JP2013203341A - Travel control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain transient characteristics and a vehicular gap matching sensitivity of a driver even if a plurality of modes can be selected as a traveling mode and output characteristics corresponding to a traveling mode selected in vehicular gap control are set.SOLUTION: A sensitivity correction coefficient calculation section 32 sets sensitivity correction coefficients Ka, Kc, Kd by reading an acceleration adjusting signal, a deceleration adjusting signal and a preceding vehicular gap signal which are set by a driver operating a mode characteristic adjusting switch 22. Each of the sensitivity correction coefficients Ka, Kc, Kd is read by a control target vehicle velocity calculation section 35. The control target vehicle velocity calculation section 35 sets new characteristics by correcting the characteristics which are set for each of engine modes M1-M3 set by the driver operating a mode selecting switch 18, with each of the sensitivity correction coefficients Ka, Kc, Kd.

Description

  The present invention relates to a travel control device that can adjust a transient characteristic set for each of a plurality of travel modes having different output characteristics in accordance with a driver's preference.

  2. Description of the Related Art Conventionally, there is known a vehicle driving support device that recognizes a vehicle exterior environment in front of the host vehicle using a forward recognition device such as a stereo camera, and performs traveling control of the host vehicle based on the recognized vehicle exterior environment. One of the vehicle driving support devices includes a constant speed traveling control that travels at the vehicle speed (set vehicle speed) set by the driver according to the recognition result of the preceding vehicle, and a following traveling control that travels following the preceding vehicle. There is an inter-vehicle distance control (ACC; Adaptive Cruise Control) system.

  This ACC system checks whether there is a preceding vehicle in the traveling area of the own vehicle traveling path based on information from the forward recognition device, and if the preceding vehicle is recognized, the preceding vehicle is registered and registered. Follow-up driving control is performed to make the vehicle follow the vehicle in a state where the relative distance and the relative speed are kept constant by throttle control and brake control. On the other hand, if the preceding vehicle is not detected, the driver sets The constant speed traveling control for traveling at the set vehicle speed is executed.

  On the other hand, as a technique related to power train control of an engine or an automatic transmission, recently, a plurality of driving modes are provided, and a technique for setting engine output characteristics or automatic transmission shifting characteristics according to a driving mode selected by a driver. It has been known.

  For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2008-120302), a plurality of preset driving modes are applied to the ACC system, and the ACC control corresponding to the driving mode selected by the driver is executed in the ACC system. Techniques to do this are disclosed.

  That is, in this document, three modes are set as a driving mode: a normal mode suitable for normal driving, a save mode in which the output torque of the engine is suppressed, and a power mode in which excellent output characteristics are exhibited. In the ACC control, an upper limit guard value at the time of acceleration or deceleration corresponding to the driving mode selected by the driver is set. As a result, in the ACC control, when the save mode is selected as the travel mode, the distance from the preceding vehicle is controlled with a gentle acceleration or deceleration characteristic compared to the normal mode, and the power mode Is selected, the distance from the preceding vehicle is controlled to be constant by relatively rapid acceleration or deceleration as compared with the normal mode.

JP 2008-120302 A

  However, in the technique disclosed in the above-described document, the acceleration characteristic or the deceleration characteristic at the time of ACC control is uniformly controlled in accordance with the driving mode selected by the driver, so that it follows the driving feeling of the driver. There may not be. For example, when starting from a stopped state following a preceding vehicle, if the save mode is selected as the travel mode, the start is slow and the distance from the preceding vehicle gradually increases, so some drivers may feel slow. You may remember. On the contrary, when the power mode is selected as the traveling mode, the start is agile, so that a driver may feel a sudden acceleration.

  Similarly, in the deceleration running in the ACC control, when the save mode is selected as the running mode, the deceleration becomes slow and the distance from the preceding vehicle is narrowed. You may remember. On the other hand, when the power mode is selected as the travel mode, the speed is abruptly decelerated, and there may be a feeling of jerkyness due to sudden deceleration.

  In view of the above circumstances, the present invention is able to select a plurality of modes as the travel mode, and even if the output characteristics corresponding to the travel mode selected in the inter-vehicle distance control are preset, the sensitivity of the driver An object of the present invention is to provide a travel control device capable of setting a transient characteristic that meets the requirements.

  A travel control device according to the present invention includes a preceding vehicle detection unit that detects a preceding vehicle that travels ahead of the host vehicle, a driving state detection unit that detects a driving state of the host vehicle, and a plurality of driving modes having different output characteristics. From the driving mode selection means for selecting one driving mode by an external operation, and the inter-vehicle distance between the host vehicle and the preceding vehicle according to the output characteristics corresponding to the one driving mode selected by the driving mode selection means. A travel control device comprising travel control means for following the vehicle so as to converge to a preset target inter-vehicle distance, a characteristic adjustment for setting a transient correction value for adjusting a transient characteristic set for each of the travel modes by an external operation And a new transient characteristic by correcting the transient characteristic set for each of the travel modes with the transient correction value. Set to.

