JP6604209B2 - Driving assistance device - Google Patents

Description

  The present invention relates to a driving support device for a vehicle.

  2. Description of the Related Art In recent years, driving assistance devices for vehicles are being adopted that perform lane keeping assistance control such as LKA (Lane Keeping Assist) control as driving assistance. In such lane keeping support control, for example, a traveling lane is recognized by a CCD camera, and various types of information such as a curvature radius of the traveling lane, a yaw angle of the vehicle with respect to the traveling lane, an offset amount, and a traveling speed are acquired. Based on this information, the electric motor mounted on the electric power steering system of the vehicle is driven, and the steering angle of the steered wheels is controlled so that the vehicle travels along the target line in the travel lane.

  In Patent Document 1, as driving assistance, when the driver operates the steering wheel during automatic steering control during parking, an assist force is generated in the steering actuator so that the steering torque does not exceed a predetermined value, and driving is performed. A technique for resolving the discomfort of a person is disclosed.

JP-A-11-321686

  By the way, the lane keeping assist control such as LKA control does not always operate when the vehicle travels, but switches between an operating state and a non-operating state, for example, when a driver operates an operation switch. On the other hand, the driver's steering assist by electric power steering is always performed during driving regardless of the operation of the lane keeping assist control. Here, when the driver steers during the operation of the lane keeping assist control, the electric power steering generates the steering assist torque for the driver and the steering torque for returning the vehicle to the target line. Controlled.

  However, in the known technology, the magnitude of the steering assist torque generated by the electric power steering does not take into account the steering torque generated during the operation of the lane keeping assist control. Therefore, when the driver performs steering during the operation of the lane keeping assist control, the driver receives the steering torque for the lane keeping assist control together with the steering assist torque. As a result, there arises a problem that a burden of steering is increased and a sense of discomfort increases.

  The present invention has been made in view of the above, and driving assistance that can suppress the burden and discomfort that the driver feels compared to steering during non-operation when the driver performs steering during operation of lane keeping assistance control An object is to provide an apparatus.

  In order to solve the above-described problems and achieve the object, a driving support apparatus according to an aspect of the present invention includes an electric motor and an electric motor control unit that controls driving of the electric motor according to a given control amount. And a driving support device mounted on a vehicle having a steering mechanism for controlling a steering angle of a steering wheel of the vehicle by driving the electric motor, the steering torque detecting a steering torque input to the steering wheel of the vehicle Assist torque control means for calculating and outputting an assist torque control amount based on detection means, the steering torque, and an assist torque characteristic indicating a relationship between the steering torque and assist torque for assisting driver's steering; A lane maintenance support system that is capable of switching between an operating state and a non-operating state and that causes the vehicle to travel along a target line in a traveling lane in which the vehicle travels. A lane keeping support control means for calculating and outputting an amount; a target control amount computing means for computing a target control amount based on the assist torque control amount and the lane keeping support control amount; and outputting to the motor controller; The assist torque control means outputs different assist torque control amounts for the same steering torque when the lane keeping assist control means is in an operating state and a non-operating state.

In the driving assistance apparatus according to one aspect of the present invention, the assist torque control unit outputs a larger assist torque control amount in the operating state than in the non-operating state with respect to the same steering torque. Features.
Thereby, when the driver performs steering during the operation of the lane keeping assist control, it is possible to suppress a burden felt compared to the steering during the non-operation.

The driving assistance apparatus according to an aspect of the present invention is characterized in that the assist torque characteristic used for calculation is switched between the operating state and the non-operating state.
Thereby, it is possible to appropriately calculate different assist torque control amounts for the operating state and the non-operating state.

The driving support apparatus according to an aspect of the present invention further includes an assist compensation control amount calculation unit that calculates an assist compensation control amount that compensates for the assist torque control amount, and the target control amount calculation unit includes: A target control amount to be output to the motor control unit is calculated based on the assist torque control amount, the lane keeping assist control amount, and the assist compensation control amount.
Thereby, different assist torque control amounts can be calculated while using the same assist torque characteristic in the operating state and the non-operating state.

The driving assistance apparatus according to an aspect of the present invention is characterized in that the assist compensation control amount calculation means sets the assist compensation control amount to zero when the steering torque is a predetermined value or less.
As a result, the possibility that an unintended assist compensation control amount is added due to disturbance or the like is reduced, and the driver can receive a steering assist corresponding to the steering intention.

The driving assistance apparatus according to an aspect of the present invention is characterized in that the assist torque control means is configured to calculate an assist torque control amount corresponding to a characteristic of the lane keeping assistance control amount.
As a result, the driver can receive steering assist in accordance with the characteristics of the lane keeping assist control amount.

  According to the present invention, the assist torque control means outputs different assist torque control amounts depending on whether the lane keeping assist control means is in an operating state or a non-operating state, and the target control amount calculating means is configured to output the assist torque control amount and the lane A target assist torque control amount to be applied to the steering mechanism is calculated based on the maintenance support control amount. As a result, the driver receives different assist torques at the time of steering depending on whether the automatic steering control is in operation or not. Therefore, in the steering at the time of operation of the lane keeping assist control, the steering at the time of non-operation of the automatic steering control is performed. The burden and the sense of incongruity compared to can be suppressed.

It is a schematic block diagram of the vehicle carrying the driving assistance device which concerns on Embodiment 1. FIG. It is a figure explaining lane maintenance support. It is a block diagram of the structural example 1 of an assist torque control part. FIG. 4 is a diagram showing a relationship between a steering angle θ and a steering torque T. 4 is a flowchart illustrating control of an assist torque control unit and an adder of the driving support device according to the first embodiment. It is a block diagram of the structural example 2 of an assist torque control part. It is a figure which shows the relationship between steering torque and a torque characteristic. It is a block diagram of the structural example 3 of an assist torque control part. It is a block diagram of the structural example 4 of an assist torque control part. It is a schematic block diagram of the vehicle carrying the driving assistance device which concerns on Embodiment 2. FIG. It is a block diagram of the structural example of a damping control part. It is a block diagram of the structural example of a torque differential control part. It is a block diagram of the structural example of a hysteresis control part. 6 is a flowchart illustrating control of an assist torque control unit, a damping control unit, a torque differentiation control unit, a hysteresis control unit, and an adder of the driving support device according to the second embodiment. It is a block diagram of the structural example 5 of an assist torque control part. It is a figure which shows an example of the relationship between LK control amount characteristic and assist torque control amount characteristic. It is a figure which shows another example of the relationship between LK control amount characteristic and assist torque control amount characteristic. It is a block diagram of the assist compensation control part at the time of LK control characteristic variable. It is a figure which shows the relationship between steering torque T and assist torque control amount. It is a block diagram of an assist compensation control unit according to the presence or absence of driver steering. 6 is a flowchart illustrating control when an assist torque control unit is replaced in the driving support apparatus according to the second embodiment.

  Embodiments of a driving support apparatus according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In the drawings, the same or corresponding components are appropriately denoted by the same reference numerals, and redundant description is omitted.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a vehicle equipped with a driving support apparatus according to the first embodiment.
The vehicle Ve includes a steering wheel 1, a steering shaft 2, a pinion gear 3, a rack bar 4, an electric motor 5 as an electric motor, a conversion mechanism 6, a pair of tie rods 7L and 7R, and a left steering wheel. A front wheel 8FL and a right front wheel 8FR, an electric motor control unit 9 as an electric motor control unit, a steering torque sensor 10 as a steering torque detection means, and a steering angle sensor 11 are provided. Further, the vehicle Ve includes a camera 21, an image processing unit 22, an LK control unit 23 as a lane keeping support control unit, an LKA switch 24, an assist torque control unit 25 as an assist torque control unit, and a target control amount. An adder 26 as a calculation means and a vehicle speed sensor 27 for detecting the vehicle speed V of the vehicle Ve are provided.

  The LK control unit 23 and the assist torque control unit 25 are each configured by an ECU (Electronic Control Unit). The ECU is physically an electronic circuit mainly composed of a known microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an input / output interface. The functions of the LK control unit 23 and the assist torque control unit 25 are such that an application program held in the ROM of the ECU is loaded into the RAM and executed by the CPU, so that the control target is operated under the control of the CPU. At the same time, it is realized by reading and writing data in RAM and ROM. The LK control unit 23, the assist torque control unit 25, and the adder 26 may be configured by a single ECU.

  The pinion gear 3, the rack bar 4, the electric motor 5, the conversion mechanism 6, the tie rods 7L and 7R, the electric motor control unit 9, and the steering torque sensor 10 are a rack and pinion type electric power steering system 12 as a steering mechanism. Configure. The steering angle sensor 11, the camera 21, the image processing unit 22, the LK control unit 23, the LKA switch 24, the assist torque control unit 25, the adder 26, and the vehicle speed sensor 27 constitute a driving support device 30.

