JP2007168694A - Traveling controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure favorable traveling performance, particularly, favorable linear traveling performance of a vehicle even when there is a fixing malfunction in a roll rigidity varying means by applying a yaw moment to the vehicle so as to suppress deviation of the vehicle. <P>SOLUTION: When a fixing malfunction occurs in an active stabilizer device 16 of a front wheel side (S20), a target yaw moment Mt is calculated, necessary for coping with an excessive yaw moment caused by roll steer of left and right front wheels 10FL and 10FR and acting on the vehicle (S30). When a fixing malfunction occurs in an active stabilizer device 18 of a rear wheel side (S40), a target yaw moment Mt is calculated, necessary for coping with an excessive yaw moment caused by roll steer of left and right rear wheels 10RL, 10RR and acting on the vehicle. Braking/driving force is controlled such that the yaw moment necessary for coping with the excessive yaw moment acting on the vehicle is applied to the vehicle (S80, 90). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle travel control device, and more specifically, a vehicle travel control device having roll stiffness variable means for changing the roll stiffness of a vehicle and braking / driving force applying means for applying braking / driving force to wheels. Concerning.

As one of the traveling control devices for vehicles such as automobiles, for example, as described in Patent Document 1 below, an active stabilizer device having a two-divided stabilizer and an actuator that relatively rotates the torsion bar of the stabilizer is provided. 2. Description of the Related Art A traveling control device that controls the roll rigidity of a vehicle by rotating the left and right torsion bars relative to each other with an actuator when the vehicle turns is conventionally known.
JP 2005-96672 A

  In general, the active stabilizer device changes the roll rigidity of the vehicle by relatively rotating the left and right torsion bars by the actuator. For example, the actuator is operated in a state where the left and right torsion bars are relatively rotated while the vehicle is turning. When an abnormality that cannot be driven occurs, the left and right torsion bars are rotated relative to each other by a certain angle, that is, in a fixed state. Therefore, when the vehicle goes straight, one of the left and right wheels is in a bound state and the other wheel is in a rebound state. The degree of the bound and rebound state is proportional to the relative rotation angle of the left and right torsion bars that are fixed.

  Further, in general, in a vehicle such as an automobile, the wheel is supported by a suspension arm that is pivotally supported by the vehicle body at one end and pivotally attached to a wheel support member at the other end. In other words, a roll steer occurs. This roll steer occurs only momentarily during normal driving of the vehicle, but if the bounce and rebound state of the wheel continues, the vehicle will change the toe of the wheel due to the roll steer even if the driver tries to drive the vehicle straight. Deflect in the direction.

  However, in the conventional traveling control device as described above for controlling the active stabilizer device, the roll steer accompanying the adhering of the active stabilizer device and countermeasures have not been sufficiently studied. In the control device, when the active stabilizer device is fixed, it is inevitable that the running performance of the vehicle, particularly the straight running performance, is deteriorated due to the roll steer of the wheels.

  The problem of the sticking of the active stabilizer device is not limited to the electric active stabilizer device in which the actuator includes the electric motor and the reduction gear mechanism, and similarly occurs in the hydraulic active stabilizer device in which the actuator is operated by hydraulic pressure. Further, the same problem may occur when the roll stiffness varying means is an active suspension that varies the spring force of the suspension spring.

  The present invention has been made in view of the above-described problems in a conventional vehicle travel control device that controls roll stiffness variable means such as an active stabilizer device, and the main problem of the present invention is that the roll stiffness is variable. Focusing on the fact that the vehicle deflects when a sticking abnormality occurs in the means, and by applying a yaw moment to the vehicle so as to suppress the deflection of the vehicle, even if a sticking abnormality occurs in the roll stiffness variable means, It is to ensure running performance, particularly good straight running performance.

  According to the present invention, the main problem described above is the vehicle having the structure of claim 1, that is, the roll stiffness varying means for changing the roll stiffness of the vehicle, and the braking / driving force applying means for applying the braking / driving force to the wheels. In the steering control device for a vehicle, when a sticking abnormality in which the roll stiffness of the vehicle varies depending on the roll direction of the vehicle occurs in the roll stiffness varying means, the vehicle is based on the deviation amount of the roll stiffness of the vehicle with respect to the roll direction of the vehicle. A vehicle having control means for calculating a yaw moment necessary to counter an extra yaw moment acting on the vehicle and controlling a braking / driving force difference between the left and right wheels so as to apply the necessary yaw moment to the vehicle This is achieved by the travel control device.

  According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claim 1, the roll stiffness variable means includes a front wheel side roll stiffness variable means and a rear wheel side roll stiffness variable means. And the control means is based on which of the front wheel side roll stiffness variable means and the rear wheel side roll stiffness variable means has occurred and the amount of deviation of the roll stiffness of the vehicle relative to the roll direction of the vehicle. It is comprised so that the said required yaw moment may be calculated (structure of Claim 2).

  According to the present invention, in order to effectively achieve the above-mentioned main problems, in the configuration of the above-described claim 1 or 2, the control means is more necessary when the vehicle speed is high than when the vehicle speed is low. The necessary yaw moment is calculated so as to increase the magnitude of the correct yaw moment (configuration of claim 3).

