JP2010284985A - Damping force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a damping force control device for controlling a damping force characteristic of a damper so as to minimize reduction in the vibration restraining effect of a sprung member, even when failure is caused in an active stabilizer. <P>SOLUTION: In this damping force control device, when operation lock failure of locking operation of a rear wheel side stabilizer actuator 23R is caused, an R system and a W system are corrected to an R<SB>b</SB>system and a W<SB>b</SB>system by substituting rear wheel side stabilizer generation force in the R system and the W system used when calculating respective request damping forces, with rear wheel abnormal time generation force F<SB>C_r</SB>(S230). The respective wheel request damping forces are calculated by taking into consideration proper force actually generated by the active stabilizer by this correction. Reduction in the vibration restraining effect of the sprung member HA is restrained even in the operation lock failure by controlling a damping force characteristic of the respective dampers based on the respective wheel request damping forces calculated in this way. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a damping force control device that controls damping force characteristics of a damper of a vehicle suspension device.

  In general, a vehicle is provided with four suspension devices corresponding to front, rear, left and right wheels. Damping force control devices that variably control the damping force characteristics of dampers of these suspension devices are known. When variably controlling the damping force characteristics of the damper, a single-wheel control system that independently controls the damping force characteristics of each damper, or three-way mode vibration (heave vibration, roll vibration, pitch vibration) of the sprung member (vehicle body) For example, a mode control method for controlling the damping force characteristics of the four dampers in a coordinated manner is applied. Since the mode control system controls the damping force characteristics of each damper based on the overall behavior of the sprung member, vibration in each direction (heave direction, roll direction, pitch direction) of the sprung member is effective. Can be suppressed.

  Incidentally, the vibration in the roll direction of the vehicle is suppressed by controlling the damping force characteristic of each damper according to the mode control method as described above, but is also suppressed by the active stabilizer. The active stabilizer is a roll rigidity control device that controls roll rigidity by twisting a torsion bar that connects the right wheel side and the left wheel side of the vehicle with an actuator. The roll is suppressed by appropriately changing the roll rigidity according to the roll of the vehicle and controlling the force generated by the stabilizer (stabilizer generating force). Various control methods related to this active stabilizer have been proposed.

  Patent Document 1 discloses an active stabilizer that can correct the posture of a vehicle body by a hydraulic cylinder attached to the active stabilizer when the vehicle body is tilted due to an actuator malfunction of the active stabilizer. Patent Document 2 discloses that when the active stabilizer can generate only a force smaller than the force that should be generated by an abnormality, a command to increase the damping coefficient of the damper of the suspension device is transmitted from the stabilizer ECU to the suspension ECU. An active stabilizer that compensates for the deficient force by the damping force of the damper is disclosed. Patent Document 3 discloses a control mode in which the energization mode for the actuator of the active stabilizer is controlled depending on the situation and the roll of the sprung member is actively controlled according to the running state. An active stabilizer that can be assigned to a standby mode with excellent responsiveness, a brake mode for locking the actuator, and a free mode in which the actuator is in a free state and no force is generated is disclosed.

JP 2005-125834 A JP 2006-021742 A JP 2006-188080 A

  When both the damping force control device and the active stabilizer are attached to the vehicle, the control of the damping force characteristic of the damper by the damping force control device and the control of the roll rigidity by the active stabilizer are performed separately. For this reason, when the suppression control of the roll by control of the damping force characteristic of a damper and the suppression control of the roll by control of the roll rigidity of a stabilizer interfere, there exists a possibility that the suppression effect of the roll of a sprung member may be impaired.

  In addition, when both the damping force control device and the active stabilizer are attached to the vehicle, if an operation abnormality occurs in the active stabilizer, the abnormality affects the control of the damping force characteristic of the damper by the damping force control device. Effect. As a result, the effect of suppressing the vibration of the sprung member (particularly the vibration in the roll direction) by controlling the damping force characteristic of the damper is reduced, leading to a deterioration in riding comfort.

  The present invention has been made to address the above-described problem, and a damping force control device in which a reduction in roll suppression effect caused by interference between damping force characteristic control of a damper and roll stiffness control by an active stabilizer is suppressed. The purpose is to provide. It is another object of the present invention to provide a damping force control device that controls a damping force characteristic of a damper so that a reduction in the suppression effect of the vibration of the sprung member can be suppressed as much as possible even when an abnormality occurs in the active stabilizer. .

  A feature of the present invention is a damping force control device that is applied to a vehicle equipped with an active stabilizer having an actuator and controls damping force characteristics of a damper of a suspension device attached to each wheel position of a sprung member. The roll that is the control target value of the heave demand damping force that is the control target value of the damping force acting in the heave direction of the sprung member and the control target value of the damping force that acts in the roll direction of the sprung member so as to suppress the vibration of the member A mode required damping force calculating means for calculating a required damping force and a pitch required damping force which is a control target value of the damping force acting in the pitch direction of the sprung member, and a heave calculated by the mode required damping force calculating means. Based on the required damping force, the required roll damping force, the required pitch damping force, and the stabilizer generating force generated by the active stabilizer, Each wheel required damping force calculating means for calculating each wheel required damping force which is a control target value of the damping force generated by the damper, and each wheel required damping force calculated by each wheel required damping force calculating means Based on this, a damping force control device for controlling the damping force characteristics of each damper is provided.

  According to the damping force control device of the present invention, based on the heave demand damping force, the roll demand damping force, the pitch demand damping force calculated by the mode demand damping force calculation means, and the stabilizer generating force generated by the active stabilizer, Each wheel required damping force, which is a control target value of the damping force generated by each damper, is calculated. Based on the calculated required damping force for each wheel, the damping force characteristic of each damper is controlled.

  Since the stabilizer generated force is taken into account when calculating the required damping force for each wheel, interference between the damping force characteristic control of the damper by the damping force control device and the roll stiffness control by the active stabilizer is prevented. Therefore, it is possible to suppress a decrease in the roll suppression effect due to interference between the damping force characteristic control of the damper and the roll stiffness control by the active stabilizer.

In the above invention, the suspension device is attached to each of the wheel positions of the sprung member (vehicle body), that is, the right front wheel position, the left front wheel position, the right rear wheel position, and the left rear wheel position. Therefore, each wheel required damping force calculation means calculates each wheel required damping force for each damper of the suspension device mounted at these four locations, that is, the right front wheel side required damping force F _{req_fr} , the left front wheel side required damping force F _{req_fl} , The right rear wheel side required damping force _{Freq_rr} and the left rear wheel side required damping force _{Freq_rl} are calculated.

The mode required damping force calculating means may calculate each mode required damping force (heave required damping force, roll required damping force and pitch required damping force) based on a desired control theory relating to vibration suppression control. . For example, by applying a nonlinear _H∞ control theory to a four-wheel model of a vehicle, it is possible to calculate a heave demand damping force, a roll demand damping force, and a pitch demand damping force. The four-wheel model may be a model that does not consider the force generated by the active stabilizer (stabilizer generating force). In other words, the mode required damping force calculation means obtains each mode required damping force using a control model designed on a model base without a stabilizer, and then each wheel required damping force calculation means considers the stabilizer generating force for each mode. The required damping force may be distributed to each wheel required damping force.

  In this case, each wheel required damping force calculating means includes the heave required damping force, roll required damping force, pitch required damping force, each wheel required damping force and the stabilizer generating force calculated by the mode required damping force calculating means. Each wheel required damping based on a relational expression representing the balance of force between the wheel and the restraint conditional expression representing the relation between the stabilizer generating force restrained by a predetermined condition and each wheel required damping force. It is better to calculate the force. Further, the relational expression is expressed as a balance between the heave-required damping force relation of each wheel and the balance between the required force of each wheel and the required damping force of each wheel. It is preferable that the relationship between the pitch-represented wheel damping force relationship and the roll-required damping force relationship between the roll requested damping force, the wheel requested damping force, and the stabilizer generating force is balanced. Further, the constraint conditional expression may represent a relationship between the stabilizer generating force that is constrained by a condition that the torsional force of the sprung member is zero and the required damping force for each wheel.

  In order to calculate the four required damping forces for each wheel, each mode required damping force (heave required damping force, pitch required damping force and roll required damping force), each wheel required damping force, and stabilizer generating force Four expressions representing the relationship are required. Therefore, heave-each wheel required damping force relational expression, pitch-each wheel required damping force relational expression, roll-each wheel required damping force relational expression, and a constraint condition expression representing the relationship between the stabilizer generating force and each wheel required damping force. Each wheel required damping force can be calculated by using a total of four equations. In addition, by calculating the required damping force for each wheel using the above four formulas and controlling the damping force characteristics of each damper based on the calculated required damping force for each wheel, interference with the roll stiffness control of the active stabilizer is prevented. The vibration of the sprung member can be effectively suppressed while preventing.