  The pinion gear 3 is connected to the steering wheel 1 via the steering shaft 2 and rotates by the operation of the steering wheel 1. The rack bar 4 is connected to the pinion gear 3 and is slid in the axial direction by the rotation of the pinion gear 3. The tie rods 7L and 7R connect the rack bar 4 to the front wheels 8FL and 8FR, respectively, and transmit the displacement of the rack bar 4 to the front wheels 8FL and 8FR to change the steering angle of the front wheels 8FL and 8FR. The electric motor 5 slides and displaces the rack bar 4 in the axial direction via the conversion mechanism 6. As the conversion mechanism 6, for example, a ball screw type is adopted. The electric motor control unit 9 controls the drive of the electric motor 5 to slide the rack bar 4 to change the steering angle of the left and right front wheels 8FL and 8FR. The steering torque sensor 10 and the steering angle sensor 11 are provided on the steering shaft 2, and detect the steering torque and the steering angle of the steering wheel 1, respectively.

  When the driver turns the steering wheel 1, the pinion gear 3 rotates and the rack bar 4 slides in the axial direction. Then, the tie rods 7L and 7R are displaced in conjunction with the rack bar 4, and the steering angles of the left and right front wheels 8FL and 8FR are changed. At this time, when the electric motor 5 is driven by the electric motor control unit 9 of the electric power steering system 12, the rotational torque of the electric motor 5 is transmitted to the rack bar 4 via the conversion mechanism 6. As a result, the steering operation of the left and right front wheels 8FL, 8FR by the driver is assisted by the rotational torque of the electric motor 5, and the driver's steering burden is reduced. The assistance by the electric motor 5 will be described in detail later.

  The camera 21 is a CCD camera, for example. The camera 21 is for photographing the white line of the traveling lane of the vehicle Ve, and two cameras 21 are attached to the front surface of the vehicle Ve in the first embodiment, but the number and position of the cameras are not particularly limited. The camera 21 captures the surrounding situation in front of the vehicle Ve and transmits the image data to the image processing unit 22.

  The image processing unit 22 performs image processing on the image data transmitted from the camera 21 and performs known edge processing and pattern matching on the image data, thereby recognizing a white line that defines a travel lane on which the vehicle Ve travels. The travel lane in which the vehicle Ve travels is detected based on the recognized white line. Further, the image processing unit 22 calculates the radius of curvature of the traveling lane, the offset amount of the vehicle Ve with respect to the traveling lane (the lateral deviation of the center line of the vehicle with respect to the center line of the traveling lane), and the yaw angle based on the detected traveling lane. Detect by calculation. The image processing unit 22 transmits these detection results to the LK control unit 23.

  The LK control unit 23 drives the electric motor 5 by the electric motor control unit 9 and executes lane keeping support control, that is, LK control, for causing the vehicle Ve to travel along the traveling lane. In the LK control, after calculating a target angle, a lane keeping assist torque (hereinafter sometimes referred to as LK torque) is generated in the electric motor 5, and the vehicle Ve is defined by a white line WL as shown in FIG. The steering operation is supported so as to travel along the target line TL near the center in the travel lane DL. Specifically, the LK control unit 23 calculates a target angle based on the detected curvature radius, offset amount, yaw angle, and the like, and supplies the lane keeping assist torque necessary for realizing the target angle to the electric motor 5. A control amount (lane maintenance support control amount, hereinafter sometimes referred to as LK control amount) to be given to the electric motor control unit 9 is generated and output to the adder 26.

  The calculation of the LK control amount is performed as follows, for example. The LK control unit 23 calculates a lateral acceleration necessary for causing the vehicle Ve to travel along the target line TL based on the detected radius of curvature of the travel lane DL. Further, the LK control unit 23 calculates the lateral acceleration necessary for converging the offset amount to the target offset amount by feedback control based on the deviation between the detected offset amount and the preset target offset amount stored in advance. To do. Further, the LK control unit 23 calculates the lateral acceleration necessary for converging the yaw angle to the target yaw angle by feedback control based on the deviation between the detected yaw angle and the preset and stored target yaw angle. To do. Next, the target lateral acceleration is calculated by adding these three calculated lateral accelerations, and the target angle necessary for generating the target lateral acceleration in the vehicle Ve is calculated, and then the lane keeping assist torque is calculated. calculate. Then, an LK control amount to be given to the electric motor control unit 9 in order to cause the electric motor 5 to generate the calculated lane keeping assist torque is calculated.

  The LKA switch 24 is a switch for selecting ON / OFF of LKA control, and is connected to the LK control unit 23. The LKA switch 24 is installed in the driver seat of the vehicle Ve. By switching ON / OFF of the LKA switch 24, it is possible to switch between an operating state (a state in which LK control is executed) and a non-operating state (a state in which LK control is not executed) of the vehicle Ve. The LK control unit 23 outputs a flag indicating whether or not the LK control is being executed to the assist torque control unit 25. Hereinafter, the case where the LK control unit 23 is in the operating state may be referred to as the normal time when the LK control unit 23 is in the LK control and the non-operating state. The LK controlling flag is “1” during LK control and “0” during normal operation. The LK control amount output from the LK control unit 23 at normal time is zero.

  The assist torque control unit 25 drives the electric motor 5 by the electric motor control unit 9 to assist the driver's steering and generates control torque (assist torque control) for reducing the driver's steering burden. Execute. As shown in the block diagram of Structural Example 1 in FIG. 3, the assist torque control unit 25 includes an LK determination unit 25a and an assist torque control amount calculation unit 25b.

  The LK discriminating unit 25 a receives an input of the LK controlling flag output from the LK control unit 23. When the LK controlling flag is “0”, the LK determination unit 25a outputs a signal to the assist torque control amount calculation unit 25b indicating that the LK control unit 23 is in a non-operating state and normal. In addition, when the LK control flag is “1”, the LK determination unit 25a outputs a signal indicating that the LK control unit 23 is performing LK control to the assist torque control amount calculation unit 25b.

  The assist torque control amount calculation unit 25b stores an assist characteristic map as an assist torque characteristic indicating a relationship between the steering torque T and an assist torque value generated with respect to the steering torque T. The assist torque control amount calculation unit 25b stores a plurality of assist characteristic maps corresponding to the vehicle speed V. The assist torque control amount calculation unit 25b obtains the assist torque to be generated based on the vehicle speed V, the steering torque T, and the assist characteristic map, and applies the assist torque to the electric motor control unit 9 in order to cause the electric motor 5 to generate the assist torque. A control amount (assist torque control amount) is calculated and output to the adder 26.

  Here, the assist torque control amount calculation unit 25b changes the assist torque characteristic map used for calculating the assist torque control amount depending on whether the LK control unit 23 is in the operating state or the non-operating state. Specifically, as shown in FIG. 3, when a signal indicating normal time is input from the LK discriminating unit 25a, the assist torque control amount calculation unit 25b, as an assist torque characteristic map at normal time, The assist torque control amount is calculated and output using an assist torque characteristic map in which the assist torque value with respect to the steering torque T has a relationship indicated by a broken line. On the other hand, when a signal indicating that LK control is being performed is input from the LK determination unit 25a, the assist torque control amount calculation unit 25b has an assist torque value for the steering torque T as an assist torque characteristic map during LK control. An assist torque control amount is calculated and output using an assist torque characteristic map having a relationship indicated by a solid line. As shown by arrows in FIG. 3, the assist torque characteristic used for calculation during LK control has a characteristic that the assist torque value for the same steering torque is larger than the assist torque characteristic used for calculation in the non-operating state. As a result, the assist torque control unit 25 outputs different assist torque control amounts for the same steering torque during LK control and during normal operation.

  Returning to FIG. 1, the description will be continued. During the LK control, the adder 26 adds the LK control amount output from the LK control unit 23 and the assist torque control amount output from the assist torque control unit 25, and uses this as the target assist torque control amount. Output to the control unit 9. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque of the electric motor 5 (the torque including the lane keeping assist torque and the assist torque) is transmitted to the rack bar 4 through the conversion mechanism 6. As a result, both LK control and driver assistance are performed.

  In addition, during normal times, the adder 26 outputs the assist torque control amount output from the assist torque control unit 25 to the electric motor control unit 9 as a target assist torque control amount. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque (assist torque) of the electric motor 5 is transmitted to the rack bar 4 via the conversion mechanism 6. As a result, the driver assists the steering.

  In the driving support device 30 according to the first embodiment, the assist torque control amount calculation unit 25b calculates the assist torque control amount when the LK control unit 23 is in an operating state (during LK control) and a non-operating state (normal time). Further, the assist torque characteristic used for calculation during the LK control has a characteristic that the assist torque value is larger for the same steering torque T than the assist torque characteristic used for calculation during normal operation. Have. As a result, during LK control, the driver receives higher assist torque with respect to the steering operation, so that the steering burden and discomfort felt by the driver during LK control compared to the normal time are suppressed.

