JP2002293173A - Vehicle motion control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct travel for obstruction avoidance by operating a vehicle behavior controller properly over total avoidance travel via preliminary detection of an obstruction to a vehicle and in consideration of various pieces of travel information. SOLUTION: If an obstruction is recognized in a travel road ahead, an avoidance travel control part 80 determines whether a vehicle concerned 1 can avoid the obstruction only via a braking operation in consideration of a road surface friction coefficient, road surface information on a road surface gradient and relative motion between the vehicle concerned 1 and the obstruction, and determines a state of avoidance operation of the vehicle concerned 1 to the obstruction. If the vehicle concerned 1 can not avoid the obstruction only via a braking operation, and no avoidance operation of the vehicle concerned 1 is found to the obstruction, a shift is made to an avoidance travel mode according to a steering operation and vehicle behavior. In the avoidance travel mode, a vehicle behavior control part 60, 65, 70 and 75 executes necessary control according to a change in the steering operation and vehicle behavior, and the avoidance travel mode is canceled when the end of the avoidance travel by the driver's steering operation is detected or stable vehicle behavior after the obstruction avoidance is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle motion control device for appropriately performing avoidance of an obstacle in consideration of before and after avoidance.

[0002]

2. Description of the Related Art In recent years, control devices for various vehicle behaviors have been developed and put into practical use in order to improve the running performance of vehicles. A braking force control device that applies braking force to appropriate wheels during cornering to improve running stability based on the relationship between the forces acting on the vehicle during cornering, etc., after controlling the steering of the rear wheels according to the running state of the vehicle Wheel steering control device, left and right driving force distribution control device that controls the distribution of driving force between left and right wheels based on the running condition of the vehicle, and differential limiting force of the center differential device between the front and rear wheels based on the running condition of the vehicle An example is a power distribution control device that performs predetermined torque distribution between front and rear wheels.

[0003] Recently, various techniques have been proposed for recognizing obstacles ahead of a vehicle (including a preceding vehicle) so as to safely stop or avoid the obstacle. For example, JP-A-7-
In Japanese Patent No. 21500, the steering operation of the driver is detected, and the own vehicle and the obstacle are in an approaching state.
Only when it is determined that contact between the host vehicle and an obstacle cannot be avoided only by braking the vehicle by controlling the brake pressure,
There is disclosed an automatic brake control device that controls a brake pressure for each wheel so that the turning performance of a vehicle in a steering wheel operation direction of a driver is enhanced.

[0004]

However, in the above-mentioned prior art, there is a problem that although it is possible to appropriately control the vehicle until the obstacle is avoided, it is not possible to perform detailed control after the vehicle starts to avoid the obstacle.

[0005] In the above-mentioned prior art, the aim is to improve the turning performance by automatic braking. However, it is desirable that the control can be efficiently performed using the above-described control device for various vehicle behaviors. However, when the vehicle avoids an obstacle, an operation to return to the original vehicle posture is performed in a short time when avoiding the obstacle and after avoiding the obstacle. It is necessary to ensure that the control device operates stably and naturally.

Further, when the vehicle enters the avoidance travel, if the avoidance travel is executed depending on the operation condition of the vehicle, the operation of the driver may be hindered and the driver may feel uncomfortable. For example, if the driver wants to actively avoid obstacles by his / her own operation and tries to improve the turning performance by operating the accelerator or the steering wheel, etc. There is a case where the driver's will is hindered by a control change in a direction to improve the performance. Therefore, it is desired that the control for avoiding the obstacle is executed in consideration of such operation and intention of the driver.

The present invention has been made in view of the above circumstances, and determines obstacles to a vehicle in advance, takes into account various driving information, and performs a natural operation without hindering the driver's operation and intention throughout avoiding driving. It is another object of the present invention to provide a vehicle motion control device capable of appropriately operating a control device for each vehicle behavior and appropriately running around an obstacle.

[0008]

According to a first aspect of the present invention, there is provided a vehicle motion control device for recognizing an obstacle ahead of a traveling road and detecting obstacle information. Own vehicle information detecting means for detecting the traveling state of the own vehicle, road surface information estimating means for estimating the road surface information to travel, vehicle behavior control means for controlling the vehicle behavior by varying the turning performance of the own vehicle, Avoidance operation determining means for determining the state of the avoidance operation of the own vehicle with respect to the obstacle; and the own vehicle being operated only by the braking operation of the own vehicle based on the obstacle information, the own vehicle information, and the road surface information. A braking avoidance determining means for determining whether an obstacle can be avoided; and a braking avoidance determining means for determining whether or not the own vehicle is able to avoid the obstacle by only a braking operation and when the own vehicle is not performing an avoiding operation on the obstacle. hand The vehicle behavior control means is shifted to the avoidance travel mode according to the operation and the vehicle behavior, and the control by the vehicle behavior control means in the avoidance travel mode is variable during the avoidance travel mode according to the steering wheel operation and the vehicle behavior. And avoidance control means for performing the control.

[0009] The vehicle motion control device according to claim 1 is
The obstacle recognition means recognizes an obstacle in front of the traveling road to detect obstacle information, the own vehicle information detecting means detects a traveling state of the own vehicle, and the road surface information estimating means estimates road surface information to travel. Also, the braking avoidance determining means determines whether the own vehicle can avoid the obstacle by only the braking operation of the own vehicle based on the obstacle information, the own vehicle information, and the road surface information. The state of the avoidance operation on the object is determined. The avoidance control means controls the vehicle behavior by varying the turning performance of the own vehicle when the own vehicle cannot avoid the obstacle only by the braking operation and when the own vehicle is not performing the avoidance operation on the obstacle. The vehicle behavior control means is shifted to the avoidance traveling mode according to the steering operation and the vehicle behavior. The avoidance control means varies the control by the vehicle behavior control means in the avoidance travel mode in accordance with the steering wheel operation and the vehicle behavior during the avoidance travel mode. For this reason, the obstacles to the vehicle are determined in advance, and the control device of each vehicle behavior is appropriately operated over the entire avoidance traveling in consideration of various traveling information, and the vehicle is appropriately traveling around the obstacle. Can be. In particular, the avoidance driving mode is executed when the avoidance operation for the obstacle of the own vehicle is not performed, so that the control is naturally performed without hindering the operation and intention of the driver.

According to a second aspect of the present invention, there is provided a vehicle motion control apparatus according to the first aspect, wherein the avoidance operation determining means includes at least one of an acceleration operation and a turning operation of the own vehicle. Is determined that the avoidance operation is being performed when is performed. Generally, a braking operation is performed to avoid an obstacle in front of the vehicle.However, in addition, there is a case where the vehicle is accelerated to avoid the obstacle quickly or to avoid the obstacle by operating a steering wheel. Determines that the driver is actively trying to avoid obstacles by his / her own operation, and reliably prevents the control device from unnecessarily interfering with the operation and intention of the driver.

Further, according to a third aspect of the present invention, in the vehicle motion control apparatus according to the second aspect of the present invention, the acceleration operation of the own vehicle includes an accelerator opening, an engine speed, and an engine torque. And at least one of an operation of a traction control unit that controls a driving force transmitted to a road surface in accordance with a longitudinal acceleration and a wheel slip. Specifically, the driver's acceleration operation is accurately determined based on the parameters described above.

According to a fourth aspect of the present invention, in the vehicle motion control apparatus according to the second aspect, the turning operation of the own vehicle is detected by at least one of a steering wheel operation and a parking brake operation. It is characterized by doing. Specifically, by the operation described above,
Accurately judge the turning operation of the driver.

According to a fifth aspect of the present invention, there is provided a vehicle motion control device according to any one of the first to fourth aspects, wherein the avoidance traveling mode by the avoidance control means is the same as that of the first aspect. A first mode in which the vehicle behavior control means is controlled and changed in a direction to improve turning performance more than usual, and a second mode in which control is changed in a direction to maintain the vehicle attitude more strongly than in the first mode. It is characterized by. In the avoidance traveling mode, the control of the vehicle behavior control means is changed in a direction for improving the turning performance more than usual, or the control is changed in a direction for maintaining the vehicle posture stronger than usual, that is, in a direction for further improving the stability.

According to a sixth aspect of the present invention, there is provided a vehicle motion control apparatus according to the fifth aspect, wherein the avoidance traveling mode by the avoidance control means includes setting the vehicle behavior control means to the first vehicle behavior control means. In this mode, when the steering direction of the steering wheel is reversed, the vehicle behavior control means is switched to the second mode. That is, in general, in avoidance traveling, turning properties are required at the beginning of avoidance, but stability is required to return to the original vehicle posture after avoiding an obstacle. For this reason, the reversal of the steering direction of the steering wheel is determined as a branch point of obstacle avoidance during avoidance traveling,
The control that emphasizes turning is changed from the control that emphasizes stability.

