constant speed mode and a stop mode, and in a second embodiment described later, operates in a constant speed mode and a stop mode, and then operates in a stop position correction mode. And a parking assist brake device.
[0031]
FIG. 1 is a diagram showing the overall configuration of the present embodiment, which can be used commonly for the first and second embodiments. In the figure, a front right wheel, a front left wheel, a rear right wheel, and a rear left wheel of the vehicle VL are represented by FR, FL, RR, and RL, respectively.
[0032]
In the present embodiment, a brake control ECU 1 as brake control means, a hydraulic brake device 2 as first brake means, a hydraulic brake device 2, a first piping system 11, and a second piping system mounted on the vehicle VL 21, wheel cylinders (hereinafter referred to as W / C) 41FR, 41RL, 41FL, and 41RR for each of the wheels 4FR, 4RL, 4FL, and 4RR diagonally connected, and an electric parking brake (hereinafter, referred to as a second brake unit). PKB 3), brake wires 31R and 31L for connecting the PKB 3 to the brake calipers of the rear wheels 4RL and 4RR, respectively, and wheel speed sensors 5 (5FR, 5RL, 5FL and 5RR) for detecting the rotation speed of each wheel. , An in-vehicle LAN bus 6 for transmitting input / output signals of various electronic devices, and front left and right wheels An engine (E / G) 70 that rotationally drives FR and 4FL via axles 72R and 72L and an automatic transmission (AT) 71, respectively, an engine control ECU 7 as engine control means for controlling the output of the E / G 70, A periphery monitoring control ECU 8 as a periphery monitoring means, a lamp / warning device 9 including various lamps such as a hazard lamp and a warning device such as a buzzer, a steering amount sensor 51 for detecting a steering amount of a steering wheel, and detecting an operation amount of an accelerator pedal. A sensor means 50 including an accelerator operation amount sensor 52, a brake operation amount sensor 53 for detecting an operation amount of a brake pedal, and an obstacle sensor 54 for detecting an obstacle around the vehicle VL, and outputs a braking request to the brake control ECU 1. Braking provided with a traffic jam following ECU 81, a headway control ECU 82, and a drowsiness prevention ECU 83 And a calculated output unit 80.
[0033]
The hydraulic brake device 2 as the first brake means and the PKB 3 as the second brake means correspond to the braking force applying means, and the brake control ECU 1 operates as a speed limiter in a constant speed mode described later.
[0034]
The brake control ECU 1, the engine control ECU 7, the periphery monitoring control ECU 8, the lamp / alarm device 9, the sensor means 50, and the braking request output means 80 are respectively connected to the in-vehicle LAN bus 6, and each of which is connected to the in-vehicle LAN bus 6. Is sending and receiving.
[0035]
The AT 71 is a known device having a built-in torque converter that transmits the rotation of the E / G 70 to the axles 72R, 72L, and is controlled by a control device (not shown). In particular, in the first embodiment, the parking assist brake control is performed by positively utilizing the state in which the vehicle travels at a low speed due to the creep phenomenon (hereinafter, referred to as creep traveling). Therefore, the description of the control device of the AT 71 will be omitted. .
[0036]
The brake control ECU 1 is composed of a computer, and receives a wheel speed from a wheel speed sensor 5, a braking request from the periphery monitoring control ECU 8 and a braking request output unit 80 via the in-vehicle LAN bus 6, and a signal from various sensors 5 and 50. And outputs a drive signal for controlling the hydraulic brake device 2 and the PKB 3, which will be described later, and a signal for adjusting the output of the E / G 70 to the engine control ECU 7.
[0037]
Here, the hydraulic brake device 2 which is the first brake means constituting the braking force applying means will be described with reference to FIG.
[0038]
When a driver depresses a brake pedal (not shown), a master cylinder (hereinafter, referred to as M / C) 10 generates an M / C pressure corresponding to the depression force of the brake pedal detected by the brake operation amount sensor 53, and generates a M / C pressure. It is transmitted to the W / Cs 41FR, 41RL and 41FL, 41RR provided on each wheel via the first piping system 11 and the second piping system 21 to generate a first braking force.
[0039]
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.
[0040]
Note that the anti-skid control (hereinafter, referred to as ABS control) is executed by the brake control ECU 1 by a known control method, and a detailed description thereof will be omitted.
[0041]
In the first piping system 11, pressure increase control valves 14a and 14b are provided for the right front wheel 4FR and the left rear wheel 4RL, respectively, for adjusting the pressure increase and holding of the W / Cs 41FR and 41RL during the ABS control. I have. Further, check valves 141a and 141b are provided in parallel with the pressure increase control valves 14a and 14b, respectively, and when the W / C pressure becomes excessive when the pressure increase control valves 14a and 14b are shut off, the liquid flow is increased by M / C10. It is designed to escape to the side.
[0042]
The pressure-reducing pipe 12 extending from between the pressure-increasing control valves 14a, 14b and the W / C 41FR, 41RL is provided with pressure-reducing control valves 15a, 15b for adjusting the pressure reduction and holding of the W / C 41FR, 41RL in the ABS control. . The pressure reducing line 12 is connected to a reservoir 16.
[0043]
The brake fluid stored in the reservoir 16 is pumped up by a pump 17 driven by a motor 20 and discharged to the first piping system 11. The discharge destination is between the pressure increase control valves 14a and 14b and a master cut valve 18 described later. The motor 20 also drives the pump 27 in the second piping system 21. Note that a check valve 171 is provided at the discharge port of the pump 17.
[0044]
A master cut valve (hereinafter, referred to as an SM valve) 18 is arranged 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 shut off by a check valve in the illustrated direction when energized. In this shut-off state, the pressure is released when the pressure on the W / C 41FR, 41RL side becomes higher than the cracking pressure by the spring of the check valve on the M / C 10 side, thereby releasing the pressure. The SM valve 18 is provided with a check valve 181 in parallel, and allows only the flow from the M / C 10 side to the W / C 41FR, 41RL side.
[0045]
The suction line 13 connects between the M / C 10 and the SM valve 18 and the reservoir 16.
