JP2007186073A - Stabilizer system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve practicality of a stabilizer system for a vehicle capable of actively controlling rigidity of a stabilizer bar by an actuator. <P>SOLUTION: A spring defect is detected based on a motor rotary angle θ when the vehicle is in a non-turning state and a free control is executed, and an active control is executed by adding correction amount θ<SB>0</SB>to suppress inclination of a vehicle body caused by the defect as for a stabilizer device on a defective wheel side (S10). When the defective wheel is a rear wheel, the control is executed by reducing roll suppressing force as compared with that at a normal time (integrating gain K set to be a smaller value than 1) as for the stabilizer device on a front wheel side (S10). When the defective wheel is a front wheel, the control is executed so that a stabilizer device on a rear wheel side may not exert roll suppressing force (S17), and a deviation of roll rigidity distribution is suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle stabilizer system for suppressing a roll of a vehicle body, and particularly to a vehicle stabilizer system having an actuator and configured to be able to change a roll suppression force generated by a stabilizer bar.

Today, so-called active stabilizer systems are beginning to be put into practical use. The active stabilizer system is a system as described in the following patent document, and includes a stabilizer device including a stabilizer bar and an actuator that changes a roll restraining force exhibited by the stabilizer bar, according to the turning state of the vehicle. The actuator can be actively controlled so that the roll restraining force is exerted on the stabilizer bar.
Special table 2002-518245 gazette

  Vehicles have suspension springs (hereinafter sometimes referred to simply as “springs”) for each wheel, and if one of these springs fails and fails to function, the vehicle body tilts. Will occur. Therefore, if the failure of the spring can be dealt with by the active stabilizer system, the practicality of the stabilizer system can be improved. This invention is made | formed based on such a viewpoint, and makes it a subject to provide a highly practical vehicle stabilizer system.

  In order to solve the above-described problems, the vehicle stabilizer system of the present invention is a so-called active stabilizer system that suppresses the leaning of the vehicle body caused by the failure of one of the left and right suspension springs. It is structured.

  The stabilizer system of the present invention is configured to suppress the inclination of the vehicle body caused by the spring failure by the roll restraining force exhibited by the stabilizer bar. According to the system of the present invention, the spring failure Since the inclination of the vehicle body is suppressed even at times, the uncomfortable feeling at the time of spring failure is alleviated. In that respect, the vehicle stabilizer system of the present invention is a highly practical system.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention. In each of the following items, item (1) corresponds to item 1, item (2) to item (4) are combined in item 2, item (6) in item 3, item (7) ) Corresponds to claim 4 respectively.

(1) A stabilizer bar connected to a wheel holding member in which each of both ends holds each of the left and right wheels;
An actuator that changes the roll suppression force exhibited by the stabilizer bar;
A vehicle stabilizer system comprising: a control device that controls a roll restraining force exerted by the stabilizer bar by controlling an operation of the actuator;
The vehicle stabilizer system which has a spring failure time control part which controls the actuator so that the control device may suppress the inclination of the vehicle body due to the failure of one of the left and right suspension springs.

  According to the control executed by the “spring failure control unit” described in this section, the inclination of the vehicle body due to the spring failure can be suppressed by the roll suppressing force exerted by the stabilizer bar. Therefore, according to the stabilizer system of this section provided with the spring failure control unit, it is possible to alleviate or eliminate the uncomfortable feeling caused by the tilting of the vehicle body when the spring fails. In that sense, the stabilizer system in this section is a highly practical system because it can cope with the failure of the spring.

  “Suspension spring failure” in this section mainly means a situation in which the function of the spring cannot be fully or not fully exhibited. Specifically, for example, the spring is a coil spring. In some cases, the situation is such that the air chamber (diaphragm) bursts when it breaks or is an air spring. In such a situation, since the vehicle body is relatively inclined, a sense of discomfort is given to the passengers of the vehicle. In the aspect of this section, it is possible to eliminate or alleviate the uncomfortable feeling. In the aspect of this section, the spring failure control unit may control so as to eliminate the tilt of the vehicle body due to the spring failure at all or almost, and eliminate a part of the tilt. That is, it may be controlled to reduce the inclination.

  The specific configuration of the vehicle stabilizer system described in this section, in particular, the hardware configuration of the “stabilizer device” including the stabilizer bar and the actuator is not particularly limited, and has a known hardware configuration. Active stabilizer systems are widely targeted. For example, as will be described later, the stabilizer bar is divided into two at the center and is constituted by a pair of stabilizer bar members, and an actuator is disposed between the pair of stabilizer bar members. May be configured to cause the pair of stabilizer bar members to rotate relative to each other or generate a force that causes relative rotation, and an actuator is provided between one end of the stabilizer bar and the wheel holding member. The actuator may be arranged so that the actuator generates a force for changing or changing the distance between the one end and the wheel holding member. Furthermore, the actuator may operate based on any force. For example, it may be a fluid actuator that operates by hydraulic pressure or the like, or may be an electromagnetic actuator that includes an electric motor or the like as a drive source, as will be described later. Note that the “control device” described in this section is a device that performs active control, which will be described later, and can be configured mainly by a computer, for example.

  (2) The control device controls the actuator so as to increase a roll restraining force exerted by the stabilizer bar in accordance with an increase in a roll moment received by the vehicle body by turning the vehicle based on a vehicle non-turning state. The vehicle stabilizer system according to item (1).

