WO2011052077A1

WO2011052077A1 - Vehicle motion control system

Info

Publication number: WO2011052077A1
Application number: PCT/JP2009/068707
Authority: WO
Inventors: 一平山崎
Original assignee: トヨタ自動車株式会社
Priority date: 2009-10-30
Filing date: 2009-10-30
Publication date: 2011-05-05

Abstract

Disclosed is a system for controlling the motion of a vehicle that has a single front wheel disposed at the front section of the vehicle, a left wheel and a right wheel disposed at the left and the right of the vehicle therebehind, and a single rear wheel disposed behind the left wheel and the right wheel. The system is granted the ability to alter the ratio (left-right wheel shared load ratio (R_W)) between the vehicle body load (front-back wheel shared load (W_FR)) shared by the front wheel and the back wheel, and the vehicle body load (left-right wheel shared load (W_LR)) shared by the left wheel and the right wheel. In a so-called vehicle having rhomboidally disposed wheels, by making the shared load ratio variable, vehicle movement characteristics corresponding to said change can be obtained.

Description

Vehicle motion control system

The present invention relates to a system for controlling the movement of a vehicle having a single front wheel disposed at the front portion of the vehicle and a left wheel and a right wheel disposed on the left and right of the vehicle behind the front wheel.

2. Description of the Related Art Conventionally, in a vehicle having a single front wheel and a left wheel and a right wheel provided behind the vehicle, there is a technique described in Patent Document 1 below as a system for controlling the movement of the vehicle. . The technology relates to the control of the turning motion of the vehicle, and more particularly to the control of the left wheel and the right wheel turning and the driving force difference accompanying the turning of the vehicle. In recent years, a vehicle as described in Patent Document 2 below, that is, a vehicle having a single rear wheel provided behind the left wheel and the right wheel in addition to the three wheels has been studied.

JP 2006-130985 A China authorized notice CN1304237C

Since the arrangement of wheels is different from that of a normal vehicle having two left and right front wheels and two right and left rear wheels, it is desirable to give special consideration to vehicle motion control. The motion control related to the vehicle as described above (hereinafter sometimes referred to as a “special wheel arrangement vehicle”) still has room for sufficient improvement. It is possible to improve. This invention is made | formed in view of such a situation, and makes it a subject to provide the vehicle motion control system for improving the practicality of a special wheel arrangement | positioning vehicle.

In order to solve the above-mentioned problems, a vehicle motion control system according to the present invention is a system for controlling the motion of the above-described special wheel-arranged vehicle having a rear wheel (hereinafter, sometimes referred to as “rhombic wheel-arranged vehicle”). The vehicle includes a shared load ratio changing device that changes a shared load ratio that is a ratio of a left and right wheel shared load to a front and rear wheel shared load of the vehicle body, and is configured to be able to control the load shared ratio.

In the vehicle with rhombus wheels, by making the share load ratio changeable, vehicle motion characteristics corresponding to the change can be obtained. Thereby, it is possible to make the motion of the vehicle appropriate in at least one of when going straight and turning.

Aspects of the Invention

Hereinafter, some aspects of the invention that is recognized as being capable of being claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is given a number, and is described in a form that cites other section numbers as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying the following sections, the description of the embodiments, etc., and as long as the interpretation is followed, other components are added to the aspects of the respective sections. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can also be an aspect of the claimable invention.

The combination of the following items (1) and (31) corresponds to claim 1, and the addition of the invention-specific matters described in claim (32) to claim 1 is claimed in claim 2. What added the invention specific matter of (33) to Claim 2 was added to Claim 3, and what added the invention specific matter of (34) to Claim 2 or Claim 3 was added to Claim 4. The invention specific matter described in (14) is added to any one of claims 1 to 4, and the invention specific matter described in (15) is added to claim 5. The invention-specific matters described in (11) and (12) are added to any one of claims 1 to 6 in claims 7 and 7, respectively. The invention-specific matters described in (17) are added to claims 8 and 8, and (14) and (15). To the claim 9 obtained by adding the subject matter according to term, an inventive specific matters according to (21) section to claim 9 to claim 10, corresponding respectively.

(1) A vehicle motion control system for controlling the motion of a vehicle having a single front wheel disposed in the front part of the vehicle and a left wheel and a right wheel disposed on the left and right of the front wheel behind the front wheel. Because
A front wheel steering device for steering the front wheels;
A left wheel driving braking device and a right wheel driving braking device for applying a driving braking force, which is a force for driving and braking the vehicle, to the left wheel and the right wheel, respectively;
A vehicle motion control system comprising: a control device that controls the vehicle.

The vehicle motion control system described in this section is a system in the most basic form, and is a premise of the system of the present invention. The vehicle targeted by the system of this aspect is the above-described special wheel arrangement vehicle, and the vehicle may be a three-wheeled vehicle having only the front wheel, the left wheel, and the right wheel, and further, the left wheel and the right wheel. It may be a vehicle having a single rear wheel disposed behind the vehicle (hereinafter sometimes referred to as a “rhombic wheel disposed vehicle”). The “front wheel steering device” in the system of this section may be a device configured to steer the front wheels by the driver's operation force applied to the steering operation member, and has a drive source to operate the steering. It may be configured to be mechanically separated from the member and to steer the front wheels by the force of the drive source while controlling the drive source in accordance with the operation of the steering operation member. It may be a so-called steer-by-wire type device. Note that various types of steering operation members such as a steering wheel, a joystick, and a lever can be adopted as the steering operation member.

“Drive / braking force” in this section is a concept for comprehensively or centrally handling the force for driving the wheel and the force for braking the wheel. Incidentally, the force for driving the wheel and the force for braking the wheel can be considered as the force for driving the vehicle and the force for braking the vehicle, respectively. Therefore, the “left wheel drive braking device” and “right wheel drive braking device” in this section include (a) a drive source such as an engine and a motor and a transmission mechanism for transmitting the force of the drive source as rotation of the wheel. And (b) a hydraulic brake device, an electric brake device, and a braking device such as a brake device (for example, a regenerative brake) that uses an electromotive force of the motor when the drive source is a motor. It can be considered as a constructed device. Note that the left wheel drive braking device and the right wheel drive braking device in the aspect of this section are not limited to those that can apply driving force to the left wheel and the right wheel independently of each other, as will be described later. On the other hand, it may be possible to apply a driving and braking force having a magnitude equal to or related to each other.

(2) The vehicle motion control according to (1), wherein the left wheel driving braking device and the right wheel driving braking device are configured to be able to apply driving force to the left wheel and the right wheel independently of each other. system.

This mode is a mode in which the left wheel drive braking device and the right wheel drive braking device are limited. These driving / braking devices include, for example, a driving device that has a dedicated driving source for each of the left wheel and the right wheel, and is configured so that the left wheel and the right wheel are driven independently. Is possible. In addition, the left and right wheels are braked independently, such as a brake-by-wire brake device, a brake device that uses an electromotive force of an electromagnetic motor provided as a dedicated drive source for each of the left and right wheels. It is possible to adopt a brake device.

(3) The vehicle motion control system is for controlling the motion of the vehicle further having a single rear wheel disposed behind the left wheel and the right wheel (1) or (2) The vehicle motion control system according to Item.

The vehicle motion control system according to the aspect of this section is a system in which the target vehicle is the above rhombus wheel arrangement vehicle. The target rear wheel of the vehicle may be a steered wheel that is steered or a non-steered wheel that is not steered. In the present specification, the “steered wheel” means a wheel that can be set to an arbitrary steered amount by an operation, control, or the like of a steering operation. For example, a wheel whose direction is freely changed like a caster is not a steered wheel but a non-steered wheel. Of course, the wheel whose direction is fixed is also a non-steered wheel.

(4) The vehicle motion control system according to (3), wherein the vehicle motion control system includes a rear wheel steering device that steers the rear wheel.

This mode is a mode in which the rear wheels are steered wheels. The “rear wheel steering device” in the system of this section is a device configured to steer the rear wheels by the driver's operation force applied to the steering operation member, like the front wheel steering device described above. Alternatively, a so-called steer-by-wire type device may be used.

(5) The vehicle motion control system is
It is a ratio of left and right wheel shared load that is a share of the left wheel and the right wheel to a front and rear wheel share load that is a share of the front wheel and the rear wheel of the weight of the vehicle body. The vehicle motion control system according to (3) or (4), comprising a shared load ratio changing device that changes the shared load ratio.

The specific configuration of the “shared load ratio changing device” in this section is not particularly limited. An apparatus having a configuration as will be described later is also possible. For example, one or more weights (weights) that can be moved are arranged on the vehicle body, and the one or more weights are moved in the front-rear direction. It is also possible to use an apparatus that changes the shared load ratio.

(6) The vehicle is configured such that the vehicle body is suspended by a plurality of suspension springs provided corresponding to the front wheel, the rear wheel, the left wheel, and the right wheel,
The shared load ratio changing device includes: (a) a vertical distance between the front wheel and the vehicle body and a vertical distance between the rear wheel and the vehicle body; and (b) a vertical distance between the left wheel and the vehicle body. The vehicle according to (5), configured to change the shared load ratio by generating a force in a direction to change at least one of a distance and a distance in a vertical direction between the right wheel and the vehicle body. Motion control system.

The aspect of this section is an aspect in which a limitation relating to the configuration of the shared load ratio changing device is added. Specifically, the shared load ratio changing device in this section treats the vehicle body as a rigid body, and increases or decreases the distance between the wheel and the vehicle body in the vertical direction (hereinafter sometimes referred to as “wheel vehicle body distance”). It is possible to change the shared load ratio by appropriately applying a force in a direction to be applied (hereinafter, referred to as “wheel vehicle body approaching / separating force”) between each of the four wheels and the vehicle body. . More specifically, for the front and rear wheels, a force is applied between the wheel and the body, and / or for the left and right wheels, the force is separated between the wheel and the body. By applying a force, it is possible to increase the left and right wheel sharing load with respect to the front and rear wheel sharing load. That is, the shared load ratio can be increased. Conversely, for the front wheel and the rear wheel, a force in a direction to separate them is applied between the wheel and the vehicle body, and / or for the left wheel and the right wheel, a force in a direction to make them approach between the wheel and the vehicle body. By acting, it is possible to reduce the left and right wheel sharing load with respect to the front and rear wheel sharing load. In other words, the shared load ratio can be reduced.