[0046]
A hydraulic pressure sensor 30 is provided between the M / C 10 and the SM valve 18 in the first piping system 11, and detects the pressure generated by the M / C 10. This pressure is the pressure generated in the secondary chamber (not shown) of the M / C 10. However, since the same pressure is also generated in the primary chamber to which the second piping system is connected, the hydraulic pressure sensor 30 is substantially M / C Detect pressure. Further, hydraulic pressure sensors 19a and 19b are provided between the pressure increase control valves 14a and 14b and the W / Cs 41FR and 41RL, respectively, and detect W / C pressures respectively. Output signals of these oil pressure sensors are input to the brake control ECU 1.
[0047]
The pressure increase control valves 14a and 14b and the pressure decrease control valves 15a and 15b are two-position valves. When the brake pedal is not operated and when the power is turned off (OFF) such as during normal braking, the illustrated valve body position, that is, the pressure increase The control valve is in a communicating state, and the pressure reducing control valve is in a cut-off (cut) state. Further, the SM valve 18 is also in the illustrated valve body position, that is, in the communicating state during normal non-energization.
[0048]
Each of these control valves is operated by an operation signal from the brake control ECU 1. Further, the motor 20 that drives the pumps 17 and 27 also operates according to an operation signal from the brake control ECU 1.
[0049]
Each operation signal for the hydraulic brake device 2 generally corresponds to a first drive signal. To stop the control of the hydraulic brake device 2 (or to prohibit the control), the first drive signal is set to 0 (non-operating state), specifically, the pressure increase control valves 14a, 14b, 24a, 24b, pressure reduction control 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 set to zero. Therefore, the hydraulic brake device 2 corresponds to a first brake unit that releases the braking force (braking force = 0) when the first drive signal is released.
[0050]
A basic control method of the hydraulic brake device 2 will be described.
[0051]
In a normal brake operation when the driver depresses the brake pedal, all control valves (SM valve 18, pressure increase control valve 14a, pressure decrease control valve 15a) are de-energized (OFF), and M / C The pressure acts directly on W / C, and W / C pressure = M / C pressure.
[0052]
During the ABS control, the operation is different between the process of reducing the W / C pressure to avoid tire lock and the process of increasing the W / C pressure to recover the braking force. The SM valve 18 is normally turned off (communication state) during the ABS control, and drives the pump 17 to suck the brake fluid from the reservoir 16.
[0053]
In the pressure reducing process of the ABS control, the communication / cut switching is repeated by setting the pressure increasing control valve 14a to the energized state (ON), that is, the cutoff state, and controlling the pressure reducing control valve 15a to the ON / OFF duty ratio. As a result, the brake fluid flows from the W / C 41FR into the reservoir 16 at a predetermined gradient, and the W / C pressure is reduced.
[0054]
In the pressure increasing process of the ABS control, the communication / cut switching is repeated by setting the pressure reducing control valve 15a to a non-energized state (OFF), that is, a cut state, and controlling the pressure increasing control valve 14a to an OFF / ON duty ratio. Thus, the brake fluid is supplied from the M / C 10 to the W / C 41FR, and the W / C pressure is increased.
[0055]
Next, the parking assist brake control of the present invention, that is, the brake control ECU 1 sends the hydraulic brake device 2 to the hydraulic brake device 2 based on the braking request signal from the periphery monitoring control ECU 8 and the braking request output means 80 regardless of whether or not the brake pedal is depressed. The pressure increasing process and the pressure decreasing process during the braking operation instructed will be described.
[0056]
In the pressure increasing process of the parking assist brake control, the SM valve 18 is turned on (cut state), the pressure reducing control valve 15a is turned off (cut state), and the pump 17 is driven to suck the brake fluid from the reservoir 16. In the state where the discharge pressure is generated, the pressure increase control valve 14a is turned on or off at a predetermined change gradient by the duty ratio control of OFF / ON while comparing with the detection value of the hydraulic pressure sensor 19a, or the set target value. Increase W / C pressure to pressure. At this time, the brake fluid is replenished from the M / C 10 to the suction port of the pump 17 via the suction line 13 and the reservoir 16 as necessary.
[0057]
In the pressure reduction 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 the brake fluid from the reservoir 16. In the state where the discharge pressure is generated, the pressure reduction control valve 15a is turned on / off at a predetermined gradient by the ON / OFF duty ratio control or up to the set target pressure while comparing with the detection value of the hydraulic pressure sensor 19a. The W / C pressure is reduced by sucking the brake fluid from the W / C 41FR. 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 becomes larger than the cracking force of the spring of the check valve of the SM valve 18. Pressure drops.
[0058]
Next, PKB3 which is the second brake means will be described.
[0059]
The PKB 3 has a braking force, i.e., a braking force, that is, an actuator composed of a motor and a gear mechanism (not shown) that operates according to a second drive signal from the brake control ECU 1 and drives the brake calipers of the left and right rear wheels 4RR and 4RL via the brake wires 31R and 31L. , A second braking force is generated. The motor of the PKB 3 is duty-driven based on the second drive signal to rotate forward or reverse, thereby controlling the magnitude of the second braking force.
[0060]
At this time, a braking force corresponding to the duty ratio is generated, and when the target braking force is reached, the motor of the PKB 3 is locked, and when the motor lock is detected, the drive current of the motor is cut off, that is, the second drive signal is released. As a result, the PKB 3 enters a control stopped (control prohibited) state. Since the gear mechanism does not move in the PKB 3 control stopped state, the second braking force is maintained and the locked state is established.
[0061]
The operation of the PKB 3 is not only performed by the second drive signal from the brake control ECU 1 during the parking assist brake control, but also based on the operation signal when the driver turns on / off a parking brake switch (not shown). The brake control ECU 1 can operate by outputting a second drive signal of the PKB 3.
[0062]
As shown in FIG. 2, the wheel speed sensors include wheel speed sensors 5FR, 5FL, 5RR, and 5RL that detect the rotation speed of each wheel, and their output signals are directly input to the brake control ECU 1. By using a semiconductor type speed sensor using a hall element for the wheel speed sensors 5FR, 5FL, 5RR and 5RL, a reliable wheel rotation pulse can be obtained even at a low speed, so that an accurate vehicle speed can be detected even at a parking speed. it can.
[0063]
The engine control ECU 7 adjusts the fuel injection amount according to the running state based on the accelerator opening signal, which is the accelerator operation amount from the accelerator operation amount sensor 52, the engine speed, the water temperature, the oxygen concentration in the exhaust gas, and the like. The engine output is controlled by giving a command value to 70.
