CN111391817A - Vehicle control device - Google Patents

Abstract

The present invention provides a vehicle control device, comprising: a parking instruction unit (601) that instructs travel in a parking mode in which a vehicle (100) is moved into or out of a parking lot (111), and a transmission control unit (604) that controls a transmission (1). When a parking command unit (601) instructs a vehicle to travel in a parking mode, a transmission control unit (604) controls the transmission so that the maximum gear ratio of the transmission (1) is smaller than when the vehicle is not instructed to travel in the parking mode.

Description

Vehicle control device

Technical Field

The present invention relates to a vehicle control device that controls an operation when a vehicle is parked and running.

Background

When a vehicle is driven into (parked) or out of (taken out of) a parking lot, as described in patent document 1, it is general to operate a shift position so as to be in a driving range and to run the vehicle by utilizing a creep phenomenon while operating a foot brake in a state where an engine is rotated at an idle rotation speed without operating an accelerator pedal by a driver. Since such parking travel is performed at a low speed, the automatic transmission is normally shifted to a low speed.

However, when the automatic transmission is shifted to a low gear, the driving torque at the time of parking travel by the creep phenomenon becomes excessively large, and the braking performance of the vehicle deteriorates.

Documents of the prior art

Patent document 1: japanese patent laid-open No. 5-060224 (JPH 5-060224A).

Disclosure of Invention

One aspect of the present invention is a vehicle control device for controlling a traveling operation of a vehicle including an engine and a transmission that changes a rotation speed generated by driving of the engine and transmits the changed rotation speed to wheels, the vehicle control device including: a parking instruction section that instructs traveling in a parking mode in which a vehicle is driven into or out of a parking lot; and a transmission control unit that controls the transmission. When the parking command unit instructs the vehicle to travel in the parking mode, the transmission control unit controls the transmission so that the maximum gear ratio of the transmission is smaller than when the vehicle is not instructed to travel in the parking mode.

Drawings

The objects, features and advantages of the present invention are further clarified by the following description of the embodiments in relation to the accompanying drawings.

Fig. 1 is a diagram schematically showing a part of a running drive system of a vehicle to which a vehicle control device according to an embodiment of the present invention is applied.

Fig. 2A is a diagram showing a torque transmission path when the vehicle of fig. 1 establishes the 1 st gear.

Fig. 2B is a diagram showing a torque transmission path when the vehicle of fig. 1 establishes 3 rd gear.

Fig. 3 is a block diagram schematically showing the overall configuration of a vehicle control system including a vehicle control device according to an embodiment of the present invention.

Fig. 4 is a plane showing an example of a traveling operation of the vehicle performed by the vehicle control system of fig. 3.

Fig. 5 is a diagram showing a relationship between an engine speed and a creep torque.

Fig. 6 is a diagram showing an example of the operation characteristics obtained when creep running is performed in the 1 st gear.

Fig. 7 is a block diagram showing a configuration of a main part constituting a vehicle control device according to an embodiment of the present invention.

Fig. 8 is a flowchart showing an example of processing performed by the controller of fig. 7.

Fig. 9 is a timing chart showing an example of an operation performed by the vehicle control device according to the embodiment of the present invention.

Detailed Description

Embodiments of the present invention will be described below with reference to fig. 1 to 9. Fig. 1 is a diagram schematically showing a configuration of a part (mainly, a transmission 1) of a travel drive system of a vehicle 100 to which a vehicle control device according to an embodiment of the present invention is applied. Vehicle 100 is configured as a hybrid vehicle including engine 2 and motor 3, for example.

A clutch mechanism C that transmits or does not transmit the torque of the engine 2 to the transmission 1 is provided between the transmission 1 and the engine 2. The clutch mechanism C is constituted by, for example, a wet double clutch, and includes a1 st clutch C1 and a2 nd clutch C2. The clutch mechanism C may be formed by a dry-type dual clutch.

The transmission 1 is, for example, a stepped transmission, and has a gear mechanism 10 that shifts rotation of at least one of an engine 2 and a motor 3 input to the transmission 1 at a speed ratio according to a speed step. The torque output via the gear mechanism 10 is transmitted to the drive wheels via a working gear mechanism, a drive shaft, and the like, not shown, and thereby the vehicle travels. Further, the torque of the engine 2 can be output to the transmission 1 via the torque converter.

The gear mechanism 10 is disposed substantially parallel to each other, and has a plurality of rotatable shafts supported rotatably, that is, a1 st main input shaft 11, a2 nd main input shaft 12, a sub input shaft 13, an output shaft 14, an idle shaft 15, and a reverse rotation shaft 16. The 2 nd main input shaft 12 is formed to be hollow coaxially with the 1 st main input shaft 11 and so as to surround the 1 st main input shaft 11. The transmission 1 is, for example, an automatic transmission of forward 7 speed and reverse 1 speed.

The motor 3 is composed of, for example, a 3-phase DC brushless motor, and includes a rotor 3a rotatably supported in a housing of the motor 3, not shown, and a stator 3b disposed around the rotor 3a and fixed to the housing. One end of the 1 st main input shaft 11 is connected to the rotor 3a of the motor 3, and the 1 st main input shaft 11 is rotatable integrally with the rotor 3 a. The stator 3b has a coil wound around a stator core, and the coil is electrically connected to the battery through a power drive unit. The action of the power drive unit is controlled by a controller (fig. 3).