  FIG. 4 is a diagram showing the relationship between the steering angle θ and the steering torque T realized in the vehicle Ve. The dotted line indicates the characteristic when the assist torque control amount is calculated using the normal assist torque characteristic map at the normal time, and the solid line indicates the assist torque control using the assist torque characteristic during the LK control during the LK control. The characteristic when the quantity is calculated is shown. As a comparative example, the broken line indicates the characteristic when the assist torque control amount is calculated using the normal assist torque characteristic map during the LK control. As shown in FIG. 4, the solid line characteristic approaches the dotted line characteristic from the broken line characteristic as indicated by an arrow. This means that during the LK control, the assist torque control amount is calculated using the assist torque characteristic during the LK control, so that the driver can use the assist torque characteristic map during normal times to assist the assist torque control. This means that a steering assist close to that when the amount is calculated is received. This indicates that the driver can perform steering with a feeling close to that of normal steering even during the LK control, and the burden and discomfort are suppressed.

  FIG. 5 is a flowchart showing the control of the assist torque control unit 25 and the adder 26 of the driving support device 30. First, in step S <b> 101, the assist torque control unit 25 receives input of the vehicle speed V of the vehicle Ve detected by the vehicle speed sensor 27 and the steering torque T detected by the steering torque sensor 10. Subsequently, in step S <b> 102, the LK determination unit 25 a of the assist torque control unit 25 receives an input of the LK controlling flag output from the LK control unit 23. Subsequently, in step S103, the LK determination unit 25a determines whether or not LK control is being performed based on the LK control flag. When it is determined that the LK control is being performed (step S103, Yes), the control proceeds to step S104.

  In step S104, the assist torque control amount calculation unit 25b selects an assist torque characteristic map during LK control, calculates an assist torque control amount using the map, and proceeds to step S106.

  On the other hand, if it is determined in step S103 that the LK control is not being performed (No in step S103), the control proceeds to step S105. In step S105, the assist torque control amount calculation unit 25b selects an assist torque characteristic map in a normal state, uses this to calculate an assist torque control amount, and the control proceeds to step S106. In step S106, the adder 26 adds the LK control amount output from the LK control unit 23 and the assist torque control amount output from the assist torque control unit 25, and uses this as the target assist torque control amount. The result is output to the control unit 9, and this control flow returns.

  As described above, according to the driving support device 30 according to the first embodiment, it is possible to suppress a burden and a sense of incongruity that are felt in the steering during the LK control as compared with the normal steering.

(Configuration example 2 of assist torque control unit)
Next, a configuration example of an assist torque control unit that can be replaced with the assist torque control unit 25 in the driving support device 30 according to the first embodiment will be described. FIG. 6 is a block diagram of Configuration Example 2 of the assist torque control unit. The assist torque control unit 25A shown in FIG. 6 includes an assist compensation control amount calculation unit 25Aa as an assist compensation control amount calculation unit, a switch unit 25Ab, an assist torque control amount calculation unit 25Ac, and an adder 25Ad. .

  The assist compensation control amount computing unit 25Aa computes an assist compensation control amount that is added to compensate for the assist torque control amount during LK control. The assist compensation control amount calculation unit 25Aa stores an assist compensation characteristic map as an assist compensation characteristic indicating a relationship between the steering torque T and an assist compensation amount (torque) generated with respect to the steering torque T. Specifically, in the assist compensation characteristic map, the assist compensation amount is zero when the value of the steering torque T is from 0 to a predetermined value T1, and a dead zone is provided. Note that the dead zone is not necessarily provided. Further, the assist compensation amount increases from the value T1 as the steering torque T increases. When the assist compensation amount reaches the maximum value MAX at the value T2, the assist compensation amount thereafter takes a constant value MAX regardless of the value of the steering torque T. As the assist compensation characteristic map, a plurality of assist compensation characteristic maps corresponding to the vehicle speed V are stored, and the value MAX in the corresponding assist compensation characteristic map increases as the vehicle speed V increases.

  The assist compensation control amount calculating unit 25Aa calculates an assist compensation control amount based on the vehicle speed V, the steering torque T, and the assist compensation characteristic map, and outputs the calculated amount to the switch unit 25Ab.

  The switch unit 25Ab accepts the input of the LK controlling flag output from the LK control unit 23. The switch unit 25Ab is turned off when the LK control flag is “0”, and does not output the assist compensation control amount input from the assist compensation control amount calculation unit 25Aa. On the other hand, when the LK control in-progress flag is “1”, the switch unit 25Ab is turned on, and outputs the assist compensation control amount input from the assist compensation control amount calculation unit 25Aa to the adder 25Ad.

  The assist torque control amount calculation unit 25Ac stores an assist torque characteristic map as an assist torque characteristic indicating a relationship between the steering torque T and an assist torque value generated with respect to the steering torque T. The assist torque control amount calculation unit 25Ac stores a plurality of assist torque characteristic maps corresponding to the vehicle speed V. FIG. 6 schematically shows an assist torque characteristic map corresponding to each of a plurality of vehicle speeds as one map, and the assist torque value in the corresponding assist torque characteristic map increases as the vehicle speed increases with respect to the same steering torque. It is small. The assist torque control amount calculation unit 25Ac calculates an assist torque control amount (here, referred to as pre-compensation assist torque control amount) based on the vehicle speed V, the steering torque T, and the assist torque characteristic map, and sends it to the adder 25Ad. Output.

  During the LK control, the adder 25Ad adds the assist compensation control amount output from the switch unit 25Ab and the pre-compensation assist torque control amount output from the assist torque control amount calculation unit 25Ac, and adds this to the assist torque control amount. Is output to the adder 26 (see FIG. 1). Further, in normal times, the adder 25Ad outputs the pre-compensation assist torque control amount output from the assist torque control amount calculation unit 25Ac to the adder 26 as an assist torque control amount.

  During the LK control, the adder 26 adds the LK control amount output from the LK control unit 23 and the assist torque control amount output from the assist torque control unit 25, and uses this as the target assist torque control amount. Output to the control unit 9. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque of the electric motor 5 (the torque including the lane keeping assist torque and the assist torque) is transmitted to the rack bar 4 through the conversion mechanism 6. As a result, both LK control and driver assistance are performed.

  In addition, during normal times, the adder 26 outputs the assist torque control amount output from the assist torque control unit 25 to the electric motor control unit 9 as a target assist torque control amount. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque (assist torque) of the electric motor 5 is transmitted to the rack bar 4 via the conversion mechanism 6. As a result, the driver assists the steering.

  When the assist torque control unit 25A is used, while the LK control unit 23 is performing LK control, the adder 26 outputs to the electric motor control unit 9 based on the assist torque control amount, the LK control amount, and the assist compensation control amount. Calculate the control amount. Specifically, the assist compensation control amount and the pre-compensation assist torque control amount are added, and this is used as the assist torque control amount to calculate the target assist torque control amount. On the other hand, at the normal time, the target assist torque control amount is calculated using the pre-compensation assist torque control amount as the assist torque control amount. Thus, during LK control, the driver receives an assist torque that is higher by an amount corresponding to the assist compensation control amount with respect to the steering operation. Discomfort is suppressed. In particular, the assist compensation characteristic used when the assist compensation control amount calculation unit 25Aa calculates the assist compensation control amount is set to a characteristic that cancels the influence of the LK torque based on the LK control amount on the steering of the driver. This is preferable because the driver's steering burden and discomfort are further suppressed.

  FIG. 7 is a diagram showing the relationship between the steering torque, the LK torque characteristic, the normal assist torque characteristic, and the assist torque characteristic that has been assist-compensated by adding the assist compensation control amount. In the torque value on the vertical axis, the positive direction indicates the direction of the torque for turning the steering wheel of the vehicle in the left direction with respect to the traveling direction, and the negative direction turns the steering wheel in the right direction. Indicates the direction. Here, the characteristics in the positive direction will be described, and the description of the characteristics in the negative direction will be omitted. In FIG. 7, LK torque is generated so that if the driver steers leftward during straight traveling, the steered wheels steer rightward. When the driver receives the assist torque according to the normal assist torque characteristic and steers leftward, there is a steering burden or a sense of incongruity due to the influence of the LK torque. On the other hand, when the driver receives the assist torque according to the assist torque characteristic compensated for assist by adding the compensation control amount and steers leftward, the effect of the LK torque on the driver's steering is canceled by the assist compensation. Therefore, the driver's steering burden and uncomfortable feeling are suitably suppressed. At this time, the assist torque characteristic is bent at a bending point P2 with respect to the bending point P1 of the LK torque characteristic, and on the side where the steering torque is larger than the bending point P2, the maximum value of the absolute value of the LK torque characteristic is set to the normal assist torque characteristic ( It is a characteristic with a certain value added.

