JP2006219048A - Stabilizer system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the practicality of an active stabilizer equipped with an actuator changing the rigidity of a stabilizer bar. <P>SOLUTION: When a vehicle is in a straight traveling state (S12), the operation mode of an electric motor of the actuator is made to be a state (S13) where there is little braking as a free mode to make an input line of each phase of the electric motor in the opening state. When an operation angular speed dδ is smaller than a threshold speed dδ1 (S15), it is made to be a control mode (S16) performing the active roll suppressing control. When the operation angular speed dδ is not less than the threshold speed dδ1, that is, in high speed steering, the delay of the control is avoided and the roll of the vehicle body is effectively suppressed (S17) by short-circuiting the electric motor 70, that is, making the braking mode to obtain the braking state by the short-circuit braking. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stabilizer system that includes a stabilizer bar to suppress a roll of a vehicle body, and more particularly, to a stabilizer system that can change the rigidity of a stabilizer bar.

The stabilizer system is a system that suppresses the roll of the vehicle body when the vehicle turns, for example, using the rigidity of the stabilizer bar. In recent years, a so-called active stabilizer system, specifically, a system that effectively suppresses rolls by changing the stiffness of a stabilizer bar according to the turning state of a vehicle by an actuator has been studied. Examples of active stabilizers that have been studied in the past include systems described in the following patent documents. Incidentally, the system described in Patent Document 1 is a system including an actuator that is hydraulically driven, and the system described in Patent Document 2 is a system including an actuator that uses an electric motor as a drive source. .
Japanese Patent Laid-Open No. 7-40731 Special table 2002-518245 gazette

  The active stabilizer is an operation of the actuator to generate a roll restraining moment that opposes the roll moment acting on the vehicle body based on the lateral acceleration received by the vehicle body that indicates the turning state of the vehicle by a control device equipped with a computer or the like. Is controlled. However, when the turning state of the vehicle changes abruptly and the lateral acceleration or the like changes abruptly, there is a problem that the control does not follow and a sufficient roll restraining moment cannot be generated. This problem is just one problem with active stabilizers, but conventional active stabilizers have a variety of problems, leaving plenty of room to improve their practicality by addressing those problems. Yes. This invention is made | formed in view of such a situation, and makes it a subject to aim at the improvement of the practicality of a stabilizer system.

  In order to solve the above-described problem, the stabilizer system of the present invention is configured to control the actuator when the steering speed exceeds the set threshold speed in the control of the actuator capable of changing the rigidity of the stabilizer bar. The braking state is limited in its operation.

  In the stabilizer system of the present invention, since the actuator changes the rigidity of the stabilizer bar according to its operation, the change in the rigidity of the stabilizer bar can be restricted by restricting the operation of the actuator. As a result, a state in which the stabilizer bar has a predetermined rigidity is realized. In the stabilizer system of the present invention, the actuator is brought into a braking state at the time of high-speed steering, which is a case where the turning state of the vehicle changes suddenly. Can be avoided. Because of such advantages, the stabilizer system of the present invention becomes a practical active stabilizer 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 constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  In each of the following items, (1) corresponds to claim 1, and the combination of technical features of items (3) and (4) with claim 1 is claimed in claim 2 and claim 2 A combination of the technical features of (8) corresponds to claim 3 respectively.

(1) A vehicle including a stabilizer bar having both ends connected to the left and right wheels, an actuator that changes the rigidity of the stabilizer bar by its own operation, and a control device that controls the operation of the actuator. Stabilizer system for
The control device includes a high-speed steering control unit that sets the actuator to a braking state in which the operation of the actuator is restricted when the steering speed exceeds a set threshold speed. Stabilizer system.

  The vehicle stabilizer system described in this section is a roll suppression system called a so-called active stabilizer, and is a system in which the rigidity of the stabilizer bar is variable by the operation of an actuator. In the system of this section, when a steering operation with a high steering speed is performed, the actuator operation is limited to limit the change in roll rigidity. Even in this case, a predetermined roll restraining moment is generated. Can be made. Therefore, it is possible to avoid a situation in which a sufficient roll restraining moment cannot be generated due to a delay in control, and it is effective even when the turning state (the straight traveling state is also an ultimate aspect of the turning state) changes suddenly. Roll suppression is possible. Due to such advantages, the stabilizer system described in this section becomes a practical stabilizer system.

  The “stabilizer bar” included in the stabilizer system described in this section is not limited in shape, structure, or the like. For example, a structure that generates a roll restraining moment by being twisted can be used. Specifically, a structure that is similar to a stabilizer bar provided in a general stabilizer system that is not equipped with an actuator (hereinafter, sometimes referred to as “conventional stabilizer system” or “conventional system”) is adopted. In addition, as described later, the stabilizer bar included in the conventional system is divided into a pair of stabilizer bar members, and one stabilizer bar is configured by the divided pair of members. It is also possible to adopt a stabilizer bar having a simple structure.