  Further, each wheel required damping force calculating means rotates the active stabilizer when the operation of the actuator is locked when an operation lock abnormality that locks the operation of the actuator occurs in the active stabilizer. It is preferable to calculate the required damping force for each wheel in consideration of the lock angle that is an angle. In this case, each wheel required damping force calculating means is configured to cause the active stabilizer at the time when the operation of the actuator is locked when an operation lock abnormality in which the operation of the actuator is locked occurs in the active stabilizer. Based on a lock angle that is a rotation angle, an abnormality generation force calculation means that calculates an abnormality generation force that is a stabilizer generation force generated by the active stabilizer that is the operation lock abnormality, and an abnormality generation force calculation means It is preferable to include a correction unit that corrects the relational expression and the constraint condition expression based on the calculated abnormality-generated force. More preferably, the abnormality generation force calculation means sets the twist amount when the active stabilizer is twisted further from the reference state, with the twist state of the active stabilizer having the rotation angle being the lock angle as a reference state. Based on this, it is preferable to calculate the abnormal force.

  When the operation of the actuator of the active stabilizer is locked, that is, when the actuator is fixed, the active stabilizer cannot change the roll rigidity. Therefore, the state that is twisted by the rotation angle (lock angle) of the active stabilizer at the time of locking (at the time of locking) becomes the reference state (neutral state) of the active stabilizer, and the active stabilizer is further activated from the reference state by road surface input or centrifugal force. When twisted, the active stabilizer generates a stabilizer generating force as a restoring force against torsion. In other words, the active stabilizer in which the operation lock abnormality has occurred has a function equivalent to that of a conventional stabilizer, and generates a force when further twisted from the state based on the state at the time of operation lock.

  According to the above invention, the abnormal-time generated force calculation means calculates the abnormal-time generated force, which is the stabilizer generated force generated by the active stabilizer in which the operation lock abnormality has occurred, based on the lock angle. Specifically, the force generated at the time of abnormality is calculated based on the amount of twist when the active stabilizer is twisted from the reference state with the twist state of the active stabilizer whose rotation angle is the lock angle as the reference state. Then, each relational expression and constraint condition expression used in calculating each wheel required damping force are corrected based on the calculated abnormality generated force. Specifically, each formula is corrected by replacing the stabilizer generating force included in each relational expression and the constraint condition expression with the abnormal generating force. Thereby, even when the operation lock abnormality has occurred in the active stabilizer, the vibration of the sprung member is suppressed in consideration of an appropriate stabilizer generating force generated by the active stabilizer (abnormal force generating force). Therefore, even when the active stabilizer is abnormal, a decrease in the effect of suppressing the vibration of the sprung member can be suppressed.

  In general, an active stabilizer has a pair of torsion bars that are relatively twisted by an actuator, and a pair of arms that are connected to respective end portions of the pair of torsion bars and are connected to left and right unsprung members. The relative rotation angle of the pair of torsion bars twisted by the actuator is the rotation angle of the active stabilizer. When an operation lock abnormality occurs, this rotation angle is fixed at a predetermined angle (lock angle). When the active stabilizer is further twisted from this locked state, the rotation angle of the active stabilizer (relative rotation angle of the torsion bar) does not change with the lock angle, but the relative rotation angle of the pair of arms changes according to the amount of twist. . That is, the amount of twist is represented by the difference between the relative rotation angle and the lock angle of the pair of arms. Therefore, the abnormal force generated by the active stabilizer, which is an operation lock abnormality, can be estimated based on the difference between the relative rotation angle and the lock angle of the pair of arms. Further, the relative rotation angle of the pair of arms can be estimated from the roll amount of the sprung member, and the roll amount of the sprung member is determined by the amount of relative displacement between the sprung-road surface at the right wheel position of the sprung member and the position of the left wheel. It is represented by the difference (difference in the left / right stroke amount) with the relative displacement between the sprung and the road surface. Therefore, the abnormality generated force calculation means calculates the abnormality generated force based on the difference between the sprung-road relative displacement amount at the right wheel position of the sprung member and the sprung-road relative displacement amount at the left wheel position. Can be calculated.

  Further, the correction means may correct the relational expression and the constraint condition expression so that the stabilizer generating force becomes zero when an operation-free abnormality in which the active stabilizer idles occurs. . Since the active stabilizer does not function when an operation free abnormality has occurred in the active stabilizer, it is not necessary to consider the force generated by the active stabilizer in the damping force control. Therefore, in this case, each mode requirement attenuation calculated based on the model without the active stabilizer by correcting each relational expression and the constraint condition expression so that the stabilizer generating force generated by the active stabilizer becomes 0 by the correcting means. The force is distributed as it is to each wheel required damping force. Note that the operation-free abnormality is an abnormality that causes the active stabilizer to idle as described above. When such an abnormality occurs, the active stabilizer cannot exhibit its own stabilizer generating force and is restored even if it is twisted by an external input. I cannot show my strength.

  The active stabilizer includes at least a front wheel side active stabilizer connected to the right front wheel and the left front wheel of the vehicle or a rear wheel side active stabilizer connected to the right rear wheel and the left rear wheel of the vehicle. Is good. According to this, the damping force characteristic of each damper can be controlled in consideration of the front wheel side stabilizer generating force generated by the front wheel side active stabilizer and / or the rear wheel side stabilizer generating force generated by the rear wheel side active stabilizer. . In addition, even when an operation lock abnormality or an operation free abnormality has occurred in each active stabilizer, the correction means corrects the stabilizer generating force for each active stabilizer so that the appropriate damping force required for each wheel is obtained. Can be calculated.

It is the schematic showing the suspension apparatus and active stabilizer which were mounted in the vehicle, and the control apparatus (ECU) which controls these suspension apparatuses and active stabilizer. It is the schematic which shows the structure of a suspension apparatus. It is a figure which shows roughly the input-output structure of suspension ECU. It is the figure which divided and represented suspension ECU for every function. It is a flowchart which shows the flow of a mode request | requirement damping force calculation process. It is a flowchart which shows a part of flow of each wheel request | requirement damping force calculation process. It is a flowchart which shows a part of flow of each wheel request | requirement damping force calculation process. It is a flowchart which shows a part of flow of each wheel request | requirement damping force calculation process. It is a flowchart which shows a part of flow of each wheel request | requirement damping force calculation process. It is a figure showing the four-wheel model of a vehicle. It is a block diagram of a generalized plant. It is the table | surface which put together the diagnostic result of the operating state of an active stabilizer. It is the schematic of the active stabilizer in which the operation lock abnormality has generate | occur | produced. It is the figure which looked at the active stabilizer of FIG. 10 from the arrow direction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a suspension device and an active stabilizer mounted on a vehicle, and a control device (ECU) that controls the suspension device and the active stabilizer. As shown in the figure, four suspension devices (a right front wheel side suspension device 10FR, a left front wheel side suspension device 10FL, a right rear wheel side suspension device 10RR, and a left rear wheel side suspension device 10RL) are attached to the vehicle. Yes. These suspension devices are provided between the sprung member HA and the unsprung member LA of the vehicle. The unsprung member LA is constituted by a knuckle connected to a wheel including a tire, a lower arm having one end connected to the knuckle, and the like, and supports the suspension device 10. The sprung member HA is a member supported by the suspension device 10 and includes the vehicle body.

  The right front wheel side suspension device 10FR is connected to the right front side (right front wheel position) of the sprung member HA, and the left front wheel side suspension device 10FL is connected to the left front side (left front wheel position) of the sprung member HA, and the right rear side. The wheel side suspension device 10RR is connected to the right rear side (right rear wheel position) of the sprung member HA, and the left rear wheel side suspension device 10RL is connected to the left rear side (left rear wheel position) of the sprung member HA. . Each suspension device has basically the same structure. Further, the right front wheel side suspension device 10FR is connected to the right front wheel WFR via the unsprung member LA, the left front wheel side suspension device 10FL is connected to the left front wheel WFL via the unsprung member LA, and the right rear wheel side suspension device 10RR is unsprung. The right rear wheel WRR is connected to the right rear wheel WRR via the member LA, and the left rear wheel side suspension device 10RL is connected to the left rear wheel WRL via the unsprung member LA. When the suspension devices 10FR, 10FL, 10RR, 10RL and the wheels WFR, WFL, WRR, WRL are collectively referred to, they may be simply referred to as the suspension device 10 and the wheels W.

  FIG. 2 is a schematic view showing the structure of the suspension device 10. The suspension device 10 includes a spring 11 and a damper (shock absorber) 12. The damper 12 includes a cylinder 121, a piston 122, and a piston rod 123. The cylinder 121 is a cylindrical member in which a viscous fluid (for example, oil) is sealed, and is connected to an unsprung member LA (specifically, a lower arm) at a lower end thereof. The piston 122 is disposed in the cylinder 121. The piston 122 divides the inside of the cylinder 121 into an upper chamber R1 and a lower chamber R2. The piston 122 can move in the cylinder 121 in the axial direction. The piston rod 123 is connected to the piston 122 at its lower end and is connected to the sprung member HA at its upper end. The piston 122 is formed with a communication passage 124 that communicates the upper chamber R1 and the lower chamber R2.

