JP2008184123A - Yawing moment control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately perform behavior correction during vehicle traveling and enhance stability during vehicle traveling when performing yawing moment control of a vehicle having three or more axles. <P>SOLUTION: By adjusting brake force applied to tires in intermediate axles excluding the foremost and rearmost axles of the vehicle 100 having the three or more axles, a yawing moment of the vehicle 100 is controlled. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an apparatus for controlling a yaw moment of a vehicle provided with three or more axles.

In the field of ordinary automobiles such as passenger cars, the running stability of the vehicle is controlled by controlling the yaw (yawing) direction of the vehicle body, that is, the moment (moment force) that rotates around the center of gravity when the vehicle body is viewed from above. Various inventions have been proposed to improve the steering performance and the maneuverability, and are known from various patent documents to be described later.

  The outline of the invention disclosed in each patent document will be described with reference to FIGS.

  FIG. 18 is a view of the vehicle 1100 as seen from above.

The vehicle 1100 is a two-shaft, four-wheel vehicle including a front axle 1111 and a rear axle 1112 of the vehicle body 1101. The front axle 1111 is a steered shaft, and the direction of the front wheels 1121 and 1122 with respect to the vehicle body 1101, that is, the turning angle δ changes according to the steering.

Note that the turning angle δ corresponds to the steering angle γ of the steering. The rear axle 1112 is a non-steering shaft, and the orientation of the rear wheels 1123 and 1124 with respect to the vehicle body 1101 is fixed.

In FIG. 18, the vertical axis in the vertical direction passing through the center of gravity G of the vehicle is defined as the Z axis, the angle around the Z axis is defined as the yaw angle α, and the angular velocity around the Z axis is defined as the yaw rate r. In addition, an angle formed by the posture direction of the vehicle 1100 and the traveling direction of the vehicle 1100 is defined as a slip angle (side slip angle) β.

FIG. 19A shows the vehicle body 11 when the rear tires 1123 and 1124 are braked.
FIG. 6 is a diagram for explaining yaw moments ΔML and ΔMR acting on 01;

That is, when a braking force (braking force) FL acts on the tire 1123 for the left rear wheel,
ΔML = dL × FL
Works. DL is the distance from the vehicle center of gravity G to the direction line of the braking force FL.

Further, when the braking force FR acts on the tire 1124 on the right rear wheel,
ΔMR = dR × FR
Works. Note that dR is the length of the arm of the yaw moment, that is, the distance from the vehicle center of gravity G to the direction line of the braking force FR.

FIG. 19B shows the vehicle body 11 when the front tires 1121 and 1122 are braked.
FIG. 6 is a diagram for explaining yaw moments ΔML ′ and ΔMR ′ acting on 01;

That is, when the braking force FL ′ acts on the tire 1121 of the left front wheel, the yaw moment
ΔML ′ = dL ′ × FL ′
Works. DL ′ is the distance from the vehicle center of gravity G to the direction line segment of the braking force FL ′.

Further, when the braking force FR ′ is applied to the tire 1122 on the right front wheel,
ΔMR ′ = dR ′ × FR ′
Works. DR ′ is the distance from the vehicle center of gravity G to the direction line segment of the brake force FR ′.

In each of the following documents, yaw moment is obtained by detecting any or all of parameters such as yaw angle α, yaw rate r, slip angle β, and vehicle speed of vehicle 1100 and adjusting the braking force based on these detected values. Is controlled to stabilize the behavior of the vehicle 1100 when traveling, or to improve the maneuverability by improving the turning ability.
JP 7-215190 A (Patent No. 3303500) Japanese Patent Laid-Open No. 3-112754 (Japanese Patent No. 2572856) Japanese Patent Laid-Open No. 8-310366 (Japanese Patent No. 3303605) JP-A-9-99821 (Patent No. 3116787) Japanese Patent Laid-Open No. 9-99826 (Japanese Patent No. 3132371) Hori, "Current status of electric vehicle control technology and innovation", IEICE Tokyo Section Symposium, 1998.9.18

In the field of special vehicles different from general automobiles, vehicles having a large number of axles of three or more axes are usually used.

FIG. 1 is a top view of a four-axis, eight-wheel vehicle 100.

The vehicle 100 includes a first shaft 11, a second shaft 12, and a third shaft 1 from the front to the rear of the vehicle body 101.
3. A vehicle provided with an axle of a fourth shaft 14. The first axis 11 and the second axis 12 are steered axes, and the third axis 13 and the fourth axis 14 are non-steering axes. The first shaft 11 includes left and right tires 2.
1 and 22 are provided, the left and right tires 23 and 24 are provided on the second shaft 12, and the third shaft 13 is provided.
Are provided with left and right tires 25 and 26, and the fourth shaft 14 is provided with left and right tires 27 and 28.

In such a 4-axis vehicle 100 as well as the 2-axis vehicle 1000, there is a demand for controlling the yaw moment.

In this case, the first shaft 11 and the second shaft 12 that are the front steering shafts of the four-axis vehicle 100 are combined,
Assuming that the axle 111 is equivalent to the axle 1111 that is the front steering axis of the two-axis vehicle 1000, the third axis 13 and the fourth axis 14 that are the non-steering axes on the rear side of the four-axis vehicle 100 are combined,
There is an idea that the control applied to the two-axis vehicle 1000 is used as an axle 112 equivalent to the non-steering shaft 1112 on the rear side of the two-axis vehicle 1000.

That is, as shown in FIG. 19A, the left rear wheel tires 25 and 27 of the equivalent rear axle 112 of the vehicle 100 are braked, and the yaw moment ΔML counterclockwise of the vehicle center of gravity G.
Or a brake is applied to the tires 26 and 28 on the right rear wheel of the equivalent rear axle 112 of the vehicle 100 to generate the yaw moment ΔMR clockwise around the vehicle center of gravity G.

In addition, as shown in FIG. 19B, the left front wheel tires 21 and 23 of the equivalent front axle 111 of the vehicle 100 are braked to generate the yaw moment ΔML ′ counterclockwise of the vehicle center of gravity G. Alternatively, the tires 22 and 24 on the right front wheel of the equivalent front axle 111 of the vehicle 100 are braked to generate the yaw moment ΔMR ′ clockwise around the vehicle center of gravity G.

However, when yaw moment control is simulated by regarding a plurality of (two) axles as equivalent axles in this way, the behavior correction during traveling of the vehicle 100 is not performed accurately, and the vehicle is traveling. There was a problem that the stability of the product may be impaired.

The present invention has been made in view of such circumstances, and in performing yaw moment control of a vehicle having a large number of three or more axles, the behavior during driving is accurately corrected, and the stability during driving is determined. Is to solve the problem.

The first invention is
Yaw moment control means for controlling the yaw moment of the vehicle by adjusting the braking force applied to the tires of the intermediate shaft excluding the frontmost axle and the rearmost axle of the vehicle provided with three or more axles It is characterized by that.

The second invention is the first invention,
From the front to the rear of the vehicle body, the first, second, and third axles are provided for a three-axle vehicle,
The yaw moment control means controls the yaw moment of the vehicle by adjusting the braking force applied to the tire of the second shaft that is the intermediate shaft.

The third invention is the first invention,
The first, second, third, and fourth axles provided from the front to the rear of the vehicle body are applied to a vehicle having four axles,
The yaw moment control means controls the yaw moment of the vehicle by adjusting the braking force applied to the second axis and / or the third axis tire, which is the intermediate axis.

A fourth invention is the first invention,
When the intermediate shaft is a steered shaft, the braking force applied to the tire of the intermediate shaft is adjusted according to the steering angle.

The concept of judging the braking force that can be applied to a tire is the concept of “tire friction circle”.

As shown in FIG. 2A, a driving / braking force Fbt, which is a resultant force of the driving force and the braking force, and a lateral force Fh directed in the lateral direction of the vehicle body 101 act on the tire. The resultant force Fa of the driving / braking force Fbt and the lateral force Fh is a force that finally acts on the tire. When the driving force hardly acts on the tire, the driving / braking force Fbt is equal to the braking force Fbt.
b. When the magnitude of the resultant force Fa exceeds the tire friction circle Sc, a side slip (slip) occurs in the tire. Unless the magnitude of the resultant force Fa exceeds the tire friction circle Sc, no side slip occurs in the tire.