  According to the present invention, in order to effectively achieve the main problems described above, in the configuration of the above-described claims 1 to 3, the control means is a vehicle when the magnitude of the lateral force index value of the vehicle is large. The required yaw moment is calculated so that the required yaw moment is smaller than when the lateral force index value is small.

  According to the present invention, in order to effectively achieve the main problems described above, in the configuration of the first to fourth aspects, the roll stiffness varying means is configured to make the two-part stabilizer and the torsion bar of the stabilizer relative to each other. An active stabilizer having a rotating actuator, wherein the control means is configured to calculate the necessary yaw moment based on a relative rotation angle of the actuator.

  According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claims 1 to 5, the control means controls the target of the vehicle based on the braking / driving operation amount of the driver. Calculating the driving force, calculating the target braking force of each wheel and the target driving force of the vehicle necessary to make the vehicle's braking / driving force the target braking / driving force while applying the necessary yaw moment to the vehicle, The braking force of each wheel is controlled based on the target braking force, and the driving force of the vehicle is controlled based on the target driving force.

  According to the first aspect of the present invention, when there is an abnormality in the roll stiffness varying means in which the roll stiffness of the vehicle differs depending on the roll direction of the vehicle, based on the deviation amount of the roll stiffness of the vehicle with respect to the roll direction of the vehicle. The yaw moment required to counter the extra yaw moment acting on the vehicle is calculated, and the difference in braking / driving force between the left and right wheels is controlled so that the necessary yaw moment is applied to the vehicle. As a result, it is possible to reliably reduce unnecessary yaw moment of the vehicle as compared with the case where the vehicle is not controlled. Driving performance can be ensured.

  Also, in general, the magnitude of the extra yaw moment acting on the vehicle due to the roll steer due to the abnormal sticking of the front wheel side roll stiffness varying means is caused by the roll steer due to the abnormal sticking of the rear wheel side roll stiffness varying means. Since it is larger than the size of the extra yaw moment that acts, it can counter the extra yaw moment acting on the vehicle depending on whether the sticking abnormality occurs in the front wheel side roll stiffness varying means or the rear wheel side roll stiffness varying means. The required yaw moment is also different.

  According to the configuration of the second aspect, based on whether the sticking abnormality occurs in either the front wheel side roll stiffness varying means or the rear wheel side roll stiffness varying means and the deviation amount of the vehicle roll stiffness with respect to the vehicle roll direction. When the yaw moment necessary to counter the excess yaw moment acting on the vehicle is calculated, it is not considered whether the sticking abnormality occurs in the front wheel side roll stiffness variable means or the rear wheel side roll stiffness variable means As compared with this, the yaw moment necessary to counter the extra yaw moment acting on the vehicle can be appropriately calculated.

  In general, in a situation in which roll steer occurs due to abnormal fixation of the roll stiffness varying means, the magnitude of the extra yaw moment acting on the vehicle increases as the vehicle speed increases, and the magnitude of the necessary yaw moment varies depending on the vehicle speed.

  According to the third aspect of the present invention, when the vehicle speed is high, the necessary yaw moment is calculated so that the magnitude of the necessary yaw moment is larger than when the vehicle speed is low. Thus, the yaw moment necessary to counter the extra yaw moment acting on the vehicle can be appropriately calculated.

  Further, as will be described in detail later, when a sticking abnormality occurs in the roll stiffness variable means, the ground contact load of the left and right wheels also changes, and this change in the ground load is the magnitude of the deviation of the roll stiffness of the vehicle relative to the roll direction of the vehicle. However, the influence of the change in the ground load on the turning of the vehicle increases as the lateral acceleration during turning increases. In addition, regardless of the turning direction of the vehicle, if a change in the ground load occurs due to abnormal fixation of the roll stiffness varying means, the lateral force of the turning outer wheel during turning increases the yaw moment against the excess yaw moment acting on the vehicle. Therefore, the magnitude of the yaw moment required to counter the extra yaw moment acting on the vehicle may be smaller as the magnitude of the lateral acceleration during turning is larger.

  According to the fourth aspect of the present invention, when the lateral force index value of the vehicle is large, the necessary yaw moment is larger than when the lateral force index value of the vehicle is small. Since the necessary yaw moment is calculated, the yaw moment necessary to counter the extra yaw moment acting on the vehicle is properly calculated compared to the case where the magnitude of the lateral force index value is not considered. can do.

  According to the fifth aspect of the present invention, the roll stiffness varying means is an active stabilizer having a two-divided stabilizer and an actuator that relatively rotates the torsion bar of the stabilizer, and acts on the vehicle based on the relative rotation angle of the actuator. Since the yaw moment necessary to counter the extra yaw moment is calculated, the yaw moment required to counter the extra yaw moment acting on the vehicle can be calculated easily and accurately.

  According to the sixth aspect of the present invention, the target braking / driving force of the vehicle is calculated based on the braking / driving operation amount of the driver, the necessary yaw moment is applied to the vehicle, and the braking / driving force of the vehicle is set to the target braking / driving. The target braking force of each wheel and the target driving force of the vehicle necessary for making the force are calculated, the braking force of each wheel is controlled based on the target braking force, and the driving force of the vehicle is calculated based on the target driving force. Because it is controlled, the necessary yaw moment can be reliably applied to the vehicle, and the braking / driving force of the vehicle is reliably controlled to the target braking / driving force even in the situation where the necessary yaw moment is applied. be able to.