  In the damper 12 configured as described above, when the sprung member HA is relatively displaced with respect to the road surface due to the wheels W getting over the road surface unevenness, the piston 122 connected to the sprung member HA side is moved by the unsprung member LA. The inside of the cylinder 121 connected to the side (road surface side) is relatively displaced. A viscous fluid flows through the communication passage 124 formed in the piston 122 with this relative displacement. The vibration of the sprung member HA is attenuated by the resistance generated when the viscous fluid flows in the communication path 124.

  The spring 11 is disposed so as to surround the cylinder 121, and is connected to a retainer attached to the outer periphery of the cylinder 121 at the lower end and connected to the sprung member HA at the upper end. The spring 11 generates an elastic force accompanying the relative displacement of the sprung member HA with respect to the road surface. The spring 11 is a metal coil spring in the present embodiment, but may be an air spring used in an air suspension device or the like.

  As shown in FIG. 2, a variable throttle mechanism (variable control means) 13 is attached to the suspension device 10. The variable throttle mechanism 13 has a valve 131 and a suspension actuator 132. The valve 131 is provided in the communication path 124 and rotates to change the size of the flow passage cross-sectional area of at least a part of the communication path 124, that is, the valve opening OP. The suspension actuator 132 can be configured by, for example, a stepping motor. FIG. 1 shows suspension actuators 132FR, 132FL, 132RR, 132RL attached to the respective suspension devices 10FR, 10FL, 10RR, 10RL. These suspension actuators are disposed above the dampers 12 of the suspension devices 10FR, 10FL, 10RR, and 10RL, and are fixed to the sprung member HA. The suspension actuator 132 is connected to the valve 131 by a control rod or the like disposed inside the piston rod 123, for example. Therefore, when the suspension actuator 132 is operated, the valve 131 is rotated accordingly, and the valve opening degree OP is changed. The flow passage cross-sectional area of the communication passage 124 is changed by changing the valve opening OP. As a result, the magnitude of the resistance force generated when the viscous fluid flows in the communication path 124 is changed. Thereby, the damping force characteristic (damping coefficient) of the damper 12 is changed. Note that the damping force characteristic of the damper 12 is changed stepwise by a change in the rotation angle of the valve 131.

  Further, as shown in FIG. 1, the front wheel side active stabilizer 20F is between the right front wheel WFR and the left front wheel WFL, and the rear wheel side active stabilizer 20R is between the right rear wheel WRR and the left rear wheel WRL. Is provided. The front wheel side active stabilizer 20F is continuous from a pair of front wheel side torsion bars 21FR, 21FL extending coaxially along the left-right direction of the vehicle and from the front ends (vehicle outer ends) of the pair of front wheel side torsion bars 21FR, 21FL. A pair of front wheel side arms 22FR, 22FL and a front wheel side stabilizer actuator 23F connected to the base ends (vehicle inner ends) of the pair of torsion bars 21FR, 21FL. Similarly, the rear wheel side active stabilizer 20R includes a pair of rear wheel side torsion bars 21RR, 21RL that extend coaxially along the left-right direction of the vehicle, and the front ends of the pair of rear wheel side torsion bars 21RR, 21RL (vehicles). A rear wheel side stabilizer actuator 23R connected to a pair of rear wheel side arms 22RR, 22RL formed continuously from the outer end) and a base end (vehicle inner end) of the pair of rear wheel side torsion bars 21RR, 21RL. have.

  The pair of front wheel side torsion bars 21FR and 21FL is supported by a sprung member HA (specifically, a vehicle body) via a bracket 24F so as to be rotatable around an axis. Further, the front wheel side arms 22FR, 22FL extend from the front wheel side torsion bars 21FR, 21FL in a direction bent toward the vehicle front side. The tip of the front wheel side arm 22FR is connected to the unsprung member LA (for example, the lower arm) connected to the right front wheel WFR, and the tip of the front wheel side arm 22FL is connected to the unsprung member LA connected to the left front wheel WFL. Similarly, the pair of rear wheel side torsion bars 21RR, 21RL is supported by the sprung member HA so as to be rotatable around the axis via the bracket 24R. Further, the rear wheel side arms 22RR and 22RL extend from the rear wheel side torsion bars 21RR and 21RL in a direction bent toward the vehicle front side. The tip of the rear wheel side arm 22RR is connected to the unsprung member LA connected to the right rear wheel WRR, and the tip of the rear wheel side arm 22RL is connected to the unsprung member LA connected to the left rear wheel WRL.

  The front wheel side stabilizer actuator 23F rotates one of the pair of front wheel side torsion bars 21FR and 21FL relative to the other. The relative rotation angle is controlled by a stabilizer ECU 40 described later. Similarly, the rear wheel side stabilizer actuator 23R rotates one of the pair of rear wheel side torsion bars 21RR and 21RL relative to the other. The relative rotation is controlled by the stabilizer ECU 40. The stabilizer actuators 23F and 23R are constituted by, for example, an electric motor and a speed reducer.

As shown in FIG. 1, a suspension ECU 30 and a stabilizer ECU 40 are mounted on the vehicle. The stabilizer ECU 40 is configured mainly by a computer including a CPU, a ROM, a RAM, and the like, and based on detection values from various sensors (for example, a steering angle sensor, a vehicle speed sensor, and an acceleration sensor) (not shown), the front wheel side stabilizer actuator 23F. A signal indicating the front wheel actuator target rotation angle δ _f * which is the target rotation angle of the rear wheel actuator and a signal indicating the rear wheel actuator target rotation angle δ _r * which is the target rotation angle of the rear wheel side stabilizer actuator 23R. The front wheel side stabilizer actuator 23F operates based on the front wheel actuator target rotation angle δ _f *. By this operation, the relative rotation angle of the pair of front wheel side torsion bars 21FR and 21FL changes. The roll rigidity on the front wheel side of the sprung member HA is controlled by changing the relative rotation angle. The rear wheel side stabilizer actuator 23R operates based on the rear wheel actuator target rotation angle δ _r *. By this operation, the relative rotation angles of the pair of rear wheel side torsion bars 21RR and 21RL change. The roll rigidity on the rear wheel side of the sprung member HA is controlled by changing the relative rotation angle. The roll is suppressed by the roll rigidity control of the sprung member HA by the front wheel side active stabilizer 20F and the rear wheel side active stabilizer 20R.

A front wheel rotation angle sensor 56F is attached to the front wheel side stabilizer actuator 23F, and a rear wheel rotation angle sensor 56R is attached to the rear wheel side stabilizer actuator 23R. The front wheel rotation angle sensor 56F detects a front wheel actuator rotation angle δ _f that is the rotation angle of the front wheel side stabilizer actuator 23F. Rear wheel rotation-angle sensor 56R senses a wheel actuator rotation angle [delta] _r after a rotation angle of the rear wheel side stabilizer actuator 23R. The rotation angles δ _f and δ _r detected by both sensors are output to the stabilizer ECU 40 and the suspension ECU 30.

Further, the stabilizer ECU 40 calculates a front wheel side stabilizer generating force F _{stb_f} and a rear wheel side stabilizer generating force F _{stb_r} . The front wheel side stabilizer generating force F _{stb_f} is a force in the roll direction that is generated when the front wheel side active stabilizer 20F operates normally. The rear wheel side stabilizer generating force F _{stb_r} is a force in the roll direction that is generated when the rear wheel side active stabilizer 20R operates normally. These generated forces are forces that should be generated by the active stabilizer when the active stabilizer operates normally and the roll angle of the sprung member HA reaches the target roll angle, and are calculated based on, for example, the target anti-roll moment. The The target anti-roll moment can be calculated based on the target roll angle, lateral acceleration, front / rear roll stiffness distribution ratio, and the like.

Further, the stabilizer ECU 40 outputs a front wheel side operation state signal S _f and a rear wheel side operation state signal S _r to the suspension ECU 30. The front wheel side operation state signal S _f is a signal indicating whether the front wheel side active stabilizer 20F is operating normally or is abnormal, and the rear wheel side operation state signal S _r is the rear If the wheel side active stabilizer 20R is operating normally or is abnormal, it is a signal indicating what kind of abnormality it is. For example, when the operation state signals S _f and S _r are signals representing “0”, the active state of the active stabilizer is a normal state, and when the operation state signals are “1”, the active stabilizer is described later. If the active stabilizer is a signal indicating “2”, the active stabilizer is in an operation lock abnormal state to be described later, and if the signal is “3”, the active stabilizer is in other abnormality. State. Whether or not the active stabilizer is normal, or what kind of abnormality is abnormal, depends on the difference between the front wheel actuator rotation angle δ _f and the front wheel actuator target rotation angle δ _f * and the rear wheel actuator rotation angle δ. _This can be determined from the difference between _r and the rear wheel actuator target rotation angle δ _r *.