According to a seventh aspect of the present invention, there is provided a vehicle motion control device according to any one of the first to sixth aspects, wherein the avoidance traveling mode by the avoidance control means is the same as that of the first aspect. In at least one of the case where the state where the steering wheel steering is small continues for a predetermined time or more, and the state where the deviation between the target yaw rate and the actual yaw rate is within a predetermined setting range continues for a predetermined time or more. The feature is to release the avoidance driving mode. That is, if the state where the steering wheel steering is small continues for a predetermined time or longer, or if the state where the deviation between the target yaw rate and the actual yaw rate is within a predetermined set range continues for a predetermined time or longer, the avoidance traveling ends. The avoidance driving mode is cancelled.

Further, the vehicle motion control device according to the present invention as set forth in claim 8 is the vehicle motion control device according to any one of claims 1 to 7, wherein the vehicle behavior control means includes:
A braking force control unit that controls the braking force to be applied to predetermined selected wheels based on the running state of the vehicle, a rear wheel steering control unit that performs predetermined steering control of the rear wheels according to the running state of the vehicle, At least a front / rear driving force distribution control unit that variably controls the driving force distribution between the front and rear wheels according to the traveling state and a left / right driving force distribution control unit that variably controls the driving force distribution between the left and right wheels according to the traveling state of the vehicle It is characterized by one.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show an embodiment of the present invention, FIG. 1 is a schematic explanatory view of the entire vehicle motion control device in a vehicle, FIG. 2 is a functional block diagram illustrating an avoidance traveling control unit, and FIG. 4 is a flowchart continued from FIG. 3, FIG. 5 is a flowchart continued from FIG. 4, and FIG. 6 is a flowchart continued from FIG.

In FIG. 1, reference numeral 1 denotes a host vehicle, and reference numeral 2 denotes an engine, which is arranged at the front of the vehicle. The driving force from the engine 2 is transmitted from an automatic transmission (including a torque converter and the like) 3 behind the engine 2 to a center differential device 4 via a transmission output shaft 3a. The torque is distributed to the rear wheel side and the front wheel side at a predetermined torque distribution ratio.

The driving force distributed from the center differential device 4 to the rear wheels is input to a rear final drive device 8 via a rear drive shaft 5, a propeller shaft 6, and a drive pinion 7.

On the other hand, the driving force distributed from the center differential device 4 to the front wheels is transferred to the front differential device 12 via the transfer drive gear 9, the transfer driven gear 10, and the front drive shaft 11.
It is configured to be inputted to. Here, the automatic transmission 3, the center differential device 4, the front differential device 12, and the like are integrally provided in a case 13.

The driving force input to the rear final drive device 8 is applied to the left rear wheel 1 via the rear wheel left drive shaft 14rl.
5rl, right rear wheel 15rr via rear wheel right drive shaft 14rr
Is transmitted to On the other hand, the front differential device 1
2 is transmitted to the left front wheel 15fl via the front left drive shaft 14fl and to the right front wheel 15fr via the front right drive shaft 14fr.

The center differential device 4 is provided at the rear inside the case 13, and the transmission output shaft 3a is rotatably inserted from the front of the rotatably stored carrier 16, while the rear drive shaft 5 is mounted from the rear. It is inserted rotatably.

A large-diameter first sun gear 17 is mounted on the rear end of the input-side transmission output shaft 3a, and a small-diameter first sun gear 17 is mounted on the front end of the rear drive shaft 5 that outputs power to the rear wheels. The second sun gear 18 is mounted on the shaft, and the carrier 16
A first sun gear 17 and a second sun gear 18 are housed therein.

The first sun gear 17 is a small-diameter first sun gear.
And a second gear train is formed by meshing the second sun gear 18 with a large-diameter second pinion 20. First pinion 19
The second pinion 20 and the second pinion 20 are integrally formed, and a plurality of pairs (for example, three pairs) of pinions are rotatably supported by the carrier 16. The carrier 16 is connected to the transfer drive gear 9 at the front end.
6 to the front wheels.

That is, in the center differential device 4, the driving force from the transmission output shaft 3a is transmitted to the first sun gear 17, and is output from the second sun gear 18 to the rear drive shaft 5, and the transmission drive gear 9. A compound planetary gear system without a ring gear for outputting to the front drive shaft 11 via the transfer driven gear 10.

The compound planetary gear type center differential device 4 includes first and second sun gears 17 and 18 and a plurality of first and second pinions 19 and 20 arranged around the sun gears 17 and 18. By properly setting the number of teeth, a differential function is provided.

Also, by appropriately setting the radius of the engagement pitch circle between the first and second sun gears 17 and 18 and the first and second pinions 19 and 20, the reference torque distribution can be reduced by 5 times.
Equal torque distribution of 0:50 or unequal torque distribution biased forward or backward is possible. In the present embodiment, reference torque distribution of 36:64 is set in front and back.

Further, the first and second sun gears 17 and 18 and the first and second pinions 19 and 20 are, for example, helical gears, and the first gear train and the second gear train are twisted. At different angles, the thrust load remains without canceling out the thrust load, causing friction torque between the pinion end faces,
Further, the combined force of separation and tangential load due to meshing acts on the surfaces of the first and second pinions 19 and 20 and the shaft portion of the carrier 16 which supports the first and second pinions 19 and 20. The center differential device 4 itself has a differential limiting function by setting so as to generate a friction torque and obtaining a differential limiting torque proportional to the input torque.

Further, between the carrier 16 of the center differential device 4 and the rear drive shaft 5, there is provided a transfer clutch 21 adopting a hydraulic multi-plate clutch for varying the driving force distribution between the front and rear wheels. By controlling the engagement force of the transfer clutch 21, the torque distribution of the front and rear wheels can be variably controlled within the range of the torque distribution ratio by the center differential device 4 from 4WD by the direct connection of 50:50. I have.

The transfer clutch 21 is connected to a transfer clutch drive section 61 constituted by a hydraulic circuit having a plurality of solenoid valves. The transfer clutch 21 is released and connected by the hydraulic pressure generated by the transfer clutch drive section 61. Then, a control signal (an output signal for each solenoid valve) for driving the transfer clutch driving unit 61 is output from a front-rear driving force distribution control unit 60 described later.

On the other hand, the rear final drive 8
It has a differential function between the left and right wheels and a power distribution function, and varies the bevel gear type differential mechanism unit 22, a gear mechanism unit 23 composed of three-row gears, and the distribution of driving force between the left and right wheels at the rear wheels. It is mainly composed of two sets of clutch mechanisms 24 and is housed integrally in a differential carrier 25.

The drive pinion 7 is meshed with a final gear 27 provided on the outer periphery of a differential case 26 of the differential mechanism 22, and transmits a driving force distributed from the center differential device 4 to the rear wheels.

The differential mechanism 22 includes a differential pinion (bevel gear) 29 rotatably supported by a pinion shaft 28 fixed to a differential case 26.
And left and right side gears (bevel gears) 3 that mesh with this
0L and 30R are accommodated in a differential case 26. Ends of rear left and right drive shafts 14rl and 14rr are axially mounted on the side gears 30L and 30R, respectively, in the differential case 26.

That is, the differential mechanism 22 is rotated by the drive pinion 7 so that the differential case 26 is rotated on the same axis as the side gears 30L and 30R, and the differential mechanism 26 is provided between the left and right wheels by a gear mechanism formed inside the differential case 26. It is configured to perform differential operation.

The gear mechanism section 23 is divided into left and right parts with the differential mechanism section 22 interposed therebetween. A first gear 23z1 is fixed to a rear wheel left drive shaft 14rl, and a rear wheel right drive shaft 14rr. A second gear 23z2 and a third gear 23z3 are axially mounted, and these first, second, and third gears 23z1, 2
3z2 and 23z3 are arranged on the same rotation axis.

The first, second and third gears 23z1, 2
3z2 and 23z3 mesh with the fourth, fifth and sixth gears 23z4, 23z5 and 23z6 disposed on the same rotation axis, and the fourth, fifth and sixth gears 23z4, 23z5 and 23z6. A fourth gear 23z4 is axially mounted on the left-wheel-side end of the torque bypass shaft 31 disposed on the rotation shaft core.