[Preferred embodiment of problem solving means]
According to one preferable aspect of the present invention, in the configuration of the above first to sixth aspects, the roll stiffness varying means is configured to include an active stabilizer device or an active suspension device (preferred embodiment 1).

  According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 1, the active stabilizer device includes a front wheel side active stabilizer device and a rear wheel side active stabilizer device (preferably). Aspect 2).

  According to another preferred aspect of the present invention, in the configuration of the above-mentioned claims 2 to 6 or the preferred aspect 1 or 2, the front-wheel-side roll stiffness variable means and the rear-wheel-side roll stiffness variable means are fixed to one of them. When an abnormality has occurred, the control of the other roll stiffness variable means is configured to be stopped (preferred aspect 3).

  According to another preferred aspect of the present invention, the rear wheel-side roll stiffness variable means in the configuration of the above-mentioned claims 2 to 6 or the preferred embodiments 1 to 3 is seen with respect to the same roll stiffness deviation amount. The magnitude of the yaw moment required when a sticking abnormality has occurred is configured to be smaller than the magnitude of the yaw moment required when a sticking abnormality has occurred in the front wheel side roll stiffness variable means (preferably Aspect 4).

  According to another preferred embodiment of the present invention, in the configuration of the above-mentioned claims 4 to 6 or the preferred embodiments 1 to 4, the index value of the turning lateral force of the vehicle is configured to be the lateral acceleration of the vehicle. (Preferred embodiment 5)

  According to another preferred aspect of the present invention, in the configuration of the above-mentioned claims 1 to 6 or the preferred aspects 1 to 5, the control means is a target braking / driving of the vehicle based on the braking / driving operation amount of the driver. The force is calculated, the target braking / driving force difference between the left and right wheels is calculated based on the required yaw moment, and the braking / driving force difference between the left and right wheels is set to the target braking / driving force difference. The target braking force of each wheel and the target driving force of the vehicle are calculated to control the braking force of each wheel based on the target braking force of each wheel, and the vehicle is driven based on the target driving force of the vehicle. Configured to control force (preferred embodiment 6).

  According to another preferred embodiment of the present invention, in the configuration of the above-described claims 1 to 6 or the preferred embodiments 1 to 6, the necessary yaw moment is the amount of deviation of the roll stiffness of the vehicle with respect to the roll direction of the vehicle. It is configured so as to be set in advance based on the relationship between the roll amount of the vehicle and the relationship between the roll amount of the vehicle and the roll steer of the wheel when the vehicle is traveling straight ahead (preferable aspect 7).

  The present invention will now be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing one embodiment of a vehicle travel control device according to the present invention applied to a rear wheel drive vehicle in which an active stabilizer device is provided on the front wheel side and the rear wheel side.

  In FIG. 1, 10 FL and 10 FR respectively indicate left and right front wheels that are driven wheels of the vehicle 12, and 10 RL and 10 RR respectively indicate left and right rear wheels that are drive wheels of the vehicle 12. The left and right front wheels 10FL and 10FR, which are also steered wheels, are driven in response to a steering wheel not shown in the drawing by the driver being steered by the driver by a power steering device not shown in the drawing. Steered through tie rods.

  An active stabilizer device 16 is provided between the left and right front wheels 10FL and 10FR, and an active stabilizer device 18 is provided between the left and right rear wheels 10RL and 10RR. The active stabilizer device 16 is integrally connected to a pair of torsion bar portions 16TL and 16TR extending coaxially with each other along an axis extending in the lateral direction of the vehicle, and to the outer ends of the torsion bar portions 16TL and 16TR, respectively. And a pair of arm portions 16AL and 16AR. The torsion bar portions 16TL and 16TR are supported by a vehicle body not shown in the drawing via brackets not shown in the drawing so as to be rotatable around their own axes. The arm portions 16AL and 16AR extend in the longitudinal direction of the vehicle so as to intersect the torsion bar portions 16TL and 16TR, respectively, and the outer ends of the arm portions 16AL and 16AR are respectively left and right through rubber bush devices not shown in the drawing. The front wheels 10FL and 10FR are connected to wheel support members or suspension arms.

  The active stabilizer device 16 has an actuator 20F between the torsion bar portions 16TL and 16TR. The actuator 20F rotates the pair of torsion bar portions 16TL and 16TR in opposite directions as necessary, so that when the left and right front wheels 10FL and 10FR bounce and rebound in opposite phases, the wheel bounces due to torsional stress. Then, the force to suppress rebound is changed, thereby increasing or decreasing the anti-roll moment applied to the vehicle at the position of the left and right front wheels, and variably controlling the roll rigidity of the vehicle on the front wheel side.