A multi-axis vehicle provided with three or more axles, for example, the four-axis vehicle 100 shown in FIG. 1 has a long vehicle body length, and therefore, the frontmost first shaft 11 and the rearmost fourth shaft separated from the center of gravity G of the vehicle. A strong lateral force Fh may act on the tires 21, 22, 27, 28 of the shaft 14 in the lateral direction of the vehicle body. For example, as shown in FIG. 3, when the vehicle 100 is lane-changed while traveling at high speed and the steering in a sudden and opposite direction is continuously performed, the yaw angle α changes in a vibration manner, and the frontmost tire 21 and 22, the amount of lateral deformation of the rearmost tires 27 and 28 is extremely large,
A strong lateral force Fh acts. In this situation, the brake force Fb is adjusted and the yaw moment ΔM
2 (b), the magnitude of the resultant force Fa is the friction circle S of the tire.
c is exceeded, and the side slip is likely to occur between the frontmost tires 21 and 22 and the rearmost tires 27 and 28. As shown in FIG. 2B, the braking force Fb (driving / braking force Fbt) that can be applied to the frontmost tires 21, 22 and the rearmost tires 27, 28, that is, the resultant force Fa is applied to the tire friction circle Sc. The maximum braking force that is not exceeded is very small.

On the other hand, in the same situation as FIG. 3, the lateral force Fh acting on the tires 23, 24, 25, and 26 of the second shaft 12 and the third shaft 13, which are intermediate axles on the front and rear sides near the vehicle center of gravity G Is relatively small. That is, even if the yaw angle α changes in vibration, the intermediate tires 23, 24, 25,
The amount of lateral deformation of 26 is relatively small, and the acting lateral force Fh is relatively small. For this reason, even if the yaw moment is controlled by applying the same amount of braking force Fb, the resultant force Fa is less than the friction circle Sc of the tire, and there is a margin in braking force, even if a strong brake is applied. Side slip is unlikely to occur. As shown in FIG. 2 (c), the intermediate tires 23, 24,
The braking force (driving / braking force Fbt) that can be applied to 25 and 26, that is, the braking force that is maximum within a range where the resultant force Fa does not exceed the tire friction circle Sc is very large. For this reason, when performing yaw moment control, unstable behavior such as slip is less likely to occur, and the vehicle 100 can be driven stably.

Therefore, the present invention controls the yaw moment of the vehicle 100 by adjusting the braking force applied to the tire of the intermediate shaft excluding the frontmost axle and the rearmost axle of the vehicle 100 provided with three or more axles. (First invention).

As illustrated in FIG. 4, the first shaft 11, the second shaft 12,
In the case of the vehicle 100 having the number of axles 3 provided with the axle of the third shaft 13, the yaw moment of the vehicle 100 is adjusted by adjusting the braking force applied to the tires 23 and 24 of the second shaft 12 that is the intermediate shaft. (Second invention).

As illustrated in FIG. 5, the first shaft 11, the second shaft 12,
In the vehicle 100 with four axles provided with the axles of the third shaft 12 and the fourth shaft 14, the braking force applied to the tire of the second shaft 12 and / or the third shaft 13 as an intermediate shaft is adjusted. By doing so, the yaw moment of the vehicle 100 is controlled (third invention).

As illustrated in FIG. 5, when the intermediate shaft is a steered shaft (second shaft 12), the steering angle of the tire corresponding to the steering angle of the steering wheel or the like, that is, the steering angle corresponding to this steering angle. δ,
The braking force applied to the intermediate tires 23 and 24 is adjusted according to δ ′. This is because even when the same yaw moment ΔM is applied, the lengths d and d ′ of the arm of the moment differ depending on the turning angles δ and δ ′, and the braking forces Fb and Fb ′ differ accordingly. This is because the braking forces Fb and Fb ′ must be changed according to the angles δ and δ ′. Therefore, in order to obtain a constant yaw moment ΔM regardless of the magnitude of the steering angle γ, it is necessary to correct the braking force Fb according to the steering angle γ.

According to the present invention, as seen in the four-axis vehicle 100 illustrated in FIG. 5, the multi-axis vehicle 100 having three or more axles is used when the yaw angle changes in a vibrational manner, such as when a lane change is performed. Has a characteristic that the lateral force Fh acting on the tires 23, 24, 25, 26 of the intermediate shafts 12, 13 is small. In view of this characteristic, the braking force applied to the tires 23, 24, 25, and 26 of the intermediate shafts 12 and 13 is adjusted to control the yaw moment ΔM. Therefore, the stability and maneuverability (turning ability) of the vehicle 100 are controlled. Will improve.

For example, as shown in FIG. 3, the lateral force Fh acting on the tires 21, 22, 27, and 28 on the frontmost first shaft 11 and the rearmost fourth shaft 14 was strong, and it was easy to slip. However, the tires 2 of the second shaft 12 and the third shaft 12 which are intermediate shafts having a weak lateral force Fh and difficult to slide sideways.
3. The braking force Fb is applied to 3, 24, 25, and 26 to control the yaw moment ΔM, so that the tire does not slip sideways, that is, the vehicle as a whole causes unstable behavior such as spin and drift out. There is no. For this reason, even if it is a multi-axis vehicle, it can be extremely stable, equal to or higher than that of a two-axis vehicle, and can improve the stability when the vehicle travels, and can also improve the turning ability when turning the vehicle. it can.

Note that the multi-axle vehicle 100 having three or more axles has tires 21, 22 on the front axle 11 and the rear axle 14 due to the movement of the center of gravity caused by pitching during acceleration and deceleration.
Although the loads 27 and 28 change greatly, the intermediate shafts 12 and 13 have the characteristic that the influence of pitching is small and a stable load can always be maintained. Therefore, the braking force can be stably applied to the tire during acceleration and deceleration, and there is an advantage that the control accuracy is further improved.

Embodiments of a yaw moment control device for a vehicle according to the present invention will be described below with reference to the drawings.

The vehicle 100 assumed in the embodiment is a four-axis, eight-wheel vehicle 10 as illustrated in FIG.
0. FIG. 5 is a top view of the vehicle 100 and shows the configuration of the steering system device.

The vehicle 100 includes a first shaft 11, a second shaft 12, and a third shaft 1 from the front to the rear of the vehicle body 101.
3. A vehicle provided with an axle of a fourth shaft 14. The first axis 11 and the second axis 12 are steered axes, and the third axis 13 and the fourth axis 14 are non-steering axes. The first shaft 11 includes left and right tires 2.
1 and 22 are provided, the left and right tires 23 and 24 are provided on the second shaft 12, and the third shaft 13 is provided.
Are provided with left and right tires 25 and 26, and the fourth shaft 14 is provided with left and right tires 27 and 28. Note that the distances between the axles 11, 12, 13, and 14 are set substantially evenly. In addition, in vehicles such as consumer trucks, there are vehicles in which the front wheels and the rear wheels are each composed of two wheels arranged close to each other. This is a two-axis, four-wheel vehicle. Therefore, it is not a multi-axis vehicle that is the subject of the present invention.

FIG. 6 is a configuration diagram of a drive system device of the vehicle 100. In the present embodiment, an all-wheel drive vehicle is assumed.

  That is, the input shaft of the torque converter 2 is connected to the output shaft of the engine 1.

The input shaft of the transmission 3 is connected to the output shaft of the torque converter 2. The output shaft of the transmission 3 is connected to the input shaft of the drive gear 4. The output shaft of the drive gear 4 is connected to the common drive shaft 5. The common drive shaft 5 has axles 11, 12, 13, 1
4 are connected to the input shafts of differential gears 11D, 12D, 13D, and 14D. For this reason, the driving force of the engine 1 is transmitted to the tires 21, 22, 23, 24, 25, 26, 27, and 28 via the axles 11, 12, 13, and 14, respectively.

  FIG. 7 is a block diagram showing the device configuration of the control system of the embodiment.

The control target is a multi-axis vehicle 100. In the 4-axis vehicle 100, by adjusting the braking force applied to the tires of the second shaft 12 and / or the third shaft 13 that are intermediate shafts,
The yaw moment of the vehicle 100 is controlled.