The suspension ECU 30 is also mainly composed of a computer having a CPU, a ROM, a RAM and the like. The suspension ECU 30 controls the damping force characteristics (damping coefficients) of the dampers 12 of the four suspension devices 10. Specifically, the right front wheel side required damping force _{Freq_fr} , which is the target value of the damping force that should be generated by the damper 12 of the right front wheel side suspension device 10FR, and the damping force target that should be generated by the damper 12 of the left front wheel side suspension device 10FL. left front wheel demanded damping force F _{Req_fl} a value, right rear wheel suspension system which is a target value of the damping force damper 12 to be generated by the 10RR right rear wheel required damping force F _{Req_rr,} left rear wheel suspension system 10RL The left rear wheel side required damping force F _{req_rl} , which is the target value of the damping force that should be generated by the damper 12, is calculated, and the suspension actuator corresponding to the calculated signal indicating each required damping force (required damping force for each wheel). It outputs to 132FR, 132FL, 132RR, 132RL. The suspension ECU 30 corresponds to the damping force control device of the present invention.

As shown in FIG. 2, a sprung acceleration sensor 51, a road surface vertical acceleration sensor 52, and a stroke sensor 53 are attached in the vicinity of each suspension device. The sprung acceleration sensor 51 is attached to each wheel position (right front wheel position, left front wheel position, right rear wheel position, left rear wheel position) of the sprung member HA, and the sprung member HA in the vertical direction at that position. Right front wheel side sprung acceleration x _{b_fr} ", left front wheel side sprung acceleration x _{b_fl} ", right rear wheel side sprung acceleration x _{b_rr} ", left rear wheel side sprung acceleration x _{b_rl} " To do. The road surface vertical acceleration sensor 52 is attached to each unsprung member LA connected to each wheel W, and is connected to each unsprung member LA by measuring the acceleration along the vertical direction of each unsprung member LA. Right front wheel side road acceleration x _{r_fr} ", left front wheel side road acceleration x _{r_fl} ", right rear wheel side road acceleration x _{r_rr} ", left rear wheel side road acceleration x _{r_rl} "Is detected respectively. The stroke sensor 53 is attached to each suspension device. By measuring the stroke displacement amount of the damper 12 of the suspension device 10, that is, the relative displacement amount of the piston 122 with respect to the cylinder 121, the road surface at the right front wheel position of the sprung member HA. Right front wheel side spring top-road relative displacement amount x _{s_fr} (= x _{r_fr} -x _{b_fr} ), the amount of displacement along the vertical direction of the sprung member HA with respect to the left front wheel side spring at the left front wheel position of the sprung member HA Upper-road relative displacement x _{s_fl} (= x _{r_fl} -x _{b_fl} ), right rear wheel side spring upper-road relative displacement x _{s_rr} (= x _{r_rr} -x _{b_rr} ) at the position of the right rear wheel of the sprung member HA , The left rear wheel side sprung-road relative displacement amount x _{s_rl} (= x _{r_rl} -x _{b_rl} ) at the position of the left rear wheel of the sprung member HA is detected.

As shown in FIG. 1, a roll angular acceleration sensor 54 and a pitch angular acceleration sensor 55 are attached to the sprung member HA. The roll angular acceleration sensor 54 detects an angular acceleration (roll angular acceleration) θ _R ″ of the roll angle θ _R representing the angular displacement of the sprung member HA in the roll direction (around the longitudinal axis). The pitch angular acceleration sensor 55 is a spring. The angular acceleration (pitch angular acceleration) θ _P ″ of the pitch angle θ _P representing the angular displacement of the upper member HA in the pitch direction (the direction around the left and right axes) is detected.

  FIG. 3 is a diagram schematically showing an input / output configuration of the suspension ECU 30. On the input side of the suspension ECU 30, a sprung acceleration sensor 51, a road surface vertical acceleration sensor 52, a stroke sensor 53, a roll angular acceleration sensor 54, a pitch angular acceleration sensor 55, a front wheel rotation angle sensor 56F, a rear wheel rotation angle sensor 56R, and a stabilizer. The ECU 40 is connected.

The sprung acceleration sensor 51 calculates the right front wheel side sprung acceleration x _{b_fr} ", the left front wheel side sprung acceleration x _{b_fl} ", the right rear wheel side sprung acceleration x _{b_rr} ", and the left rear wheel side sprung acceleration x _{b_rl} " The vertical acceleration sensor 52 represents the right front wheel side road surface acceleration x _{r_fr} ", the left front wheel side road surface acceleration x _{r_fl} ", the right rear wheel side road surface acceleration x _{r_rr} ", the left rear wheel side road surface acceleration x _{r_rl} ", and the stroke sensor 53 represents the right front wheel. Side spring-to-road relative displacement x _{s_fr} (= x _{r_fr} -x _{b_fr} ), Left front wheel side spring-to-road relative displacement x _{s_fl} (= x _{r_fl} -x _{b_fl} ), Right rear wheel-side spring on road surface Relative displacement x _{s_rr} (= x _{r_rr} -x _{b_rr} ) and left rear wheel side sprung-road relative displacement x _{s_rl} (= x _{r_rl} -x _{b_rl} ) are output to the suspension ECU 30, respectively. The roll angular acceleration sensor 54 outputs the roll angular acceleration θ _R ″ and the pitch angular acceleration sensor 55 outputs the pitch angular acceleration θ _P ″ to the suspension ECU 30. The front wheel rotation angle sensor 56F outputs the front wheel actuator rotation angle δ _f to the suspension ECU 30 and the rear wheel rotation angle sensor 56R outputs the rear wheel actuator rotation angle δ _r to the suspension ECU 30, respectively. The stabilizer ECU 40 _outputs the front wheel side stabilizer generating force F _{stb_f} , the rear wheel side stabilizer generating force F _{stb_r} , the front wheel side operating state signal S _f and the rear wheel side operating state signal S _r to the suspension ECU 30.

The suspension actuators 132FR, 132FL, 132RR, 132RL are electrically connected to the output side of the suspension ECU 30 via a drive circuit (not shown). A signal representing the right front wheel side required damping force F _{req_fr} from the suspension ECU 30 represents the suspension actuator 132FR, and a signal representing the left front wheel side required damping force F _{req_fl} represents the suspension actuator 132FL and the right rear wheel side required damping force F _{req_rr} . A signal is output to the suspension actuator 132RR, and a signal indicating the left rear wheel side required damping force _{Freq_rl} is output to the suspension actuator 132RL.

FIG. 4 is a diagram showing the internal configuration of the suspension ECU 30 for each functional block. As shown in the figure, the suspension ECU 30 includes a mode required damping force calculation unit 31 and each wheel required damping force calculation unit 32 therein. The mode required damping force calculation unit 31 calculates a heave required damping force F _{req_H} , a roll required damping force F _{req_R} and a pitch required damping force F _{req_P} that suppress vibrations of the sprung member HA, and calculates these required damping forces. Output. The heave required damping force F _{req — H} is a control target value of a damping force (heave damping force) acting in the vertical direction of the center of gravity position of the sprung member HA. The requested roll damping force F _{req_R} is a control target value of the damping force (roll damping force) acting in the roll direction at the center of gravity of the sprung member HA. The required pitch damping force F _{req_P} is a control target value of the damping force (pitch damping force) acting in the pitch direction at the center of gravity of the sprung member HA.

Each wheel requested damping force calculation unit 32 _{inputs the} heave requested damping force F _{req_H} , the roll requested damping force F _{req_R} and the pitch requested damping force F _{req_P} , and each wheel requested damping force (right) based on these requested damping forces. Front wheel side required damping force F _{req_fr} , left front wheel side required damping force F _{req_fl} , right rear wheel side required damping force F _{req_rr} and left rear wheel side required damping force F _{req_rl} ) A signal is output to each corresponding suspension actuator 132FR, 132FL, 132RR, 132RL.

  In the above configuration, when any one of the sprung accelerations at the respective wheel positions obtained from the detection value of the sprung acceleration sensor 51 exceeds a predetermined threshold, the mode required damping force calculation unit 31 of the suspension ECU 30 performs the mode required damping force. Each wheel required damping force calculation unit 32 executes a process for calculating each wheel required damping force (each wheel required damping force calculating process). .

FIG. 5 is a flowchart showing the flow of the mode required damping force calculation process. The mode required damping force calculation unit 31 starts this processing at step (hereinafter, step number is abbreviated as S) 100 in FIG. Next, in S102, detection values are input from the sprung acceleration sensor 51, the road surface vertical acceleration sensor 52, the stroke sensor 53, the roll angular acceleration sensor 54, and the pitch angular acceleration sensor 55. Next, in S104, the input detection value is calculated (for example, differentiation or integration), whereby the vertical speed (sprung speed) _{xb_fr} ', _{xb_fl} ', _{xb_rr} 'of the sprung member HA at each wheel position. , X _{b_rl} ′, vertical displacement of the sprung member HA at each wheel position (sprung displacement) x _{b_fr} , x _{b_fl} , x _{b_rr} , x _{b_rl} , vertical speed of the road surface at each wheel position (road vertical speed) x _{r_fr} ', X _{r_fl} ', x _{r_rr} ', x _{r_rl} ', the vertical displacement of the road surface at each wheel position (road vertical displacement) x _{r_fr} , x _{r_fl} , x _{r_rr} , x _{r_rl} , the spring against the road vertical speed at each wheel position Up speed (relative speed between sprung and road surface) x _{s_fr} '(= x _{r_fr} ' -x _{b_fr} '), x _{s_fl} ' (= x _{r_fl} '-x _{b_fl} '), x _{s_rr} '(= x _{r_rr} ' -x _{b_rr} '), X _{s_rl} ' (= x _{r_rl} '-x _{b_rl} '), vertical displacement (heave displacement) x _H of the center of gravity position of sprung member HA, roll angle θ _R , pitch angle θ _P , heave speed x _H ', Roll angular velocity θ Calculate the amount required for calculation, such as _R ′, pitch angular velocity θ _P ′, and heave acceleration x _H ″. Heave displacement x _H , heave velocity x _H ′, and heave acceleration x _H ″ are calculated at each wheel position. It can be calculated from the sprung acceleration.