  Similarly, the active stabilizer device 18 has a pair of torsion bar portions 18TL and 18TR extending coaxially with each other along an axis extending in the lateral direction of the vehicle, and the outer ends of the torsion bar portions 18TL and 18TR, respectively. It has a pair of arm portions 18AL and 18AR connected together. The torsion bar portions 18TL and 18TR are respectively supported by a vehicle body not shown in the drawing via brackets not shown in the drawing so as to be rotatable around their own axes. The arm portions 18AL and 18AR extend in the longitudinal direction of the vehicle so as to intersect the torsion bar portions 18TL and 18TR, respectively, and the outer ends of the arm portions 18AL and 18AR are respectively left and right through rubber bushing devices not shown in the drawing. The rear wheels 10RL and 10RR are connected to wheel support members or suspension arms.

  The active stabilizer device 18 has an actuator 20R between the torsion bar portions 18TL and 18TR. The actuator 20R rotates the pair of torsion bar portions 18TL and 18TR in directions opposite to each other as necessary, so that when the left and right rear wheels 10RL and 10RR bounce and rebound in opposite phases, the torsional stress causes the wheel By changing the force to suppress bounce and rebound, the anti-roll moment applied to the vehicle at the positions of the left and right rear wheels is increased or decreased, and the roll rigidity of the vehicle on the rear wheel side is variably controlled.

  The active stabilizer devices 16 and 18 themselves do not form the gist of the present invention, and may have any configuration known in the art as long as the roll rigidity of the vehicle can be variably controlled. However, for example, the active stabilizer device described in Japanese Patent Application Laid-Open No. 2005-88722 according to the application of the present applicant, that is, an electric motor having a rotating shaft fixed to the inner end of one torsion bar portion and having a drive gear attached thereto, A driven gear fixed to the inner end of the other torsion bar portion and meshed with the drive gear. The drive gear and the driven gear transmit the rotation of the drive gear to the driven gear, but the rotation of the driven gear is transmitted to the drive gear. It is preferable that the active stabilizer device be a gear that does not.

  Further, as shown in FIG. 1, the braking force of the left and right front wheels 10FL, 10FR and the left and right rear wheels 10RL, 10RR is applied by the hydraulic circuit 30 of the braking device 28 to the braking pressures of the corresponding wheel cylinders 32FL, 32FR, 32RL, 32RR. It is controlled by controlling. Although not shown in the drawing, the hydraulic circuit 30 includes a reservoir, an oil pump, various valve devices, etc., and the braking pressure of each wheel cylinder is normally determined by the amount of depression of the brake pedal 34 and the depression of the brake pedal 34 by the driver. Is controlled according to the pressure of the master cylinder 36 driven according to the control, and is controlled regardless of the depression amount of the brake pedal 34 by the driver by controlling the oil pump and various valve devices as necessary. The

  As shown in FIG. 1, the actuators 20 F and 20 R of the active stabilizer devices 16 and 18, the oil pump of the braking device 28, various valve devices, and the engine 40 are controlled by an electronic control device 50. Although not shown in detail in FIG. 1, the electronic control unit 50 includes a CPU, a ROM, a RAM, and an input / output port device, which are connected to each other by a bidirectional common bus and a drive circuit. It may be better.

  As shown in FIG. 1, the electronic controller 50 includes a signal indicating the vehicle speed V from the vehicle speed sensor 52, a signal indicating the lateral acceleration Gy of the vehicle from the lateral acceleration sensor 54, and the actuator detected by the rotation angle sensors 56F and 56R. Signals indicating the actual rotation angles φf and φr of 20F and 20R are input. Further, the electronic control unit 50 corresponds to a signal indicating the accelerator opening φ detected by an accelerator opening sensor 60 provided on the accelerator pedal 58, a signal indicating the master cylinder pressure Pm from the pressure sensor 62, and pressure sensors 64FL to 64RR. A signal indicating the braking pressure (wheel cylinder pressure) Pbi (i = fl, fr, rl, rr) of the wheel is input. The lateral acceleration sensor 54 and the rotational angle sensors 56F and 56R detect the lateral acceleration Gy and the rotational angles φf and φr of the vehicle with positive values generated when the vehicle turns left.

  Although the electronic control unit 50 is not shown in the flowchart, the active stabilizer device 16 and the electronic control unit 16 are determined by determining whether the rotation angles φf and φr of the actuators 20F and 20R become the corresponding target rotation angles φft and φrt, respectively. It is determined whether 18 is normal.

  The electronic control unit 50 estimates the roll moment acting on the vehicle based on the lateral acceleration Gy of the vehicle and calculates the target roll stiffness of the front and rear wheels during normal turning when the active stabilizer devices 16 and 18 are normal. Based on the roll moment and the target roll stiffness, the target rotation angles φft and φrt of the actuators 20F and 20R of the active stabilizer devices 16 and 18 are calculated to increase the anti-roll moment in the direction to cancel the moment, and the rotation angles of the actuators 20F and 20R are calculated. Control is performed so that φf and φr correspond to the corresponding target rotation angles φft and φrt, respectively, thereby reducing the roll of the vehicle when turning.

  On the other hand, when the fixing abnormality in which the rotation angles φf and φr of the actuator 20F or 20R do not change occurs in any of the active stabilizer devices 16 and 18, the electronic control device 50 stops the control of the active stabilizer device and is normal. After the rotation angle φf and φr of the actuator 20F or 20R of the active stabilizer device 16 or 18 is gradually reduced and the rotation angle becomes zero, the normal active stabilizer device 16 or 18 is also controlled. Cancel.