  According to the present invention, since the driver can adjust the transient characteristics set for each driving mode by an external operation, a plurality of modes can be selected as the driving mode, and the driving mode selected in the inter-vehicle distance control can be selected. Even when the output characteristics corresponding to the above are set in advance, it is possible to set a transient characteristic that matches the sensitivity of the driver.

Schematic configuration diagram of a vehicle equipped with a travel control device Configuration diagram of the travel control device Functional block diagram of the inter-vehicle distance control device (A) is a characteristic diagram of a normal mode map, (b) is a characteristic diagram of a save mode map, and (c) is a characteristic diagram of a power mode map. Conceptual diagram of sensitivity correction coefficient table (A) is explanatory drawing of the state in which the preceding inter-vehicle distance is separated from the target inter-vehicle distance in ACC control, and (b) is an explanatory diagram of the state in which the preceding inter-vehicle distance is shorter than the target inter-vehicle distance in ACC control. Illustration of the distance deviation map Explanatory drawing showing the relationship between the following target vehicle speed and the acceleration guard value corresponding to each engine mode Explanatory drawing of each guard value set in follow-up running and constant speed running during ACC control

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 in FIG. 1 denotes a vehicle (host vehicle) such as an automobile. An engine 2 is mounted on the vehicle 1, and an automatic transmission 3 is connected to the output side of the engine 2. The engine 2 is provided with an electronically controlled throttle valve 4 in the intake system, and a throttle actuator 4 a is connected to the throttle valve 4. An injector 4b for injecting a predetermined amount of fuel into the combustion chamber of each cylinder is disposed.

  On the other hand, reference numeral 5 denotes an in-vehicle camera as a preceding vehicle detection means. The in-vehicle camera 5 is a stereo camera having a main camera 5a and a sub camera 5b, and each camera 5a, 5b has an image sensor such as a CCD or a CMOS. Is provided. Each of the cameras 5a and 5b is disposed at both sides of the upper part of the windshield and sandwiching a room mirror (not shown) so that the traveling environment in front of the host vehicle 1 can be photographed.

  Image data captured by the in-vehicle camera 5 is transmitted to an image processing unit (IPU) 6. The IPU 6 generates a distance image by obtaining distance information from a corresponding positional shift amount (parallax) with respect to an image ahead of the host vehicle 1 taken by the pair of left and right cameras 5a and 5b. Then, based on the distance image data, the driving environment in front of the host vehicle 1 is recognized, and the following vehicle (hereinafter referred to as “preceding vehicle”) that travels in front of the host vehicle 1 is detected. When the preceding vehicle is detected by the IPU 6, the relative inter-vehicle distance (the preceding inter-vehicle distance) between the host vehicle 1 and the preceding vehicle and the vehicle speed (the preceding vehicle speed) of the preceding vehicle are obtained. The preceding vehicle information such as the preceding inter-vehicle distance L and the preceding vehicle speed obtained by the IPU 6 is read by the inter-vehicle distance control device (ACC_ECU) 7 as the travel control means. The function of the ACC_ECU 7 will be described later.

  The vehicle 1 is equipped with an engine control device (E / G_ECU) 8, a transmission control device (T / M_ECU) 9, and the like as a control device in addition to the ACC_ECU 7 described above. The ECUs 7 to 9 are connected to each other through an in-vehicle communication line 11 such as CAN (Controller Area Network) communication so that they can communicate with each other. Further, each of the ECUs 7 to 9 is mainly composed of a microcomputer, and has a well-known CPU, ROM, RAM, and nonvolatile storage means such as an EEPROM. The CPU is a control stored in the ROM. According to the program, the detection signals from the sensors and switches as the driving state detection means for detecting the driving state of the host vehicle 1 are processed, and various data stored in the RAM and various types of data stored in the nonvolatile memory are processed. Predetermined control is executed based on the learning value data and the like.

  The E / G_ECU 8 controls the operating state of the engine 2, and as shown in FIG. 2, an engine speed sensor 12 for detecting the engine speed on the input side, an intake air quantity sensor 13 for detecting the intake air quantity, Sensors that detect vehicle and engine operating conditions, such as an accelerator opening sensor 14 that detects the accelerator opening from the amount of depression of an accelerator pedal (not shown), a throttle opening sensor 15 that detects the opening of the throttle valve 4, and the like. Is connected. Further, an ACC control operation switch (hereinafter referred to as a “cruise control switch”) 17 is connected to the input side of the E / G_ECU 8.

  The cruise control switch 17 includes an inter-vehicle distance setting switch, a CRUISE switch, a RES (resume) / ACC (accelerate) switch, a SET / COAST switch, and a CANCEL switch. Here, the function of each switch will be briefly described.