The yaw angle control unit 40 estimates the state of the vehicle 100 based on a sensor signal such as the steering angle γ detected by the sensor unit 70 of the vehicle 100, and is necessary for improving the vehicle 100 in stable running or turning ability. A yaw moment command value, that is, a yaw moment target value ΔMd,
Output to the yaw moment controller 50. The sensor signal detected by the sensor unit 70 and input to the yaw angle control unit 40 is a driving operation or physical motion data of the vehicle 100 to be controlled, and a steering angle sensor, a tire rotation sensor, and a vehicle body acceleration for measuring them. The steering angle γ, the vehicle body yaw rate r, the vehicle speed V, the slip angle β, and the like are obtained directly from the sensor signals from the sensor, the vehicle body yaw rate sensor, or indirectly by estimation calculation.

The yaw moment control unit 50 obtains a braking force to be applied to the intermediate shaft of the vehicle 100 according to the target value ΔMd of the yaw moment, adjusts the brake control valve so that the braking force is obtained, and the vehicle 100 Control the yaw moment. The yaw moment control unit 50
Based on the selection signal, it is determined whether to adjust the brake of one or both of the second shaft 12 and the third shaft 13 which are intermediate shafts, and the brake force of the determined axle is adjusted. When it is determined that the braking force of the second shaft 12 that is the steering shaft is to be adjusted, the braking force is obtained according to the steering angle γ of the vehicle 100.

In the present embodiment, as illustrated in FIG. 5, the left and right tires 2 on the intermediate shaft, for example, the third shaft 13.
By adjusting the braking forces FbL and FbR of Nos. 5 and 26, the yaw moment ΔM with the clockwise direction of the center of gravity G of the vehicle as the positive direction,
ΔM = d0 × (FbR−FbL)
Is generated.

  FIG. 8 is a block diagram showing an example of the configuration of the control system apparatus shown in FIG.

As shown in FIG. 8, the apparatus of the embodiment mainly includes a sensor unit 70, a selection unit 80, a controller 30, a second axis left automatic control valve 55, a second axis right automatic control valve 56, A 3-axis left automatic control valve 57 and a third-axis right automatic control valve 58 are configured.

The controller 30 includes a yaw angle control unit 40, a distribution unit 51, a second axis brake air calculation unit 52,
A third shaft brake air pressure calculation unit 53 and a brake cylinder pressure control unit 54 are included. A distribution unit 51, a second axis brake air calculation unit 52, a third axis brake air pressure calculation unit 53,
Brake cylinder pressure control unit 54, second axis left automatic control valve 55, second axis right automatic control valve 56,
The third axis left automatic control valve 57 and the third axis right automatic control valve 58 correspond to the yaw moment control unit 50 in FIG.
It corresponds to the component of.

Next, the configuration of the brake system device of the embodiment will be described with reference to FIG. The brake device according to the embodiment converts the high-pressure air generated by the pneumatic pressure source into hydraulic pressure, and operates the piston of the brake cylinder to the side that presses against the brake disk by hydraulic pressure to brake the wheel. It consists of Note that the vehicle 10 to be controlled in this embodiment.
0 is much larger in weight and moment of inertia than ordinary automobiles, and its attitude change response is slow. Therefore, even if the yaw moment is generated and the attitude of the vehicle 100 is changed by using an air brake device that is said to be relatively slow in response, the control accuracy sufficient to improve the stability and turnability of the vehicle. Is obtained.

As shown in FIG. 9, eight tires 21, 22, 23, 24, 25, 26, 27, 28
Respectively, brake cylinders 91, 92, 65, 66, 67, 68, 93,
94 is provided.

Among these brake cylinders, automatic control valves 55, 56, 57, and 58 are respectively attached to the brake cylinders 65, 66, 67, and 68 of the second shaft 12 and the third shaft 13 that are intermediate shafts.

The high-pressure air passes from the air tank 60 via the pipe line 62, and the branch pipe lines 62a, 62b, 62
c, 62d, and supplied to the intermediate shaft automatic control valves 55, 56, 57, 58. When the automatic control valves 55, 56, 57, 58 are opened, the automatic control valves 55, 56, 57,
58 passes through each of the brake cylinders 65, 66, 67, 68 of the second shaft 12 and the third shaft 13 which are intermediate shafts.

Further, the brake cylinders 65, 66, 67, 6 of the second shaft 12 and the third shaft 13 which are intermediate shafts.
8 is supplied with air having a pressure corresponding to the amount of depression of the brake pedal 90. That is,
The high-pressure air passes from the air tank 60 via the pipe line 62 and via the branch pipe lines 62e and 62f.
The brake valve 61 is supplied. The brake valve 61 operates by depressing the brake pedal 90. From the brake valve 61, air having a pressure corresponding to the amount of depression of the brake pedal 90 is supplied to the pipelines 63A and 63B, and the branch pipelines 63c and 6 of the pipeline 63A are supplied.
It is supplied to the left and right automatic control valves 55 and 56 of the second shaft 12 through the intermediate shaft 3d, and the third shaft 13 of the intermediate shaft through the branch pipes 63e and 63f of the pipe 63B. The left and right automatic control valves 57 and 58 are supplied. When the automatic control valves 55, 56, 57, and 58 are opening, the air that has passed through the automatic control valves 55, 56, 57, and 58 is the second shaft 12 and the third shaft that are intermediate shafts. 13 brake cylinders 65, 66, 67, 68 are supplied.

When the brake pedal 90 is depressed, the controller 30 automatically controls the valve 55,
Control is performed so that air having a pressure corresponding to the depression operation amount of the brake pedal 90 is supplied to the brake cylinders 65, 66, 67 and 68 from 56, 57 and 58.

On the other hand, the brake cylinders 91, 92, 93, 94 of the first shaft 11 and the fourth shaft 14 are supplied with air having a pressure corresponding to the depression amount of the brake pedal 90. That is, high-pressure air is supplied from the air tank 60 to the brake valve 61 via the pipe line 62 and the branch pipe lines 62e and 62f. From the brake valve 61, air having a pressure corresponding to the operation amount of the brake pedal 90 is supplied to the pipe lines 63A and 63B, and the branch pipe line 63g of the pipe line 63A,
Is supplied to the left and right brake cylinders 91 and 92 of the first shaft 11 via 63h,
The left and right brake cylinders 9 of the fourth shaft 13 via the branch pipes 63i and 63j of the pipe 63B.
3 and 94. When the brake pedal 90 is depressed, air having a pressure corresponding to the depression operation amount of the brake pedal 90 is supplied to the brake cylinders 91, 92, 93, 94.

The automatic control valves 55, 56, 57, 58 are provided with three exciting coils 69a, 69b, 69c. Each of the automatic control valves 55, 56, 57, 58 has a brake cylinder 6
A pressure sensor 69d for detecting the air pressures P2L, P2R, P3L, and P3R of 5, 66, 67, and 68 is provided. The brake cylinder pressure control unit 54 of the controller 30 includes a brake cylinder 65, a second shaft brake air pressure calculation unit 52, and a third shaft brake air pressure calculation unit 53, which will be described later.
The target air pressures P2Ld, P2Rd, P3Ld, P3Rd of 66, 67, 68 are input, and the actual detected air pressure P2L of the brake cylinders 65, 66, 67, 68 from the pressure sensor 69d,
By inputting P2R, P3L, P3R, command signals i () to the exciting coils 69a, 69b, 69c of the automatic control valves 55, 56, 57, 58 so that the target air pressures P2Ld, P2Rd, P3Ld, P3Rd are obtained. ia, ib, ic) are output. A command signal ia for increasing the air pressure is applied to the excitation coil 69a, and a command signal ib for maintaining the air pressure at the current pressure value is applied to the excitation coil 69b. A command signal ic for reducing the air pressure is added.

