JP2015151086A - vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device capable of suppressing driver's discomfort during lane keeping assist control.SOLUTION: A vehicle control device 10 can execute a lane keeping assist control for keeping a vehicle travel road to a target travel road. Under the lane keeping assist control, travel positions at which steering power P (active-passive state amount P) calculated by adding up a product between a steering angle speed θ' and a steering torque T (first steering power P1) and a product between a steering angle θ and a differential value T' of the steering torque T (second steering power P2) is equal to or smaller than a predetermined value A, are set to a target course (target track).

Description

  The present invention relates to a vehicle control device.

  Conventionally, in lane keep assist control, a vehicle control device that changes a target course within a lane range based on steering torque is known (for example, Patent Document 1).

JP 2007-326447 A

  In the conventional vehicle control device, the driver's steering intention is determined by the steering torque, and the driver's steering intention cannot be determined until the steering torque actually changes. Therefore, it is difficult to accurately determine the driver's driving intention. It is. For this reason, a divergence between the set target course and the target course intended by the driver tends to occur, and the driver tends to feel uncomfortable.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a vehicle control device that can suppress a driver's uncomfortable feeling in lane keep assist control.

  In order to solve the above-described problem, the vehicle control device according to the present invention can execute lane keep assist control for assisting steering so that the vehicle travels along a set target course. In the lane keep assist control, The traveling position at which the steering power calculated by adding the product of the steering angular velocity and the steering torque and the product of the steering angle and the differential value of the steering torque is equal to or less than a predetermined value is set as the target course. And

  The vehicle control device according to the present invention has an effect that a driver's uncomfortable feeling can be suppressed in the lane keep assist control.

FIG. 1 is a block diagram showing a schematic configuration of a vehicle control apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the active passive state quantity and the lane keep target trajectory shift quantity. FIG. 3 is a flowchart showing a lane keep assist control process in the vehicle control apparatus of the present embodiment.

  Hereinafter, embodiments of a vehicle control device according to the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[Embodiment]
First, the configuration of the vehicle control device 10 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a schematic configuration of a vehicle control apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing a relationship between an active passive state quantity and a lane keep target trajectory shift quantity.

  The vehicle control device 10 can execute lane keep assist control for providing steering assistance so that a vehicle on which the vehicle control device 10 is mounted travels along a set target course (also referred to as a target travel path or a target trajectory). It is. The lane keep assist control can also be said to be control for maintaining the travel path of the vehicle on which the vehicle control device 10 is mounted as the target travel path. As shown in FIG. 1, the vehicle control apparatus 10 includes an index calculation unit 11, a target locus calculation unit 12, a lane keep control amount calculation unit 13, and a differentiator 14 as functions related to the lane keep assist control. .

  The index calculator 11 calculates an active passive state quantity (steering power) P. The active passive state quantity P is an index representing the state of the steering operation of the driver of the vehicle. A smaller active passive state amount P indicates a “passive state” in which a steering operation with a relatively weak steering intention of the driver is being performed, and a larger active passive state amount P indicates a relatively smaller steering position of the driver. An “active state” in which a strong steering operation is performed is shown.

In the present embodiment, as the active passive state amount P, a steering work rate that is an index representing a work rate (physical amount representing energy used per unit time) in the steering operation of the driver with respect to the steering wheel of the vehicle is used (hereinafter referred to as “active passive state amount P”). Then, the active passive state quantity P is also expressed as a steering power P). The steering power P is, for example, the first steering power P1 based on the product of the steering angular velocity (the time derivative of the steering angle of the vehicle steering wheel) and the steering torque input to the vehicle steering wheel by the driver, the steering angle and the steering. It can be calculated by the following equation (1) by adding the second steering power P2 based on the product of the time derivative (differential value) of the torque.
P = P1 + P2
= A {θ (t) ′ * T (t)} + b {θ (t) * T (t) ′} (1)

  Here, θ (t) is a steering angle, and θ (t) ′ represents a steering angular velocity. T (t) is a steering torque, and T (t) ′ is a time derivative (differential value) of the steering torque. t represents time. a and b are parameters that can be set as appropriate. In the following description, these may be simplified, and θ (t) may be represented as θ, θ (t) ′ as θ ′, T (t) as T, and T (t) ′ as T ′. In the present embodiment, regarding the direction of the steering angle θ and the steering angular velocity θ ′, the left rotation direction is a positive direction and the right rotation direction is a negative direction.