  This section clarifies that the stabilizer system executes control to change the roll suppression force according to the roll moment received by the vehicle body (hereinafter, this control may be referred to as “active control”). Term. By executing active control, the roll amount of the vehicle body can be effectively suppressed. More specifically, some index amount (hereinafter referred to as “roll moment index amount”) that directly or indirectly indicates the roll moment received by the vehicle body by turning, such as the relationship between the lateral acceleration generated in the vehicle body, the yaw rate, the vehicle speed and the steering amount. The operation of the actuator is controlled based on the The controlled operation may be a force exerted by the actuator (hereinafter sometimes referred to as “actuator force”) or an operation amount of the actuator. Specifically, for example, in a stabilizer device having a structure in which the stabilizer bar exhibits a roll restraining force according to the actuator force, the stabilizer bar of the roll restraining force to be exhibited by both the spring and the stabilizer bar should be shared. The roll restraining force is set as the target roll restraining force, which is determined based on the roll moment index amount, and the actuator force may be controlled so that the target roll restraining force is exhibited. In a stabilizer device that obtains the rigidity of the stabilizer bar (appears as an apparent rigidity), the target actuator operation amount is determined based on the roll moment index amount so as to obtain the rigidity corresponding to the turning state of the vehicle. Then, control is performed so that the operation amount of the actuator becomes the target operation amount. It may be. In other words, the former control is a control in which the roll restraining force is a direct target, and the latter control is indirectly appropriate roll restraint according to the turning state of the vehicle by changing the stiffness of the stabilizer bar. This is a control that exerts its power.

  Furthermore, in the above-mentioned “vehicle non-turning state” (the vehicle is traveling straight or the vehicle is not traveling), the vehicle body is not subjected to the roll moment resulting from the vehicle turning, and the vehicle is When turning, the roll moment received by the vehicle body increases according to the turning state. In the active control according to this aspect, the roll restraining force is increased as the roll moment increases. In this case, the roll restraining force exerted by the stabilizer bar with respect to the roll moment increase (hereinafter, this ratio may be referred to as “stabilizer roll stiffness”) is relatively high, thereby suppressing the roll of the vehicle body. The effect of the roll is increased, and the roll suppression effect is reduced by making the ratio relatively low.

  (3) The control device controls the actuator so that the stabilizer bar does not exert a roll restraining force in a vehicle non-turning state when the suspension spring has not failed. The vehicle stabilizer system according to item (2).

  As described above, in a vehicle non-turning state, the vehicle body does not receive a roll moment resulting from turning. In view of that, in the aspect described in this section, when the spring has not failed, active control is performed in which the roll suppressing force exerted by the stabilizer bar is zero.

  (4) The spring failure control unit controls the actuator so that the stabilizer bar exhibits a failure reference roll suppression force that is a roll suppression force that prevents the vehicle body from tilting in a non-turning state of the vehicle. The vehicle stabilizer system according to any one of (1) to (3).

  The mode described in this section is a mode in which a specific limitation is added with respect to the degree of restraint of the tilt of the vehicle body when the spring fails. According to the aspect described in this section, since the vehicle body does not tilt in the vehicle non-turning state, it is possible to greatly reduce the uncomfortable feeling that the occupant has. Note that the aspect of this section is combined with the above-described aspect, and based on the above-mentioned “reference roll restraining force at the time of failure”, the roll restraining force is determined based on the increase in the roll moment resulting from the turning. It is also possible to implement in such a manner that active control is performed such that the roll restraining force is increased. In this case, for example, when the right wheel spring has failed, when the vehicle turns to the right, the reference roll suppression force at the time of failure assumes a negative value, and this value results from the right turn. Control that increases toward the positive side according to the roll moment is executed.

(5) The stabilizer system is
A configuration capable of changing the roll restraining force of the stabilizer bar in accordance with the operation amount of the actuator, and allowing the actuator to freely move when the stabilizer bar does not exhibit the roll restraining force. And
The vehicle stabilizer system according to any one of (1) to (4), further including a spring failure detection unit that detects a failure of the suspension spring based on an operation amount of the actuator.

  The aspect described in this section is an aspect in which the failure of the spring is detected by the component that the stabilizer system has. If the stabilizer bar does not exhibit roll restraining force as described above and the actuator is allowed to move freely, the amount of operation of the actuator will correspond to the difference in the distance between the left and right wheels and the vehicle body. . Therefore, for example, if the above-mentioned separation distance difference is known when the spring fails in a vehicle non-turning state or the like, the actuator operation amount corresponding thereto is also known, and the actual actuator operation amount is the known When the amount of movement is reached, it can be determined that the spring has failed. The embodiment described in this section can be implemented in such a manner that the spring failure is detected based on the actuator operation amount. According to the aspect of this section, it is possible to easily detect the spring failure without requiring a special sensor such as a stroke sensor.

(6) The stabilizer system includes the stabilizer bar and the actuator on each of the front wheel side and the rear wheel side, and the control device increases the roll moment received by the vehicle body by turning the vehicle based on the vehicle non-turning state. The front wheel side and the rear wheel side actuators are controlled so as to increase the roll restraining force exerted by the front and rear wheel stabilizer bars according to
The spring failure control unit is
When one of the left and right suspension springs on the front wheel side and the rear wheel side fails, one of the actuators on the front wheel side and the rear wheel side is controlled to suppress the tilt of the vehicle body caused by the failure. In addition, the rate of increase in the roll restraining force relative to the increase in the roll moment of the other stabilizer bar on the front wheel side and the rear wheel side where the suspension spring has not failed is compared with the case where the suspension spring has not failed. The vehicle stabilizer system according to any one of (1) to (5), wherein the other actuator is controlled to be small.

  The aspect of this section is an aspect relating to a stabilizer system in which a stabilizer device is disposed on each of the front wheel side and the rear wheel side. Briefly speaking, the side on which the springs on the front wheel side and the rear wheel side have failed (hereinafter, The stabilizer device on the side of the “failed wheel side” may suppress the leaning of the vehicle body caused by the failure, while the springs on the front wheel side and the rear wheel side have not failed (hereinafter referred to as “normal”). This is a mode in which the roll rigidity of the stabilizer device of the “wheel side” is sometimes lowered.

  In general, a vehicle has a roll stiffness distribution between the front wheel side and the rear wheel side (hereinafter, simply referred to as “roll stiffness distribution”) because the turning characteristic is understeered in view of the steering stability of the vehicle. ) Is adjusted to an appropriate value. When one spring on either the left or right side of the front wheel side or the rear wheel side fails, the roll rigidity that the spring should share is greatly reduced due to the failure. Decrease. As a result, the roll stiffness deviates from the appropriately adjusted roll stiffness distribution. The aspect described in this section takes that into consideration, and when the spring is lost on one of the front wheel side and the rear wheel side, the roll rigidity of the stabilizer device on the normal wheel side is reduced, thereby This is a mode in which control is performed to suppress a deviation in roll rigidity distribution. Therefore, according to the aspect described in this section, it is possible to reduce the deterioration of the steering stability of the vehicle.