上記式(eq.1)中のM_bはバネ上部材ＨＡ（車体）の質量、x_H"はバネ上部材ＨＡの重心位置の上下加速度（ヒーブ加速度）である。また、上記式(eq.2)中のI_Rはロール慣性モーメント、θ_R"はロール角加速度、T_fは前輪側のトレッド、T_rは後輪側のトレッドである。また、上記式(eq.3)中のI_Pはピッチ慣性モーメント、θ_P"はピッチ角加速度、Lはホイールベースである。計算を簡素化するため、T_f，T_r，Lは「２」に設定することができる。 Next, in S106, a heave demand damping coefficient _{Creq_H} , a roll demand damping coefficient _{Creq_R} , and a pitch demand damping coefficient _{Creq_P} are calculated by applying the non-linear _H∞ control theory. In this calculation, the four-wheel model of the vehicle shown in FIG. 7 is used as a dynamic motion model. As can be seen from the figure, this four-wheel model is a model that does not consider the front wheel side stabilizer generating force F _{stb_f} generated by the front wheel side active stabilizer 20F and the rear wheel side stabilizer generating force F _{stb_r} generated by the rear wheel side active stabilizer 20R. . The heave (up / down) motion equation, roll motion equation, and pitch motion equation at the center of gravity of the sprung member HA derived from the four-wheel model are expressed as, for example, the following equations (eq.1) to (eq.3). Is done.

In the above equation (eq.1), M _b is the mass of the sprung member HA (vehicle body), and x _H ″ is the vertical acceleration (heave acceleration) of the center of gravity position of the sprung member HA. Also, the above equation (eq. In FIG. 2, I _R is the roll inertia moment, θ _R ″ is the roll angular acceleration, T _f is the tread on the front wheel side, and T _r is the tread on the rear wheel side. In the above equation (eq.3), I _P is the pitch moment of inertia, θ _P ″ is the pitch angular acceleration, and L is the wheelbase. To simplify the calculation, T _f , T _r , and L are “2”. Can be set.

上記式(eq.4)中のF_fr，F_fl，F_rr，F_rlは各サスペンション装置１０のダンパ１２が発生する減衰力、K_fr，K_fl，K_rr，K_rlは各サスペンション装置１０のバネ１１のバネ定数である。 Further, the equation (eq.1) ~ (eq.3) in _{f fr, f fl, f rr} , f rl is the suspension device 10FR, vertical 10FL, 10RR, each wheel position of the sprung member HA by 10RL Vertical force acting in the direction. These vertical forces are the resultant force of the spring 11 and the damper 12 and are represented by the following equation (eq.4).

In the above equation (eq.4), F _fr , F _fl , F _rr , F _rl are damping forces generated by the dampers 12 of the suspension devices 10, and K _fr , K _fl , K _rr , K _rl are the suspension devices 10. This is the spring constant of the spring 11.

Further, the damping force acting in the vertical direction at the center of gravity of the sprung member HA is the heave damping force F _H , the damping force acting in the roll direction is the roll damping force F _R , and the damping force acting in the pitch direction is the pitch damping force. When F _P, these damping force (the mode damping force), the damping force of each damper relationship representing the balance of forces between the (each wheel damping force), the following equation (eq.5) ~ (eq.7) It is expressed as

The heave damping force F _H is the product C _H · x _H 'of the heave damping coefficient C _H and the heave displacement velocity x _H ', and the roll damping force F _R is the product C _R · of the roll damping coefficient C _R and the roll angular velocity θ _R '. The pitch damping force _FP is expressed by θ _R ′ by the product C _P · θ _P ′ of the pitch damping coefficient C _P and the pitch angular velocity θ _P ′. Therefore, the above formulas (eq.1) to (eq.3) can be expressed as the following formulas (eq.8) to (eq.10), for example.

_Further , the relationship between the sprung displacement amounts x _{b_fr} , x _{b_fl} , x _{b_rr} , x _{b_rl at} each wheel position and the heave displacement amount x _H , the roll angle θ _R , and the pitch angle θ _P can be calculated using a mode conversion matrix, for example. It can be expressed as the following formula (eq.11).

The state space expression of the four-wheel model is expressed as the following equation (eq.12) by the above equation of motion and relational expression.

また、上記式(eq.12)中のA_p，B_p1，B_p12(x_p)，C_p1，D_p12(x_p)は係数行列であり、上記式(eq.12)が成り立つように定められる。 In the above equation (eq.12), the state quantity x _p , the disturbance w, the control input u, and the evaluation output z _p are given by, for example, the following equation (eq.13).

In addition, A _p , B _p1 , B _p12 (x _p ), C _p1 , D _p12 (x _p ) in the above equation (eq.12) are coefficient matrices, so that the above equation (eq.12) holds. Determined.

Based on the equation (eq.12), the generalized plant shown in FIG. 8 is designed. A frequency weight W _s (s) acts on the evaluation output z _p represented in the generalized plant, and a frequency weight W _u (s) acts on the control input u. The state space representation of the generalized plant is the state space representation of the four-wheel model shown in the above equation (eq.12), the state space representation of the frequency weight W _s (s) shown in the following equation (eq.14), and Using the state space representation of the frequency weight W _u (s) shown in the equation (eq.15), it is expressed as the following equation (eq.16).

Equation (eq.16) is a bilinear system. Therefore, if positive definite symmetric matrix P satisfying the Riccati inequalities represented by the following formula (eq.17) is present, generalized plant was internally stable and L ₂ gains a positive constant γ control law u to below = k (x) can be obtained.

このようにして、非線形Ｈ_∞制御理論を適用して算出された制御則から制御入力uが求められる。そして、制御入力uから、ヒーブ減衰係数C_Hの制御目標値であるヒーブ要求減衰係数C_{req_H}、ロール減衰係数C_Rの制御目標値であるロール要求減衰係数C_{req_R}、ピッチ減衰係数C_Pの制御目標値であるピッチ要求減衰係数C_{req_P}が得られる。 At this time, the control law u = k (x) is given by, for example, the following equation (eq.18).

In this way, the control input u is obtained from the control law calculated by applying the non-linear _H∞ control theory. Then, the control input u, a control target value of the heave damping coefficient C _H heave required damping coefficient C _{req_h,} roll damping coefficient C roll required damping coefficient is controlled target value of _R C _{req_r,} control of the pitch damping coefficient C _P A required pitch attenuation coefficient C _{req_P} which is a target value is obtained.

The mode required damping force calculation unit 31 _{obtains the} heave required damping coefficient C _{req_H} , the roll required damping coefficient C _{req_R} and the pitch required damping coefficient C _{req_P} as described above in S106, and then proceeds to S108, where heave required damping force F _{Calculate req_H} , roll requested damping force _{Freq_R} , and pitch requested damping force _{Freq_P} . The heave demand damping force F _{req_H} is calculated by multiplying the heave demand damping coefficient C _{req_H} by the heave speed x _H ′. The roll required damping force F _{req_R} is calculated by multiplying the roll required damping coefficient C _{req_R} by the roll angular velocity θ _R ′. The pitch required damping force F _{req_P} is calculated by multiplying the pitch required damping coefficient C _{req_P} by the pitch angular velocity θ _P ′. When these required damping forces act on the sprung member HA, vibration in each mode direction (heave direction, roll direction, pitch direction) of the sprung member HA is suppressed. Next, the mode required damping force calculation unit 31 proceeds to S110, and _outputs a heave required damping force _{Freq_H} , a roll required damping force _{Freq_R} , and a pitch required damping force _{Freq_P} . Thereafter, the process proceeds to S112 and this process is terminated.

6A to 6D are flowcharts showing the flow of the required damping force calculation processing for each wheel. Each wheel required damping force calculation unit 32 starts this processing in S200 of FIG. 6A. Next, in S202, heave requested damping force _{Freq_H} , roll requested damping force _{Freq_R,} and pitch requested damping force _{Freq_P} are input. Subsequently, in S204, the front wheel actuator rotation angle [delta] _f from the front wheel rotation angle sensor 56F, inputs the rear wheel actuator rotation angle [delta] _r from the rear wheel rotational angle sensor 56R. Next, in S206, the front wheel side stabilizer generating force F _{stb_f} and the rear wheel side stabilizer generating force F _{stb_r} obtained by calculation from the stabilizer ECU 40 are input.