The other end portion of the 1 st main input shaft 11 is connected to the output shaft 2a of the engine 2 through the 1 st clutch C1, and the 1 st main input shaft 11 and the output shaft 2a are engaged or disengaged according to the disengaging engagement of the 1 st clutch C1. That is, when the 1 st clutch C1 is engaged, the 1 st main input shaft 11 is engaged with the output shaft 2a, and torque from the engine 2 is input to the 1 st main input shaft 11. On the other hand, when the 1 st clutch C1 is disengaged, the 1 st main input shaft 11 is disengaged from the output shaft 2a, and the input of torque from the engine 2 is cut off.

The 1 st clutch C1 is a clutch for odd-numbered gears, and the 1 st gear drive gear 21, the 3 rd gear drive gear 23, the 7 th gear drive gear 27, and the 5 th gear drive gear 25 are disposed on the 1 st main input shaft 11 in this order from the electric motor 3 side. These drive gears 21, 23, 25, and 27 are supported on the outer peripheral surface of the 1 st main input shaft 11 through bearings so as to be rotatable relative to the 1 st main input shaft 11. The 1 st gear drive gear 21 and the 3 rd gear drive gear 23 are provided to be rotatable integrally. The planetary gear mechanism 20 is disposed between the rotor 3a of the electric motor 3 and the 1 st-gear drive gear 21.

One end portion of the 2 nd main input shaft 12 is connected to the output shaft 2a of the engine 2 through a2 nd clutch C2, and the 2 nd main input shaft 12 and the output shaft 2a are engaged or disengaged according to the disengaging engagement of the 2 nd clutch C2. That is, when the 2 nd clutch C2 is engaged, the 2 nd main input shaft 12 is engaged with the output shaft 2a, and torque from the engine 2 is input to the 2 nd main input shaft 12. On the other hand, when the 2 nd clutch C2 is disengaged, the 2 nd main input shaft 12 is disengaged from the output shaft 2a, and the input of torque from the engine 2 is cut off.

The gear 31 is fixed to the other end portion of the 2 nd main input shaft 12. The gear 31 meshes with an idle gear 32 fixed to the idle shaft 15, and the idle gear 32 meshes with a gear 33 fixed to the sub input shaft 13. Thereby, the torque of the 2 nd main input shaft 12 is transmitted to the sub input shaft 13 via the idle gear 32, and the sub input shaft 13 rotates together with the 2 nd main input shaft 12.

The 2 nd clutch C2 is a clutch for even-numbered gears, and the 2 nd drive gear 22, the 6 th drive gear 26, and the 4 th drive gear 24 are disposed on the sub input shaft 13 in this order from the electric motor 3 side. The drive gears 22, 24, and 26 are supported on the outer peripheral surface of the sub input shaft 13 by bearings so as to be rotatable relative to the sub input shaft 13.

The gear 34 is fixed to one end of the counter shaft 16. Gear 34 meshes with idler gear 32 whereby torque from the 2 nd main input shaft 12 is input to the countershaft 16. The reverse drive gear 28 is supported by the outer peripheral surface of the reverse shaft 16 via a bearing so as to be rotatable relative to the reverse shaft 16. The counter drive gear 28 meshes with a counter driven gear 35 fixed to the 1 st main input shaft 11 between the 5 th drive gear 25 and the gear 31.

From the motor 3 side, a 2-3 stage driven gear 41, a 6-7 stage driven gear 42, a 4-5 stage driven gear 43, a parking gear 44, and a final drive gear 45 are fixed to the output shaft 14 in this order. The 2-3 th driven gear 41 is meshed with the 2 nd drive gear 22 and the 3 rd drive gear 23, respectively. The 6-7 th driven gear 42 is meshed with the 6 th drive gear 26 and the 7 th drive gear 27, respectively. The 4-5 driven gear 43 meshes with the 4-gear drive gear 24 and the 5-gear drive gear 25, respectively.

The parking gear 44 is engaged with an engagement claw of a parking gear mechanism, not shown, and can lock or unlock the gear mechanism 10 according to the operation of the parking gear mechanism. The torque of the transmission 1 is transmitted to left and right drive wheels 47 via a final gear 45 and a differential gear mechanism 46. Braking force is applied to the drive wheels 47 by the brake device 4. The brake device 4 is configured as a disc brake that operates by hydraulic pressure, for example.

The transmission 1 has: a1 st-gear synchronizing mechanism SY1 for engaging the 1 st main input shaft 11 with the 1 st drive gear 21 that is relatively rotatable with respect to the 1 st main input shaft 11, a 3-7 st-gear synchronizing mechanism SY2 for engaging the 1 st main input shaft 11 with either one of the 3 st-gear drive gear 23 and the 7 th-gear drive gear 25 that are relatively rotatable with respect to the 1 st main input shaft 11, a 5 th-gear synchronizing mechanism SY3 for engaging the 1 st main input shaft 11 with the 5 th drive gear 25 that is relatively rotatable with respect to the 1 st main input shaft 11, the 2-6 range synchronizing mechanism SY4 that engages the sub input shaft 13 with either one of the 2 nd drive gear 22 and the 6 th drive gear 26 that are relatively rotatable with respect to the sub input shaft 13, the 4 th synchronizing mechanism SY5 that engages the 4 th drive gear 24 that is relatively rotatable with respect to the sub input shaft 13 with the sub input shaft 13, and the reverse synchronizing mechanism SY6 that engages the reverse drive gear 28 that is relatively rotatable with respect to the reverse shaft 16 with the reverse shaft 16.