  The inter-vehicle distance setting switch is a switch for setting an inter-vehicle correction value for the driver to correct the target inter-vehicle distance Lo with the preceding vehicle at the time of ACC control to a desired value. “Long”, “Medium”, “Short” Etc., can be set in stages. The CRUISE switch is used to turn on / off the ACC control. When the switch is turned on, the system enters a standby state. When the RES / ACC switch is turned on, the previous set vehicle speed (the vehicle speed set during ACC control, that is, the upper limit value of the target vehicle speed) is set as the current set vehicle speed. When the RES / ACC switch is turned on, the set vehicle speed increases stepwise. Is done. On the other hand, the SET / COAST switch is a switch for starting ACC control. When turned on, ACC control is started, and when further turned on, the set vehicle speed is gradually reduced. The CANCEL switch is a switch for canceling the ACC control.

  Further, an actuator for controlling engine driving, such as a throttle actuator 4a for opening / closing the throttle valve 4 and an injector 4b provided for each cylinder, is connected to the output side of the E / G_ECU 8.

  The E / G_ECU 8 sets the fuel injection timing and the fuel injection pulse width (pulse time) for the injector 4b based on the input detection signals from the sensors. Further, a throttle opening signal is output to 4a for driving the throttle valve 4 to control the opening of the throttle valve 4. Further, when the SET / COAST switch of the cruise control switch 17 is turned on and ACC control is started, a target throttle opening degree θth calculated by an ACC_ECU 7 described later is read, and the throttle valve 4 is opened to the electronic control throttle device. The feedback control is performed so that the degree converges to the target throttle opening θtho.

  By the way, the non-volatile storage means provided in the E / G_ECU 8 stores mode maps Mp1, Mp2, and Mp3 corresponding to the engine modes (normal mode M1, save mode M2, and power mode M3) as travel modes. ing. As shown in FIGS. 4A to 4C, each of the mode maps Mp1, Mp2, and Mp3 is a three-dimensional map that stores the target torque at each lattice point with the accelerator opening and the engine speed as the lattice axes. It is configured.

  Each of the modes M1 to M3 is operated when the driver externally operates a mode selection switch 18 serving as a travel mode selection means disposed on a steering handle (not shown) or the like. Selected. This mode selection switch 18 is a triple switch, and the driver can select an engine mode (normal mode M1, save mode M2, power mode M3) having different engine output characteristics by turning on an arbitrary switch. it can. When the normal mode M1 is selected by the mode selection switch 18, the normal mode map Mp1 is selected, when the save mode M2 is selected, the save mode map Mp2 is selected, and when the power mode M3 is selected. The power mode map Mp3 is selected.

  Hereinafter, engine output characteristics of the modes M1 to M3 set in the mode maps Mp1 to Mp3 will be described. The normal mode map Mp1 shown in FIG. 4 (a) is set to a characteristic in which the target torque changes linearly in a region where the accelerator opening is relatively small, and the maximum target torque is obtained when the opening of the throttle valve 4 is near fully open. It is set to become.

  In addition, the save mode map Mp2 shown in FIG. 5B has a lower target torque than the normal mode map Mp1 described above, and the output torque is suppressed even when the accelerator pedal is fully depressed. By doing so, you can enjoy accelerator work such as depressing the accelerator pedal. Furthermore, since the increase in the target torque is suppressed, both easy drive performance and low fuel consumption can be achieved in a balanced manner. For example, even a vehicle equipped with a 3-liter engine 2 has a smooth output characteristic while ensuring sufficient output equivalent to a 2-liter engine, and a target torque that emphasizes ease of handling in practical areas such as in the city is set. The

  Further, in the power mode map Mp3 shown in FIG. 5C, the rate of change of the target torque with respect to the change of the accelerator opening is set to be large in almost the entire operation region.

  Thus, according to the present embodiment, when the driver operates the mode selection switch 18 to select any engine mode (normal mode M1, save mode M2, or power mode M3), the corresponding mode is selected. The map Mp1, Mp2, or Mp3 is selected, and the target torque is set based on the mode map Mp1, Mp2, or Mp3. Therefore, three different types of accelerator responses can be enjoyed with one vehicle. The opening / closing speed of the throttle valve 4 is set so as to operate gently in the save mode map Mp2 and quickly in the power mode map Mp3. Therefore, the acceleration / deceleration, which is a transient characteristic, is also different in each mode M1 to M3.

  The T / M_ECU 9 performs shift control of the automatic transmission 3, and includes a vehicle speed sensor 19 for detecting the vehicle speed on the input side, an inhibitor switch 20 for detecting a range where a select lever (not shown) is set, and the like. And a control valve 21 for controlling the shift of the automatic transmission 3 is connected to the output side. The T / M_ECU 9 determines the set range of the select lever based on the signal from the inhibitor switch 20, and when it is set to the D range, the gear shift according to the shift pattern specified based on the vehicle speed and the accelerator opening. A signal is output to the control valve 21 to perform shift control. This shift pattern is variably set corresponding to the engine mode (normal mode M1, save mode M2, or power mode M3) set by the E / G_ECU 8.

  In addition to the IPU 6 and the mode selection switch 18 described above, the ACC_ECU 7 is connected to a mode characteristic adjustment switch 22 as characteristic adjustment means. A brake booster 16 is connected to the output side.

