JP3666345B2 - Automatic travel control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic travel control device, and more particularly, an automatic travel control device in which acceleration / deceleration of a vehicle is continuously controlled and a limit value of the acceleration / deceleration is defined by a control system for acceleration or deceleration. Or an automatic travel control device that has a plurality of speed reduction means for giving a deceleration force to the vehicle, and that each speed reduction means is executed in order of increasing braking force on the vehicle, whereby the vehicle deceleration is controlled stepwise. It is about.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a technique for controlling a throttle and a brake so that a preceding vehicle and the host vehicle follow a predetermined distance between vehicles.
For example, in the vehicle constant speed traveling device disclosed in Japanese Patent Application Laid-Open No. 61-175130, the distance between the preceding vehicle and the host vehicle is detected by an ultrasonic radar or the like, and the distance between the vehicles and the amount of change in the distance between the vehicles are calculated. Based on this, the throttle valve drive device and the brake drive device are controlled.
[0003]
Moreover, in the automatic braking device for a vehicle described in Japanese Patent Application Laid-Open No. 5-310108, a brake is applied according to a deviation between the deceleration of the own vehicle and the target deceleration calculated from the relationship with the control object ahead. The pressure is controlled.
Also known is a constant speed travel control device that controls the throttle valve driving device in accordance with the deviation between the set vehicle speed and the actual vehicle speed to keep the vehicle speed constant.
[0004]
In such an automatic travel control device, a technique for defining an upper limit value and a lower limit value of acceleration / deceleration is also known.
For example, in a vehicle constant speed traveling device described in Japanese Patent Publication No. 2606218, when a braking hydraulic pressure is applied to a hydraulic actuator from a high hydraulic pressure source to decelerate the vehicle based on a vehicle deceleration command, the vehicle is decelerated. The upper limit value of deceleration is defined by limiting the upper limit value of the hydraulic pressure.
[0005]
[Problems to be solved by the invention]
The conventional automatic travel control device may give the driver a sense of incongruity associated with travel control, as exemplified below.
(1) When deceleration by the automatic travel controller has reached the upper limit.
[0006]
When the inter-vehicle distance between the preceding vehicle and the host vehicle decreases, the brake oil pressure is continuously applied by the brake drive unit according to the deviation between the target deceleration calculated from the inter-vehicle distance and relative speed and the actual deceleration (actual acceleration). The hydraulic pressure applied to the brake hydraulic actuator reaches the upper limit. In this case, the driver may not be able to grasp that the automatic travel control device cannot decelerate more than the deceleration at that time, and may misunderstand that the automatic travel control device further increases the deceleration.
[0007]
(2) When deceleration by the automatic travel controller has not reached the upper limit.
As a result of the reduction of the distance between the preceding vehicle and the host vehicle, the brake hydraulic pressure is continuously controlled by the brake driving device and the hydraulic pressure applied to the brake hydraulic actuator is increased in the same manner as in the above (1). The upper limit may not be reached yet. In this case, the driver cannot grasp that the automatic cruise control device can decelerate more than the deceleration at that time, and does not know whether the automatic cruise control device increases the deceleration. I'm hesitant about doing it. At this time, the driver does not know whether or not the automatic travel control device is functioning normally, and has a sense of anxiety, and has a feeling of fatigue due to difficulty in placing a foot for operating the brake pedal.
[0008]
(3) The acceleration by the automatic travel control device has reached the upper limit.
When the inter-vehicle distance between the preceding vehicle and the host vehicle increases, the engine output torque is continuously generated by the throttle valve drive device according to the deviation between the target acceleration calculated from the inter-vehicle distance and relative speed and the actual acceleration (actual acceleration). Controlled. As a result, when the target acceleration reaches the upper limit, the actual acceleration also reaches the upper limit following the target acceleration. In this case, the driver may not be able to grasp that the automatic travel control device cannot accelerate more than the acceleration at that time, and may misunderstand that the automatic travel control device further increases the acceleration. As a result, the driver's own throttle operation may be delayed and may be too far from the controlled object. At this time, the driver does not know whether or not the automatic travel control device is functioning normally, and feels uneasy.
[0009]
By the way, it may be possible to empirically determine whether the acceleration / deceleration by the automatic travel control device has reached the upper limit or the lower limit from the movement and experience of the indicator of the vehicle speedometer. However, it is usually difficult to determine the acceleration / deceleration from the movement of the indicator of the vehicle speedometer. In addition, when accelerating / decelerating from experience, it is often the case that the judgment is distorted depending on the external environment such as road gradient and weather, physical condition, and vehicle type. Therefore, the uncomfortable feeling associated with the traveling control of the automatic traveling control device cannot be wiped out even by the empirical judgment and may be promoted.
[0010]
By the way, in the inter-vehicle distance control device described in Japanese Patent Application Laid-Open No. 8-142717, based on the inter-vehicle distance between the host vehicle and the preceding vehicle, the relative speed, and the deceleration when the throttle is fully closed, the distance is within a predetermined distance from the preceding vehicle. The possibility of approach is predicted and the driver is notified of the possibility. The publication also discloses a technique based on deceleration and travel resistance generated during shift control in calculating the deceleration when the throttle is fully closed. Furthermore, the publication provides a limiter for limiting the brake pedal pressure, and based on the maximum deceleration, the inter-vehicle distance, and the relative speed at the time of control by the brake pedal pressure limited by the limiter, it is within a predetermined distance with respect to the preceding vehicle. Techniques for predicting the possibility of approach are also described.