Note that the 1-gear synchronizing mechanism SY1, the 3-7-gear synchronizing mechanism SY2, the 5-gear synchronizing mechanism SY3, the 2-6-gear synchronizing mechanism SY4, the 4-gear synchronizing mechanism SY5, and the reverse rotating synchronizing mechanism SY6 may be simply referred to as synchronizing mechanisms SY, respectively. The synchronization mechanism SY is driven by hydraulic pressure, for example. This hydraulic pressure is applied to the synchronizing mechanism SY in accordance with switching of a control valve not shown.

Fig. 2A and 2B are diagrams showing torque transmission paths when the 1 st and 3 rd gears are established, respectively. As shown in fig. 2A, in the state where the 1 st gear is established, the output shaft 2A of the engine 2 is engaged with the 1 st main input shaft 11 via the 1 st clutch C1, and the 1 st gear drive gear 21 is engaged with the planetary gear mechanism 20 via the 1 st synchronizing mechanism SY 1. Accordingly, the torque of the engine 2 is transmitted to the output shaft 14 via the 1 st clutch C1, the 1 st main input shaft 11, the planetary gear mechanism 20, the 1 st drive gear 21, the 3 rd drive gear 23, and the 2-3 rd driven gear 41, and the vehicle 100 travels in the 1 st gear.

As shown in fig. 2B, in the state where the 3 th gear is established, the output shaft 2a of the engine 2 is engaged with the 1 st main input shaft 11 via the 1 st clutch C1, and the 3 rd drive gear 23 is engaged with the 1 st main input shaft 11 via the 3-7 th synchronization mechanism SY 2. The torque of the engine 2 is thereby transmitted to the output shaft 14 via the 1 st clutch C1, the 1 st main input shaft 11, the 3 rd drive gear 23, and the 2-3 rd driven gear 41, and the vehicle 100 travels in 3 rd gear. Note that, although not shown, the other shift range can be switched similarly by switching the clutch mechanism C and the synchronizing mechanism SY. The gear ratio of the transmission 1 increases as it changes to the low speed side, and the 1 st gear is the maximum. The larger the gear ratio, the larger the maximum running driving force.

In the present embodiment, the vehicle 100 is configured as an autonomous vehicle having an autonomous function. In addition, the vehicle 100 can travel not only in an automatic driving mode in which the driver does not need to perform driving operation, but also in a manual driving mode in which the driver performs driving operation.

Fig. 3 is a block diagram schematically showing a basic overall configuration of a vehicle control system 101 that controls the autonomous vehicle 100. As shown in fig. 3, the vehicle control system 101 mainly includes a controller 60, and an external sensor group 51, an internal sensor group 52, an input/output device 53, a GPS device 54, a map database 55, a navigation device 56, a communication unit 57, and a travel actuator AC, which are communicably connected to the controller 60, respectively.

The external sensor group 51 is a general term for a plurality of sensors (external sensors) that detect an external condition that is a peripheral condition of the vehicle 100. For example, the external sensor group 51 includes: the present invention relates to a vehicle including a laser radar that measures a distance from the vehicle 100 to a peripheral obstacle by measuring scattered light of the vehicle 100 in all directions with respect to irradiation light, a radar that detects another vehicle, an obstacle, and the like in the periphery of the vehicle 100 by irradiating electromagnetic waves and detecting reflected waves, and a camera that is mounted on the vehicle 100, includes an image pickup device such as a CCD and a CMOS, and picks up an image of the periphery (front, rear, and side) of the vehicle 100. Signals from the external sensor group 51 are input to the controller 60.

The internal sensor group 52 is a general term for a plurality of sensors (internal sensors) that detect the running state of the vehicle 100. For example, the internal sensor group 52 includes: a vehicle speed sensor that detects a vehicle speed of vehicle 100, an acceleration sensor that detects acceleration in the front-rear direction and acceleration in the left-right direction of vehicle 100, respectively, an engine speed sensor that detects a speed of engine 2, a yaw rate sensor that detects a rotational angular velocity at which the center of gravity of vehicle 100 rotates about the vertical axis, a throttle opening sensor that detects an opening degree of a throttle valve (throttle opening degree), and the like. The internal sensor group 52 also includes sensors that detect driving operations of the driver in the manual driving mode, for example, operations of an accelerator pedal, a brake pedal, an operation of a steering wheel, and the like. The detection signals from the internal sensor group 52 are input to the controller 60.

The input/output device 53 is a generic term for a device that inputs a command from the driver and outputs information to the driver. For example, the input/output device 53 includes: various switches for inputting various commands by operating the operation member, a microphone for inputting commands by voice, a display unit for providing information to the occupant via a display image, a speaker for providing information to the occupant by voice, and the like. The various switches include a manual/automatic changeover switch that instructs to perform any one of an automatic driving mode and a manual driving mode.

The manual/automatic changeover switch is configured as a switch that can be manually operated by a driver, for example, and outputs a command for changing over to an automatic driving mode in which the automatic driving function is activated or a manual driving mode in which the automatic driving function is deactivated in accordance with a switch operation. When a predetermined running condition is satisfied, a command is issued to switch from the manual drive mode to the automatic drive mode or from the automatic drive mode to the manual drive mode regardless of the operation of the manual/automatic changeover switch. That is, the mode may be automatically switched by a manual/automatic switching switch instead of manually. The signal from the input/output device 53 is input to the controller 60. A signal is input from the controller 60 to the input/output device 53.

The GPS device 54 has a GPS receiver that receives positioning signals from a plurality of GPS satellites, and measures the absolute position (latitude, longitude, and the like) of the vehicle 100 from the signals received by the GPS receiver. Signals from the GPS device 54 are input to the controller 60.