  The “actuator” provided in the system of this section can be structured to change the stiffness of the stabilizer bar by operating it, displacing and deforming the stabilizer bar, or applying some force. is there. Here, “rigidity” means, for example, torsional rigidity (it can also be considered as an elastic force of the stabilizer bar). Further, “changing the rigidity” does not mean changing the rigidity as the physical property value of the stabilizer bar itself, but means changing the so-called apparent rigidity. Specifically, for example, the relative displacement amount of each end portion connected to each of the left and right wheels (strictly connected to a wheel holding member such as a suspension arm), and the roll restraining moment to be generated, This means that the magnitude of the roll restraining moment generated by the stabilizer bar is changed when the roll angle of a certain vehicle body is maintained at a certain angle.

  Further, the “actuator” may be operated with any driving force. For example, it is possible to employ an actuator having a structure that is operated by the hydraulic pressure generated by the hydraulic unit, and it is also possible to employ an actuator having a structure that is operated by an electric motor, as will be described later. Is possible. As a hydraulic drive actuator, a structure that functions as a cylinder device can be adopted. More specifically, a housing and a piston (a concept including a vane in the case of a rotary actuator) are provided, and the housing and the piston are moved relative to each other by controlling the fluid pressure filled in the fluid chamber. It is possible to adopt a structure that changes the rigidity of the stabilizer bar by operation. As will be described later, the electric actuator includes a housing, an electric motor held by the housing, and an output shaft that is rotatably held by the housing and rotated by the electric motor, and is supplied to the electric motor. It is possible to adopt a structure in which the housing and the output shaft are relatively rotated by controlling electric power, and the rigidity of the stabilizer bar is changed by the relative rotation.

  The location of the actuator is not particularly limited. For example, if the stabilizer bar is similar to the stabilizer bar provided in the conventional system described above, it is disposed between one end of the stabilizer bar and one wheel, and the end and the wheel It is possible to change the interval. Further, when the stabilizer bar has the pair of stabilizer bar members described above, the stabilizer bars are disposed between the pair of stabilizer bar members as described later, and the relative rotation angles thereof. It is also possible to change.

  The “control device” included in the aspect of this section employs, for example, a computer-based configuration, and performs active roll control, that is, the roll suppression moment generated by the stabilizer bar is appropriate according to the turning state of the vehicle. The actuator can be controlled to have a size that realizes a proper roll angle. Here, the “turning state” means, for example, what kind of roll moment the vehicle body is receiving. The turning state can be quantitatively expressed by a turning state amount (for example, lateral acceleration, yaw rate, etc.) indicating the turning state. In the active roll control, for example, a turning state amount is detected using a lateral acceleration sensor, a yaw rate sensor, or the vehicle traveling speed (may be a wheel rotational speed) detected by a vehicle speed sensor or the like and a steering amount sensor. The turning state amount is estimated on the basis of the steering amount (which may be the operation amount of the steering operation member or the steering amount of the wheel) detected by, and the detected turning state amount is estimated This can be executed by controlling the actuator so as to obtain an operation amount that can generate an appropriate roll restraining moment based on at least one of the determined turning state amounts.

  The “high-speed steering control unit” included in the control device is a specific functional unit that executes processing during high-speed steering of the control device. Whether or not it is during high-speed steering can be recognized based on the steering speed. The steering speed used for the authorization may be an operation speed of a steering operation member such as a steering wheel, or may be a steering speed of a wheel. The “threshold speed” can be set to a steering speed that the active roll control cannot follow. For example, in the case where the steering angular speed of the steering wheel is set as the steering speed, for example, when the threshold speed is set to 500 ° / second and the steering is performed with the operating angular speed exceeding the threshold speed, it is recognized that the steering speed is high. It is possible.

  The high-speed steering control unit executes high-speed steering control, that is, processing for bringing the actuator into a braking state as described above. The “braking state” means a state where the operation of the actuator is restricted. Specifically, in the case where a force that causes the actuator to be operated by the roll of the vehicle body (hereinafter sometimes referred to as “reverse input”) acts on the actuator, And a state that requires a considerably large force when the actuator is operated by an input. In short, the former is a state where the actuator is fixed, that is, a so-called locked state, and the latter is a state where the brake is applied. By setting the actuator in a braking state, a predetermined reaction force against reverse input can be generated, and a predetermined roll restraining moment can be generated by the stabilizer bar without performing active roll control on the actuator.