When the command signal ia is applied to the excitation coil 69a for increasing pressure command, the excitation coil 69a is excited, whereby the original pressure from the air tank 60 is reduced to the brake cylinders 65, 66, 67, 6
The automatic control valves 55, 5 so that the air pressures P2L, P2R, P3L, P3R are increased by flowing into
6, 57, 58 operate. Further, when the command signal ib is applied to the holding command exciting coil 69b, the exciting coil 69b is excited, shuts off the flow of air on the automatic control valve output side and air on the brake cylinder 65, 66, 67, 68 side. The automatic control valves 55, 56, 57 and 58 operate so as to maintain the pressures P2L, P2R, P3L and P3R. Further, when a command signal ic is applied to the excitation coil 69c for pressure reduction command, the excitation coil 69c is excited, thereby automatically controlling the air pressures P2L, P2R, P3L, P3R so as to reduce the air pressures P2, L, P3R. , 58 operates. The brake pedal 90 is provided with a sensor 72 that detects a depression operation amount Sb of the brake pedal 90. The detection signal Sb of the sensor 72 is input to the brake cylinder pressure control unit 54 of the controller 30. Brake cylinder pressure controller 5 of the controller 30
4 determines whether or not the brake pedal 90 is operated based on the input signal Sb.
When the brake pedal 90 is not operated, as described above, the target air pressure P2Ld,
Excitation coil 6 of automatic control valves 55, 56, 57, 58 to obtain P2Rd, P3Ld, P3Rd
A command signal i is output to 9a, 69b and 69c. When the brake pedal 90 is operated, the brake pedal 90 is operated regardless of the command input of the target air pressures P2Ld, P2Rd, P3Ld and P3Rd. Automatic control valves 55, 56, 57, so as to obtain a corresponding air pressure
The command signal i for 58 excitation coils 69a, 69b, 69c is turned off. This is based on the idea that the braking force according to the manual operation based on the operator's intention is prioritized over the braking force automatically applied regardless of the operator's intention. The command signals ia, ib, ic are not applied to any of the three excitation coils 69a, 69b, 69c of the automatic control valves 55, 56, 57, 58, and all of the three excitation coils 69a, 69b, 69c are excited. If not, the automatic control valves 55, 56, 57 and 58 function as simple piping connecting the brake cylinders 65, 66, 67 and 68 and the brake valve 61. When the brake pedal 90 is depressed in a state where none of the exciting coils 69a, 69b, 69c of the automatic control valves 55, 56, 57, 58 is excited, high-pressure air from the air tank 60 flows into the brake valve 61, and the brake The air of the pressure adjusted by the valve 61 passes through the automatic control valves 55, 56, 57, 58 as it is, and the brake cylinders 65, 66, 67, 68.
Flow into. Similarly, exciting coils 69a, 69b, 6 of the automatic control valves 55, 56, 57, 58
When none of 9c is energized, when the foot is released from the brake pedal 90 that was stepped on and released, the high pressure air that has filled the brake cylinders 65, 66, 67, and 68 is taken along the path indicated by L. The automatic control valves 55, 56, 57, and 58 flow backward as they are, and the brake valve 6
1 to the atmosphere. Note that the automatic control valves 55, 56, 57, and 58 of the present embodiment are configured so that two or more exciting coils are not energized simultaneously. In addition, the automatic control valve 55,
56, 57, and 58 are configured to be opened and closed at a sufficiently high speed by ON / OFF of excitation. The brake cylinder pressure control unit 54 of the controller 30 generates and outputs a command signal i by the following algorithm. For example, it is assumed that a command signal P3Rd indicating the target air pressure is input. When the command signal P3Rd is input, the target air pressure P3Rd indicated by the command signal and the current air pressure P3R indicated by the pressure sensor detection signal input from the corresponding third axis right automatic control valve 58 are And exciting coils 69a and 69 based on the comparison result.
Either one of b and 69c is excited.

Thereafter, the following processing is repeated until the current air pressure P3R matches the target air pressure P3Rd.

1) If P3R <P3Rd, the exciting coil 69a of the third axis right automatic control valve 58 is excited to increase the pressure.

2) If P3R is approximately equal to P3Rd, the exciting coil 69b of the third axis right automatic control valve 58
To maintain air pressure.

3) If P3R> P3Rd, the exciting coil 69c of the third axis right automatic control valve 58 is excited to reduce the pressure. Next, processing performed by the yaw angle control unit 40 will be described with examples. FIG. 10 shows an example of the behavior of the vehicle 100 when the control of the present invention is not performed. FIG. 10A shows that the vehicle 100 passes from the exit of the tunnel 1000 to the tunnel 1000.
The scene that received a strong crosswind at the moment of going outside. At the moment of passing through the tunnel 1000, a lateral wind is first received on the front left side of the vehicle 100, so that a right lateral force Fh is generated in the front tires 21, 22, 23, 24 even though the driver does not perform a steering operation. , Body 101
, A yaw moment ΔMn is generated clockwise (clockwise), and a yaw rate r is generated.

If the driver does not operate the steering wheel as it is, the vehicle 100 changes its posture in the same clockwise direction (right direction) and turns from the straight direction to the oblique direction as shown in FIG. Will change. At this time, the driver feels as if the steering wheel is suddenly taken.

In order to return the vehicle 100 to the straight direction, the driver cancels the influence of the received disturbance,
That is, it is necessary to correct the course and posture of the vehicle 100 by turning the steering wheel in a direction to cancel the yaw moment ΔMn and yaw rate r generated by the disturbance.

  In view of such a case, the yaw angle control unit 40 executes the following processing.

That is,
1) The slip angle β is estimated and calculated from the yaw rate r and yaw acceleration of the vehicle 100 to be controlled detected by the sensor unit 70. Note that the sensor unit 70 may be configured to directly detect the slip angle.

2) Next, the steering angle γ of the steering handle of the vehicle 100 to be controlled is read from the sensor unit 70.

3) Next, based on the magnitude of the steering angle γ, the ideal magnitude of the slip angle βd is obtained.

Here, data of an ideal slip angle βd corresponding to the magnitude of the steering angle γ is stored in advance. This is because, if the magnitude of the steering angle γ is determined, the ideal value or range of the ideal slip angle βd that allows the vehicle 100 to travel stably or travel with good turnability is uniquely determined. Because. As in the case of FIG. 10, when the vehicle 100 is still traveling in the tunnel 1000 and the vehicle 100 is traveling straight with the steering angle γ kept near neutral,
It is determined that the ideal slip angle βd should be zero.

4) Next, it is determined whether or not a deviation of a predetermined value or more has occurred between the ideal slip angle βd and the actual slip angle β.

As in the case of FIG. 10, when the vehicle 100 exits the tunnel 1000, the vehicle 100 receives a cross wind, and as described above, the yaw moment ΔMn and the yaw rate r are generated due to the disturbance,
A difference occurs between the direction of the vehicle body 101 and the traveling direction, and the actual slip angle β deviates from zero.

5) Next, when a deviation of a predetermined amount or more occurs between the ideal slip angle βd and the actual slip angle βd, the disturbance yaw moment ΔMn and yaw rate r are canceled in the vehicle body 101, and the slip angle β Is determined to be given a yaw moment ΔMd for making the ideal slip angle βd (zero).

6) Next, from the detection signal of the sensor unit 70, the yaw moment ΔMn and yaw rate r of the disturbance applied to the vehicle body 101 are estimated or directly detected, and these are canceled out, and the slip angle β is an ideal slip angle. A target value ΔMd of the yaw moment that should be given to the vehicle 100 required to make βd (zero) is calculated and output to the distribution unit 51 of the controller 30 as a command value.

FIG. 10 is an example of maintaining the straight traveling state of the vehicle 100. Next, referring to FIG.
A case where the vehicle 100 is turning will be described.

FIG. 11 shows the trajectories LN0, LN1, LN2, and LN3 when the vehicle 100 is turning right.
These are trajectories when the same amount of steering angle γ is given.

The trajectory LN0 is a trajectory when the control of the present invention is not performed, and indicates a trajectory in a range where the road surface state is good and the load is appropriate. On the other hand, the trajectory LN3 is a trajectory when the control of the present invention is not performed, and indicates a trajectory when the road surface state is bad or the load exceeds an appropriate range. That is, when the slip angle β is extremely larger than the steering angle γ and a large deviation occurs between the ideal slip angle βd and the actual slip angle β,
The vehicle 100 may drift greatly in the right direction or spin out.