  The mode characteristic adjustment switch 22 has an acceleration adjustment function for adjusting a transient characteristic (following acceleration / deceleration characteristic) set in the engine mode (normal mode M1, save mode M2, or power mode M3) selected during ACC control. The vehicle has a transient characteristic adjustment function including a deceleration adjustment function and a preceding inter-vehicle adjustment function for adjusting a target inter-vehicle distance (“long”, “medium”, “short”) Lo set by operating the cruise control switch 17.

  The mode characteristic adjustment switch 22 is, for example, a switching type dial switch. After selecting one of the acceleration adjustment function, the deceleration adjustment function, and the inter-vehicle distance adjustment function, by operating the dial, for example, Even when the save mode M2 is selected as the engine mode, the preceding vehicle can be caused to follow by agile acceleration or deceleration, or the target inter-vehicle distance Lo can be finely adjusted according to the user's preference. Similarly, even when the power mode M3 is selected, the preceding vehicle can be caused to follow by slow acceleration or deceleration, and the target inter-vehicle distance Lo can be finely adjusted according to the user's preference. Can do.

  That is, when the SET / COAST switch provided in the cruise control switch 17 is turned on and the ACC control is started, the ACC_ECU 7 reads the preceding vehicle information such as the preceding vehicle speed and the preceding inter-vehicle distance L obtained by the IPU 6, When the vehicle is not captured, the set vehicle speed is set as the target vehicle speed. On the other hand, when the preceding vehicle is captured and the preceding vehicle speed is lower than the set vehicle speed, the preceding inter-vehicle distance L is set to the target inter-vehicle distance Lo. The set vehicle speed is maintained until the target vehicle speed is reached, and when the target inter-vehicle distance Lo is reached, the target vehicle speed is obtained from the difference between the preceding vehicle speed and the own vehicle speed. Then, a target throttle opening corresponding to the target vehicle speed is obtained and output to the E / G_ECU 8. Therefore, when the current host vehicle speed is lower than the target vehicle speed, the throttle valve 4 is opened for acceleration operation. On the other hand, when the current vehicle speed is higher than the target vehicle speed, the throttle valve 4 is closed for deceleration operation.

  Even if the throttle valve 4 is closed and decelerated, if the preceding inter-vehicle distance L is shorter than the target inter-vehicle distance Lo, the brake booster 16 is operated. The brake booster 16 forcibly supplies the brake hydraulic pressure to the brake wheel cylinders 16 a provided for the four wheels, and the brake hydraulic pressure is supplied to each brake wheel cylinder 16 a via the brake booster 16. Each wheel is braked, and the running vehicle 1 is forcibly decelerated.

  Here, the ACC control processed by the ACC_ECU 7 will be described in more detail using the functional block diagram shown in FIG.

  As shown in the figure, the ACC_ECU 7 includes a target vehicle speed calculation unit 31, a sensitivity correction coefficient calculation unit 32, a tracking target vehicle speed calculation unit 33, a tracking flag calculation unit 34, and a control target vehicle speed calculation as functions for executing ACC control. Unit 35, ACC control required horsepower (hereinafter referred to as "ACC required horsepower") calculating unit 36, ACC control required torque (hereinafter referred to as "ACC required torque") calculating unit 37, accelerator required torque calculating unit 38, required torque selection A calculation unit 39, a target throttle opening calculation unit 40, a pseudo accelerator opening calculation unit 41, and a required braking force calculation unit 42 are provided.

  Next, the ACC control process executed by each calculation unit 31 to 42 will be described. When the driver turns on the SET / COAST switch of the cruise control switch 17 while the vehicle is traveling, the ACC control is started, and the target vehicle speed calculation unit 31 sets the target vehicle speed Sst [Km / h] set by the cruise control switch 17 as a target. Set as vehicle speed St [Km / h].

  The sensitivity correction coefficient calculation unit 32 includes an acceleration adjustment signal, a deceleration adjustment signal output according to an acceleration adjustment function, a deceleration adjustment function, and an inter-vehicle distance adjustment function selected by the driver operating the mode characteristic adjustment switch 22. The adjustment signal between the preceding persons is read, and sensitivity correction coefficients (acceleration sensitivity correction coefficient Ka, deceleration sensitivity correction coefficient Kd, and inter-vehicle distance sensitivity correction coefficient Kc) are set as transient correction values corresponding to each adjustment signal.

  For example, when the mode characteristic adjustment switch 22 is a step type dial switch, when it is rotated clockwise, one pulse on the plus (high sensitivity) side is output for each set angle, and when it is rotated counterclockwise, the set angle Every time one pulse on the minus (low sensitivity) side is output. The sensitivity correction coefficient calculation unit 32 counts the input pulses for each adjustment function and refers to the sensitivity correction coefficient table shown in FIG. 5 to determine the sensitivity correction coefficients Ka, Kd, Set Kc. As shown in the figure, the sensitivity correction coefficients Ka, Kd, and Kc have initial values of 1.0, and increase as the plus pulse increases, and decrease as the minus pulse increases. .