The map database 55 is a device for storing general map information used in the navigation device 56, and is constituted by a hard disk, for example. The map information includes: position information of a road, information of a road shape (curvature, etc.), and position information of an intersection or a fork. The map information stored in the map database 55 is different from the high-precision map information stored in the storage unit 62 of the controller 60.

The navigation device 56 is a device that searches for a target route on a road to a destination input by the driver and performs guidance along the target route. The input of the destination and the guidance along the target route are performed by the input/output device 53. The target route is calculated based on the current position of the own vehicle obtained from the GPS device 54 and the map information stored in the map database 55. Signals from the navigation device 56 are input to the controller 60.

The communication unit 57 communicates with various servers not shown in the drawings via a network including a wireless communication network such as an internet line, and acquires map information, traffic information, and the like from the servers at regular intervals or at arbitrary timing. The communication unit 57 outputs the acquired map information to the map database 55 and the storage section 62 by communicating with the controller 60, thereby updating the map information. The acquired traffic information includes traffic jam information, signal information such as the remaining time of the signal changing from red to green, and the like.

The actuator AC is a travel actuator for controlling travel of the vehicle 100. The actuator AC includes various actuators that operate in accordance with electric signals from the controller 60. For example, a throttle actuator for adjusting the opening degree of a throttle valve of the engine 2, a clutch actuator for driving the clutch C, a gear shift actuator for driving the synchronizing mechanism SY of the transmission 1, a brake actuator for actuating the brake device 4, a steering actuator for driving the steering device, and the like. These actuators may include control valves and the like that control the flow of hydraulic pressure for driving the electric motor and the actuators.

The controller 60 includes an Electronic Control Unit (ECU). Note that a plurality of ECUs having different functions, such as an engine control ECU and a transmission control ECU, may be provided separately, but fig. 23 shows the controller 60 as a set of these ECUs for convenience. The controller 60 includes a computer having an arithmetic unit 61 such as a CPU (microprocessor) that mainly performs processing related to automatic driving, a storage unit 62 such as a ROM, a RAM, and a hard disk, and other peripheral circuits (not shown) such as an input/output interface.

The storage unit 62 stores high-precision detailed map information including center position information of a lane, boundary information of a lane position, and the like. More specifically, road information, traffic control information, residence information, facility information, telephone number information, parking lot information, and the like are stored as the map information. The road information includes: information indicating road types such as an expressway, a toll road, and a national road, information such as the number of lanes of a road, the width of each lane, the gradient of a road, the three-dimensional coordinate position of a road, the curvature of a curve of a lane, the positions of a junction and a branch of a lane, and a road sign. The traffic control information includes: and information on whether the lane is restricted from traveling or prohibited from passing through due to construction or the like. The storage unit 62 also stores information such as a shift map (shift line map) serving as a reference of the shifting operation, programs of various controls, and thresholds used in the programs.

The calculation unit 61 has a functional configuration of a vehicle position recognition unit 63, an external recognition unit 64, an action plan generation unit 65, and a travel control unit 66.

The vehicle position recognition unit 63 recognizes the position of the vehicle 100 (vehicle position) on the map based on the position information of the vehicle 100 acquired by the GPS device 54 and the map information of the map database 55. The own vehicle position may be identified with high accuracy by using the map information (information such as the shape of the building) stored in the storage unit 62 and the peripheral information of the vehicle 100 detected by the external sensor group 51 to identify the own vehicle position. When the vehicle position can be measured by a sensor provided outside on the road or near the road, the vehicle position can be identified with high accuracy by communicating with the sensor through the communication unit 57.

The environment recognizing unit 64 recognizes an external situation around the vehicle 100 based on a signal from the external sensor group 51 such as a laser radar, a camera, or the like. For example, the position, speed, acceleration, position of a nearby vehicle (front vehicle, rear vehicle) that is traveling around the vehicle 100, position of a nearby vehicle that is parked or stopped around the vehicle 100, and position, state, and the like of other objects are recognized. Other objects include: signs, annunciators, boundary lines of roads, stop lines, buildings, railings, utility poles, billboards, pedestrians, bicycles, and the like. The states of other objects include: the color of the annunciator (red, green, yellow), the speed of movement, orientation of the pedestrian, bicycle, etc.

The action plan generating unit 65 generates a travel trajectory (target trajectory) of the vehicle 100 from the current time to the elapse of a predetermined time, for example, based on the target route calculated by the navigation device 56, the own vehicle position recognized by the own vehicle position recognition unit 63, and the external situation recognized by the external world recognition unit 64. When a plurality of trajectories exist as candidates of the target trajectory on the target route, the action plan generating unit 65 selects an optimum trajectory that satisfies the law and meets the criteria for efficient and safe travel, and sets the selected trajectory as the target trajectory. Then, the action plan generating unit 65 generates an action plan corresponding to the generated target trajectory.

The action plan includes: travel plan data set per unit time (for example, 0.1 second) during a period from a current time to a lapse of a predetermined time (for example, 5 seconds), that is, travel plan data set in association with a time per unit time. The travel plan data includes position data of the vehicle 100 per unit time and data of the vehicle state. The position data is, for example, data of a target point indicating a two-dimensional coordinate position on a road, and the vehicle state data is vehicle speed data indicating a vehicle speed, direction data indicating an orientation of the vehicle 100, and the like. The travel plan is updated per unit time.

