JP5516498B2 - Vehicle behavior control device - Google Patents

Description

  The present invention relates to a technical field of a behavior control device in a vehicle capable of controlling a vehicle state quantity independently of driver steering.

  As this type of device, there is one that realizes a first control that places importance on lane tracking and a second control that easily reflects the driver's steering operation (see, for example, Patent Document 1).

  According to the lane keeping assist device disclosed in Patent Literature 1, when shifting from the first control to the second control, in the second control, an addition equal to the additional torque calculated in the immediately preceding first control in a predetermined period. By calculating the torque, it is possible to prevent torque fluctuations unpleasant for the driver in any steering operation state of the driver, and to perform lane keeping control that is comfortable for the driver. Has been.

JP 2010-195088 A

  Under normal steering control that reflects the driver's steering intention, the steering wheel as a means for the driver to reflect the steering intention in the vehicle behavior (the “handle” in this specification includes a steering wheel as a representative form. On the other hand, the range in which a certain vehicle state quantity can be taken is greatly limited with respect to the handle angle, which is an operation angle of a steering input means capable of being steered by a driver. For example, when the yaw rate is taken as an example of this kind of vehicle state quantity, the yaw rate with respect to the steering wheel angle is unambiguous except for the influence of various parameters such as vehicle speed and road surface friction.

  On the other hand, in various types of automatic steering control in which the vehicle state quantity is controlled independently of the driver's intention, for example, the steering angle of the front wheel and / or the rear wheel while the steering wheel angle is maintained at the neutral position equivalent angle. It is also possible to maintain these vehicle state quantities at a desired value while appropriately changing the value, and this type of vehicle state quantity can have a high degree of freedom with respect to the steering wheel angle. At this time, if the driver does not have a positive intention to steer, any uncomfortable feeling on the driver side will not occur regardless of the amount of vehicle state relative to the steering wheel angle.

  Therefore, when the automatic steering control is switched to the driver steering, the vehicle state quantity may deviate from the vehicle state quantity that is unambiguous with respect to the steering wheel angle immediately after the steering sovereignty is transferred to the driver. is there. As described above, when the vehicle state quantity deviates from the vehicle state quantity that should originally occur with respect to the steering wheel angle, the driver feels uncomfortable, uncomfortable or uneasy.

  In conventional devices (including those disclosed in the above-mentioned patent documents), such incongruity, discomfort, or anxiety is not realized because of such inconsistency in the vehicle state quantity immediately after the start of driver steering. It was a factor that decreased drivability.

  The present invention has been made in view of such circumstances, and at the time of switching from automatic steering control to driver steering, it is possible to transfer the steering sovereignty to the driver without causing discomfort, discomfort or anxiety. It is an object of the present invention to provide a vehicle behavior control device.

In order to solve the above-described problem, a vehicle behavior control device according to the present invention is a vehicle that controls the behavior of a vehicle including at least one device capable of changing a vehicle state quantity independently of driver steering. An automatic steering control execution for performing an automatic steering control for converging the vehicle state quantity to a target state quantity via a target apparatus that is at least one of the at least one apparatus. Means for detecting a steering wheel angle, and when the automatic steering control is switched to driver steering in accordance with driver steering, the vehicle state quantity correlated with the steering wheel angle in the driver steering, The first state quantity generated by the automatic steering control and the second state quantity to be generated with respect to the detected steering wheel angle coincide with each other. A state quantity matching means for controlling the Kutomo one device, when the automatic steering control is in the at least one abnormal condition of the target device when switched to the driver steering the subject among the at least one device As an alternative device to be replaced with at least one of the remaining devices other than the device, there is a state control amount required when the first state quantity and the second state quantity are matched. The automatic steering control execution means continues the automatic steering control using the selected alternative device (Claim 1).

  The vehicle state quantity according to the present invention is a concept encompassing state quantities that can affect the behavior of the vehicle, and preferably, for example, yaw rate, yaw moment, vehicle body slip angle, lateral acceleration, self-aligning torque, etc. Means. The vehicle according to the present invention includes at least one device capable of changing such a vehicle state quantity, and each device is in a state as a direct control target for indirectly changing the vehicle state quantity. The configuration has at least one control amount.

  For example, the device includes a front wheel steering angle variable means such as VGRS (Variable Gear Ratio Steering) that uses the front wheel steering angle as a state control amount, and a rear wheel such as ARS (Active Rear Steering) that uses the rear wheel steering angle as a state control amount. Steering angle variable means, braking force variable means such as ECB (Electronic Control Braking system) that uses the left and right braking force difference as the state control amount, driving force distribution differential mechanism or in-wheel motor system that uses the left and right driving force difference as the state control amount, etc. The driving force variable means or auxiliary steering torque supply means such as EPS (Electronic Control Power Steering) using the torque around the kingpin axis or the steering reaction torque as the state control amount may be used.

  The vehicle behavior control device according to the present invention is a device for controlling the behavior of such a vehicle. For example, one or a plurality of CPUs (Central Processing Units), MPUs (Micro Processing Units), various processors, or various controllers. Alternatively, various processing units such as a single or plural ECUs (Electronic Controlled Units), which may appropriately include various storage means such as ROM (Read Only Memory), RAM (Random Access Memory), buffer memory or flash memory Various computer systems such as various controllers or microcomputer devices can be used.

  According to the vehicle behavior control apparatus of the present invention, automatic steering control is executed by the automatic steering control execution means during the operation.

  The “automatic steering control” according to the present invention is control for converging the vehicle state quantity to the target state quantity via the target apparatus that is at least one of the above-described at least one apparatus, and is independent of the driver's steering. (Of course, the driver's intention is reflected as to whether or not the automatic steering control should be started). Normally, one state control amount is assigned to one device, and the number of state control amounts is equal to the degree of freedom of vehicle motion. Therefore, typically, the number of target devices can be unambiguous with the quantity of vehicle state quantities that it is desired to control independently of each other. Conceptually, there is no limitation on the selection criteria for selecting a target device from “at least one device” according to the present invention. Further, the case where there is no need for “selection” (for example, a case where it is determined in advance) is also within the scope of the present application.

  In addition, although the practical aspect of such automatic steering control is not limited uniquely, for example, automatic steering control makes lane maintenance driving | running | working control, such as LKA (Lane Keeping Assist), and the target driving | running route set in advance follow. The target travel path following control may be used. In these controls, for example, a state control amount (for example, a front wheel steering angle, a rear wheel steering angle, a front wheel left / right braking / driving force difference and a rear wheel left / right braking / driving force difference) is appropriately selected (selection criterion). For example, the yaw rate and the vehicle body slip angle are controlled independently of each other by the control of two state control amounts determined in advance for each automatic steering control.

  Here, since the automatic steering control is a control independent of the steering of the driver, the vehicle state quantity to be controlled is unambiguous with respect to the steering wheel angle or the steering wheel angle in the driver steering according to the steering of the driver via the steering wheel. As for the vehicle state quantity whose range that can be taken is greatly limited, a high degree of freedom with respect to the steering wheel angle can be maintained. For example, it is possible to change the steering angle to the front wheel and / or the rear wheel while maintaining the steering wheel in the neutral position (the steering wheel position determined to be the steering wheel angle = 0) to generate the yaw rate or yaw moment in the vehicle. Yes, conversely, for a non-zero steering angle, the vehicle is driven straight by changing the steering angle to the front wheels and / or rear wheels (“straight” means that the vehicle state quantity in the yaw direction is zero The traveling direction of the vehicle may be the longitudinal direction of the vehicle (that is, the vehicle body slip angle = 0), or may intersect with the longitudinal direction of the vehicle (that is, the vehicle body slip angle ≠ 0). You can also.

  By the way, when the steering mode is switched from automatic steering control to driver steering, the steering wheel angle immediately after the steering sovereignty is transferred to the driver is usually equal to the steering wheel angle in automatic steering control. Therefore, immediately after the transfer of the steering sovereignty to the driver, for this type of vehicle state quantity, the actual vehicle state quantity (first state quantity) and the vehicle state quantity that should originally occur with respect to the steering angle at that time ( There is a possibility that the driver may feel uncomfortable, uncomfortable or uneasy due to a deviation from the second state quantity.

  For example, when the automatic steering control that appropriately gives the vehicle a yaw behavior while maintaining the steering wheel angle at the neutral point as described above, the driver performs the yaw behavior on the vehicle even though the steering wheel angle is the neutral point. This causes a sense of discomfort, discomfort, or anxiety, resulting in a decrease in drivability. Similarly, when switching from automatic steering control that drives the vehicle straight at a non-zero steering angle to driver steering, the driver feels uncomfortable that the yaw behavior does not occur in the vehicle even though the steering angle is not neutral. This will cause discomfort or anxiety, leading to a decrease in drivability.

  In order to suppress a decrease in drivability associated with such steering mode switching, the vehicle behavior control device according to the present invention includes a handle angle detection unit and a state quantity matching unit.