The structure for generating the wheel body approaching / separating force is not particularly limited. For example, between each of a plurality of suspension springs provided corresponding to four wheels and a portion of the vehicle body that supports the suspension springs, an actuator that changes the distance between them is arranged to increase the distance. Thus, it is possible to adopt a configuration in which the shared load of the corresponding wheel is reduced by increasing the shared load of the corresponding wheel and, conversely, by reducing the interval. Further, for example, four devices such as so-called electromagnetic dampers (electromagnetic shock absorbers) for applying a force between the wheel and the vehicle body are arranged corresponding to the four wheels, and each of the four devices is used. It is also possible to adopt a configuration in which the share load ratio is changed by applying a force between the corresponding wheel and the vehicle body at an appropriate ratio.

(11) The control device
The vehicle according to any one of (1) to (6), further including a front wheel turning amount control unit that controls the front wheel turning device to control a turning amount of the front wheel when the vehicle is turning. Vehicle motion control system.

The mode of this section is a mode in which the front wheel steering device is the steer-by-wire type steering device described above. If a steer-by-wire type steering device is adopted, for example, the amount of steering of the front wheels does not necessarily have to be controlled to a magnitude corresponding only to the amount of operation of the steering operation member. The amount of steering can be controlled according to various parameters such as speed and vehicle speed. That is, by employing a steer-by-wire type steering device, the degree of freedom in controlling the amount of steering can be made relatively high. The “steering amount” is an index representing the degree of steering of the wheel. For example, the turning angle of the wheel, that is, the turning phase angle with respect to the turning angle position of the wheel when going straight, It becomes a kind.

(12) The front wheel turning amount control unit determines a target lateral acceleration that is a lateral acceleration that should be generated in the vehicle during the turning of the vehicle based on an operation of a steering operation member, and is actually generated in the vehicle. The vehicle motion control system according to item (11), configured to control a turning amount of the front wheels so that an actual lateral acceleration that is a lateral acceleration approaches the target lateral acceleration.

The aspect of this section is an aspect in which a limitation on the front wheel steering method is added. Since the steering operation member is operated in accordance with the degree and state of the vehicle turning desired by the driver, the operation of the steering operation member becomes an intention display regarding the degree and state of the vehicle turning desired by the driver. On the other hand, the lateral acceleration generated in the vehicle at the time of turning can be considered as the lateral force acting on the vehicle divided by the vehicle weight, and an index indicating the degree and state of the turning (hereinafter referred to as “vehicle turning index”) There is a kind). In view of that, in the steering method of the aspect of this section, the amount of steering of the front wheels is not directly controlled based on the operation of the steering operation member, but based on the lateral acceleration that is a kind of vehicle turning index. Controlled. The steering method of the front wheels in the aspect of this section is a unique technique, and the vehicle motion control system of the aspect of this section in which the front wheels are steered by such a steering technique is based on the driver's intention. A suitable turning motion of the vehicle along the road will be realized.

For the control of the steering amount of the front wheels in the aspect of this section, for example, a feedback control method based on the deviation of the actual lateral acceleration with respect to the target lateral acceleration can be used. Specifically, it can be realized by control such as P control based on deviation, PI control, PID control. The method for determining the target lateral acceleration is not particularly limited. For example, a method described later, that is, a method of determining the size according to the operation amount of the steering operation member can be adopted, and for example, the operation speed of the steering operation member, the traveling speed of the vehicle A method based on various parameters such as “hereinafter referred to as“ vehicle speed ”in some cases) can be widely adopted.

Incidentally, the lateral force that is the basis for the occurrence of the lateral acceleration is a force acting on the vehicle at the wheel. Therefore, when the lateral force acts on the vehicle, the inertia force in the opposite direction acts on the vehicle body. In view of this, when detecting the actual lateral acceleration, a lateral acceleration sensor provided on the vehicle body may be used to detect the actual lateral acceleration based on the detected value.

(13) The vehicle motion control system according to (12), wherein the front wheel turning amount control unit is configured to determine the target lateral acceleration to a size according to an operation amount of the steering operation member.

The mode in this section is a mode in which a limitation on the method for determining the target lateral acceleration is added. According to the aspect of this section, the vehicle turning motion as desired by the driver is appropriately realized. By the way, according to the determination method of this aspect, even when the operation amount of the steering operation member is the same, the front wheel turning amount is generally small when the vehicle speed is high, and the front wheel turning amount is low when the vehicle speed is low. Becomes bigger.

(14) The left wheel driving braking device and the right wheel driving braking device are configured to be able to apply the driving braking force to the left wheel and the right wheel independently of each other,
The control device is
When the vehicle turns, the left wheel drive braking device and the right wheel drive braking device are controlled to control a left and right wheel drive braking force difference that is a difference between the left wheel drive braking force and the right wheel drive braking force. The vehicle motion control system according to any one of items (1) to (14), further including a left / right wheel drive braking force difference control unit.

The aspect of this section is an aspect configured to control the movement of the vehicle by making a difference between the driving force of the left wheel and the driving force of the right wheel. For example, by making a difference between the driving and braking force of the left wheel and the right wheel that are turning outer wheels (wheels farther from the turning center) and the driving force of the turning inner wheel (wheels closer to the turning center) Can also change the orientation of the vehicle. For example, the yaw rate of the vehicle during vehicle turning can be controlled by the difference in driving force. In view of this, the aspect of this section is an aspect in which the turning motion of the vehicle is controlled by controlling the driving / braking force difference. According to the aspect of this section, it is possible to realize a vehicle turning motion with good characteristics. In addition, the aspect of this term is combined with the aspect regarding the front wheel turning amount control unit described above, thereby realizing a vehicle turning motion with better characteristics. Incidentally, the “driving braking force difference” may be a difference in driving force between the left and right wheels by the above-described driving device, or may be a difference in braking force between the left and right wheels by the above-described braking device. In other words, when the vehicle is accelerating or when the vehicle speed is maintained, the difference is mainly the driving force, and when the vehicle is decelerating, the difference is mainly the braking force.

(15) The left and right wheel driving braking force difference control unit determines a target yaw rate that is a yaw rate to be realized in turning of the vehicle based on an operation of a steering operation member, and uses a yaw rate actually generated in the vehicle. The vehicle motion control system according to item (14), configured to control the left and right wheel drive braking force difference so that a certain actual yaw rate approaches the target yaw rate.

The aspect of this section is an aspect in which a limitation relating to the control method of the driving / braking force difference is added. As described above, the operation of the steering operation member serves as an intention display regarding the degree and state of the vehicle turning desired by the driver. On the other hand, the yaw rate of the vehicle at the time of vehicle turning is also a kind of vehicle turning index described above. In view of this, in the aspect of this section, the driving / braking force difference is not directly controlled based on the operation of the steering operation member, but is controlled based on the yaw rate, which is a kind of vehicle turning index. The control method of the driving / braking force difference in the aspect of this section is a unique technique, and according to the vehicle motion control system of the aspect of this section in which the driving / braking force difference is controlled by such a control method, the driver's An appropriate vehicle turn according to the intention is realized.

The control of the driving / braking force difference in the aspect of this section can use, for example, a feedback control method based on the deviation of the actual yaw rate with respect to the target yaw rate, similarly to the control of the front wheel turning amount described above. is there. Specifically, it can be realized by control such as P control based on deviation, PI control, PID control. Incidentally, the actual yaw rate can be detected by using a yaw rate sensor provided on the vehicle body. The method for determining the target yaw rate is not particularly limited. For example, a method described later, that is, a method of determining a size corresponding to the operation amount of the steering operation member divided by the vehicle speed can be adopted, and for example, the operation of the steering operation member can be adopted. A method based on various parameters such as the amount, the operation speed of the steering operation member, and the vehicle speed can be widely adopted.

Also, it is desirable to combine the aspect of this section with the control of the front wheel turning amount based on the lateral acceleration described above. By combining the front wheel turning amount based on the lateral acceleration and the driving force difference between the left and right wheels based on the yaw rate, the followability to the change in the target lateral acceleration (responsiveness to the lateral acceleration), the followability to the change in the target yaw rate ( Both responsiveness with respect to yaw rate are good. That is, it is considered that one of these two controls functions to assist the other control. Incidentally, the effect of the combination of the two controls is higher when the vehicle speed is high than when the vehicle speed is low. In this sense, it is particularly desirable to execute the combination of the two controls at least when the vehicle speed is high.

(16) The left and right wheel drive braking force difference control unit is configured to determine the target yaw rate to a size according to the operation amount of the steering operation member divided by the traveling speed of the vehicle ( The vehicle motion control system according to item 15).

The aspect of this section is an aspect in which a limitation relating to the target yaw rate determination method is added. According to the aspect of this section, the vehicle turning as desired by the driver is appropriately realized. By the way, according to the determination method of this aspect, even when the operation amount of the steering operation member is the same, the vehicle yaw rate generally increases when the vehicle speed is high, and the vehicle yaw rate decreases when the vehicle speed is low. .

(17) The vehicle motion control system is
The vehicle further has a single rear wheel disposed behind the left wheel and the right wheel, and controls the movement of the vehicle, and includes a rear wheel steering device that steers the rear wheel,
The control device is
The vehicle according to any one of (11) to (16), further including a rear wheel turning amount control unit that controls a rear wheel turning device to control a turning amount of the rear wheel when the vehicle turns. Vehicle motion control system.