The action plan generating unit 65 generates the target trajectory by connecting the position data per unit time in chronological order until a predetermined time (for example, 5 seconds) has elapsed from the current time. At this time, the acceleration per unit time (target acceleration) is calculated from the vehicle speed of each target point per unit time on the target trajectory (target vehicle speed). That is, the action plan generating unit 65 calculates the target vehicle speed and the target acceleration. The target acceleration may be calculated by the travel control unit 66. The driving force for achieving the target acceleration is equivalent to the required driving force. Therefore, calculating the target acceleration corresponds to calculating the required driving force.

The action plan generating unit 65 first determines the driving method when generating the target trajectory. Specifically, the following driving modes are determined: the vehicle is driven by passing a vehicle ahead, by lane change driving for changing a driving lane, by lane keeping driving for keeping a lane without deviating from the driving lane, by deceleration driving, acceleration driving, parking driving, or the like. Then, a target trajectory is generated according to the driving method. The parking travel includes a parking travel for entering (parking) the parking lot and a parking exit travel for exiting (parking) the parking lot. When the travel mode is determined to be the parking travel, the action plan generating unit 65 generates the travel plan data so that the vehicle 100 enters the parking lot recognized by the vehicle control system 101 or so that the vehicle 100 exits from the parking lot.

The travel control unit 66 controls the actuator AC so that the vehicle 100 travels along the target trajectory generated by the action plan generation unit 65 at the target vehicle speed and the target acceleration in the automatic driving mode. That is, the throttle actuator, the clutch actuator, the transmission actuator, the brake actuator, and the steering actuator are controlled so that the vehicle 100 passes a target point per unit time.

In particular, in the control of the transmission 1, the travel control unit 66 determines a target shift range corresponding to the vehicle speed and the required driving force in accordance with a predetermined shift map, and controls the shift actuator so that the shift range becomes the target shift range. Although not shown, the shift map is set to have a characteristic such that the target shift position is lower as the vehicle speed is lower, and the target shift position is the 1 st gear when the vehicle speed is equal to or lower than a predetermined value.

Fig. 4 is a plan view showing an example of the traveling operation of the vehicle 100 by the vehicle control system 101. Fig. 4 shows an example in which the vehicle 100 traveling on the road 110 is parked in the lateral direction (direction perpendicular to the lane) in the parking lot 111 facing the road 110 by automatic driving. Specifically, for example, the parking lot 111 at a predetermined position is set as the destination of the autonomous vehicle 100, and the vehicle 100 enters the parking lot 111 by autonomous driving and travels.

More specifically, as indicated by an arrow a1, when the vehicle 100 passes in front of the parking lot 111 once and the position of the parking lot 111 is recognized based on the position information acquired by the GPS device 54 and the image signal from the vehicle-mounted camera (external sensor group 51), the automatic parking mode is switched to, and the garage driving is started. In the automatic parking mode, the vehicle is driven into the parking lot 111 by reverse travel as indicated by an arrow a 2. In addition, the vehicle 100 may be switched to travel forward and then to travel backward. It is also possible to cause the vehicle 100 not to enter the parking lot 111 from the rear side but to enter from the front side.

In the automatic parking mode, travel control unit 66 outputs a control signal to actuator AC so that vehicle 100 travels using creep torque. More specifically, the braking force of the brake device 4 is controlled so that the travel control unit 66 outputs a control signal to the throttle actuator to control the engine speed to a predetermined idle speed, outputs a control signal to the clutch actuator to control the clutch C to the half-clutch state, and further outputs a control signal to the brake actuator to cause the vehicle 100 to travel at the target vehicle speed.

However, while the vehicle 100 travels at a low speed during parking (during parking in a garage or during leaving from a garage), the following problem arises when the shift position of the transmission 1 is controlled to 1 st gear according to the shift map. Fig. 5 is a diagram showing a relationship between engine speed Ne and creep torque Tc. The characteristics f1 to f3 in the figure represent characteristics in 1 st, 2 nd, and 3 rd gears, respectively. Generally, the creep torque Tc is proportional to the square of the engine speed Ne and the gear ratio of the transmission 1. Therefore, as shown in fig. 5, the creep torque Tc increases with an increase in the engine rotation speed Ne, and the lower the speed, the higher the shift creep torque Tc. Therefore, when the engine speed is the idle speed Nei, the creep torque of the 1 st gear is maximum.

Fig. 6 is a diagram showing an example of changes in creep torque Tc, braking torque Tb, and vehicle speed V with time during creep running in 1 st gear. The difference Δ T between the creep torque Tc and the braking torque Tb is the actual drive torque. As shown in fig. 6, in the 1 st gear, the creep torque Tc is relatively large, and the braking torque Tb is also large. Therefore, at time t1, for example, when the rotational fluctuation of engine 2 occurs, the fluctuation amount of creep torque Tc increases, and creep torque Tc significantly changes (for example, increases). As a result, the vehicle speed V varies greatly, and it becomes difficult to travel at the target vehicle speed in the automatic parking mode, and controllability of the vehicle 100 deteriorates. In view of this, in the present embodiment, in order to improve the controllability of the vehicle 100 in the automatic parking mode, the vehicle control device is configured as follows.

Fig. 7 is a block diagram showing a main configuration of a vehicle control device 70 according to the present embodiment. The vehicle control device 70 is a device for moving the vehicle 100 to the parking lot 111 in the automatic parking mode, and constitutes a part of the vehicle control system 101 of fig. 3. As shown in fig. 7, the vehicle control device 70 mainly includes a controller 60, and a GPS device 54, a camera 51a, a vehicle speed sensor 52a, a throttle actuator 71, a clutch actuator 72, a transmission actuator 73, and a brake actuator 74, which are connected to the controller 60.