[0064]
Further, in the first embodiment, the engine control ECU 7 increases the engine output from the idle state or decreases the output from the idle state to the idle state by the engine output adjustment signal from the brake control ECU 1 particularly at a low speed, and performs the brake control. The ECU 2 causes the vehicle VL to travel in the constant speed mode together with the control of the braking force. That is, the brake control ECU 1 and the engine control ECU 7 constitute the speed limiter of the present invention.
[0065]
As shown in FIG. 3, the obstacle sensor 54 measures a distance x to an obstacle existing in front of and behind the vehicle by a laser radar 541 provided at a front part and a rear part of the vehicle, for example, a bumper, and differentiates the distance x. The signal is sent together with the signal to the brake control ECU 1 and other braking request output means via the in-vehicle LAN bus 6. The differential signal of the distance x corresponds to a relative speed with respect to an obstacle such as a running vehicle ahead or behind.
[0066]
Note that the range of the measurement sensitivity of the obstacle sensor 54 is adjusted according to the vehicle speed as described later, and the distance measurement range (sensor sensitivity) increases as the vehicle speed increases.
[0067]
The periphery monitoring control ECU 8 calculates a braking distance L, which is a distance to a position where the vehicle VL should be stopped, based on the distance x to the obstacle measured by the obstacle sensor 54, and calculates the braking distance L as a braking request value. To the brake control ECU 1.
[0068]
The traffic congestion tracking ECU 81 detects the braking and stopping state of the preceding vehicle during traffic congestion, and performs a target deceleration for stopping or maintaining the following distance between the vehicle VL and the vehicle at a predetermined distance without colliding with the preceding vehicle. (For example, “deceleration of 0.23 G (G: gravitational acceleration)”) is calculated and output to the brake control ECU 1 via the in-vehicle LAN bus 6 as an ECU request value. The brake control ECU 1 converts the deceleration into braking pressure (braking oil pressure) by deceleration 1G = 10 MPa (Pa: pressure unit, Pascal) and evaluates the magnitude.
[0069]
The inter-vehicle control ECU 82 detects the distance and the relative speed between the host vehicle VL and an obstacle such as a preceding and following vehicle, 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 braking control by the brake control ECU 1 are performed so as to keep it. Further, in the present embodiment, a target braking distance (for example, “stop at 28 m”) is output to the brake control ECU 1 as the ECU request value. In addition, when the distance between the front and rear obstacles is suddenly reduced, there is a possibility that a pedestrian or the like may suddenly jump out in the vehicle traveling direction. Therefore, a braking request for enabling rapid braking is issued. Note that the distance to the front and rear obstacles can be detected by the obstacle sensor 54.
[0070]
The brake control ECU 1 calculates the target deceleration from the current vehicle speed and the target braking distance, or sets the maximum deceleration at the time of sudden braking, converts this to the braking pressure as described above, and evaluates the magnitude. .
[0071]
The dozing prevention ECU 83 detects the driving operation state or the driver's physiological state to determine 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 the present embodiment, the time change value of the target brake fluid 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.
[0072]
Next, the parking assist brake control mode, which is executed by the brake control ECU 1, the engine control ECU 7, and the surroundings monitoring control ECU 8, each of which is constituted by a computer, will be described with reference to a flowchart. The operations shown in the following flowcharts are executed in cooperation by the control ECUs.
[0073]
FIG. 4 is a main flowchart of the parking assist brake device of the first embodiment, which is repeatedly executed mainly by the brake control ECU 1 in each control cycle (5 to 10 ms).
[0074]
In the first embodiment, as described above, as the parking assist brake control, each operation of moving at a target speed or lower in the constant speed mode and stopping after moving the target braking distance in the stop mode is performed.
[0075]
The process is started when the ignition is turned on, and in step S100, various sensor input processes such as the wheel speed sensor 5, the M / C pressure sensor 30, the W / C pressure sensors 19 and 29, and the engine control by communication via the wireless LAN bus 6. An input process of information from other systems such as the ECU 7, the periphery monitoring control ECU, and the braking request output unit 80 is performed.
[0076]
In step S110, the input pulse from the wheel speed sensor 5 of each wheel is arithmetically processed to calculate the wheel speed of each wheel. Further, the vehicle body speed (vehicle speed) is calculated from the average value of the wheel speeds of the driven wheels (the left and right rear wheels in the present embodiment) among these wheel speeds.
[0077]
In step S120, as the brake control performed during normal running, the above-described ABS control is performed. When the wheel speed is higher than the vehicle speed and the slip amount is equal to or more than a predetermined value, the engine output and the braking force are controlled to reduce the slip amount. Traction (TRC) control and side skid prevention (VSC) control that detects lateral acceleration and yaw rate of the vehicle and controls the braking force of each wheel so that they become equal to or less than a predetermined value, that is, to ensure the stability of the vehicle body. , Respectively, depending on the driving situation.
[0078]
In step S130, according to the flow described later, for the operation in the constant speed mode in which the vehicle runs at a speed equal to or lower than the target vehicle speed, each of the operations for adjusting the engine output and the braking force so that the vehicle speed becomes equal to or lower than the preset target speed. Set the control command value.
[0079]
In step S140, as will be described later, the braking distance L as a braking request value from the periphery monitoring control ECU 8 is converted into a braking hydraulic pressure. The brake control ECU 1 treats the converted brake fluid pressure as a braking request value.
[0080]
In step S150, as will be described later, the braking request value of the periphery monitoring control ECU 8 is compared with the braking request value in the constant speed mode, and based on the larger braking request value, the hydraulic brake device 2 or Selection of which one of the PKBs 3 is to be driven and setting of the command value γ of the target braking force to be generated, that is, brake control arbitration is performed.
[0081]
In step S160, as a result of the brake control arbitration in step S150, a first drive signal is output to the hydraulic brake device 2 based on the set target control pressure for the hydraulic brake device 2 to generate a first braking force.
[0082]
In step S170, as a result of the brake control arbitration in step S150, a second drive signal is output to PKB3 based on the set target braking force for PKB3 to generate a second braking force.
[0083]
In step S180, the engine control command value set in step S130 (specifically, step S350 described later) is transmitted to the engine control ECU 7.
[0084]
In step S190, a failsafe check during ignition on is performed. That is, the states of the brake control ECU 1, the hydraulic brake device 2, the PKB 3, and other sensors are constantly diagnosed. When a failure is detected, predetermined measures are taken so that the vehicle VL does not enter a dangerous state.