  (7) When the spring failure control unit controls the actuator on the front wheel side to suppress the leaning of the vehicle body caused by the failure of one of the left and right suspension springs on the front wheel side, The vehicle stabilizer system according to (6), wherein the rear wheel side actuator is controlled so that the stabilizer bar on the rear wheel side does not exert a roll restraining force even when the roll moment increases.

  The aspect of this section is an aspect of an aspect of reducing the roll rigidity of the stabilizer device on the normal wheel side. In order to obtain a turning characteristic with an understeer feeling, it is desirable to suppress the deviation of the roll rigidity distribution toward the rear wheel as much as possible. The mode described in this section is a mode in view of that, and is a mode in which control is performed to eliminate the rigidity of the stabilizer device on the rear wheel side that is the normal wheel side when the spring on the front wheel side fails. is there. Therefore, according to the aspect described in this section, it is possible to reduce the deviation of the roll rigidity distribution to the rear wheel side as much as possible, thereby more reliably reducing the steering stability of the vehicle. It can be reduced.

(8) The stabilizer bar is
Each of them has a torsion bar portion disposed on one axis extending in the vehicle width direction, extends continuously across the torsion bar portion and intersects with the torsion bar portion, and is connected to the wheel holding member at the tip portion. Comprising a pair of stabilizer bar members having arm portions,
The vehicle stabilizer system according to any one of (1) to (7), wherein the actuator relatively rotates a torsion bar portion of the pair of stabilizer bar members around the axis.

  The aspect described in this section is an aspect in which a limitation relating to the specific structure of the stabilizer device is added. According to the aspect of this section, the roll restraining force exerted by the stabilizer bar can be efficiently changed, and for example, the above-described active control can be easily performed.

  (9) The actuator includes a housing, an electric motor each supported by the housing, and a speed reducer that decelerates rotation of the electric motor, and the actuator of the pair of stabilizer bar members The vehicle stabilizer system according to (8), wherein one torsion bar portion is connected to the housing in a relatively non-rotatable manner, and the other torsion bar portion is connected to the output portion of the speed reducer in a relatively non-rotatable manner.

  The mode described in this section is a mode in which the actuator is electrically driven in the active stabilizer system having the above structure, that is, a mode in which a specific structure is limited in the motorized active stabilizer system. In the aspect of this section, the roll restraining force can be easily changed by controlling the electric power supplied to the electric motor. Therefore, according to the aspect of this section, an active stabilizer system with good controllability is provided. Realize.

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

≪Stabilizer system configuration≫
FIG. 1 conceptually shows a vehicle stabilizer system 10 which is an embodiment of the claimable invention. The stabilizer system 10 includes two stabilizer devices 14 disposed on the front wheel side and the rear wheel side of the vehicle. Each of the stabilizer devices 14 includes a stabilizer bar 20 connected to each of the wheel holding members that hold the left and right wheels 16 at both ends via a link rod 18 as a connecting member (see FIG. 2). The stabilizer bar 20 is divided at the center, and includes a pair of stabilizer bar members, that is, a right stabilizer bar member 22 and a left stabilizer bar member 24. The pair of stabilizer bar members 22 and 24 are connected to each other via an actuator 30 so that they can rotate relative to each other. Generally speaking, the stabilizer device 14 causes the actuator 30 to rotate the left and right stabilizer bar members 22 and 24 relative to each other. Thus (refer to the arrows and dotted arrows in the figure), the apparent rigidity of the entire stabilizer bar 20 is changed to suppress the roll of the vehicle body.

  FIG. 2 schematically shows a portion from the center in the vehicle width direction of one stabilizer device 14 to the wheel 16 on one side. The vehicle equipped with the stabilizer system 10 includes four independent suspension devices 38 provided for each of the four wheels 16. The suspension device 38 is of a generally well-known double wishbone type, and has an upper arm 42 as a wheel holding member whose one end is rotatably connected to the vehicle body and the other end is connected to the wheel 16. And a lower arm 44. The upper arm 42 and the lower arm 44 are rotated around the one end portion (vehicle body side) with the approach and separation of the wheel 16 and the vehicle body (meaning relative vertical movement), and the other end portion (wheel side). ) Is moved up and down with respect to the vehicle body. The suspension device 38 includes a shock absorber 46 and a suspension spring 48 (in the present device, an “air spring”). The shock absorbers 46 and the springs 48 are respectively connected at one end to the vehicle body side mount and at the other end to the lower arm 44. Due to such a structure, the suspension device 38 functions to elastically support the wheel 16 and the vehicle body, and to generate a damping force against vibration accompanying the approaching and separation.

  The stabilizer device 14 includes a right stabilizer bar member 22 and a left stabilizer bar member 24, which are the pair of stabilizer bars described above (FIG. 2 shows one of the right stabilizer bar member 22 and the left stabilizer bar member 24). Have been). Each of the stabilizer bar members 22 and 24 is divided into a torsion bar portion 60 that extends substantially in the vehicle width direction and an arm portion 62 that is integrated with the torsion bar portion 60 and that intersects with the torsion bar portion 60 and extends generally forward or rearward of the vehicle. be able to. The torsion bar portion 60 of each stabilizer bar member 22, 24 is rotatably supported by a support member 66 fixedly provided on a stabilizer device disposition portion 64 that is a part of the vehicle body at a location near the arm portion 62. Are arranged coaxially with each other. Between the end portions of the torsion bar portions 60 (end portion on the center side in the vehicle width direction), the above-described actuator 30 is disposed, which will be described in detail later. Are connected to the actuator 30. On the other hand, the end portion of the arm portion 62 (the end portion opposite to the torsion bar portion 60 side) is connected to the stabilizer bar connecting portion 68 provided on the lower arm 44 via the link rod 18.