[0011]
However, the technology described in the publication discloses the possibility of approaching the preceding vehicle within a predetermined distance from the inter-vehicle distance control device to the driver, and the prediction of the possibility is based on the sensitivity of the driver. Does not necessarily match, and the setting of the predetermined distance does not necessarily match the driver's intention. Therefore, with the technique described in the publication, it is not possible to eliminate the uncomfortable feeling felt by the driver in the cases of (1) to (3).
[0012]
The present invention has been made to solve the above problems, and an object of the present invention is to eliminate a sense of incongruity felt by the driver in connection with automatic traveling control.
[0013]
[Means for Solving the Problems]
  The invention according to claim 1, which has been made to achieve the object,
In an automatic travel control device that detects a value corresponding to an actual inter-vehicle distance between the own vehicle and a preceding vehicle and accelerates or decelerates the own vehicle so that a value corresponding to the actual inter-vehicle distance becomes a value corresponding to a target inter-vehicle distance. And a control means for obtaining a control target value for accelerating / decelerating the vehicle. Further, at least one of the control target value obtained by the control means, an operation amount corresponding to the control target value, or an actual acceleration of the host vehicle controlled based on the control target value.OrInforming means for informing the driver is provided.
[0014]
  Therefore, according to the present invention, at least one of the control target value, the operation amount corresponding to the control target value, or the actual acceleration of the host vehicle controlled based on the control target value.TheThe driver can recognize. For this reason, the driverIt is possible to accurately grasp the acceleration / deceleration capability of the vehicle, and to determine how much the automatic travel control device can accelerate / decelerate.The necessity of manual operation (brake operation or throttle operation) by the driver can be determined by himself. In other words, the driver's decision to accelerate or decelerate the vehicle depends on many factors surrounding the vehicle (for example, external environment such as road gradient and weather, physical condition, vehicle type, distance between the preceding vehicle and the following vehicle). Influenced by distance, speed of own vehicle, etc. Therefore, it is desirable that the driver himself can determine the transition timing from automatic travel control by the automatic travel control device to manual operation (brake operation or throttle operation) by the driver. According to the present invention, the acceleration / deceleration capability of the automatic travel control deviceIt is possible to accurately grasp the vehicle speed and determine how much the automatic cruise control device can accelerate or decelerate.Therefore, it becomes easy to determine the transition timing from the automatic traveling control to the manual operation by the automatic traveling control device. Therefore, the driver can wipe away the uncomfortable feeling associated with the travel control of the automatic travel control device.
[0015]
  Here, “the operation amount corresponding to the control target value” is, for example, the actual throttle opening if the control target value is the target throttle opening, and if the control target value is the target brake pressure, The actual brake pressureThe
[0023]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a schematic configuration of the automatic travel control device 2 of the present embodiment. The automatic travel control device 2 is mounted on an automobile equipped with a gasoline engine as an internal combustion engine, and a target inter-vehicle distance (hereinafter referred to as an actual inter-vehicle distance) between a preceding vehicle and the own vehicle (hereinafter referred to as an actual inter-vehicle distance). This is an apparatus that performs auto-cruise control to control the driving force and braking force of the host vehicle so as to coincide with the target inter-vehicle distance.
[0024]
The automatic travel control device 2 includes a front recognition sensor 3, an inter-vehicle distance control electronic control device (hereinafter referred to as an inter-vehicle distance control ECU) 4, an engine control electronic control device (hereinafter referred to as an engine control ECU) 5, The brake control electronic control device (hereinafter referred to as brake control ECU) 6 is mainly configured.
[0025]
The front recognition sensor 3 includes a known radar sensor or proximity sensor that uses ultrasonic waves, radio waves, lasers, infrared rays, or the like. For example, the radar sensor is configured with a scanning rangefinder and a microcomputer as the center. A scanning rangefinder scans and emits ultrasonic waves, radio waves, lasers, infrared rays, etc. within a predetermined angular range in the vehicle width direction, and based on the reflected wave or reflected light from the preceding vehicle, the traveling direction of the preceding vehicle relative to the own vehicle ( Traveling angle), the actual inter-vehicle distance between the preceding vehicle and the host vehicle, and the relative speed are detected. The microcomputer detects the traveling angle of the preceding vehicle detected by the scanning rangefinder, the actual inter-vehicle distance, the relative speed, the current speed of the own vehicle (hereinafter referred to as the current vehicle speed) and the curve curvature radius input from the inter-vehicle distance control ECU 4. Based on the above, the own lane probability of the preceding vehicle is calculated. Then, the front recognition sensor 3 determines the preceding vehicle information including information such as the traveling angle of the preceding vehicle, the actual inter-vehicle distance, the relative speed, the own lane probability of the preceding vehicle, and the diagnosis of the front recognition sensor 3 itself as the inter-vehicle distance. It outputs to control ECU4.
[0026]
Each of the ECUs 4 to 6 includes a known microcomputer having a CPU, a ROM, a RAM, and an I / O circuit. When an ignition switch (not shown) is turned on, power is supplied from an in-vehicle battery (not shown). . The ECUs 4 to 6 are connected to each other via a control system LAN (LOCAL AREA NETWORK) 7.
[0027]
The control LAN 7 is connected to the body LAN 9 through the gateway 8. A wiper switch 10, a tail switch 11, and a display device 12 are connected to the body LAN 9.