The aspect of this section is an aspect in which the rear-wheel steering device is the steer-by-wire type steering device described above when the vehicle to be subjected to motion control is the rhombus-wheel-arranged vehicle. If a steer-by-wire type steering device is used to control the steering of the rear wheels, for example, the turning characteristics of the vehicle with rhombus wheels can be improved. As in the case of the front wheels, the amount of steering of the rear wheels does not necessarily have to be controlled to a magnitude corresponding to the amount of operation of the steering operation member, and the degree of freedom in controlling the amount of steering is relatively high. Is possible.

Regarding the steering direction of the rear wheels relative to the steering direction of the front wheels, if they are in the same direction, it is said that the rear wheels are steered in phase with the front wheels, and if they are in opposite directions, the rear Let's say that the wheels are steered in the opposite phase to the front wheels. According to such a way of speaking, in the aspect of this section, the rear wheel may be steered in the same phase with respect to the front wheel, or may be steered in the opposite phase. For example, it is possible to control the rear wheel steering so that it is determined in accordance with the vehicle speed. More specifically, when the vehicle speed is high, the rear wheels are steered in phase with respect to the front wheels in consideration of the running stability of the vehicle, and when the vehicle speed is low, the turning performance of the vehicle (vehicle In view of, for example, improvement in performance regarding ease of changing the direction, it is possible to perform control such that the rear wheels are steered in the opposite phase to the front wheels. By the way, when the rear wheels are steered in phase with the front wheels, the vehicle performs a turning motion with a relatively large lateral acceleration and a relatively small yaw rate. When the vehicle is steered in the opposite phase, the vehicle performs a turning motion in which the lateral acceleration generated in the vehicle is relatively small and the yaw rate is relatively large.

(18) The control device
A front wheel turning amount control unit that controls the front wheel turning device to control the turning amount of the front wheel during turning of the vehicle;
The front wheel turning amount control unit determines a target lateral acceleration that is a lateral acceleration that should be generated in the vehicle during the turning of the vehicle based on the operation of the steering operation member, and the lateral acceleration actually generated in the vehicle is determined. It is configured to control the amount of steering of the front wheels so that a certain actual lateral acceleration approaches the target lateral acceleration,
The rear wheel turning amount control unit controls the rear wheel turning device so that the approach to the target lateral acceleration of the actual lateral acceleration realized by the control by the front wheel turning amount control unit is assisted. The vehicle motion control system according to item (17), which is configured to control a turning amount of the rear wheel.

The aspect of this section is an aspect in which the method of controlling the rear wheel turning amount is specifically limited when the control of the front wheel turning amount based on the lateral acceleration described above is adopted. According to the aspect of this section, it is possible to improve the followability to the change in the target lateral acceleration described above.

(19) The left wheel driving braking device and the right wheel driving braking device are configured to be able to apply the driving braking force to the left wheel and the right wheel independently of each other,
The control device is
Left and right wheel drive braking force difference control that controls the difference between the left wheel drive braking force and the right wheel drive braking force by controlling the left wheel drive braking device and the right wheel drive braking device when the vehicle is turning. Part
The left and right wheel drive braking force difference control unit determines a target yaw rate that is a yaw rate to be realized in turning of the vehicle based on the operation of the steering operation member, and an actual yaw rate that is actually generated in the vehicle Is configured to control the difference between the driving force of the left wheel and the driving force of the right wheel so as to approach the target yaw rate,
The rear wheel turning amount control unit controls the rear wheel turning amount so that the approach of the actual yaw rate to the target yaw rate, which is realized by the control by the left and right wheel drive braking force difference control unit, is assisted. The vehicle motion control system according to item (17), configured to

The aspect of this section is an aspect in which the control method of the rear wheel turning amount is specifically limited when the control of the difference in driving force between the left and right wheels based on the yaw rate described above is employed. According to the aspect of this section, it is possible to improve the followability to the change of the target yaw rate described above.

(20) The control device
A front wheel turning amount control unit that controls the front wheel turning device to control the turning amount of the front wheel during turning of the vehicle;
The front wheel turning amount control unit determines a target lateral acceleration that is a lateral acceleration that should be generated in the vehicle during the turning of the vehicle based on the operation of the steering operation member, and the lateral acceleration actually generated in the vehicle is determined. It is configured to control the amount of steering of the front wheels so that a certain actual lateral acceleration approaches the target lateral acceleration,
The left wheel driving braking device and the right wheel driving braking device are configured to be able to apply the driving braking force to the left wheel and the right wheel independently of each other,
The control device is
When the vehicle turns, the left wheel drive braking device and the right wheel drive braking device are controlled to control a left and right wheel drive braking force difference that is a difference between the left wheel drive braking force and the right wheel drive braking force. The left and right wheel drive braking force difference control unit
The left and right wheel drive braking force difference control unit determines a target yaw rate that is a yaw rate to be realized in turning of the vehicle based on the operation of the steering operation member, and is an actual yaw rate generated in the vehicle. The vehicle motion control system according to item (17), configured to control the left and right wheel drive braking force difference so that a yaw rate approaches the target yaw rate.

The aspect of this section is an aspect that employs both the control of the front wheel turning amount based on the lateral acceleration described above and the control of the driving force difference between the left and right wheels based on the yaw rate.

(21) The rear wheel turning amount control unit approaches the target lateral acceleration of the actual lateral acceleration realized by the control by the front wheel turning amount control unit, and is controlled by the left and right wheel driving braking force difference control unit. The vehicle motion control according to (20), wherein the steering amount of the rear wheel is controlled so that at least one of the actual yaw rate and the approach to the target yaw rate is assisted by system.

In the aspect of this section, when both the control of the front wheel turning amount based on the lateral acceleration described above and the control of the driving / braking force difference between the left and right wheels based on the yaw rate are adopted, the control of the rear wheel turning amount is controlled. This is a mode in which the method is specifically limited. According to the aspect of this section, it is possible to improve at least one of the followability to the change in the target lateral acceleration and the followability to the change in the target yaw rate described above. In addition, by controlling the turning amount of the rear wheel so as to assist both the approach of the actual lateral acceleration to the target lateral acceleration and the approach of the actual yaw rate to the target yaw rate, It is possible to improve both the following ability to change and the following ability to change the target yaw rate.

(22) The rear wheel turning amount control unit determines the turning amount of the rear wheel when the actual lateral acceleration is smaller than the target lateral acceleration and the actual yaw rate is larger than the target yaw rate. When the actual lateral acceleration is larger than the target lateral acceleration and the actual yaw rate is smaller than the target yaw rate, the rear wheel is opposite to the front wheel. The vehicle motion control system according to item (20) or (21), wherein the vehicle motion control system is configured to control the vehicle to steer in the direction of.

The aspect of this section is considered as a kind of aspect in which the turning amount of the rear wheel is controlled so as to assist both the approach of the actual lateral acceleration to the target lateral acceleration and the approach of the actual yaw rate to the target yaw rate. be able to. According to the aspect of this section, it is possible to improve both the followability to the change in the target lateral acceleration and the followability to the change in the target yaw rate.

(23) The rear wheel turning amount control unit determines a target revolution centripetal acceleration that is a revolution centripetal acceleration that should occur in the vehicle when the vehicle turns, and is an actual revolution centripetal acceleration actually occurring in the vehicle. The vehicle motion control system according to any one of (17) to (22), wherein the turning amount of the rear wheel is controlled so that the revolution centripetal acceleration approaches the target revolution centripetal acceleration. .

The lateral acceleration is the lateral acceleration in the coordinate system centered on the vehicle, and the “revolution centripetal acceleration” can be considered as the lateral acceleration in the road surface coordinate system. In other words, it can be considered that the product of the vehicle speed and the yaw rate is subtracted from the lateral acceleration. The mode of this section is a mode of controlling the rear wheel turning amount based on this revolution acceleration. Generally speaking, the aspect of this section is an aspect of controlling the rear wheel turning amount so as to assist both the approach of the actual lateral acceleration to the target lateral acceleration and the approach of the actual yaw rate to the target yaw rate. Can be thought of as a kind of According to the aspect of this section, it is possible to improve both the followability to the change in the target lateral acceleration and the followability to the change in the target yaw rate.

The control of the rear wheel turning amount in the aspect of this section is, for example, the deviation of the actual revolution centripetal acceleration with respect to the target revolution centripetal acceleration, similarly to the control of the front wheel turning amount and the control of the driving force difference between the left and right wheels. It can be realized by the method of feedback control based on. Specifically, it can be realized by control such as P control based on deviation, PI control, PID control. Incidentally, the actual lateral acceleration and the actual yaw rate can be detected by using the lateral acceleration sensor and the yaw rate sensor provided on the vehicle body as described above. Further, the target revolution centripetal acceleration is determined based on, for example, when the target lateral acceleration is determined in the control of the front wheel turning amount and the target yaw rate is determined in the control of the driving force difference between the left and right wheels. That's fine. The deviation of the actual revolution centripetal acceleration with respect to the target revolution centripetal acceleration is the deviation of the actual lateral acceleration with respect to the target lateral acceleration in the control of the front wheel turning amount, and the actual yaw rate with respect to the target yaw rate in the control of the driving force difference between the left and right wheels. May be determined by subtracting the product of the latter and the vehicle speed from the former.

(31) The vehicle motion control system controls the motion of the vehicle further having a single rear wheel disposed behind the left wheel and the right wheel, and the weight of the vehicle body of the vehicle The load sharing ratio, which is the ratio of the left and right wheel shared load that is shared by the left wheel and the right wheel, to the front and rear wheel shared load that is shared by the front wheel and the rear wheel is changed. Equipped with a shared load ratio change device,
The control device is
The vehicle motion control system according to any one of (1) to (20), further including a shared load ratio change control unit that controls the shared load ratio by controlling the shared load ratio changing device.

The mode of this section is a mode for performing control for the motion of the rhombus wheel arrangement vehicle described above. By changing the shared load ratio, vehicle motion characteristics corresponding to the shared load ratio can be obtained. Specifically, for example, by reducing the left and right wheel shared load relative to the front and rear wheel shared load, that is, by reducing the shared load ratio, it is possible to improve the straight running stability of the rhombus wheel arrangement vehicle, Conversely, by reducing the left and right wheel shared load with respect to the front and rear wheel shared load, that is, by increasing the shared load ratio, it becomes possible to improve the driving performance of the rhombus wheel arrangement vehicle. Incidentally, the drive performance here means performance related to the magnitude of the propulsive force of the vehicle obtained by the rotation of the left and right wheels, which are drive wheels.