  In order to place the actuator in a braking state, for example, a mechanical mechanism device such as a lock device or a brake device using frictional force may be provided in the actuator, and these devices may be operated. Further, when the actuator is the cylinder device described above, the inflow and outflow of the working fluid into and out of the liquid chamber in the housing is prohibited by a shut-off valve or the like, or restricted by a flow restriction valve (for example, a throttle valve) or the like. Thus, the braking state of the actuator can be realized. Furthermore, when the actuator uses the driving force of the electric motor described above, the braking state of the actuator is changed by setting the electric motor to a braking state using a counter electromotive force, as will be described later. It is possible to realize.

  (2) The vehicle stabilizer system according to (1), wherein the high-speed steering control unit sets the actuator to a braking state so that the rigidity of the stabilizer bar is higher than a set height. .

  The mode described in this section is a mode that defines the lower limit of the rigidity of the stabilizer bar in the high-speed steering control. According to the aspect of this section, it is possible to generate a roll restraining moment that is greater than or equal to the set, without using active roll control. Specifically, the “stiffness above the set height” specifically means that the rigidity of the stabilizer bar is higher than the rigidity of the stabilizer bar when the system is assumed not to have an actuator, that is, the rigidity of the stabilizer bar in a conventional system. It is desirable that the rigidity is as follows. If configured so as to have such rigidity, it becomes possible to generate a roll restraining moment that is greater than the roll restraining moment that can be generated by a conventional system in high-speed steering control.

  (3) The vehicle stabilizer system according to (1) or (2), wherein the actuator has an electric motor and is operated by a driving force of the electric motor to change the rigidity of the stabilizer bar. .

  The mode described in this section is a mode in which the structure of the actuator is limited. An actuator having an electric motor has the advantage of being compact compared to the hydraulic drive actuator described above. If the actuator is configured to include a speed reducer that reduces and transmits the rotation of the electric motor, in particular, a harmonic gear mechanism (also called a harmonic drive mechanism (registered trademark), a strain wave gearing mechanism), a cycloid reduction mechanism The electric motor can be miniaturized by using a reduction gear having a large gear ratio (for example, meaning that the output rotational speed is small relative to the input rotational speed) employing a planetary gear mechanism having a multi-stage configuration. Further downsizing of the actuator can be achieved. “Electric motor” that can be used in the aspect of this section is not limited in its form, and includes various types of motors such as an induction motor, a synchronous motor, a stepping motor, and a reluctance motor, including a DC brushless motor described later. It is possible to adopt a type of motor, and in terms of operation, it may be a rotary motor or a linear motor. As will be described later, when the operation mode is changed, it is desirable that it can be easily performed.

  (4) The high-speed steering control unit sets the operating mode of the electric motor to a mode in which a braking state based on a braking force caused by the counter electromotive force of the electric motor is realized, thereby setting the actuator in a braking state. The vehicle stabilizer system according to item (3).

  The mode described in this section is a mode in which the braking state is realized by setting the operation mode of the electric motor to a predetermined mode when the actuator having the electric motor is employed. The “operation mode” of the electric motor referred to in this aspect is an operation mode determined by the energization mode and the power supply state of the electric motor, and the “energization mode” described here will be described in detail while illustrating later. Means a mode related to switching of each phase in energization from the control power source to the electric motor, connection between the input line of each phase of the electric motor and the control power source, relation between the input lines of each phase of the electric motor, etc. The “power supply state” means, for example, a state of whether or not power is supplied to the electric motor, how much power is supplied, at what timing and at what timing. . As will be exemplified later, the operation modes can be various modes depending on the energization mode and the power supply state, and each mode can have its own characteristics. By utilizing the characteristics of each mode and changing the operation mode of the electric motor, the characteristics of the stabilizer can be variously changed.

  In the mode of this section, the mode adopted in the high-speed steering control is not a mode for the purpose of the above-mentioned active roll control but a mode that can be called a “brake mode”, from the control power source to the electric motor. It is one form of the operation mode which does not supply the electric power. This brake mode can be considered as an operation mode employing an energization mode in which, for example, the input lines of the electric motor are connected to each other. When the phases are connected to each other without any resistance, that is, when they are short-circuited, a so-called short-circuit braking effect is obtained. This short-circuit braking can provide a relatively large braking effect even during braking by back electromotive force. Therefore, an effect close to locking the actuator can be obtained, and the function equivalent to or close to that of the stabilizer bar provided in the conventional system can be exhibited in the stabilizer bar. Further, when the phases are connected to each other via a resistor, a so-called buffer braking effect is obtained. Although this buffer braking has a smaller braking force than the short-circuit braking described above, it is possible to suppress heat generation of the electric motor by consuming a part of the counter electromotive force by a resistor provided outside. It becomes possible. As will be described in detail later, when an inverter including an inverter is adopted as the control power supply, this operation mode includes, for example, switching elements for at least one of a plus (high) side and a minus (low) side. , All can be realized by turning them on (closed state).