  As schematically shown in FIG. 3, the actuator 30 includes an electric motor 70 and a speed reducer 72 that decelerates the rotation of the electric motor 70. The electric motor 70 and the speed reducer 72 are provided in a housing 74 that is an outer shell member of the actuator 30. The housing 74 is held by the housing holding member 76 in a stabilizer device arrangement portion 64 provided on the vehicle body so as to be rotatable and immovable in the axial direction (substantially in the vehicle width direction). As can be seen from FIG. 2, the two output shafts 80 and 82 are disposed so as to extend from both ends of the housing 74. The ends of the output shafts 80 and 82 extending from the housing 74 are connected to the ends of the stabilizer bar members 22 and 24 so as not to rotate relative to each other by serration fitting. As can be seen from FIG. 3, one output shaft 80 is fixedly connected to the end of the housing 74, and the other output shaft 82 is disposed so as to extend into the housing 74. In addition, it is supported so as to be rotatable with respect to the housing 74 and immovable in the axial direction. One end portion of the output shaft 82 existing in the housing 74 is connected to a speed reducer 72 as will be described in detail later. The output shaft 82 also serves as the output shaft of the speed reducer 72. .

  The electric motor 70 includes a plurality of stator coils 84 fixedly arranged on one circumference along the inner surface of the peripheral wall of the housing 74, a hollow motor shaft 86 rotatably held in the housing 74, and a motor. A permanent magnet 88 is disposed on the outer periphery of the shaft 86 so as to face the stator coil 84 and be fixed on one circle. The electric motor 70 is a motor in which the stator coil 84 functions as a stator and the permanent magnet 88 functions as a rotor, and is a three-phase DC brushless motor.

  The reduction gear 72 includes a wave generator 90, a flexible gear (flex spline) 92, and a ring gear (circular spline) 94, and a harmonic gear mechanism (harmonic drive mechanism (registered trademark), strain wave gearing mechanism, etc. Also called). The wave generator 90 is configured to include an elliptical cam and a ball bearing fitted on the outer periphery thereof, and is fixed to one end of the motor shaft 86. The flexible gear 92 has a cup shape in which the peripheral wall portion can be elastically deformed, and a plurality of teeth are formed on the outer periphery on the opening side of the peripheral wall portion. The flexible gear 92 is connected to and supported by the output shaft 82 described above. Specifically, the output shaft 82 passes through the motor shaft 86, and the flexible gear 92 and the output shaft 82 are connected to each other by fixing the bottom of the flexible gear 92 to the end extending from the motor shaft 86. is there. The ring gear 94 is generally formed in a ring shape and has a plurality of teeth (a slightly larger number than the number of teeth of the flexible gear, for example, two more) than the number of teeth of the flexible gear, and is fixed to the housing 74. The flexible gear 92 has a peripheral wall that is externally fitted to the wave generator 90 and is elastically deformed into an elliptical shape. The flexible gear 92 meshes with the ring gear 94 at two positions located in the major axis direction of the ellipse and does not mesh at other positions. It is said that. When the wave generator 90 makes one rotation (360 degrees), that is, when the motor shaft 86 of the electric motor 70 makes one rotation, the flexible gear 92 and the ring gear 94 are relatively rotated by the difference in the number of teeth.

  From the above configuration, when a vehicle turns or the like, a force that relatively changes the distance between one of the left and right wheels 16 and the vehicle body and the distance between the other of the left and right wheels 16 and the vehicle body, that is, a roll moment acts on the vehicle body. The force that relatively rotates the right stabilizer bar member 22 and the left stabilizer bar member 24, that is, the external input to the actuator 30 acts. In that case, the actuator 30 is externally driven by a motor force that is a force generated by the electric motor 70 (the electric motor 70 is a rotary motor and may be considered as a rotary torque, and may be referred to as a rotary torque). When the force balanced with the input is exerted as the actuator force, one stabilizer bar 20 constituted by the two stabilizer bar members 22 and 24 is twisted. The elastic force generated by this twist becomes a force that opposes the roll moment, that is, a roll restraining force. Then, the right stabilizer bar member 22 and the left stabilizer bar member 24 are changed by changing the relative rotational position of the output shafts 80 and 82 of the actuator 30, that is, the rotational position of the actuator 30 (that is, the operating position) by the motor force. If the vehicle body receives the same roll moment, in other words, even if the same roll restraining force is generated, the roll amount of the vehicle body can be changed. It becomes. The stabilizer device 14 is thus a device capable of changing the apparent rigidity of the stabilizer bar 20, that is, the stabilizer rigidity.

  The actuator 30 is provided with a motor rotation angle sensor 100 in the housing 74 for detecting the rotation angle of the motor shaft 86, that is, the rotation angle of the electric motor 70. The motor rotation angle sensor 100 mainly includes an encoder in the actuator 30, and determines the relative rotation angle (relative rotation position) of the left and right stabilizer bar members 22, 24, in other words, the operation position, that is, the rotation position of the actuator 30. As an index, it is used for control of the actuator 30, that is, control of the stabilizer device 14.

  As shown in FIG. 1, electric power is supplied to the electric motor 70 included in the actuator 30 from a battery 102 as a power source. In the present stabilizer system 10, an inverter 104 is provided between the battery 102 and each of the two stabilizer devices 14. The inverters 104 function as a drive circuit, and electric power is supplied to the electric motor 70 included in each of the two stabilizer devices 14 via each of the two inverters 104. Since the electric motor 70 is driven at a constant voltage, the amount of supplied power is changed by changing the amount of supplied current, and the electric motor 70 exhibits a force corresponding to the amount of supplied current. Incidentally, the amount of supply current is performed by the inverter 104 changing the ratio (duty ratio) between the pulse-on time and the pulse-off time by PWM (Pulse Width Modulation).