At the right wheel end of the torque bypass shaft 31, a clutch mechanism 2 for executing power distribution between the left and right wheels is provided.
4 is provided with a first differential control clutch 24a. The torque bypass shaft 31 is connected to the first differential control clutch 24a via the first differential control clutch 24a.
1 is the clutch hub side, and the shaft side of the sixth gear 23z6 is the clutch drum side), and is freely connectable to the shaft of the sixth gear 23z6 disposed on the left side of the first differential control clutch 24a. .

Further, a second differential control clutch 24b of the clutch mechanism 24 is formed on the torque bypass shaft 31 at a position between the differential mechanism 22 and the fifth gear 23z5. 31 is provided on the right side of the second differential control clutch 24b via the second differential control clutch 24b (the torque bypass shaft 31 is defined as the clutch hub side and the shaft of the fifth gear 23z5 is defined as the clutch drum side). It is freely connectable to the shaft of the fifth gear 23z5.

Then, the first, second, third, fourth, fifth and fifth
Sixth gears 23z1, 23z2, 23z3, 23z4, 23z5,
23z6 each tooth number z1, z2, z3, z4, z
5, z6 are, for example, 82, 78, 86, 46, 50,
42 and the first and fourth gears 23z1, 23
Based on the gear train of z4 ((z4 / z1) = 0.56), the gear train of the second and fifth gears 23z2 and 23z5 ((z5
/Z2)=0.64) is the speed increase, the third and sixth gears 23z
A gear train of 3,23z6 ((z6 / z3) = 0.49) is a reduction gear train.

For this reason, when both the first and second differential control clutches 24a and 24b are not connected and operated, the driving force from the drive pinion 6 passes through the differential mechanism section 22 as it is and the right and left rear wheel drive shafts 14rl and 14rl. 14rr, but the first differential control clutch 24
a, the driving force distributed to the rear wheel right drive shaft 14rr is partially transmitted to the third gear 23z3, the sixth gear 23z6, the first differential control clutch 24a,
The torque is returned to the differential case 26 via the torque bypass shaft 31, the fourth gear 23z4, and the first gear 23z1 in this order. As a result, the torque distribution of the left rear wheel 15rl increases, and if the vehicle is on a normal road surface μ, the vehicle turns right. Recovery is improved.

Conversely, the second differential control clutch 2
4b, a part of the driving force transmitted from the drive pinion 6 to the differential case 26 is transmitted to the first gear 23z1, the fourth gear 23z4, the torque bypass shaft 31, and the second differential control clutch. 24b,
The fifth gear 23z5 and the second gear 23z2 are sequentially passed to the right drive shaft 14rr of the rear wheel to bypass the rear wheel 15rr, so that the torque distribution of the right rear wheel 15rr is increased. Is done.

First and second differential control clutch 2
Reference numerals 4a and 24b are connected to a differential control clutch drive section 66 constituted by a hydraulic circuit having a plurality of solenoid valves, and are released and connected by the hydraulic pressure generated by the differential control clutch drive section 66. Then, a control signal (an output signal to each solenoid valve) for driving the differential control clutch driving section 66 is:
The output is output from a left / right driving force distribution control unit 65 described later.

On the other hand, reference numeral 32 denotes a rear wheel steering section of the vehicle 1, and the rear wheel steering section 32 is driven by a rear wheel steering drive section 71 controlled by a rear wheel steering control section 70 described later. A rear wheel steering motor 33 is provided, and power from the rear wheel steering motor 33 is transmitted via a worm / worm wheel and a link mechanism, and the left rear wheel 15rl,
The right rear wheel 15rr is steered.

Reference numeral 76 denotes a brake drive unit of the vehicle. The brake drive unit 76 is connected to a master cylinder (not shown) connected to a brake pedal operated by a driver. When the brake pedal is operated, the four wheels 15fl, 15fr, 15rl, 15
rr each wheel cylinder (left front wheel cylinder 34
fl, the right front wheel cylinder 34fr, the left rear wheel cylinder 34rl, and the right rear wheel cylinder 34rr), the brake pressure is introduced, whereby the four wheels are braked and braked.

The brake driving unit 76 includes a pressurizing source, a pressure reducing valve,
A hydraulic unit having a pressure intensifying valve and the like. In addition to the brake operation by the driver described above, each wheel cylinder 34fl, 34fr, 34rl, 34rl,
The brake pressure is formed independently for each 34 rr.

The above-described front / rear driving force distribution control unit 60, left / right driving force distribution control unit 65, rear wheel steering control unit 70, and braking force control unit 75 are provided as vehicle behavior control means, respectively. The vehicle 1 includes these control units 6
For 0, 65, 70, and 75, an avoidance traveling control unit 80 that outputs a signal is mounted.

In the figure, an engine control section 91 is a well-known one that performs fuel injection control, ignition timing control, and other general controls for the engine 2. Further, the traction control unit 92 includes wheel speed sensors 41fl, 41f described later.
The slip ratio of each wheel is detected based on each wheel speed from r, 41rl, and 41rr, and when the slip ratio becomes equal to or greater than a preset slip ratio determination value, the brake drive unit 76 or the engine control unit 91 transmits the slip ratio. A predetermined control signal is output to perform automatic braking or torque reduction of the engine 2 to prevent the wheels from spinning.

The own vehicle 1 is provided with various sensors and switches as own vehicle information detecting means for detecting the running state of the own vehicle. That is, each wheel 15fl, 15fr, 15
The wheel speeds of rl and 15rr are wheel speed sensors 41fl and 41f.
r, 41rl, 41rr, are calculated in a predetermined manner and set as the vehicle speed V as the front and rear driving force distribution control unit 60, the left and right driving force distribution control unit 65, the rear wheel steering control unit 70, and the braking force control unit 7.
5 and the avoidance traveling control unit 80. Further, the steering wheel angle θH is detected by the steering wheel angle sensor 42, the yaw rate γ is detected by the yaw rate sensor 43,
Front / rear driving force distribution control unit 60, left / right driving force distribution control unit 6
5, input to the rear wheel steering control unit 70, the braking force control unit 75, and the avoidance traveling control unit 80. Further, the lateral acceleration Gy is detected by the lateral acceleration sensor 44 and is input to the longitudinal driving force distribution control unit 60 and the left and right driving force distribution control unit 65.
Further, the throttle opening θth is
And the gear position is detected by the inhibitor switch 46 and input to the front-rear driving force distribution control unit 60. Further, the engine speed Ne is detected by the engine speed sensor 47 and input to the front / rear driving force distribution control unit 60 and the avoidance traveling control unit 80. Also, the rear wheel steering angle δr
Is detected by the rear wheel steering angle sensor 48 and input to the rear wheel steering control unit 70, and the longitudinal acceleration Gx is
9 and is input to the avoidance traveling control unit 80.
Further, the accelerator opening θac is detected by the accelerator pedal sensor 53 and input to the avoidance traveling control unit 80. Further, ON / OFF of the parking brake is detected by the parking brake switch 54 and input to the avoidance traveling control unit 80. Further, an engine (output) torque Te is input from the engine control unit 91, and a traction control ON-OFF signal is input from the traction control unit 92 to the avoidance traveling control unit 80. Also, in the vehicle 1,
An alarm lamp 55 that is lit by the avoidance traveling control unit 80 during the avoidance traveling is provided on the instrument panel.

The vehicle 1 is provided with a stereo optical system. The stereo optical system includes a set of CCD cameras (for example, a left camera 51L) using a solid-state imaging device such as a charge-coupled device (CCD). , Right camera 51R), and these left and right CCD cameras 51L, 51R are respectively mounted at a certain interval in front of the ceiling in the vehicle cabin so as to stereoscopically image an object outside the vehicle from different viewpoints.

The image signals from the CCD cameras 51L and 51R are input to an obstacle recognizing section 52, and a three-dimensional distance distribution over the entire image is calculated from the parallax of the same object based on the principle of triangulation. And recognizes a road shape and a plurality of three-dimensional objects to detect an obstacle ahead of the traveling road such as a preceding vehicle. That is, in the embodiment of the present invention, the CCD cameras 51L and 51R and the obstacle recognition unit 5
2 constitutes an obstacle recognizing means for recognizing an obstacle ahead of the traveling road and detecting obstacle information.

The obstacle recognition unit 52 includes a CCD camera 51
For each of the two stereo images picked up by the L and 51R, a search is made for a portion where the same object is shown in each minute area, the amount of displacement of the corresponding position is calculated, and the distance to the object is calculated. It stores the distance distribution data (distance image) in such a form, processes the distance distribution data, and recognizes a road shape and a plurality of three-dimensional objects to detect a forward obstacle.