The camera 51a captures an image of the periphery of the vehicle 100, and the vehicle speed sensor 52a detects the vehicle speed. The camera 51a constitutes a part of the outer sensor group 51 of fig. 3, and the vehicle speed sensor 52a constitutes a part of the inner sensor group 52. Signals from the camera 51a and the vehicle speed sensor 52a are input to the controller 60 together with a signal from the GPS device 54. The throttle actuator 71, the clutch actuator 72, the transmission actuator 73, and the brake actuator 74 constitute a part of the actuator AC of fig. 3.

The controller 60 has a parking command unit 601, an engine control unit 602, a clutch control unit 603, a transmission control unit 604, and a brake control unit 605 as functional configurations. The parking command unit 601 constitutes a part of the action plan generating unit 65 of fig. 3, for example, and the engine control unit 602, the clutch control unit 603, the transmission control unit 604, and the brake control unit 605 constitute a part of the travel control unit 66 of fig. 3, for example.

The parking command unit 601 instructs the start of the travel in the automatic parking mode (the start of the garage travel) when the vehicle 100 is automatically parked at the target parking position, that is, when the vehicle enters the parking lot 111. The vehicle 100 (controller 60) outputs the command when recognizing a target parking position based on, for example, the positional information of the vehicle 100 acquired by the GPS device 54 and the image signal of the camera 51a capturing the periphery of the vehicle 100. The parking command unit 601 further instructs the start of the travel in the automatic parking mode (the start of the garage exit travel) when detecting a parking state in which the vehicle 100 is parked in the parking lot 111 based on signals from the GPS device 54 and the camera 51a and driving out the vehicle 100 based on the parking state.

When the start of running in the automatic parking mode is instructed by the parking instruction unit 601, the engine control unit 602 outputs a control signal to the throttle actuator 71 so that the engine rotation speed Ne becomes a predetermined idle rotation speed Nei. When the start of running in the automatic parking mode is not instructed, the engine control unit 602 outputs a control signal to the throttle actuator 71 in accordance with the required driving force according to the action plan.

When the parking command unit 601 instructs the start of running in the automatic parking mode, the clutch control unit 603 outputs a control signal to the clutch actuator 72 so that the 1 st clutch C1 is engaged in the half-clutch state and the 2 nd clutch C2 is disengaged, that is, a part of the torque from the engine 2 is input to the transmission 1, and a creep torque can be generated. When the start of the running in the automatic parking mode is not instructed, the clutch control unit 603 outputs a control signal to the clutch actuator 72 in accordance with the required driving force to disengage or engage the clutch C. That is, the clutch C is controlled to be in a connected state or a disconnected state (non-connected state).

When the start of running in the automatic parking mode is instructed by the parking instruction unit 601, the transmission control unit 604 outputs a control signal to the transmission actuator 73 so that the shift position is 3 by driving of the 3-7 shift synchronizing mechanism SY 2. When the start of running in the automatic parking mode is not instructed, the transmission control unit 604 sets a target shift position according to the shift map based on the vehicle speed detected by the vehicle speed sensor 52a and the required driving force, and outputs a control signal to the transmission actuator 73 so that the shift position becomes the target shift position. Therefore, the lowest shift position when the start of running in the automatic parking mode is not instructed is the 1 st shift position, and the transmission 1 shifts gears between the 1 st and 7 th shift positions.

When the start of running in the automatic parking mode is instructed by the parking instruction unit 601, the brake control unit 605 outputs a control signal to the brake actuator 74 so that the vehicle 100 runs at the target vehicle speed by the creep torque, based on the vehicle speed detected by the vehicle speed sensor 52 a. When the start of running in the automatic parking mode is not instructed, the brake control unit 605 outputs a control signal to the brake actuator 74 in accordance with the required driving force.

Fig. 8 is a flowchart showing an example of processing performed by the CPU of the controller 60 of fig. 7 according to a program stored in advance. The processing shown in this flowchart is, for example, to set the parking lot 111 (fig. 4) as the destination of the automated driving mode, to start after the instruction to enable the in-garage driving and the out-garage driving, and to repeat the processing at a predetermined cycle as long as the automated driving mode is continued.

First, at S1 (S: processing step), it is determined whether or not the parking command unit 601 has instructed the automatic parking mode. The automatic parking mode is instructed when the vehicle 100 is driven into the parking lot 111 by creep driving and when the vehicle 100 is driven out of the parking lot 111 by creep driving. Therefore, at S1, it is determined whether the vehicle 100 (controller 60) recognizes the target parking position (at the time of parking in the garage) and whether the vehicle 100 (controller 60) recognizes that the vehicle 100 is parked in the parking lot 111 (at the time of leaving the garage) based on the position information of the vehicle 100 acquired by the GPS device 54 and the image signal of the camera 51 a.

If S1 is affirmative (S1: yes), the routine proceeds to S2, where a control signal is output to the throttle actuator 71 to control the engine speed Ne to a predetermined idle speed Nei. Next, at S3, a control signal is output to the clutch actuator 72 to connect the 1 st clutch C1 in the partially engaged state and to disconnect the 2 nd clutch C2. Next, at S4, a control signal is output to the transmission actuator 73 to switch the shift position to 3. The shift to 3 is performed only during forward travel, and the shift to reverse is performed during reverse travel. Next, at S5, a control signal is output to the brake actuator 74 to adjust the braking force so that the vehicle speed detected by the vehicle speed sensor 52a becomes the target vehicle speed.