  The steering angle θ and the steering speed θ ′ used in the above equation (1) are acquired based on, for example, a detection signal of a steering angle sensor mounted on the vehicle and input to the index calculation unit 11. Further, the steering torque T is acquired based on, for example, a detection signal of a torque sensor mounted on the vehicle, and is input to the index calculation unit 11. In this embodiment, the steering torque differential value T ′ is calculated by inputting the steering torque T to the differentiator 14 and input to the index calculation unit 11. The index calculation unit 11 calculates the active passive state quantity P by the above equation (1) using these input information, and outputs it to the target locus calculation unit 12.

  The target trajectory calculation unit 12 corrects the target trajectory of the lane keep assist control according to the active passive state quantity P calculated by the index calculation unit 11. Specifically, the target trajectory calculation unit 12 first calculates the target trajectory shift amount (target trajectory shift amount) δ of the lane keep assist control according to the active passive state amount P. The target locus shift amount δ is a change amount for shifting a preset target locus to the left or right in the traveling direction. In general, the target trajectory used in the lane keep assist control is often set at the center of the travel lane. In this case, the vehicle control device 10 travels along the target trajectory according to, for example, the target trajectory shift amount δ. It can be changed to the left or right side in the lane.

  The target trajectory calculation unit 12, for example, based on the correspondence relationship between the active passive state quantity P shown in FIG. 2 and the target trajectory shift quantity δ (denoted as “lane keep target trajectory shift quantity” in FIG. 2), A target locus shift amount δ is set according to the value of P. The horizontal axis of FIG. 2 indicates the active passive state quantity P, the vertical axis indicates the target locus shift amount δ, and a graph showing the correspondence between these is shown by a solid line.

  As shown in FIG. 2, the target locus calculation unit 12 determines that the driver's steering operation is in the active state when the active passive state amount P is greater than a predetermined value A (for example, A = 0). Then, as shown in FIG. 2, when the active passive state quantity P is in the active state region larger than the predetermined value A, the target locus calculating unit 12 increases the target locus shift amount δ as the active passive state quantity P increases. Is set to increase in the positive direction. In this case, the target locus shifts to the left. As described above, in the present embodiment, the steering angle θ and the steering angular velocity θ ′ are also set such that the positive direction is the left direction of the steering direction and the negative direction is the right direction of the steering direction. That is, when the driver's steering direction matches the direction in which the target locus is shifted by the target locus shift amount δ, and the driver's steering operation is active, the target locus is shifted in the direction of the driver's steering intention. become.

  On the other hand, as shown in FIG. 2, the target trajectory calculation unit 12 is set so that the target trajectory shift amount δ is 0 when the active passive state amount P is in the passive state region of the predetermined value A or less. . That is, in a passive state where the driver does not intend to steer, the target locus is not shifted with the actual locus at that time as the target locus.

  Then, the target trajectory calculation unit 12 corrects a predetermined target trajectory of the lane keep control (denoted as “lane keep target trajectory” in FIG. 1) based on the target trajectory shift amount δ derived as described above, and keeps the lane keep. Output to the control amount calculation unit 13. The “lane keep target locus” is calculated by the vehicle control device 10 based on various information such as the driving state of the vehicle and the operation state of the driver, and is input to the target locus calculating unit 12. In the following description, the target trajectory output from the target trajectory calculation unit 12 to the lane keep control amount calculation unit 13 is also referred to as “corrected target trajectory”. The corrected target trajectory is calculated, for example, so that the lane keep target trajectory is shifted by the target trajectory shift amount δ in the steering direction. In other words, while the driver is actively performing the steering operation, the corrected target locus is changed to the steering direction due to the influence of the target locus shift amount δ in the steering direction. Then, when the driver's steering operation transitions to the passive state, the newly accumulated target locus shift amount δ disappears, so that the corrected target locus converges to the changed position in the active state.