  Further, when the assist torque control unit 25A is used, the driving support device uses the same assist torque characteristic map for the assist torque control amount calculation unit 25Ac during the LK control and during the normal time, and the assist torque control amount (assist before assist). Even if the torque control amount is calculated, it is possible to provide the driver with a higher steering assist by the amount of the assist compensation control amount during the LK control. Thereby, since the assist torque characteristic map which should be memorize | stored in 25 A of assist torque control parts can be reduced, the memory capacity which 25 A of assist torque control parts should have can be reduced.

  Further, when the assist torque control unit 25A is used, the assist compensation control amount calculation unit 25Aa sets the assist compensation control amount to zero when the steering torque is equal to or less than a predetermined value, so a dead zone is provided for the steering torque. The possibility that an assist compensation control amount not intended by the driver is added due to generation of steering torque not intended by the driver, such as a disturbance, is reduced. As a result, the driver can receive a steering assist corresponding to the steering intention.

(Configuration example 3 of assist torque control unit)
FIG. 8 is a block diagram of Configuration Example 3 of the assist torque control unit. The assist torque control unit 25B illustrated in FIG. 8 includes assist torque control amount calculation units 25Ba and 25Bb and a switch unit 25Bc.

  The assist torque control amount calculation unit 25Ba stores an assist torque characteristic map 1 used during LK control as an assist torque characteristic indicating a relationship between the steering torque T and an assist torque value generated with respect to the steering torque T. Yes. The assist torque control amount calculation unit 25Ba stores a plurality of assist torque characteristic maps 1 corresponding to the vehicle speed V. Here, the assist torque characteristic map 1 has characteristics set so as to suppress a driver's burden and discomfort caused during steering during LK control. The assist torque control amount calculation unit 25Ba calculates an assist torque control amount during the LK control based on the vehicle speed V, the steering torque T, and the assist torque characteristic map 1, and outputs it to the switch unit 25Bc.

  The assist torque control amount calculation unit 25Bb stores an assist torque characteristic map 2 that is normally used. The assist torque control amount calculation unit 25Bb stores a plurality of assist torque characteristic maps 2 corresponding to the vehicle speed V. As apparent from comparing the assist torque characteristic map 1 and the assist torque characteristic map 2 in FIG. 8, the assist torque characteristic map 1 is a characteristic having a larger assist torque value with respect to the same steering torque value. Yes. The assist torque control amount calculation unit 25Bb calculates the normal assist torque control amount based on the vehicle speed V, the steering torque T, and the assist torque characteristic map 2, and outputs it to the switch unit 25Bc.

  The switch unit 25Bc receives an input of the LK controlling flag output from the LK control unit 23 and an input of the assist torque control amount output from each of the assist torque control amount calculation units 25Ba and 25Bb. When the LK controlling flag is “1”, the switch unit 25Bc outputs the assist torque control amount input from the assist torque control amount calculating unit 25Ba to the adder 26 (see FIG. 1), and the LK controlling flag is set. When it is “0”, the assist torque control amount input from the assist torque control amount calculation unit 25Bb is output to the adder 26. FIG. 8 shows a state in which the LK control in-progress flag is “1” and the switch unit 25Bc is operating so as to output the assist torque control amount input from the assist torque control amount calculation unit 25Ba. Yes.

  During the LK control, the adder 26 adds the LK control amount output from the LK control unit 23 and the assist torque control amount during the LK control output from the assist torque control unit 25B, and adds this to the target assist torque. It outputs to the electric motor control part 9 as a controlled variable. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque of the electric motor 5 (the torque including the lane keeping assist torque and the assist torque) is transmitted to the rack bar 4 through the conversion mechanism 6. As a result, both LK control and driver assistance are performed.

  In addition, during normal times, the adder 26 outputs the normal assist torque control amount output from the assist torque control unit 25B to the electric motor control unit 9 as a target assist torque control amount. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque (assist torque) of the electric motor 5 is transmitted to the rack bar 4 via the conversion mechanism 6. As a result, the driver assists the steering.

  The assist torque control unit 25B switches the assist torque characteristic map used for calculating the assist torque control amount between the LK control and the normal time. As a result, different assist torque control amounts can be appropriately calculated for the operating state and the non-operating state, and the burden and discomfort felt by the driver in steering during LK control compared to normal steering can be suppressed.

(Configuration example 4 of assist torque control unit)
FIG. 9 is a block diagram of Configuration Example 4 of the assist torque control unit. The assist torque control unit 25C illustrated in FIG. 9 includes an assist torque control amount calculation unit 25Ca, a proportional unit 25Cb, a constant generator 25Cc, an adder 25Cd, and a multiplier 25Ce.

  The assist torque control amount calculation unit 25Ca stores an assist torque characteristic map as an assist torque characteristic indicating a relationship between the steering torque T and an assist torque value generated with respect to the steering torque T. The assist torque control amount calculation unit 25Ca stores a plurality of assist torque characteristic maps corresponding to the vehicle speed V. The assist torque control amount calculation unit 25Ca calculates an assist torque control amount based on the vehicle speed V, the steering torque T, and the assist torque characteristic map, and outputs the assist torque control amount to the multiplier 25Ce.

  The proportional device 25 </ b> Cb receives the input of the LK controlling flag output from the LK control unit 23. When the LK control flag is “0”, the proportional unit 25Cb outputs 0 as a gain to the adder 25Cd. When the LK control flag is “1”, the proportional unit 25Cb adds a positive constant K as the gain to the adder 25Cd. Output to.

The constant generator 25Cc outputs the constant 1 to the adder 25Cd.
The adder 25Cd outputs a value obtained by adding the gain input from the proportional unit 25Cb and the constant 1 input from the constant generator 25Cc to the multiplier 25Ce. That is, the adder 25Cd outputs a value (1 + K) during LK control, and outputs a value 1 during normal operation.

  The multiplier 25Ce multiplies the value output from the adder 25Cd by the assist torque control amount output from the assist torque control amount calculation unit 25Ca, and outputs this to the adder 26 (see FIG. 1) as the assist torque control amount. To do. That is, the multiplier 25Ce multiplies the assist torque control amount output from the assist torque control amount calculation unit 25Ca during the LK control by (1 + K), and outputs this as an assist torque control amount. The assist torque control amount output from the control amount calculation unit 25Ca is directly output as the assist torque control amount.

  During the LK control, the adder 26 adds the LK control amount output from the LK control unit 23 and the assist torque control amount output from the assist torque control unit 25C, and uses this as the target assist torque control amount. Output to the control unit 9. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque of the electric motor 5 (the torque including the lane keeping assist torque and the assist torque) is transmitted to the rack bar 4 through the conversion mechanism 6. As a result, both LK control and driver assistance are performed.

  Further, during normal times, the adder 26 outputs the assist torque control amount output from the assist torque control unit 25C to the electric motor control unit 9 as a target assist torque control amount. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque (assist torque) of the electric motor 5 is transmitted to the rack bar 4 via the conversion mechanism 6. As a result, the driver assists the steering.

  During the LK control, the assist torque control unit 25C outputs an assist torque control amount that is (1 + K) times the normal time as the assist torque control amount. As a result, the driver receives a higher steering assist than during normal operation during LK control, so that the burden and discomfort felt during steering during LK control compared to normal operation can be suppressed. Note that the value of the constant K is set in advance to a value (for example, a value in the range of 0.5 to 4) that can suppress the driver's burden and discomfort caused during steering during LK control.

  In addition, when the assist torque control unit 25C is used, the driving assist device calculates the assist torque control amount using the same assist torque characteristic map by the assist torque control amount calculation unit 25Ca during LK control and during normal operation. In addition, higher steering assist can be provided to the driver during the LK control. Thereby, since the assist torque characteristic map which should be memorize | stored in 25 C of assist torque control parts can be reduced, the memory capacity which 25 C of assist torque control parts should have can be reduced.

(Embodiment 2)
FIG. 10 is a schematic configuration diagram of a vehicle equipped with the driving support apparatus according to the second embodiment.
Since the vehicle Ve is different from the vehicle Ve shown in FIG. 1 only in the configuration of the driving support device, the driving support device 30A according to the second embodiment will be described below, and redundant description will be omitted.

  The driving support device 30A has a configuration in which a damping control unit 31, a torque differentiation control unit 32, and a hysteresis control unit 33, each configured by an ECU, are added to the configuration of the driving support device 30 shown in FIG. The assist torque control unit 25, the damping control unit 31, the torque differentiation control unit 32, the hysteresis control unit 33, and the adder 26 may be configured by a single ECU. Part 23 may be included.