The wiper switch 10 is a switch for stopping auto cruise control when a wiper (not shown) is operated. That is, since it is difficult to obtain accurate preceding vehicle information by the front recognition sensor 3 during rain, auto-cruise control is not performed when the wiper is operated during rain. In particular, when a laser radar sensor is used as the front recognition sensor 3, it is difficult to obtain accurate preceding vehicle information because the progress of the laser is hindered by raindrops.
[0028]
When the road is dark, such as at night or when foggy fog occurs, the tail switch 11 corrects the target inter-vehicle time set by the driver with the cruise control switch 13 to a large value as will be described later. This is a switch for further reducing the possibility of contact.
[0029]
The display device 12 is provided on the instrumental panel and displays contents such as display data, diagnosis, and brake operation state, which will be described later.
The display device 12 is provided with a display 31 as a notification means for displaying the operation state of the automatic travel control device 2.
[0030]
A cruise main switch 23 and a cruise control switch 13 are connected to the inter-vehicle distance control ECU 4. The cruise main switch 23 is a power switch for activating the inter-vehicle distance control ECU 4. The cruise control switch 13 is used for the driver to set a time required for the host vehicle to travel a distance corresponding to the target inter-vehicle distance between the preceding vehicle and the host vehicle in auto-cruise control (hereinafter referred to as a target inter-vehicle time). It is a switch.
[0031]
The inter-vehicle distance control ECU 4 includes a target inter-vehicle time input from the cruise control switch 13, preceding vehicle information and diagnosis input from the front recognition sensor 3, throttle opening, current vehicle speed, and control state input from the engine ECU 5. (The idle control state, the shift position of the transmission, etc.), the steering angle and yaw rate input from the brake ECU 6, and the operation states of the wiper switch 10 and the tail switch 11 input via the LANs 7 and 9 and the gateway 8. The curve curvature radius and the target acceleration are calculated based on each signal, and each signal representing a fuel cut request, an overdrive (OD) cut request, a shift down request, a brake request, an alarm request, and display data is generated. .
[0032]
Then, the inter-vehicle distance control ECU 4 outputs signals representing the target acceleration, fuel cut request, overdrive cut request, and shift down request to the engine ECU 5 respectively, and brakes the signals representing the target acceleration, brake request, and alarm request, respectively. It outputs to ECU6 and each signal showing display data and a diagnosis is output to the display apparatus 12 via each LAN7 and 9 and the gateway 8, respectively.
[0033]
A throttle opening sensor 24, a vehicle speed sensor 14, and a brake switch 15 are connected to the engine ECU 5. The throttle opening sensor 24 detects an actual opening (hereinafter referred to as an actual throttle opening) of a throttle valve (not shown) of a gasoline engine. The vehicle speed sensor 14 detects the speed of the vehicle based on the rotational speed of each wheel (not shown) of the vehicle. The brake switch 15 detects whether or not the driver depresses a brake pedal (not shown).
[0034]
The engine ECU 5 represents each signal input from the throttle opening sensor 24, the vehicle speed sensor 14, and the brake switch 15, and the target acceleration, fuel cut request, overdrive cut request, and shift down request input from the inter-vehicle distance control ECU 4. Based on each signal, the throttle actuator 16, the transmission 17, and the injector 25 are driven and controlled.
[0035]
The throttle actuator 16 adjusts the opening of the throttle valve.
The actuator drive circuit of the throttle actuator 16 generates a drive signal for controlling a motor and a clutch provided in the actuator based on a drive command from the engine ECU 5. According to the drive signal, the forward / reverse rotation and rotational speed of the motor are controlled, and the opening / closing of the clutch is controlled, and the rotation of the motor is transmitted to the throttle valve of the engine via the clutch. As a result, the engine ECU 5 can adjust the driving force of the engine and can control the speed of the vehicle. The transmission 17 is a 5-speed automatic transmission, and the reduction ratio of the 4th speed is set to “1”, and the reduction ratio of the 5th speed is set to a value (for example, 0.7) smaller than the 4th speed. 4-speed + overdrive (OD) configuration.
[0036]
The injector 25 injects fuel into an intake manifold (not shown) of the engine.
Further, the engine ECU 5 calculates the current vehicle speed based on the above signals, sets an optimal control state (idle control state, transmission shift position, etc.), and sets the actual throttle opening, the current vehicle speed, and the control state. Each of the signals is output to the inter-vehicle distance control ECU 4, and a signal indicating the current vehicle speed is output to the brake ECU 6.
[0037]
A master cylinder (M / C) pressure sensor 18, a steering sensor 19, and a yaw rate sensor 20 are connected to the brake ECU 6. The master cylinder pressure sensor 18 detects the hydraulic pressure (master cylinder pressure) of the master cylinder of the brake device. The steering sensor 19 detects the steering angle of the vehicle. The yaw rate sensor 20 detects the yaw rate of the vehicle.
[0038]
The brake ECU 6 receives signals input from the master cylinder pressure sensor 18, the steering sensor 19, and the yaw rate sensor 20, signals indicating the target acceleration, brake request, and alarm request input from the inter-vehicle distance control ECU 4, and the engine ECU 5. Based on the input signal representing the current vehicle speed, the brake actuator 21 and the alarm buzzer 22 are driven and controlled.