  The state quantity matching means is a first state generated by the automatic steering control for one vehicle state quantity determined to correlate with the steering wheel angle at the time of driver steering when switching the steering form from automatic steering control to driver steering. At least one device including the above-described target device is controlled so that the amount matches the second state amount that should originally occur with respect to the handle angle detected by the handle angle detecting means.

  Here, “so as to match” does not only indicate that the deviation between the first state quantity and the second state quantity is zero, but changes at least one state quantity in a direction in which the deviation decreases. It is a concept that broadly includes At this time, as a preferred embodiment, the deviation is converged to an experimentally, empirically, or theoretically set allowable range so as not to cause the driver to feel uncomfortable, uncomfortable or uneasy. May be taken.

  As described above, the second state quantity as the vehicle state quantity that should originally occur with respect to the steering wheel angle is uniquely determined if the vehicle traveling condition at that time is determined (may be determined as an allowable range). Thus, the deviation between the first state quantity substantially equal to the control target in the automatic steering control and the second state quantity is known when the steering control mode is switched. The state quantity matching means can match these based on the deviation or referring to the deviation.

  Note that the practical control mode of the state quantity matching means when matching the first state quantity and the second state quantity is that the steering sovereignty is transferred to the driver in a state where the first state quantity and the second state quantity are deviated. As long as this kind of uncomfortable feeling, discomfort or anxiety can be suppressed, there is no limitation.

  For example, the state quantity matching means may make the second state quantity asymptotically approach the first state quantity (that is, change the handle angle by turning the handle up or down). Further, the first state quantity may be asymptotic to the second state quantity (that is, the target state quantity may be changed from such a purpose at the end of the execution period of the automatic steering control). Alternatively, both the first state quantity and the second state quantity may be asymptotic to each other.

As described above, according to the vehicle behavior control apparatus of the present invention, when the control mode is switched from the automatic steering control to the driver steering, the first state quantity generated by the automatic steering control and the detected steering wheel angle are determined. The second state quantity to be generated is matched with the second state quantity. That is, the steering sovereignty is transferred to the driver in a state where an appropriate vehicle state amount corresponding to the steering wheel angle is obtained. Therefore, when the control mode is switched, the driver does not feel uncomfortable, uncomfortable or uneasy, and a smooth and natural steering feel is realized.
In the vehicle behavior control device according to the present invention, when at least one of the target devices falls into an abnormal state, an alternative device is selected from the remaining devices. When selecting an alternative device, the selection means selects a device having the smallest state control amount required when the first state quantity and the second state quantity are matched. In many cases, the state control amount is different for each apparatus. The “minimum” in such a case may be defined as the minimum index value for comparison standardized with respect to the controllable range of the state control amount.
Such an apparatus that minimizes the state control amount necessary for making the first state quantity and the second state quantity coincide with each other causes the vehicle state quantity to be controlled by automatic steering control and the apparatus to enter an abnormal state. It is possible to determine in advance experimentally, empirically, or theoretically as a parameter the device that has been used in the automatic steering control that has been executed before.
If the control amount for matching the first state amount and the second state amount is minimum, the state control that has been changed independently of the driver's steering by the automatic steering control after the steering sovereignty is transferred to the driver The amount of change in the state control amount can be minimized when the amount is returned to the value according to the driver steering and the steering mode is completely switched from the automatic steering control to the driver steering. It becomes possible to relieve the driver's discomfort, discomfort or anxiety during the period.

  In one aspect of the vehicle behavior control apparatus according to the present invention, the one vehicle state quantity is a yaw rate.

  The yaw rate has a high correlation with the steering wheel angle in driver steering, and is appropriate as the “one vehicle state quantity” according to the present invention.

  In another aspect of the vehicle behavior control apparatus according to the present invention, the state quantity matching means matches the second state quantity with the first state quantity (Claim 3).

  According to this aspect, it occurs with respect to the detected steering wheel angle on the premise that the steering wheel angle can be changed directly or indirectly as at least one device capable of changing the vehicle state quantity. At least one device is controlled to match the second state quantity to be matched with the first state quantity generated by the automatic steering control. That is, more specifically, the steering wheel angle is changed via a corresponding device (for example, front wheel steering angle variable means such as VGRS) so as to obtain a steering wheel angle that matches the first state quantity.

  Therefore, according to this aspect, it is possible to switch the steering control mode to driver steering in the form of taking over the vehicle state quantity by the automatic steering control, for example, ending the lane keeping control or the target travel path following control naturally and smoothly. It becomes possible to make it.

  In another aspect of the vehicle behavior control apparatus according to the present invention, the state quantity matching means matches the first state quantity with the second state quantity.

  According to this aspect, the first state quantity generated by the automatic steering control is changed so as to match the second state quantity to be generated with respect to the detected steering wheel angle. For example, the target state quantity at the end of automatic steering control is forcibly changed. Alternatively, another automatic steering control specialized for the transition period immediately after the end of the automatic steering control is executed.

  Here, when the first state quantity is set as the control target related to the matching, the first state quantity and the second state quantity are provided even if the vehicle does not have a device capable of changing the steering wheel angle as at least one device. Can be matched. Further, when it is desired to maintain the steering wheel angle when switching the steering control mode, or as a result of changing the steering wheel angle so that the second state quantity matches the first state quantity, an unintended change in the vehicle state quantity occurs. Even when it occurs, it is possible to prevent the driver from feeling uncomfortable, uncomfortable or uneasy.

  For example, a part of the target device used for the automatic steering control is in an abnormal state (here, “abnormal state” means a state that is not a normal state as an originally expected state. From the viewpoint of fail-safe, avoid the forced termination of the automatic steering control during turning behavior, and wait for the vehicle to go straight ahead before performing the automatic steering control. It may be forcibly terminated.

  Here, the straight traveling state of the vehicle in this case means that the vehicle state quantity that defines the yaw behavior, such as the yaw rate and the yaw moment, is a value corresponding to zero, and the steering wheel angle is not necessarily a value corresponding to zero. Therefore, if the steering wheel angle is changed to a value corresponding to zero in order to match the second state quantity with the first state quantity, yaw behavior that has not occurred until then may occur due to the change in the steering wheel angle.

  For example, this aspect is remarkably effective in such a case, and by making the first state quantity coincide with the second state quantity, it is possible to prevent the driver from feeling uncomfortable, uncomfortable or uneasy. .

  In another aspect of the vehicle behavior control apparatus according to the present invention, the state quantity matching means includes the first state quantity and the second state quantity in accordance with a deviation between the first state quantity and the second state quantity. The degree of matching with the state quantity is changed (claim 5).

  According to this aspect, according to the deviation between the first state quantity and the second state quantity, the degree of matching both in a binary, stepwise or continuous manner is changed. Therefore, it is possible to perform efficient control in consideration of the magnitude of profit obtained when the first state quantity and the second state quantity are matched.

  For example, the state quantity matching means may match both only when the deviation exceeds a preset reference value. At this time, if such a reference value is set in advance as a value experimentally, empirically, or theoretically determined that the driver does not feel uncomfortable, uncomfortable or uneasy in a region below (below) Unnecessary matching between the first state quantity and the second state quantity is avoided, which is remarkably effective.

  Alternatively, the state quantity matching unit may switch the convergence target of the deviation step by step according to the magnitude of the deviation. More specifically, when the deviation is large (small), the allowable value of the deviation remaining after matching may be increased (decreased). In this way, it is possible to prevent an excessive load from being applied to the device used for matching the state quantities.

  In another aspect of the vehicle behavior control apparatus according to the present invention, the vehicle behavior control device further includes notification means for notifying the driver that the first state quantity is matched with the second state quantity (Claim 6).

  According to this aspect, the notification means notifies the driver that the first state quantity and the second state quantity are matched by the state quantity matching means. Therefore, the psychological burden on the driver can be reduced, and the vehicle behavior control is safer.

  Note that the practical aspect of the notification means may be anything as long as it can finally appeal to the five senses of the driver, for example, a sound output means such as a speaker, or a display means such as a display device. Alternatively, a means for controlling these is preferable. For example, the notification means may temporarily use a display or a speaker of a car navigation device. Further, as a simpler form, various MIL (Multi Information Lamp), an indicator, a lamp, or the like arranged in a meter hood or a console panel may be used.

  In another aspect of the vehicle behavior control apparatus according to the present invention, when at least one of the target devices is in an abnormal state when the automatic steering control is switched to the driver steering, the target of the at least one device is As an alternative device to be replaced with at least one of the remaining devices other than the device, there is a state control amount required when the first state quantity and the second state quantity are matched. The automatic steering control execution means continues the automatic steering control by using the selected alternative device (Claim 7).

  According to this aspect, when at least one of the target devices falls into an abnormal state, an alternative device is selected from the remaining devices. When selecting an alternative device, the selection means selects a device having the smallest state control amount required when the first state quantity and the second state quantity are matched. In many cases, the state control amount is different for each apparatus. The “minimum” in such a case may be defined as the minimum index value for comparison standardized with respect to the controllable range of the state control amount.