  The LK control unit 23 outputs to the assist torque control unit 25, the damping control unit 31, the torque differentiation control unit 32, and the hysteresis control unit 33 a flag indicating that the LK control is being performed or is normal.

  The damping control unit 31 drives the electric motor 5 by the electric motor control unit 9 and executes control (damping torque control) for generating a damping torque for improving the convergence of the steering. As shown in FIG. 11, the damping control unit 31 includes an LK determination unit 31a and a damping correction amount calculation unit 31b.

  The LK discriminating unit 31 a receives an input of the LK controlling flag output from the LK control unit 23. When the LK controlling flag is “0”, the LK determination unit 31a outputs a signal indicating that the LK control unit 23 is in a non-operating state and is in a normal state to the damping correction amount calculation unit 31b. When the LK control flag is “1”, the LK determination unit 31a outputs a signal indicating that the LK control unit 23 is performing LK control to the damping correction amount calculation unit 31b.

  The damping correction amount calculation unit 31b is a steering angular velocity θ ′ input by the driver through the steering wheel 1 and a damping torque (hereinafter, sometimes referred to as a damping correction amount) generated with respect to the steering angular velocity θ ′. A damping correction amount map showing the relationship is stored. The damping correction amount calculation unit 31b stores a plurality of damping correction amount maps corresponding to the vehicle speed V. A vehicle speed V and a steering angular velocity θ ′ are input to the damping control unit 31. As the steering angular velocity θ ′, one calculated from the steering angle θ detected by the steering angle sensor 11 can be used. The damping correction amount calculation unit 31b obtains a damping correction amount to be generated based on the vehicle speed V, the steering angular velocity θ ′, and the damping correction amount map, and the electric motor control unit generates the damping correction amount in the electric motor 5. 9 is calculated and output to the adder 26.

As shown in FIG. 11, in the damping correction amount map, the damping correction amount is zero from the value of the steering angular velocity θ ′ to a predetermined positive value + θ ₀ ′, and the value of the steering angular velocity θ ′ is + θ ₀ ′. In a larger range, the damping correction amount is set to decrease (the absolute value increases) as the steering angular velocity θ ′ increases.

  Here, the damping correction amount calculation unit 31b changes the damping correction amount map used for calculating the damping control amount depending on whether the LK control unit 23 is in the operating state or the non-operating state. Specifically, as shown in FIG. 11, when a signal indicating normal time is input from the LK determination unit 32a, the damping correction amount calculation unit 31b uses a normal damping correction amount map. Calculates and outputs the damping control amount. At this time, the normal damping correction amount map has a characteristic in which the damping correction amount with respect to the steering angular velocity θ ′ has a relationship indicated by a broken line in FIG. On the other hand, when a signal indicating that LK control is being performed is input from the LK determination unit 32a, the damping correction amount calculation unit 31b calculates and outputs a damping control amount using a damping correction amount map during LK control. . At this time, the damping correction amount map during LK control has a characteristic in which the damping correction amount with respect to the steering angular velocity θ ′ has a relationship indicated by a solid line in FIG. As shown by an arrow in FIG. 11, the damping correction amount in the map under LK control has a smaller value (the absolute value is large) for the same steering angular velocity θ ′ than the damping correction amount in the normal map.

  The torque differential control unit 32 executes control (torque differential control) for driving the electric motor 5 by the electric motor control unit 9 to generate torque for reducing fluctuations in steering torque. As shown in FIG. 12, the torque differential control unit 32 includes an LK determination unit 32 a and a torque differential correction amount calculation unit 32 b.

  The LK discriminating unit 32 a receives an input of the LK controlling flag output from the LK control unit 23. When the LK control flag is “0”, the LK determination unit 32a outputs a signal to the torque differential correction amount calculation unit 32b indicating that the LK control unit 23 is in a non-operating state and normal. Further, when the LK control flag is “1”, the LK determination unit 32a outputs a signal indicating that the LK control unit 23 is performing LK control to the torque differential correction amount calculation unit 32b.

  The torque differential correction amount calculation unit 32b stores a torque differential correction amount map as a characteristic indicating the relationship between the differential value T ′ of the steering torque T and the torque differential correction amount generated with respect to the torque differential value T ′. Yes. The torque differential correction amount calculation unit 32b stores a plurality of torque differential correction amount maps corresponding to the vehicle speed V. The vehicle speed V and the steering torque T are input to the torque differential control unit 32. The torque differential value T ′ can be calculated from the input steering torque T by the torque differential control unit 32. The torque differential correction amount calculation unit 32b obtains the torque differential correction amount to be generated based on the vehicle speed V, the torque differential value T ′, and the torque differential correction amount map, and causes the electric motor 5 to generate this torque differential correction amount. The control amount (torque differential control amount) given to the electric motor controller 9 is calculated and output to the adder 26.

As shown in FIG. 12, in the torque differential correction amount map, the torque differential correction amount is zero when the value of the torque differential value T ′ is zero to a predetermined positive value + T ₀ ′, and the value of the torque differential value T ′. Is greater than + T ₀ ′, the torque differential correction amount is set to increase as the torque differential value T ′ increases.

  Here, the torque differential correction amount calculation unit 32b changes the torque differential correction amount map used for calculating the torque differential control amount depending on whether the LK control unit 23 is in the operating state or the non-operating state. Specifically, as shown in FIG. 12, when a signal indicating normal time is input from the LK discrimination unit 32a, the torque differential correction amount calculation unit 32b displays a normal torque differential correction amount map. Used to calculate and output the torque differential control amount. At this time, the normal torque differential correction amount map has a characteristic in which the torque differential correction amount with respect to the torque differential value T ′ has a relationship indicated by a broken line in FIG. 12. On the other hand, when a signal indicating that LK control is being performed is input from the LK determination unit 32a, the torque differential correction amount calculation unit 32b calculates a torque differential control amount using a torque differential correction amount map during LK control. ,Output. At this time, the torque differential correction amount map during the LK control has a characteristic that the torque differential correction amount with respect to the torque differential value T ′ has a relationship indicated by a solid line in FIG. 12. As shown by an arrow in FIG. 12, the torque differential correction amount in the map during LK control has a smaller value for the same torque differential value T ′ than the torque differential correction amount in the normal map.

  The hysteresis control unit 33 drives the electric motor 5 by the electric motor control unit 9 to generate a torque that acts like a frictional force with respect to the driver's steering in a direction opposite to the steering direction of the driver. Executes control to stabilize (his control). As shown in FIG. 13, the hiss control unit 33 includes an LK discriminating unit 33 a and a hiss control amount calculation unit 33 b.

  The LK discriminating unit 33a accepts the input of the LK controlling flag output from the LK control unit 23. When the LK control flag is “0”, the LK determination unit 33a outputs a signal to the hiss control amount calculation unit 33b indicating that the LK control unit 23 is in a non-operating state and normal. When the LK control flag is “1”, the LK determination unit 33a outputs a signal indicating that the LK control unit 23 is performing LK control to the hysteresis control amount calculation unit 33b.

  The hysteresis control amount calculation unit 33b stores a hysteresis control amount map as a characteristic indicating the relationship between the steering angle change amount and the hysteresis control amount generated with respect to the steering angle change amount. The hysteresis control amount calculation unit 33b stores a plurality of hysteresis control amount maps corresponding to the vehicle speed V. The hysteresis control unit 33 receives the vehicle speed V, the steering torque T, and the steering angle θ. Note that the steering angle change amount can be calculated by the hysteresis control unit 33 from the input steering angle θ. The hysteresis control amount calculation unit 33 b calculates a hysteresis control amount to be given to the electric motor control unit 9 based on the vehicle speed V, the steering angle change amount, and the hysteresis control amount map, and outputs the calculation result to the adder 26.

  As shown in FIG. 13, in the hysteresis control amount map, the hysteresis control amount increases as the steering angle change amount increases from zero, and is set to be a constant value above a predetermined steering angle change amount.

  Here, the hysteresis control amount calculation unit 33b changes the hysteresis control amount map used for calculating the hysteresis control amount depending on whether the LK control unit 23 is in the operating state or the non-operating state. Specifically, as shown in FIG. 13, when a signal indicating normal time is input from the LK determination unit 33a, the hiss control amount calculation unit 33b uses a normal his control amount map. Calculate and output the hysteresis control amount. At this time, the normal hysteresis control amount map has a characteristic in which the hysteresis control amount with respect to the steering angle change amount has a relationship indicated by a broken line in FIG. On the other hand, when a signal indicating that the LK control is being performed is input from the LK discriminating unit 33a, the hiss control amount calculating unit 33b calculates the hiss control amount using the hiss control amount map during the LK control, and outputs it. To do. At this time, the hysteresis control amount map during LK control has a characteristic in which the hysteresis control amount with respect to the steering angle change amount has a relationship indicated by a solid line in FIG. As shown by an arrow in FIG. 13, the hysteresis control amount in the map under LK control has a constant steering angle change amount that is a constant value and a constant value that is larger than the hysteresis control amount in the map at the normal time.