More specifically, in the road detection processing in the obstacle recognition unit 52, only white lines on the actual road are separated and extracted by using three-dimensional position information based on the stored distance image, and the road is stored in the built-in road. By modifying and changing the parameters of the road model that has been adjusted to match the actual road shape, the road shape,
Recognize the driving lane of the vehicle.

In the process of detecting an object that becomes a forward obstacle in the obstacle recognizing unit 52, the distance image is divided into grids at predetermined intervals, and a three-dimensional object that may be an obstacle to travel is provided for each area. Only data is selected and its detection distance is calculated. When the difference in the detection distance to the object in the adjacent area is smaller than the set value, the object is regarded as the same object. On the other hand, when the difference is larger than the set value, the objects are regarded as separate objects and the contour image of the detected object (obstacle) Is extracted. The processing for generating the distance image and detecting the road shape and the object from the distance image is described in Japanese Patent Application Laid-Open No.
The details are described in, for example, Japanese Unexamined Patent Application Publication No. Hei.

The data relating to the front obstacle detected by the obstacle recognition unit 52 (the distance L from the obstacle (preceding vehicle))
s, the speed Vs of the obstacle (preceding vehicle), the deceleration αs of the obstacle (preceding vehicle), etc.) are input to the avoidance traveling control unit 80.

Next, control units for controlling the behavior of the vehicle 1 will be described. The front-rear driving force distribution control unit 60 uses, for example, the method disclosed by the present applicant in Japanese Patent Application Laid-Open No. Hei 8-2274, that is, the equation of motion of the lateral motion of the vehicle using the vehicle speed V, the steering wheel angle θH, and the actual yaw rate γ. Based on the road surface friction coefficient μ based on the ratio of the estimated front and rear wheel cornering power to the equivalent front and rear wheel cornering power on high μ roads, the cornering power of the front and rear wheels is extended to a nonlinear region and estimated. Is estimated. And
A base clutch torque VTDout0 is obtained by referring to a map set in advance in response to the road surface friction coefficient μ.
Input torque Ti (calculated from engine speed Ne and gear ratio i) input to center differential device 3, throttle opening θth and actual yaw rate γ, steering wheel angle θ
Deviation between the target yaw rate γt calculated from H and the vehicle speed V and the actual yaw rate γ (yaw rate deviation Δγ = γ−γt);
The control output torque VT is corrected based on the lateral acceleration Gy, and becomes the basis of the basic clutch engagement force FOtb for the power distribution between the front and rear wheels.
Calculate Dout. Further, the control output torque VTD
out is corrected by the steering wheel angle θ, determined as the basic clutch engagement force FOtb in the transfer clutch 21 as the steering wheel angle sensitive clutch torque, and a predetermined signal corresponding thereto is output to the transfer clutch drive unit 61, The transfer clutch 21 is actuated by hydraulic pressure and applied so as to be a differential limiting force to the center differential device 3 to perform power distribution control between the front and rear wheels.

Here, the correction based on the yaw rate deviation Δγ prevents the base clutch torque VTDout0 from over-steering or under-steering of the vehicle.
The clutch torque is added or reduced in accordance with the deviation between the actual yaw rate γ and the actual yaw rate γ.

For example, when turning, the target yaw rate γt
If the absolute value is large and the actual yaw rate γ (absolute value) is expected to be small and the vehicle is expected to understeer, the clutch torque is corrected to be reduced and the front and rear drive force distribution is adjusted to the rear wheels. It is corrected so as to improve the turning performance by making the weight uneven.

Conversely, when turning, the target yaw rate γ
If t (absolute value) is expected to be small and the actual yaw rate γ (absolute value) is expected to be large, and if the vehicle is expected to tend to oversteer, the clutch torque is corrected to increase and the driving force distribution before and after is increased. Correction is made so as to improve stability by making equal distribution in front and rear.

The longitudinal driving force distribution control unit 60 is supplied with a control signal for improving the turning performance or the stability from the avoidance traveling control unit 80. Then, when the control signal for improving the turning performance is input to the front-rear driving force distribution control unit 60, the calculated target yaw rate γt (absolute value) becomes 1
The target yaw rate γt (absolute value) is corrected to be larger than usual by multiplying by a larger coefficient, the clutch torque is corrected to be reduced, and the front and rear driving force distribution is rear-wheel biased, and the turning performance is corrected to be improved. You. Conversely, when the control signal for improving the stability is input to the front / rear driving force distribution control unit 60, the calculated target yaw rate γt (absolute value) is multiplied by a coefficient smaller than 1, and the target yaw rate γt (absolute value) is normally set. Is corrected so that the clutch torque is increased and the front and rear driving force distributions are in the equal distribution direction, and the stability is improved.

Further, the left / right driving force distribution control unit 65 calculates a clutch torque according to a ground contact load between the left and right of the vehicle based on, for example, the vehicle speed V, the steering wheel angle θH, and the lateral acceleration Gy, and calculates the clutch torque. The first differential control clutch 24a or the second differential control clutch 24a or the second differential control clutch 24a is used to correct the difference between the target yaw rate γt calculated from θH and the vehicle speed V and the actual yaw rate γ to generate the final clutch torque.
The differential control clutch 24b is operated to execute power distribution control between the left and right wheels.

The correction based on the yaw rate deviation Δγ in the left and right driving force distribution control unit 65 also depends on the deviation between the target yaw rate γt and the actual yaw rate γ, which are expected to occur during turning, in order to prevent the vehicle from oversteering or understeering. Thus, the clutch torque is added or reduced.

For example, when turning, the target yaw rate γt
When it is expected that the (absolute value) is large and the actual yaw rate γ (absolute value) is small, and that the vehicle is expected to understeer, it is corrected so that the driving force distribution to the turning outer wheels is increased. Improve turning performance.

On the contrary, when turning, the target yaw rate γ
When t (absolute value) is expected to be small and actual yaw rate γ (absolute value) is expected to be large, and when the vehicle is expected to tend to oversteer, an increase in the driving force distribution to the turning outer wheels is suppressed, Correct to improve stability.

The left / right driving force distribution control unit 65 is supplied with a control signal for improving the turning performance or the stability from the avoidance traveling control unit 80. Then, when a control signal for improving the turning performance is input to the left and right driving force distribution control unit 65, the calculated target yaw rate γt (absolute value) is multiplied by a coefficient larger than 1, and the target yaw rate γt (absolute value) is set higher than usual. Is also greatly corrected, and the driving force distribution of the turning outer wheel is corrected to be large, and the turning performance is improved. Conversely, when a control signal for improving stability is input to the left and right driving force distribution control unit 65, the calculated target yaw rate γt
The target yaw rate γt (absolute value) is corrected to be smaller than usual by multiplying the (absolute value) by a coefficient smaller than 1, and an increase in the driving force distribution to the turning outer wheel is suppressed, thereby improving the stability.

The rear wheel steering control unit 70 controls the vehicle speed V,
Using the steering wheel angle θf and the yaw rate γ, a target rear wheel steering angle δr ′ is calculated based on a predetermined control law in advance, and the required rear wheel steering amount is set by comparing with the current rear wheel steering angle δr. A signal corresponding to the rear wheel steering amount is output to the rear wheel steering drive unit 71 to drive the rear wheel steering motor 33. Then, in accordance with a control signal from the avoidance traveling control unit 80, a correction for setting a large in-phase steering amount of the rear wheel steering angle with respect to the front wheel steering angle and the yaw rate is performed in a predetermined manner.

The control performed by the rear wheel steering control unit 70 will be described in more detail. The control law set in the rear wheel steering control unit 70 is, for example, a known “steering wheel angle reverse phase” in the embodiment of the present invention. + Yaw rate in-phase control law "as a basic control law, and is given by the following equation (1). δr ′ = − kδ0 · f1 · (θH / N) + kγ0 · f2 · γ (1) where kδ0 is a steering angle sensitive gain, kγ0 is a yaw rate sensitive gain, and N is a steering gear ratio.

The yaw rate sensitive gain kγ0 is a coefficient that determines the amount of steering of the rear wheels so as to decrease the yaw rate γ. Further, the steering wheel angle sensitive gain kδ0 is a coefficient that determines the amount of steering of the rear wheels so as to provide steering turning characteristics.

That is, the yaw rate sensitive gain kγ0 is given so as to steer the rear wheels in the same phase as the yaw rate γ. As the yaw rate sensitive gain kγ0 increases, the vehicle tends to travel diagonally without turning and the yaw rate sensitive gain kγ0 increases. Generation of γ can be prevented. In other words, the vehicle characteristics have reduced turning characteristics and improved stability. As described above, the yaw rate sensitive gain kγ0 can be regarded as a coefficient indicating how much the steering amount should be given to the rear wheel with respect to the generated yaw rate γ to prevent the generation of the yaw rate γ.