(5) The control device
A low-speed steering control unit that sets the operation mode of the electric motor to a mode in which the operation control of the actuator can be executed by changing the supply power when the steering speed is less than or equal to a set threshold speed. The vehicle stabilizer system according to (3) or (4).

  The mode described in this section is a mode in which the active roll control can be executed in the control when steering at a relatively low steering speed is performed, that is, in the low-speed steering control. The operation mode of the electric motor described in this section is a mode that can be referred to as a so-called “control mode”, and controls the amount of electric power supplied to the electric motor while switching the energization phase in energization of the electric motor. This is an operation mode for controlling the operation of the motor. According to the aspect of this section, active roll control is possible during low speed steering, and effective roll suppression is possible.

(6) The control device
When it can be assumed that the vehicle is not being steered, the operation mode of the electric motor is a mode in which a state in which a braking force due to the counter electromotive force cannot be obtained by blocking conduction between the phases of the electric motor is realized. The vehicle stabilizer system according to any one of (3) to (5), further including a non-steering control unit.

  The mode described in this section is, for example, a non-steering mode, specifically, when the vehicle is in a straight traveling state, the operation mode of the electric motor is a mode not intended for active roll control. This is a mode that can be called a “free mode”. The free mode is a form of an operation mode in which power is not supplied from the control power supply to the electric motor. Generally speaking, for example, the connection between the input line of each phase of the electric motor and the control power supply is cut off. Such an operation mode, in other words, an operation mode in which each phase of the electric motor is in an open state can be considered. In the free mode, no back electromotive force is generated in the electric motor, and the braking effect is hardly obtained. Therefore, if this operation mode is adopted, the stabilizer bar is in a state in which it can hardly exhibit the roll restraining moment, and the vehicle can be regarded as having no stabilizer system. Therefore, under this operation mode, for example, independence on the left and right sides with respect to the reverse input when the vehicle is on a single wheel is secured, and the riding comfort of the vehicle can be improved. As will be described in detail later, when a control power supply including an inverter is employed, this operation mode is realized by, for example, turning off all the switching elements of each phase (open state). It is possible.

  (7) The vehicle stabilizer system according to any one of (3) to (6), wherein the electric motor is a DC brushless motor.

Since the DC brushless motor has good controllability, the DC brushless motor is suitable as a drive source for the actuator provided in the active stabilizer system. In addition, there is an advantage that the characteristics that should be possessed in each of the three operation modes described above are realized in a good state by changing the energization mode and the power supply state.
(8) The stabilizer system includes a control power supply for the electric motor including an inverter, and an operation mode of the electric motor is determined by an operation state of a switching element included in the inverter (3 The vehicle stabilizer system according to any one of items) to (7).

  A power source including an inverter is suitable as a control power source for an active stabilizer system because the operation control of the electric motor can be easily and accurately performed. Further, according to the inverter, each of the above three control modes can be easily realized by changing the combination of ON / OFF states of switching elements such as FETs provided for each phase. It is.

(9) The stabilizer bar is
A torsion bar portion each extending in the vehicle width direction, an arm portion extending from the end of the torsion bar portion so as to intersect the torsion bar portion, and having a tip portion connected to one of the left and right wheels; Comprising a pair of stabilizer bar members having
Any one of the items (1) to (8), wherein the actuator is configured to change the rigidity of the stabilizer bar by changing a relative rotation angle of the torsion bar portion of the pair of stabilizer bar members. The vehicle stabilizer system described in 1.

  The mode described in this section is a mode in which the structure of the stabilizer bar is specifically limited, and the relationship between the stabilizer bar and the actuator is specifically limited. According to the aspect described in this section, the active roll control can be efficiently performed. In addition, when the actuator is in a braking state during high-speed steering, a predetermined roll restraining moment can be easily generated.

