Lane keep control apparatus and method for automotive vehicle

Claim 2

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section.

Claim 3

A lane keep control apparatus for an automotive vehicle as claimed in claim 1 , wherein the lane keep control apparatus further comprises: an in-vehicle information producing section that produces the information to a vehicular occupant in a vocal form or in a display form; and a warning section that produces the information from the in-vehicle information producing section to a vehicular occupant when the divergence determining section determines that the tendency of the divergence of the vehicle from the traffic lane occurs, the warning section modifying the content of the information to the vehicular occupant in accordance with a frequency of execution of the control to avoid the divergence of the vehicle from the traffic lane.

Claim 4

A lane keep control apparatus for an automotive vehicle as claimed in claim 1 , wherein the lane keep control apparatus further comprises: an external vehicle information producing section that produces the information to an external to the vehicle; and a warning section that produces the information from the external vehicle information producing section to the external to the vehicle when the divergence determining section determines that the tendency of the divergence of the vehicle from the traffic lane occurs, the warning section modifying the content of the information production to the external to the vehicle in accordance with a frequency of execution of the control to avoid the divergence of the vehicle from the traffic lane.

Claim 5

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section, wherein the driving force controlled variable correcting section corrects the driving force controlled variable in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with an elapse of time from a time at which the control executed to avoid the divergence of the vehicle from the traffic lane is started.

Claim 6

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section, wherein the driving force controlled variable correcting section corrects the driving force controlled variable in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with an elapse of time from a time at which the control executed to avoid the divergence of the vehicle from the traffic lane is started.

Claim 7

A lane keep control apparatus for an automotive vehicle as claimed in claim 4 , wherein the driving force controlling section is enabled to control braking forces of at least left and right road wheels of the vehicle individually and separately from each other.

Claim 8

A lane keep control apparatus for an automotive vehicle as claimed in claim 4 , wherein the driving force controlled variable calculating section calculates a target yaw moment from a difference between a future estimated lateral displacement of the vehicle with respect to the traffic lane estimated from the travel state of the vehicle detected by the travel state detecting section and a lateral displacement limit value and calculates the driving force controlled variable of each road wheel on the basis of the calculated target yaw moment.

Claim 9

A lane keep control apparatus for an automotive vehicle as claimed in claim 6 , wherein the driving force controlled variable correcting section reduces the lateral displacement limit value when the target yaw moment is calculated in accordance with the elapse of time from a time at which the control executed to avoid the divergence of the vehicle from the traffic lane is started.

Claim 10

A lane keep control apparatus for an automotive vehicle as claimed in claim 6 , wherein the driving force controlled variable correcting section augments a control gain to be multiplied with the difference between the future estimated lateral displacement of the vehicle when the target yaw moment is calculated and the lateral displacement limit value.

Claim 11

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section, wherein the driving force controlled variable correcting section corrects the driving force controlled variable of each road wheel of the vehicle in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a frequency of the control executed to avoid the divergence of the vehicle from the traffic lane.

Claim 12

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section, wherein the driving force controlled variable correcting section corrects the driving force controlled variable of each road wheel of the vehicle in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a frequency of the control executed to avoid the divergence of the vehicle from the traffic lane.

Claim 13

A lane keep control apparatus for an automotive vehicle as claimed in claim 9 , wherein the driving force controlling section is enabled to control at least the driving forces of left and right road wheels individually and separately from each other.

Claim 14

A lane keep control apparatus for an automotive vehicle as claimed in claim 9 , wherein the driving force controlled variable calculating section calculates a target yaw moment from a difference between a future lateral displacement of the vehicle with respect to the traffic lane estimated from the travel state of the vehicle detected by the travel state detecting section and a lateral displacement limit value and calculates the driving force controlled variable of each road wheel on the basis of the target yaw moment.

Claim 15

A lane keep control apparatus for an automotive vehicle as claimed in claim 11 , wherein the driving force controlled variable correcting section reduces the lateral displacement limit value when the target yaw moment is calculated in accordance with a frequency of execution of the control to avoid the divergence of the vehicle from the traffic lane.

Claim 16

A lane keep control apparatus for an automotive vehicle as claimed in claim 11 , wherein the driving force controlled variable correcting section increases a control gain to be multiplied with a difference between the future lateral displacement of the vehicle when the target yaw moment is calculated and the lateral displacement limit value in accordance with a frequency of execution of the control to avoid the divergence of the vehicle from the traffic lane.

Claim 17

A lane keep control apparatus for an automotive vehicle as claimed in claim 9 , wherein the divergence determining section modifies a timing of the determination of the tendency of the divergence of the vehicle from the traffic lane in accordance with a frequency of execution of the control to avoid the divergence of the vehicle from the traffic lane.

Claim 18

A keep control apparatus for an automotive vehicle as claimed in claim 14 , wherein the divergence determining section determines that the tendency of the divergence of the vehicle from the traffic lane occurs when the future lateral displacement with respect to the traffic lane estimated from the travel state of the vehicle detected by the travel state detecting section is equal to or larger than the lateral displacement limit value.