On the other hand, if the answer at S1 is negative (no at S1), that is, if the automatic parking mode is not instructed, the routine proceeds to S6, and general control is performed on the engine 2, the clutch C, the transmission 1, and the brake device 4. For example, the control signals are output to the throttle actuator 71 and the clutch actuator 72 in accordance with the driving force demand to control the operations of the engine 2 and the clutch C, and the control signals are output to the transmission actuator 73 in accordance with the vehicle speed and the driving force demand to change the shift position.

Fig. 9 is a diagram showing an example of changes in creep torque Tc, braking torque Tb, and vehicle speed V with time when the automatic parking mode is instructed by vehicle control device 70 according to the present embodiment. In the present embodiment, when the travel in the automatic parking mode is instructed, the transmission 1 is set to 3 th gear, and the vehicle 100 performs creep travel. Therefore, as shown in fig. 9, the creep torque Tc is small and the braking torque Tb is small, as compared with the case where the 1 st gear is set (fig. 5). Therefore, for example, at time t2, the amount of change (e.g., the amount of increase) in creep torque Tc when rotational fluctuation occurs in engine 2 is small, and the amount of vehicle speed fluctuation is small. Therefore, the vehicle 100 can be driven at a stable vehicle speed corresponding to the target vehicle speed, and controllability of the vehicle 100 in the automatic parking mode can be improved.

The present embodiment can provide the following effects.

(1) The vehicle control device 70 controls a running operation of a vehicle 100 including an engine 2 and a transmission 1 that changes a speed of rotation generated by driving of the engine 2 and transmits the changed speed to wheels (fig. 1). The vehicle control device 70 includes: a parking instruction unit 601 that instructs traveling in a parking mode in which the vehicle 100 is driven into or out of the parking lot 111; and a transmission control unit 604 that controls the gear ratio of the transmission 1 (fig. 7). When the parking command unit 601 instructs to perform the travel in the parking mode, the transmission control unit 604 reduces the maximum gear ratio of the transmission 1 during the forward travel relative to the maximum gear ratio during the travel in the parking mode that is not instructed. That is, when the normal running before the running in the parking mode is instructed, the lowest shift position is set to the 1 st shift position, and when the running in the parking mode is instructed, the shift position is switched to the 3 rd shift position.

As a result, the creep torque during parking travel is reduced, and therefore, the amount of change in the vehicle speed due to rotational fluctuation of the engine 2 is reduced, and thus, controllability of the vehicle 100 is improved, and the vehicle 100 can be stably driven at a low target vehicle speed.

(2) The vehicle 100 is configured as an autonomous vehicle having an autonomous driving function (fig. 3). The vehicle control device 70 also has a GPS device 54 and a camera 51a (fig. 7) that recognize a target parking position (parking lot 111) of the vehicle 100. When the target parking position is recognized based on the signals from the GPS device 54 and the camera 51a, the parking command unit 601 instructs the driving in the parking mode (parking driving). Thus, when garage entering is performed in the parking lot 111, the shift position is switched to the 3 rd position, and therefore garage entering driving in which the position of the vehicle 100 needs to be adjusted can be easily achieved.

(3) Further, the vehicle control device 70 detects a state where the vehicle 100 is parked in the parking lot 111 based on signals from the GPS device 54 and the camera 51 a. Then, when a state in which the vehicle 100 is parked in the parking lot 111 is detected, the parking instruction portion 601 instructs to perform traveling in the parking mode (garage exit traveling). Thus, when the vehicle is traveling out of the parking lot 111, the shift range is switched to the 3 rd range, and therefore the vehicle 100 can be easily moved out of the parking lot 111.

(4) The vehicle 100 also has a brake device (brake device) 4 (fig. 1). The vehicle control device 70 further includes: an engine control unit 602 that controls the rotation speed Ne of the engine 2 to a predetermined idle rotation speed Nei so that the vehicle 100 travels with creep torque when the parking command unit 601 instructs the vehicle to travel in the parking mode; and a brake control unit (brake device control unit) 605 that controls the brake device 4 so that the vehicle 100 travels at the target vehicle speed (fig. 7). This allows vehicle 100 to perform automatic parking running with good creep torque while controlling the vehicle speed to the target vehicle speed.

The above embodiments can be modified into various forms. The following describes modifications. In the above embodiment, the creep torque is generated by the clutch C, but if the accuracy of the clutch C is deteriorated, the creep torque and the amount of variation in the vehicle speed become large. In order to avoid this, the automatic parking travel may be started after various characteristics of the clutch C (characteristics such as the temperature and pressure of the clutch operating oil, the clutch stroke, and the clutch torque) are learned in the stopped state. In addition, forced filling may be performed in which the clutch hydraulic pressure is first released into the atmosphere in the stopped state, and then the vehicle is returned to its original state, and after the forced filling, automatic parking travel may be started. In the low temperature state, the idle rotation speed Nei of the engine 2 increases, and there is a possibility that a problem that a creep torque and a variation in vehicle speed become relatively significant arises. Therefore, in the low temperature state, and when the accuracy of the clutch C deteriorates, the automatic parking running can also be prohibited.

In the above embodiment, the target parking position of the vehicle 100 when the garage-in running is performed in the parking mode is recognized based on the signals from the GPS device 54 and the camera 51a, but the target parking position may be recognized based on a signal from a laser radar, a radar, or the like, and the configuration of the parking position recognition unit is not limited to this. In the above embodiment, the state in which the vehicle 100 is parked in the parking space 111 in the parking state when the vehicle is driven for departure in the parking mode is detected based on the signals from the GPS device 54 and the camera 51a, but the configuration of the parking detection unit is not limited to this. That is, if the vehicle is instructed to travel in the parking mode in which the vehicle is driven into or out of the parking lot, the configuration of the parking command unit may be of any form.