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

<Overall configuration of stabilizer system>
FIG. 1 conceptually shows a vehicle stabilizer system 10 according to an embodiment of the present 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 a wheel holding member (see FIG. 2) that holds the left and right wheels 16 at both ends. 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 as to be relatively rotatable. Generally speaking, in the stabilizer device 14, the actuator 30 causes the left and right stabilizer bar members 22 and 24 to rotate relative to each other. Thus (refer to the arrows and dotted arrows in the figure), the 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. This suspension device 38 is of a generally well-known double wishbone type, and has an upper arm 42 as a wheel holding member having one end portion rotatably connected to the vehicle body and the other end connected to the wheel 16. A lower arm 44 is provided. 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”). Each of the shock absorber 46 and the spring 48 is connected to a vehicle body side member and a wheel side member. 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 bar members described above (in FIG. 2, one of the right stabilizer bar member 22 and the left stabilizer bar member 24 is It is shown). 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, an end portion (an end portion opposite to the torsion bar portion 60 side) of the arm portion 62 is connected to a stabilizer bar connecting portion 68 provided in the lower arm 44 so as to be relatively rotatable with the stabilizer bar connecting portion 68.

  As schematically shown in FIG. 3, the actuator 30 includes an electric motor 70 and a speed reduction mechanism 72 that reduces the rotation of the electric motor 70. The electric motor 70 and the speed reduction mechanism 72 are provided in a housing 74 that is an outer shell member of the actuator 30. The housing 74 is held by the stabilizer device mounting portion 64 by the housing holding member 76 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 of the output shaft 82 in the housing 74 is connected to the speed reduction mechanism 72 as will be described in detail later.

  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 mechanism 72 includes a wave generator (wave generator) 90, a flexible gear (flexspline) 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. Since the harmonic gear mechanism has a known configuration, the detailed illustration of the speed reduction mechanism 72 is omitted, and the description will be limited to this level.

  From the above configuration, when the electric motor 70 is rotated, that is, when the actuator 30 is operated, the torsion bar portions 60 of the right stabilizer bar member 22 and the left stabilizer bar member 24 are relatively rotated, and the right stabilizer is provided. The stabilizer bar 20 that can be considered as one stabilizer bar constituted by the bar member 22 and the left stabilizer bar member 24 is twisted. The force generated by this twisting acts as a force for approaching or separating the left and right wheels 16 and the vehicle body. That is, the stabilizer device 14 is configured to change the rigidity of the stabilizer bar 20 by the operation of the actuator 30.

  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 is mainly composed of an encoder in the actuator 30, and the detected value is used for switching the energized phase of the electric motor 70 and the relative values of the left and right stabilizer bar members 22, 24. As an index of the rotation angle (relative rotation position), it is used for control of the actuator 30, that is, roll suppression control by the stabilizer device 14.

  Electric power is supplied from a control power source to the electric motor 70 included in the actuator 30. As shown in FIG. 1, the stabilizer system 10 includes a battery 102 and two inverters 104 connected to the battery 102. The inverter 104 functions as a drive circuit, and electric power is supplied from each of the two inverters 104 to the electric motor 70 included in each of the two stabilizer devices 14. That is, the battery 102 and one inverter 104 constitute a control power source for each electric motor 70.

  As shown in FIG. 1, the stabilizer system 10 includes a stabilizer device 14, specifically, a stabilizer electronic control unit (stabilizer ECU) 110 (hereinafter simply referred to as “ECU 110”) that is a control device that controls the operation of the actuator 30. There is). 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 referred to as “vehicle speed”), and an actual lateral acceleration that is a lateral acceleration actually generated in the vehicle body A lateral acceleration sensor 124 is connected to detect. (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 operation of the actuator 30 by controlling the inverter 104. The ROM included in the computer of the ECU 110 stores programs such as a roll suppression control program and an operation mode switching program, which will be described later, and various data related to the control of the stabilizer device 14.

<Functional configuration of control device>
If the function of ECU110 which is a control apparatus of the stabilizer apparatus 14 is expressed conceptually, it will become like FIG. The ECU 110 is an operation mode switching unit 130 that switches the operation mode of the electric motor 70 based on the steering speed and the like, and a high-speed steering control unit 132 that is three functional units that selectively function according to the switching of the operation mode switching unit 130. , A low-speed steering control unit 134 and a non-steering control unit 136. The high-speed steering control unit 132 is a functional unit that causes the electric motor 70 to be in a braking state during high-speed steering in which the steering speed is equal to or higher than the threshold speed, and the low-speed steering control unit 134 is during low-speed steering that the steering speed is lower than the threshold speed. The non-steering control unit 136 is a functional unit that controls and operates the electric motor 70. The non-steering control unit 136 is a functional unit that hardly obtains a braking force when the vehicle is not being steered. The low-speed steering control unit 134 includes an operation control unit 138 for actively suppressing the roll of the vehicle body by controlling the electric motor 70 based on the vehicle speed, the actual lateral acceleration, and the like. Yes. Detailed functions of each functional unit described above will be described later in the description of processing by the roll suppression control program and the operation mode switching program executed by the ECU 110.