[0085]
Next, a procedure for calculating the braking request value L from the surroundings monitoring control ECU 8 input in step S100 will be described.
[0086]
FIG. 5 is a calculation flow of the braking request value L by the periphery monitoring control ECU 8, which is repeatedly executed in a control cycle when the ignition is turned on.
[0087]
In step S200, the distance x from the obstacle sensor 54 to the obstacle is input.
[0088]
In step S210, based on the distance x to the obstacle and the vehicle speed, a braking distance L, which is a traveling distance from the current position (at the time of calculation) to a position where the vehicle should be stopped, is calculated. The relationship between x and L is set in advance as shown in FIG. The braking distance L is set so as to be longer in accordance with the distance x to the obstacle, and L is infinite above a predetermined distance, that is, the braking force is not generated.
[0089]
Further, the braking distance L is set to be shorter with the vehicle speed at the same distance x, that is, shifted to the right in FIG. If the detected obstacle is a vehicle traveling forward or backward, the braking distance L shown in FIG. 6 is corrected by the relative speed between the own vehicle VL and those traveling vehicles instead of the above vehicle speed. Is also good.
[0090]
As described above, the distance measurement range (sensor sensitivity) of the obstacle sensor 54 is switched to be longer according to the vehicle speed (see FIG. 7). Thus, at a low speed, a short distance range around the vehicle can be accurately measured, and at a high speed, a distance to a position far from the vehicle can be measured.
[0091]
In step S220, the calculated braking distance L is transmitted to the brake control ECU 1 as a braking request value.
[0092]
FIG. 8 shows a setting flow of each control command value of the engine output and the braking force for performing the operation in the constant speed mode, which is the processing content of the constant speed control in step S130.
[0093]
In step S300, the traveling direction of the vehicle is determined. Specifically, forward or backward is determined from a signal from a shift lever position sensor (not shown) provided for the shift lever of the AT 71. If the vehicle is moving forward, the process proceeds to step S310, and if the vehicle is moving backward, the process proceeds to step S320.
[0094]
In step S310, the target speed TVc is set by Expression 1.
[0095]
(Equation 1)
TVc = TVc + K1 (α) -max (K2 (β), K3 (γ))
Here, TVc is a target speed, and for example, 7 km / h, which is equivalent to the creep speed of an AT car on flat ground, is set in advance as an initial value.
[0096]
Further, as shown in FIG. 9, K1 (α) is a correction value that increases as the gradient increases on the descending gradient side and is set to 0 on the ascending gradient side, as shown in FIG. .
[0097]
K2 (β) is set so as to increase as β increases as shown in FIG. 10 in accordance with the brake operation amount (depressing amount of the brake pedal or pedal depression force) β from the brake operation amount sensor 53. This is the corrected value.
[0098]
Further, K3 (γ) is determined according to the command value γ for generating the target braking force applied to the hydraulic brake device 2 or the PKB 3 as the braking force applying means set in step S150, as shown in FIG. This is a correction value set to increase in proportion to γ. This γ is the control amount of the automatic brake, that is, the target braking force when the braking force is automatically generated during the parking assist brake control regardless of the operation of the brake pedal by the driver.
[0099]
In Expression 1, max (K2, K3) is an operator that sets K2 when K2 ≧ K3 and K3 when K2 <K3.
[0100]
In addition, as described in Japanese Patent Application Laid-Open No. 2000-6691, for example, the road surface gradient α is a running resistance calculated based on a vehicle weight and a longitudinal acceleration (differential value of a vehicle speed) during running, an engine output, and It can be estimated by calculation from the drive torque required to drive the wheels calculated from the AT gear ratio. Note that the inclination angle from the horizontal plane may be directly measured by the inclinometer, and the gradient α may be determined from the measured value.
[0101]
According to Equation 1, the target speed TVc is set so as to decrease in accordance with the brake operation amount β or the target braking force γ when the vehicle is moving forward, and to increase in accordance with the gradient α when the vehicle is descending.
[0102]
On the other hand, in step S320, the target speed TVc is set by Expression 2 using the correction values K1 and K2.
[0103]
(Equation 2)
TVc = TVc−K1 (α) −max (K2 (β), K3 (γ))
According to Expression 2, the target speed TVc is set so as to decrease in accordance with the brake operation amount β or the target braking force γ when the vehicle retreats, and to decrease in accordance with the gradient α when descending.
[0104]
By the steps S310 and S320, the target speed TVc in the constant speed mode can be adapted to the relationship between the traveling direction in the traveling state and the road surface inclination and the driver's braking operation feeling.
[0105]
Further, since the target speed TVc is corrected according to the control amount γ of the automatic brake as shown in Expressions 1 and 2, not only the brake operation by the driver's brake operation (operation amount = β) but also the automatic brake Even during the control, a correction for lowering the target speed in the constant speed traveling control can be executed, and the braking and acceleration (engine output increase) can be arbitrated.
[0106]
In step S330, a deviation ΔV between the set target speed TVc and the actual vehicle speed Vs0 is calculated.
[0107]
In step S340, an engine output and a braking force to be generated to make the deviation close to 0 are determined by PID calculation based on the deviation ΔV.
[0108]
In step S350, an engine control command value as a required throttle opening (or a throttle opening request flag for requesting a constant throttle opening operation) is set based on the target value of the engine output determined in step S340. .
[0109]
In step S360, a braking request value (target hydraulic pressure) γ to be applied to the hydraulic brake device 2 or the PKB 3 is calculated from the braking force determined in step S340 and set as a brake control command value.
[0110]
Next, the procedure for converting the braking request value L from the periphery monitoring control ECU 8 to the braking fluid pressure TPm performed in step S140 will be described. FIG. 12 shows the conversion processing flow.
[0111]
In step S400, the deceleration (target deceleration) Tg when stopping at the braking distance L from the current vehicle speed Vs0 is calculated by Expression 3.
[0112]
[Equation 3]
Tg = (Vs0) ² / (2L)
In step S410, the target hydraulic pressure TPm is calculated from the preset relationship between the target deceleration Tg and the target hydraulic pressure TPm shown in FIG.
[0113]
The brake control ECU 1 treats the target hydraulic pressure TPm as a braking request value from the periphery monitoring control ECU 8 (step S420).