運動 As a general rule, it is possible to think about the movement during turning as follows. For example, considering a turn performed by turning the rear wheels in phase with respect to the front wheels, during such a turn, the left and right wheels are greatly resistant to the lateral translation of the vehicle. In other words, the frictional force between the left and right wheels and the road surface due to the lateral motion component of the vehicle (which can also be considered as a lateral force generated by the left and right wheels) acts to reduce the lateral acceleration during turning. Therefore, by reducing the shared load ratio, it is possible to reduce the ground load on the left and right wheels, and to make the vehicle with rhombus wheels easily perform a turning motion that requires a relatively large lateral acceleration. On the other hand, for example, when considering a case where the vehicle is turning by positively using the left and right wheel drive braking force difference, the front and rear wheels are resistant to the turning motion of the vehicle. That is, the frictional force between the front and rear wheels and the road surface in the yaw motion of the vehicle (which can be considered as a lateral force generated by the left and right wheels) acts so that the yaw rate of the vehicle is reduced. Therefore, by increasing the share load ratio, the ground contact load of the front and rear wheels can be reduced, and the vehicle with the rhombus wheels can be easily turned so that a relatively large yaw rate is required.

(32) The vehicle motion control system according to (31), wherein the shared load ratio change control unit is configured to control the shared load ratio based on a traveling speed of the vehicle.

According to the aspect of this section, for example, the shared load ratio can be changed according to the vehicle speed. In general, the vehicle motion characteristics required for a vehicle with rhombus wheels change depending on the vehicle speed. According to the aspect of this section, it is possible to realize a rhombus wheel-arranged vehicle that can meet such a demand.

(33) The shared load ratio change control unit is configured to control the shared load ratio change device so that the shared load ratio is smaller when the traveling speed of the vehicle is high than when the vehicle is low. The vehicle motion control system according to item (32).

As described above, in general, when the vehicle speed is high, a vehicle with a rhombus wheel has a relatively large lateral acceleration generated in the vehicle and a relatively small yaw rate of the vehicle in view of the running stability of the vehicle. It is desirable to be controlled to perform a swivel motion. Conversely, when the vehicle speed is low, it is desirable to control the vehicle so as to perform a turning motion in which the lateral acceleration generated in the vehicle is relatively large and the vehicle yaw rate is relatively small in view of improvement in the turning performance of the vehicle. According to the aspect of this section, for the reason described above, when the vehicle speed is high, it is possible to easily cause the vehicle with rhombus wheels to perform a turning motion that requires a relatively large lateral acceleration. On the other hand, when the vehicle speed is low, it is possible to easily cause the vehicle with rhombus wheels to perform a turning motion that requires a relatively large yaw rate.

In addition, when changing a shared load ratio according to a vehicle speed, it is also possible to change continuously and to change in steps. Extremely speaking, an aspect in which the shared load ratio when the vehicle speed is higher than the threshold is smaller than the shared load ratio when the vehicle speed is lower than the threshold across a certain threshold regarding the vehicle speed is also the aspect of this section It is included in.

(34) The shared load ratio change control unit is configured such that when the vehicle traveling speed is higher than a set threshold speed, the front and rear wheel shared load is larger than the left and right wheel shared load, and the vehicle traveling speed is (32) or (33), wherein the shared load ratio changing device is configured to control the front and rear wheel shared load to be smaller than the left and right wheel shared load when lower than the set threshold speed. Vehicle motion control system.

The aspect of this section is an aspect in which a limitation relating to the magnitude relationship between the front and rear wheel shared load and the left and right wheel shared load is added. The aspect of this section can also be considered as one aspect of the aspect of controlling so as to reduce the shared load ratio when the vehicle speed is high compared to when the vehicle speed is low.

It is a schematic side view of the vehicle carrying the vehicle motion control system which is an Example of claimable invention. It is a conceptual diagram which shows the whole structure of the vehicle shown in FIG. 1, and the vehicle motion control system mounted in the vehicle. It is sectional drawing which shows the left wheel (right wheel) of the vehicle shown in FIG. 1, and the suspension apparatus, drive device, and braking device which were provided with respect to it. It is a figure which shows the front wheel (rear wheel) of the vehicle shown in FIG. 1, and the steering apparatus provided with respect to it. It is a figure which shows notionally the mode of steering of the front wheel and rear wheel by turning control, and the right-and-left wheel drive braking force difference. FIG. 6 is a graph for comparing and explaining changes in lateral acceleration and yaw rate that occur in a vehicle during turning in a case of turning under turning control and in a case of turning only by turning front wheels. FIG. FIG. 5 is a graph for comparing and explaining changes in lateral acceleration and yaw rate when a lane change is performed in a case of turning under control during turning and in a case of turning only by turning front wheels. It is a graph which shows the change of the ratio of the shared load of the right-and-left wheel with respect to the shared load of the front and rear wheel by shared load ratio change control. It is a figure which shows notionally the mode that the load of a vehicle body is shared by the front-and-rear wheel and a left-right wheel. It is a conceptual diagram for demonstrating the motion of the vehicle at the time of a turn in the case of changing a shared load ratio. It is a graph which shows the effect by the change of the shared load ratio at the time of performing a lane change at high speed. It is a graph which shows the effect by the change of the shared load ratio at the time of performing lane change at low speed. It is a flowchart of the vehicle motion control program performed in a vehicle motion control system. It is a flowchart of the turning control subroutine which comprises a vehicle motion control program. It is a flowchart of the front-wheel steering amount control subroutine which comprises a turning control subroutine. It is a flowchart of the left and right wheel drive braking force difference control subroutine constituting the turning control subroutine. It is a flowchart of the rear-wheel steering amount control subroutine which comprises a turning control subroutine. It is a flowchart of the acceleration / deceleration control subroutine which comprises a vehicle motion control program. It is a flowchart of the shared load ratio change control subroutine which comprises a vehicle motion control program. It is a block diagram which shows the function part of the electronic control unit mounted in the vehicle as a control apparatus of a vehicle motion control system.

Hereinafter, a representative embodiment of the claimable invention will be described in detail with reference to the drawings as an example. In addition to the following examples, the claimable invention is implemented in various modes including various modifications and improvements based on the knowledge of those skilled in the art, including the mode described in the above [Mode of Invention]. can do.

≪Vehicle configuration≫
FIG. 1 shows a vehicle equipped with the vehicle motion control system of the embodiment. This vehicle is a vehicle with rhombus wheels, and is expected as a next generation commuter. The vehicle includes a vehicle body 10, a front wheel 12F provided at a front portion thereof, a left wheel 14L and a right wheel 14R provided respectively at a left portion and a right portion of the vehicle body 10 behind the front wheel 12F, and the left wheel 14L. , And a rear wheel 12R provided behind the right wheel 14R. As can be seen from FIG. 2 showing a plan view of the vehicle, the front wheel 12F and the rear wheel 12R are disposed at the center in the vehicle width direction. In the following description, when it is not necessary to distinguish between the front wheel 12F and the rear wheel 12R, it is collectively referred to as the wheel 12, and when it is not necessary to distinguish between the left wheel 14L and the right wheel 14R, it is collectively referred to as the wheel 14. To do. The same applies to the components, parameters, and the like related to the front wheel 12F, the rear wheel 12R, the left wheel 14L, and the right wheel 14R.

In this vehicle, as will be described in detail later, the front wheel 12F and the rear wheel 12R are steered wheels, and the left wheel 14L and the right wheel 14R are not steered wheels. Although the left wheel 14L and the right wheel 14R are driving wheels (wheels that are rotationally driven to drive the vehicle), the front wheels 12F and the rear wheels 12R are not driving wheels. Similarly, although the left wheel 14L and the right wheel 14R are used as braking wheels (wheels whose rotation is braked to brake the vehicle), the front wheels 12F and the rear wheels 12R are not used as braking wheels.

This vehicle is provided with three operation members as operation members for the driver to operate the vehicle. One of them is a steering wheel 20 that is a steering operation member for causing the vehicle to perform a turning operation, the other is an accelerator pedal 22 that is an accelerator operation member for accelerating the vehicle, and the other is an operation of the vehicle. It is the brake pedal 24 which is a brake operation member for decelerating. Incidentally, this vehicle can be moved not only forward but also backward, but in the following description, only forward is described in order to avoid redundancy of the present specification.

If the left wheel 14L and the right wheel 14R are described, the wheel 14 includes a wheel body 30 and a tire 32, as can be seen from FIG. The wheel body 30 is fixed to an axle 34, and the axle 34 is rotatably held by a carrier 36. The carrier 36 is swingable with respect to the vehicle body by a lower arm 38 and an upper arm 40 that are suspension arms constituting the suspension device. A lower end portion of a hydraulic shock absorber 42 is attached to the lower arm 38. The upper end of the shock absorber 42 is supported on the vehicle body via a spring support position adjusting device 44. The spring support position adjusting device 44 is for increasing or decreasing the distance in the vertical direction between the upper end portion of the shock absorber 42 and the support portion of the vehicle body, and includes an electromagnetic motor. By controlling the operation of the motor, it is possible to adjust the support position (hereinafter also referred to as “spring support position”) of the upper end portion of the suspension spring 46, which will be described later, with respect to the vehicle body.

The hydraulic shock absorber 42 has a lower tube 48 and an upper tube 50, and can be expanded and contracted by being relatively movable. A lower retainer 52 is fixed to the lower tube 48, and an upper retainer 54 is fixed to the upper tube 50, and the suspension spring 46 is sandwiched between the lower retainer 52 and the upper retainer 54. With such a configuration, the wheel 14 is rotatable and elastically swingable up and down.