[0039]
The brake device (not shown) includes a master cylinder, a wheel cylinder, a pressure increase control valve, a pressure reduction control valve, a reservoir, a brake actuator 21 and the like. Each wheel of the vehicle is provided with a wheel cylinder, and the master cylinder pressure from the master cylinder is sent to each wheel cylinder via each pressure increase control valve. The master cylinder generates a master cylinder pressure by depressing the brake pedal or the brake actuator 21. Also, the hydraulic pressure from each wheel cylinder is sent to the reservoir via each pressure reduction control valve. The brake actuator 21 controls the brake operation by duty-controlling the pressure increase / reduction of the master cylinder pressure corresponding to the atmospheric pressure and the engine negative pressure based on the control of the brake ECU 6.
[0040]
The alarm buzzer 22 is sounded according to a signal indicating an alarm request input from the inter-vehicle distance control ECU 4.
Further, the brake ECU 6 outputs each signal representing the steering angle and the yaw rate to the inter-vehicle distance control ECU 4, and displays a signal representing the brake operating state commanded to the brake actuator 21 via each LAN 7, 9 and the gateway 8. Output to the device 12.
[0041]
Note that members other than the ECUs 4 to 6 in the automatic travel control device 2 are also supplied with power from an in-vehicle battery when an ignition switch is turned on for those requiring power.
Next, details of the operation of the automatic travel control device 2 will be described using the flowcharts shown in FIGS.
[0042]
When the ignition switch and the cruise main switch 23 are turned on and the ECUs 4 to 6 and the forward recognition sensor 3 are activated, the ECUs 4 to 6 and the forward recognition sensor 3 are operated by a computer according to a program stored in advance in a built-in ROM or RAM. The following steps are executed by various arithmetic processes.
[0043]
The program is recorded on a computer-readable recording medium (floppy disk, magneto-optical disk, CD-ROM, hard disk, etc.), and loaded into each ECU 4-6 and the front recognition sensor 3 as necessary. You may make it use by starting.
[0044]
As shown in FIG. 2, first, at step (hereinafter referred to as S) 10000, the inter-vehicle distance control ECU 4 reads the target inter-vehicle time set by the driver using the cruise control switch 13, and the target inter-vehicle time corresponding to the target inter-vehicle distance. Set Td. This target inter-vehicle time corresponds to the set value of the present invention. The target inter-vehicle time is used for setting the target inter-vehicle distance because it is easier for the driver to recognize the time required for the vehicle to travel the distance than to accurately recognize the actual distance. This is because setting the target inter-vehicle distance as the inter-vehicle time is easier to grasp than setting the actual inter-vehicle time, so that the sense of incongruity with the auto cruise control is reduced.
[0045]
Next, in S11000, the front recognition sensor 3 determines a preceding vehicle subject to auto-cruise control based on the curve curvature radius R of the own vehicle input from the inter-vehicle distance control ECU 4, and the preceding vehicle and the own vehicle are determined. The actual inter-vehicle distance D is measured.
Next, in S12000, the front recognition sensor 3 measures the relative speed Vrel between the preceding vehicle and the host vehicle.
[0046]
Next, in S13000, the engine ECU 5 calculates the current vehicle speed Vn based on the signal input from the vehicle speed sensor 14.
Next, in S14000, the inter-vehicle distance control ECU 4 calculates a measured inter-vehicle time Tn (sec) based on the actual inter-vehicle distance D and the current vehicle speed Vn, as shown in Expression (1).
[0047]
Tn = D × 3.6 / Vn (1)
Next, in S15000, the inter-vehicle distance control ECU 4 calculates a target acceleration ATmc. That is, as shown in Expression (2), the inter-vehicle time deviation Tde is obtained based on the target inter-vehicle time Td and the measured inter-vehicle time Tn. The target acceleration ATmc is obtained by referring to a preset target acceleration data map based on the inter-vehicle time deviation Tde and the value Vr-filter obtained by smoothing the relative speed Vrel.
[0048]
Tde = Tn−Td (2)
Next, in S16000, the inter-vehicle distance control ECU 4 calculates the actual acceleration (actual acceleration) ATj of the host vehicle from the time change of the current vehicle speed Vn.
Next, in S17000, the inter-vehicle distance control ECU 4 calculates an acceleration deviation ATdelt based on the target acceleration ATmc and the actual acceleration ATj as shown in Expression (3).
[0049]
ATdelt = ATmc−ATj (3)
Next, in S18000, the engine ECU 5 is based on the target throttle opening degree MA (n−1), the acceleration deviation ATdelt, and the coefficient (gain) G calculated in the routine, as shown in the previous equation (4). Thus, the target throttle opening MA (n) in this routine is calculated.
[0050]
MA (n) = MA (n−1) + G × ATdelta (4)
Then, the engine ECU 5 controls the throttle opening by driving the throttle actuator 16 based on the target throttle opening MA, and adjusts the output of the gasoline engine.
[0051]
When sufficient deceleration cannot be achieved only by the drive control of the throttle actuator 16, the inter-vehicle distance control ECU 4 and the engine ECU 5 first execute a fuel cut deceleration process in S19000, and then perform an overdrive (OD) cut in S20000. Deceleration processing is executed, subsequently, deceleration processing by downshifting is executed in S21000, and finally, deceleration processing by brake is executed in S22000. Here, the braking force on the vehicle increases in the order of deceleration processing by fuel cut → deceleration processing by OD cut → deceleration processing by shift down → deceleration processing by brake. That is, each deceleration process is executed in order of increasing braking force on the vehicle, and deceleration of the vehicle is controlled in stages.