  Such an apparatus that minimizes the state control amount necessary for making the first state quantity and the second state quantity coincide with each other causes the vehicle state quantity to be controlled by automatic steering control and the apparatus to enter an abnormal state. It is possible to determine in advance experimentally, empirically, or theoretically as a parameter the device that has been used in the automatic steering control that has been executed before.

  If the control amount for matching the first state amount and the second state amount is minimum, the state control that has been changed independently of the driver's steering by the automatic steering control after the steering sovereignty is transferred to the driver The amount of change in the state control amount can be minimized when the amount is returned to the value according to the driver steering and the steering mode is completely switched from the automatic steering control to the driver steering. It becomes possible to relieve the driver's discomfort, discomfort or anxiety during the period.

  In another aspect of the vehicle behavior control device according to the present invention, the at least one device is a front wheel rudder angle changing means capable of changing a front wheel rudder angle, and a rear wheel capable of changing a rear wheel rudder angle. At least one of wheel steering angle variable means, auxiliary steering torque supply means capable of supplying auxiliary steering torque to assist the steering torque of the driver, and braking / driving force difference variable means capable of changing the braking / driving force of the left and right wheels (Claim 8).

  The front wheel rudder angle varying means is a means capable of changing the front wheel rudder angle independently of the driver's steering operation that prompts these changes. The driver's steering operation preferably means an operation of various steering input means such as a steering wheel. Therefore, according to the front wheel rudder angle varying means, it is possible to change the front wheel rudder angle to a desired value even if the driver releases his / her hand from the handle or only holds the handle. is there. The front wheel rudder angle varying means may include VGRS as a suitable form.

  The rear wheel rudder angle varying means is a means capable of changing the rear wheel rudder angle independently of the driver's steering operation that prompts these changes. The driver's steering operation preferably means an operation of various steering input means such as a steering wheel. Therefore, according to the rear wheel rudder angle varying means, the rear wheel rudder angle can be changed to a desired value even if the driver releases his / her hand from the handle or only holds the handle. Is possible. The rear wheel rudder angle varying means may include ARS or the like as a suitable form.

  According to each of these steering angle variable means, the steering angle of the wheel to be controlled by the steering angle is variable at least within a certain range. Therefore, theoretically, the steering direction from the driver or the vehicle behavior can be input from the driver. It becomes possible to control it independently.

  The braking / driving force difference varying means is a means capable of changing the left / right braking / driving force difference of the entire vehicle. Normally, in view of the fact that the wheels to which the braking / driving force is applied are the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel, the braking / driving force difference varying means is a suitable form. It includes at least one of a device capable of changing the left / right braking / driving force difference of the front wheels and a device capable of changing the left / right braking / driving force difference of the rear wheels.

  Further, since the braking force is a negative driving force, both are vehicle state quantities that can be added and subtracted in the same dimension. Therefore, the device capable of changing the left / right braking / driving force difference between the front wheels or the rear wheels is a device capable of changing at least one of the braking force and the driving force of each wheel as a preferred embodiment. means.

  The braking / driving force difference varying means according to the present invention includes, for example, various driving force variable devices including a driving force distribution differential mechanism or an in-wheel motor system, various braking force variable devices including various ECBs, etc. Practical aspects such as both can be taken.

  In any case, when a braking / driving force difference is generated between the left side and the right side of the vehicle, the vehicle is on the side of the wheel having the relatively small driving force (that is, the wheel having the relatively large braking force) (that is, the right wheel). If the driving force (braking force) is small (if it is large), it turns to the right). Therefore, according to the braking / driving force difference varying means, it is theoretically possible to change the traveling direction of the vehicle independently of the driver's steering operation.

  The auxiliary steering torque supply means is means capable of supplying auxiliary steering torque for assisting the driver steering torque given by the driver via the steering wheel, and preferably includes EPS or the like.

  The auxiliary steering torque supply means can supply the auxiliary steering torque independently of the driver's steering because of its configuration. For example, by applying this auxiliary steering torque around the kingpin shaft, the steering direction is applied to the steered wheels. It is also possible to cancel the self-aligning torque acting in the opposite direction. Since the self-aligning torque acts as a steering reaction torque that rotates the steering wheel in a direction opposite to the original steering direction in a situation where the driver does not hold the steering wheel, the auxiliary steering torque also controls the vehicle state quantity. It can be an effective state control amount.

  When the auxiliary steering torque supply means is provided as described above, the auxiliary steering torque is included in two state control amounts among the front wheel steering angle, the rear wheel steering angle, the front wheel left / right braking / driving force difference and the rear wheel left / right braking / driving force difference. Using the three state control variables, for example, three-degree-of-freedom motion control that independently controls three vehicle state variables, such as yaw rate, body slip angle, and steering reaction torque (self-aligning torque). It can also be realized.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

1 is a schematic configuration diagram conceptually illustrating a configuration of a vehicle according to an embodiment of the present invention. It is a control block diagram of ECU which concerns on vehicle motion control based on a vehicle motion model. It is a schematic diagram concerning the definition of the model variable of a vehicle movement model. It is a schematic diagram concerning the definition of other model variables of a vehicle movement model. It is a schematic diagram which concerns on the definition of the further another model variable of a vehicle motion model. 2 is a flowchart of automatic steering control performed in the vehicle of FIG. 1. It is a flowchart of the transfer preparation process in the automatic steering control of FIG. FIG. 8 is a diagram conceptually showing the motion state of the vehicle in relation to the effect of the transfer preparation process of FIG. 7. FIG. 8 is a diagram conceptually showing another motion state of the vehicle in relation to the effect of the transfer preparation process of FIG. 7.

Hereinafter, an embodiment according to a vehicle behavior control apparatus of the present invention will be described with reference to the drawings as appropriate.
<Embodiment of the Invention>
<Configuration of Embodiment>
First, with reference to FIG. 1, the structure of the vehicle 10 which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a schematic configuration diagram conceptually showing the basic configuration of the vehicle 10.

  In FIG. 1, a vehicle 10 includes a left front wheel FL and a right front wheel FR as front wheels, which are steered wheels (meaning wheels connected to a handle 12 described later), and a left rear wheel RL and a right rear wheel as rear wheels. A wheel RR is provided, and the vehicle can travel in a desired direction by changing the steering angle of the front and rear wheels.

  The vehicle 10 includes an ECU 100, an engine 200, a TRC (TRaction Control System; driving force distribution device) 300, a VGRS actuator 400, an EPS actuator 500, an ECB 600, a car navigation device 700, and an ARS actuator 800.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory) (not shown) and is configured to be able to control the entire operation of the vehicle 10. 1 is an example of a “vehicle behavior control device”. The ECU 100 is configured to execute vehicle behavior control, which will be described later, according to a control program stored in the ROM.

  The ECU 100 is configured to function as an example of each of “automatic steering control execution means”, “handle angle detection means”, “state quantity matching means”, “notification means”, and “selection means” according to the present invention. The integrated electronic control unit is configured such that all the operations related to these means are executed by the ECU 100. However, the physical, mechanical, and electrical configurations of each of the units according to the present invention are not limited to this. For example, each of these units includes a plurality of ECUs, various processing units, various controllers, a microcomputer device, and the like. It may be configured as various computer systems.

  The engine 200 is a power source of the vehicle 10.

  The power source of the vehicle according to the present invention is an internal combustion engine (engine 200) having various practical aspects as a concept encompassing an engine that can convert thermal energy accompanying combustion of fuel into mechanical power (kinetic energy) and take it out. Is also an example thereof, and may be a rotating electrical machine such as a motor. Alternatively, the vehicle may be a so-called hybrid vehicle in which these are cooperatively controlled. A crankshaft as a driving force output shaft of the engine 200 is connected to a center differential device 310 which is a component of the TRC 300. It should be noted that the detailed configuration of the engine 200 has little correlation with the gist of the present invention, and therefore the details are omitted here.

  The TRC 300 is configured to be able to distribute the engine torque Te transmitted from the engine 200 via the crankshaft to the front wheels and the rear wheels at a predetermined ratio, and further, drives the left and right wheels in each of the front wheels and the rear wheels. This is a driving force distribution device as an example of the “braking / driving force difference varying means” according to the present invention, which is configured to be able to change the force distribution.

  The TRC 300 includes a center differential device 310 (hereinafter referred to as “center differential 310” as appropriate), a front differential device 320 (hereinafter referred to as “front differential 320” as appropriate) and a rear differential device 330 (hereinafter referred to as “rear differential 330 as appropriate”). ").

  Center differential 310 is an LSD (Limited Slip Differential) that distributes engine torque Te supplied from engine 200 to front differential 320 and rear differential 330.

  The center differential 310 distributes the engine torque Te to the front and rear wheels at a distribution ratio of 50:50 (one example is not particularly limited) under a condition where the load acting on the front and rear wheels is substantially constant. Further, when the rotational speed of one of the front and rear wheels becomes higher than a predetermined value with respect to the other, a differential limiting torque is applied to the one, and a differential limiting is performed in which torque is transferred to the other. . That is, the center differential 310 is a so-called rotational speed-sensitive (viscous coupling type) differential mechanism.