However, the yaw rate sensitive gain kγ
If it is only 0, the vehicle cannot turn. To prevent this, a steering wheel angle sensitive gain kδ0 is set. That is, the turning characteristics of the vehicle are improved by steering the rear wheels in the opposite phase with respect to the steering wheel angle θH. Handle angle sensitive gain kδ for handle angle θH
The vehicle turns by setting the term of 0 to be larger. However, when the steering is returned to the neutral state, the control law includes only the term of the yaw rate sensitive gain kγ0, so that after turning, the rear wheels are steered in the direction of eliminating the yaw rate γ (the direction of eliminating the vehicle wobble). .

The steering angle sensitive gain kδ0 is calculated based on the cornering power of the front wheels and the rear wheels.
Does not change. However, in a state where the vehicle speed is close to 0, the steering wheel angle sensitive gain k
δ0 is set to a small value.

With respect to the steering wheel angle sensitive gain kδ0 and the yaw rate sensitive gain kγ0 set as described above,
In the embodiment of the present invention, the yaw rate responsive gain kδ0 can be corrected by multiplying by the rear wheel steering angle correction value f1 by inputting a control signal from the avoidance traveling control unit 80. The gain kγ0 can be corrected by multiplying the rear wheel steering angle correction value f2.

That is, in order to improve the turning performance, the steering wheel angle sensitive gain kδ0 is corrected by multiplying the rear wheel steering angle correction value f1 larger than 1 so that its absolute value becomes larger. In contrast, the rear wheels are steered in the opposite phase to the normal.

On the contrary, the steering wheel angle sensitive gain kδ
In order to improve the stability at 0, the absolute value is corrected to be smaller by multiplying the rear wheel steering angle correction value f1 smaller than 1 so that the rear wheel is in the opposite phase to the steering wheel angle θH. The correction is made so that the steering is reduced and the turning performance of the vehicle is prevented from being improved.

The yaw rate responsive gain kγ0 is corrected to be smaller than usual by multiplying the rear wheel steering angle correction value f2 smaller than 1 in order to improve the turning performance. The wheels are corrected small in phase.

On the contrary, the yaw rate sensitive gain kγ
To improve the stability at 0, the rear wheel is corrected to be larger than usual by multiplying it by a rear wheel steering angle correction value f2 larger than 1, and the rear wheels are increased in phase with respect to the yaw rate γ so that the turning of the vehicle is started. Is corrected so as to suppress the improvement of the performance.

It is needless to say that an effect can be obtained even if only one of the correction of the steering wheel angle sensitive gain kδ0 and the correction of the yaw rate sensitive gain kγ0 is performed depending on the vehicle.

The braking force control unit 75 determines a wheel to be braked based on the target yaw rate γt obtained from the vehicle speed V and the steering wheel angle θH and the actual yaw rate γ, and applies a calculated braking force to the vehicle, thereby providing an optimum braking force for the vehicle. Basically, a yaw moment is generated. Specifically, the target yaw rate γt
When the (absolute value) is large and the actual yaw rate γ (absolute value) is small and the vehicle tends to understeer, braking of the rear inner wheel in the turning direction is executed to improve the turning performance of the vehicle. Conversely, the target yaw rate γt (absolute value) is small,
When the actual yaw rate γ (absolute value) is large and the vehicle tends to oversteer, braking of the outer front wheel in the turning direction is executed to improve the stability of the vehicle.

The braking force control unit 75 is supplied with a control signal for improving the turning performance or the stability from the avoidance traveling control unit 80. When the control signal for improving the turning performance is input to the braking force control unit 75, the calculated target yaw rate γt (absolute value) is multiplied by a coefficient larger than 1, and the target yaw rate γt (absolute value) becomes larger than usual. Will be corrected. Conversely, when a control signal for improving stability is input to the braking force control unit 75, the calculated target yaw rate γt (absolute value) is multiplied by a coefficient smaller than 1, so that the target yaw rate γt (absolute value) is higher than normal. It is corrected small.

Next, the avoidance traveling control section 80 will be described. The avoidance traveling control unit 80 includes the vehicle speed V and the steering wheel angle θ.
H, yaw rate γ, longitudinal acceleration Gx, accelerator opening θa
c, engine speed Ne, parking brake ON-
Each traveling and operation information of the own vehicle 1 such as the OFF state, the engine torque Te, the traction control ON-OFF state, and the like are input, and the obstacle (preceding vehicle) information (the obstacle (preceding vehicle) ), The speed Vs of the obstacle (preceding vehicle), the deceleration αs of the obstacle (preceding vehicle), etc.)
Is entered. Then, based on the obstacle information, the own vehicle information, and the road surface information estimated by the calculation, it is determined whether or not the own vehicle 1 can avoid the obstacle only by the braking operation of the own vehicle 1. When it is not possible to avoid the obstacle, and when the avoidance operation for the obstacle of the own vehicle 1 is not performed, the mode shifts to the avoidance traveling mode according to the steering wheel operation and the vehicle behavior, and the control unit 60, 65, 70 of each vehicle behavior. , 75
In this case, a signal for changing the control characteristic to improve the turning characteristic of the control characteristic or to improve the stability is output. Further, during the avoidance traveling mode, a signal for changing the control characteristics in the avoidance traveling mode is variably controlled according to the steering operation and the vehicle behavior.

As shown in FIG. 2, the avoidance traveling control unit 80 includes a road surface friction coefficient estimating unit 81, a road surface gradient estimating unit 82, a required deceleration distance calculation unit 83, a required deceleration distance correction unit 84, a target yaw rate calculation unit 85, It mainly comprises a yaw rate deviation calculating section 86, an avoidance operation determining section 87, a control change setting section 88, and an alarm driving section 89.

The road friction coefficient estimating unit 81 receives the vehicle speed V, the steering wheel angle θH, and the actual yaw rate γ, and extends the cornering power of the front and rear wheels to a non-linear region based on the equation of motion of the lateral motion of the vehicle as described above. The road surface friction coefficient μ is estimated according to the road surface condition based on the ratio of the estimated cornering power of the front and rear wheels to the equivalent cornering power of the front and rear wheels on a high μ road. Then, the estimated road surface friction coefficient μ is output to the required deceleration distance calculation unit 83.

The road gradient estimating section 82 receives the vehicle speed V and the longitudinal acceleration Gx, and changes the vehicle speed V at every set time (m / m).
s ² ), the road surface gradient SL (%) is calculated by the following equation (2) using the vehicle speed change rate (m / s ² ) and the longitudinal acceleration Gx, and is output to the required deceleration distance calculation unit 83. . Assuming that the gravitational acceleration is g (m / s ² ) and the ascending direction of the road surface gradient is (+), the road surface gradient SL = (longitudinal acceleration Gx−vehicle speed change rate / g) · 100 (2)

Incidentally, as shown in the following equation (3), the engine output torque (N-m), the torque ratio of the torque converter (for an automatic transmission vehicle), the transmission gear ratio, the final gear ratio, and the tire radius (m ), Running resistance (N), vehicle mass (kg), vehicle speed change rate (m / s ² ), and gravitational acceleration as g (m / s ² ).
L may be calculated. Road surface gradient SL = tan (sin ^-1 ((((engine output torque / torque ratio of torque converter / transmission gear ratio / final gear ratio / tire radius) -running resistance) / running resistance) / vehicle mass-vehicle speed change rate) / g) ) · 100) ≒ ((((engine output torque / torque ratio of torque converter / transmission gear ratio / final gear ratio / tire radius) −running resistance) / vehicle mass−vehicle speed change rate) / g)) · 100 (3)

As described above, in the avoidance traveling control unit 80, the road surface friction coefficient μ is estimated by the road surface friction coefficient estimation unit 81, and the road surface gradient SL is estimated by the road surface gradient estimation unit 82. The unit 81 and the road surface gradient estimating unit 82 are provided as road surface information estimating means for estimating the road surface information on which the vehicle is traveling.