Claim 19

A lane keep control apparatus for an automotive vehicle as claimed in claim 15 , wherein the divergence determining section reduces the lateral displacement limit value in accordance with the frequency of execution of the control to avoid the divergence of the vehicle from the traffic lane to make earlier a timing at which the divergence determining section determines whether the tendency of the divergence of the vehicle from the traffic lane occurs.

Claim 20

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section, wherein the driving force controlled variable correcting section corrects the driving force controlled variable in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with an elapse of time from a time at which the control executed to avoid the divergence of the vehicle from the traffic lane is started, wherein the driving force controlled variable calculating section calculates a target yaw moment from a difference between a future estimated lateral displacement of the vehicle with respect to the traffic lane estimated from the travel state of the vehicle detected by the travel state detecting section and a lateral displacement limit value and calculates the driving force controlled variable of each road wheel on the basis of the calculated target yaw moment, wherein the driving force controlled variable calculating section comprises: a future estimated lateral displacement value calculating section that calculates the future estimated lateral displacement value (XS) as follows: XS=Tt×V×(φ+Tt×V×β)+X, wherein Tt denotes a headway time for calculating a forward gazing distance (Tt×V), V denotes a traveling velocity of the vehicle, φ denotes a yaw angle of the vehicle to the traffic lane, β denotes a radius of curvature of the traffic lane, and X denotes a lateral displacement of the vehicle from a center of the traffic lane; and lateral displacement limit value calculating section that calculates a lateral displacement limit value Xc from a lateral displacement limit value initial value Xc 0 which is a subtraction result of a half of a width L of the traffic lane from a half of a width L 0 of the vehicle and a proportional coefficient Kt which is decreased as a continuation time Tcc of the control executed to avoid the divergence of the vehicle from the traffic lane is increased and wherein the divergence tendency determining section determines that the divergence of the vehicle from the traffic lane occurs when an absolute value of the future estimated lateral displacement value |XS| is equal to or larger than the lateral displacement limit value Xc.

Claim 21

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section, wherein the driving force controlled variable correcting section corrects the driving force controlled variable in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with an elapse of time from a time at which the control executed to avoid the divergence of the vehicle from the traffic lane is started, wherein the driving force controlled variable calculating section calculates a target yaw moment from a difference between a future estimated lateral displacement of the vehicle with respect to the traffic lane estimated from the travel state of the vehicle detected by the travel state detecting section and a lateral displacement limit value and calculates the driving force controlled variable of each road wheel on the basis of the calculated target yaw moment, wherein the driving force controlled variable calculating section comprises: a future estimated lateral displacement value calculating section that calculates the future estimated lateral displacement value (XS) as follows: XS=Tt×V×(φ+Tt×V×β)+X, wherein Tt denotes a headway time for calculating a forward gazing distance (Tt×V), V denotes a traveling velocity of the vehicle, φ denotes a yaw angle of the vehicle to the traffic lane, β denotes a radius of curvature of the traffic lane, and X denotes a lateral displacement of the vehicle from a center of the traffic lane; and lateral displacement limit value calculating section that calculates a lateral displacement limit value Xc from a lateral displacement limit value initial value Xc 0 which is a subtraction result of a half of a width L of the traffic lane from a half of a width L 0 of the vehicle and a proportional coefficient Kt which is decreased as a continuation time Tcc of the control executed to avoid the divergence of the vehicle from the traffic lane is increased and wherein the divergence tendency determining section determines that the divergence of the vehicle from the traffic lane occurs when an absolute value of the future estimated lateral displacement value |XS| is equal to or larger than the lateral displacement limit value Xc.

Claim 22

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section, wherein the driving force controlled variable correcting section corrects the driving force controlled variable in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with an elapse of time from a time at which the control executed to avoid the divergence of the vehicle from the traffic lane is started, wherein the driving force controlled variable calculating section calculates a target yaw moment from a difference between a future estimated lateral displacement of the vehicle with respect to the traffic lane estimated from the travel state of the vehicle detected by the travel state detecting section and a lateral displacement limit value and calculates the driving force controlled variable of each road wheel on the basis of the calculated target yaw moment, wherein the driving force controlled variable calculating section comprises: a future estimated lateral displacement value calculating section that calculates the future estimated lateral displacement value (XS) as follows: XS=Tt×V×(φ+Tt×V×β)+X, wherein Tt denotes a headway time for calculating a forward gazing distance (Tt×V), V denotes a traveling velocity of the vehicle, φ denotes a yaw angle of the vehicle to the traffic lane, β denotes a radius of curvature of the traffic lane, and X denotes a lateral displacement of the vehicle from a center of the traffic lane; and lateral displacement limit value calculating section that calculates a lateral displacement limit value Xc from a lateral displacement limit value initial value Xc 0 which is a subtraction result of a half of a width L of the traffic lane from a half of a width L 0 of the vehicle and a proportional coefficient Kt which is decreased as a continuation time Tcc of the control executed to avoid the divergence of the vehicle from the traffic lane is increased and wherein the divergence tendency determining section determines that the divergence of the vehicle from the traffic lane occurs when an absolute value of the future estimated lateral displacement value |XS| is equal to or larger than the lateral displacement limit value Xc, wherein the driving force controlled variable correcting section further comprises: a target yaw moment calculating section that calculates a target yaw moment Ms as follows: Ms=−K 1 ×K 2 ×(XS−Xc), wherein K 1 denotes a first proportional coefficient determined according to a vehicular specification and K 2 denotes a second proportional coefficient set in accordance with the travel velocity V of the vehicle, when the divergence determining section determines that the tendency of the divergence of the vehicle from the traffic lane occurs; and a target brake fluid pressure calculating section that calculates a target brake fluid pressure Psi for each road wheel according to a magnitude |Ms| of the target yaw moment.