  The center differential 310 is not limited to such a rotational speed sensitive type, but may be a torque sensitive type differential mechanism in which the differential limiting action increases in proportion to the input torque. Also, a differential ratio variable type differential that can achieve a desired distribution ratio within a predetermined adjustment range by making a differential action by the planetary gear mechanism and continuously changing the differential limiting torque by the intermittent control of the electromagnetic clutch. It may be a mechanism. In any case, the center differential 310 may take various practical aspects regardless of whether it is publicly known or not known as long as the engine torque Te can be distributed to the front wheels and the rear wheels.

  The front differential 320 can distribute the engine torque Te distributed to the front axle (front wheel axle) side by the center differential 310 further to the left and right wheels at a desired distribution ratio set within a predetermined adjustment range. A type of LSD.

  The front differential 320 includes a planetary gear mechanism including a ring gear, a sun gear, and a pinion carrier, and an electromagnetic clutch that provides a differential limiting torque. A differential case is provided for the ring gear of the planetary gear mechanism, and left and right axles are provided for the sun gear and the carrier, respectively. Takes a linked configuration. The differential limiting torque is continuously controlled by energization control on the electromagnetic clutch, and the torque distribution ratio is continuously variably controlled within a predetermined adjustment range determined by the physical and electrical configuration of the front differential 320. It is the composition which becomes.

The front differential 320 is electrically connected to the ECU 100, and the energization control of the electromagnetic clutch is also controlled by the ECU 100. Therefore, the ECU 100 can generate a desired front wheel left / right braking / driving force difference (here, the driving force difference) F _f through the drive control of the front differential 320.

  The configuration of the front differential 320 is limited to that exemplified here as long as the driving force (note that the torque and the driving force are uniquely related) can be distributed to the left and right wheels at a desired distribution ratio. It can have various aspects regardless of whether it is publicly known or not known. In any case, such a right / left driving force distribution action is known, and here, the details thereof will not be mentioned for the purpose of preventing the explanation from becoming complicated.

  The rear differential 330 distributes the engine torque Te distributed to the rear axle (rear axle) via the propeller shaft 11 by the center differential 310, and further at a desired distribution ratio set within a predetermined adjustment range for the left and right wheels. This is a variable distribution ratio LSD that can be distributed.

  The rear differential 330 includes a planetary gear mechanism including a ring gear, a sun gear, and a pinion carrier, and an electromagnetic clutch that provides differential limiting torque. A differential case is connected to the ring gear of the planetary gear mechanism, and left and right axles are connected to the sun gear and the carrier, respectively. Adopted configuration. The differential limiting torque is continuously controlled by energization control for the electromagnetic clutch, and the torque distribution ratio is continuously variably controlled within a predetermined adjustment range determined by the physical and electrical configuration of the rear differential 330. It has a configuration.

The rear differential 330 is electrically connected to the ECU 100, and the energization control of the electromagnetic clutch is also controlled by the ECU 100. Therefore, ECU 100, via the drive control of the rear differential 330, (here, a is the driving force difference) desired rear wheel left and right longitudinal force difference it is possible to cause F _r.

  The configuration of the rear differential 330 is limited to that illustrated here as long as the driving force (where torque and driving force are uniquely related) can be distributed to the left and right wheels at a desired distribution ratio. It can have various aspects regardless of whether it is publicly known or not. In any case, such a right / left driving force distribution action is known, and here, the details thereof will not be mentioned for the purpose of preventing the explanation from becoming complicated.

  The VGRS actuator 400 is a steering transmission ratio variable device including a housing, a VGRS motor, a speed reduction mechanism, a lock mechanism (all not shown), and the like, and is an example of the “front wheel steering angle variable means” according to the present invention.

  In the VGRS actuator 400, the VGRS motor, the speed reduction mechanism, and the lock mechanism are accommodated in a housing. This housing is fixed to the downstream end portion of the upper steering shaft 13 connected to the handle 12 as a steering input means, and is configured to be able to rotate substantially integrally with the upper steering shaft 13.

  The VGRS motor is a DC brushless motor having a rotor as a rotor, a stator as a stator, and a rotation shaft as an output shaft of driving force. The stator is fixed inside the housing, and the rotor is rotatably held inside the housing. The rotating shaft is fixed so as to be coaxially rotatable with the rotor, and the downstream end thereof is connected to the speed reduction mechanism. The stator is configured to be supplied with a drive voltage from an electric drive circuit (not shown).

  The speed reduction mechanism is a planetary gear mechanism having a plurality of rotational elements capable of differential rotation. One rotation element of the plurality of rotation elements is connected to the rotation shaft of the VGRS motor, and one of the other rotation elements is connected to the housing. The remaining rotating elements are connected to the lower steering shaft 14.

  According to the speed reduction mechanism having such a configuration, the rotation speed of the upper steering shaft 13 (that is, the rotation speed of the housing) corresponding to the operation amount of the handle 12 and the rotation speed of the VGRS motor (that is, the rotation speed of the rotation shaft). ) Uniquely determines the rotation speed of the lower steering shaft 14 connected to the remaining one rotation element. At this time, the rotational speed of the lower steering shaft 14 can be controlled to increase / decrease by controlling the rotational speed of the VGRS motor to increase / decrease by the differential action between the rotating elements. That is, the upper steering shaft 13 and the lower steering shaft 14 can be rotated relative to each other by the action of the VGRS motor and the speed reduction mechanism. The rotational speed of the VGRS motor is transmitted to the lower steering shaft 14 in a state of being decelerated in accordance with a predetermined reduction ratio determined according to the gear ratio between the respective rotary elements because of the configuration of each rotary element in the speed reduction mechanism.

Thus, in the vehicle 10, the upper steering shaft 13 and the lower steering shaft 14 can rotate relative to each other, so that the steering angle δ _{h that} is the rotation amount of the upper steering shaft 13 and the rotation amount of the lower steering shaft 14 are determined. Thus, the steering transmission ratio, which is uniquely determined (which also relates to the gear ratio of a rack and pinion mechanism described later) and the front wheel steering angle δ _f as a steering wheel, is continuously variable within a predetermined range.

  The lock mechanism is a clutch mechanism including a clutch element on the VGRS motor side and a clutch element on the housing side. In a state where both clutch elements are engaged with each other, the rotational speeds of the upper steering shaft 13 and the rotation shaft of the VGRS motor coincide with each other, so that the rotational speed of the lower steering shaft 14 necessarily coincides therewith. That is, the upper steering shaft 13 and the lower steering shaft 14 are directly connected. However, the details of the locking mechanism are omitted here because the correlation with the present invention is weak.

  Note that the VGRS actuator 400 is electrically connected to the ECU 100 and its operation is controlled by the ECU 100.

  In the vehicle 10, the rotation of the lower steering shaft 14 is transmitted to the rack and pinion mechanism. The rack and pinion mechanism is a steering transmission mechanism including a pinion gear (not shown) connected to the downstream end of the lower steering shaft 14 and a rack bar 15 formed with gear teeth that mesh with gear teeth of the pinion gear. The rotation of the pinion gear is converted into the horizontal movement of the rack bar 15 in the drawing, so that the steering force is applied to each steered wheel via a tie rod and a knuckle (not shown) connected to both ends of the rack bar 15. It is configured to be transmitted.

  The EPS actuator 500 includes an EPS motor as a DC brushless motor including a rotor (not shown) that is a rotor with a permanent magnet and a stator that is a stator that surrounds the rotor. This is an electronically controlled power steering device as an example of the “steering torque supply means”.

This EPS motor can generate EPS torque T _eps in its rotating direction by rotating the rotor by the action of a rotating magnetic field formed in the EPS motor by energizing the stator via an electric drive (not shown). It is configured.

On the other hand, a reduction gear (not shown) is fixed to the motor shaft which is the rotation shaft of the EPS motor, and this reduction gear meshes directly or indirectly with the reduction gear provided on the lower steering shaft 14. ing. For this reason, in the present embodiment, the EPS torque T _{eps generated} from the EPS motor functions as a torque that assists the rotation of the lower steering shaft 14. Therefore, when the EPS torque T _eps is applied in the same direction as the driver steering torque MT applied to the upper steering shaft 13 via the handle 12, the driver's steering burden is reduced by the EPS torque T _eps. Is done.

  The EPS actuator 500 is a so-called electronically controlled power steering device that is electrically connected to the ECU 100 and whose operation is controlled by the ECU 100. The power steering device provided in the vehicle 10 is a hydraulic power steering device. May be.

  The vehicle 10 includes a handle angle sensor 16 and a steering torque sensor 17.

The handle angle sensor 16 is an angle sensor configured to be able to detect a handle angle δ _h representing the rotation amount of the upper steering shaft 13. Steering wheel angle sensor 16 is connected to ECU 100 and electrically, the detected steering wheel angle [delta] _h has become structure as referenced in constant or irregular period by the ECU 100.