The required deceleration distance calculation unit 83 calculates the vehicle speed V, the obstacle (preceding vehicle) speed Vs, and the obstacle (preceding vehicle) deceleration αs
(M / s ² ) is input, and the road surface friction coefficient estimating unit 8 is input.
1, the road surface friction coefficient μ and the road surface gradient SL from the road surface gradient estimating unit 82 are input, and only the braking of the vehicle 1 is performed in consideration of the relative motion between the vehicle 1 and an obstacle (preceding vehicle). The minimum distance (required deceleration distance) LGB at which an obstacle (preceding vehicle) can be avoided is calculated. Required deceleration distance L
GB is calculated by the following equation (4) and output to the necessary deceleration distance correction unit 84. Necessary deceleration distance LGB = (1/2) · (V−Vs) ² / ((μ− (SL / 100)) · g−αs) (4)

The required deceleration distance correction unit 84 receives the vehicle speed V, the obstacle (preceding vehicle) speed Vs, and the obstacle (preceding vehicle) deceleration αs, and further, based on the vehicle speed V, calculates the deceleration α (m / m / s
² ) is calculated, and the required deceleration distance LGB is corrected in consideration of the delay of the braking operation by the driver, as shown in the following equation (5). Assuming that the driver's operation delay time set in advance is Ttd (s), the required deceleration distance LGB = LGB + (V−Vs) · Ttd + (１ ／) · (αs−α) · Ttd ² (5) The required deceleration distance LGB corrected by the required deceleration distance correction unit 84 is output to the control change setting unit 88.

The target yaw rate calculation section 85 receives the vehicle speed V and the steering wheel angle θH, and calculates a target yaw rate γt. The calculation of the target yaw rate γt is substantially the same as that executed by the other vehicle behavior control units (for example, the front / rear driving force distribution control unit 60, the left / right driving force distribution control unit 65, and the braking force control unit 75). 6) is calculated by the equation. Target yaw rate γt = 1 / (1 + TS · γt0) (6) where S is a Laplace operator, T is a first-order lag time constant, γ
t0 is the target yaw rate steady-state value, and the first-order lag time constant T
Is given by the following equation (7). Primary delay time constant T = (m · Lf · V) / (2 · L · Kr) (7) where m is the vehicle mass, L is the wheel base, Lf is the distance between the front shaft and the center of gravity, and Kr is Rear equivalent cornering power.

The target steady-state yaw rate value γt0 is given by the following equation (8). Target yaw rate steady value γt0 = Gγδ · (θH / n) (8) where n is the steering gear ratio and Gγδ is the yaw rate gain. Here, the yaw rate gain Gγδ is obtained by the following equation (9). Yaw rate gain Gγδ = 1 / (1 + A · V ² ) · (V / L) (9) A is a stability factor determined by the specifications of the vehicle,
It is calculated by the following equation (10). Stability factor A = − (m / (2 · L ² )) · (Lf · Kf−Lr · Kr) / (Kf · Kr) (10) In equation (10), Lr is the distance between the rear axis and the center of gravity. The distance, Kf, is the front equivalent cornering power.

The yaw rate deviation calculating section 86 receives the actual yaw rate γ from the yaw rate sensor 43 and the target yaw rate γt from the target yaw rate calculating section 85, calculates the yaw rate deviation Δγ by equation (11), and sets the control change setting section. 88. Yaw rate deviation Δγ = γ−γt (11)

The avoidance operation determining unit 87 determines whether the steering wheel angle θH
Longitudinal acceleration Gx, engine speed Ne, accelerator opening θ
ac, engine torque Te, parking switch ON-
An OFF state and an ON-OFF state of traction control are input. When any of the longitudinal acceleration Gx, the engine speed Ne, the accelerator opening θac, and the engine torque Te is equal to or greater than a threshold value set in advance for each value, or when the traction control is in an ON state, It is determined that an acceleration operation by the driver (that is, an obstacle avoidance operation by acceleration) is being performed. When the steering wheel angle θH is equal to or larger than a preset threshold value or when the parking switch is in the ON state, it is determined that the turning operation by the driver (that is, the obstacle avoiding operation by turning) is being performed. That is, the avoidance operation determination unit 8
Reference numeral 7 is provided as avoidance operation determination means.

The engine speed Ne and the accelerator opening θ
ac, engine torque Te, steering wheel angle θH
If the amount of each change is equal to or greater than a preset threshold, it may be determined that the driver has performed an avoidance operation.

The control change setting section 88 calculates the steering wheel angle θH,
The actual yaw rate γ and the distance Ls from the obstacle (preceding vehicle) are input, the required deceleration distance LGB from the required deceleration distance corrector 84, the target yaw rate γt from the target yaw rate calculator 85, and the yaw rate deviation from the yaw rate deviation calculator 86. Δ
γ, the determination result of the presence / absence of the avoidance operation by the driver is input from the avoidance operation determination unit 87, and when the own vehicle 1 cannot avoid the obstacle only by the braking operation, the avoidance operation for the obstacle of the own vehicle 1 is performed. When there is no steering operation and the vehicle behavior, the vehicle shifts to the avoidance traveling mode. When the vehicle shifts to the avoidance traveling mode, each of the vehicle behavior control units 60, 65, 7
Signals to be output to 0 and 75 (signals for improving turning performance, signals for improving stability, or signals for canceling avoidance driving mode)
Is set and output. When the mode is shifted to the avoidance traveling mode, a signal is output to the alarm drive unit 89, and the alarm lamp 55 is lit until the avoidance traveling mode is canceled.

That is, the required deceleration distance calculation unit 83, the required deceleration distance correction unit 84, and the control change setting unit 88 form braking avoidance determination means. The control change setting unit 88 also has a function as an avoidance control means. ing.

Next, the control of the own vehicle 1 in the avoidance travel control by the avoidance travel control section 80 will be described with reference to the flowcharts of the avoidance travel control programs shown in FIGS. This avoidance traveling control program is executed at predetermined time intervals. First, in step (hereinafter abbreviated as “S”) 101, the host vehicle information is read, and S1 is executed.
Proceeding to 02, the target yaw rate γt is calculated by the equation (6).

When the process proceeds to S103, it is determined whether or not the vehicle is in the avoidance traveling mode. If the vehicle is not in the avoidance traveling mode, the process proceeds to S104. If the vehicle is in the avoidance traveling mode, the process proceeds to S124.

Here, first, instead of the avoidance traveling mode, S
The case of proceeding to step 104 will be described. When proceeding to S104, the obstacle information is read, and when proceeding to S105, it is determined whether or not an obstacle (including a preceding vehicle) exists.

If it is determined in S105 that no obstacle exists, the program exits the program. On the other hand, if there is an obstacle, the process proceeds from S105 to S106 to estimate the road surface friction coefficient μ, and proceeds to S107 to estimate the road surface gradient SL by the above equation (2).

Thereafter, the flow advances to S108 to calculate the required deceleration distance LGB by the above equation (4), and the flow advances to S109 to correct the required deceleration distance LGB by the above equation (5).

At S110, the required deceleration distance LGB finally corrected and calculated is compared with the distance Ls to the obstacle, and as a result of this comparison, the distance Ls to the obstacle is required. Larger than the deceleration distance LGB (Ls> L
GB), if it can be determined that the collision with the obstacle can be avoided only by braking the own vehicle 1, the program exits the program as it is.

On the other hand, in the determination in S110, the distance Ls to the obstacle is less than the required deceleration distance LGB (Ls ≦ LGB),
If it is determined that the collision with the obstacle cannot be avoided only by braking the own vehicle 1, the process proceeds to S111.

The steps S111 to S117 are steps for determining whether or not the driver is performing an avoidance operation.
At 111, the accelerator opening θac is equal to or greater than a set value, at S112, the engine speed Ne is equal to or greater than the set value, at S113, the engine torque Te is equal to or greater than the set value, or at S114, the longitudinal acceleration G
It is determined whether x is equal to or greater than the set value and whether traction control is operating (ON) in S115. Then, if any of these procedures applies (in the case of YES),
It is determined that the avoidance operation by acceleration by the driver is being executed, the program exits, and the operation and intention of the driver are prevented from being hindered.

On the other hand, if none of the determinations in S111 to S115 is true, that is, if it is determined that the driver has not performed the avoidance operation due to acceleration, the process proceeds to S116, where the steering wheel angle θH is equal to or larger than the set value. If it is determined that the steering wheel angle θH is smaller than the set value, the process proceeds to S117, where it is determined whether the parking brake is ON.

If either of S116 and S117 is applicable (in the case of YES), it is determined that the driver has performed the avoidance operation by the turning operation, the program exits, and the operation and intention of the driver are prevented from being hindered. I do.

Conversely, when neither of S116 and S117 is satisfied, that is, when it is determined that the driver has not executed the avoidance operation by the turning operation (S111 to S1)
If it is determined that the driver has not generally performed the avoidance operation together with the determination result of No. 15), the process proceeds to S118,
After taking note of the front wheel steering direction in the driving state, S
Go to 119.