  Returning to FIG. During the LK control, the adder 26 outputs the LK control amount output from the LK control unit 23, the assist torque control amount during LK control output from the assist torque control unit 25, and the LK output from the damping control unit 31. The damping control amount under control, the torque differential control amount during LK control output from the torque differential control unit 32, and the hysteresis control amount during LK control output from the hiss control unit 33 are added, and this is set as the target. It outputs to the electric motor control part 9 as an assist torque control amount. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque of the electric motor 5 (the torque including the lane keeping assist torque and the assist torque) is transmitted to the rack bar 4 through the conversion mechanism 6. As a result, both LK control and driver assistance are performed.

  Further, in the normal time, the adder 26 adds the normal assist torque control amount, the normal damping control amount, the normal torque differential control amount, and the normal his control amount. It outputs to the electric motor control part 9 as a target assist torque control amount. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. Thereby, the rotational torque (assist torque) of the electric motor 5 is transmitted to the rack bar 4 via the conversion mechanism 6. As a result, the driver assists the steering.

  In the driving support device 30A according to the second embodiment, the assist torque control amount calculation unit 25b changes the assist torque characteristic map used for calculating the assist torque control amount during LK control and during normal operation, and further performs LK control. The assist torque characteristic used for the calculation has a characteristic that the assist torque value is larger than the assist torque characteristic used for the calculation at the normal time for the same steering torque T. As a result, during LK control, the driver receives higher assist torque with respect to the steering operation, so that the steering burden and discomfort felt by the driver during LK control compared to the normal time are suppressed.

  Further, the damping control unit 31 changes the damping correction amount map used for calculating the damping control amount during the LK control and during the normal time. Further, the damping control amount in the map during the LK control is changed in the map during the normal time. Compared to the damping control amount, the value for the same steering angular velocity θ ′ is small (the absolute value is large). During LK control, a high assist torque is received, so that the steering wheel 1 is likely to be cut and the driver may feel uncomfortable. During the LK control, the damping control unit 31 increases the damping control amount to increase the magnitude of the damping torque and suppress the ease of cutting. Thereby, the uncomfortable feeling of the driver is suppressed.

  Further, the torque differential control unit 32 changes the torque differential correction amount map used for the calculation of the torque differential control amount during the LK control and during the normal time, and the torque differential correction amount in the map during the LK control is The value for the same torque differential value T ′ is smaller than the torque differential correction amount in the time map. During LK control, a high assist torque is received, so that the steering wheel 1 is likely to be cut and the driver may feel uncomfortable. The torque differential control unit 32 reduces the torque differential correction amount during the LK control, thereby reducing the torque generated in response to the change in the steering torque T and suppressing the ease of cutting. Thereby, the uncomfortable feeling of the driver is suppressed.

Further, the hysteresis control unit 33 changes the hysteresis control amount map used for calculating the hysteresis control amount during the LK control and during the normal time, and the hysteresis control amount in the map during the LK control is Compared to the hysteresis control amount, the steering angle at a constant value is large, and the constant value is also large.
During LK control, a high assist torque is received, so that the steering wheel 1 is likely to be cut and the driver may feel uncomfortable. During the LK control, the hysteresis control unit 33 increases the torque that acts like a frictional force on the driver's steering by increasing the hysteresis control amount when the steering angle is greater than or equal to a predetermined steering angle. And suppresses the ease of cutting. Thereby, the uncomfortable feeling of the driver is suppressed.

  FIG. 14 is a flowchart showing the control of the assist torque control unit 25, the damping control unit 31, the torque differentiation control unit 32, the hysteresis control unit 33, and the adder 26 of the driving support device 30A. First, in step S201, the assist torque control unit 25, the damping control unit 31, the torque differentiation control unit 32, and the hysteresis control unit 33 receive inputs of the vehicle speed V, the steering torque T, the steering angle θ, and the steering angular velocity θ ′. At this time, each control unit accepts input of parameters used for its own control. Subsequently, in step S202, the LK determination unit 25a of the assist torque control unit 25, the LK determination unit 31a of the damping control unit 31, the LK determination unit 32a of the torque differential control unit 32, and the LK determination unit 33a of the hysteresis control unit 33 are as follows. The input of the LK in-control flag output from the LK control unit 23 is received. Subsequently, in step S203, the LK determination units 25a, 31a, 32a, and 33a determine whether LK control is being performed based on the LK control flag. If it is determined that the LK control is being performed (step S203, Yes), the control proceeds to step S204.

  In step S204, the assist torque control amount calculation unit 25b selects an assist torque characteristic map during LK control, and uses this to calculate an assist torque control amount. Subsequently, in step S205, the damping control unit 31 calculates the damping control amount using the damping correction amount map during the LK control. Subsequently, in step S206, the torque differential correction amount calculation unit 32b calculates the torque differential control amount using the torque differential correction amount map during the LK control. Subsequently, in step S207, the hysteresis control amount calculation unit 33b calculates a hysteresis control amount using a hysteresis control amount map during LK control. Subsequently, in step S208, the adder 26 determines the LK control amount output from the LK control unit 23, the assist torque control amount output from the assist torque control unit 25, and the damping control output from the damping control unit 31. And the torque differential control amount output from the torque differential control unit 32 and the hysteresis control amount output from the hiss control unit 33 are added and output to the electric motor control unit 9 as a target assist torque control amount. This control flow returns.

  On the other hand, if it is determined in step S203 that the LK control is not being performed (step S203, No), the control proceeds to step S209. In step S209, the assist torque control amount calculation unit 25b selects an assist torque characteristic map at the normal time, and uses this to calculate an assist torque control amount. Subsequently, in step S210, the damping control unit 31 calculates a damping control amount using a normal damping correction amount map. Subsequently, in step S211, the torque differential correction amount calculation unit 32b calculates a torque differential control amount using a normal torque differential correction amount map. Subsequently, in step S212, the hysteresis control amount calculation unit 33b calculates a hysteresis control amount using a normal hysteresis control amount map, and the control proceeds to step S208. In step S208, the adder 26 adds the LK control amount, the assist torque control amount, the damping control amount, the torque differential control amount, and the hysteresis control amount, and controls the electric motor as a target assist torque control amount. Output to section 9 and return.

  As described above, according to the driving support device 30A according to the second embodiment, it is possible to suppress the burden and discomfort felt during steering during LK control as compared to normal steering, and further during the LK control, the steering wheel 1 Occurrence of the ease of cutting can be suppressed, and the uncomfortable feeling can be further suppressed.

  Note that the assist torque control unit 25 included in the driving support device 30A according to the second embodiment can be appropriately replaced with the assist torque control units 25A, 25B, and 25C shown in FIGS.

(Another configuration example of the assist torque control unit)
Next, another configuration example of the assist torque control unit that can be replaced with the assist torque control unit 25 in the driving support devices 30 and 30A according to the first and second embodiments will be further described. FIG. 15 is a block diagram of Configuration Example 5 of the assist torque control unit. The assist torque control unit 25D includes assist torque control amount calculation units 25Da corresponding to the assist torque control amount calculation units 25Ba and 25Bb of the assist torque control unit 25B of the configuration example 3 illustrated in FIG. 8 and the switch unit 25Bc, respectively. 25Db, a switch unit 25Dc, an assist compensation control unit 25Dd when the LK control characteristics are varied, an assist compensation control unit 25De according to the presence or absence of driver steering, and multipliers 25Df and 25Dg.

  The assist torque control amount calculation unit 25Da stores an assist torque characteristic map 1 used during LK control. The assist torque control amount calculation unit 25Da stores a plurality of assist torque characteristic maps 1 corresponding to the vehicle speed V. Here, the assist torque characteristic map 1 has characteristics set so as to suppress a driver's burden and discomfort caused during steering during LK control. The assist torque control amount calculation unit 25Da calculates an assist torque control amount during LK control based on the vehicle speed V, the steering torque T, and the assist torque characteristic map 1, and outputs the calculated assist torque control amount to the multiplier 25Df.

  The assist compensation control unit 25Dd (hereinafter sometimes simply referred to as assist compensation control unit 25Dd) when the LK control characteristic is variable changes the LK control characteristic when the LK control characteristic by the LK control unit 23 is variable. The first assist compensation gain having a corresponding value is output to the multiplier 25Df. The first assist compensation gain will be described in detail later.

  The multiplier 25Df multiplies the assist torque control amount during the LK control by the first assist compensation gain, and outputs the result to the multiplier 25Dg.