  The steering torque sensor 17 is a sensor configured to be able to detect a driver steering torque MT applied from the driver via the handle 12. More specifically, the upper steering shaft 13 is divided into an upstream portion and a downstream portion, and has a configuration in which they are connected to each other by a torsion bar (not shown). Rings for detecting a rotational phase difference are fixed to both upstream and downstream ends of the torsion bar. The torsion bar is twisted in the rotational direction in accordance with a steering torque (that is, driver steering torque MT) transmitted through the upstream portion of the upper steering shaft 13 when the driver of the vehicle 10 operates the handle 12. Thus, the steering torque can be transmitted to the downstream portion while causing such a twist. Therefore, when the steering torque is transmitted, a rotational phase difference is generated between the above-described rings for detecting the rotational phase difference. The steering torque sensor 17 is configured to detect such a rotational phase difference and convert the rotational phase difference into a steering torque so as to be output as an electrical signal corresponding to the driver steering torque MT. The steering torque sensor 17 is electrically connected to the ECU 100, and the detected driver steering torque MT is referred to by the ECU 100 at a constant or indefinite period.

  The steering torque detection method is not limited to this type of torsion bar method, and other methods may be employed.

  The ECB 600 is an electronically controlled braking device as another example of the “braking / braking force difference varying means” according to the present invention, which is configured to be able to individually apply a braking force to the front, rear, left, and right wheels of the vehicle 10. The ECB 600 includes a brake actuator 610 and braking devices 620FL, 620FR, 620RL, and 620RR corresponding to the left front wheel FL, the right front wheel FR, the left rear wheel RL, and the right rear wheel RR, respectively.

  The brake actuator 610 is a hydraulic control actuator configured to be able to individually supply hydraulic oil to the braking devices 620FL, 620FR, 620RL, and 620RR. The brake actuator 610 includes a master cylinder, an electric oil pump, a plurality of hydraulic pressure transmission passages, and electromagnetic valves installed in each of the hydraulic pressure transmission passages. The brake actuator 610 controls each brake by controlling the open / close state of the electromagnetic valves. The hydraulic pressure of the hydraulic oil supplied to the wheel cylinder provided in the device is configured to be individually controllable for each braking device. The hydraulic pressure of the hydraulic oil has a one-to-one relationship with the pressing force of the brake pad provided in each brake device, and the hydraulic oil pressure level of the hydraulic oil corresponds to the magnitude of the braking force in each brake device.

  The brake actuator 610 is electrically connected to the ECU 100, and the braking force applied to each wheel from each braking device is controlled by the ECU 100.

  The vehicle 10 further includes an in-vehicle camera 18 and a vehicle speed sensor 19.

  The in-vehicle camera 18 is an imaging device that is installed on the front nose of the vehicle 10 and configured to image a predetermined area in front of the vehicle. The in-vehicle camera 18 is electrically connected to the ECU 100, and the captured front area is sent to the ECU 100 as image data at a constant or indefinite period. The ECU 100 can analyze the image data and acquire various data necessary for LKA control described later.

  The vehicle speed sensor 19 is a sensor configured to be able to detect the vehicle speed V as the speed of the vehicle 10. The vehicle speed sensor 19 is electrically connected to the ECU 100, and the detected vehicle speed V is referred to by the ECU 100 at a constant or indefinite period.

  Instead of the vehicle speed sensor 19, the ECU 100 may calculate the vehicle speed from a wheel speed sensor attached to each wheel.

  The car navigation device 700 is based on signals acquired via a GPS antenna and a VICS antenna installed in the vehicle 10, position information of the vehicle 10, road information around the vehicle 10 (road type, road width, number of lanes). , Speed limit, road shape, etc.), traffic signal information, information on various facilities installed around the vehicle 10, traffic information including traffic information, environment information, and the like. The car navigation device 700 is electrically connected to the ECU 100, and the operation state is controlled by the ECU 100.

The ARS actuator 800 can change the rear wheel steering angle δ _r which is the steering angle of the left rear wheel RL and the right rear wheel RR independently of the steering input given by the driver via the handle 12. It is a rear-wheel steering actuator which is an example of the “rear wheel steering angle varying means” according to the invention.

The ARS actuator 800 includes an ARS motor and a reduction gear mechanism, and a drive circuit for the ARS motor is electrically connected to the ECU 100. Therefore, the ECU 100 can control the ARS torque _Tars , which is the output torque of the ARS motor, by controlling the drive circuit.

  On the other hand, the reduction gear is configured to be able to transmit the torque of the ARS motor to the rear steer rod 20 with deceleration.

Rear steering rod 20, and a left rear wheel RL and the right rear wheel RR, are connected via the respective joint members 21RL and 21RR, the rear steering rod 20 is driven to the illustrated right direction by ARS torque _{T ars,} each The rear wheels are steered in one direction.

  The ARS actuator 800 may include a linear motion mechanism that can convert a rotational motion into a stroke motion. When this type of linear motion mechanism is provided, the rear steer rod 20 may change the rudder angle of the rear wheels in accordance with the left-right stroke motion of the linear motion mechanism.

The practical aspect of the rear wheel steering device is not limited to that of the illustrated ARS actuator 800 as long as the rear wheel steering angle δ _r can be varied within a predetermined range.

The vehicle 10 according to the present embodiment includes the TRC 300, the VGRS actuator 400, the EPS actuator 500, the ECB 600, and the ARS actuator 800 as “at least one device” according to the present invention. It is only an example of a configuration that the vehicle according to the invention can take. For example, the vehicle may include only a part of these.
<Operation of Embodiment>
Next, the operation of this embodiment will be described.

<Outline of automatic steering control based on vehicle motion model>
First, automatic steering control based on a vehicle motion model will be described with reference to FIG. FIG. 2 is a control block diagram of the ECU 100 related to automatic steering control. The automatic steering control is one type of vehicle motion control based on a vehicle motion model that is executed in vehicle behavior control described later, and is an example of “automatic steering control” according to the present invention.

  In FIG. 2, the target state amount calculation unit 110, the state control amount calculation unit 120, and the abnormality detection unit 130 are components of the ECU 100.

In vehicle motion control based on a vehicle motion model including automatic steering control described later, a target state amount calculation unit 110 calculates a target state amount of the vehicle 10. The target state quantity is a target value of the vehicle state quantity. In automatic steering control, follow-up travel to the target travel path is realized by independent control of the vehicle body slip angle β and yaw rate γ as vehicle state quantities, and the steering reaction torque T _sat is controlled independently of these. .

  Here, the ECU 100 first calculates a target state quantity under various known methods based on image data sent from the in-vehicle camera 18, road surface data or position data sent from the car navigation device 700, or the like. Calculate basic information to do. For example, at this time, a lateral deviation Y that is a lateral deviation between the target body (for example, a white line) and the vehicle 10, a yaw angle deviation φ between the target body and the vehicle 10, and the like are calculated.

Based on the basic information, the target state quantity calculation unit 110 uses the target yaw rate γ _tg , the target vehicle body slip angle β _tg, and the target value as target values of the vehicle state quantity required to cause the vehicle 10 to follow the target travel path. Steering reaction force torque T _sattg is calculated.

Of these target state quantities, the target vehicle body slip angle β _tg and the target yaw rate γ _tg are stored in advance in appropriate storage means such as a ROM in the basic information (here, the lateral deviation Y and the yaw angle deviation φ). It is mapped and stored in a form that is associated with it. Further, the target steering reaction torque T _satgtg is basically set to zero.

Note that the target steering reaction force torque T _sattg being zero means that no steering reaction force is returned to the handle 12, which means that it is possible to let go. However, the target steering reaction torque T _satgtg does not necessarily have to be zero, and may be appropriately set so as to artificially give an appropriate steering reaction force to the driver.

  Each target state quantity set by the target state quantity computing unit 110 is sent to the state control quantity computing unit 120. The state control amount calculation unit 120 is an arithmetic processing device that replaces each set target state amount with a target value of an actual state control amount corresponding to each vehicle state amount control device.

More specifically, the state control amount calculation unit 120, EPS torque _{T eps,} front wheel steering angle [delta] _f and a rear wheel steering angle [delta] _r, respectively corresponding target EPS torque _{T Epstg,} the target front wheel steering angle [delta] _FTG and after the target The wheel steering angle δ _rtg is set. The state control amount calculation unit 120 sets a target value of the state control amount based on a known vehicle motion model.

Here, since there are three vehicle state quantities to be controlled by the automatic steering control, there are also three state control quantities necessary for establishing the vehicle motion model. Therefore, in the present embodiment, the target left / right braking / driving force difference F _{xtg which} is the target value of the left / right braking / driving force difference F _x (F _x = F _f + F _r ) is _normally set to zero. That is, in the automatic steering control, the vehicle body slip angle β and the yaw rate γ are normally controlled by the steering angle control of the front and rear wheels. However, the left / right braking / driving force difference between the front and rear wheels may be used instead of one of the front and rear wheel steering angles.