[0052]
In the deceleration process by fuel cut in S19000, the inter-vehicle distance control ECU 4 outputs a signal indicating a fuel cut request to the engine ECU 5 to instruct a fuel cut operation. Then, the engine ECU 5 stops fuel injection from the injector 25 based on a signal indicating a fuel cut request. As a result, the supply of fuel to the engine is prevented and an engine brake is generated, and the own vehicle is decelerated by the engine brake.
[0053]
Further, in the deceleration process by OD cut in S20000, the inter-vehicle distance control ECU 4 outputs a signal indicating an OD cut request to the engine ECU 5 to instruct an OD cut operation. Then, based on the signal indicating the OD cut request, the engine ECU 5 shifts down to the fourth speed when the transmission 17 is shifted to the fifth speed (that is, the overdrive shift position). As a result, a large engine brake is generated by downshifting from the fifth speed to the fourth speed, and the host vehicle is decelerated by the engine brake.
[0054]
Further, in the deceleration process by the downshift in S21000, the inter-vehicle distance control ECU 4 outputs a signal indicating a downshift request to the engine ECU 5 to instruct a downshift operation. Then, the engine ECU 5 shifts down to the third speed when the transmission 17 is shifted to the fourth speed based on the signal indicating the downshift request. As a result, a large engine brake is generated by the downshift from the fourth speed to the third speed, and the own vehicle is decelerated by the engine brake.
[0055]
In S22000, the inter-vehicle distance control ECU 4 and the brake ECU 6 execute a deceleration process using a brake. FIG. 3 shows details of the processing in S22000.
First, in S22010, the inter-vehicle distance control ECU 4 sets the determination values ATref4 to ATref6, ATmcref4, and ATmcref5 used in the following steps.
[0056]
Each of the determination values ATref5 to ATref6 is a negative value, and the determination value ATref4 is a positive value. Further, since the determination value ATref5 has already exhibited the deceleration effect due to the downshift, the value is larger than the determination value ATref6 (ATref6 <ATref5), thereby preventing the brake from becoming difficult to operate.
[0057]
Each determination value ATmcref4 is a negative value, the determination value ATmcref5 is a negative value or a value near 0, and the determination value ATmcref4 is smaller than the determination value ATmcref5 (ATmcref4 <ATmcref5 <0 (≈0). )).
[0058]
Next, in S22020, the inter-vehicle distance control ECU 4 inputs the actual throttle opening detected by the throttle opening sensor 24 via the engine ECU 5, and determines whether or not the actual throttle opening is fully closed (= 0 °). judge. If the actual throttle opening is fully closed (S22020: YES), the process proceeds to S22030. If the actual throttle opening is not fully closed (S22020: NO), the process proceeds to S22040.
[0059]
In S22030, the inter-vehicle distance control ECU 4 determines whether or not the signal representing the control state of the shift position of the transmission 17 input from the engine ECU 5 corresponds to the third speed. When the shift position of the transmission 17 is the third speed (S22030: YES), the process proceeds to S22050, and when it is not the third speed (S22030: NO), the process proceeds to S22060.
[0060]
In S22050, the inter-vehicle distance control ECU 4 determines the magnitude of the acceleration deviation ATdelt and the determination value ATref5. If the acceleration deviation ATdelt is smaller than the determination value ATref5 (ATdelt <ATref5, S22050: YES), the process proceeds to S22070. If the acceleration deviation ATdelt is greater than or equal to the determination value ATref5 (ATdel ≧ ATref5, S22050: NO), the process proceeds to S2080. To do.
[0061]
In S22060, the inter-vehicle distance control ECU 4 determines the magnitude of the acceleration deviation ATdelt and the determination value ATref6. If the acceleration deviation ATdelt is smaller than the determination value ATref6 (ATdelt <ATref6, S22060: YES), the process proceeds to S22070. If the acceleration deviation ATdelt is equal to or larger than the determination value ATref6 (ATdel ≧ ATref6, S22060: NO), the process proceeds to the main routine. Return and return to S10000.
[0062]
In S22070, the inter-vehicle distance control ECU 4 outputs a signal indicating a brake request to the brake ECU 6 to instruct a brake operation. Then, the process returns to the main routine and returns to S10000.
In S2080, the inter-vehicle distance control ECU 4 determines the magnitude of the target acceleration ATmc and the determination value ATmcref4. If the target acceleration ATmc is larger than the determination value ATmcref4 (ATmc> ATmcref4, S2080: YES), the process proceeds to S22090. If the target acceleration ATmc is equal to or less than the determination value ATmcref4 (ATmc ≦ ATmcref4, S2080: NO), the process proceeds to the main routine. Return and return to S10000.
[0063]
In S22090, the inter-vehicle distance control ECU 4 determines the magnitude of the acceleration deviation ATdelt and the determination value ATref4. If the acceleration deviation ATdelt is larger than the determination value ATref4 (ATdel> ATref4, S22090: YES), the process proceeds to S22040. If the acceleration deviation ATdelt is equal to or smaller than the determination value ATref4 (ATdel ≦ ATref4, S22090: NO), the process proceeds to S22100. To do.
[0064]
In S22100, the inter-vehicle distance control ECU 4 determines whether the target acceleration ATmc and the determination value ATmcref5 are large or small. When the target acceleration ATmc is larger than the determination value ATmcref5 (ATmc> ATmcref5, S22100: YES), the process proceeds to S22040. When the target acceleration ATmc is equal to or less than the determination value ATmcref5 (ATmc ≦ ATmcref5, S22100: NO), the process proceeds to the main routine. Return and return to S10000.