  The lane keep control amount calculator 13 adjusts the control amount (lane keep control amount) of the lane keep assist control according to the corrected target locus calculated by the target locus calculator 12. The lane keep control amount is required for an in-vehicle device (for example, an electric power steering device (EPS), a front steer device, a rear steer device, etc.) used for the lane keep assist control to make the vehicle travel locus follow the target locus. The control amount (for example, drive current value, drive duty ratio, etc.) of these in-vehicle devices is included.

The lane keep control amount calculation unit 13 can calculate the lane keep control amount by, for example, the following equation (2).
Lane-keep control amount = Actual deviation x Lane-keep gain (2)

  Here, the “real deviation” in the equation (2) is a deviation of the actual trajectory of the vehicle with respect to the corrected target trajectory input from the target trajectory calculation unit 12. The actual trajectory of the vehicle is measured by various sensors mounted on the vehicle, for example, and is input to the lane keep control amount calculation unit 13. “Actual deviation” is an example of information indicating the current lane keeping state, and may be replaced with other information. Also, the “lane keep gain” in the above equation (2) is a parameter that determines the amount of the lane keep control amount in accordance with the actual deviation. In the present embodiment, the lane keep gain can be a predetermined value.

  The differentiator 14 outputs a differential value of the input information. In the present embodiment, when the steering torque T is input, the differentiator 14 outputs a differential value T ′ of the steering torque to the index calculation unit 11.

  Each function of the vehicle control device 10 described above can be realized by one or a plurality of ECUs (Electronic Control Units) that are mounted on the vehicle and control driving of each part of the vehicle. 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 interface. Each function of the vehicle control device 10 described above is such that, in the ECU, an application program held in the ROM is loaded into the RAM and executed by the CPU, whereby various devices in the vehicle are operated under the control of the CPU. This is realized by reading and writing data in RAM and ROM.

  Next, the operation of the vehicle control apparatus 10 according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing a lane keep assist control process in the vehicle control apparatus of the present embodiment. A series of processing shown in the flowchart of FIG. 3 is performed by the vehicle control device 10 at predetermined intervals, for example.

  In step S1, the steering torque T, the steering angular velocity θ ′, and the steering angle θ are measured by various sensors in the vehicle. When the process of step S1 is completed, the process proceeds to step S2.

  In step S2, the differentiator 14 calculates a differential value T ′ = dT / dt of the steering torque based on the steering torque T measured in step S1. When the process of step S2 is completed, the process proceeds to step S3.

  In step S3, the index calculation unit 11 calculates an index representing the state of the steering operation of the driver of the vehicle. Specifically, the index calculation unit 11 is based on the steering torque T, the steering angular velocity θ ′, and the steering angle θ measured in step S1, and the steering torque differential value T ′ calculated in step S2. Thus, the active passive state quantity (steering power) P in the current control cycle is calculated using the above equation (1). When the process of step S3 is completed, the process proceeds to step S4.

  In step S4, the target locus calculation unit 12 calculates the target locus shift amount δ based on the active passive state amount P calculated in step S3. The target trajectory calculation unit 12 shifts the target trajectory so as to correspond to the active passive state amount P in the current control cycle based on the correspondence relationship between the active passive state amount P and the target trajectory shift amount δ shown in FIG. Set the quantity δ. When the process of step S4 is completed, the process proceeds to step S5.