The locus LN1 is a locus with an understeer tendency than the locus LN0. The locus LN1 has a smaller slip angle β than the locus LN0. The locus LN2 is a locus having an oversteer tendency than the locus LN0. The locus LN2 has a larger slip angle β than the locus LN0.

The control performed by the yaw angle control unit 40 when the vehicle turns is, for example, as follows.

a) When it is desired to improve the running stability when the vehicle turns by giving the vehicle 100 straight travel, the locus L
A counterclockwise yaw moment ΔML is calculated for the vehicle body 101, which is required for turning along a locus LN1 that is understeer than N0, and a yaw moment command value ΔMd that uses this as a target value is output. In order to perform such control, a smaller value is set in advance as the ideal slip angle βd with respect to the steering angle γ.

b) Necessary for turning the vehicle 100 along a locus LN2 that is oversteered than the locus LN0 when it is desired to improve the maneuverability when turning the vehicle by reducing the turning radius of the vehicle by giving the turning ability to the vehicle 100. Then, a clockwise yaw moment ΔMR is calculated on the vehicle body 101, and a yaw moment command value ΔMd having this as a target value is output. In order to perform such control, a larger value is set in advance as the ideal slip angle βd with respect to the steering angle γ.

c) When the road surface condition is deteriorated or the load exceeds the appropriate range, there is a possibility that a large shift occurs between the ideal slip angle βd of the vehicle 100 and the actual slip angle β, and the locus LN3 is traced. If it is determined, a yaw moment counterclockwise for canceling drift and spin-out behavior is calculated, and a yaw moment command value ΔMd having this as a target value is output. In addition,
The trajectory to be returned depends on the setting of the ideal slip angle βd with respect to the steering angle γ. When it is desired to return to the trajectory of the understeer tendency, the ideal slip angle βd should be set to a smaller value with respect to the steering angle γ. The ideal value of the slip angle βd with respect to the steering angle γ may be set to a larger value.

Next, the selection unit 80 will be described.

The selection unit 80 is provided to select and operate the target axle to which the braking force Fb is to be applied. The selection part 80 is comprised by the manual switch provided in the operation panel of the driver's seat, for example.

In the case of a four-axis, eight-wheel vehicle 100, the second shaft 12, which is an intermediate shaft, the tire 23 of the third shaft 13,
Brake force Fb is applied to 24, 25, and 26. However, in the case of the multi-axis vehicle 100, even when the same intermediate shaft is used, the brake is applied to the second shaft 12 that is the steering shaft, and the third shaft 13 that is the non-steer shaft is applied to the brake. As described later, the purpose and effect are different.

Also, the purpose and effect differ between when the brake is applied to all of the intermediate shafts 11 and 12 and when only one of the intermediate shafts is braked. In view of such circumstances, the selection unit 80 is provided to select an axle to be braked depending on the situation.

The operation panel is provided with a manual switch for selecting two types of modes, “all intermediate axis braking” and “single axis braking”. The “all intermediate shaft braking” mode is a mode selected when braking is applied to all the intermediate shafts 11 and 12. The “single-axis braking” mode is a mode selected when braking only one intermediate shaft. In the case of a four-axis vehicle, the “single-axis braking” mode is a mode for selecting “second axis”, that is, a mode for selecting to brake the second axis 12;
The mode is further divided into a mode for selecting “third axis”, that is, a mode for selecting braking on the third axis 13. The purpose and effect of selecting each mode will be described below.

(1) When the “all intermediate shaft braking” mode is selected, as described above with reference to FIG. 2, the braking force F that can be generated by one tire.
The maximum value of b is constrained by the friction circle Sc. For this reason, in the case of a large number of intermediate shafts, that is, a four-axis vehicle 100, if both brakes of the second shaft 12 and the third shaft 13 are operated simultaneously,
It is possible to generate a stronger yaw moment ΔM than when the brakes are individually operated on the individual intermediate shafts. In addition, since the maximum braking force that can be generated by the sum of all the intermediate shafts (second shaft 12 and third shaft 13) is large, the adjustment range of the braking force is wide, and the entire vehicle can be adjusted by automatically adjusting the braking force. There is an advantage that the adjustment range of the intensity of the yaw moment ΔM that can be generated in the above is widened.

However, on the other hand, since the braking force is applied to a large number of tires of a plurality of intermediate shafts, the braking force acting on the entire vehicle becomes strong, and as a result, even though the driver does not step on the brake pedal 90, In a vehicle with a public road running specification, the vehicle 100 may decelerate rapidly without turning on the brake light. For this reason, the speed of the vehicle 100 may drop, and the work efficiency may be impaired even temporarily, or may affect other vehicles traveling on public roads. Therefore, it is desirable to use this mode in situations where deceleration is possible or in places other than public roads. Note that the deceleration of the vehicle 100 may be detected from the detection signal of the sensor unit 70, and the brake light may be automatically turned on when the deceleration exceeds a predetermined value.

(2) When “Single Axis Braking” Mode is Selected In situations where rapid deceleration is not desirable, such as when driving on public roads, it is desirable to use this “single axis braking” mode, which has a relatively small braking force. In the “single axis braking” mode, when the “second axis” mode that is the steering axis is selected, and when the “third axis” mode that is the non-steering axis is selected,
The generated yaw moment ΔM determines the value of the steering angle γ during control and the role of the braking wheel (= outer wheel,
Care must be taken because the behavior of the vehicle varies depending on the inner ring.

This will be described with reference to FIGS.

FIG. 12 is a diagram comparing the yaw moments generated when the brakes are applied to the tires of the intermediate shafts when the vehicle 100 turns right as shown in FIG. 11.

The tires 23, 24, 25, 26 of the intermediate shafts 12, 13 of the vehicle 100 have the same size F
It is assumed that zero braking force F2L, F2R, F3L, F3R acts. The distance from the vehicle center of gravity G to the left and right tires is d0.

The length of the arm of the yaw moment from the vehicle center of gravity G to the left tire 23 of the second shaft 12 is d2L, and the length of the arm of the yaw moment from the vehicle center of gravity G to the right tire 24 of the second shaft 12 is d2R.
The length of the arm of the yaw moment from the center of gravity G of the vehicle to the left tire 25 of the third shaft 13 is d3L.
And the length of the arm of the yaw moment from the center of gravity G of the vehicle to the right tire 26 of the third shaft 13 is d3R.
And

For example, in order to follow the trajectory LN1 of the understeer tendency for the purpose of stabilizing the behavior of the vehicle 100, the brake force F0 is applied only to the second shaft 12 and the counterclockwise yaw moment ΔML (F2L
When trying to generate (× d2L), a yaw moment stronger than the yaw moment (F3L × d3L (= d0)) when the same braking force F0 is applied only to the third shaft 13 is obtained.

This is because the moment arm d2L of the braking force F2L applied to the left tire 23 on the outer wheel side (having the function of stabilizing) when the second shaft 12 as the steering shaft is steered to the right and is turning to the right.
This is because the steering angle γ, that is, the turning angle δ of the tire, is longer than the moment arm d3L (= d0) of the braking force F3L applied to the same left tire 25 of the third shaft 13 that is a non-steering shaft. Therefore, when the vehicle 100 is turned with an understeer tendency in the “single-axis braking” mode, the yaw moment Δ that can be generated in the entire vehicle by widening the adjustment range of the braking force.
When you want to have a wide adjustment range for the M strength, the "second axis" has a relatively strong braking force.
It is desirable to select a mode. Further, when the vehicle 100 is turned with an understeer tendency in the “single-axis braking” mode and the braking force is weak and the vehicle 100 is not desired to be decelerated, the braking force is relatively weak. It is desirable to select the “mode”.