<Electric motor operation mode>
In the present stabilizer system 10, the electric motor 70 provided in the actuator 30 of the stabilizer device 14 is operable in three operation modes, and 1 selected based on the conditions set from the three operation modes. Operated in two operating modes. The operation mode is determined by the energization mode of the electric motor 70 and the power supply state to the electric motor 70, and the three operation modes are different from each other in at least one of the energization mode and the power supply state. . The operation mode is switched by switching the switching element of the inverter 104 ON / OFF. As shown in FIG. 5, the electric motor 70 is a Δ-connected three-phase DC brushless motor, and the inverter 104 is high (plus) side, low (minus) for each phase (U, V, W). Side switching elements (which are FETs) (hereinafter referred to as “UHC”, “ULC”, “VHC”, “VLC”, “WHC”, “WLC”). I will call it). The operation mode is switched by switching each of the six switching elements ON / OFF.

  Specifically, the three operation modes are a “control mode” in which the operation of the electric motor 70 can be actively controlled, and an operation mode in which the operation control of the electric motor 70 is not executed. It consists of a “brake mode” that realizes a braking state by power and a “free mode” that realizes a state in which almost no braking force can be obtained. Each operation mode will be described below with reference also to FIG. 6 showing a switching pattern of the switching elements of the inverter 104.

i) Control Mode The control mode is an operation mode in which electric power is supplied to the electric motor 70 under a power supply mode in which the electric motor 70 can be controlled. In the control mode, each switching element UHC, ULC, VHC is shown in FIG. 6 as shown in the case of right rotation (CW rotation) and left rotation (CCW rotation) by a so-called 120 ° energizing rectangular wave drive. , VLC, WHC, WLC are switched according to the rotation angle θ of the electric motor 70. More specifically, the pattern in the figure is a pattern with an electrical angle of 60 °, and the electric motor 70 is a three-phase 6-pole motor. Therefore, every 20 ° of motor rotation angle corresponding to an electrical angle of 60 °. The energization pattern is sequentially changed. Under such an energization mode, the switching elements ULC, VLC, WLC existing on the low side are duty controlled. Duty control here is control which changes the electric energy supplied to the electric motor 70 by changing the ratio (Duty ratio) of the pulse on time and pulse off time by PMW (Pulse Width Modulation). “1 *” in FIG. 6 indicates this. Incidentally, the switching timing of the energized phase and the pulse on / pulse off timing are controlled by the phase switching circuit based on the signal of the motor rotation angle sensor 100 provided in the actuator 70.

  As described above, the control mode is a mode in which the rotation direction of the electric motor 70 and the amount of electric power supplied to the electric motor 70 can be controlled, and normal roll suppression control executed by the system 10, that is, active roll control. Is performed in this control mode. The active roll control will be described in detail later. According to the active roll control, it is possible to control the actuator 30 to actively change the stiffness of the stabilizer bar 20.

ii) Brake mode In the brake mode, each phase of the electric motor 30 is connected to each other. Specifically, as shown in FIG. 6, all of the high-side switching elements UHC, VHC, and WHC are turned on (closed state). Due to the switching elements UHC, VHC, WHC and the reflux diodes arranged in parallel to them, the phases of the electric motor 70 are in a state where they are short-circuited with each other. As a result, when there is a reverse input to the stabilizer bar 20, a large back electromotive force is generated in the electric motor 70, and a relatively large braking force is applied to the electric motor 70. Therefore, the actuator 30 is almost locked with respect to a reverse input at a relatively high speed, and the pair of stabilizer bar members 22 and 24 act integrally. That is, in this mode, the stabilizer device 14 is brought into a state close to a system having no actuator, that is, a stabilizer bar in a conventional system, and the stabilizer bar 20 has a corresponding rigidity as in the stabilizer bar of the conventional system. Will be demonstrated.

iii) Free mode In the free mode, the power supply to each phase of the electric motor 70 is cut off. Specifically, as shown in FIG. 6, all of the switching elements UHC, ULC, VHC, VLC, WHC, and WLC are turned off (open state). As a result, it is almost as if the connection between each phase of the electric motor 70 and the inverter 104 is disconnected. Therefore, even when there is a reverse input to the stabilizer bar 20, no back electromotive force is generated in the electric motor 70, and only a braking force resulting from cogging torque, sliding resistance, etc. is obtained. It will be in a state that does not demonstrate. In other words, the pair of stabilizer bar members 22 and 24 are allowed to relatively rotate in a relatively free state, the stabilizer bar 20 does not exhibit rigidity, and the stabilizer device 14 does not function as a stabilizer device. . In this mode as well, a regenerative circuit is formed via the freewheeling diode, and the electric motor 70 itself becomes a generator, but because the regenerative current flows only after the electric motor 70 generates power to a voltage higher than the power supply voltage, Almost no regenerative current flows, and the braking effect due to regeneration is substantially not obtained.