[0114]
Next, a control flow (FIGS. 14, 15, and 16) of the brake control arbitration executed in step S150 will be described.
[0115]
First, in step S500, the braking request value (TPm) from the periphery monitoring control ECU 8 is compared with the braking request value in the constant speed mode set in step S360, and the larger one is selected.
[0116]
In step S510, it is determined whether or not the vehicle is stopped or is in a state immediately before the stop (referred to as a stopped state) based on the wheel speed, which is one of the information indicating the running state. Move to step S600.
[0117]
In step S520, it is determined whether or not the hydraulic brake device 2 is normal based on the result of the various input processes in step S100. If YES, the process proceeds to step S530, and if NO, the process proceeds to step S540.
[0118]
In step S540, it is determined whether PKB3 is normal. If NO, the process proceeds to step S550, and if YES, the process proceeds to step S560.
[0119]
In step S560, since the hydraulic brake device 2 is abnormal and the PKB 3 is normal, control of the hydraulic brake device 2 is prohibited, that is, the first drive signal is set to a non-operating state (drive current of each part = 0).
[0120]
Next, in step S570, the brake control ECU 1 sets a drive duty required to generate the required braking force, which is the ECU required value selected in step S500, as the target braking force of PKB3.
[0121]
In step S580, it is determined whether the braking force in which PKB3 is generated is equal to the set target braking force.
[0122]
This is determined by detecting that the motor of the PKB 3 has locked, that is, that the motor current has stopped increasing or that the rotation of the motor has stopped. If they are not equal, this routine is repeated until they are equal. If they are equal, the process proceeds to step S590 to end the control of PKB3.
[0123]
By the end of the control of the PKB 3, the driving force of the motor of the PKB 3 becomes 0, but the tension of the cable 31, that is, the braking force is maintained.
[0124]
If it is determined in step S540 that PKB3 is also abnormal, in step S550, the brake control ECU 1 prohibits the control of both the hydraulic brake device 2 and the PKB3, that is, deactivates all the first drive signals to the hydraulic brake device 2. State and the second drive signal to the PKB 3 is deactivated.
[0125]
On the other hand, if it is determined in step S520 that the hydraulic brake device 2 is normal, in step S530, the braking pressure (target control pressure) to be generated by the hydraulic brake device 2 is set to the required braking force that is the ECU request value selected in step S500. (Braking oil pressure), and the hydraulic brake device 2 is pressure-controlled by increasing or decreasing the pressure so as to achieve the set target braking force.
[0126]
Next, a case where the vehicle is determined to be in the stopped state in step S510 will be described with reference to FIG.
[0127]
In step 600, it is determined whether or not PKB3 is normal. If not, the process proceeds to step S660. If it is normal, in step S610, the ECU selected as the target braking force of PKB3 in step S570 as in step S570. A drive duty that is a required braking force, which is a required value, is set.
[0128]
Next, in step S620, it is determined whether or not the braking force in which PKB3 is generated is equal to the set target braking force in the same manner as in step S580. If not, this routine is repeated until the braking force is equal. The process proceeds to step S630 to end the control of PKB3.
[0129]
If the target braking force set in step S610 is larger than the maximum generated braking force of PKB3, the process ends when the generated braking force of PKB3 reaches the maximum value, and the process proceeds to step S630.
[0130]
Thereafter, in step S640, it is determined whether the braking pressure of the hydraulic brake device 2 has become 0 based on the detection value of the hydraulic sensor 19, and if YES, the control of the hydraulic brake device 2 ends in step S710, and if NO, Since the braking pressure by the hydraulic brake device 2 remains, the process proceeds to step S650 to reduce it to zero.
[0131]
In step S650, the target braking pressure of the hydraulic brake device 2 is lowered and reset by a predetermined value a, and the generated braking pressure is gradually reduced to 0 by repeating the above loop.
[0132]
When it is determined in step S660 that the hydraulic brake device 2 is normal, the PKB 3 is abnormal, and the control of the PKB 3 is prohibited in step S680.
[0133]
Next, in step S690, it is determined whether the control time of the hydraulic brake device 2, for example, the continuous energization time to the solenoid of each control valve of the hydraulic brake device 2 has exceeded a threshold value T. The threshold value T is given in advance as a value smaller than the continuous energizable time of the solenoid, which is determined in design in consideration of heat generation. If the result of determination is NO, control proceeds to step S700, where the same processing as in step S530 is performed, and if YES, hydraulic brake control ends in step S710.
[0134]
If the result of the determination in step S660 is NO, both the PKB 3 and the hydraulic brake device 2 are not normal, so that control of both is prohibited in step S670.
[0135]
As described above, in the control flow of the brake control arbitration, first, in step S500, a braking request value as a fluid pressure conversion value of the braking distance L calculated based on the distance to the obstacle and the vehicle speed output from the surrounding monitoring control ECU 8 is calculated. Then, a braking request value as a hydraulic pressure conversion value of a target braking force required for traveling at a constant speed in the constant speed mode is compared.
[0136]
As a result of this comparison, the larger braking force is selected (Step S150), and Step S160 or S170 is performed so that the target braking force set in Step S510 → S520 → S530 or S510 → S520 → S540 → S560-S590 is obtained. Then, one or both of the hydraulic brake device 2 and the PKB 3 are used to generate a braking force.
[0137]
That is, when the braking request value in the constant speed mode is selected, the vehicle speed is controlled to the target vehicle speed TVc in cooperation with the engine output control by the engine control ECU 1, while the braking request value from the periphery monitoring control ECU 8 is controlled. Is selected, the vehicle VL stops after moving by the target braking distance in the stop mode.
[0138]
At this time, if an abnormality occurs in the hydraulic brake device 2, in steps S540 → S560 to S590, a target braking force is generated by the PKB 3 instead of the hydraulic brake device 2, and in the constant speed mode or the stop mode. The operation is performed. If an abnormality has also occurred in the PKB 3, the control of both the hydraulic brake device 2 and the PKB 3 is stopped in steps S540 → S550.
[0139]
Then, when the braking request value from the periphery monitoring control ECU 8 is selected and the vehicle VL is stopped by the operation in the stop mode, the target control pressure of the hydraulic brake device 2 is increased by a in steps S600 to S650. A braking force is generated in the PKB 3 to keep the vehicle stopped while decreasing stepwise, and the vehicle speed = 0, that is, the vehicle is completely stopped.