When the target value of each state control amount is calculated by the state control amount calculation unit 120, a control signal corresponding to each target value is supplied to the vehicle state amount control device corresponding to each state control amount. That, EPS actuator 500 if the target EPS torque _{T Epstg,} if the target front wheel steering angle [delta] _FTG VGRS actuator 400, if target rear wheel steering angle [delta] _rtg ARS actuator 800, the left and right longitudinal force difference _{F x} (or If the front wheel left / right braking / driving force difference F _f or the rear wheel left / right braking / driving force difference F _r ), a control signal is supplied to the ECB 600 or TRC 300. As a result, the vehicle state quantities (β, γ, and T _sat ) are maintained at the target values due to actual changes in the state control quantities, and the vehicle behavior is maintained at the target behavior.

  On the other hand, the abnormality detection unit 130 performs a determination process as to whether or not the VGRS actuator 400 and the ARS actuator 800 are in an abnormal state at regular intervals during the execution period of the automatic steering control.

  At this time, the abnormality detection unit 130 monitors the control amounts (driving voltage and driving current) for driving each actuator, and enters an abnormal state when they are not in the normal range experimentally given in advance. It is configured to set an abnormality determination flag indicating that there is. In addition, the abnormality detection unit 130 acquires the motor temperature of each actuator from a temperature sensor attached to each motor, and determines whether or not these are in an abnormal state based on the acquired motor temperature of each actuator. It is the composition which performs. More specifically, when the motor temperature related to each motor exceeds a reference temperature experimentally given in advance, the previous abnormality determination flag is set as a high heat load. .

<Details of vehicle motion model>
Here, the details of the vehicle motion model will be described. Each model variable used in the vehicle motion model according to the present embodiment is as follows.

s ... Laplace operator δ _f ... Front wheel steering angle δ _r ... Rear wheel steering angle β ... Car body slip angle γ ... Yaw rate T _sat ... Steering reaction torque (in this embodiment) , Self-aligning torque)
τ _eps・ ・ ・ EPS torque around the kingpin axis m ・ ・ ・ Vehicle weight I ・ ・ ・ Yaw moment of inertia l ・ ・ ・ Wheel base l _f・ ・ ・ Front-rear distance from vehicle center of gravity to front axis l _r・ ・ ・ Vehicle Front-rear direction distance from the center of gravity to the rear axle K _f ... Front wheel cornering force K _r ... Rear wheel cornering force t _f ... Front tread _tr ... Rear tread l _t ... Castor rail + pneumatic Trail l _k・ ・ ・ Kingpin offset Y _f・ ・ ・ Front wheel lateral force Y _r・ ・ ・ Rear wheel lateral force F _fl・ ・ ・ Left front wheel driving force F _fr・ ・ ・ Right front wheel driving force F _rl・ ・ ・ Left rear Wheel drive force _Frr ... Right rear wheel drive force _Ff ... Front wheel left / right braking / driving force difference _Fr ... Rear wheel left / right braking / driving force difference Here, refer to FIGS. Visualize each model variable above Explain. FIG. 3 is a schematic diagram relating to the definition of the model variable of the vehicle motion model. FIG. 4 is a schematic diagram relating to the definition of other model variables of the vehicle motion model. Further, FIG. 5 is a schematic diagram relating to the definition of still another model variable of the vehicle motion model.

3, the longitudinal direction tangent vehicle, the angle between the longitudinal direction tangent of the front wheel, a front wheel steering angle [delta] _f. Similarly, the longitudinal direction tangent vehicle, the angle between the longitudinal direction tangent to the rear wheels, a rear wheel steering angle [delta] _r.

  On the other hand, the angle formed between the speed direction of the vehicle 10 (the direction of the vehicle speed V shown in the figure) and the tangent to the vehicle longitudinal direction is the vehicle body slip angle β. The vehicle body slip angle β is an angle generated when the vehicle 10 turns due to a yaw moment I generated around the center of gravity G due to a change in the steering angle of the front and rear wheels.

  FIG. 4 shows the balance of torque around the kingpin axis in the left front wheel FL.

If lateral force to the tire ground contact point C Y _f and the front wheel driving force difference F _f is acting, the front left wheel FL, a self-aligning torque is generated in the direction to cancel the change the steering angle. This self-aligning torque becomes a steering reaction torque T _sat that tries to move the handle 12 in the direction opposite to the steering direction.

The torque for canceling the steering reaction torque T _sat is obtained by converting the EPS torque into a torque around the virtual grounding point KP of the kingpin shaft (which is a virtual steering axis connecting the upper pole joint and the lower pole joint). a surrounding EPS torque tau _eps, by acting on the kingpin axis to illustrate this kingpin axis EPS torque tau _eps, steering reaction force torque _{T sat} is canceled.

FIG. 5 shows a left front wheel driving force F _fl on the left front wheel FL, a right front wheel driving force F _fr on the right front wheel FR, a left rear wheel driving force F _{rl on} the left rear wheel RL, and a right rear wheel driving force on the right rear wheel RR. It shows how F _rr is acting. In addition, although driving force was illustrated here, it is the same also about braking force only by the direction of action becoming reverse (downward in the figure).

In this case, a relationship of F _f = F _fr −F _fl is established between each driving force acting on the front wheel and the front wheel left / right braking / driving force difference F _f . Similarly, a relationship of F _r = F _rr −F _rl is established between each driving force acting on the rear wheel and the rear wheel left / right braking / driving force difference F _r .

The distance between the left and right front wheels of the ground point is a front wheel tread t _f, the distance between the ground point of the left and right rear wheels are the rear wheels tread t _r.

  Next, actual operation of the vehicle motion model using these model variables will be described.

  The relationship between the vehicle body slip angle β, the yaw rate γ, the steering reaction torque Tsat, the front wheel steering angle δf, the rear wheel steering angle δr, and the EPS torque τeps around the kingpin axis is expressed by the following equation (1). It is defined as follows.

  Here, A in the above equation (1) is a matrix defined by the following equation (2), and B is a matrix defined by the following equation (3).

From the above equation (1), the front wheel steering angle δ _f , the rear wheel steering angle δ _r and the EPS torque τ _eps about the kingpin axis for realizing the vehicle body slip angle β, the yaw rate γ, and the steering reaction force torque T _sat are finally determined. Is expressed by the following equation (4). B- ¹ is an inverse matrix of the matrix B.

In the automatic steering control, the state control amount calculation unit 120 controls the state of the target state amounts (β _tg , γ _tg and T _sattg ) calculated by the target state amount calculation unit 110 based on the above equation (4). It is the structure which calculates the target value ((delta _{) ftg} , (delta _{) rtg,} and (tau) _epstg ) of _quantity . It is assumed that the operation logic for converting the EPS torque τ _eps about the kingpin axis into the EPS torque T _eps is held in advance by the state control amount calculator 120.
<Details of vehicle behavior control>
Next, the details of the vehicle behavior control will be described with reference to FIG. FIG. 6 is a flowchart of the vehicle behavior control.

  In FIG. 6, the ECU 100 reads various signals including operation signals of various switches provided in the vehicle 10, various flags, sensor signals related to the various sensors, and the like, and selects an automatic steering control previously installed in the vehicle interior of the vehicle 10. It is determined whether or not execution of automatic steering control is requested as a result of the operation button being operated by the driver (step S101). When the automatic steering control is not requested (step S101: NO), the ECU 100 returns the process to step S101.

  When the automatic steering control is selected (step S101: YES), the ECU 100 starts the automatic steering control based on the vehicle motion model described above (step S102). When the automatic steering control is started, the ECU 100 determines whether or not an automatic steering control end condition is satisfied (step S103), and continues the automatic steering control unless the end condition is satisfied (step S103: NO). To do.

  In addition, the termination conditions of automatic steering control are various, and are not limited uniquely. For example, the automatic steering control is terminated when the driver performs an operation requesting the termination of the automatic steering control via the operation button described above. Further, the process is terminated when the driver applies an appropriate driver steering torque to the handle 12 (that is, when an override operation is performed). Alternatively, the process is terminated when the abnormality detection unit 130 described above detects an abnormality in the VGRS actuator 400 or the ARS actuator 800 used for automatic steering control.

  When the automatic steering control termination condition is satisfied (step S103: YES), the ECU 100 executes a transfer preparation process (step S200).

Here, the transfer preparation process is a process to alleviate the driver's uncomfortable feeling that occurs immediately after the steering sovereignty is transferred to the driver in the transition period of the steering mode switching from automatic steering control to driver steering. is a control target of the automatic steering control and one vehicle state amount correlating with the steering wheel angle [delta] _h (here, assumed to be the yaw rate gamma) for the first yaw rate (i.e. generated by the automatic steering control, the present invention and an example of the "first state quantity") of the actual second yaw rate should occur with respect to the steering wheel angle [delta] _h (i.e., is the process of matching an example) and according to the present invention, "the second state amount" .