Next, each wheel required damping force calculation unit 32 performs an abnormality diagnosis of the active stabilizers (front wheel side active stabilizer 20F and rear wheel side active stabilizer 20R) in S208. According to this abnormality diagnosis, whether the operating state of the front wheel side active stabilizer 20F and the rear wheel side active stabilizer 20R is normal or abnormal, and if abnormal, the abnormality is any of preset abnormality A to abnormality J Is diagnosed. This abnormality diagnosis is made based on the front wheel side operation state signal S _f and the rear wheel side operation state signal S _r . For example, according to the above-described example, when the operating state signal is “0”, the active stabilizer is operating normally, when it is “1”, it is an operation-free abnormality, and when it is “2”, the operation is locked. If it is abnormal and “3”, it is assumed that there is another abnormality. Then, in S208, based on the front wheel side working state signal S _f and the rear-wheel-side operating condition signal S _r, either a is one of the diagnosis results of eleven the operating state of the active stabilizer is shown in Figure 9 is made as The

As shown in FIG. 9, when both the front wheel side operation state signal S _f and the rear wheel side operation state signal S _r are “0”, it is diagnosed that the operation state of the active stabilizer is “normal”. When S _f is “0” and S _r is “1”, “abnormal A” is diagnosed, and when S _f is “0” and S _r is “2”, “abnormal B” is diagnosed. The Further, when S _f is “1” and S _r is “0”, “abnormal C”, when both S _f and S _r are “1”, “abnormal D” and S _f are “1”. When _Sr is “2”, “abnormal E” is diagnosed. Further, when S _f is “2” and S _r is “0”, “abnormal F”, and when S _f is “2” and S _r is “1”, “abnormal G”, S _f and When both S _r are “2”, “abnormal H” is diagnosed. Furthermore, when S _f is "3" is diagnosed as "abnormal I" Whatever signal S _r, when S _r is "3" was in any signal S _f However, “abnormal J” is diagnosed.

After diagnosing the operation state of the active stabilizer as described above, each wheel required damping force calculation unit 32, in S210, each wheel required damping force (right front wheel side required damping force _{Freq_fr} , left front wheel side required damping force). F _{req_fl} , right rear wheel side required damping force F _{req — rr} , left rear wheel side required damping force F _{req — rl} ) are set as reference expressions used for calculating H, P, R, W. These reference formulas are shown in the following formulas (eq.19) to (eq.22).

Equation (eq.19) is an equation representing the balance of forces between the heave demand damping force F _{req_H} and each wheel demand damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , F _{req_rl} (heave-each wheel demand Damping force relational expression). As can be seen from this equation, the heave required damping force F _{req_H} is represented by the sum F _{req_fr} + F _{req_fl} + F _{req_rr} + F _{req_rl} of each wheel required damping force. The expression P shown in the equation (eq.20) is a relational expression (pitch-required for each wheel) _indicating the balance of force between the required pitch damping force F _{req_P} and each wheel required damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , F _{req_rl.} Damping force relational expression). As can be seen from this equation, is represented by the difference between the sum _F req_fr + F req_fl pitch required damping force F _{Req_P} the sum of required damping force of the rear wheel side _F req_rr + F req_rl and the front-wheel-side demanded damping force .

In addition, the R equation shown in the equation (eq.21) includes a roll requested damping force F _{req_R} , each wheel requested damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , F _{req_rl} , front wheel side stabilizer generating force F _{stb_f} , It is a relational expression (roll-each wheel demand damping force relational expression) showing balance of power with rear wheel side stabilizer generating force _{Fstb_r} . R expression is a force obtained by subtracting the front wheel side stabilizer generated force F _{Stb_f} and the rear-wheel-side stabilizer generated force F _{Stb_r} from the roll required damping force F _{req_r,} the sum of the demanded damping force of the left wheel side _F req_fl + F req_rl and right wheel _Represents the balance of force with the roll damping force by each damper represented by the difference from the sum of the required damping forces of F _req — _fr + F _{req — rr} . By using this R equation for calculation of each wheel required damping force, a force obtained by subtracting the stabilizer generating force from the roll required damping force F _{req_R} derived without considering the stabilizer generating force is distributed to each wheel required damping force. . In this way, by incorporating the stabilizer generating force into the R-type, the stabilizer generating force and the damping force by each damper are adjusted.

In addition, the W expression shown in the expression (eq.22) is an expression obtained by a constraint condition that the sprung member HA is not twisted (the torsional force is 0). The left side of the equation (eq.22) is the front wheel side of the sprung member HA represented by the difference between the left front wheel side required damping force _{Freq_fl} and the right front wheel side required damping force _{Freq_fr} and the front wheel side stabilizer generating force _{Fstb_f.} The force acting in the roll direction. The right side of the equation (eq.22) represents the sprung member HA represented by the difference between the left rear wheel side required damping force _{Freq_rl} and the right rear wheel side required damping force _{Freq_rr} and the rear wheel side stabilizer generating force _{Fstb_r.} This is the force acting in the roll direction on the rear wheel side. Based on the constraint condition that no twisting occurs, the force acting in the roll direction on the front wheel side of the sprung member HA is equal to the force acting in the roll direction on the rear wheel side. Therefore, Formula (eq.22) is materialized. This W formula corresponds to the constraint condition formula of the present invention.

  Stabilizer generating force is also incorporated in the W type. That is, the relationship between the stabilizer generating force and the damping force by each damper is expressed based on the condition that the sprung member HA is not twisted. By determining the required damping force for each wheel based on this relationship, the damping force of each damper is controlled in consideration of the stabilizer generating force under the condition that the torsion of the sprung member HA does not occur.

In principle, values input from the stabilizer ECU 40 are applied to the front wheel side stabilizer generating force F _{stb_f} and the rear wheel side stabilizer generating force F _{stb_r} included in the R type and the W type. The stabilizer ECU 40 calculates a front wheel side stabilizer generating force F _{stb_f} and a rear wheel side stabilizer generating force F _{stb_r} that are generated when the front wheel side active stabilizer 20F and the rear wheel side active stabilizer 20R are operating normally. Therefore, when both active stabilizers are operating normally, it is possible to calculate an appropriate required damping force for each wheel in consideration of the stabilizer generating force using these equations.

  Note that the setting process of S210 is provided to facilitate the understanding of the invention. In practice, these H-type, P-type, R-type, and W-type need only be stored in the suspension ECU 30, It is not necessary to set each of these formulas in the flow of each wheel required damping force calculation process.

Next, each wheel required damping force calculation unit 32 determines in S212 whether or not both active stabilizers 20F and 20R are operating normally. This determination is performed based on whether or not the operating state of the active stabilizer is diagnosed as “normal” in S208. When both the active stabilizers 20F and 20R are normal (S212: Yes), the process proceeds to S214, and the expressions H, P, R, and W shown in equations (eq.19) to (eq.22) are performed. Using each wheel, the required damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , and F _{req_rl} are calculated.

  After calculating each wheel required damping force using the H formula, P formula, R formula, and W formula in S214, each wheel required damping force calculation unit 32 proceeds to S216 and represents the calculated each wheel required damping force. A signal is output to each corresponding suspension actuator 132. Each suspension actuator 132 operates based on the input signal. The rotation of each corresponding valve 131 is controlled by the operation of the suspension actuator 132. By controlling the operation of the variable throttle mechanism 13 as described above, the damping force characteristics of each damper are controlled so that the damping force of each damper becomes the required wheel damping force obtained in S214.

Thus, when both the active stabilizers 20F and 20R are operating normally, relational expressions and conditions in which the front wheel side stabilizer generating force F _{stb_f} and the rear wheel side stabilizer generating force F _{stb_r} input from the stabilizer ECU 40 are taken into consideration. The required damping force for each wheel is calculated using the formula. Thereby, each wheel required damping force in consideration of the stabilizer generating force is obtained. By controlling the damping force characteristics of each damper on the basis of the required wheel damping force thus obtained, the stabilizer generating force by the active stabilizer and the damping force of each damper are controlled in a coordinated manner. Further, interference between roll stiffness control by the active stabilizer and damping force characteristic control of each damper is prevented, and deterioration of damping force characteristic control performance due to control interference is suppressed.

If the determination result in S212 is No, that is, if the active stabilizer operation state is not diagnosed as “normal”, each wheel required damping force calculation unit 32 proceeds to S220 in FIG. 6B. In S220, it is determined whether or not the operating state of the active stabilizer has been diagnosed as “abnormal A”. When “abnormality A” is diagnosed, the front wheel side operation state signal S _f is 0 and the rear wheel side operation state signal S _r is 1, that is, the front wheel side active stabilizer 20F is normal, and the rear wheel side This is a case where the active stabilizer 20R is in an operation free abnormality. An operation-free abnormality is an abnormality in which the active stabilizer runs idle. Specifically, this is an abnormality in which the torsion bar constituting the active stabilizer idles with respect to the actuator. In the case of an operation-free abnormality, the active stabilizer cannot exhibit a stabilizer generating force by itself, and cannot exhibit a restoring force against the twist even if it is twisted by an external input. That is, the stabilizer generating force is zero.