[0140]
In this case as well, if an abnormality has occurred in the PKB 3, in steps S600, S660, S680, S690, S700, and S710, the hydraulic brake device 2 is used instead of the PKB 3 to stop with the predetermined energization time T as the upper limit. Generate braking pressure for maintenance. Further, when an abnormality has also occurred in the hydraulic brake device, in steps S660 → S670, control of both the hydraulic brake device 2 and the PKB 3 is stopped.
[0141]
As described above, in the parking assist brake device of the first embodiment, the braking force application including the hydraulic brake device 2 as the first braking device and the PKB 3 as the second braking device for applying the braking force to each wheel of the vehicle. Means, an engine control ECU 7 as an engine control means for controlling the output of the engine of the vehicle, a brake control ECU 1 for driving at least one of the hydraulic brake device 2, the PKB 3, and the engine control ECU 7, and a vehicle to an obstacle. And a periphery monitoring control ECU 8 which detects a distance of the vehicle and outputs a braking request value corresponding to a braking distance corresponding to the distance.
[0142]
Then, the brake control ECU 1 as a speed limiter corrects a preset target speed based on the road gradient α and the brake operation amount β or the target braking force γ in the automatic brake control to obtain a target speed. By comparing a braking request value corresponding to a target braking force necessary for running the vehicle with a braking request value from the peripheral monitoring control ECU 8, the hydraulic braking device 2 or the PKB 3 is determined according to the larger braking request value. By driving the vehicle, a braking force is generated on each wheel of the vehicle, and the vehicle is driven in the constant speed mode or stopped after the braking distance is moved in the stopped mode.
[0143]
Therefore, whatever the distance between the vehicle and the obstacle, that is, when the distance to the obstacle is relatively long, the operation in the constant speed mode corresponds to the brake operation amount and the road gradient. When the vehicle travels at the target speed and the distance to the obstacle becomes shorter, the operation in the stop mode causes the braking force applying means to apply a braking force to the vehicle so as to decelerate and stop the vehicle while traveling the braking distance L determined according to the vehicle speed. generate. This allows the vehicle to be adapted to a road surface condition such as a distance to an obstacle or a road surface gradient at the time of parking or the like, and according to the driver's braking operation intention without impairing the driver's driving feeling, Can be slowed down and stopped.
[0144]
(2nd Embodiment)
Next, a parking assist brake device according to a second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, as described above, after the vehicle is stopped by the operations in the constant speed mode and the stop mode, the vehicle is further driven to the set final parking completion position and stopped at the final parking completion position. The difference from the first embodiment is that the operation is performed in the stop position correction mode.
[0145]
Accordingly, the overall configuration of the second embodiment, the configuration of the hydraulic brake device 2 as the first brake means, and the configuration of the obstacle sensor 54 are the same as those shown in FIGS. 1, 2 and 3, respectively, and will be described. Is omitted. In the following, the points different from the first embodiment will be mainly described.
[0146]
FIG. 17 is a main flowchart of the parking assist brake device according to the second embodiment. Steps S100 to S120 perform the same processing as in the first embodiment.
[0147]
In step S125, the parking assist control is performed according to the flow shown in FIG.
[0148]
In this parking assist control, first, in step S132, the operation is performed in the constant speed mode by the same operation as in step S130 (FIG. 4), that is, steps S300 to S360 (FIG. 8). That is, an engine control command value for increasing the engine output so that the target vehicle speed TVc is corrected according to the road surface gradient α (FIG. 9) and the brake operation amount β (FIG. 10) according to the determined traveling direction, respectively. Alternatively, a brake control command value for generating a braking force is output.
[0149]
After that, in step S134, as the automatic stop control, the calculation of the braking distance L and the calculation of the brake fluid pressure from the braking distance L are performed according to the flow of FIG.
[0150]
Next, in step S136, after the vehicle VL is stopped by the operation in the stop mode, control for correcting the final parking completion position by further moving the vehicle according to the driver's intention is performed according to the flow of FIG. Execute.
[0151]
The automatic stop control flow of FIG. 19 will be described. In step S800, the same processing as in step S210 (FIG. 5) is performed, and the braking distance L is calculated according to the distance x from the surrounding monitoring control ECU 8 to the obstacle.
[0152]
In step S810, the same processing as in step S140 (FIG. 4), that is, steps S400 to S420 (FIG. 12) is performed, a target deceleration Tg is calculated from the vehicle speed Vs0 and the braking distance L, and the target deceleration Tg is plotted. The target brake fluid pressure is converted into a proportional relationship as shown in FIG.
[0153]
As described above, in the second embodiment, the processing procedure of calculating the braking distance L and converting the braking distance L into the braking fluid pressure is different from that of the first embodiment, but the processing contents are the same as those of the first embodiment. This is the same as the embodiment.
[0154]
Next, the final parking completion position correction control flow in step S136 will be described with reference to FIG.
[0155]
In step S900, it is determined whether the final parking completion position correction control has been completed based on the state of the position correction control completion flag. If the flag is ON, that is, if the correction control is completed, the process returns to RETURN, and if the flag is OFF, that is, if the correction control is not completed, the process proceeds to step S910.
[0156]
In step S910, it is determined whether or not the driver has input an intention to perform the position correction control using an input device such as a switch (not shown). In other words, in step S910, the driver who wants to “move to XX cm” or “close to the obstacle (for example, up to a distance of 10 cm)” from the position where the vehicle has stopped by the operation in the stop mode is called. It is determined whether the driver's intention to change the final parking completion position has been input.
[0157]
Specifically, the driver moves the current parking position from the current stop position to the final parking completion position assumed by the driver (for example, 50 cm), or separates from the obstacle as a correction position of the final parking completion position ( (For example, 5 cm) is determined.
[0158]
In addition, as described above, besides the value itself corresponding to the moving distance input by the driver, these distances are set in advance, and the driver is asked to “get closer to the obstacle (that is, only the set moving distance). "Move)" or "Move closer to the obstacle (i.e., move to the set separation distance)" may be input.
[0159]
In step S920, a target moving distance of the vehicle is calculated based on the input intention of the driver for the position correction control. Specifically, in the case of direct input of the movement distance that the user wants to move XX cm later, the input movement distance is set as the target movement distance in the stop position correction mode, and when the separation distance to the obstacle is input, The distance obtained by subtracting the input separation distance from the current stop position-inter-obstacle distance x by the obstacle sensor 54 is set as the target movement distance.