  Here, the details of the transfer preparation process will be described with reference to FIG. FIG. 7 is a flowchart of the transfer preparation process.

In FIG. 7, the ECU 100 first reads a target value of a vehicle state quantity to be controlled by automatic steering control, that is, a target vehicle body slip angle β _tg and a target yaw rate γ _tg (step S201). When each target value is read, ECU 100 calculates the required steering wheel angle δ _htg at the time of transfer based on the read target yaw rate γ _tg (step S202).

The necessary steering wheel angle δ _htg at the time of transfer is necessary for generating the target yaw rate γ _tg (first yaw rate) of the automatic steering control at that time in driver steering which is a normal steering mode reflecting the driver's steering intention. Is the handle angle.

If the steering wheel angle is controlled to the required steering wheel angle δ _htg at the time of transfer corresponding to the first yaw rate, the second yaw rate that should be generated according to the steering wheel angle inevitably matches the first yaw rate. That is, the control for realizing the necessary handle angle δ _htg at the time of transfer is an example of the control for “matching the second state quantity with the first state quantity” according to the present invention.

After calculating the necessary handle angle δ _htg at the time of transfer, the ECU 100 determines whether or not an abnormality of the VGRS actuator 400 or the ARS actuator 800 is detected by the abnormality detection unit 130 (step S203).

  When at least one of these actuators used for automatic steering control is in an abnormal state (step S203: YES), ECU 100 is the remaining device that is not used at that time among devices that can be used for vehicle state quantity control. In other words, an alternative device is selected from the TRC 300 or the ECB 600 (step S204).

Since both the TRC 300 and the ECB 600 are devices that can generate a front wheel left / right braking / driving force difference F _f and a rear wheel left / right braking / driving force F _r , when one of the actuators is in an abnormal state, which one is selected. Also good. However, as to which of the front wheel left / right braking / driving force difference _Ff and the rear wheel left / right braking / driving force difference _Fr is used as an alternative state control amount, the state control amount required for vehicle state amount matching described later is determined. The one that is the smallest is selected. Information on the device that minimizes the state control amount required for matching the vehicle state amount is determined in advance according to the type of state control amount to be controlled by the automatic steering control and the combination of devices to be used. It is determined experimentally, empirically or theoretically, and is stored as control information in the ROM.

When the alternative device is selected or when it is determined in step S203 that none of the actuators is in an abnormal state (step S203: NO), the ECU 100 determines the target vehicle state quantity (β _tg , γ related to automatic steering control). _tg and T _sattg ) and a control amount for realizing the transfer necessary handle angle δ _htg are calculated (step S205).

When the control amount is calculated, the vehicle state amount (here, yaw rate γ) is matched (step S206). That is, the steering wheel angle δ _h is controlled toward the target steering angle δ _htg required for transfer. The matching of the vehicle state quantities will be described in detail later with reference to FIGS. 8 and 9 with visual effects.

  When the matching of the vehicle state quantities is started, the ECU 100 notifies the driver that the matching of the vehicle state quantities has been started (step S207). When the notification to the driver is made, the transfer preparation process ends.

  In this notification, for example, text information such as “The steering wheel angle is being adjusted to end the automatic steering control” is displayed on the information display provided in the car navigation device 700, and the “speaker operation” This may be done by outputting audio information such as "Please prepare for". Alternatively, this notification may be performed simply by lighting a MIL (Multi Information Lamp) attached to a meter panel or the like.

Returning to FIG. 6, the transfer preparation processing is completed, ECU 100, the absolute value of the steering wheel angle deviation .DELTA..delta _h is equal to or less than a preset reference value A (step S104). The handle angle deviation Δδ _h is a deviation between the handle angle δ _htg required at the time of transfer and the actual handle angle δh.

If the absolute value of the steering wheel angle deviation .DELTA..delta _h is equal to or larger than the reference value A (step S104: NO), ECU 100 executes the transfer preparation process again, until the handle angle deviation .DELTA..delta _h is less than the reference value A, transfer preparation Repeat the process.

On the other hand, the steering wheel angle deviation .DELTA..delta _h is the reduced to less than the reference value A (step S104: YES), ECU 100 ends the automatic steering control, to transfer steering sovereignty (steering right) to the driver (Step S105) . When the steering sovereignty is transferred to the driver, the steering mode is switched to driver steering, and the process returns to step S101. The vehicle behavior control is executed in this way.

The reference value A is an adaptation value that is determined in advance so that the difference between the first yaw rate and the second yaw rate does not appear as a great sense of discomfort for the driver. By steering wheel angle deviation Δδ absolute value only if it is more than the reference value A vehicle state quantity of coincidence of in the step S206 of _h can be achieved, discomfort during steering sovereign transfer, the occurrence of discomfort or uneasiness Wasteful consumption of energy resources is prevented while reliably avoiding.

  Here, the effect of the transfer preparation process will be described with reference to FIGS. 8 and 9. FIG. 8 is a diagram conceptually showing the motion state of the vehicle 10 in relation to the effect of the transfer preparation process. FIG. 9 is a diagram conceptually showing another motion state of the vehicle 10 in relation to the effect of the transfer preparation process. In these drawings, the same reference numerals are given to portions overlapping with the above-mentioned drawings, and the description thereof will be omitted as appropriate.

FIG. 8 shows that the yaw rate γ of the vehicle 10 is maintained at the target value via the control of the front wheel steering angle δ _f using the VGRS actuator 400 as the automatic steering control in order to make the effect of the transfer preparation process easy to understand. The case where control is being executed is shown.

The VGRS actuator 400 is an actuator that relatively rotates the upper steering shaft 13 and the lower steering shaft 14 as described above, and is based on the assumption that a torque that is large enough to resist the steering reaction torque T _sat is originally supplied. Not in. Therefore, if an attempt is changed toward the front wheel steering angle [delta] _f to the target value, in practice phenomenon handle 12 is steered in the opposite direction by the steering reaction force torque T _sat may occur. In view of this point, although the control is only for the yaw rate γ, the control for canceling the steering reaction torque by the EPS torque τ _eps about the kingpin axis is executed. That is, strictly speaking, FIG. 8 shows a motion state related to two-degree-of-freedom automatic steering control in which the yaw rate γ and the steering reaction torque T _sat are controlled independently.

FIG. 8A shows a state in which a steering wheel angle δ _h = 0 and a non-zero front wheel steering angle δ _f is given. In this state, the yaw rate γ is generated in the vehicle 10 in the direction indicated by the arrow. Since the automatic steering control is originally independent of the driver's steering intention, even if the yaw rate γ occurs in the state where the steering wheel angle δ _h = 0, there is no problem in terms of the driver's sense.

However, when results in transfer of the steering sovereign driver in the state of FIG. 8 (a), the despite the steering wheel angle [delta] _h of the handle 12 that the driver steering hold itself intention is zero, the vehicle 10 is yaw Since the person is exercising, the driver feels a sense of discomfort, discomfort or anxiety.

This uncomfortable feeling is caused by the second yaw rate (that is, zero) that should be generated for the steering wheel angle δ _h (δ _h = 0) at this time in the driver steering control and the first yaw rate that is generated at this time by the automatic steering control ( This is because the non-zero yaw rate corresponding to the arrow shown in the figure does not match.

Therefore, in step S205 (control amount calculation) in the transfer preparation process, the required handle angle δ _htg at the time of transfer corresponding to the yaw rate corresponding to the illustrated arrow is calculated, and the handle angle δ _h is calculated as the calculated transfer. A front wheel rudder angle δ _f that maintains the yaw rate corresponding to the arrow shown in the figure as a target state quantity while being converged to the required steering wheel angle δ _htg is calculated.

Subsequently, in step S206 (the state quantity coincides reduction) defining, on the basis of the calculated control amount, appropriate device is driven and controlled, the steering wheel angle [delta] _h is the time of transfer required wheel angle [delta] _HTG and the reference value A It is converged within the allowable range. This state is shown in FIG.

  FIG. 8B shows a state in which the handle 12 is steered in the right turn direction and the vehicle 10 is generating a yaw rate in the right turn direction. When the steering sovereignty is transferred to the driver in this state, the driver does not feel uncomfortable, uncomfortable or uneasy. That is, a decrease in drivability is prevented.

In the vehicle motion of FIG. 8, when the vehicle state is shifted from the state of FIG. 8A to the state of FIG. 8B, the VGRS actuator 400 requires a control amount (handle angle δ) required for automatic steering control. The relative rotation amount of the lower steering shaft added to _h ) is set to zero. Therefore, the handle 12 is rotated to the normal steering wheel angle corresponding to the front wheel steering angle [delta] _f at that time, the state of matching of ends.

The accurate steering angle δ _h corresponding to the yaw rate generated by the automatic steering control at that time is determined in advance experimentally, empirically or theoretically as a parameter of the relationship with the vehicle speed V, road surface friction μ, etc. As a control map and stored in the ROM.