  The assist compensation controller 25De (hereinafter sometimes simply referred to as assist compensation controller 25De) depending on whether or not the driver is steering is provided with a second assist compensation gain to the multiplier 25Dg depending on whether or not the driver is steering. Output. The second assist compensation gain will be described in detail later.

  The multiplier 25Dg multiplies the assist torque control amount during the LK control multiplied by the first assist compensation gain and the second assist compensation gain, and outputs this to the switch unit 25Dc as the assist torque control amount.

  The assist torque control amount calculation unit 25Db stores an assist torque characteristic map 2 that is normally used. The assist torque control amount calculation unit 25Db stores a plurality of assist torque characteristic maps 2 corresponding to the vehicle speed V. The assist torque control amount calculation unit 25Db calculates a normal assist torque control amount based on the vehicle speed V, the steering torque T, and the assist torque characteristic map 2, and outputs it to the switch unit 25Dc.

  The switch unit 25Dc receives an input of an LK control flag output from the LK control unit 23 and an input of an assist torque control amount output from each of the assist torque control amount calculation units 25Da and 25Db. When “1”, the assist torque control amount input from the assist torque control amount calculation unit 25Da is output to the adder 26 (see FIGS. 1 and 10), and when the LK control flag is “0”, the assist is performed. The assist torque control amount input from the torque control amount calculation unit 25Db is output to the adder 26.

  During LK control, the adder 26 includes an LK control amount, an assist torque control amount during LK control output from the assist torque control unit 25D, a damping control amount output from the damping control unit 31, and a torque differential control unit. The torque differential control amount during LK control output from 32 and the hysteresis control amount during LK control output from the hysteresis control unit 33 are added and output to the electric motor control unit 9 as a target assist torque control amount. To do. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. As a result, both LK control and driver assistance are performed.

  Further, in the normal time, the adder 26 adds the normal assist torque control amount, the damping control amount, the normal torque differential control amount, and the normal hiss control amount, and this is added to the target assist torque control. The amount is output to the electric motor controller 9. The electric motor control unit 9 drives the electric motor 5 according to the target assist torque control amount. This assists the driver with steering.

  Next, the assist compensation control units 25Dd and 25De, the first assist compensation gain, and the second assist compensation gain will be described in detail.

First, the assist compensation control unit 25Dd and the first assist compensation gain will be described.
First, the LK control unit 23 is configured such that its LK control characteristics change according to a change in reliability of the running state of the vehicle Ve and the recognition state of the surrounding situation in the LK control. The reliability of the recognition state of the traveling state of the vehicle Ve and the surrounding situation is such that the accuracy when the traveling lane is recognized by the camera 21 and the image processing unit 22 varies depending on, for example, daytime, nighttime, and weather (when the weather is fine and when it rains). Yes. Therefore, the reliability can also be changed according to the change in accuracy.

  Therefore, the assist compensation control unit 25Dd multiplies the assist torque control amount during the LK control calculated and output by the assist torque control amount calculation unit 25Da by the assist compensation gain according to the change in the LK control characteristic by the LK control unit 23. Thus, the assist torque control amount is compensated according to the change in the LK control characteristics. As a result, even when the LK control characteristics change, the driver can receive an appropriate steering assist according to the change, and the burden and uncomfortable feeling are suppressed.

  FIG. 16 is a diagram illustrating an example of the relationship between the LK control amount characteristic and the assist torque control amount characteristic. The LK control amount characteristic shown in the left diagram of FIG. 16 shows the relationship between (target angle−steering angle θ) and the LK control amount. The LK control amount increases at a constant gradient as (target angle−steering angle θ) increases from zero, and is set to have a constant MAX value above a predetermined (target angle−steering angle θ). The MAX value is variable according to the reliability of the recognition state in the LK control. The higher the reliability, the higher the MAX value is set to MAX value 1, MAX value 2, and MAX value 3.

  The assist compensation control unit 25Dd stores a correction gain map according to the MAX value of the LK control amount. Here, the correction gain is set to a larger value as the MAX value of the LK control amount is larger. As a result, as shown in the diagram on the right side of FIG. 16, for the same steering torque T, the assist torque control amount increases as the reliability increases, that is, the MAX value increases.

  FIG. 17 is a diagram illustrating another example of the relationship between the LK control amount characteristic and the assist torque control amount characteristic. As shown in the diagram on the left side of FIG. 17, the LK control amount increases with a constant gradient as (target angle−steering angle θ) increases from zero, and is constant above a predetermined (target angle−steering angle θ). The maximum value is set. The increase gradient of the LK control amount (LK control gradient) is variable according to the reliability of the recognition state in the LK control, and is set so that the LK control gradient increases as the reliability increases. The magnitude of the LK control gradient corresponds to the magnitude of the feedback gain that determines the responsiveness of the feedback control in the LK control. The larger the feedback gain, the larger the LK control gradient.

  The assist compensation control unit 25Dd stores a correction gain map corresponding to the LK control gradient. Here, the correction gain is set to a larger value as the LK control gradient is larger. As a result, as shown in the diagram on the right side of FIG. 17, the assist torque control amount increases as the LK control gradient increases with respect to the same steering torque T.

  The LK control unit 23 is configured to change both the LK control amount MAX value and the LK control gradient, and the assist compensation control unit 25Dd corresponds to each of the LK control amount MAX value and the LK control gradient. A correction gain map is stored.

  FIG. 18 is a block diagram of the assist compensation controller 25Dd. The assist compensation controller 25Dd includes correction gain calculators 25Dda and 25Ddb, and a multiplier 25Ddc.

  The correction gain calculation unit 25Dda stores a correction gain map corresponding to the LK control amount MAX value, and corrects using the current LK control amount MAX value input from the LK control unit 23 and the correction gain map. The gain is calculated and output to the multiplier 25Ddc. The correction gain map is set so that the correction gain increases as the LK control amount MAX value increases. Note that the value with the “LK” control amount MAX value “medium” is, for example, an initial setting value of the LK control amount MAX value, and the correction gain is 1 at this time.

  The correction gain calculator 25Ddb stores a correction gain map corresponding to the LK control gradient, and calculates the correction gain using the current LK control gradient and the correction gain map input from the LK control unit 23. , Output to the multiplier 25Ddc. The correction gain map is set so that the correction gain increases as the LK control gradient increases. Note that the value of the LK control amount gradient “medium” is, for example, an initial setting value of the LK control gradient, and the correction gain is 1 at this time.

  The multiplier 25Ddc multiplies the correction gains output from the correction gain calculators 25Dda and 25Ddb, and outputs the result to the multiplier 25Df as a first assist compensation gain.

  Next, the assist compensation control unit 25De and the second assist compensation gain will be described. When the assist torque control amount is increased because the LK control is being performed while the LK control is being performed and the driver is not steering, the steering torque T is detected because the steering assist is performed accordingly. As a result, steering assist is performed regardless of the driver's steering, and the followability to the travel line in LK control may be reduced. On the other hand, as shown in FIG. 19, when the driver is steered, the follow-up performance is reduced by increasing the assist torque control amount at the same steering torque T as compared with the case where there is no steering. It is suppressed. The assist compensation control unit 25De has a function of calculating a second assist compensation gain that increases the assist torque control amount when the driver is steering.

  FIG. 20 is a block diagram of the assist compensation control unit 25De. The assist compensation controller 25De includes correction gain calculators 25Dea, 25Deb, and 25Dec, multipliers 25Ded, 25Def, and 25Deg, and a differentiator 25Deh.

  The correction gain calculator 25Dea stores a correction gain map corresponding to the steering torque T, calculates the correction gain using the steering torque T and the correction gain map, and outputs the correction gain to the multiplier 25Deg. The map of the correction gain according to the steering torque T is used for steady steering judgment of the driver, and in the case where the absolute value of the steering torque T is in the range between the line L1 and the line L3 where A0 or less. It is determined that there is no steering, the correction gain is 1, and when the absolute value of the steering torque is greater than A0, it is determined that there is steering and the correction gain is set to a value greater than 1. The correction gain is set to be constant at a predetermined MAX value when the absolute value of the steering torque is larger than A1 indicated by lines L2 and L4.

The multiplier 25Ded outputs θ ′ × T obtained by multiplying the steering torque T and the steering angular velocity θ ′ to the correction gain calculation unit 25Deb.
The correction gain calculation unit 25Deb stores a correction gain map corresponding to θ ′ × T, calculates the correction gain using θ ′ × T and the correction gain map, and outputs the correction gain to the multiplier 25Deg. The correction gain map corresponding to θ ′ × T is used for the driver's transient steering determination. When θ ′ × T is large, this corresponds to a situation where the driver has a strong intention to steer and is actively steering. Therefore, when θ ′ × T is greater than the positive value A2 smaller than A0 described above, steering is performed. As a result, the correction gain is set to be larger than 1. On the other hand, when θ ′ × T is small, this corresponds to a situation where the driver's steering intention is weak and the steering is passively performed. However, the driver also indicates that the steering wheel is automatically steered during LK control. In view of the high possibility of understanding, when the absolute value of θ ′ × T is larger than the negative value B2 whose absolute value is larger than A0 described above, it is determined that there is steering, and the correction gain is a value larger than 1. It is set to be.