  The follow-up target vehicle speed calculation unit 33 also obtains the preceding vehicle information (the preceding inter-vehicle distance L and the preceding vehicle speed Sn [Km / h]) obtained by the IPU 6 and the actual vehicle speed detected by the vehicle speed sensor 19 (hereinafter referred to as “own vehicle speed”). The following target vehicle speed Sfo of the host vehicle with respect to the preceding vehicle based on Si [Km / h] and the engine mode (any one of the normal mode M1, the save mode M2, and the power mode M3) selected by the mode selection switch 18 Is calculated from the following equation (1).

Sfo ← Sn + Sα (1)
Here, Sα is the tracking response speed [Km / h], and is set according to the difference (inter-vehicle distance deviation) ΔL (= L−Lo) between the preceding inter-vehicle distance L and the target inter-vehicle distance Lo set by the cruise control switch 17. Is done. That is, in the follow-up traveling during the ACC control, as shown in FIG. 6A, when the preceding inter-vehicle distance L is longer than the target inter-vehicle distance Lo (ΔL> 0), the host vehicle speed Si is accelerated to increase the target inter-vehicle distance. It is necessary to hold Lo. Conversely, as shown in FIG. 5B, when the preceding inter-vehicle distance L is shorter than the target inter-vehicle distance Lo (ΔL <0), it is necessary to reduce the host vehicle speed Si to ensure the target inter-vehicle distance Lo. Therefore, since ΔL = 0 when Lo = L, the tracking response speed Sα = 0 is set.

  The tracking response speed Sα is set for each engine mode with reference to the inter-vehicle distance deviation map shown in FIG. 7 based on the inter-vehicle distance deviation ΔL. The characteristics of the inter-vehicle distance deviation map shown in FIG. 7 will be described.

  The tracking response speed Sα is a response strength when attempting to maintain the target inter-vehicle distance Lo, and is a non-linear characteristic that increases from the minus side to the plus side through the center value (ΔL = 0) with respect to the inter-vehicle distance deviation ΔL. have. In addition, the tracking response speed Sα in the save mode has a gradual rise characteristic while the tracking response speed Sα in the power mode has a sharp rise characteristic, compared to the tracking response speed Sα in the normal mode. ing. As a result, the driver can obtain an acceleration feeling equivalent to a normal acceleration operation by the accelerator pedal operation.

  Therefore, when the inter-vehicle distance deviation ΔL becomes a large value toward the plus side or the minus side in the follow-up traveling, when the save mode is selected as the engine mode, the vehicle is gradually accelerated or decelerated compared to the normal mode, Control is performed so that the preceding inter-vehicle distance L slowly approaches the target inter-vehicle distance Lo. On the other hand, when the power mode is selected as the engine mode, control is performed to bring the preceding inter-vehicle distance L closer to the target inter-vehicle distance Lo by relatively rapid acceleration or deceleration as compared with the normal mode.

  At that time, an acceleration gradient is calculated from the amount of change in the follow target vehicle speed Sfo, and the acceleration gradient is compared with the acceleration guard value gradient. When the acceleration gradient is larger than the acceleration guard value gradient, the target tracking vehicle speed Sfo is limited by the acceleration guard value. The gradient of the acceleration guard value is set for each engine mode (normal mode M1, save mode M2, power mode M3). As shown in FIG. 8, the gradient of the acceleration guard value in the normal mode indicated by a thin line is shown. On the other hand, the gradient of the acceleration guard value in the save mode indicated by the broken line is set gently, and the gradient of the acceleration guard value in the power mode indicated by the alternate long and short dash line is set to be steep. As shown in the figure, for example, in follow-up traveling, when the preceding vehicle is accelerated as indicated by a two-dot chain line from a state where the preceding vehicle is traveling at a low speed at a constant speed, the following target vehicle speed Sfo calculated based on the equation (1) It is also accelerated with a certain gradient. In this case, the acceleration (gradient) of the tracking target vehicle speed Sfo indicated by the thick line in the figure is steeper than the acceleration guard value in the save mode indicated by the broken line and is gentler than the gradient of the acceleration guard value in the normal mode indicated by the thin line. In this case, when the power mode or the normal mode is selected as the engine mode, the follow target vehicle speed Sfo calculated by the equation (1) is output as it is.

  On the other hand, when the save mode is selected as the engine mode, the acceleration of the following target vehicle speed Sfo calculated by the equation (1) is steeper than the gradient of the acceleration guard value in the save mode. The acceleration of the following target vehicle speed Sfo is limited by the gradient of the acceleration guard value in the save mode.

  By the way, since this acceleration guard value is for restricting excessive acceleration during follow-up running, in normal follow-up running (Ka, Kd, Kc = 1.0), the following target calculated by equation (1) is used. The vehicle speed Sfo does not exceed the acceleration guard value. For example, when the save mode is selected as the engine mode, the tracking response speed Sα in the equation (1) shows a gradual change with respect to the inter-vehicle distance deviation ΔL, and therefore the acceleration (gradient of the tracking target vehicle speed Sfo) ) Is not a steep slope as shown by a thick line in FIG. 8, but is accelerated with a gentler slope than the slope of the acceleration guard value in the save mode. In this case, when the preceding vehicle is not captured, the preceding vehicle speed Sn and the preceding inter-vehicle distance L are not detected, and therefore the follow target vehicle speed Sfo is not set. The acceleration guard value is corrected by an acceleration sensitivity correction coefficient Ka, which will be described later.