The carrier 36 has a short cylindrical coil holding portion 58 outside the hub portion 56 that holds the axle 34. A plurality of coils 60 constituting an electromagnetic motor are provided on the outer periphery of the coil holding portion 58. Is retained. On the other hand, a plurality of magnets 62 are disposed on the rim portion of the wheel body 30 along the inner peripheral surface thereof. The plurality of coils 60 and the plurality of magnets 62 face each other, and they constitute a brushless DC motor. That is, the wheel 14 is rotationally driven by an in-wheel motor charged inside the wheel body 30, and the in-wheel motor functions as a driving device 64 in the vehicle. Although not described in detail, the in-wheel motor also functions as a generator by the rotation of the wheel 14. The drive device 64 is configured to function also as a regenerative brake device by regenerating the current generated by the electromotive force of the motor.

Also, a brake disc 66 is fixed to the axle 34. On the other hand, a caliper device 68 that holds a brake pad is fixed to the carrier 36. The caliper device 68 is configured to press the brake pad against the brake disc 66 by the force of the electromagnetic motor. That is, the vehicle has a disc-type braking device 70 constituted by the brake disc 66 and the caliper device 68.

Next, the front wheel 12F and the rear wheel 12R will be described. As can be seen from FIG. 4, the wheel 12 includes a wheel body 80 and a tire 82. The wheel body 80 is sandwiched from the left and right by a pair of hydraulic shock absorbers 84. More specifically, the axle 88 provided on the hub portion 86 of the wheel main body 80 is rotatably held by the bearing portion 90 provided at the lower end of each of the pair of shock absorbers 84, so that the wheel 12. Is made rotatable.

Each upper end portion of the pair of shock absorbers 84 is fixed to a support plate 92 extending in the vehicle width direction, and the support plate 92 connects the upper end portions of the pair of shock absorbers 84. A shaft 94 is fixedly attached to the support plate 92, and the shaft 94 is rotatably held by a bearing portion 96 provided on the vehicle body. The shaft 94 extends upward from the bearing portion 96, and the wheel 12 is steered when the steered device 98 rotates the extended portion. The steering device 98 includes an electromagnetic motor, and is configured to steer the wheel 12 at an arbitrary turning angle by controlling the operation of the electromagnetic motor. The steering device 98 has a stopper for preventing the wheels 12 from being steered by 90 ° or more on both the left and right sides.

Each of the pair of shock absorbers 84 includes a lower tube 100 and an upper tube 102, and they can be expanded and contracted by being relatively movable. A lower retainer 104 is fixed to the lower tube 100, and each of the pair of suspension springs 108 is sandwiched between the lower retainer 104 of each of the pair of shock absorbers 84 and the support plate 92. With such a configuration, the wheel 12 is elastically swingable up and down.

≪Configuration of vehicle motion control system≫
The movement of the vehicle is controlled by a vehicle movement control system whose overall configuration is shown in FIG. This system includes an electronic control unit (hereinafter abbreviated as “ECU”) 130 as a control device that forms the core of the system. The ECU 130 is a computer-based device, such as a left wheel drive device [D _L ] 64L, a right wheel drive device [D _R ] 64R, a left wheel brake device [B _L ] 70L, and a right wheel brake device [B _R ]. 70R, left wheel spring support position adjustment device [H _L ] 44L, right wheel spring support position adjustment device [H _R ] 44R, front wheel steering device [S _F ] 98F, rear wheel steering device [S _R ] 98R Thus, the movement of the vehicle is controlled. Incidentally, the ECU 130 also has a driver circuit for controlling the operation of the electromagnetic motors of these devices.

In addition, this vehicle movement system is provided with various sensors as a device which acquires the parameter for control. Specifically, a vehicle speed sensor [v] 132 for detecting the traveling speed (vehicle speed) v of the vehicle, a steering sensor [θ] 134 for detecting the operation angle θ of the steering wheel 20, and the operation amount of the accelerator pedal 22 horizontal for detecting a _O accelerator sensor for detecting [a _O] 136, a brake sensor [b _O] 138 for detecting an operation amount b _O of the brake pedal 24, the lateral acceleration Gy caused in the vehicle body Acceleration sensor [Gy] 140, yaw rate sensor [γ] 142 for detecting the yaw rate γ of the vehicle, left wheel spring support position sensor for detecting the spring support positions h _L and h _R on the left wheel side and the right wheel side, respectively. [h _L] 144L and a right wheel spring support position sensor [h _R] 144R, the front wheel steering angle sensor for detecting the front wheel turning angle [delta] _F is the steering amount of the front wheel [[delta] _F] 1 6F, the rear wheel wheel steering angle sensor [[delta] _R] 146R after for detecting wheel steering angle [delta] _R after a steering amount of are provided on the vehicle body, their sensors are linked to ECU130 . The lateral acceleration sensor [Gy] is for detecting the lateral acceleration Gy actually generated in the vehicle body. However, the lateral acceleration Gy actually generated in the vehicle is the lateral acceleration Gy in the opposite direction. In the control of the vehicle motion system, the lateral acceleration Gy generated in the vehicle body is treated as the lateral acceleration Gy actually generated in the vehicle to control the vehicle motion.

≪Vehicle motion control≫
a) Acceleration / deceleration control Among the motion control of the vehicle, acceleration / deceleration control which is control for accelerating the vehicle and control for decelerating the vehicle is performed as follows. When the vehicle is accelerated, the accelerator pedal 22 is operated by the driver. Therefore, the vehicle is given to the vehicle according to the following expression (1) based on the operation amount a _O of the accelerator pedal 22 detected by the accelerator sensor 136. driving force F _D to, i.e., the driving force F _D applied left and

right wheels

14L, 14R and is determined. K _D is a driving force gain for determining the driving force F _D.
F _D = K _D · a _O (1)
On the other hand, when decelerating the vehicle, the brake pedal 24 is operated by a driver, based on the operation amount b _O of the brake pedal 24 detected by the brake sensor 138, according to the following equation (2), the vehicle braking force F _B to be applied to, i.e., left and right wheels 14L, the braking force F _B applied to 14R are determined. K _B is the braking force gain for determining the braking force F _B.
F _B = K _B · b _O (2)
The driving force gain K _D and the braking force gain K _B may be constants or may be changed based on some parameter.

In the acceleration / deceleration control, the driving force F _D and the braking force F _B are handled in a unified manner, so the driving braking force F is determined according to the following equation (3).
F = F _D -F _B (3)
That is, when F> 0, the driving force F is applied to the vehicle, and when F <0, the braking force F is applied to the vehicle. Then, the left wheel and the driving braking force F, so as to share the right wheel, the following equation (4), according to (5), Hidariwaka braking force F _L, Migiwaka braking force F _R is determined.
F _L = F / 2 (4)
F _R = F / 2 (5)

The left wheel driving braking force F _L, based on Migiwaka braking force F _R, which driving braking force F _L, so F _R are respectively obtained, the driving

device

64L, 64R, the

braking device

70L, 70R are controlled . In detail, in the case of F _L> 0, the magnitude of current according to Hidariwaka braking force F _L is supplied to the electromagnetic motor of the left wheel drive unit 64L from the battery. On the other hand, when F _L <0, the operation is as follows. Drive device 64, as described above, since it has a function as a regenerative braking device, when the Hidariwaka braking force F _L is covered by our regenerative braking force corresponding to Hidariwaka braking force F _L The left wheel drive device 64L is controlled such that a large current is generated by the electromagnetic motor of the left wheel drive device 64L and regenerated by the battery. If the Hidariwaka braking force F _L is not be covered by the regenerative braking force, the maximum regenerative braking force when the left wheel drive unit 64L so as to obtain is controlled, not be covered by the regenerative braking force of the maximum An electric current having a magnitude corresponding to the braking force is supplied to the electromagnetic motor of the left wheel braking device 70L so that a braking force corresponding to the minute can be obtained. Since the right wheel 14R is the same as the left wheel 14L, description thereof is omitted here.

As will be described in detail later, the left wheel driving braking force F _L and the right wheel driving braking force F _R are corrected based on the left and right wheel driving braking force difference ΔF required by the turning control. According to (7).
F _L = F _L + ΔF / 2 (6)
F _R = F _R −ΔF / 2 (7)
Therefore, when the vehicle is turning, driving

device

64L, 64R, the braking device 70L, control 70R is driving the left wheel of the corrected braking force F _L, it is performed based on Migiwaka braking force F _R.

b) Turning Control In this vehicle motion control, when the vehicle turns, the respective target of the front wheel turning angle δ _F that is the turning angle of the front wheel 12F and the rear wheel turning angle δ _R that is the turning angle of the rear wheel 12R. There is determined, front wheel steering amount control, the rear-wheel steering amount control is performed, the left wheel 14L, driving the braking force to be applied to each of the right wheel 14R F _L, the difference ΔF of Migiwaka braking force F _R is determined Thus, left and right wheel drive braking force difference control is performed. The turning control is a control for causing the vehicle to go straight when the operation angle θ of the steering wheel 20 is zero.

i) Front Wheel Turning Amount Control The turning angle δ _F of the front wheel 12F is controlled based on the operation angle θ that is the amount of operation of the steering wheel 20. First, based on the operation angle θ detected by the steering sensor 134, a target lateral acceleration Gy ^*, which is a lateral acceleration Gy to be generated in the vehicle during vehicle turning, is determined according to the following equation (8). That is, the target lateral acceleration Gy ^* is determined to have a magnitude corresponding to the operation angle θ. Incidentally, K _G is a lateral acceleration gain for determining the target lateral acceleration Gy ^*, may be constant, may be such a value by some parameters change.
Gy ^* = K _G · θ (8)
The actual lateral acceleration (actual lateral acceleration) Gy actually generated in the vehicle is acquired from the detection value of the lateral acceleration sensor 140, and the lateral acceleration deviation which is the deviation of the actual lateral acceleration Gy from the target lateral acceleration Gy ^* . ΔGy is certified according to the following equation (9).
ΔGy = Gy ^* −Gy (9)

Then, according to the feedback control law based on the lateral acceleration deviation Delta] Gy, the target front-wheel steering angle as a target front wheel steering angle [delta] _F [delta] _F ^* is determined. Specifically, the target front wheel turning angle δ _F ^* is determined according to the following equation (10) based on the PID control law.