Conversely, in order to follow the trajectory LN2 of the oversteer tendency for the purpose of improving the turning ability of the vehicle 100,
A braking force F0 is applied only to the second shaft 12, and the clockwise yaw moment ΔMR (F2R x d2R)
When the same braking force F0 is applied only to the third shaft 13, a yaw moment that is weaker than the yaw moment (F3R × d3R (= d0)) is obtained. this is,
The moment arm d2R of the braking force F2R applied to the right tire 24 on the inner ring side (which has a function of reducing the turning radius) when the second shaft 12 that is the steering shaft is steered to the right and is turning right is:
This is because the steering angle γ, that is, the tire turning angle δ, is shorter than the moment arm d3R (= d0) of the braking force F3R applied to the same right tire 26 of the third shaft 13 that is a non-steering shaft. Therefore, in the case of turning the vehicle 100 in the “single-axis braking” mode with a tendency to oversteer, the yaw moment Δ that can be generated in the entire vehicle by widening the adjustment range of the braking force.
“Axis 3” is a relatively strong brake force for situations where it is desired to have a wide adjustment range for the strength of M.
It is desirable to select a mode. Further, when the vehicle 100 is turned with an oversteer tendency in the “single-axis braking” mode and the braking force is weakened and the vehicle 100 is not desired to be decelerated, the “second axis” mode is selected. It is desirable.

Further, when the “third axis” mode in which the braking force is applied to the third axis 13 of the non-steering axis is selected, the yaw moment does not fluctuate due to the influence of the steering angle angle γ, that is, the tire turning angle δ. For this reason, the third shaft 13 has an advantage that it can stably generate a constant maximum yaw moment without depending on the steering angle γ when the vehicle is turning. Therefore, it is desirable to select the “third axis” mode in a situation where it is necessary to generate a constant maximum yaw moment stably when the vehicle is turning.

In the above description, the selection unit 80 allows the operator to arbitrarily select all the intermediate axes.
Alternatively, either one of the intermediate shafts is selected, but it is also possible for the controller 30 to automatically perform such selection according to the state of the vehicle 100. For example, vehicle 1
Depending on the situation, 00 is automatically selected as the “second axis” mode and turns with an understeer tendency, or the “third axis” mode is automatically selected as an oversteer tendency. Is also possible.

  Next, the distribution unit 51 of the controller 30 will be described.

The distribution unit 51 inputs the mode selected by the selection unit 80 and the yaw moment command value ΔMd output from the yaw angle control unit 40, and the yaw moment target value Δ indicated by the command value.
A processing unit that distributes Md to the intermediate axis designated in the selected mode. In the distribution unit 51,
In the processing shown below, each of the second axes to be generated on the second axis 12 and the third axis 13 which are intermediate axes.
An axis yaw moment command value ΔM2 and a third axis yaw moment command value ΔM3 are calculated.

1) When neither the second axis 12 nor the third axis 13 is selected by the selection unit 80,
ΔM2 = ΔM3 = 0 (31)
And
2) When only the second axis 12 is selected by the selection unit 80,
ΔM2 = ΔMd, ΔM3 = 0 (32)
And However, when the yaw moment target value ΔMd exceeds the maximum yaw moment that can be generated on the second shaft 12 at the steering angle γ at that time, the yaw moment reaches a peak and becomes saturated.

3) When only the third axis 13 is selected by the selection unit 80,
ΔM3 = ΔMd, ΔM2 = 0 (33)
And However, when the yaw moment target value ΔMd exceeds the maximum yaw moment that can be generated on the third axis 13, the yaw moment reaches a peak and becomes saturated.

4) When the selection unit 80 selects the second axis 12 and the third axis 13 at the same time, the yaw moment is mainly distributed to the third axis 13 that is not affected by the steering angle γ and is generated on the third axis 13. The shortage of the obtained yaw moment is covered by the second axis 12. That is,
(A) When the yaw moment target value ΔMd is smaller than the maximum value ΔM3max of the yaw moment ΔM3 that can be generated on the third axis 13,
ΔM3 = ΔMd, ΔM2 = 0 (34)
And

(B) When the yaw moment target value ΔMd exceeds the maximum value ΔM3max of the yaw moment ΔM3 that can be generated on the third shaft 13,
ΔM3 = ΔM3max, ΔM2 = ΔMd−ΔM3max (35)
And However, the target value ΔM2 of the yaw moment of the second axis is the second value at the steering angle γ at that time.
If the maximum yaw moment that can be generated on the shaft 12 is exceeded, the yaw moment reaches a peak and becomes saturated.

The second axis yaw moment command value ΔM2 and the third axis yaw moment command value ΔM3 calculated as described above are output to the second axis brake air pressure calculation unit 52 and the third axis brake air pressure calculation unit 53, respectively.

Next, processing performed by the second axis brake air pressure calculation unit 52 and the third axis brake air pressure calculation unit 53 will be described.

The second axis brake air pressure calculation unit 52 inputs the steering angle γ of the steering wheel detected by the sensor 71 of the sensor unit 70 and the second axis yaw moment command value ΔM2 calculated by the distribution unit 51. Then, the target air pressures P2Ld and P2Rd of the second shaft left brake cylinder 65 and the second shaft right brake cylinder 66 necessary for obtaining the yaw moment target value ΔM2 at the current steering angle γ are calculated and calculated. The target air pressures P2Ld and P2Rd are output to the brake cylinder pressure control unit 54.

The third-axis brake air pressure calculation unit 53 inputs the third-axis yaw moment command value ΔM3 calculated by the distribution unit 51, and a third-axis left brake cylinder 67 necessary for obtaining the yaw moment target value ΔM3. Calculate target air pressures P3Ld and P3Rd of the third axis right brake cylinder 68,
The calculated target air pressures P3Ld and P3Rd are output to the brake cylinder pressure control unit 54.

(Processing performed by the third axis brake air pressure calculation unit 53)
FIG. 13 is a view of the vehicle 100 as seen from the top as in FIGS. 5 and 12. By applying braking forces F3L and F3R to the left and right tires 25 and 26 of the third shaft 13 respectively, It is a figure explaining generation | occurrence | production of moment (DELTA) M3.

Note that, depending on the vehicle 100, the position of the center of gravity G does not necessarily exist at the center between the left and right tires. If the distance from the vehicle center of gravity G to the center line of the left tire is dL, and the distance from the vehicle center of gravity G to the center line of the right tire is dR, the yaw moment by the braking force F3L acting on the left tire 25 of the third shaft 13 The arm length is dL, and the arm length of the yaw moment by the braking force F3R acting on the right tire 26 of the third shaft 13 is dR.

The yaw moment ΔM3 generated in the clockwise direction (right direction) of the center of gravity G of the vehicle by the braking forces F3L and F3R acting on the third axis left tire 25 and the third axis right tire 26, respectively,
ΔM3 = dR · F3R−dL · F3L (1)
It becomes.

Therefore, if the polarity of the yamment ΔM3 in the equation (1) is positive, the vehicle 100
If a yaw moment in the clockwise direction is generated in the vehicle 100 and the polarity of the yam moment ΔM3 in the equation (1) is negative, a counterclockwise yaw moment is generated in the vehicle 100.

FIG. 14 is a flowchart showing a processing procedure performed by the third brake air pressure calculation unit 53 and the second brake pressure calculation unit 52.

That is, while reading the absolute value of the input third axis yamment target value ΔM3,
It is determined whether the polarity is positive or negative (step 201). As a result, if the absolute value of the third axis yaw moment target value ΔM3 is negligibly small, the third axis left tire 25,
The brake forces F3L and F3R to be applied to the third shaft right tire 26 are regarded as zero, and the target air pressure P of the corresponding third shaft left brake cylinder 67 and third shaft right brake cylinder 68 is assumed.
3Ld and P3Rd are set to zero (step 203).

If the polarity of the third axis yaw moment target value ΔM3 is positive, that is, ΔM3> 0, Δ
The target air pressures P3Ld and P3Rd of the third axis left brake cylinder 67 and the third axis right brake cylinder 68 are calculated under the condition of M3> 0 as described later (step 202).

If the polarity of the third axis yaw moment target value ΔM3 is negative, that is, ΔM3 <0, Δ
As will be described later, target air pressures P3Ld and P3Rd for the third shaft left brake cylinder 67 and the third shaft right brake cylinder 68 are calculated under the condition of M3 <0 (step 204).