  The tracking flag calculation unit 34 reads the preceding vehicle capture signal from the IPU 6, sets the tracking flag Ffo when the preceding vehicle is captured (Ffo ← 1), and clears when the preceding vehicle is not captured (Ffo ← 0).

  The control target vehicle speed calculation unit 35 first corrects the target inter-vehicle distance Lo set by the driver by operating the inter-vehicle setting switch with the reciprocal of the inter-vehicle distance sensitivity correction coefficient Kc obtained by the sensitivity correction coefficient calculation unit 32. Then, a new target inter-vehicle distance Lo is set (Lo ← (1 / Kc) · Lo). Accordingly, when the driver sets the inter-vehicle distance sensitivity correction coefficient Kc to the high sensitivity (Kc> 1) side, the target inter-vehicle distance Lo is set to be short, and when the driver is set to the low sensitivity (1 <Kc) side, it is set to be long.

  Next, the target vehicle speed St (set vehicle speed Sst) set by the target vehicle speed calculation unit 31, each sensitivity correction coefficient (acceleration sensitivity correction coefficient Ka, deceleration sensitivity correction coefficient Kd) obtained by the sensitivity correction coefficient calculation unit 32, and follow target vehicle speed calculation. Based on the tracking target vehicle speed Sfo obtained by the unit 33 and the value of the tracking flag Ffo set by the tracking flag calculation unit 34, the control target vehicle speed So is obtained, and the upper limit of the control target vehicle speed So is regulated in each operation region. Set the upper limit guard value for the target vehicle speed. This target vehicle speed upper limit guard value is set for each driving region, and is set at the time of a transition to a constant speed traveling or one set at the time of following traveling.

  Specifically, when the tracking flag Ffo is cleared (Ffo = 0), that is, in the constant speed running in which the preceding vehicle is not captured, the target vehicle speed St has priority, and the control target vehicle speed is set at the target vehicle speed St. So is set (So ← St). Further, when the tracking flag Ffo is set (Ffo = 1), that is, when the preceding vehicle is captured, the follow target vehicle speed Sfo has priority, and the control target vehicle speed So is set by the follow target vehicle speed Sfo. (So ← Sfo). The upper limit of the follow target vehicle speed Sfo is the target vehicle speed St (set vehicle speed Sst).

  When the preceding vehicle is captured, the preceding inter-vehicle distance L is first compared with the target inter-vehicle distance Lo. If the preceding inter-vehicle distance L is longer than the target inter-vehicle distance Lo (L> Lo), the following target vehicle speed Sfo is set. The vehicle speed Sst is set (Sfo ← Sst), and the control target vehicle speed So is set to a value at which the actual host vehicle speed Si converges to the set vehicle speed Sst.

  Then, when the preceding inter-vehicle distance L converges to the target inter-vehicle distance Lo (L≈Lo), the preceding vehicle following travel is performed, and the following target vehicle speed Sfo is set so that the preceding inter-vehicle distance L maintains the target inter-vehicle distance Lo. The target vehicle speed So for control is set at the target vehicle speed Sfo. At this time, if the preceding vehicle accelerates, the acceleration (gradient) of the tracking target vehicle speed Sfo is set for each engine mode (normal mode M1, save mode M2, power mode M3) in the tracking target vehicle speed calculation unit 33 described above. It is regulated by the acceleration guard value. This acceleration guard value is corrected by an acceleration sensitivity correction coefficient Ka set by the driver, and the driver's preference is reflected in the acceleration characteristics during the follow-up running by this correction.

  When the preceding vehicle decelerates and the preceding inter-vehicle distance L becomes shorter than the target inter-vehicle distance Lo, a new control target vehicle speed So is set by multiplying the follow target vehicle speed Sfo by the deceleration sensitivity correction coefficient Kd (So). ← Kd · Sfo). The deceleration sensitivity correction coefficient Kd is a coefficient for the driver to set the deceleration sensitivity according to his / her preference, and thus the driver's preference is reflected in the deceleration characteristics during the follow-up traveling.

  Generally, when a driver selects one engine mode from the normal mode M1, the save mode M2, and the power mode M3, the driver tends to use the engine mode continuously. In this case, depending on the acceleration guard value and the deceleration characteristic set in the normal follow-up traveling, depending on the driver, for example, the engine is accelerated during the start acceleration from the stop state during the follow-up travel or the follow-up acceleration operation or the deceleration operation during the travel. Even when the save mode M2 is selected as a mode, agile acceleration characteristics or deceleration characteristics may be required. Conversely, even when the power mode M3 is selected as the engine mode, there are cases where a gentle acceleration characteristic or deceleration characteristic is required. The acceleration sensitivity correction coefficient Ka and the deceleration sensitivity correction coefficient Kd described above finely adjust the acceleration characteristic or the deceleration characteristic so that the acceleration / deceleration operation according to the driver's request can be realized. For the deceleration characteristics, no guard value is set, and it is directly reflected in the throttle opening.