The first term, the second term, and the third term on the right side of the equation (10) are a proportional term (P term), an integral term (I term), and a differential term (D term), respectively, and P _F , I _F , D _F are a proportional gain, an integral gain, and a differential gain for determining the target front wheel turning angle δ _F ^* . Note that these gains P _F , I _F , and D _F may all be constants, or values that change depending on some parameters. After determining the target front wheel turning angle δ _F ^* , the front wheel turning is performed such that the actual front wheel turning angle δ _F detected by the front wheel turning angle sensor 146F becomes the target front wheel turning angle δ _F ^*. The amount of current supplied to the electromagnetic motor included in the device 98F is determined, and the current corresponding to the amount of current is supplied to the electromagnetic motor. Instead of the control method, the amount of current supplied to the electromagnetic motor is directly determined by the above equation (10), and control is performed so that the current amount of current is supplied to the electromagnetic motor. May be.

ii) control to give the driving braking force F _L and a right wheel 14R of driving braking force F _R driving the braking force difference ΔF between the left and right wheels driving the braking force difference control the left wheel 14L, the operation angle θ and an operation amount of the steering wheel 20 , Based on the speed v at which the vehicle is traveling. First, based on the operation angle θ detected by the steering sensor 134 and the vehicle speed v detected by the vehicle speed sensor 132, a target yaw rate that is a yaw rate γ to be realized in vehicle turning according to the following equation (11): γ ^* is determined. That is, the target yaw rate γ ^* is determined to be a magnitude corresponding to the operation angle θ divided by the vehicle speed v. Incidentally, Kγ is a yaw rate gain for determining the target yaw rate γ ^* , and may be a constant or a value that changes depending on some parameter.
γ ^* = Kγ · θ · v (11)
The actual vehicle yaw rate (actual yaw rate) γ is obtained from the detection value of the yaw rate sensor 142. The yaw rate deviation Δγ, which is the deviation of the actual yaw rate γ from the target yaw rate γ ^* , is recognized according to the following equation (12).
Δγ = γ ^* −γ (12)

Then, the left and right wheel drive braking force difference ΔF to be realized is determined in accordance with the feedback control law based on the yaw rate deviation Δγ. Specifically, an appropriate left and right wheel drive braking force difference ΔF is determined according to the following equation (13) based on the PID control law.

The first term, the second term, and the third term on the right side of the above equation (13) are a proportional term (P term), an integral term (I term), and a differential term (D term), and P _LR and I _LR , D _LR are a proportional gain, an integral gain, and a differential gain for determining the left and right wheel drive braking force difference ΔF. Note that these gains P _LR , I _LR , and D _LR may all be constants, or values that change depending on some parameters. After the left and right wheel drive braking force difference ΔF is determined, the left wheel drive braking force F _L and the right wheel drive braking force F _R are corrected based on the left and right wheel drive braking force difference ΔF as described above. . Incidentally, when the operation angle θ of the steering wheel 20 is 0, that is, when the steering wheel is not operated, the left and right wheel drive braking force difference ΔF is determined to be 0.

iii) Rear wheel turning amount control The turning angle δ _R of the rear wheel 12R is controlled by the lateral acceleration deviation ΔGy certified in the front wheel turning amount control and the yaw rate deviation Δγ certified in the left and right wheel drive braking force difference control. Based on. First, based on the lateral acceleration deviation ΔGy and yaw rate deviation Δγ, the revolution centripetal acceleration deviation ΔGo is determined according to the following equation (14).
ΔGo = ΔGy−v · Δγ (14)
This revolution centripetal acceleration deviation ΔGo can be considered to be equivalent to the deviation of the actual revolution centripetal acceleration (actual revolution centripetal acceleration) Go from the target revolution centripetal acceleration Go ^* . Incidentally, the target revolution centripetal acceleration Go ^* is represented by the following equation (15), and the actual revolution centripetal acceleration Go is represented by the following equation (16).
Go ^* = Gy ^* −v · γ ^* (15)
Go = Gy−v · γ (16)

Then, according to the feedback control law based on the revolution centripetal acceleration deviation ΔGo, the target rear wheel turning angle δ _F ^{* which} is the target of the rear wheel turning angle δ _R is determined. Specifically, the rear wheel target turning angle δ _R ^* is determined according to the following equation (17) based on the PID control law.

The first term, the second term, and the third term on the right side of the equation (17) are a proportional term (P term), an integral term (I term), and a differential term (D term), and P _R , I _R , D _R is the proportional gain for determining the target rear wheel steering angle [delta] _F ^*, integral gain and derivative gain. Note that these gains P _R , I _R , and D _R may all be constants, or values that change depending on some parameters. After determining the target rear wheel turning angle δ _R ^* , the rear wheel turning is performed such that the actual rear wheel turning angle δ _R detected by the rear wheel turning angle sensor 146R becomes the target rear wheel turning angle δ _R ^*. The amount of current supplied to the electromagnetic motor included in the device 98R is determined, and the current corresponding to the amount of current is supplied to the electromagnetic motor. Instead of the above control method, the supply current amount to the electromagnetic motor is directly determined by the above equation (17), and control is performed so that the current amount of the current is supplied to the electromagnetic motor. May be.

iv) Front wheel and rear wheel steering and left and right wheel driving braking force difference by turning control Figure 5 shows the front and rear wheel steering and left and right wheel driving braking force difference in turning control. Conceptually. FIG. 5 shows a state in which the steering wheel 20 is operated counterclockwise, that is, when turning left, and FIG. 5A shows a case where the vehicle speed v is relatively high (hereinafter, “high speed” for convenience. FIG. 5B shows a case where the vehicle speed v is relatively low (hereinafter sometimes referred to as “low speed” for convenience). Incidentally, the operation angle θ of the steering wheel 20 is the same in both the case of FIG. 5A and the case of FIG. In the following description, for convenience, the case where the front wheels 12F and the rear wheels 12R, which are steered wheels, are steered so as to rotate counterclockwise when viewed from above is “steered to the left”. It is said that the case where the vehicle is turned so as to rotate clockwise is "turned to the right".

As can be seen from the figure, the front wheel 12F is naturally steered to the left at both high and low speeds. If the operation angle θ of the steering wheel 20 is the same at the high speed and the low speed, the target lateral acceleration Gy ^* is the same but the front wheel turning angle δ _F is constant according to the above equation (8). In this case, generally, the higher the vehicle speed v, the greater the lateral acceleration Gy obtained by turning the front wheel 12F. Therefore, as shown in FIG. 5, in this turning control, the various gains are generally set so that the front wheel turning angle δ _F is smaller at high speed than at low speed.

Further, according to the above equation (11), when the operation angle θ of the steering wheel 20 is constant, the target yaw rate γ ^* is made smaller at high speed than at low speed. Therefore, as shown in FIG. 5, the left and right wheel drive braking force difference ΔF is smaller at high speed than at low speed. Incidentally, in the figure, for convenience, it is shown that 1/2 each of the left and right wheel drive braking force difference ΔF is given in the direction of braking the left wheel 14L and given in the direction of driving the right wheel 14R. . Depending on whether the vehicle is accelerating or decelerating, the driving force difference or the braking force difference is determined. When the vehicle is accelerating, the driving force of the left wheel 14L is greater than the driving force of the right wheel 14R. Conversely, when the vehicle is decelerating, the braking force of the left wheel 14R is made larger than the braking force of the right wheel 14R. Thus, in this turning control, the various gains are set so that turning at a relatively low yaw rate is performed when the vehicle speed v is high, and turning at a relatively large yaw rate is performed when the vehicle speed v is low. .

The rear wheel 12R is steered to some extent, but simply speaking, as will be understood with reference to the above formulas (14) to (17), the revolution centripetal acceleration Go generated in the vehicle is the target. The rear wheel turning angle δ _R is steered so that the revolution centripetal acceleration Go ^* is obtained. Specifically, when the actual lateral acceleration Gy is smaller than the target lateral acceleration Gy ^* and the actual yaw rate γ is larger than the target yaw rate γ ^* , the rear wheel 12R is steered in the same direction as the front wheel 12F. That is, the rear wheel 12R is steered in phase with the front wheel 12F. On the contrary, when the actual lateral acceleration Gy is larger than the target lateral acceleration Gy ^* and the actual yaw rate γ is smaller than the target yaw rate γ ^* , the rear wheel 12R is steered in the opposite direction. That is, the rear wheel 12R is steered in the opposite phase to the front wheel 12F. As described above, in this turning control, when the vehicle speed v is high, turning at a relatively small yaw rate is performed, and when the vehicle speed v is low, turning at a relatively large yaw rate is performed. As shown, when the vehicle speed v is high, the vehicle is generally steered to the left, which is the same direction as the front wheels 12F. In other words, the rear wheel turning angle δ _R is set so as to assist the approach of the actual lateral acceleration Gy to the target lateral acceleration Gy ^{* due} to the turning of the front wheel 12F, and the left and right wheel drive braking force difference ΔF. The angle is set so as to assist the approach of the actual yaw rate γ to the target yaw rate γ ^* by the above control. The various gains are set so that the rear wheel 12R is steered.

v) Effect of turning control It is assumed that turning is performed such that the lateral acceleration Gy generated in the vehicle becomes a certain target lateral acceleration Gy ^* and the yaw rate γ becomes a certain target yaw rate γ ^* . A time change of the lateral acceleration Gy and the yaw rate γ is compared between the case where the turning is performed only by turning the front wheel 12F and the case where the same turning is performed under the turning control. FIG. 6 is a graph showing the results of this comparison. FIG. 6A shows a comparison for the lateral acceleration Gy, and FIG. 6B shows a comparison for the yaw rate γ. In both figures, the solid line represents the change when turning under the turning control, and the broken line represents the change when turning only by turning the front wheel 12F. Incidentally, any change in any case is a change on the premise that the steering wheel 20 is operated stepwise to a certain operation angle θ.