In the above embodiment, when the parking command unit 601 instructs to travel in the parking mode, the transmission 1 is switched to the 3 th gear having a gear ratio smaller than the 1 st gear in accordance with a command from the transmission control unit 604, but may be switched to a gear other than the 3 rd gear (for example, 2 nd gear or 4 th gear). That is, if the maximum gear ratio of the transmission is made smaller when the parking command unit instructs to perform the travel in the parking mode than when the travel in the parking mode is not instructed, the configuration of the transmission control unit may be any configuration. In the above embodiment, the step-variable transmission is used as the transmission 1, but a continuously variable transmission may be used, and in this case, when the travel in the parking mode is instructed, the maximum gear ratio of the continuously variable transmission may be made smaller than when the travel in the parking mode is not instructed.

In the above embodiment, the creep torque is generated by setting the clutch C to the half-clutch state, but the creep torque may be generated by using a torque converter instead of the clutch C. In the above embodiment, the vehicle 100 is configured as a hybrid vehicle having the engine 2 and the electric motor 3 as the travel drive sources, but may be a vehicle other than the hybrid vehicle if at least the engine and the transmission are provided.

In the above-described embodiment, the vehicle control device 70 is applied to the autonomous vehicle 100, but the vehicle control device of the present invention can be similarly applied to a vehicle having only a part of the autonomous function, such as a vehicle having a parking assist device. It is also applicable to a vehicle that is parked by manual driving.

The present invention can also be used as a vehicle control method for controlling a running operation of a vehicle 100 including an engine 2 and a transmission 1 that changes a speed of rotation generated by driving of the engine 2 and transmits the changed speed to a drive wheel 47.

One or more of the above embodiments and modifications may be arbitrarily combined, or modifications may be combined with each other.

By adopting the invention, the controllability of the vehicle running action during parking running can be improved.

While the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the disclosure of the following claims.

Claims (7)

1. A vehicle control device for controlling a traveling operation of a vehicle (100) having an engine (2) and a transmission (1) for transmitting a rotational speed generated by driving of the engine (2) to wheels (47), the vehicle control device comprising:

a parking instruction unit (601) that instructs travel in a parking mode in which the vehicle (100) is moved into or out of a parking lot (111); and

a transmission control unit (604) that controls the transmission (1),

when the parking command unit (601) instructs the vehicle to travel in the parking mode, the transmission control unit (604) controls the transmission (1) such that the maximum gear ratio of the transmission (1) is smaller than when the vehicle is not instructed to travel in the parking mode.

2. The vehicle control apparatus according to claim 1,

the vehicle (100) is an autonomous vehicle having an autonomous driving function,

the vehicle control device further has parking position recognition portions (51a, 54), the parking position recognition portions (51a, 54) recognizing a target parking position of the vehicle (100),

when the parking position recognition unit (51a, 54) recognizes a target parking position, the parking command unit (601) instructs to perform travel in a parking mode.

3. The vehicle control apparatus according to claim 1,

the vehicle (100) is an autonomous vehicle having an autonomous driving function,

the vehicle control device further has parking detection units (51a, 54), the parking detection units (51a, 54) detecting a state in which the vehicle (100) is parked in the parking lot (111),

when the state in which the vehicle (100) is parked in the parking lot (111) is detected by the parking detection units (51a, 54), the parking instruction unit (601) instructs to travel in the parking mode.

4. The vehicle control apparatus according to any one of claims 1 to 3,

the vehicle (100) further comprises a braking device (4),

the vehicle control device further includes:

an engine control unit (602) that, when instructed by the parking instruction unit (601) to travel in a parking mode, controls the rotational speed of the engine (1) to a predetermined idle rotational speed (Nei) such that the vehicle (100) travels using creep torque;

and a brake device control unit (605) that controls the brake device (4) so that the vehicle (100) travels at a target vehicle speed.

5. The vehicle control apparatus according to any one of claims 1 to 4,

the vehicle (100) further has a clutch mechanism (C) that transmits or does not transmit torque of the engine (2) to the transmission (1),

the vehicle control device further includes:

and a clutch control unit (603) that controls the clutch mechanism (C) to a half-clutch state when the parking command unit (601) instructs the vehicle to travel in the parking mode, and controls the clutch mechanism (C) to an engaged state or a disengaged state when the parking command unit (601) does not instruct the vehicle to travel in the parking mode.

6. The vehicle control apparatus according to any one of claims 1 to 5,

the transmission (1) is a step-variable transmission,

the transmission control unit (604) controls the transmission (4) such that the lowest gear when travel in the parking mode is not instructed by the parking instruction unit (601) is 1 st gear, and the gear is 2 nd gear, 3 rd gear, or 4 th gear when travel in the parking mode is instructed by the parking instruction unit (601).

7. A vehicle control method for controlling a traveling operation of a vehicle (100) having an engine (2) and a transmission (1) for transmitting a rotational speed generated by driving of the engine (2) to wheels (47), the vehicle control method comprising:

a step of instructing travel in a parking mode in which the vehicle (100) is caused to enter or exit a parking lot (111); and

a step of controlling the transmission (1),

the step of controlling the transmission includes, when the travel in the parking mode is instructed, controlling the transmission (1) such that a maximum gear ratio of the transmission (1) becomes smaller than when the travel in the parking mode is not instructed.

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