  In this case, as shown in FIG. 9, when following acceleration is performed following the acceleration operation of the preceding vehicle, the following target vehicle speed Sfo does not generate an acceleration greater than the acceleration guard value set in the following target vehicle speed calculation unit 33. However, in this case, if the following target vehicle speed Sfo of the wrong acceleration is output from the following target vehicle speed calculation unit 33, the acceleration is sudden. Similarly, the maximum value of the follow target vehicle speed Sfo is the set vehicle speed Sst, but there may be a case where the follow target vehicle speed Sfo is set to an incorrect value equal to or higher than the set vehicle speed Sst, that is, the target vehicle speed St.

  Therefore, as shown in FIG. 9, in the follow-up running in which the tracking flag Ffo is set (Ffo = 1), the follow-up target vehicle speed Sfo that is set when the vehicle is accelerated following the acceleration operation of the preceding vehicle is regulated. The following acceleration guard value is set. Further, a set vehicle speed guard value that restricts the upper limit value of the follow target vehicle speed Sfo is set. The following acceleration guard value is set for each engine mode, and has a role as a safety function. The gradient of the following acceleration guard value is set to be slightly steep with respect to the acceleration guard value for each engine mode corrected with the acceleration sensitivity correction coefficient Ka. The set vehicle speed guard value is set by the set vehicle speed Sst that is the maximum vehicle speed during ACC control, that is, the target vehicle speed St.

  When the tracking flag Ffo is cleared (Ffo ← 0), that is, when starting constant speed running, first, a constant speed running start guard value is set first. The constant speed travel start guard value is set to a value that is decelerated from the current host vehicle speed Si by a set speed ΔSg (for example, 5 [Km / h]). Therefore, since the control target vehicle speed So is always set at the constant speed travel start guard value at the start of constant speed travel, the preceding vehicle is lost momentarily and captured again at the start of constant speed travel. However, good drivability can be obtained without giving the driver a feeling of jumping out of the vehicle.

  Further, after the shift to the constant speed running, when the own vehicle speed Si is returned to the target vehicle speed St, the constant speed return acceleration guard value is set. Therefore, the control target vehicle speed So is gradually regulated by the constant speed return acceleration guard value. Increased speed. When the target vehicle speed So for control is suddenly set to the target vehicle speed St (set vehicle speed Sst) when switching from the follow-up travel to the constant speed travel, if the deviation between the own vehicle speed Si and the target vehicle speed St is large, the vehicle accelerates rapidly. However, in this embodiment, since the acceleration gradient is regulated by the constant speed return acceleration guard value, there is no sudden acceleration, and this constant speed return acceleration guard value is set for each engine mode. Therefore, good drivability can be obtained.

  The target vehicle speed So for control is read by the ACC control required horsepower (hereinafter referred to as “ACC required horsepower”) calculation unit 36 and the required braking force calculation unit 42.

  The ACC required horsepower calculating unit 36 is configured to cause the host vehicle speed Si to reach the control target vehicle speed So based on the speed difference ΔS (= So−Si) between the control target vehicle speed So and the host vehicle speed Si detected by the vehicle speed sensor 19. The ACC required horsepower HPs is obtained by a calculation formula or a table search.

  The ACC request horsepower HPs is read by the ACC request torque calculator 37. The ACC required torque calculation unit 37 obtains the ACC required torque Tcs from the calculation formula based on the ACC required horsepower HPs and the engine speed Ne (Tcs = k · (HPs / Ne), where k is a coefficient).

  On the other hand, the accelerator required torque calculation unit 38 performs the engine mode selected by the driver based on the accelerator opening θa that is the amount of depression of the accelerator pedal detected by the accelerator opening sensor 14 and the engine speed Ne during the ACC control. Accelerator required torque Tacs is obtained with reference to a mode map corresponding to (see FIG. 4).

  The required torque selection calculation unit 39 compares the ACC required torque Tcs with the accelerator required torque Tacs, and sets the higher one as the required torque Ts. Therefore, in a state where the driver releases the accelerator pedal, the ACC required torque Tcs is set as the required torque Ts (Ts ← Tcs). On the other hand, when the driver depresses the accelerator pedal and the accelerator request torque Tacs higher than the ACC request torque Tcs is output, the ACC control is temporarily suspended, and the accelerator request torque Tacs is set as the request torque Ts ( Ts ← Tacs).

  The ACC required torque Tcs is the first and target vehicle speed upper limit guard value described above with reference to the characteristics during acceleration / deceleration operation without referring to the mode map (see FIG. 4) that is referred to during normal operation that travels by operating the accelerator pedal. Since the calculation is not complicated and the upper limit guard value for the target vehicle speed is set according to the engine mode selected by the driver, the engine output characteristics during normal operation and It can be adapted and good drivability can be obtained.