The differentiator 25Deh differentiates the steering torque T and outputs it to the multiplier 25Def as a torque differential value T ′. The multiplier 25Def outputs θ × T ′ obtained by multiplying the torque differential value T ′ and the steering angle θ to the correction gain calculator 25Dec. Here, instead of the steering angle θ, (steering angle θ−target angle) may be used.
The correction gain calculator 25Dec stores a correction gain map corresponding to θ × T ′, calculates the correction gain using θ × T ′ and the correction gain map, and outputs the correction gain to the multiplier 25Deg. The correction gain map according to θ × T ′ is used for the driver's transient steering determination. When θ × T ′ is large, this corresponds to a situation where the driver has a strong intention to steer and is actively steering. Therefore, when θ × T ′ is greater than the above-described positive value A3 which is smaller than A0, steering is performed. As a result, the correction gain is set to be larger than 1. On the other hand, when θ × T ′ is small, this corresponds to a situation where the driver's intention to steer is weak and the vehicle is passively steered. However, the driver also knows that the steering wheel is automatically steered during LK control. In view of the high possibility of understanding, when the absolute value of θ × T ′ is larger than the negative value B3 whose absolute value is larger than A0 described above, it is determined that there is steering and the correction gain is a value larger than 1. It is set to be.

  The multiplier 25Ddeg multiplies the correction gains output from the correction gain calculators 25Dea, 25Deb, and 25ec, and outputs the result to the multiplier 25Dg as a second assist compensation gain.

  When the assist torque control unit 25D is used, the driving support device compensates for the assist torque control amount according to the change in the LK control characteristics. Therefore, even when the LK control characteristics change, the driver responds to the change. Appropriate steering assistance can be received, and burden and discomfort can be suppressed. Furthermore, since the driving assistance device increases the assist torque control amount when the driver is steering, compared with the case where there is no steering, a decrease in the followability to the travel line in the LK control is suppressed.

  The correction gain maps shown in FIGS. 18 and 20 are examples, and the present invention is not limited to this. For example, the correction gain map may have characteristics such that the parameter range on the horizontal axis where the correction gain is 1 is wider than in the case of FIGS. Also, in the correction gain map of the correction gain calculators 25Deb and 25Dec in FIG. 20, the absolute values of A2 and B2 may be equal, or the absolute values of A3 and B3 may be equal.

  FIG. 21 is a flowchart illustrating control when the assist torque control unit 25 is replaced with an assist torque control unit 25D in the driving support device 30A. First, in step S301, the assist torque control unit 25D, the damping control unit 31, the torque differentiation control unit 32, and the hysteresis control unit 33 receive inputs of the vehicle speed V, the steering torque T, the steering angle θ, and the steering angular velocity θ ′. At this time, each control unit accepts input of parameters used for its own control. Subsequently, in step S302, the switch unit 25Dc of the assist torque control unit 25D, the LK determination unit 31a of the damping control unit 31, the LK determination unit 32a of the torque differential control unit 32, and the LK determination unit 33a of the hysteresis control unit 33 are: The assist torque control unit 25D receives input of LK control characteristics (LK control amount MAX value and LK control gradient), and receives an input of the LK controlling flag output from the LK control unit 23. Subsequently, in step S303, the switch unit 25Dc and the LK determination units 31a, 32a, and 33a determine whether LK control is being performed based on the LK control flag. When it is determined that the LK control is being performed (step S303, Yes), the control proceeds to step S304.

  In step S304, the assist torque control amount calculation unit 25Da of the assist torque control unit 25D calculates the assist torque control amount using the assist torque characteristic map 1 during LK control. Subsequently, in step S305, the assist compensation control unit 25Dd calculates a first assist compensation gain when the LK control characteristics are variable, and the multiplier 25Df multiplies the assist torque control amount by the first assist compensation gain. Subsequently, in step S306, the assist compensation control unit 25De calculates a second assist compensation gain according to the presence or absence of driver steering, and the multiplier 25Dg multiplies the assist torque control amount by the first assist compensation gain. Further, the second assist compensation gain is multiplied, and this is output as an assist torque control amount by the switch unit 25Dc.

  Subsequently, in step S307, the damping control unit 31 calculates a damping control amount using a damping correction amount map during LK control. Subsequently, in step S308, the torque differential correction amount calculation unit 32b calculates a torque differential control amount using the torque differential correction amount map during LK control. Subsequently, in step S309, the hysteresis control amount calculation unit 33b calculates the hysteresis control amount using the hysteresis control amount map during the LK control. Subsequently, in step S310, the adder 26 controls the LK control amount output from the LK control unit 23, the assist torque control amount output from the assist torque control unit 25D, and the damping control output from the damping control unit 31. And the torque differential control amount output from the torque differential control unit 32 and the hysteresis control amount output from the hiss control unit 33 are added and output to the electric motor control unit 9 as a target assist torque control amount. This control flow returns.

  On the other hand, if it is determined in step S303 that the LK control is not being performed (step S303, No), the control proceeds to step S311. In step S311, the assist torque control amount calculation unit 25Db of the assist torque control unit 25D calculates the assist torque control amount using the normal assist torque characteristic map 2, and the switch unit 25Dc outputs this as the assist torque control amount. To do. Subsequently, in step S312, the damping control unit 31 calculates a damping control amount using a normal damping correction amount map. Subsequently, in step S313, the torque differential correction amount calculation unit 32b calculates a torque differential control amount using a normal torque differential correction amount map. Subsequently, in step S314, the hysteresis control amount calculation unit 33b calculates the hysteresis control amount using the normal hysteresis control amount map, and the control proceeds to step S310. In step S310, the adder 26 adds the LK control amount, the assist torque control amount, the damping control amount, the torque differential control amount, and the hysteresis control amount, and uses this as the target assist torque control amount to control the electric motor. Output to section 9 and return.

  The present invention is not limited to the above embodiment. What was comprised combining each component mentioned above suitably is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

DESCRIPTION OF SYMBOLS 1 Steering wheel 5 Electric motor 9 Electric motor control part 10 Steering torque sensor 12 Electric power steering system 23 LK control part 25, 25A, 25B, 25C, 25D Assist torque control part 25Dd, 25De Assist compensation control part 30, 30A Driving assistance device

Claims (5)

An electric motor and an electric motor control unit that drives and controls the electric motor according to a given control amount, and is mounted on a vehicle including a steering mechanism that drives the electric motor and controls a steering angle of a steering wheel of the vehicle. A driving support device,
Steering torque detection means for detecting steering torque input to the steering wheel of the vehicle;
An assist torque control means for calculating and outputting an assist torque control amount based on the steering torque and an assist torque characteristic indicating a relationship between the steering torque and an assist torque for assisting a driver's steering;
An assist compensation control amount calculating means for calculating an assist compensation control amount for compensating the assist torque control amount;
Lane maintenance support control means that can switch between an operation state and a non-operation state, and calculates and outputs a lane maintenance support control amount for causing the vehicle to travel along a target line in a travel lane on which the vehicle travels. When,
A target control amount calculation means for calculating a target control amount based on the assist torque control amount, the lane keeping support control amount and the assist compensation control amount in the operating state, and outputting the target control amount to the motor control unit;
With
In the operating state, the target control amount calculation means adds the assist compensation control amount that is torque to the assist torque control amount, or sets the gain K that is a positive constant as the assist compensation control amount (1 + K). Multiplying the assist torque control amount,
The assist compensation control amount increases with an increase in the steering torque, takes a maximum value when the steering torque is not less than a predetermined value, and the maximum value increases as the vehicle speed of the vehicle increases.
The assist torque control means is characterized in that the lane keeping assist control means outputs different assist torque control amounts for the same steering torque in the operating state and the non-operating state.   The driving assist device according to claim 1, wherein the assist torque control unit outputs a larger assist torque control amount in the operating state than in the non-operating state with respect to the same steering torque. .   The driving assist device according to claim 1, wherein the assist torque control unit switches the assist torque characteristic used for calculation between the operation state and the non-operation state.   The driving assistance device according to any one of claims 1 to 3, wherein the assist compensation control amount calculation unit sets the assist compensation control amount to zero when the steering torque is equal to or less than a predetermined value.   The driving according to any one of claims 1 to 4, wherein the assist torque control unit is configured to calculate an assist torque control amount corresponding to a characteristic of the lane keeping assist control amount. Support device.

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