<Switching operation mode of electric motor>
Switching of the operation mode of the electric motor 70 is performed by the ECU 110 executing an operation mode switching program shown by a flowchart in FIG. This program is executed with an extremely short time interval (for example, 10 to several tens of msec) while the ignition switch is in the ON state (in parallel with the roll suppression program described later by time division). May be executed). Below, the mode of the operation mode switching by this program is demonstrated along a flowchart.

  According to the processing of this program, first, in step S11 (hereinafter abbreviated as “S11”, the same applies to the following steps), the operation angle δ of the steering wheel is acquired based on the detected value of the operation angle sensor 120. The Next, in S12, it is determined whether or not the vehicle is traveling straight. The operation angle δ acquired by the previous execution of this program is stored for a set time (for example, 0.3 sec), and in this embodiment, the operation angle δ within the set time is a preset neutral position. It is determined that the vehicle is traveling straight when it is within a certain range including. In that case, the process proceeds to S13 and the operation mode is determined to be “free mode”. A signal for setting the free mode to the inverter 104 is output, and one execution of this program is completed. In the present embodiment, when the vehicle is in a straight traveling state, for example, the pair of stabilizer bar members 22 and 24 are relatively rotated in a relatively free state with respect to a reverse input when the vehicle is on a single wheel. Is permitted, independence of the left and right sides is ensured, and the ride comfort of the vehicle is improved.

On the other hand, if there is a period during which the operation angle δ is out of the neutral position within the set time, it is determined that the vehicle is not in a straight traveling state, and the determination in S12 is NO. Next, the processing proceeds to S14, where the operation angular velocity dδ, which is the difference between the operation angle δ acquired in the program executed immediately before and the operation angle δ acquired this time, is acquired as the steering speed. Next, in S15, whether the operation angular velocity d? Do preset threshold speed d? ₁ is smaller than or not. The threshold speed dδ ₁ is set to an operation angular speed (for example, 500 ° / second) that cannot be followed by active roll control. When manipulating angular velocity d? Is a threshold speed d? ₁ is smaller than, the flow advances to S16, operation modes are determined to "control mode". Specifically, at the time of low-speed steering, active roll control is executed by executing a roll suppression program described later. This completes one execution of the program.

On the other hand, when the operation angular velocity d? Is the threshold speed d? ₁ or more, the operation mode proceeds to step S17 are determined to "brake mode", that effect the signal is output to the inverter 104. This completes one execution of the program. In the “brake mode”, the electric motor 70 is brought into a braking state by the braking force caused by the counter electromotive force, so that the actuator 30 is almost locked with respect to the reverse input at a relatively high speed. In the active roll control in the “mode”, it is possible to avoid a situation in which a sufficient roll restraining moment cannot be generated due to a delay in control, and effective roll restraining can be performed.

  As is apparent from the above description, among the portions that execute the operation mode switching program of the ECU 110, the portions that execute S11, S12, S14, and S15 constitute the operation mode switching portion 130. Further, the part that executes S13 constitutes the non-steering control unit 136, the part that executes S16 constitutes the low-speed steering control unit 134, and the part that executes S17 constitutes the high-speed steering control unit 132. Yes.

<Active roll control>
In the present stabilizer system 10, active roll control, that is, control for actively suppressing the roll of the vehicle body is performed under the control mode. The active roll control is performed by executing a roll suppression control program shown in the flowchart of FIG. 8 at a short time interval (for example, ten to several tens of milliseconds) in the ECU 110. Incidentally, the roll suppression control program is executed only while the operation mode of the electric motor 70 is set to the control mode, that is, only during low-speed steering. The active roll control will be briefly described below with reference to the flowchart of FIG. Note that a portion of the ECU 110 that executes the roll suppression control program corresponds to the operation control unit 142.

In the active roll control, first, in S21, the vehicle speed v is acquired based on the detection value of the vehicle speed sensor 122. Next, in S22, an operation angle δ of the steering wheel is acquired as a steering amount based on a detection value of the operation angle sensor 120. In subsequent S23, the estimated lateral acceleration Gy _C is estimated based on the vehicle speed v and the operation angle δ. Regarding the estimated lateral acceleration Gy _C , a map using the vehicle speed and the operation angle as parameters is created in advance based on the vehicle characteristics, and the ECU 110 stores the data. In S23, the estimated lateral acceleration Gy _C is estimated by referring to the map data.