As can be seen from FIG. 6A, in the turn under the turn control described above, the lateral acceleration Gy reaches the target lateral acceleration Gy ^* in a relatively short time, whereas in the turn only by turning the front wheel 12F. It takes a relatively long time for the lateral acceleration Gy to reach the target lateral acceleration Gy ^* . Further, as can be seen from FIG. 6B, in the turn under the turn control, the yaw rate γ reaches the target yaw rate γ ^* in a relatively short time, whereas the front wheel 12F, as in the case of the lateral acceleration Gy. In the turning by only turning, it takes a relatively long time for the yaw rate γ to reach the target yaw rate γ ^* . From this result, according to the turning control described above, both the followability to the change in the target lateral acceleration Gy ^* (responsiveness for the lateral acceleration Gy) and the followability to the change in the target yaw rate γ ^* (responsiveness to the yaw rate γ). In both cases, a good turn is realized.

Next, referring to FIG. 7, changes in the lateral acceleration Gy and yaw rate γ under the above-described turning control when a lane change is performed within a certain time, and those in the case of only turning the front wheel 12F Compare changes. Incidentally, FIG. 7 shows changes when a lane change is performed in 2 seconds. FIG. 7A shows changes in the lateral acceleration Gy, and FIG. 7B shows changes in the yaw rate γ. In the figure, the change in the target lateral acceleration Gy ^* or the target yaw rate γ ^* is indicated by a one-dot chain line, the change in the lateral acceleration Gy or the yaw rate γ under the turning control is a solid line, and the front wheel 12F is steered. Those changes due to only are respectively represented by broken lines.

As can be seen from FIG. 7 (a), also in the lane change, according to the turning control, the followability to the change in the target lateral acceleration Gy ^* is better than in the case where only the front wheel 12F is steered. Further, as can be seen from FIG. 7B, the followability to the change of the target yaw rate γ ^* is good.

c) shared load ratio change control or less, the amount of the front wheel 12F and rear wheel 12R of the vehicle body weight is shared, and the front and rear wheel shared load W _FR, the amount that the left wheel 14L and the right wheel 14R is shared, the left and right wheels sharing the load W _LR, represent respectively, the ratio of the left and right wheels shared load W _LR for the front and rear wheels shared load W _FR, will be represented with the shared load ratio _{_{Rw (= W LR / W FR}} ). In this vehicle motion control, the shared load ratio Rw is controlled.

i) Contents of shared load ratio change control As described above, the upper end portions of the suspension springs 46 that support the left wheel 14L and the right wheel 14R are respectively connected to the left wheel spring support position adjusting device 44L and the right wheel spring support position. It is attached to the vehicle body via an adjusting device 44R. Considering the vehicle body as a rigid body, for example, if the spring support position adjusting device 44 lowers the position of each upper end of the suspension spring 46 relative to the vehicle body, that is, if the spring support position is lowered, the suspension spring 46 is compressed. The spring reaction force of the suspension spring 46 increases and the vehicle body rises to some extent. Accordingly, the suspension spring 108 that supports the front wheel 12F and the rear wheel 12R is extended, and the spring reaction force thereof decreases. As a result, the front / rear wheel shared load _WFR decreases, and the left / right wheel shared load _WLR increases, thereby increasing the shared load ratio Rw. Conversely, when the spring support position is raised by the spring support position adjusting device 44, the suspension spring 46 supporting the left wheel 14L and the right wheel 14R is extended, and the suspension spring 108 supporting the front wheel 12F and the rear wheel 12R is extended. It is shortened. As a result, the front and rear wheel shared load _WFR increases and the left and right wheel shared load _WLR decreases, so that the shared load ratio Rw increases. In this vehicle, the shared load ratio Rw is changed in this way.

In view of the above, the left wheel spring support position adjustment device 44L and the right wheel spring support position adjustment device 44R respectively determine the distance in the vertical direction between the left wheel 14L and the vehicle body and the distance in the vertical direction between the right wheel 14R and the vehicle body. By generating a force in the changing direction, it functions as a shared load ratio changing device that changes the shared load ratio Rw.

The distance between the upper end of the suspension spring 46 provided on the left wheel 14L and the mounting portion of the vehicle body (left wheel side mounting interval) h _L , and the distance between the upper end of the suspension spring 46 provided on the right wheel 14R and the mounting portion of the vehicle body (Right wheel side mounting interval) h _R is detected by the left wheel spring support position sensor 144L and the right wheel spring support position sensor 144R, respectively. Specifically, in the shared load ratio change control, the left wheel side mounting interval h _L and the right wheel side mounting interval h _R are respectively set as a target left wheel side mounting interval h _L ^* and a target right wheel side mounting interval h _R ^* . Thus, the current supply to the electromagnetic motor of each of the left wheel spring support position adjusting device 44L and the right wheel spring support position adjusting device 44R is controlled.

This shared load ratio change control is performed based on the vehicle speed v. Specifically, the shared load ratio Rw is controlled to be smaller when the vehicle speed v is high than when it is low. Specifically, the shared load ratio Rw is controlled so as to change as shown in FIG. 8 according to the vehicle speed v. Specifically, the shared load ratio Rw to be realized is determined with reference to map data set according to the vehicle speed v and stored in the ECU 130, and based on the determined shared load ratio Rw, The target left wheel side mounting interval h _L ^* and the target right wheel side mounting interval h _R ^* are determined according to the following equations (18) and (19).
h _L ^* = f _L (Rw) (18)
h _R ^* = f _R (Rw) (19)
Note that f _L (Rw) and f _R (Rw) are functions for determining the target left wheel side mounting interval h _L ^* and the target right wheel side mounting interval h _R ^* using the shared load ratio R as a parameter. Stored in After the target left wheel side mounting interval h _L ^* and the target right wheel side mounting interval h _R ^* are determined, the left wheel side mounting interval h _L and the right wheel side mounting interval h _R are determined as the determined target left wheel side mounting interval. The left wheel spring support position adjusting device 44L and the right wheel spring support position adjusting device 44R are controlled so that the interval h _L ^* and the target right wheel side mounting interval h _R ^* are obtained.

More specifically, with regard to the change in the shared load ratio Rw as shown in FIG. 8, the shared load ratio Rw is determined when the vehicle speed v exceeds a certain threshold vehicle speed (first threshold vehicle speed) v ₁ . It is controlled so as to continuously decrease in accordance with the increase. When the vehicle speed v is lower than a certain threshold vehicle speed (second threshold vehicle speed) v ₂ , the front and rear wheel shared load W _FR is smaller than the left and right wheel shared load W _LR , and the vehicle speed v is higher than the threshold speed v _2. case, the front and rear wheels shared load W _FR is larger than the left and right wheel shared load W _LR. Incidentally, if the閾車speed v ₂ which is the vehicle speed v has a front and rear wheel shared load W _FR left and right wheels shared load W _LR are equal to each other, shared load ratio Rw is 1.

According to the shared load ratio change control, the vehicle body load is shared between the front wheel 12F and the rear wheel 12R, and the left wheel 14L and the right wheel 14R as conceptually shown in FIG. FIG. 9A shows the state of load sharing when the vehicle speed v is high, and FIG. 9B shows the state of load sharing when the vehicle speed v is high. Incidentally, in order to simplify the explanation, in the figure, the shared load of the front wheel 12F and the shared load of the rear wheel 12R are treated as being equal to each other.

i) Effect by shared load ratio change control Since this vehicle is a vehicle with rhombus wheels, high straight running stability is required particularly at high speeds. Therefore, it is possible to improve the straight running stability by reducing the shared load ratio Rw at high speeds, that is, by relatively increasing the front and rear wheel shared load _WFR . Further, by increasing the shared load ratio Rw at a low speed, that is, by relatively increasing the left and right wheel shared load _WLR , it becomes possible to improve the driving performance of the vehicle.

The movement of the vehicle during turning will be described with reference to FIG. In addition, Fig.10 (a) is a figure for demonstrating the exercise | movement at the time of high speed, the left figure made the shared load ratio Rw small when the shared load ratio Rw was set to 1, and the right figure made the shared load ratio Rw small. Each case is shown. FIG. 10B is a diagram for explaining the motion at a low speed. The left diagram shows a case where the shared load ratio Rw is 1, and the right diagram shows a case where the shared load ratio Rw is increased. , Respectively.

At high speed, as described above, turning with a relatively low yaw rate γ is desired, and the front wheels 12F and the rear wheels 12R are steered in phase with each other. At that time, as can be seen from FIG. 10A, the friction between the left wheel 14L and the right wheel 14R and the road surface (white arrow) is a great resistance against turning of the vehicle. Therefore, when the desired lateral acceleration Gy is to be obtained, both the front wheel turning angle δ _F and the rear wheel turning angle δ _R are increased. By performing the shared load ratio change control, at high speeds, because the left and right wheels shared load W _LR it is relatively small, reduces the ground contact load of the left wheel 14L, right wheel 14R, the resistance to turning of the vehicle is reduced. As a result, since the front wheel turning angle δ _F and the rear wheel turning angle δ _R can be small, the burden during turning can be reduced. On the other hand, since the front and rear wheel share load W _FR is relatively large, the lateral acceleration Gy generated by the front wheels 12F and the rear wheels 12R is increased, and this also means that the front wheel turning angle δ _F and the rear wheels are increased. This contributes to reducing the wheel turning angle δ _R.