Then, in S119, it is determined whether or not the absolute value of the steering wheel angle θH is larger than a predetermined value, that is, whether or not the steering operation is already performed. If the steering wheel operation is large, the process proceeds to S120.

In S120, the absolute value of the target yaw rate γt is compared with the absolute value of the actual yaw rate γ to determine the state of the vehicle behavior, and the absolute value of the target yaw rate γt is larger than the absolute value of the actual yaw rate γ (| γt |> | γ |),
When it can be considered that the behavior of the vehicle has an understeer tendency, the process proceeds to S121, and each of the vehicle behavior control units 60, 65, 7
A signal is output to 0, 75 so as to change the control characteristic in a direction in which the turning property is improved.

Specifically, the target yaw rate γt (absolute value) calculated by the front / rear driving force distribution control unit 60 is multiplied by a coefficient larger than 1 for the front / rear driving force distribution control unit 60, and the target yaw rate γt (Absolute value) is corrected to be larger than usual, the clutch torque is corrected to be reduced, and the front and rear driving force distribution is rear-wheel biased, so that the turning performance is improved.

For the left and right driving force distribution control unit 65, the target yaw rate γt (absolute value) calculated by the left and right driving force distribution control unit 65 is multiplied by a coefficient larger than 1 to obtain the target yaw rate γt (absolute value). ) Is corrected to be larger than usual, and the driving force distribution of the turning outer wheels is corrected to be larger, so that the turning performance is improved.

Further, for the rear wheel steering control unit 70,
By multiplying the steering wheel sensitivity gain kδ0 by a rear wheel steering angle correction value f1 larger than 1, the absolute value is corrected to be larger, and the rear wheels are steered in a reverse phase with respect to the steering wheel angle θH. To improve the turning performance. The yaw rate sensitive gain kγ0 is 1
By multiplying by a smaller rear wheel steering angle correction value f2, the correction is made to be smaller than usual, and the rear wheels are corrected to be smaller in phase with respect to the yaw rate γ to improve the turning performance.

For the braking force control unit 75, the target yaw rate γt (absolute value) calculated by the braking force control unit 75 is multiplied by a coefficient greater than 1, so that the target yaw rate γt (absolute value) is higher than usual. Is also greatly corrected to improve the turning performance.

On the other hand, as a result of the comparison between the absolute value of the target yaw rate γt and the absolute value of the actual yaw rate γ in S120, the absolute value of the target yaw rate γt is smaller than the absolute value of the actual yaw rate γ (| γt | ≦ | γ |). If it can be considered that the behavior of the vehicle is in an oversteer tendency, the process proceeds to S122, and a signal is output to each of the vehicle behavior control units 60, 65, 70, 75 so as to change the braking characteristic in a direction in which the stability is improved. I do.

Specifically, the target yaw rate γt (absolute value) calculated by the longitudinal drive force distribution control unit 60 is multiplied by a coefficient smaller than 1 to the longitudinal drive force distribution control unit 60, and the target yaw rate γt The (absolute value) is corrected to be smaller than usual, the clutch torque is corrected to be increased, and the front and rear driving force distributions are in the same distribution direction, so that the stability is improved.

For the left and right driving force distribution control unit 65, the target yaw rate γt (absolute value) calculated by the left and right driving force distribution control unit 65 is multiplied by a coefficient smaller than 1 to obtain the target yaw rate γt (absolute value). ) Is corrected to be smaller than usual, and an increase in the driving force distribution to the turning outer wheel is suppressed, so that the stability is improved.

Further, for the rear wheel steering control unit 70,
By multiplying the steering wheel angle sensitive gain kδ0 by a rear wheel steering angle correction value f1 smaller than 1, the absolute value is corrected so as to be smaller, and the rear wheel is steered in the opposite phase with respect to the steering wheel angle θH. And improve stability. The yaw rate sensitive gain kγ0 is 1
By multiplying by the larger rear wheel steering angle correction value f2, the correction is made to be larger than usual, and the rear wheel is corrected to be larger in the same phase direction with respect to the yaw rate γ to improve the stability.

For the braking force control unit 75, the target yaw rate γt (absolute value) calculated by the braking force control unit 75 is multiplied by a coefficient smaller than 1, so that the target yaw rate γt (absolute value) is higher than usual. Is also corrected to be small, and the stability is improved.

If the absolute value of the steering wheel angle θH is equal to or smaller than the predetermined value in S119, it is expected that the steering wheel operation will be performed in order to avoid an obstacle in the future and the vehicle will be turned. Vehicle behavior control units 60, 65, 7
A signal is output to 0, 75 so as to change the control characteristic in a direction in which the turning property is improved.

Thus, after the processing of S121 or S122, the process proceeds to S123, in which a signal is output to the alarm drive unit 89 to notify the driver of the avoidance driving mode, the alarm lamp 55 is turned on, and the program exits. .

Next, the case where it is determined in S103 that the vehicle is in the avoidance driving mode and the process proceeds to S124 will be described. S10
When the process proceeds from S3 to S124, it is determined whether or not the current avoidance driving mode causes each of the vehicle behavior control units 60, 65, 70, 75 to change the control characteristics in a direction in which the turning performance is improved.

If it is determined in step S124 that the turning direction is being changed, the process proceeds to step S125 in which the front wheel steering direction is reversed, that is, whether the current front wheel steering direction is reversed with respect to the front wheel steering direction stored in step S118. The determination is made, and if not inverted, the program is exited as it is, and if inverted, the process proceeds to S126 to change the control characteristics for each of the vehicle behavior control units 60, 65, 70, 75 that are changing in the direction of improving turning characteristics. A signal is output so as to change the output in a direction to improve stability.

On the other hand, if it is determined in step S124 that the stability is being changed, the process proceeds to step S127. In S127, it is determined whether or not the state in which the absolute value of the steering wheel angle θH is equal to or less than the predetermined value has continued for a predetermined time or more.
8, the yaw rate deviation Δγ is calculated by the above equation (11), and the process proceeds to S129, where it is determined whether or not the state in which the absolute value of the yaw rate deviation Δγ is equal to or less than a predetermined value has continued for a predetermined time or more. Exits the program as it is.

When either one of S127 and S129 satisfies the condition, that is, the state where the absolute value of the steering wheel angle θH is equal to or smaller than a predetermined value continues for a predetermined time or the state where the absolute value of the yaw rate deviation Δγ is equal to or smaller than a predetermined value. If the control has continued for a predetermined time or more, the process proceeds to S130, in which the instruction to change the control characteristics to each of the vehicle behavior control units 60, 65, 70, and 75 is released (the avoidance traveling mode is released), and S131 is performed.
To release the signal output to the alarm drive unit 89 and exit the program.

As described above, in the embodiment of the present invention, an obstacle to the host vehicle 1 is determined in advance, and the road surface friction coefficient, the road surface information of the road surface gradient, and the relative motion between the host vehicle 1 and the obstacle are taken into consideration. Thus, it is accurately determined whether or not the own vehicle 1 can avoid an obstacle only by the braking operation. When the host vehicle 1 cannot avoid the obstacle by only the braking operation of the host vehicle 1 and when the host vehicle 1 is not performing the avoiding operation on the obstacle, the steering operation and the understeer or the oversteer at that time are performed. Since the vehicle behavior control units 60, 65, 70, and 75 are shifted to the avoidance traveling mode and actuated according to the vehicle behavior in the state, the driver can safely and easily perform the avoidance driving of the obstacle. In addition, when the driver is performing the avoidance operation, the avoidance control is not performed, so that the operation and intention of the driver are not hindered,
It is possible to reliably prevent a sense of incongruity. In addition, in avoidance driving, in general, the turning performance is emphasized in the first half, and stability is emphasized in the second half after the steering wheel is turned over after passing through an obstacle. This is accurately determined from the change, and the necessary control is executed by each of the vehicle behavior control units 60, 65, 70, and 75. In addition, the release of the avoidance traveling mode also detects the end of the avoidance traveling due to the driver's steering operation, or
It detects the stability of the behavior of the vehicle after avoiding the obstacle and executes it at an accurate timing.

In the embodiment of the present invention, an example has been shown in which an image captured by the pair of CCD cameras 51R and 51L is processed to detect a forward obstacle, but the present invention is not limited to this. The obstacle may be detected using a device such as an ultrasonic radar or a laser.