  Further, the electronic control unit 50 is a method known in the art based on the accelerator opening φ and the master cylinder pressure Pm detected by the accelerator opening sensor 60 during normal operation of the active stabilizer devices 16 and 18. To calculate the target braking / driving force Fvt of the vehicle, and when the target braking / driving force Fvt is the driving force, the target throttle opening φt of the engine 40 is calculated based on the accelerator opening φ, and the target throttle opening φt Based on this, the engine 40 is controlled.

  Further, the electronic control unit 50 has a predetermined pressure increase coefficient Ki (i = fl, i) when the active braking devices 16 and 18 are normally operated and the target braking / driving force Fvt is a braking force. A value obtained by multiplying fr, rl, rr) is calculated as a target braking pressure Pti (i = fl, fr, rl, rr) of each wheel, and control is performed so that the braking pressure Pi becomes the corresponding target braking pressure Pti.

  On the other hand, when there is a sticking abnormality in the active stabilizer devices 16 and 18, the electronic control unit 50 causes the rotation angle φf, φr, vehicle speed V, vehicle speed of the actuator 20F or 20R of the active stabilizer device 16 or 18 in which the sticking abnormality occurs. Based on the lateral acceleration Gy, the yaw moment Mt required to give the vehicle a yaw moment that opposes the extra yaw moment acting on the vehicle is calculated. The yaw moment Mt is calculated as a moment whose direction is opposite to that of the extra yaw moment and whose magnitude is the same or smaller than that of the extra yaw moment.

  The electronic control unit 50 calculates the target braking force Fbti of each wheel and the target driving force Fvdt of the vehicle for achieving the target braking / driving force Fvt and the yaw moment Mt, and the target braking of each wheel based on the target braking force Fbti. The pressure Pti is calculated and controlled so that the braking pressure Pi becomes the corresponding target braking pressure Pti, and the target throttle opening φt of the engine 40 is calculated based on the target driving force Fvdt, and based on the target throttle opening φt. The engine 40 is controlled.

  The control of the active stabilizer device, the control of the braking force, and the control of the engine in the case where the active stabilizer devices 16 and 18 are normal do not form the gist of the present invention. It may be carried out in any known manner.

  Next, a change in the behavior of the vehicle when a sticking abnormality occurs in the active stabilizer device 16 on the front wheel side and the active stabilizer device 18 on the rear wheel side when the vehicle turns will be described. The left and right front wheels 10FL and 10FR steer in the toe-in direction when bound, and steer in the toe-out direction when rebounded, and the left and right rear wheels 10RL and 10RR steer in the toe-out direction when bound and enter the toe-in direction when rebounded. Steer changes.

  In particular, when an abnormality occurs in the front wheel side active stabilizer device 16 when the vehicle turns left, as shown in FIG. 4A, the left front wheel 10FL bounces and the right front wheel 10FR rebounds when the vehicle travels straight. Therefore, as shown in FIG. 4B, the left front wheel 10FL is steered in the toe-in direction and the right front wheel 10FR is steered in the toe-out direction. Even when the vehicle is operated to the straight traveling position, an excessive yaw moment Ma in the right turning direction acts on the vehicle 12, and the vehicle is deflected in the right turning direction. Therefore, the necessary yaw moment Mt is the yaw moment in the left turn direction, and the necessary yaw moment Mt increases as the vehicle speed V increases.

  When the left front wheel 10FL bounces and the vehicle turns left with the right front wheel 10FR rebounded, the left front wheel 10FL, which is the turning inner wheel, is compared with the case where the active stabilizer device 16 on the front wheel side is normal. However, since the contact load of the right front wheel 10FR, which is a turning outer wheel, increases, the magnitude of the yaw moment Mt in the left turning direction necessary to counter the excess yaw moment Ma may be small.

  Conversely, when the vehicle turns to the right with the left front wheel 10FL bound and the right front wheel 10FR rebounded, the right which is the turning inner wheel, compared to the case where the active stabilizer device 16 on the front wheel side is normal. Although the ground load on the front wheel 10FR increases, the ground load on the left front wheel 10FL, which is a turning outer wheel, decreases. In this case as well, the magnitude of the yaw moment Mt in the left turn direction necessary to counter the extra yaw moment Ma is increased. Can be small.

  On the other hand, if a sticking abnormality occurs in the active stabilizer device 18 on the rear wheel side when the vehicle turns left, the left rear wheel 10RL bounces as shown in FIG. As shown in FIG. 5B, the left rear wheel 10RL is steered in the toe-out direction and the right rear wheel 10RR is steered in the toe-in direction. Even if the person operates the steering wheel 14 to the straight traveling position of the vehicle, an excessive yaw moment Ma in the right turning direction acts on the vehicle 12, and the vehicle is deflected in the right turning direction. Therefore, the necessary yaw moment Mt is the yaw moment in the left turn direction, and the necessary yaw moment Mt increases as the vehicle speed V increases.

  Further, when the vehicle turns left with the left rear wheel 10RL bounced and the right rear wheel 10RR rebounded, it is a turning inner wheel as compared with the case where the active stabilizer device 18 on the rear wheel side is normal. Although the ground load on the left rear wheel 10RL decreases, the ground load on the right rear wheel 10RR, which is the outer turning wheel, increases. Therefore, the magnitude of the yaw moment Mt in the left turn direction required to counter the extra yaw moment Ma is It can be small.