[0065]
In S22040, the inter-vehicle distance control ECU 4 stops outputting the signal indicating the brake request and issues a brake operation release instruction. Then, the process returns to the main routine and returns to S10000.
When a signal indicating a brake request is output from the inter-vehicle distance control ECU 4 and a brake operation instruction is issued, the brake ECU 6 controls the brake actuator 21 based on the signal to execute the brake operation. As a result, the host vehicle is decelerated by the brake operation controlled by the brake actuator 21.
[0066]
FIG. 4 is a block diagram of a control system for brake operation by the brake ECU 6.
The actual acceleration ATj is calculated by pseudo-differentiating the current vehicle speed Vn. An acceleration term ATdelt, which is a deviation between the actual acceleration ATj and the target acceleration ATmc, is integrated to calculate an integral term. In addition, a master data corresponding to the acceleration deviation ATdelt is obtained by referring to a predetermined data map. Then, the integral term and the master cylinder pressure are added to calculate a target master cylinder pressure (hereinafter referred to as a target master cylinder pressure).
[0067]
A pressure deviation between the target master cylinder pressure and an actual master cylinder pressure detected by the master cylinder pressure sensor 18 (hereinafter referred to as an actual master cylinder pressure) is calculated. The proportional term and derivative term of the pressure deviation are added, and the added value is passed through a bandpass filter to remove noise, whereby the pressure increase / decrease command value of the brake actuator 21 is obtained.
[0068]
The brake actuator 21 controls the brake operation of the vehicle by duty-controlling the pressure increase / reduction of the master cylinder pressure corresponding to the atmospheric pressure and the engine negative pressure based on the pressure increase / decrease command value. The actual acceleration ATdelt is calculated from the current vehicle speed Vn decreased by the brake operation and fed back to the input side of the control system.
[0069]
As described above, in the automatic travel control device 2, acceleration and deceleration are continuously controlled by continuously controlling the throttle opening and the master cylinder pressure according to the increase and decrease of the acceleration deviation ATdelt. Here, considering the safety of the automatic travel control device 2, it is desirable to define the upper and lower limits of acceleration / deceleration.
[0070]
Therefore, when the target acceleration ATmc is obtained in S15000, the upper limit value of the target acceleration ATmc is specified to 0.7 m / s2, for example, and the lower limit value is specified to -2.45 m / s2, for example. By thus defining the upper limit value and the lower limit value of the target acceleration ATmc, it is possible to prevent sudden behavior fluctuations. As a method for defining the lower limit value of acceleration / deceleration, in the block diagram shown in FIG. 4, the upper limit value of the target master cylinder pressure corresponds to the lower limit value of the target acceleration ATmc (for example, −2.45 m / s 2). You may use the method prescribed | regulated to the value to do. By the way, the upper and lower limits of the acceleration / deceleration may be determined experimentally.
[0071]
Next, the details of the control operation of the display 31 that displays the operation state of the automatic travel control device 2 will be described.
FIG. 5 is a schematic diagram for explaining a display example of the display 31.
The display 31 is configured by a known level indicator in which a plurality of horizontally long LEDs are arranged in the vertical direction. And LED31U arrange | positioned at the uppermost part of the indicator 31 and LED31L arrange | positioned at the lowermost part of the indicator 31 are formed larger than other LED, and can blink-display. A reference line SL indicating the target acceleration ATmc = 0 m / s 2 is displayed at a predetermined position between the LEDs. With this reference line SL as a boundary line, an LED arranged above the reference line SL displays a positive value of the target acceleration ATmc, and an LED arranged below the reference line SL is a minus side of the target acceleration ATmc. Displays the value of.
[0072]
The display 31 is controlled after the target acceleration ATmc is obtained in S15000. When the obtained target acceleration ATmc takes a positive value (that is, when acceleration is required), as shown in FIG. 5B, the LED arranged above the reference line SL becomes the target acceleration ATmc. The corresponding number lights up. Further, when the target acceleration ATmc takes a negative value (that is, when deceleration is required), as shown in FIG. 5C, the LED arranged below the reference line SL is replaced with the target acceleration ATmc. Only the number corresponding to is lit. Then, when the target acceleration ATmc takes the prescribed lower limit value, the LED 31L disposed at the lowermost part of the display 31 blinks as shown in FIG. Similarly, when the target acceleration ATmc takes the prescribed upper limit value, the LED 31U arranged at the top of the display 31 blinks (not shown).
[0073]
As described above, in the present embodiment, the display 31 indicates how close the target acceleration ATmc set by the automatic travel control device 2 is to the specified upper limit value or lower limit value. It is possible to reliably notify the driver whether the acceleration / deceleration capability of the traveling control device 2 has reached the upper limit or the lower limit. Therefore, the driver determines how much the automatic traveling control device 2 can further accelerate / decelerate according to the lighting state of the LED, and the automatic traveling control device 2 accelerates / decelerates according to blinking of each LED 31U, 31L. This makes it possible to grasp that acceleration / deceleration cannot be performed. That is, the driver can accurately grasp the acceleration / deceleration capability of the automatic travel control device 2 based on the display on the display 31. Based on the acceleration / deceleration capability, the driver can manually operate (brake operation or throttle). The necessity of operation) can be judged by itself.