  As shown in FIG. 1, the stabilizer system 10 includes a stabilizer device 14, specifically, a stabilizer electronic control unit (ECU) 110 (hereinafter simply referred to as “ECU 110”) that is a control device that controls the operation of the actuator 30. ). The ECU 110 is mainly composed of a computer having a CPU, a ROM, a RAM, and the like. The ECU 110, together with the motor rotation angle sensor 100, operates a steering wheel that is an operation amount of a steering operation member as a steering amount. An operation angle sensor 120 for detecting an angle, a vehicle speed sensor 122 for detecting a vehicle traveling speed (hereinafter sometimes abbreviated as “vehicle speed”), and an actual lateral acceleration that is a lateral acceleration actually generated in the vehicle body is detected. A lateral acceleration sensor 124 is connected. (In FIG. 1, they are represented as “θ”, “δ”, “v”, and “Gy”, respectively). The ECU 110 is also connected to the inverter 104, and the ECU 110 controls the rotational position of the actuator 30 by controlling the inverter 104. The ROM included in the computer of the ECU 110 stores a stabilizer control program, which will be described later, various data related to the control of the stabilizer device 14, and the like.

≪Control executed in stabilizer system≫
In the present stabilizer system 10, in principle, the target operation amount of the actuator 30 is determined based on the turning state of the vehicle, and by controlling the actuator 30 so that the actual operation amount of the actuator 30 becomes the target operation amount, Change the stabilizer stiffness. That is, it is possible to actively control the roll restraining effect of the vehicle body, that is, the roll amount of the vehicle body according to the roll moment received by the vehicle body (hereinafter, this control may be referred to as “active control”). In this active control, the actuator 30 is controlled so that the stabilizer bar 20 does not exert the roll restraining force particularly when the vehicle is stopped or substantially straight, that is, in a non-turning state. Free control is to be executed. In the present stabilizer system 10, during the execution of the free control, based on the detection value of the motor rotation angle sensor 100, a spring failure detection process for detecting the inclination of the vehicle body due to the failure of the spring 48 is executed. Has been. When the spring failure is recognized, control corresponding to the spring failure (hereinafter, this control may be referred to as “spring failure control”) is executed.

(A) Active control In the active control, the target rotational position, which is the target operation amount of the actuator 30, in order to make the torsional rigidity of the stabilizer bar 20 appropriate based on the roll moment index amount indicating the roll moment received by the vehicle body. Is determined, and control is performed so that the rotational position of the actuator 30 becomes the target rotational position. That is, based on the roll moment index amount, in order to generate a roll restraining force so that the roll amount of the vehicle body becomes an appropriate amount, the actuator is configured to relatively rotate the pair of stabilizer bar members 22 and 24 by an appropriate angle. 30 is controlled. Here, the rotation position of the actuator 30 means the rotation amount from the neutral position when the rotation position of the actuator 30 in the reference state in which no roll moment acts on the vehicle body is a neutral position. To do. That is, it means a displacement amount to the neutral position, which is a displacement amount with respect to the neutral position of the operating position of the actuator 30. Further, since the rotational position of the actuator 30 and the motor rotational angle that is the rotational angle of the electric motor 70 are in a corresponding relationship, the motor rotational angle is used in place of the rotational position of the actuator 30 in actual control.

More specifically, in the present embodiment, the target motor rotation as a target rotation position (a kind of target operation amount) of the actuator 30 based on the lateral acceleration as the roll moment index amount in the present embodiment. The angle θ * is determined. More specifically, based on the estimated lateral acceleration Gyc estimated based on the steering wheel operating angle and the vehicle traveling speed, and the actually measured actual lateral acceleration Gyr, the control lateral acceleration Gy, which is the lateral acceleration used for control, is used. * Is determined according to the following equation:
_{Gy * = K 1 · Gyc +} K 2 · Gyr
Here, K ₁ and K ₂ are gains, and the target motor rotation angle θ * is determined based on the control lateral acceleration Gy * determined as described above. Then, the target supply current i * to the electric motor 70 is determined according to the feedback control method based on the deviation between the target motor rotation angle θ * and the actual motor rotation angle θ, which is the actual motor rotation angle, that is, the actuator 30. Therefore, appropriate electric power is supplied to the electric motor 70 of the actuator 30 in order to bring the rotation position of the actuator close to the target rotation position or to maintain the rotation position at the target rotation position.

  During execution of active control, free control is executed when the vehicle has been in a non-turning state for a certain period of time or longer. In the free control, an energization mode in which energization to each phase of the electric motor 70 is interrupted is employed. As a result, it is almost as if the connection between each phase of the electric motor 70 and the inverter 104 is disconnected. In the free control, an electromotive force is not generated in the electric motor 70, and the braking effect by the electric motor 70 is hardly obtained. Therefore, if the free control is executed, the stabilizer bar 20 becomes almost incapable of exhibiting rigidity, and the vehicle is almost in a state not including the stabilizer.

  In the normal state, that is, when the suspension spring 48 is not lost on either the front wheel side or the rear wheel side, the above-described active control is executed on both the front wheel side and the rear wheel side.

(B) Spring failure detection processing In the spring failure detection processing, when any one of the front, rear, left and right suspension springs 48 is lost due to an air chamber burst or the like, the inclination of the vehicle body accompanying the failure is detected. This is a process of detecting which wheel has failed. FIG. 4 shows, as an example, a front view of the stabilizer device 14 and the suspension device 38 on the failed wheel side (in this case, the front wheel side) when the spring 48 provided for the left front wheel 16fl has failed. Show. As can be seen from this figure, if the spring 48 fails, the vehicle body and the wheel 16fl approach each other until the bound stopper functions, and the vehicle body is tilted accordingly. From the normal posture of the vehicle body indicated by the broken line in the figure, the vehicle body is inclined as indicated by the solid line. Here, when the vehicle is in a non-turning state and the above-described free control is being executed, the operating position of the actuator 30 is normally a neutral position. With the separation distance difference between the wheel and the vehicle body, the actuator operating position deviates from the neutral position. The difference in the separation distance between the vehicle body and the wheel when the spring 48 is lost is known depending on the vehicle type, and the actuator operation position corresponding thereto is also known. Accordingly, in the present stabilizer system 10, when the free control is continuously executed for the set time, the spring failure detection process is executed, and the operating position of the actuator 30 (specifically, the actual motor rotation angle corresponding thereto). When the absolute value of θ exceeds the set threshold value, it is determined that the spring 48 is in a failed state. Further, it is possible to determine which spring 48 of the left and right wheels 16 has failed depending on the rotation direction from the neutral position of the actual motor rotation angle θ. This spring failure detection process is executed for each of the front wheel side and the rear wheel side.