  In step S5, the target trajectory calculation unit 12 uses the target trajectory shift amount δ set in step S4 to calculate and input the predetermined target trajectory (lane keep-up) of the lane keep assist control calculated and input in the vehicle control device 10. Target trajectory) is corrected, and a corrected target trajectory is calculated. The target locus calculation unit 12 specifies the steering direction in the current control cycle based on, for example, information on the steering angle θ measured in step S1. Then, the target trajectory calculation unit 12 corrects the lane keep target trajectory so as to be shifted by the target trajectory shift amount δ in this steering direction. Note that the corrected target locus calculated in this step is held as the lane keep target locus in the next control cycle. That is, the correction amount of the lane keep target locus based on the target locus shift amount δ is integrated. When the process of step S5 is completed, the process proceeds to step S6.

  In step S6, the lane keep control amount calculation unit 13 calculates the lane keep control amount. The lane keep control amount calculation unit 13 is based on the deviation (actual deviation) between the corrected target trajectory calculated in step S5 and the actual trajectory of the current control cycle as shown in the above equation (2). Then, the lane keep control amount calculated by multiplying the actual deviation by the lane keep gain is output. The vehicle control device 10 executes lane keep assist control using the lane keep control amount output in this way. When the process of step S5 is completed, the process of this control flow in the current control cycle is terminated.

  As described above, the vehicle control device 10 according to the present embodiment can execute lane keep assist control for providing steering assistance so that the vehicle travels along the set target course (target locus). In this lane keeping assist control, the product of the steering angular velocity θ ′ and the steering torque T (first steering power P1) and the product of the steering angle θ and the differential value T ′ of the steering torque (second steering power P2) are obtained. As shown in FIG. 2, when the steering power P (active passive state amount P) calculated by addition exceeds a predetermined value A (that is, P> A), the driver's steering operation is active with a steering intention. It is determined that it is in a state. In this case, the vehicle control device 10 corrects the target locus of the lane keep assist control to be shifted in the steering direction based on the target locus shift amount δ derived according to the steering power P. As a result, when the steering operation is in the active state, the actual trajectory is shifted so as to follow the target trajectory corrected according to the driver's steering intention. Therefore, even if there is a situation where the driver's intention is contrary to the lane keep assist control, for example, the driver wants to drive at the end of the lane, the target course can be changed appropriately according to the driver's intention, and the uncomfortable feeling of the steering feel is suppressed. it can.

  On the other hand, as shown in FIG. 2, when the operation power P is equal to or less than a predetermined value A (that is, P ≦ A), the vehicle control device 10 determines that the driver's steering operation is a passive state without steering intention. In this case, since the target locus shift amount δ is set to be 0, the vehicle control device 10 maintains the target locus in accordance with the actual locus without correcting the target locus.

  By the way, after the driver steers in an active state and changes the actual trajectory of the vehicle to a desired travel position (for example, a position on the left or right side of the travel lane), the driver must maintain the travel at this travel position. Therefore, it is considered that the steering operation shifts to the passive state without intentional steering. That is, the vehicle control device 10 of the present embodiment converges the driver's steering operation to the passive state in the lane keep assist control. In other words, the vehicle control device 10 sets the travel position at which the steering power P is equal to or less than the predetermined value A in the lane keep assist control as the target course (target trajectory).

  With this configuration, in addition to the first steering power P1 related to the steering torque T, the determination of the driver's steering intention (passive state) is made based on the determination based on the second steering power P2 related to the steering torque differential value T ′. By making the determination, it is possible to reduce the difference between the travel position intended by the driver and the target course, so that it is possible to suppress a sense of discomfort felt by the driver in the lane keep assist control.

  As mentioned above, although embodiment of this invention was described, the said embodiment was shown as an example and is not intending limiting the range of invention. The above-described embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. The above-described embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof, as long as they are included in the scope and gist of the invention.

10 Vehicle control device P Active passive state quantity (steering power)

Claims (1)

Lane keep assist control can be executed to assist steering so that the vehicle travels along the set target course,
In the lane keep assist control, the travel position where the steering power calculated by adding the product of the steering angular velocity and the steering torque and the product of the steering angle and the differential value of the steering torque becomes a predetermined value or less is determined as the target course. The vehicle control apparatus characterized by setting to.

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