  Further, the required torque Ts is compared with the upper limit guard value for required torque. If the required torque Ts exceeds the upper limit guard value for required torque, the required torque Ts is set as the upper limit guard value for required torque. The upper limit guard value for required torque is set for each engine mode, and is set to the maximum torque when the accelerator pedal is fully depressed in each engine mode. In the normal operation in which the accelerator pedal is operated, the throttle valve 4 is not opened more greatly than when the accelerator pedal is fully depressed. In the ACC control, the throttle valve 4 is opened from the required torque. Therefore, the throttle valve 4 can be opened more greatly than when the accelerator pedal is fully depressed. However, in the present embodiment, the required torque Ts is regulated by the upper limit guard value for required torque, so that the throttle opening does not open larger than when the accelerator pedal is fully depressed. This upper limit guard value for required torque can be set arbitrarily, so that it is lower than the maximum torque when the accelerator pedal is fully depressed in each engine mode, for example, the maximum torque when the accelerator pedal is fully depressed. It is also possible to set to about 80 [%].

  Then, the required torque Ts is read into the target throttle opening calculation unit 40 and the pseudo accelerator opening calculation unit 41.

  Based on the required torque Ts, the target throttle opening calculating unit 40 obtains a target throttle opening θαs [%] corresponding to the required torque Ts and outputs it to the E / G_ECU 8. On the other hand, the pseudo accelerator opening calculation unit 41 refers to a mode map (see FIG. 4) corresponding to the engine mode selected by the driver based on the required torque Ts and the engine speed Ne, and sets the pseudo accelerator opening θha. Obtained by reverse calculation and output to T / M_ECU 9.

  On the other hand, the required braking force calculation unit 42 reads the control target vehicle speed So and the own vehicle speed Si obtained by the control target vehicle speed calculation unit 35, and sets the predetermined determination time to until the own vehicle speed Si reaches the control target vehicle speed So. If it does not decrease even after a lapse of time, a required braking force Tb is obtained from the difference between the control target vehicle speed So and the host vehicle speed Si, and this required braking force Tb is corrected with the deceleration sensitivity correction coefficient Kd to make a new requirement. The braking force Tb is set (Tb ← Kd · Tb). Then, the brake booster 16 is operated with a control amount corresponding to the required braking force Tb, and the brake wheel cylinder 16a is operated to forcibly decelerate. Since the required braking force Tb is corrected by the deceleration sensitivity correction coefficient Kd set by the driver, the deceleration performance according to the driver's preference can be obtained.

1 ... own vehicle,
5 ... In-vehicle camera,
5a ... main camera,
5b ... Sub camera,
7: Inter-vehicle distance control device,
8 ... Engine control device,
9: Transmission control device,
12 ... Engine speed sensor,
13. Intake air amount sensor
14 ... accelerator opening sensor,
15 ... Throttle opening sensor,
16 ... Brake booster,
18 ... mode selection switch,
19 ... Vehicle speed sensor,
22: Mode characteristic adjustment switch,
Ka: Acceleration sensitivity correction coefficient,
Kc: Inter-vehicle distance sensitivity correction coefficient,
Kd: deceleration sensitivity correction coefficient,
L ... Distance between preceding cars
Lo: Target inter-vehicle distance,
M1 ... Normal mode,
M2 ... save mode,
M3 ... power mode,
Mp1 ... Normal mode map,
Mp2 ... Save mode map,
Mp3 ... power mode map,
Ne ... engine speed,
Sfo ... Following target vehicle speed,
Si ... own vehicle speed,
Sn ... preceding vehicle speed,
So: Target vehicle speed for control,
Sst ... set vehicle speed,
St ... Target vehicle speed,
Sα: Tracking response speed,
Tb: Required braking force,

Claims (3)

Preceding vehicle detection means for detecting a preceding vehicle traveling in front of the host vehicle;
Driving state detecting means for detecting the driving state of the host vehicle;
Driving mode selection means for selecting one driving mode by an external operation from a plurality of driving modes having different output characteristics;
Travel control means for following the vehicle so that the inter-vehicle distance between the host vehicle and the preceding vehicle converges to a preset target inter-vehicle distance according to the output characteristics corresponding to the one travel mode selected by the travel mode selection means; In a travel control device comprising:
Characteristic adjustment means for setting a transient correction value for adjusting the transient characteristic set for each of the travel modes by an external operation;
The travel control device, wherein the travel control unit corrects the transient characteristic set for each travel mode with the transient correction value and sets a new transient characteristic. The plurality of travel modes are a plurality of engine modes having different engine output characteristics,
The transient characteristic is an acceleration / deceleration characteristic when traveling following the preceding vehicle,
2. The travel control apparatus according to claim 1, wherein the travel control unit sets a new acceleration / deceleration characteristic by correcting the acceleration / deceleration characteristic with the transient correction value set by the characteristic adjustment unit. The characteristic adjusting means sets an inter-vehicle correction value for adjusting the target inter-vehicle distance in addition to the transient correction value,
3. The travel control according to claim 1, wherein the travel control unit sets a new target inter-vehicle distance by correcting the target inter-vehicle distance set in the selected travel mode with the inter-vehicle correction value. apparatus.

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