(C) Control at the time of spring failure If a spring failure is detected, the stabilizer device 14 on the failed wheel side is controlled to exert its roll restraining force that suppresses the tilt and suppresses the roll moment generated during turning. (Hereinafter, this control may be referred to as “failed wheel side control”). On the other hand, the normal wheel side stabilizer device 14 is controlled so as to reduce the roll rigidity (hereinafter, this control may be referred to as “normal wheel side control”).

(i) Missed wheel side control As described above, the magnitude of the inclination of the vehicle body when the spring 48 is missing is known, and correspondingly, in this embodiment, the vehicle is in a non-turning state. In this case, a roll restraining force having a magnitude that eliminates the inclination of the vehicle body is preset as a reference roll restraining force at the time of failure. In the failed wheel side control, the stabilizer bar 20 exhibits a roll restraining force obtained by adding the reference roll restraining force at the time of failure to the roll restraining force determined according to the turning state of the vehicle in the normal active control. Control of the actuator 30 is executed. Specifically, the correction amount θ ₀ of the motor rotation angle corresponding to the reference roll suppression force at the time of failure is preset, and the correction amount θ is added to the target motor rotation angle θ * determined in the above-described active control. Control is executed with a value obtained by adding ₀ as a new target motor rotation angle θ *. The stabilizer device 14 on the failed wheel side is controlled so as to suppress the roll moment resulting from the turn while eliminating the inclination of the vehicle body due to the failure.

(ii) Normal wheel side control The roll stiffness distribution between the front wheel side and the rear wheel side is in a state of being appropriately adjusted in advance. In general, the roll rigidity of the front wheel side of the so-called FF (front engine front drive) or FR (front engine rear drive) vehicle in which the drive source is arranged forward is because the turning characteristic is understeered. Specifically, the roll rigidity distribution between the front wheel side and the rear wheel side is adjusted so that the front wheel side is 60 to 65% and the rear wheel side is 40 to 35%. However, if the spring 48 of the suspension device 38 corresponding to any of the four wheels fails, the roll rigidity of the suspension device 38 on the failed side decreases, and the suspension device 38 and stabilizer on the failed wheel side decrease. The roll rigidity that the apparatus 14 exerts jointly decreases. In such a state, if the same control as when all the springs 48 are normal is executed for the stabilizer device 14 on the normal wheel side, the roll stiffness distribution on the normal wheel side will increase, and the front wheel side and the rear wheel side will be increased. The roll stiffness distribution with the wheel side will deviate from the appropriately adjusted state. Therefore, for the normal wheel side, the control is executed to suppress the deviation of the roll stiffness distribution by reducing the roll stiffness of the stabilizer device 14 in accordance with the decrease of the roll stiffness on the failed wheel side, thereby stabilizing the steering. It is supposed to ensure sex.

  Incidentally, in the normal wheel side control, the control differs depending on whether the normal wheel side is the front wheel side or the rear wheel side. When the normal wheel side is the front wheel side, that is, when the spring 48 has failed on the rear wheel side, the front wheel side is set to a value smaller than 1 for the target motor rotation angle θ * determined in the normal active control. By accumulating a certain gain K ′, a new target motor rotation angle θ * is determined, and the electric motor 70 is controlled so as to realize the target motor rotation angle θ *. More specifically, as shown in the graph of FIG. 5, the target value of the roll suppression force (that is, the target motor rotation angle θ *) is increased in accordance with the increase in the control lateral acceleration Gy * that is the roll moment index amount. In normal active control when there is no spring failure, the gain K, which is the rate of increasing the roll restraining force, is set to 1. In contrast, the stabilizer device 14 on the front wheel side, which is the normal wheel side when the spring 48 on the rear wheel side fails, increases the roll suppression force by setting the gain K to a gain K ′ smaller than 1. Control is performed such that the ratio is reduced, that is, the roll rigidity of the stabilizer bar 20 is reduced.

  When the normal wheel side is the rear wheel side, that is, when the spring 48 is missing on the front wheel side, control is performed on the rear wheel side so that the roll stiffness of the stabilizer bar 20 is zero. More specifically, if the roll stiffness distribution on the front wheel side has been increased in advance as described above, assuming that either the left or right spring 48 on the rear wheel side has failed, the roll stiffness distribution on the rear wheel side is originally Therefore, the rate at which the roll stiffness is reduced due to the failure is small, and accordingly the rate at which the roll stiffness on the front wheel side, which is the normal wheel side, is reduced is small. On the other hand, when either of the left and right springs 48 on the front wheel side has failed, the roll rigidity distribution on the front wheel side is large, so in order to suppress the deviation of the roll rigidity distribution due to the front wheel side failure, It is desirable that the roll rigidity of the stabilizer device 14 on the rear wheel side be as small as possible. In view of this, the stabilizer bar 20 is controlled so as not to exert the roll restraining force. Specifically, the above-mentioned free control is executed for the stabilizer device 14 on the rear wheel side.

≪Stabilizer control program≫
The stabilizer control program shown in the flowchart of FIG. 6 is repeatedly executed by the stabilizer ECU 110 at short time intervals (for example, several m to several tens of msec) while the ignition switch is turned on. Is done. Note that the flowchart shown in FIG. 6 is a program executed for one of the front wheel side and the rear wheel side. In practice, the program is executed for each of the front wheel side and rear wheel side stabilizer devices 14. Is done. In the following, the flow of stabilizer control will be described in detail with reference to the flowchart shown in the figure. However, in order to avoid redundant description, the front wheel side and the rear wheel side will be described in common. That is, when the spring is lost, the normal wheel side and the wheel side where the spring 48 is lost will be described in parallel.