Claim 23

A lane keep control apparatus for an automotive vehicle, comprising: a travel state detecting section that detects a travel state of the vehicle; a divergence tendency determining section that determines whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting section; a driving force controlled variable calculating section that calculates a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting section, the driving force controlled variable calculating section comprising a driving force controlled variable correcting section that corrects the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and a driving force controlling section that controls a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating section, wherein the driving force controlled variable correcting section corrects the driving force controlled variable in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with an elapse of time from a time at which the control executed to avoid the divergence of the vehicle from the traffic lane is started, wherein the driving force controlled variable calculating section calculates a target yaw moment from a difference between a future estimated lateral displacement of the vehicle with respect to the traffic lane estimated from the travel state of the vehicle detected by the travel state detecting section and a lateral displacement limit value and calculates the driving force controlled variable of each road wheel on the basis of the calculated target yaw moment, wherein the driving force controlled variable calculating section comprises: a future estimated lateral displacement value calculating section that calculates the future estimated lateral displacement value (XS) as follows: XS=Tt×V×(φ+Tt×V×β)+X, wherein Tt denotes a headway time for calculating a forward gazing distance (Tt×V), V denotes a traveling velocity of the vehicle, φ denotes a yaw angle of the vehicle to the traffic lane, β denotes a radius of curvature of the traffic lane, and X denotes a lateral displacement of the vehicle from a center of the traffic lane; and lateral displacement limit value calculating section that calculates a lateral displacement limit value Xc from a lateral displacement limit value initial value Xc 0 which is a subtraction result of a half of a width L of the traffic lane from a half of a width L 0 of the vehicle and a proportional coefficient Kt which is decreased as a continuation time Tcc of the control executed to avoid the divergence of the vehicle from the traffic lane is increased and wherein the divergence tendency determining section determines that the divergence of the vehicle from the traffic lane occurs when an absolute value of the future estimated lateral displacement value |XS| is equal to or larger than the lateral displacement limit value Xc, wherein the driving force controlled variable correcting section further comprises: a target yaw moment calculating section that calculates a target yaw moment Ms as follows: Ms=−K 1 ×K 2 ×(XS−Xc), wherein K 1 denotes a first proportional coefficient determined according to a vehicular specification and K 2 denotes a second proportional coefficient set in accordance with the travel velocity V of the vehicle, when the divergence determining section determines that the tendency of the divergence of the vehicle from the traffic lane occurs; and a target brake fluid pressure calculating section that calculates a target brake fluid pressure Psi for each road wheel according to a magnitude |Ms| of the target yaw moment.

Claim 24

A lane keep control method for an automotive vehicle, comprising: detecting a travel state of the vehicle; determining whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the detected travel state; calculating a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the detected travel state; correcting the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and controlling a driving force of each road wheel in accordance with the corrected driving force controlled variable.

Claim 25

A lane keep control method for an automotive vehicle, comprising: detecting a travel state of the vehicle; determining whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the detected travel state; calculating a driving force controlled variable for each road wheel to develop a yaw moment in a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the detected travel state; correcting the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and controlling a driving force of each road wheel in accordance with the corrected driving force controlled variable.

Claim 26

A lane keep control apparatus for an automotive vehicle, comprising: travel state detecting means for detecting a travel state of the vehicle; divergence tendency determining means for determining whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting means; driving force controlled variable calculating means for calculating a driving force controlled variable for each road wheel to develop a yaw moment in such a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting means, the driving force controlled variable calculating means comprising driving force controlled variable correcting means for correcting the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and driving force controlling means for controlling a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating means.

Claim 27

A lane keep control apparatus for an automotive vehicle, comprising: travel state detecting means for detecting a travel state of the vehicle; divergence tendency determining means for determining whether a tendency of a divergence of the vehicle from a traffic lane on which the vehicle is traveling occurs according to the travel state detected by the travel state detecting means; driving force controlled variable calculating means for calculating a driving force controlled variable for each road wheel to develop a yaw moment in such a direction in which the divergence of the vehicle from the traffic lane is avoided in accordance with the travel state detected by the travel state detecting means, the driving force controlled variable calculating means comprising driving force controlled variable correcting means for correcting the driving force controlled variable of each road wheel in such a manner that the yaw moment developed in the direction in which the divergence of the vehicle from the traffic lane is avoided is increased in accordance with a history of a control executed to avoid the divergence of the vehicle from the traffic lane; and driving force controlling means for controlling a driving force of each road wheel in accordance with the driving force controlled variable calculated by the driving force controlled variable calculating means.