In the case of “abnormality A”, the rear wheel side active stabilizer 20R is in an operation free abnormality, and _{therefore the} rear wheel side stabilizer generating force F _{stb_r} is actually zero. However, since the stabilizer ECU 40 calculates some rear wheel side stabilizer generating force F _{stb_r} that opposes the roll moment under the assumption that the rear wheel side active stabilizer 20R is normal, it is actually generated. The rear wheel side stabilizer generating force (= 0) being generated is different from the rear wheel side stabilizer generating force obtained by calculation. Therefore, in calculating each wheel required damping force using the four reference equations set in S208, unless the rear wheel side stabilizer generating force F _{stb_r} included in the R equation and the W equation is set to 0, The appropriate damping force required for each wheel cannot be calculated. If light of these things, the operating state of the active stabilizer is "abnormal A" (S220: Yes), the process proceeds to S222, R-type and W type to indicate R _a formula and the following formula formula (eq.23) correcting the W _a formula shown in (eq.24).

As can be seen from equation (eq.23) and formula (eq.24), R _a formula were corrected to 0-wheel-side stabilizer generated force F _{Stb_r} after in R formula wherein, W _a formula after in W-type This is a formula in which the wheel side stabilizer generating force F _{stb_r} is corrected to zero. The correction process performed in S222 corresponds to the correction means of the present invention. After correcting the R formula to the R _a formula and the W formula to the W _a formula at S222, each wheel required damping force calculation unit 32 proceeds to S224, and the H formula, P formula, R _a formula, and W _a formula are changed. Using each wheel, the required damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , and F _{req_rl} are calculated. Thereafter, the process proceeds to S216.

If the determination result in S220 is No, that is, if the active stabilizer operating state is not “abnormal A”, each wheel required damping force calculation unit 32 proceeds to S226. In S226, it is determined whether or not the operating state of the active stabilizer is diagnosed as “abnormal B”. When “abnormal B” is diagnosed, when the front wheel side operation state signal S _f is 0 and the rear wheel side operation state signal S _r is 2, that is, the front wheel side active stabilizer 20F is normal, the rear wheel side This is a case where the active stabilizer 20R has an operation lock abnormality. The operation lock abnormality is an abnormality in which the stabilizer actuator is locked (fixed) to a certain rotation angle for some reason and cannot be operated to have any other rotation angle.

  FIG. 10 is a schematic diagram of the active stabilizer 20 in which an operation lock abnormality has occurred. As shown in the figure, since the pair of torsion bars 21R and 21L are locked in a state where they are rotated by a certain rotation angle within the stabilizer actuator 23, the arm 22R connected to one torsion bar 21R and the other torsion bar The arm 22L connected to the bar 21L is fixed in a state of relative rotation around the axes of the torsion bars 21R and 21L. Therefore, the active stabilizer 20 is locked in a twisted state. That is, the twisted state shown in FIG. 10 becomes the reference state (neutral state).

FIG. 11 is a schematic view of the active stabilizer 20 of FIG. 10 as viewed from the direction of the arrow in the figure. In FIG. 11, one arm 22R and the other arm 22L indicated by solid lines represent the rotational positions of the arms in the reference state shown in FIG. The angle (relative rotation angle) φ _L formed by both arms 22R and 22L indicated by the solid line is the relative rotation angle of the pair of torsion bars 21R and 21L when the stabilizer actuator 23 is locked, that is, the lock angle of the active stabilizer 20. Represents. In this embodiment, the lock angle φ _L can be calculated based on the front wheel actuator rotation angle δ _f or the rear wheel actuator rotation angle δ _r .

When the active stabilizer 20 that is abnormal in operation lock is twisted by the external input (for example, road surface input or centrifugal force) from the reference state shown in FIG. 10, both the arms 22R and 22L rotate, for example, as indicated by the solid line in FIG. The position is displaced from the position to the rotational position indicated by the broken line. Accordingly, a restoring force against torsion is generated. That is, the active stabilizer 20 functions as a conventional stabilizer when the operation lock is abnormal, and generates a restoring force when twisted from the reference state by an external input. The restoring force generated when it is actuated lock abnormality referred to herein as abnormal occurrence force F _C.

The abnormal-time generated force F _C is generated when the active stabilizer 20 that is abnormal in operation lock is further twisted from the reference state by an external input. Since the abnormality generated force F _C changes in proportion to the amount of twist from the reference state, it can be calculated based on the amount of twist. Also, if the active stabilizer 20 is further twisted from the reference state shown in FIG. 10, the rotation angle of the active stabilizer (a pair of torsion bars 21R, the relative rotation angle of 21L) is not changed from the lock angle phi _L pair The relative rotation angles of the arms 22R and 22L change in proportion to the amount of twist. That twist from the reference state is a pair of arms 22R, represented by the difference between 22L of relative rotation angle phi _a and the locking angle phi _L. Therefore abnormal occurrence force F _C may be calculated based on the difference between the relative rotational angle phi _a and the locking angle phi _L. For example, as shown in FIG. 11, when the active stabilizer 20 in the operation-locked state is twisted by an external input and both arms 22R and 22L are rotationally displaced to the rotational positions indicated by the broken lines, both arms 22R and 22L after displacement are displaced. An abnormality generated force F _C (= K _s (φ _a −φ) having a magnitude obtained by multiplying the difference (φ _a −φ _L ) between the relative rotation angle φ _a and the lock angle φ _L by the spring constant K _s of the active stabilizer 20. _L )) occurs.

For this reason, the front wheel abnormality active force F _{C_f} generated when the front wheel side active stabilizer 20F is in an operation lock abnormality is obtained by the following equation (eq.25), and the rear wheel side active stabilizer 20R is in an operation lock abnormality. The rear wheel abnormality occurrence force F _{C_r that} is _sometimes generated is expressed by the following equation (eq.26).

In the above equation (eq.25), K _{s_f} is the spring constant of the front wheel side active stabilizer 20F, φ _fa is the relative rotation angle (front wheel arm relative rotation angle) of the arms 22FR and 22RL of the front wheel side active stabilizer 20F where the operation lock is abnormal. , Φ _fL is a lock angle (front wheel lock angle) of the front wheel side active stabilizer 20F that is abnormal in operation lock. φ _fL is also the relative rotation angle of the arms 22FR and 22FL in the reference state of the front wheel side active stabilizer 20F, which is an operation lock abnormality. In the above equation (eq.26), K _{s_r} is the spring constant of the rear wheel side active stabilizer 20R, φ _ra is the relative rotation angle (rear wheel) of the arms 22RR and 22RL of the rear wheel side active stabilizer 20R that is abnormal in operation lock. (Arm relative rotation angle), φ _rL is the lock angle (rear wheel lock angle) of the rear wheel side active stabilizer 20R that is abnormal in operation lock. φ _rL is also the relative rotation angle of the arms 22RR and 22RL in the reference state of the rear wheel side active stabilizer 20R, which is an operation lock abnormality.

The relative rotation angle of the pair of arms is represented by the roll (tilt) of the sprung member HA. This roll is represented by the difference between the sprung-road relative displacement amount at the right wheel position of the sprung member HA and the sprung-road relative displacement amount at the left wheel position of the sprung member HA. Therefore, the front wheel arm relative rotation angle φ _fa in the above equation (eq.25) is the difference between the right front wheel side sprung-road relative displacement amount x _{s_fr} and the left front wheel side sprung-road relative displacement amount x _{s_fl.} Based on the above equation (eq.26), the rear wheel arm relative rotation angle φ _ra is the right rear wheel spring-on-road relative displacement amount x _{s_rr} and the left rear wheel-side spring-on-road relative displacement amount x _{s_rl} Can be estimated based on the difference.

When the operation state of the active stabilizer is “abnormal B”, the rear wheel side active stabilizer 20R has an operation lock abnormality, and _{therefore the} rear wheel side active stabilizer 20R generates a rear wheel abnormality generation force F C — _r . However, since the stabilizer ECU 40 calculates the rear wheel side stabilizer generating force F _{stb_r} that opposes the roll moment on the assumption that the rear wheel side active stabilizer 20R is normal, the rear wheel side that is actually generated is calculated. The stabilizer generating force (= F _{C_r} ) and the rear wheel side stabilizer generating force obtained by calculation are different. Accordingly, in calculating the required damping force for each wheel using the four reference equations set in S208, the rear wheel side stabilizer generating force F _{stb_r} included in the R equation and the W equation is set to a value calculated by the stabilizer ECU 40. Instead, if the rear wheel abnormality generated force F C — _r is not changed, it is impossible to correctly calculate the required damping force for each wheel in consideration of the stabilizer generated force using these equations. Based on these facts, when the operation state of the active stabilizer is “abnormal B” (226: Yes), each wheel required damping force calculation unit 32 first proceeds to S228, and the rear wheel according to the above equation (eq.26). Calculate the abnormal force F _{C_r} . The calculation processing of the generated force at the rear wheel abnormality performed in S228 corresponds to the abnormal force generated force calculation means of the present invention. Next, in S230, the R and W formulas are shown in the following formulas (eq.27) and (eq.28) by replacing the rear wheel abnormality generated force F _{C_r} with the rear wheel side stabilizer generated force F _{stb_r.} It correct | amends to _Rb type _| formula and _Wb type _| formula.