In the stabilizer control program, first, in step 1 (hereinafter simply referred to as “S1”, the same applies to other steps), the correction amount θ ₀ and the gain K for correcting the target motor rotation angle θ * are specified. Is done. The initial value of the correction amount θ ₀ is 0, and the initial value of the gain K is 1. These values are determined when another value is determined later. Next, in S <b> 2, the vehicle speed v and the steering wheel operation angle δ are acquired based on the detection values of the vehicle speed sensor 122 and the operation angle sensor 120, respectively.

Next, in S3 and S4, the turning state of the vehicle is determined. In S3, the vehicle speed v is determined whether greater than the set threshold value v _1, in S4, whether or not the operation angle of the steering wheel [delta] is larger than the set threshold value [delta] ₁ is determined. If both the vehicle speed v and the operation angle δ are larger than the set threshold values v ₁ and δ ₁ , it is determined that the vehicle is turning and the process proceeds to S5.

  In S5, the time counter t is set to zero. This time counter t is a counter representing the time during which the vehicle is not turning, and is returned to the initial value 0 when it is determined that the vehicle is turning. Next, in S6, the estimated lateral acceleration Gyc is estimated based on the vehicle speed v and the operation angle δ acquired in S2. The ECU 110 stores map data related to the estimated lateral acceleration Gyc using the vehicle speed v and the operation angle δ as parameters, and the estimated lateral acceleration Gyc is estimated by referring to the map data. Subsequently, in S <b> 7, the actual lateral acceleration Gyr that is the lateral acceleration actually generated in the vehicle body is acquired based on the detection value of the lateral acceleration sensor 124. In subsequent S8, the control lateral acceleration Gy * is determined from the estimated lateral acceleration Gyc and the actual lateral acceleration Gyr as described above, and in S9, the target motor rotation angle θ * is determined based on the control lateral acceleration Gy *. The The ECU 110 stores map data of the target motor rotation angle θ * using the control lateral acceleration Gy * as a parameter. In S9, the target motor rotation angle θ * is determined with reference to the map data. .

Next, in S10, the target motor rotational angle theta * is corrected based on the correction amount theta ₀ and the gain K specified in S1. When the correction amount θ ₀ is 0 and the gain K is 1 which is an initial value, the correction is not substantially performed. That is, when the spring 48 has not failed on both the front wheel side and the rear wheel side, the target motor rotation angle θ * for executing normal active control is determined. On the other hand, when the spring 48 has failed, as will be described later, the correction amount θ ₀ exerts the reference roll restraining force at the time of the failure for the stabilizer device 14 on the failed wheel side in the failure detection program. With respect to the stabilizer device 14 on the normal wheel side, the gain K is set so as to reduce the roll rigidity, and the correction based on the gain K is executed. Specifically, when the rear wheel side spring fails, the gain K of the front wheel side stabilizer device 14 is determined to be K ′ (≠ 0), which is a value smaller than 1 described above, and the normal wheel The roll rigidity of the stabilizer bar 20 on the front wheel side, which is the side, is reduced to a magnitude corresponding to the value. Further, when the front wheel side spring 48 is lost, the gain K is set to 0 for convenience in order to perform control so that the stabilizer bar 20 on the rear wheel side does not exert the roll suppressing force. When the gain K is set to 0, as a result of the subsequent determination of S11, the process proceeds to S17, and free control is executed regardless of the value of the target motor rotation angle θ * (in practice, to enter the free control state). Is output to the inverter 104). Further, for the stabilizer device 14 on the failed wheel side, since the reference roll suppression force at the time of failure according to the correction amount θ ₀ is added to the target motor rotation angle θ *, the inclination of the vehicle body due to the failure of the spring 48 is achieved. Will be suppressed.

  If the gain K is not 0 in the determination in S11, the process proceeds to S12 and S13, and active control based on the target motor rotation angle θ * determined in S9 is executed. Specifically, in S12, as described above, the target supply current i * is determined based on the target motor rotation angle θ *. In S13, the control signal for the target supply current i * is sent to the inverter 104. Is output. This completes one execution of the program.

In S3 and S4 described above, when either the vehicle speed v or the operation angle δ is equal to or less than the set threshold values v ₁ and δ ₁ , that is, even if the vehicle is stopped or the vehicle is running. If it can be considered that the vehicle is in a straight traveling state, the process proceeds to S14 to determine whether or not to execute free control. First, in S14, it is determined whether or not the correction amount θ ₀ is the initial value 0. When the correction amount θ ₀ is not ₀ , the value of the correction amount θ ₀ is set so that the stabilizer bar 20 exerts a roll suppression force obtained by adding the reference roll suppression force at the time of failure corresponding to the spring failure. because if it is, the vehicle is also a non-turning state, the process proceeds to step S5 following active control based on the correction amount theta ₀ target motor rotational angle by adding the theta * is executed.

On the other hand, if all the springs 48 of the four wheels 16 are normal and the correction amount θ ₀ is set to 0, the process proceeds to S15 and S16, and whether the vehicle is in a non-turning state for a set time. It is determined whether or not. Specifically, 1 is added to the time counter t indicating the time during which the vehicle is not turning in S15, and it is determined whether or not the time t is greater than the set value T in S16. If the time counter t is less than or equal to the set value T, the determination in S16 is NO and the control in S6 and subsequent steps is executed. If the time t is greater than the set time T, the process proceeds to S17 and free control is executed. Specifically, a command that the electric motor 70 operates based on the free control described above is issued to the inverter 104. This completes one execution of the program.

<< Fault detection program >>
The spring failure detection process of the suspension device 38 is short while the failure detection program shown in the flowchart in FIG. 7 is in the ON state for each of the front wheel side and rear wheel side stabilizer devices 14. This is performed by being repeatedly executed by the ECU 110 at time intervals (for example, several m to several tens msec). This program is executed in parallel with the previous stabilizer control program, but is not executed after it is recognized that the spring 48 provided for any of the wheels 16 has once lost. Yes. Hereinafter, the flow of the spring failure detection process will be described in detail with reference to the flowchart shown in the drawing.