[0074]
In other words, the driver's decision to accelerate or decelerate the vehicle depends on many factors surrounding the vehicle (for example, external environment such as road gradient and weather, physical condition, vehicle type, distance between the preceding vehicle and the following vehicle). Influenced by distance, speed of own vehicle, etc. Accordingly, it is desirable that the driver himself can determine the transition timing from the automatic travel control by the automatic travel control device 2 to the manual operation (brake operation or throttle operation) by the driver. According to the present embodiment, since the driver can grasp whether the acceleration / deceleration capability of the automatic travel control device 2 has reached the limit value, the transition timing from the automatic travel control by the automatic travel control device 2 to the manual operation is determined. Judgment becomes easy. Therefore, even in the case of (1) to (3), the driver does not feel uneasy about the operation of the automatic travel control device 2, and the discomfort associated with the travel control of the automatic travel control device 2 is wiped away. Can do.
[0075]
In addition, this invention is not limited to the said embodiment, You may change as follows, and even in that case, the effect | action and effect similar to or more than the said embodiment can be acquired.
(1) In the above-described embodiment, the target acceleration ATmc is used as an example of the “control target value”, and the target acceleration ATmc is displayed on the display 31. In addition to this, a control system for obtaining desired acceleration / deceleration For example, a target brake pressure, a target throttle opening, a target torque, or the like may be adopted as a control target value for the control system (the brake operation control system or the throttle operation control system shown in FIG. 4) and displayed. Then, instead of the control target value, an operation amount corresponding to the control target value in the control system, that is, an actual brake pressure, a target throttle opening, a target torque, etc. may be adopted and displayed. Furthermore, you may make it display the actual acceleration ATj output as a result of those control target values on the indicator 31. FIG.
[0076]
Here, if the actual acceleration ATj is displayed on the display 31, the control limit of the automatic travel control device 2 can be displayed more directly without being affected by the response delay of the control system from the control target value. it can. For example, the display shown in FIG. 5D shows a state where the actual acceleration ATj is less than or equal to the lower limit value of the target acceleration ATmc. Since the target acceleration ATmc is controlled at least by the lower limit value, the acceleration deviation ATdelt obtained in S17000 always takes a positive value, and the control system that is continuously controlled in accordance with the acceleration deviation ATdelt that takes this positive value is The vehicle behavior state at that time always tries to be controlled to the acceleration side. Therefore, when the display shown in FIG. 5 (d) is obtained, the vehicle speed control device 2 cannot decelerate more than the deceleration at that time unless there is a large change in the running resistance. It is possible to easily determine the necessity of own brake operation from the distance.
[0077]
(2) FIG. 6 is a flowchart showing the control operation of the display 31 in another embodiment embodying the present invention.
The display 31 is controlled after the target acceleration ATmc is obtained in S15000 and the actual acceleration ATj is obtained in S16000.
[0078]
First, in S15510, an LED corresponding to the obtained target acceleration ATmc is turned on (see FIGS. 5B and 5C). Next, in S15520, it is determined whether or not the obtained actual acceleration ATj is equal to or greater than the upper limit value of the specified target acceleration ATmc. If the actual acceleration ATj is equal to or greater than the upper limit value (S15520: YES), the process proceeds to S15540 and is less than the upper limit value. In the case of (S15520: NO), the process proceeds to S15530.
[0079]
In S15540, after the LED 31U arranged at the top of the display 31 blinks, the process returns to S15510.
In S15530, it is determined whether or not the obtained actual acceleration ATj is less than or equal to the lower limit value of the specified target acceleration ATmc. If it is less than or equal to the addition / subtraction value (S15530: YES), the process proceeds to S15550 and exceeds the addition / subtraction value. If (S15530: NO), the process returns to S15510.
[0080]
In S15550, after the LED 31L arranged at the bottom of the display 31 blinks (see FIG. 5D), the process returns to S15510.
As described above, the target acceleration ATmc is displayed using the display 31, and when the actual acceleration ATj exceeds the control limit value, the LEDs 31U and 31L are blinked, thereby further improving the effect of the above embodiment. it can.
[0081]
(3) The indicator 31 is not necessarily provided on the instrument panel, and may be provided anywhere in the vehicle as long as the driver can see it.
(4) In the above-described embodiment, the notification is made visually using the display 31. However, the notification may be made audibly by issuing a notification sound or a voice message. Also, visual notification and auditory notification may be used together. For example, auditory notification is not always performed, but when the LEDs 31U and 31L are in a blinking state (automatic travel control device 2). Auditory notification may be performed only when the acceleration / deceleration capacity reaches the upper limit or the lower limit.
[0082]
(5) In the above embodiment, the upper and lower limit values of the target acceleration ATmc are, for example, 0.7 m / s.², -2.45 m / s²Stipulated. This is a “soft” point of view from a fail-safe point of view, such as preventing sudden fluctuations in behavior, even if the physical (hardware) capability can be more than that. It is determined. On the other hand, there may be a case where the limit value is physically determined from a “hard” viewpoint, for example, from the traveling aspect of the vehicle including the traveling resistance and the engine speed. For example, if a situation such as a steep downhill is assumed, it is easy to understand, but in this case, the above-mentioned software-defined -2.45 m / s²It is conceivable that this value is not physically realized. Therefore, in this case, as a hardware lower limit value, for example, -1.5 m / s.²Such a value will be determined. Of course, this value varies depending on the situation and, of course, may be larger than a value determined from a soft viewpoint. Therefore, when the upper and lower limit values determined from these two viewpoints are included and determination can be made based on both values, it is preferable to notify when either value is reached.