[0160]
In any case, in step S920, the target movement distance from the current position where the vehicle has stopped in the stop mode to the final parking completion position assumed by the driver is calculated by the correction input of the driver's final parking completion position. .
[0161]
Next, in step S930, the same process as in step S132 is performed to move the vehicle VL in the constant speed mode, and the actual movement distance of the vehicle VL is calculated from the rotation amount detected by the wheel speed sensor 5.
[0162]
Note that the vehicle speed at this time is set to a value smaller than the target speed in step S132, and is corrected to gradually decrease as the set target moving distance is reached.
[0163]
In step S940, it is determined whether or not the actual moving distance has become equal to or longer than the target moving distance set in step S920. If NO, the routine ends, and if YES, the process proceeds to step S950.
[0164]
In step S950, assuming that the driver's intention to correct the final parking completion position has been satisfied, a braking request value for stopping the vehicle VL is set by the processing in step S134, and the position correction control completion flag is set to ON. Then, this routine ends.
[0165]
With the execution of the above processing, the parking assist control flow in step S125 ends.
[0166]
In FIG. 17, in step S145, the respective braking request values from the other control ECUs, that is, the traffic congestion following ECU 81, the following distance control ECU 82, and the drowsiness prevention ECU 83 are converted into brake hydraulic pressure values by the same processing as in step S140.
[0167]
Step S155 is a processing step of brake control arbitration similar to step S150 in the first embodiment, and is performed on the hydraulic brake device 2 as the first brake means or the PKB 3 as the second brake means based on the selected braking request value. The control command value is set.
[0168]
The processing content in step S155 will be described according to the flow shown in FIG. In step S505, the braking request value from each control ECU is compared with the braking request value for parking assist set in step S125, and the largest braking request value is selected.
[0169]
Based on the braking request value selected here, control proceeds according to the flow shown in FIGS. 15 and 16 described in the first embodiment, and a control command value for the hydraulic brake device 2 and / or the PKB 3 is set.
[0170]
Hereinafter, as in the first embodiment, the processes of steps S160 to S190 are performed, a braking force is applied to each wheel of the vehicle VL, and parking assist control or braking control based on a braking request from another control ECU is performed. Be executed.
[0171]
As described above, when the distance between the front and rear obstacles is suddenly reduced, there is a possibility that a pedestrian or the like may jump out. Therefore, the inter-vehicle control ECU 82 issues a braking request for rapid braking (maximum braking force). Therefore, in step S505, the braking request for the sudden braking is selected, and in step S160 (or step S170), the vehicle VL can be suddenly stopped based on the request for the sudden braking.
[0172]
As described above, in the parking assist brake device of the second embodiment, the braking force application including the hydraulic brake device 2 as the first braking device and the PKB 3 as the second braking device for applying the braking force to each wheel of the vehicle. Means, an engine control ECU 7 as an engine control means for controlling the output of the engine of the vehicle, a brake control ECU 1 for driving at least one of the hydraulic brake device 2, the PKB 3, and the engine control ECU 7, and a vehicle to an obstacle. And a periphery monitoring control ECU 8 which detects a distance of the vehicle and outputs a braking request value corresponding to a braking distance corresponding to the distance.
[0173]
Then, the brake control ECU 1 as a speed limiter corrects a preset target speed based on the road gradient α and the brake operation amount β or the target braking force γ in the automatic brake control to obtain a target speed. A magnitude comparison between a braking request value corresponding to a target braking force necessary for running the vehicle and each braking request value from the periphery monitoring control ECU 8 and the other control ECUs such as the congestion following ECU 81, the following distance control ECU 82, and the dozing prevention ECU 83. By driving either the hydraulic brake device 2 or the PKB 3 according to the largest braking request value to generate a braking force on each wheel of the vehicle, the vehicle travels in the constant speed mode or after the braking distance moves in the stop mode. Stop the vehicle, and use the final stop completion position correction in the stop position correction mode to To run the fine stop.
[0174]
Therefore, whatever the distance between the vehicle and the obstacle, that is, when the distance to the obstacle is relatively long, the operation in the constant speed mode corresponds to the brake operation amount and the road gradient. When the vehicle travels at the target speed and the distance to the obstacle becomes shorter, the operation in the stop mode causes the braking force applying means to apply a braking force to the vehicle so as to decelerate and stop the vehicle while traveling the braking distance L determined according to the vehicle speed. generate. This allows the vehicle to be adapted to a road surface condition such as a distance to an obstacle or a road surface gradient at the time of parking or the like, and according to the driver's braking operation intention without impairing the driver's driving feeling, Can be slowed down and stopped.
[0175]
Further, when the driver intends to correct the final stop completion position so as to approach (or move away from) an obstacle in accordance with a driving situation or a situation around the vehicle by operating in the stop position correction mode, The vehicle can be moved and stopped as intended by the driver.
[0176]
(Other embodiments)
In the first and second embodiments, an example in which a hydraulic brake device as shown in FIG. 2 is used as the first brake means has been described. However, the present invention is not limited to this, and a so-called electric brake device may be used. This electric brake device converts the movement of the brake caliper of each wheel to linear motion instead of hydraulically generating the force to press the friction material provided on the brake caliper against the brake disc of each wheel to generate the braking force. It is generated by an electric motor via a mechanism. In this case, the electric motor is driven at a duty ratio corresponding to the target braking force by a drive signal (corresponding to a first drive signal) from the brake control ECU 1 to the electric motor.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a parking assist brake device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a hydraulic brake device as first brake means according to the embodiment of the present invention.
FIG. 3 is a diagram illustrating a configuration of an obstacle sensor according to the embodiment of the present invention.
FIG. 4 is a main flowchart showing the operation of the parking assist brake device according to the first embodiment of the present invention.
FIG. 5 is a flowchart illustrating a process of peripheral monitoring control performed by a peripheral monitoring control ECU according to the embodiment of the present invention.
FIG. 6 is a diagram illustrating a relationship between a distance x to an obstacle and a braking distance L.
FIG. 7 is a diagram illustrating a relationship between a vehicle speed and a distance measurement range of an obstacle sensor.
FIG. 8 is a flowchart showing a procedure for setting an engine and brake control command value in a constant speed mode according to the embodiment of the present invention.