In the failure detection program, first, in S21, it is determined whether or not free control is currently being executed. When the free control is not executed, the failure detection process is not performed. That is, in S22, the time counter t _F indicating the time during which the free control is continuously executed is set to 0, and one execution of this program is completed.

If free control is being executed, the process proceeds to S23, 1 is added to the time counter t _F. Next, in S24, it is determined whether or not the value of the time counter t _F exceeds the set value T _F. If the value of the time counter t _F is equal to or less than the set value T _F , the determination in S24 is NO, and one execution of this program ends. When the free control is continuously executed beyond the time corresponding to the set value T _F , the process proceeds to S25 and subsequent steps, and the failure detection process is executed.

In S25, the actual motor rotation angle θ is acquired based on the detection value of the motor rotation angle sensor 100. In subsequent S26, it is determined whether or not the absolute value of the actual motor rotation angle θ is equal to or larger than a set threshold value θ ′. When the absolute value of the actual motor rotation angle θ is smaller than the set threshold value θ ′, it is determined that none of the left and right springs 48 on the side where the stabilizer device including the electric motor 70 is provided has failed. This completes one execution of the program. If the absolute value of the actual motor rotation angle θ is greater than or equal to the set threshold value θ ′ in S26, the process proceeds to S27 and it is determined that either of the left and right springs 48 has failed. Based on the sign of the actual motor rotation angle θ, authorization is performed including whether the left and right springs 48 have failed (based on the direction of rotation from the neutral position). Next, in S28, the value of the target motor rotational angle theta * correction amount theta _0, and the value of the gain K for the stabilizer device 14 of the normal wheel side are determined with respect to the stabilizer device 14 of the failure wheel side. The correction amount θ ₀ has a predetermined size, and has a different sign depending on which of the left and right springs 48 has failed. The gain K of the stabilizer device 14 on the normal wheel side is set to 0 when one of the left and right springs 48 on the front wheel side fails, and when one of the springs 48 on the rear wheel side fails, The gain K ′ is set as described above. This completes one execution of the program.

<Functional configuration of control device>
The ECU 110, which is a control device of the present stabilizer system 10 that functions by executing the stabilizer control program as described above, as shown in FIG. 8, uses the active control unit 130 as a function unit that executes the processes of S1 to S17. In particular, the active controller 130 includes a spring failure control unit 132 as a functional unit that executes the processes of S1 and S10, and a spring failure detection unit 134 as a functional unit that executes the processes of S21 to S28. Yes.

It is a schematic diagram which shows the whole structure of the stabilizer system of an Example. It is the schematic which shows the stabilizer apparatus with which the stabilizer system of FIG. 1 is provided. It is a schematic sectional drawing which shows the actuator which comprises the stabilizer apparatus of FIG. It is a figure which shows notionally the spring failure state of the vehicle provided with the stabilizer system of FIG. It is a graph which shows the roll suppression force which the stabilizer apparatus of FIG. 1 exhibits. It is a flowchart which shows the stabilizer control program performed in the stabilizer system of FIG. It is a flowchart which shows the failure detection program performed in the stabilizer system of FIG. It is a block diagram which shows the function of the stabilizer electronic control unit as a control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Stabilizer system for vehicles 14: Stabilizer apparatus 18: Link rod 20: Stabilizer bar 22: Right stabilizer bar member 24: Left stabilizer bar member 30: Actuator 60: Torsion bar part 62: Arm part 70: Electric motor 72: Reduction gear 74: Housing 104: Inverter (drive circuit) 110: Stabilizer electronic control unit (ECU) (control device) 120: Operating angle sensor 122: Vehicle speed sensor 124: Lateral acceleration sensor 130: Active control unit 132: Control unit when spring fails 134: Spring failure detection unit

Claims (4)

A stabilizer bar connected to a wheel holding member in which each of both ends holds each of the left and right wheels;
An actuator that changes the roll suppression force exhibited by the stabilizer bar;
A vehicle stabilizer system comprising: a control device that controls a roll restraining force exerted by the stabilizer bar by controlling an operation of the actuator;
The vehicle stabilizer system which has a spring failure time control part which controls the actuator so that the control device may suppress the inclination of the vehicle body due to the failure of one of the left and right suspension springs. The control device increases the roll restraining force exerted by the stabilizer bar in response to an increase in the roll moment received by the vehicle body by turning the vehicle with reference to the vehicle non-turning state, and the suspension spring has failed. If not, the actuator bar is controlled so that the stabilizer bar does not exert a roll restraining force in a vehicle non-turning state,
The spring failure control unit controls the actuator so that the stabilizer bar exhibits a failure reference roll suppression force that is a roll suppression force that prevents the vehicle body from tilting when the vehicle is not turning. The vehicle stabilizer system according to claim 1. The stabilizer system includes the stabilizer bar and the actuator on each of the front wheel side and the rear wheel side, and the control device responds to an increase in roll moment received by the vehicle body by turning the vehicle based on the vehicle non-turning state. The front wheel side and the rear wheel side actuators are controlled so as to increase the roll restraining force exerted by the front and rear wheel stabilizer bars,
The spring failure control unit is
When one of the left and right suspension springs on the front wheel side and the rear wheel side fails, one of the actuators on the front wheel side and the rear wheel side is controlled to suppress the tilt of the vehicle body caused by the failure. In addition, the rate of increase in the roll restraining force relative to the increase in the roll moment of the other stabilizer bar on the front wheel side and the rear wheel side where the suspension spring has not failed is compared with the case where the suspension spring has not failed. The vehicle stabilizer system according to claim 1 or 2, wherein the other actuator is controlled to be small. The spring failure control unit controls the actuator on the front wheel side to suppress the leaning of the vehicle body caused by the failure when one of the left and right suspension springs on the front wheel side fails, The vehicle stabilizer system according to claim 3, wherein the actuator on the rear wheel side is controlled so that the stabilizer bar does not exhibit a roll restraining force even when a roll moment increases.

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