In FIG. 8, in order to facilitate understanding of the effect of the transfer preparation process, the two-degree-of-freedom vehicle motion control not including the vehicle body slip angle β is used instead of the three-degree-of-freedom vehicle motion control including the vehicle body slip angle β described above. did. However, even if it contains the vehicle body slip angle beta, if ask interposed control wheel steering angle [delta] _r after passing through the ARS actuator 800, according to previously vehicle motion model described, the matching of the state quantity any It can be executed without change.

Further, the vehicle state quantity having the highest correlation with the steering wheel angle δ _h is the yaw behavior state quantity including the yaw rate γ, and the vehicle body slip angle β has a sense of incongruity with the steering wheel angle δ _{h as} much as the yaw rate γ. It will not be the cause.

  Next, FIG. 9 will be described.

FIG. 9 explains the effect of the transfer preparation process under a more complicated vehicle movement than FIG. In FIG. 9, as the automatic steering control, the front wheel steering angle δ _f , the rear wheel steering angle δ _r, and the kingpin shaft-around EPS torque τ _eps described in the present embodiment are used as state control amounts for the vehicle body slip angle β, yaw rate γ, and steering. A state in which the three-degree-of-freedom vehicle motion control for independently controlling the reaction torque T _sat is performed is shown.

In particular, in FIG. 9, it is assumed that the ARS actuator 800 is in an abnormal state. That is, the rear wheel steering angle δ _r that should be controllable by the ARS actuator 800 is fixed at the target rear wheel steering angle at a certain time. It is assumed that the termination condition for automatic steering control is satisfied because the ARS actuator 800 is in an abnormal state.

FIG. 9A shows a state in which the vehicle 10 is traveling straight (ie, a state where γ = 0) at a vehicle body slip angle β and a steering wheel angle δ _h that are not zero.

Here, in view of the fact that the first yaw rate (first state quantity) generated by the automatic steering control is zero, the necessary handle angle δ _htg at the time of transfer is also zero, and if the same process as in FIG. 8 is followed. The steering wheel angle δ _h needs to be cut back in the right turning direction in the drawing to realize the steering wheel angle δ _h = 0.

However, if the VGRS actuator 400 is driven and controlled to turn back to the steering wheel angle δ _h = 0 (FIG. 9 (b)), the rear wheel steering angle δr loses controllability. A yaw rate in the direction of the arrow shown in the drawing occurs. As a result, the first yaw rate corresponding to the arrow shown in the figure and the second yaw rate corresponding to the steering wheel angle δh (that is, zero) deviate from each other, and it is not possible to dispel the sense of incongruity when the steering sovereignty is transferred.

  Therefore, an alternative device to be substituted for the ARS actuator 400 is selected by the alternative device selection process (step S204) in the transfer preparation process.

  FIG. 9C illustrates a state where the VGRS actuator 400 is used as an alternative device, and FIG. 9D illustrates a state where the TRC 300 or the ECB 600 is used.

  In FIG. 9C, when the VGRS actuator 400 is used, only the front wheel steering angle δf is in the direction indicated by the broken line in accordance with the control amount for realizing the yaw rate γ = 0 after the handle 12 is returned to the neutral point. Steered. As a result, the first yaw rate related to the automatic steering control and the second yaw rate that should be generated by the steering wheel angle δh (δh = 0) are matched at γ = 0, and there is a sense of discomfort, discomfort and anxiety when the steering sovereignty is transferred. Occurrence is prevented.

9D, when the TRC 300 or the ECB 600 is used, the front wheel left / right braking / driving force difference Ff is indicated by a broken line in accordance with the control amount for realizing the yaw rate γ = 0 after the handle 12 is returned to the neutral point. Is given as follows. As a result, the yaw rate corresponding to the arrow in FIG. 9B is canceled by the yaw moment in the left turn direction in the figure due to the front wheel left / right braking / driving force difference F _f , and the vehicle 10 goes straight in the direction of the solid line in the figure. As a result, the first yaw rate related to the automatic steering control and the second yaw rate that should be generated by the steering wheel angle δ _h (δ _h = 0) are matched at γ = 0, and there is a sense of incongruity, discomfort and anxiety when the steering sovereignty is transferred. Generation of feeling is prevented.

  The transfer preparation process illustrated in FIGS. 9C and 9D is a process for finally matching the yaw rate generated by the automatic steering control with the yaw rate to be generated by the steering wheel angle. This is an example of the control of “matching the state quantity with the second state quantity”.

9 (c) and 9 (d) both show the vehicle 10 traveling straight, but the traveling direction of the vehicle 10 (that is, the vehicle body slip angle β) is different. The straight traveling state that truly corresponds to the steering wheel angle δ _h = 0 is shown in FIG. 9D. This is possible for two types of state control amounts of the front wheel steering angle δ _f and the front wheel left / right braking / driving force difference F _f. This is the result of controllability. On the other hand, in FIG. 9C, the controllable state control amount is only the front wheel rudder angle δ _{f after} all, so if the yaw rate γ is controlled in order to match the first yaw rate and the second yaw rate, The slip angle β cannot be controlled independently. However, the relationship between the steering wheel angle [delta] _h and the vehicle body slip angle β is not important in terms of psychological burden on the driver, be either 9 (c), and FIG. 9 (d), the the driver Occurrence of discomfort, discomfort, or anxiety when the steering sovereignty is transferred is preferably prevented.

Although the vehicle motion model for controlling the vehicle state quantity by the front wheel left / right braking / driving force difference F _f or the rear wheel left / right braking / driving force difference F _r is not described, the front wheel steering angle δ _f , the rear wheel steering The angle δ _r , the front wheel left / right braking / driving force difference F _f , the rear wheel left / right braking / driving force difference F _r, and the EPS torque τ _eps about the kingpin axis, the vehicle body slip angle β, the yaw rate γ, and the steering reaction torque T _sat The relationship with the vehicle state quantity consisting of can be appropriately derived from the basic equation of the vehicle motion model shown in the following equation (5).

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and the vehicle behavior control accompanying such a change is possible. The apparatus is also included in the technical scope of the present invention.

  The present invention can be applied to a vehicle in which the vehicle state quantity can be controlled independently of driver steering.

  FL, FR, RL, RR ... wheels, 10 ... vehicle, 11 ... propeller shaft, 12 ... handle, 13 ... upper steering shaft, 14 ... lower steering shaft, 15 ... rack bar, 16 ... steering angle sensor, 17 ... steering torque Sensor: 100 ... ECU, 200 ... Engine, 300 ... TRC, 310 ... Center differential mechanism, 320 ... Front differential mechanism, 330 ... Rear differential mechanism, 400 ... VGRS actuator, 500 ... EPS actuator, 600 ... ECB, 610 ... Brake actuator , 620FL, 620FR, 620RL, 620RR ... braking device, 800 ... ARS actuator.

Claims (7)

A vehicle behavior control device for controlling the behavior of a vehicle comprising at least one device capable of changing a vehicle state quantity independently of driver steering,
Automatic steering control execution means for executing automatic steering control for converging the vehicle state quantity to a target state quantity via a target apparatus that is at least one of the at least one apparatus;
A handle angle detection means for detecting the handle angle;
When the automatic steering control is switched to driver steering according to the driver's steering, for the one vehicle state quantity correlated with the steering wheel angle in the driver steering, the first state quantity generated by the automatic steering control, and A state quantity matching means for controlling the at least one device so that a second state quantity to be generated coincides with the detected handle angle ;
When at least one of the target devices is in an abnormal state when the automatic steering control is switched to the driver steering, the remaining devices other than the target device in the at least one device are in the abnormal state. As an alternative device to be replaced with at least one, it comprises a selection means for selecting a device that minimizes the state control amount required when the first state quantity and the second state quantity are matched ,
The automatic steering control execution means continues the automatic steering control using the selected alternative device.
A vehicle behavior control device. The vehicle behavior control device according to claim 1, wherein the one vehicle state quantity is a yaw rate. The vehicle behavior control device according to claim 1, wherein the state quantity matching unit matches the second state quantity with the first state quantity. 4. The vehicle behavior control device according to claim 1, wherein the state quantity matching unit matches the first state quantity with the second state quantity. 5. The state quantity matching means changes a degree of matching the first state quantity and the second state quantity according to a deviation between the first state quantity and the second state quantity. The vehicle behavior control apparatus according to any one of claims 1 to 4. The vehicle behavior according to any one of claims 1 to 5, further comprising notification means for notifying a driver that the first state quantity and the second state quantity are matched. Control device. The at least one device is a front wheel rudder angle varying means capable of changing a front wheel rudder angle,
Rear wheel steering angle variable means capable of changing the rear wheel steering angle, auxiliary steering torque supply means capable of supplying auxiliary steering torque to assist the steering torque of the driver, and braking / driving force of the left and right wheels can be changed. The vehicle behavior control device according to any one of claims 1 to 6 , further comprising at least one of various braking / driving force difference varying means.

Images