Next, in S24, an actual lateral acceleration Gy that is an actual lateral acceleration generated in the vehicle body is acquired based on a detection value of the lateral acceleration sensor 124. Next, in S25, the control lateral acceleration Gy ^{* that} is an index for the roll suppression control is determined based on the estimated lateral acceleration Gy _C that has been estimated and the acquired actual lateral acceleration Gy. Specifically, the following formula:
Gy ^* = K ₁ · Gy _C + K ₂ · Gy
Determined according to. Here, K ₁ and K ₂ are gains, and are variables having parameters such as vehicle speed and steering speed.

Subsequently, in S26, the target motor rotation angle θ ^{* of} the electric motor 70 is determined based on the determined control lateral acceleration Gy ^* . Specifically, based on the control lateral acceleration Gy ^* , the rigidity of the stabilizer bar 20 that can resist the roll moment generated by the control lateral acceleration Gy ^* is known, and a pair of stabilizer bar members 22 that can obtain the rigidity, The relative rotation angle of 24 is known. Since the relative rotation angle can be associated with the rotation angle of the electric motor 70 from the structure of the actuator 30 described above, the target motor rotation angle θ ^* , which is the rotation angle of the target electric motor 70, is determined. Can do it. The ECU 110 stores map data of the target motor rotation angle θ ^{* using} the control lateral acceleration Gy ^* as a parameter. In practice, the target motor rotation angle θ ^* is determined with reference to the map data. The

Based on the determined target motor rotation angle θ ^* , rotation control of the electric motor 70 is performed in S27. Specifically, based on the motor rotation angle deviation Δθ, which is the deviation between the actual motor rotation angle θ detected by the motor rotation angle sensor 100 and the target motor rotation angle θ ^* , the rotation direction of the electric motor 70 and the electric motor 70 are determined. Is supplied to the inverter 104 as a command. The inverter 104 operates so as to realize the commanded rotation direction and supply current amount, and the rotation control of the electric motor 70 is performed.

The description of the active roll control is merely an outline of the control content in a certain control mode. The active roll control can be employed with various types of control already known. Further, the present suspension system 10 is provided with two stabilizer devices 14, and the above-described control is performed for each of the two stabilizer devices 14. In practice, complicated processing is executed, such as determining the target motor rotation angle θ ^* , which is the control target value of each of them, by taking into account the roll rigidity distribution of the front and rear wheels, etc. Since the control itself is not directly related to the present invention, the description thereof is limited to the simple one as described above.

  In this embodiment, the mode in which the actuator is actuated by the electric motor has been described. However, the actuator may be actuated by any driving force, and an actuator that is actuated by hydraulic pressure may be employed. It is.

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 block diagram which shows notionally the function of the stabilizer electronic control unit (ECU) with which the stabilizer system of FIG. 1 is provided. FIG. 4 is a circuit diagram in a state where the inverter included in the stabilizer system of FIG. 1 and the electric motor shown in FIG. 3 are connected. It is a table | surface which shows the switching state of the energization phase by the inverter of FIG. 5 in each operation mode of an electric motor. It is a flowchart which shows the operation mode switching program performed in the stabilizer system of FIG. It is a flowchart which shows the roll suppression control program performed in the stabilizer system of FIG.

Explanation of symbols

  10: Vehicle stabilizer system 14: Stabilizer device 20: Stabilizer bar 22: Right stabilizer bar member 24: Left stabilizer bar member 30: Actuator 70: Electric motor 72: Deceleration mechanism 74: Housing 100: Motor rotation angle sensor 104: Battery 110 : Stabilizer electronic control unit (control device) 120: Operating angle sensor 122: Vehicle speed sensor 130: Operation mode switching unit 132: High speed steering control unit 134: Low speed steering control unit 136: Non-steering control unit 138: Operation control unit

Claims (3)

A stabilizer system for a vehicle comprising a stabilizer bar having both ends connected to the left and right wheels, an actuator for changing the rigidity of the stabilizer bar by its own operation, and a control device for controlling the operation of the actuator. Because
The control device includes a high-speed steering control unit that sets the actuator to a braking state in which the operation of the actuator is restricted when the steering speed exceeds a set threshold speed. Stabilizer system.   The actuator has an electric motor and is operated by a driving force of the electric motor to change the rigidity of the stabilizer bar, and the high-speed steering control unit sets the operation mode of the electric motor to the electric motor. The vehicle stabilizer system according to claim 1, wherein the actuator is brought into a braking state by setting a mode in which a braking state by a braking force caused by the back electromotive force is realized. The said stabilizer system is provided with the control power supply of the said electric motor comprised including an inverter, The operation mode of the said electric motor was set as the structure determined by the operating state of the switching element which the inverter has. Vehicle stabilizer system.

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