(Target air pressure P3Ld under conditions that ΔM3> 0 (conditions for generating a clockwise yaw moment)
Processing to calculate P3Rd)
When the yaw moment is generated around the center of gravity G of the vehicle, in order not to decelerate the vehicle 100 unnecessarily, it is desirable that the braking force acting in the direction to cancel the yaw moment in the direction to be generated is zero. However, in reality, the brake force in the direction of cancellation cannot be made zero because it is necessary to apply pressure in the brake pipe to speed up the response, and the minimum value needs to be applied. . For this reason, the braking force acting in the direction to cancel the right yaw moment, that is, the braking force F3L acting on the third shaft left tire 25 is set to the minimum braking force F3Lmin (fixed value). Therefore, the yaw moment ΔM3 generated on the third axis 13 is given by the following equation.

ΔM3 = dR / F3R-dL / F3Lmin-(2)
Accordingly, the brake force F3R to be applied to the right tire 26 in order to generate the third axis yaw moment target value ΔM3 is given by the following equation.
F3R = (1 / dR) · (ΔM3 + dL · F3Lmin) (3)
There is a functional relationship F = f (P) between the air pressure P applied to the brake cylinders 65 to 68 and the brake force F acting on the corresponding tires 23 to 26. Here, for convenience of explanation, the function f is linearized,
F = S0 · P + Fe (4)
If so, the air pressure P is
P = (F−Fe) / S0 (5)
It is represented by However, S0 is an effective sectional area of the brake cylinders 65 to 68, and Fe is a constant.

Therefore, in order to generate the clockwise moment ΔM3, the left and right tires 25, 2 of the third shaft 13
Air pressures P3Ld and P3Rd to be applied to the brake cylinders 67 and 68 corresponding to 6 are given by the following equations.

The air pressure P3Rd to be applied to the brake cylinder 68 corresponding to the third axis right tire 26 is
Using Equation (3) and Equation (5),
P3Rd = (F3R−Fe) / S0
= (1 / S0 · dR) · (ΔM3 + dL · F3Lmin) −Fe / S0 (6)
It becomes.

The air pressure P3Ld to be applied to the brake cylinder 67 corresponding to the third axle left tire 25 is obtained by using a known brake force F3Lmin (fixed value), equation (5),
P3Ld = (F3Lmin−Fe) / S0 (7)
It becomes.

In this way, the target air pressures P3Ld and P3Rd to be applied to the third shaft left brake cylinder 67 and the third shaft right brake cylinder 68 under the condition of ΔM3> 0 are the above formulas (7) and (6), respectively.
Calculated as in the equation.

(Target air pressure P3Ld under the condition of ΔM3 <0 (condition for generating counterclockwise yaw moment),
Processing to calculate P3Rd)
As described above, the braking force acting in the direction to cancel the yaw moment in the left direction,
That is, the brake force F3R acting on the third shaft right tire 26 is set to the minimum brake force F3Rmin (fixed value). Accordingly, the yaw moment ΔM3 generated on the third axis 13 is given by the following equation.

ΔM3 = dR / F3Rmin-dL / F3L-(8)
Accordingly, the brake force F3L to be applied to the left tire 25 in order to generate the third axis yaw moment target value ΔM3 is given by the following equation.

F3L = (1 / dL) ・ (dR ・ F3Rmin−ΔM3) (9)
Therefore, in order to generate the counterclockwise moment ΔM3, the left and right tires 25, 2 on the third shaft 13
Air pressures P3Ld and P3Rd to be applied to the brake cylinders 67 and 68 corresponding to 6 are given by the following equations.

The air pressure P3Ld to be applied to the brake cylinder 67 corresponding to the third axis left tire 25 is
Using equation (9) and equation (5) above,
P3Ld = (F3L−Fe) / S0
= (1 / S0 · dL) · (dR · F3Rmin−ΔM3) −Fe / S0 (10)
It becomes.

The air pressure P3Rd to be applied to the brake cylinder 68 corresponding to the right tire 26 on the third axis is the known brake force F3Rmin (fixed value), using the above equation (5),
P3Rd = (F3Rmin−Fe) / S0 (11)
It becomes.

In this way, the target air pressures P3Ld and P3Rd to be applied to the third shaft left brake cylinder 67 and the third shaft right brake cylinder 68 under the condition of ΔM3 <0, respectively,
(11) Calculated according to the equation.

(Processing performed by the second axis brake air pressure calculation unit 52)
FIG. 15 is a view of the vehicle 100 as seen from above, like FIG. 5, FIG. 12, and FIG.
By applying braking force F2L and F2R to the left and right tires 23 and 24 respectively,
FIG. 6 is a diagram for explaining that a yaw moment ΔM2 is generated around the center of gravity G of the vehicle.

The distance from the center of gravity G of the vehicle to the center line of the left tire when going straight is dL,
If the distance from the center line of the right tire to the right tire during straight running is dR, the second shaft 12
The arm length of the yaw moment due to the braking force F2L acting on the left tire 23 is dL,
The arm length of the yaw moment due to the braking force F2R acting on the right tire 24 of the second shaft 12 when going straight is dR.

If the distance between the center of gravity G of the vehicle and the second shaft 12 is h, the arm of the yaw moment by the braking force F2R acting on the second shaft right tire 24 when the turning angle of the second shaft right tire 24 is δR. Length DR is
DR = dR · cosδR−hsinδR (12)
It becomes.

On the other hand, when the turning angle of the second axis left tire 23 is δL, the arm length DL of the yaw moment by the braking force F2L acting on the second axis left tire 23 is:
DL = dL · cos δL + hsin δL (13)
It becomes.

The steering wheel angle (steering angle) γ and the turning angles δL and δR of the second axle left and right tires 23 and 24 are expressed by the following equations using functions fL and fR that can be determined by the structure of the steering link mechanism.

δL = fL (γ) (14)
δR = fR (γ) (15)
From these equations (12), (13), (14) and (15),
DR = dR · cos (fR (γ)) − hsin (fR (γ)) (16)
DL = dL · cos (fL (γ)) + hsin (fL (γ)) (17)
Is obtained.

When the dimensions of the vehicle body 101 of the embodiment are applied to the above formula, the steering angle γ, the left and right tires 23,
FIG. 16 shows the relationship between the parameters DR / D0 and DL / D0 with the moment arm lengths DR and DL up to 24 based on the half D0 of the vehicle width W0 (= 1).

For example, if the steering wheel is turned to the right and the steering angle is set to a positive value γ, DR / D
= 0.80, DL / D0 = 1.15, and the arm of the yaw moment by the brake of the left tire 23 is larger than the brake of the right tire 24. In this example, when turning right at the steering angle γ, if the same braking force is applied to the left and right tires 23, 24, more of the momentum is generated by braking the left tire 23 than the right tire 24. Shows that a counterclockwise yaw moment is generated.

The yaw moment ΔM2 generated clockwise around the center of gravity G of the vehicle by the braking forces F2L and F2R acting on the second axle left tire 23 and the second axle right tire 24, respectively,
ΔM2 = DR.F2R-DL.F2L (18)
It becomes.

Therefore, if the polarity of the yamment ΔM2 in the equation (18) is positive, the vehicle 10
If a clockwise yaw moment is generated at 0 and the polarity of the yam moment ΔM2 in the equation (18) is negative, a counterclockwise yaw moment is generated in the vehicle 100.

Therefore, arithmetic processing may be performed according to the flowchart shown in FIG.

(Target air pressure P2Ld under the condition that ΔM2> 0 (a condition for generating a clockwise yaw moment),
Processing to calculate P2Rd)
In this case, as described above, the braking force acting in the direction to cancel the right yaw moment, that is, the braking force F2L acting on the second shaft left tire 23 is reduced to the minimum braking force.
F2Lmin (fixed value).

Accordingly, as described above, the air pressure P2Rd to be applied to the brake cylinder 66 corresponding to the right tire 24 of the second shaft 12 in order to generate the rightward yaw moment ΔM2 is:
It is given by the following formula.

P2Rd = (F2R-Fe) / S0
= (1 / S0 · DR) · (ΔM2 + DL · F2Lmin) −Fe / S0 (19)
On the other hand, the air pressure P2Ld to be applied to the brake cylinder 65 corresponding to the second shaft left tire 23
Is a known brake force F2Lmin (fixed value)
P2Ld = (F2Lmin−Fe) / S0 (20)
It becomes.