  Conversely, when the vehicle turns to the right with the left rear wheel 10RL bounced and the right rear wheel 10RR rebounded, compared to the case where the active stabilizer device 18 on the rear wheel side is normal, the turning inner wheel Although the ground load on the right rear wheel 10RR increases, the ground load on the left rear wheel 10RL, which is a turning outer wheel, decreases. In this case as well, the yaw in the left turning direction necessary to counter the extra yaw moment Ma is required. The magnitude of the moment Mt may be small.

  The relationship between wheel bounce and rebound when the front wheel side active stabilizer device 16 or the rear wheel side active stabilizer device 18 is stuck abnormally when the vehicle turns to the right is active when the vehicle turns left. The relationship is opposite to that in the case where the fixing device has a sticking abnormality. Therefore, the direction of the extra yaw moment Ma and the yaw moment Mt necessary to counter this is also reversed.

  Next, a vehicle travel control routine in the embodiment will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 2 is started by closing an ignition switch not shown in the figure, and is repeatedly executed at predetermined time intervals.

  First, in step 10, signals indicating the actual rotation angles φf and φr of the actuators 20F and 20R detected by the rotation angle sensors 56F and 56R are read. In step 20, the front wheel side active stabilizer is read. It is determined whether or not a sticking abnormality has occurred in the actuator 20F of the device 16. If a negative determination is made, the process proceeds to step 40. If an affirmative determination is made, the process proceeds to step 30.

  In step 30, a graph shown by a solid line in FIG. 3 based on the absolute value of the vehicle lateral acceleration Gy as an index value of the rotational angle φfe, vehicle speed V, and vehicle lateral force of the actuator 20F in the fixed state. From the map corresponding to, the actuator 20F is fixed at the rotation angle φfe, and roll steer is generated in the left and right front wheels 10FL and 10FR, so that the yaw moment necessary to counter the extra yaw moment acting on the vehicle, that is, A vehicle target yaw moment Mt for canceling the influence of roll steer is calculated.

  In step 40, it is determined whether or not a sticking abnormality has occurred in the actuator 20R of the active stabilizer device 18 on the rear wheel side. If an affirmative determination is made, the process proceeds to step 70, where a negative determination is made. Sometimes go to step 50.

  In step 50, control of the active stabilizer device when the front wheel side active stabilizer device 16 and the rear wheel side active stabilizer device 18 are normal is performed. That is, the roll moment acting on the vehicle is estimated based on the lateral acceleration Gy of the vehicle, the target roll stiffness of the front and rear wheels is calculated, and the anti-roll moment in the direction to cancel the roll moment is increased based on the roll moment and the target roll stiffness. The target rotation angles φft and φrt of the actuators 20F and 20R of the active stabilizer devices 16 and 18 are calculated, and the rotation angles φf and φr of the actuators 20F and 20R are controlled to the corresponding target rotation angles φft and φrt, respectively. The roll of the vehicle when turning is reduced.

  In step 60, the target braking / driving force Fvt of the vehicle is calculated based on the accelerator opening φ detected by the accelerator opening sensor 62 and the master cylinder pressure Pm in a manner known in the art. The braking / driving force is controlled to become the target braking / driving force Fvt. That is, when the target braking / driving force Fvt is a driving force, the target throttle opening φt of the engine 40 is calculated based on the accelerator opening φ, and the target braking pressure Pti (i = fl, fr, rl, When rr) is set to 0 and the target braking / driving force Fvt is a braking force, the target throttle opening φt is set to 0 and the master cylinder pressure Pm is set to a predetermined pressure increase coefficient Ki (i = fl, fr , Rl, rr) is calculated as the target braking pressure Pti for each wheel. Then, the engine 40 is controlled based on the target throttle opening φt, and the braking pressure Pi is controlled to become the corresponding target braking pressure Pti.

  In step 70, a graph shown by a broken line in FIG. 3 based on the absolute value of the vehicle lateral acceleration Gy as an index value of the rotation angle φre, the vehicle speed V, and the vehicle lateral force of the actuator 20R in the fixed state. From the map corresponding to, the actuator 20F is fixed at the rotation angle φfe, and roll steer is generated in the left and right front wheels 10FL and 10FR, so that the yaw moment necessary to counter the extra yaw moment acting on the vehicle, that is, A vehicle target yaw moment Mt for canceling the influence of roll steer is calculated.

  In step 80, when the target yaw moment Mt is a positive value as the tread Tf of the front wheel, the target additional braking forces ΔFbtfl and ΔFbtfr of the left and right front wheels and the target additional driving force ΔFvdt of the vehicle are in accordance with the following equations 1-3. When the target yaw moment Mt is a positive value, the target additional braking forces ΔFbtfl, ΔFbtfr of the left and right front wheels and the target additional driving force ΔFvdt of the vehicle are calculated according to the following equations 4-6.