In the embodiment of the present invention, the vehicle 1
Is a front / rear driving force distribution control unit 6 as a vehicle behavior control unit.
0, a left and right driving force distribution control unit 65, a rear wheel steering control unit 70, and a braking force control unit 75.
From the vehicle behavior control units 60, 65, 70, and 75, the present invention is applicable as long as at least one of these vehicle behavior control units is controlled by the avoidance traveling control unit 80. It goes without saying that you can do it.

In the embodiment of the present invention, the driver's avoidance operation is determined by specifically using seven parameters. However, it is determined by one or more of these parameters. May be. Further, if the avoidance operation of the driver can be determined, it is needless to say that the determination can be performed using known parameters other than these parameters. In addition, the determination order of each parameter is not limited to the present embodiment.

Further, in the embodiment of the present invention, the vehicle behavior control units 60, 65, 70, and 75 perform an increase correction of an absolute value of a parameter (a target yaw rate or a steering wheel sensitivity gain, a yaw rate sensitivity gain) by: The correction is performed by multiplying by a constant larger than 1, and the decrease correction is performed by multiplying by a constant smaller than 1. However, the correction is not limited to this.

Further, in the embodiment of the present invention, the front / rear driving force distribution control unit 60 uses the target yaw rate as a correction parameter during the control, but is not limited to this control method. In this case, it is sufficient if the engagement torque of the transfer clutch 21 can be set so that the driving force distribution is rearwardly biased to improve the turning performance, and the driving force distribution is equally distributed to the front and rear to improve the stability. .

Further, in the embodiment of the present invention, the target yaw rate is used as a correction parameter during control in the left and right driving force distribution control unit 65, but the present invention is not limited to this control method. In this case, when improving the turning performance, when the vehicle is determined to have an understeer tendency that is stronger than the reference steer characteristic, the direction in which the outer wheel drives the target left / right driving force distribution ratio more strongly, or the inner wheel becomes stronger. Correct in the direction of strong braking. Also, in order to improve the stability, when the vehicle is determined to have an understeer tendency or an oversteer tendency that is weaker than the reference steer characteristic, the direction in which the inner wheel drives the target left / right driving force distribution ratio more strongly. Alternatively, the correction is made in the direction in which the outer wheel brakes more strongly.

Further, in the embodiment of the present invention, the control law in the rear wheel steering control unit 70 has been described as an example in which the basic control law is “steering angle reversed phase + yaw rate in-phase control law”. However, for example, a well-known “control law of a yaw rate feedback method” or a “control law of a front wheel steering angle proportional method” may be used. Then, even with other control rules, in order to improve the turning performance, the turning angle of the rear wheel with respect to the front wheel is corrected in the opposite phase, including reducing the amount of steering in the same phase. Also, to improve stability,
The steering angle of the rear wheel with respect to the front wheel is corrected in the same phase direction, including reducing the amount of reverse phase steering.

Further, the braking force control by the braking force control section 75 is not limited to the embodiment of the present invention. In order to improve the turning performance, when it is determined that the vehicle has an understeer tendency that is stronger than the reference steering characteristic, the target yaw moment is increased and the applied braking force is increased and corrected. In order to improve the stability, when the vehicle is judged to have an understeer tendency or an oversteer tendency that is weaker than the reference steer characteristic, the target yaw moment is increased and the braking force to be added is increased and corrected. You may do it.

[0131]

As described above, according to the present invention,
The obstacles to the vehicle are determined in advance, and the control device of each vehicle behavior naturally operates properly without hindering the driver's operation and intention over the entire avoidance traveling in consideration of various traveling information. It is possible to appropriately perform avoidance traveling.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an entire vehicle motion control device in a vehicle.

FIG. 2 is a functional block diagram illustrating an avoidance traveling control unit.

FIG. 3 is a flowchart of an avoidance traveling control program.

FIG. 4 is a flowchart continued from FIG. 3;

FIG. 5 is a flowchart continued from FIG. 4;

FIG. 6 is a flowchart continued from FIG. 3;

[Explanation of symbols]

Reference Signs List 1 own vehicle 42 handle angle sensor (own vehicle information detecting means) 43 yaw rate sensor (own vehicle information detecting means) 49 longitudinal acceleration sensor (own vehicle information detecting means) 51R, 51L CCD camera (obstacle recognizing means) 52 obstacle recognition Unit (obstacle recognition means) 60 front / rear driving force distribution control unit (vehicle behavior control means) 65 left / right driving force distribution control unit (vehicle behavior control means) 70 rear wheel steering control unit (vehicle behavior control means) 75 braking force control unit (Vehicle behavior control means) 80 Avoidance traveling control unit (road surface information estimation means, avoidance operation determination means, braking avoidance determination means, avoidance control means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60T 8/58 ZYW B60T 8/58 ZYWE B62D 6/00 ZYW B62D 6/00 ZYW 7/14 7/14 A // B62D 101: 00 101: 00 103: 00 103: 00 111: 00 111: 00 113: 00 113: 00 137: 00 137: 00 F term (reference) 3D032 CC12 DA03 DA24 DA25 DA29 DA33 DA49 DA76 DA82 DA88 DA93 EA06 FF01 FF08 GG01 3D034 CA01 CC01 CC09 CD04 CD06 CD07 CD12 CE05 3D041 AA71 AB01 AC00 AC26 AD00 AD02 AD04 AD10 AD22 AD23 AD31 AD42 AD47 AD50 AD51 AE00 AE41 AF01 3D046 BB18 BB21 BB29 GG02 H17H06 H05H01H01H01H05 MM34

Claims (8)

[Claims] 1. An obstacle recognizing means for recognizing an obstacle ahead of a traveling road to detect obstacle information, an own vehicle information detecting means for detecting a traveling state of an own vehicle, and a road surface for estimating traveling road surface information. Information estimating means, vehicle behavior control means for controlling the vehicle behavior by varying the turning performance of the own vehicle, avoidance operation determining means for determining the state of the avoidance operation of the own vehicle with respect to the obstacle, and the obstacle Braking avoidance determination means for determining whether or not the own vehicle can avoid the obstacle based on only the braking operation of the own vehicle based on the information, the own vehicle information, and the road surface information; and When the obstacle cannot be avoided, and the vehicle behavior control means is shifted to the avoidance traveling mode according to the steering wheel operation and the vehicle behavior when the avoidance operation on the obstacle of the own vehicle is not performed, A vehicle motion control device comprising: an avoidance control unit that varies control by the vehicle behavior control unit in the avoidance travel mode in accordance with a steering wheel operation and a vehicle behavior during the avoidance travel mode. 2. The avoidance operation determining means determines that the avoidance operation is being performed when at least one of the acceleration operation and the turning operation of the own vehicle is performed. The vehicle motion control device according to any one of the preceding claims. 3. The acceleration operation of the host vehicle is performed by a traction control unit that controls an accelerator opening, an engine speed, an engine torque, a longitudinal acceleration, and a driving force transmitted to a road surface in accordance with a wheel slip. The vehicle motion control device according to claim 2, wherein the detection is performed by at least one of the operations. 4. The vehicle motion control device according to claim 2, wherein the turning operation of the own vehicle is detected by at least one of a steering wheel operation and a parking brake operation. 5. The avoidance traveling mode by the avoidance control means includes a first mode in which the control of the vehicle behavior control means is changed in a direction in which turning performance is improved more than usual, and
The vehicle motion control device according to any one of claims 1 to 4, further comprising a second mode in which control is changed in a direction in which the vehicle attitude is maintained more strongly than in the first mode. 6. The avoidance travel mode by the avoidance control means is such that when the steering direction of the steering wheel is reversed when the vehicle behavior control means is in the first mode, the vehicle behavior control means is in the second mode. 6. The vehicle motion control device according to claim 5, wherein the switching is performed. 7. The avoidance traveling mode by the avoidance control means includes a case where a state where steering is small is continued for a predetermined time or more, and a case where a deviation between a target yaw rate and an actual yaw rate is within a predetermined set range. The vehicle motion control device according to any one of claims 1 to 6, wherein the avoidance traveling mode is canceled in at least one of cases where the vehicle continues for a predetermined time or more. 8. The vehicle behavior control means includes: a braking force control unit that controls a braking force to be applied to predetermined selected wheels based on a running state of the vehicle; A rear wheel steering controller for steering control, a front / rear driving force distribution controller for variably controlling the driving force distribution between the front and rear wheels according to the traveling state of the vehicle, and a driving force distribution between left and right wheels according to the traveling state of the vehicle The vehicle motion control device according to any one of claims 1 to 7, wherein the vehicle motion control device is at least one of a left and right driving force distribution control unit that variably controls a vehicle.