FIG. 9 is a diagram showing a relationship between a correction value K1 of a target speed and a road surface gradient α.
FIG. 10 is a diagram showing a relationship between a target speed correction value K2 and a brake operation amount β.
FIG. 11 is a diagram illustrating a relationship between a target speed correction value K3 and a target braking force γ.
FIG. 12 is a flowchart showing a process of converting a target deceleration as a braking request value into a braking fluid pressure.
FIG. 13 is a diagram showing a relationship between a target deceleration and a brake hydraulic pressure.
FIG. 14 is a part of a flowchart showing a processing procedure of brake control arbitration according to the first embodiment of the present invention.
FIG. 15 is a part of a flowchart showing a processing procedure of brake control arbitration according to the embodiment of the present invention.
FIG. 16 is a part of a flowchart showing a processing procedure of brake control arbitration according to the embodiment of the present invention.
FIG. 17 is a main flowchart showing the operation of the parking assist brake device according to the second embodiment of the present invention.
FIG. 18 is a flowchart illustrating a procedure of parking assist control according to the second embodiment.
FIG. 19 is a flowchart illustrating a procedure of automatic stop control according to the second embodiment.
FIG. 20 is a flowchart illustrating a procedure of control for correcting a final parking completion position according to the second embodiment.
FIG. 21 is a part of a flowchart showing a processing procedure of brake control arbitration of the second embodiment.
[Explanation of symbols]
1 ... Brake control ECU, 2 ... Hydraulic brake device (second brake means),
3 ... PKB (second brake means), 31R, L ... brake wires,
4FR, FL, RR, RL: wheels, 5: wheel speed sensor, 50: sensor means,
51: steering amount sensor, 52: accelerator operation amount sensor,
53: brake operation amount sensor, 54: obstacle sensor, 6: in-vehicle LAN bus,
7 ... Engine control ECU, 70 ... Engine, 71 ... Automatic transmission,
72R, L: axle, 8: peripheral monitoring control ECU, 80: braking request output means,
81: traffic congestion control ECU, 82: headway control ECU,
83: doze prevention ECU, 9: lamp / alarm device,
10: M / C, 11, 21, ... piping system, 12, 22, ... decompression piping,
13, 23 ... suction pipe, 14, 24 ... pressure increasing control valve, 15, 25 ... pressure reducing control valve, 16, 26 ... reservoir, 17, 27 ... pump, 18, 28 ... master cut valve,
19, 29, 30 ... pressure sensor, 20 ... motor, 41 ... W / C.

Claims (14)

Braking force applying means for applying a braking force to each wheel of the vehicle,
Engine control means for controlling the output of the engine of the vehicle;
Speed limiter means operating in a constant speed mode in which at least one of the braking force applying means and the engine control means operates to cause the vehicle to travel at or below a preset target speed;
Peripheral monitoring means for detecting a distance from the vehicle to the obstacle and outputting a braking request value according to the distance;
A brake control unit that operates in a stop mode that controls the braking force applying unit to apply a braking force to stop the vehicle based on the braking request value;
A parking assist brake device comprising: The speed limiter unit outputs a braking request value to the brake control unit to drive the braking force applying unit,
The brake control means compares a braking request value from the speed limiter means with a braking request value from the periphery monitoring means, and drives the braking force applying means based on a larger braking request value to apply a braking force. 2. The parking assist brake device according to claim 1, wherein the parking assist brake device generates The braking force applying means generates a first braking force according to a first driving signal, and the first braking means changes the first braking force to zero by canceling the first driving signal; and a second driving signal. The parking assist according to claim 1 or 2, further comprising: a second brake means for generating a second braking force by the second brake signal and maintaining the second braking force by canceling the second drive signal. Braking device. The said speed limiter means drives at least one of the said 1st and 2nd brake means, and produces | generates a braking force, when operating the said braking force provision means. Parking assist brake device. The brake control means generates a first braking force by the first brake means based on the braking request value to stop the vehicle, cancels the first drive signal after the vehicle stops, and releases the second drive signal. The parking assist brake device according to claim 3, wherein the second braking means generates the second braking force according to a drive signal. 6. The braking request value according to claim 1, wherein the surrounding monitoring unit calculates a target braking distance to which the vehicle should travel before the vehicle stops in the stop mode according to a distance to the obstacle. The parking assist brake device according to any one of the above. 7. The parking assist brake device according to claim 6, wherein the surrounding monitoring unit corrects the braking request value based on one of a speed of the vehicle and a relative speed between the vehicle and an obstacle. 8. The apparatus according to claim 1, wherein the distance measurement range of the surrounding monitoring means is changed based on either a target speed set in the speed limiter means or an actual speed of the vehicle. The parking assist brake device according to claim 1. The speed limiter means sets the target speed as a driving operation amount indicating a driving operation of a driver, a road surface state amount indicating a road surface state of a traveling road surface of the vehicle, and a distance to the obstacle detected by the surrounding monitoring unit. The parking assist brake device according to any one of claims 1 to 8, wherein the correction is performed by at least one of the following. The speed limiter means switches to driving of the other brake means when the one brake means of the braking force applying means has a failure during operation in the constant speed mode, and switches to driving of the other brake means. The parking assist brake device according to claim 3, wherein the operation of (1) is continued. The brake control means switches to driving of the other brake means and continues the execution of the stop mode when the one brake means of the braking force applying means fails during the stop mode execution. The parking assist brake device according to claim 3, wherein: After the vehicle stops, the vehicle further includes a final parking completion position correction unit that operates in a stop position correction mode that moves the vehicle until the distance to the obstacle becomes equal to the set distance to the final parking completion position. The parking assist brake device according to any one of claims 1 to 11, wherein: A moving amount detecting unit that detects a moving amount of the vehicle, wherein the final parking completion position correcting unit detects that the distance from the vehicle to the obstacle by the peripheral monitoring unit is the last parking completion position from the vehicle by the moving amount detecting unit; The parking assist brake device according to claim 12, wherein the vehicle is moved by operating at least one of the engine control unit and the braking force applying unit until the distance to the position becomes equal to the position. 14. The moving amount detecting unit according to claim 13, wherein the moving amount of the vehicle is calculated based on a detected value of a distance from the vehicle to an obstacle by the surrounding monitoring unit, and the calculated moving amount is used as a detected value of the moving amount. The parking assist brake device as described in the above.

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