In this way, the target air pressures P2Ld and P2Rd to be applied to the second shaft left brake cylinder 65 and the second shaft right brake cylinder 66 under the condition of ΔM2> 0 are respectively expressed by the above equation (20),
It is calculated as shown in equation (19).

(Target air pressure P2Ld under the condition of ΔM2 <0 (condition for generating counterclockwise yaw moment),
Processing to calculate P2Rd)
In this case, as described above, the braking force acting in the direction of canceling the yaw moment in the left direction, that is, the braking force F2R acting on the second shaft right tire 24 is reduced to the minimum braking force.
F2Rmin (fixed value).

Therefore, as described above, the air pressure P2Ld to be applied to the brake cylinder 65 corresponding to the left tire 23 of the second shaft 12 in order to generate the leftward yaw moment ΔM2 is:
It is given by the following formula.

P2Ld = (F2L-Fe) / S0
= (1 / S0 · DL) · (DR · F2Rmin−ΔM2) −Fe / S0 (21)
On the other hand, the air pressure P2Rd to be applied to the brake cylinder 66 corresponding to the second shaft right tire 24
Is a known brake force F2Rmin (fixed value)
P2Rd = (F2Rmin−Fe) / S0 (22)
It becomes.

In this way, the target air pressures P2Ld and P2Rd to be applied to the second shaft left brake cylinder 65 and the second shaft right brake cylinder 66 under the condition of ΔM2 <0, respectively,
Calculated as shown in equation (22).

  FIG. 17 shows a flowchart of a processing procedure performed by the controller 30.

First, it is determined whether or not the driver is depressing the brake pedal 90 based on the detection signal Sb of the sensor 72 (step 301). As a result, the driver can use the brake pedal 90.
Is determined to be depressed, the exciting coils 69a of the automatic control valves 55 to 58,
The command signals ia, ib, ic for 69b, 69c are turned off, and the excitation coils 69a, 69 are turned off.
The excitation of b and 69c is stopped. As a result, the braking force Sb corresponding to the operation amount Sb of the brake pedal 90 acts on the tires 21 to 28 (step 307).

If it is determined in step 301 that the driver has not depressed the brake pedal 90, the selection unit 80 determines whether or not the third shaft 13 has been selected (step 302). When the third axis 13 is selected, the target value ΔMd of the yaw moment is mainly distributed to the third axis 13 using the above-described equations (33) and (34) (step 303).

Next, it is determined in the selection unit 80 whether or not the second axis 13 has been selected (step 304).

As a result, when it is determined by the selection unit 80 that neither the second axis 12 nor the third axis 13 is selected, the second axis 12, the third axis are calculated using the above-described equation (31). The yaw moments ΔM2 and ΔM3 to be distributed to 13 are set to zero.

When the selection unit 80 determines that only the second axis 12 is selected, the above-described (32)
The target value ΔMd of the yaw moment is distributed to the second axis 12 using the equation.

When the selection unit 80 selects the second axis 12 and the third axis 13 at the same time, the yaw moment ΔM2 to be distributed to the second axis 12 is set to zero according to the equation (34) or (35). Alternatively, the second shaft 12 can cover the shortage of the yaw moment generated by the third shaft 13 (step 305).

Next, the air of the brake cylinders 65, 66, 67, 68 of the second shaft 12 and the third shaft 13 is obtained so that the yaw moments ΔM2, ΔM3 distributed to the second shaft 12 and the third shaft in this way are obtained. The pressures P2L, P2R, P3L, and P3R are adjusted, and the yaw moment is controlled so that the yaw moment target value ΔMd is generated in the vehicle 100 (step 306).

In the above description, as illustrated in FIG. 5, the axle provided with the axles of the first shaft 11, the second shaft 12, the third shaft 12, and the fourth shaft 14 from the front to the rear of the vehicle 100. Number 1 vehicle 1
The description was given assuming 00. However, the present invention can be similarly applied to any vehicle 100 that has at least three axles and has at least one intermediate shaft excluding the frontmost axle and the rearmost axle.

FIG. 4 illustrates the vehicle 100 with three axles provided with the axles of the first shaft 11, the second shaft 12, and the third shaft 13 from the front to the rear of the vehicle 100. The vehicle 100 is the first
The shaft 11 and the second shaft 12 are configured as a steering shaft, and the third shaft 13 is configured as a non-steering shaft. In such a three-axis vehicle 100 as well, the yaw moment of the vehicle 100 is controlled by adjusting the braking force applied to the tires 23 and 24 of the second shaft 12 that is the intermediate shaft, as in the above-described embodiment. Can do.

Similarly, the present invention can be applied to a vehicle having five or more axles and a vehicle having three or more intermediate shafts.

FIG. 1 is a top view of a four-axis, eight-wheel vehicle, and is a diagram illustrating axles and wheels equivalent to a two-axis, four-wheel vehicle. FIGS. 2A, 2B, and 2C are diagrams for explaining the friction circle. FIG. 3 is a diagram for explaining the behavior of the vehicle when the lane is changed and the steering in a sudden and opposite direction is continuously performed while the vehicle is traveling at a high speed. FIG. 4 is a top view of a three-axis, six-wheel vehicle. FIG. 5 is a top view of a four-axis, eight-wheel vehicle. FIG. 6 is a block diagram of the vehicle drive system apparatus shown in FIG. FIG. 7 is a block diagram illustrating an apparatus configuration of a control system according to the embodiment. FIG. 8 is a block diagram showing a configuration example of the control system device shown in FIG. FIG. 9 is a block diagram of the vehicle brake system shown in FIG. FIGS. 10A and 10B are diagrams showing an example of the behavior of the vehicle when the control of the present invention is not performed. FIG. 11 is a top view showing each locus when the vehicle is turning right. FIG. 12 is a diagram comparing the yaw moments generated when the brakes are applied to the tires of the intermediate shafts when the vehicle turns right as shown in FIG. FIG. 13 is a top view of the vehicle and is a diagram for explaining that a yaw moment is generated around the center of gravity of the vehicle by applying a braking force to the left and right tires of the third axis. FIG. 14 is a flowchart illustrating a processing procedure performed by the third brake air pressure calculation unit and the second brake pressure calculation unit. FIG. 15 is a top view of the vehicle and is a diagram for explaining that a yaw moment is generated around the center of gravity of the vehicle by applying a braking force to the left and right tires of the second axis. FIG. 16 is a graph showing the relationship between the steering angle and the length of the moment arm up to the left and right tires. FIG. 17 is a flowchart showing a procedure of processing performed by the controller. FIG. 18 is a top view of a two-axis, four-wheel vehicle. FIG. 19A is a diagram for explaining a yaw moment generated when the rear wheel tire of the vehicle in FIG. 1 is braked. FIG. 19B is a diagram for braking the front wheel tire of the vehicle in FIG. It is a figure explaining the yaw moment generated in the case of.

Explanation of symbols

12 second axis (intermediate axis), 13 third axis (intermediate axis), 24, 25, 26, 27 tire (intermediate axis tire), 30 controller, 40 yaw angle controller, 50 yaw moment controller,
55-58 automatic control valve (intermediate shaft automatic control valve), 65-68 brake cylinder (intermediate shaft brake cylinder), 100 vehicle

Claims (4)

Yaw moment control means for controlling the yaw moment of the vehicle by adjusting the braking force applied to the tires of the intermediate shaft excluding the frontmost axle and the rearmost axle of the vehicle provided with three or more axles A yaw moment control device for a vehicle. From the front to the rear of the vehicle body, the first, second, and third axles are provided for a three-axle vehicle,
The vehicle yaw moment control device according to claim 1, wherein the yaw moment control means controls the yaw moment of the vehicle by adjusting a braking force applied to a tire of a second shaft that is an intermediate shaft. The first, second, third, and fourth axles provided from the front to the rear of the vehicle body are applied to a vehicle having four axles,
2. The vehicle according to claim 1, wherein the yaw moment control means controls the yaw moment of the vehicle by adjusting a braking force applied to a tire of the second axis and / or the third axis as an intermediate axis. Yaw moment control device. 2. The vehicle yaw moment control device according to claim 1, wherein when the intermediate shaft is a steered shaft, the braking force applied to the tire of the intermediate shaft is adjusted according to the steering angle.

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