[0083]
(6) In the above embodiment, it is notified how close the acceleration / deceleration capability of the automatic travel control device 2 is to the upper limit or the lower limit. However, the present invention is not limited to this. In the case of execution, the information on which deceleration means is being executed may be provided.
[0084]
That is, in the above embodiment, the braking force increases in the order of deceleration processing by fuel cut (S19000) → deceleration processing by OD cut (S20000) → deceleration processing by shift down (S21000) → deceleration processing by brake (S22000). Each deceleration process (deceleration means) is executed in this order. Therefore, what deceleration processing (deceleration means) is currently performed may be notified using at least one of the visual notification method and the auditory notification method.
[0085]
In this way, the driver can determine how much the automatic travel control device 2 can further decelerate according to the deceleration process (deceleration means) currently being executed. Since it can be judged by itself, the same operation and effect as the above-mentioned embodiment can be obtained.
[0086]
Further, when the deceleration process (deceleration means) to be executed last is being executed, the driver may be notified of this.
In other words, in the above-described embodiment, the brake deceleration process (S22000) is executed last. Therefore, at the time when the brake deceleration process is executed, at least one of the visual notification method and the auditory notification method is performed. What is necessary is just to alert | report.
[0087]
In this way, the driver can grasp that the automatic travel control device 2 cannot decelerate more than the deceleration at that time. Therefore, in the above embodiment, the same action as when the LEDs 31U and 31L blink. An effect can be obtained.
(7) In addition to each deceleration process (deceleration process by fuel cut, deceleration process by overdrive cut, deceleration process by shift down, deceleration process by brake) of the above embodiment, various decelerations to obtain a required deceleration 1 processing (deceleration processing by retarding the ignition timing to delay the ignition timing of the engine, deceleration processing by bringing the torque converter into the lock-up state, deceleration processing by exhaust brake and retarder that increases the flow resistance of exhaust from the engine, etc.) One or a combination of any two or more may be implemented.
[0088]
Also in this case, it is desirable to execute the deceleration processes in the order of increasing braking force. Then, similarly to the above (5), it may be notified which deceleration process (deceleration means) is being executed at the present time. You may make it alert | report to.
[0089]
(8) In the deceleration process by downshifting (S21000), when the transmission 17 has been shifted to the fourth speed, the transmission is shifted down to the second speed or the first speed. As a result, a very large engine brake is generated by the downshift from the fourth speed to the second speed or the first speed, and the own vehicle is decelerated by the engine brake.
[0090]
That is, in the deceleration process by downshifting, the number of shift stages to be shifted down is not limited to the first speed, and may be shifted down by two or more speeds. Based on this, an optimal value may be set.
[0091]
(9) In the deceleration process by OD cut (S20000), if the transmission 17 has been shifted to the fifth speed (that is, the overdrive shift position), it is shifted down to the third speed. As a result, a very large engine brake is generated by shifting down from the fifth speed to the third speed, and the own vehicle is decelerated by the engine brake.
[0092]
In other words, in the deceleration process using OD cut, the number of shift stages to be shifted down is not limited to the first speed, and may be shifted down by two or more speeds. Based on this, an optimal value may be set.
[0093]
(10) In the above embodiment, the master cylinder pressure is considered as the brake pressure, but the wheel cylinder pressure of the brake device may be adopted as the brake pressure.
(11) In the above-described embodiment, the measurement inter-vehicle time Tn is maintained at the target inter-vehicle time. However, the present invention is not limited to this. For example, the measurement inter-vehicle distance may be maintained at the target inter-vehicle distance.
[0094]
  InvoiceIn termsAre expressed as “value corresponding to the actual inter-vehicle distance” and “value corresponding to the target inter-vehicle distance”, but this is not the inter-vehicle distance itself but, for example, time is used as a physical quantity corresponding to the inter-vehicle distance. However, it is also possible to use the value obtained by dividing the inter-vehicle distance by the vehicle speed (inter-vehicle time) as another physical quantity. expressing.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an embodiment embodying the present invention.
FIG. 2 is a flowchart for explaining the operation of the embodiment;
FIG. 3 is a flowchart for explaining details of processing in S22000 of FIG. 2;
FIG. 4 is a block diagram of a control system for brake operation in one embodiment.
FIG. 5 is a schematic diagram for explaining a display example of a display according to an embodiment.
FIG. 6 is a flowchart for explaining the operation of another embodiment;
[Explanation of symbols]
3 ... Front recognition sensor 4 ... Inter-vehicle distance control ECU 5 ... Engine ECU
6 ... Brake ECU 16 ... Throttle actuator
17 ... Transmission 21 ... Brake actuator
24 ... Throttle opening sensor 25 ... Injector 31 ... Indicator

Claims (1)

In an automatic travel control device that detects a value corresponding to an actual inter-vehicle distance between the own vehicle and a preceding vehicle and accelerates or decelerates the own vehicle so that a value corresponding to the actual inter-vehicle distance becomes a value corresponding to a target inter-vehicle distance. ,
Control means for obtaining a control target value for accelerating / decelerating the vehicle;
The driver is notified of at least one of the control target value obtained by the control means, the operation amount corresponding to the control target value, or the actual acceleration of the host vehicle controlled based on the control target value. An automatic travel control device comprising an informing means for performing the operation.

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