ΔFbtfl = Mt / Tf (1)
ΔFbtfr == 0 (2)
ΔFvdt = Fbtfl (3)
ΔFbtfr = -Mt / Tf (4)
ΔFbtfl == 0 (5)
ΔFvdt = Fbtfr (6)

  In step 90, the target braking / driving force Fvt of the vehicle is calculated in the same manner as in step 60 described above, the target braking / driving force of the vehicle is corrected to Fvt + ΔFvdt, and the corrected target braking / driving force Fvt is obtained. Based on this, the target throttle opening φt of the engine 40 is calculated, and the engine 40 is controlled based on the target throttle opening φt. Further, a value obtained by multiplying the master cylinder pressure Pm by a predetermined pressure increase coefficient Ki is calculated as the target braking pressure Pti of each wheel, and the left and right front wheels calculated based on the target braking / driving force Fvt of the vehicle using Kp as a positive coefficient. The values obtained by adding KpΔFbtfl and KpΔFbtfr to the target braking pressures Ptfl and Ptfr are calculated as the corrected target braking pressures Ptfl and Ptfr for the left and right front wheels, and the braking pressure Pi becomes the corresponding corrected target braking pressure Pti. It is controlled as follows.

  Thus, according to the illustrated embodiment, when both the active stabilizer device 16 on the front wheel side and the active stabilizer device 18 on the rear wheel side are normal, the active when the active stabilizer device is normal in steps 50 and 60. Control of the stabilizer device and control of braking / driving force are performed.

  On the other hand, when there is a sticking abnormality in the actuator 20F of the front wheel side active stabilizer device 16, an affirmative determination is made in step 20, and roll steer occurs in the left and right front wheels 10FL and 10FR in step 30. The target yaw moment Mt required to counter the extra yaw moment acting on the vehicle due to the above is calculated, and the yaw moment necessary to counter the extra yaw moment acting on the vehicle is calculated in steps 80 and 90. The braking / driving force is controlled to be applied to the vehicle.

  Further, when there is a sticking abnormality in the actuator 20R of the active stabilizer device 18 on the rear wheel side, a negative determination is made in step 20, but an affirmative determination is made in step 40, and left and right in step 70. The target yaw moment Mt necessary to counter the extra yaw moment acting on the vehicle due to the occurrence of roll steer in the rear wheels 10RL, 10RR is calculated, and extra steps acting on the vehicle in steps 80 and 90 are calculated. The braking / driving force is controlled so that the yaw moment necessary to counter the yaw moment is applied to the vehicle.

  Therefore, according to the illustrated embodiment, even if a sticking abnormality occurs in any of the active stabilizer device 16 on the front wheel side and the active stabilizer device 18 on the rear wheel side, the deflection of the vehicle due to roll steer can be reliably suppressed. As a result, even when a sticking abnormality occurs in the active stabilizer device, it is possible to ensure good running performance of the vehicle, particularly good straight running performance.

  In addition, according to the illustrated embodiment, an excess yaw moment acting on the vehicle can be countered depending on which of the front wheel side active stabilizer device 16 and the rear wheel side active stabilizer device 18 is stuck abnormally. Since the necessary target yaw moment Mt is calculated to be an optimum value, the necessary target yaw moment is required regardless of whether the front wheel side active stabilizer device 16 or the rear wheel side active stabilizer device 18 is stuck abnormally. Compared with the case where Mt is calculated, vehicle deflection due to roll steer can be appropriately suppressed.

  In particular, according to the illustrated embodiment, the left and right front wheels 10FL and the left and right front wheels 10FL and the rotation angle φfe or φre of the actuator 20F or 20R in the fixed state, the vehicle speed V, and the absolute value of the lateral acceleration Gy of the vehicle as an index value of the lateral force of the vehicle Since the target yaw moment Mt of the vehicle is calculated as the yaw moment necessary to counter the extra yaw moment acting on the vehicle due to the roll steer occurring at 10FR or the left and right rear wheels 10RL, 10RR, the vehicle speed V Compared to the case where the absolute value of the lateral acceleration Gy of the vehicle as an index value of the vehicle lateral force is not taken into account, the target yaw moment Mt can be calculated to an optimum value according to the running state of the vehicle. Thus, the deflection of the vehicle due to roll steer can be appropriately suppressed.

  Further, according to the illustrated embodiment, the deviation amount of the roll stiffness of the vehicle with respect to the roll direction of the vehicle is determined by the rotation angles φfe and φre of the actuators 20F and 20R, and the target yaw moment Mt is calculated based on the rotation angles φfe and φre. Therefore, the yaw moment required to counter the extra yaw moment acting on the vehicle can be calculated easily and accurately.

  Further, according to the illustrated embodiment, the target braking / driving force Fvt of the vehicle is calculated based on the braking / driving operation amount of the driver, and each wheel target for achieving the target braking / driving force Fvt and the necessary yaw moment Mt. Since the braking force Fbti and the vehicle target driving force Fvdt are calculated, the braking force of each wheel is controlled based on the target braking force Fbti, and the output of the engine 40 is controlled based on the target driving force Fvdt. It can be reliably avoided that the braking / driving force of the vehicle does not become the target braking / driving force Fvt due to the application of the yaw moment based on the moment Mt.

  Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the left and right front wheels 10FL and 10FR steer in the toe-in direction when bound, and the steer change in the toe-out direction when rebounded, and the left and right rear wheels 10RL and 10RR steer in the toe-out direction when bound. While changing, it is assumed that the steering changes in the toe-in direction at the time of rebounding. However, the steering change of the wheels accompanying the bounding and rebounding of the wheels may be any change.

  In the above-described embodiment, the actuator 20F or 20R in the fixed state acts on the vehicle based on the rotation angle φfe or φre, the vehicle speed V, and the absolute value of the lateral acceleration Gy of the vehicle as an index value of the lateral force of the vehicle. The target yaw moment Mt of the vehicle is calculated as a yaw moment necessary to counter the excess yaw moment. The vehicle lateral force index value is, for example, the product of the vehicle yaw rate and the vehicle speed, the steering angle. And the vehicle speed may be corrected so that the target yaw moment Mt is calculated without considering the lateral force index value of the vehicle.

  In the above-described embodiment, the vehicle is a rear wheel drive vehicle, and the yaw moment based on the target yaw moment Mt is applied to the vehicle by applying a braking force to one of the left and right front wheels. However, if the vehicle is a front-wheel drive vehicle, the yaw moment based on the target yaw moment Mt may be applied to the vehicle by applying a braking force to one of the left and right rear wheels, and the vehicle is driven four-wheels. In the case of a vehicle, the yaw moment based on the target yaw moment Mt may be applied to the vehicle by applying a braking force to the left front and rear wheels or the right front and rear wheels.

  In the above-described embodiment, the roll stiffness is changed by the active stabilizer devices on the front wheel side and the rear wheel side. However, the roll stiffness variable means is used in the technical field such as an active suspension device. Any known means may be used.

1 is a schematic configuration diagram showing one embodiment of a vehicle travel control device according to the present invention applied to a rear wheel drive vehicle in which an active stabilizer device is provided on a front wheel side and a rear wheel side. FIG. It is a flowchart which shows the traveling control routine of the vehicle in an Example. The actuator rotation angles φfe, φre, the vehicle speed V, the side of the vehicle when the front wheel side active stabilizer device has a sticking abnormality (solid line) and the rear wheel side active stabilizer device has a sticking abnormality (broken line). It is a graph which shows the relationship between the absolute value of acceleration Gy, and the target yaw moment Mt of a vehicle. It is a rear view (A) which shows the bounce and rebound state of a right-and-left front wheel, and a top view showing the situation of roll steer of a right-and-left front wheel about the case where sticking abnormality arises in the active stabilizer device on the front wheel side. It is a rear view (A) which shows the bounce and rebound state of a right-and-left rear wheel, and a top view showing the situation of roll steer of a right-and-left rear wheel about the case where sticking abnormality arises in the active stabilizer device on the rear wheel side.

Explanation of symbols

16, 18 Active stabilizer device 28 Braking device 40 Engine 50 Electronic control device 52 Vehicle speed sensor 54 Lateral acceleration sensor 56F, 56R Rotation angle sensor 62, 64FL-64RL Pressure sensor

Claims (6)

  In a vehicle steering control device having a roll stiffness variable means for changing the roll stiffness of a vehicle and a braking / driving force applying means for applying a braking / driving force to a wheel, the vehicle roll stiffness varies depending on the roll direction of the vehicle. When an abnormality has occurred in the roll stiffness variable means, the yaw moment necessary to counter the extra yaw moment acting on the vehicle is calculated based on the deviation amount of the roll stiffness of the vehicle with respect to the roll direction of the vehicle, A vehicle travel control device comprising control means for controlling a difference in braking / driving force between left and right wheels so as to apply a necessary yaw moment to a vehicle.   The roll stiffness variable means includes a front wheel side roll stiffness variable means and a rear wheel side roll stiffness variable means, and the control means has a sticking abnormality in any of the front wheel side roll stiffness variable means and the rear wheel side roll stiffness variable means. 2. The vehicle travel control device according to claim 1, wherein the necessary yaw moment is calculated based on occurrence of the vehicle and a deviation amount of the roll rigidity of the vehicle relative to the roll direction of the vehicle.   3. The vehicle according to claim 1, wherein the control means calculates the necessary yaw moment so that the magnitude of the necessary yaw moment is larger when the vehicle speed is high than when the vehicle speed is low. Travel control device.   The control means controls the required yaw moment so that the required yaw moment is smaller when the lateral force index value of the vehicle is larger than when the lateral force index value of the vehicle is small. 4. The vehicle travel control device according to claim 1, wherein a moment is calculated.   The roll stiffness variable means is an active stabilizer having a two-divided stabilizer and an actuator that relatively rotates the torsion bar of the stabilizer, and the control means calculates the necessary yaw moment based on a relative rotation angle of the actuator. The vehicle travel control device according to any one of claims 1 to 4, wherein The control means calculates a target braking / driving force of the vehicle based on a braking / driving operation amount of the driver, applies the necessary yaw moment to the vehicle, and sets the braking / driving force of the vehicle to the target braking / driving force. The necessary target braking force of each wheel and the target driving force of the vehicle are calculated, the braking force of each wheel is controlled based on the target braking force, and the driving force of the vehicle is controlled based on the target driving force. The vehicle travel control device according to claim 1, wherein the vehicle travel control device is a vehicle travel control device.

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