At low speed, as described above, turning with a relatively high yaw rate γ is desired. At that time, as can be seen from FIG. 10B, the friction between the front wheel 12F and the rear wheel 12R and the road surface (white arrow) is a great resistance against turning of the vehicle. Therefore, when turning at a desired yaw rate γ, the left and right wheel drive braking force difference ΔF must be increased (see the thick black arrow). By performing the shared load ratio change control, the front and rear wheel shared loads _WFR are relatively reduced at low speeds, so that the ground load on the front wheels 12F and the rear wheels 12R is reduced and the resistance to turning of the vehicle is reduced. As a result, the left and right wheel drive braking force difference ΔF can be reduced. As described above, the direction of turning of the rear wheel 12R is determined depending on various gains for determining the target rear wheel turning angle δ _F ^* , but FIG. As shown in FIG. 5B, the resistance of the front wheels 12F and the rear wheels 12R with respect to turning of the vehicle may be steered in the same phase as the front wheels 12F, contrary to the case where the shared load ratio change control is not performed.

FIG. 11 is a graph group for explaining a comparison between the case where the shared load ratio change control is performed and the case where it is not performed in the 2-second lane change when the vehicle speed v is 100 km / h. FIG. 12 is a graph group for explaining a comparison between the case where the shared load ratio change control is performed and the case where it is not performed in the 2-second lane change when the vehicle speed v is 10 km / h. Each figure shows the components of the target lateral acceleration Gy ^* , the target yaw rate γ ^* , the front wheel turning angle δ _F , the rear wheel turning angle δ _R , and the left and right wheel drive braking force difference ΔF for the left wheel (ΔF / It is configured by a graph for each change of 2). Each graph shows that the maximum yaw rate during the lane change is the same when the vehicle speed v is 100 km / h and when the vehicle speed v is 10 km / h, and the maximum lateral acceleration Gy is the vehicle speed v is 100 km / h. The result in the lane change under the condition that it is about 10 times that at 10 km / h is shown. When the vehicle speed v is 100 km / h, the shared load ratio Rw is about 0.74, and when the vehicle speed v is 10 km / h, the shared load ratio Rw is about 1.35. Incidentally, the solid lines in the respective graphs of the front wheel turning angle δ _F , the rear wheel turning angle δ _R , and the left and right wheel drive braking force difference ΔF component (ΔF / 2) for the left wheel are when the shared load ratio change control is performed. The broken line represents the change when the shared load ratio change control is not performed.

As can be seen from FIG. 11, at the time of high speed, since the shared load ratio Rw is reduced and the left and right wheel shared load _WLR is relatively reduced, when the shared load ratio change control is performed, it is not performed. In comparison, the front wheel turning angle δ _F and the rear wheel turning angle δ _R are smaller. Also, as can be seen from FIG. 12, at low speed, the shared load ratio Rw is increased and the front and rear wheel shared load _WFR is relatively reduced, so the left and right wheel drive braking force difference ΔF component (ΔF The component of / 2) becomes small. That is, the left and right wheel drive braking force difference ΔF is reduced. At low speeds, the direction of turning of the rear wheels 12R is the same as the direction of turning of the front wheels 12F by performing the shared load ratio change control for the reason described above.

≪Function of vehicle motion control program and control device≫
The vehicle motion control by this vehicle motion control system is performed by the ECU 130 as a control device executing a vehicle motion control program whose flowchart is shown in FIG. This program is repeatedly performed at a short time pitch (for example, several to several tens of microseconds). In this program, first, in step 1 (hereinafter, step is abbreviated as “S”), the vehicle speed v is acquired, and then in S2, the operation angle θ of the steering wheel 20 is acquired. After these acquisitions, turning control is performed in S3, acceleration / deceleration control is performed in subsequent S4, and shared load ratio change control is performed in further subsequent S5.

In the turning control of S3, a turning control subroutine whose flowchart is shown in FIG. 14 is executed. In this subroutine, front wheel steering amount control is performed in S10, left and right wheel drive braking force difference control is performed in S20, and rear wheel steering amount control is performed in S30. The front wheel turning amount control, the left and right wheel driving braking force difference control, and the rear wheel turning amount control are respectively a front wheel turning amount control subroutine shown in a flowchart in FIG. 15, and a left and right wheel driving braking force difference shown in a flowchart in FIG. The control subroutine and the rear wheel turning amount control subroutine shown in the flowchart of FIG. 17 are executed. Since processing according to these subroutines has been described in detail earlier, description thereof will be omitted here.

In the acceleration / deceleration control in S4, the acceleration / deceleration control subroutine shown in the flowchart in FIG. 18 is executed, and in the shared load ratio change control in S5, the shared load ratio change control subroutine shown in the flowchart in FIG. 19 is executed. Since processing according to these subroutines has also been described in detail earlier, description thereof will be omitted here.

The ECU 130 that executes the vehicle motion control program can be considered to have a functional unit that executes the above-described controls as shown in FIG. Specifically, the ECU 130 executes the turning control unit 160 as a functional unit that executes the turning control, the acceleration / deceleration control unit 162 as a functional unit that executes the acceleration / deceleration control, and the shared load ratio change control. It can be considered that it has a shared load ratio change control unit 164 as a functional unit. The turning control unit 160 includes a front wheel turning amount control unit 166 as a functional unit that executes the front wheel turning amount control, and a left and right wheel driving unit as a functional unit that executes the left and right wheel driving braking force difference control. It can be considered that the power difference control unit 168 and the rear wheel turning amount control unit 170 as a functional unit that executes the rear wheel turning amount control are included.

10: Vehicle body 12F: Front wheel 12R: Rear wheel 14L: Left wheel 14R: Right wheel 20: Steering wheel (steering operation member) 44L: Left wheel spring support position adjusting device (shared load ratio changing device) 44R: Right wheel spring supporting position adjusting device (Shared load ratio changing device) 46: Suspension spring 64L: Left wheel drive device 64R: Right wheel drive device 70L: Left wheel brake device 70R: Right wheel brake device 98F: Front wheel steering device 98R: Rear wheel steering device 130: Electronic control unit (ECU) (Control Device) 164: Shared Load Ratio Change Control Unit 166: Front Wheel Steering Amount Control Unit 168: Left / Right Wheel Driving Braking Force Difference Control Unit 170: Rear Wheel Steering Amount Control Unit

Claims

A single front wheel located at the front of itself, a left wheel and a right wheel respectively located on the left and right sides behind the front wheel, and a single rear located behind the left wheel and the right wheel A vehicle motion control system for controlling motion of a vehicle having wheels,
A front wheel steering device for steering the front wheels;
A left wheel driving braking device and a right wheel driving braking device for applying a driving braking force, which is a force for driving and braking the vehicle, to the left wheel and the right wheel, respectively;
It is a ratio of left and right wheel shared load that is a share of the left wheel and the right wheel to a front and rear wheel share load that is a share of the front wheel and the rear wheel of the weight of the vehicle body. A shared load ratio changing device for changing the shared load ratio;
A control device for controlling the vehicle,
The control device is
The vehicle motion control system which has a shared load ratio change control part which controls the said shared load ratio by controlling the said shared load ratio change apparatus.
The vehicle motion control system according to claim 1, wherein the shared load ratio change control unit is configured to control the shared load ratio based on a traveling speed of the vehicle.
The shared load ratio changing control unit is configured to control the shared load ratio changing device so that the shared load ratio becomes smaller when the traveling speed of the vehicle is high than when the vehicle is low. The vehicle motion control system according to 2.
The shared load ratio change control unit is configured such that when the vehicle traveling speed is higher than a set threshold speed, the front and rear wheel shared load is larger than the left and right wheel shared load, and the vehicle traveling speed is set to the set threshold value. 4. The vehicle motion control system according to claim 2, wherein the shared load ratio changing device is controlled so that the front and rear wheel shared load becomes smaller than the left and right wheel shared load when the speed is lower than a speed. 5.
The left wheel driving braking device and the right wheel driving braking device are configured to be able to apply the driving braking force to the left wheel and the right wheel independently of each other,
The control device is
When the vehicle turns, the left wheel drive braking device and the right wheel drive braking device are controlled to control a left and right wheel drive braking force difference that is a difference between the left wheel drive braking force and the right wheel drive braking force. The vehicle motion control system according to any one of claims 1 to 4, further comprising a left and right wheel driving braking force difference control unit.
The left and right wheel drive braking force difference control unit determines a target yaw rate that is a yaw rate to be realized in turning of the vehicle based on an operation of a steering operation member, and an actual yaw rate that is actually generated in the vehicle The vehicle motion control system according to claim 5, configured to control the difference between the left and right wheel driving braking forces so as to approach the target yaw rate.
The control device is
A front wheel turning amount control unit that controls the front wheel turning device to control the turning amount of the front wheel during turning of the vehicle;
The front wheel turning amount control unit determines a target lateral acceleration that is a lateral acceleration that should be generated in the vehicle during the turning of the vehicle based on the operation of the steering operation member, and the lateral acceleration actually generated in the vehicle is determined. The vehicle motion control system according to any one of claims 1 to 6, configured to control a turning amount of the front wheel so that a certain actual lateral acceleration approaches the target lateral acceleration.
The control device is
The vehicle motion control system according to claim 7, further comprising a rear wheel turning amount control unit that controls a rear wheel turning device to control a turning amount of the rear wheel during turning of the vehicle.
The left wheel driving braking device and the right wheel driving braking device are configured to be able to apply the driving braking force to the left wheel and the right wheel independently of each other,
The control device is
When the vehicle turns, the left wheel drive braking device and the right wheel drive braking device are controlled to control a left and right wheel drive braking force difference that is a difference between the left wheel drive braking force and the right wheel drive braking force. The left and right wheel drive braking force difference control unit
The left and right wheel drive braking force difference control unit determines a target yaw rate that is a yaw rate to be realized in turning of the vehicle based on the operation of the steering operation member, and an actual yaw rate that is actually generated in the vehicle The vehicle motion control system according to claim 8, wherein the vehicle motion control system is configured to control the difference between the left and right wheel drive braking forces so as to approach the target yaw rate.
The rear wheel turning amount control unit is realized by the approach of the actual lateral acceleration to the target lateral acceleration realized by the control by the front wheel turning amount control unit and the control by the left and right wheel drive braking force difference control unit. The vehicle motion control system according to claim 9, wherein the steering amount of the rear wheel is controlled such that at least one of the actual yaw rate and the approach to the target yaw rate is assisted.