As can be seen from equation (eq.27) and formula (eq.28), R _b equation to the rear wheel abnormality occurs force F _{C_r} the wheel-side stabilizer generated force F _{Stb_r} after in R-type, W _b equation W In this equation, the rear wheel side stabilizer generated force F _{stb_r} is _corrected to the rear wheel abnormal force generated F _{C_r} , respectively. The correction process performed in S230 corresponds to the correction means of the present invention. The R formula _{R b} expression at S230, after correction for W formula _{W b} expression, each wheel requested damping force calculation section 32 proceeds to S232, H-type, P-type, _{R b} wherein a _{W b} formula Using each wheel, the required damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , and F _{req_rl} are calculated. Thereafter, the process proceeds to S216.

If the determination result in S226 is No, that is, if the active stabilizer operation state is not diagnosed as “abnormal B”, each wheel required damping force calculation unit 32 proceeds to S234 in FIG. 6C. In S234, it is determined whether or not the operating state of the active stabilizer has been diagnosed as “abnormal C”. When “abnormal C” is diagnosed, the front wheel side operation state signal S _f is 1 and the rear wheel side operation state signal S _r is 0, that is, the front wheel side active stabilizer 20F is in an operation-free abnormality, and the rear This is a case where the wheel side active stabilizer 20R is normal. Since the front wheel side active stabilizer 20F is in an operation free abnormality, the front wheel side stabilizer generating force F _{stb_f} is actually zero. However, since the stabilizer ECU 40 calculates the front wheel side stabilizer generating force F _{stb_f} that opposes the roll moment under the assumption that the front wheel side active stabilizer 20F is normal, the front wheel side that is actually generated is calculated. The stabilizer generating force (= 0) is different from the front wheel side stabilizer generating force obtained by calculation. Therefore, unless the front wheel side stabilizer generating force F _{stb_f} included in the R and W formulas is set to 0, the appropriate required wheel damping force cannot be calculated. Therefore, if the operating state of the active stabilizer is "abnormal C" (S234: Yes), the process proceeds to S236, R-type and W R _c expression that expression in the following equation (eq.29) and formula (Eq.30 ) To the _Wc equation shown in FIG.

As can be seen from equation (eq.29) and formula (eq.30), R _c expression obtained by correcting the front-wheel-side stabilizer generated force F _{Stb_f} in R expression 0 formula, W _c expressions front side in the W-type This is an expression in which the stabilizer generating force F _{stb_f} is corrected to zero. The correction process performed in S236 corresponds to the correction means of the present invention. The R formula _{R c} type at S236, after correction for W formula _{W c} expression, each wheel requested damping force calculation section 32 proceeds to S238, H-type, P-type, _{R c} wherein a _{W c} formula Using each wheel, the required damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , and F _{req_rl} are calculated. Thereafter, the process proceeds to S216.

If the determination result in S234 is No, that is, if the active stabilizer operating state is not “abnormal C”, each wheel required damping force calculation unit 32 proceeds to S240. In S240, it is determined whether or not the operating state of the active stabilizer is diagnosed as “abnormal D”. When “abnormal D” is diagnosed, both the front wheel side operation state signal S _f and the rear wheel side operation state signal S _r are 1, that is, both the front wheel side active stabilizer 20F and the rear wheel side active stabilizer 20R are free to operate. This is an abnormal case. In this case, both the front wheel side stabilizer generating force F _{stb_f} and the rear wheel side stabilizer generating force F _{stb_r} are zero. Therefore, if the front wheel side stabilizer generated force F _{stb_f} and the rear wheel side stabilizer generated force F _{stb_r} included in the R and W formulas used for calculating the required damping force for each wheel are not set to zero, It is not possible to calculate the appropriate damping force required for each wheel. Therefore, if the operating state of the active stabilizer is "abnormal D" (S240: Yes), the process proceeds to S242, R-type and W R _d expression that expression in the following equation (eq.31) and formula (Eq.32 ) _Is corrected to the _Wd equation shown in FIG.

As can be seen from equation (eq.31) and formula (eq.32), R _d expression was corrected front-wheel-side stabilizer generated force F _{Stb_f} and the rear-wheel-side stabilizer generated force F _{Stb_r} in R expression both zero formula, W _d expression is an expression both corrected to 0 a front wheel side stabilizer generated force F _{Stb_f} and rear-wheel-side stabilizer generated force F _{Stb_r} in W type. The correction process performed in S242 corresponds to the correction means of the present invention. The R formula _{R d} expression at S242, after correction for W formula _{W d} expression, each wheel requested damping force calculation section 32 proceeds to S244, H-type, P-type, _{R d} wherein a _{W d} Formula Using each wheel, the required damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , and F _{req_rl} are calculated. Thereafter, the process proceeds to S216.

If the determination result in S240 is No, that is, if the active stabilizer operating state is not “abnormal D”, each wheel required damping force calculation unit 32 proceeds to S246. Then, in S246, it is determined whether or not the operating state of the active stabilizer has been diagnosed as “abnormal E”. When “abnormal E” is diagnosed, when the front wheel side operation state signal S _f is 1 and the rear wheel side operation state signal S _r is 2, that is, the front wheel side active stabilizer 20F is in an operation-free abnormality, the rear wheel This is a case where the side active stabilizer 20R has an operation lock abnormality. In this case, if the front wheel side stabilizer generated force F _{stb_f} included in the R type and W type is set to 0 and the rear wheel side stabilizer generated force F _{stb_r} is not changed to the rear wheel abnormal force generated force F _{C_r} , It is not possible to calculate the appropriate damping force required for each wheel using. Therefore, when the operating state of the active stabilizer is “abnormal E” (S246: Yes), first, in _S248 , the rear wheel abnormality occurrence force F C — _r is calculated based on the above equation (eq26). The calculation process of the rear wheel abnormal force generated F C — _{r performed in S248} corresponds to the abnormal force generated force calculation means of the present invention. Next, at S250, it corrects the R-type and W type in W _e formula shown in R _e formula and the following formula represented by the following formula (eq.33) (eq.34).

As can be seen from equation (eq.33) and formula (eq.34), R _e equation 0 a front wheel side stabilizer generated force F _{Stb_f} in R-type, rear wheel abnormality of the rear wheel side stabilizer generated force F _{Stb_r} an expression obtained by correcting the generated force F _{C_r,} W _e expression obtained by correcting the front-wheel-side stabilizer generated force F _{Stb_f} in W type 0, the rear wheel side stabilizer generated force F _{Stb_r} the rear wheel abnormality generated force F _{C_r} It is a formula. The correction process performed in S250 corresponds to the correction means of the present invention. The R formula _{R e} expression at S250, after correction for W formula _{W e} type, each wheel requested damping force calculation section 32 proceeds to S252, H-type, P-type, _{R e} type, the _{W e} formula The required damping forces F _{req_fr} , F _{req_fl} , F _{req_rr} , and F _{req_rl} for each wheel are calculated. Thereafter, the process proceeds to S216.

When the determination result of S246 is No, that is, when the active stabilizer operating state is not “abnormal E”, each wheel required damping force calculation unit 32 proceeds to S254 of FIG. 6D. In S254, it is determined whether or not the operating state of the active stabilizer is diagnosed as “abnormal F”. When “abnormal F” is diagnosed, when the front wheel side operation state signal S _f is 2 and the rear wheel side operation state signal S _r is 0, that is, the front wheel side active stabilizer 20F has an operation lock abnormality, the rear wheel side This is a case where the active stabilizer 20R is normal. Since the front wheel side active stabilizer 20F has an operation lock abnormality, the front wheel side active stabilizer 20F generates a front wheel abnormality occurrence force F C — _f . However, since the stabilizer ECU 40 calculates the front wheel side stabilizer generating force F _{stb_f} on the assumption that the front wheel side active stabilizer 20F is normal, the front wheel side stabilizer generating force (= F _{C_f} ) and the actually generated front wheel side stabilizer generating force are calculated. The front wheel side stabilizer generating force obtained by the above is different. Therefore, if the front wheel side stabilizer generating force F _{stb_f} included in the R and W formulas is not changed to the front wheel abnormal force generating force F _{C_f} instead of the value calculated by the stabilizer ECU 40, the stabilizer is generated correctly using these equations. It is impossible to calculate the appropriate damping force required for each wheel considering the force. Based on these facts, when the active stabilizer operating state is “abnormal F” (S254: Yes), first, in _S256 , the front wheel abnormality generated force F C — _f is calculated based on the above equation (eq.25). . The calculation process of the front wheel abnormality generated force F _{C —} f _{performed in} S254 corresponds to the abnormality generated force calculation means of the present invention. Next, in S258, the R and W equations are corrected to the R _f equation shown in the following equation (eq. 35) and the W _f equation shown in the following equation (eq. 36).

As can be seen from equation (eq.35) and formula (eq.36), R _f expression obtained by correcting the front-wheel-side stabilizer generated force F _{Stb_f} in R-type front wheels abnormality generated force F _{C_F} formula, W _f formula This is a formula in which the front wheel side stabilizer generated force F _{stb_f} in the W formula is corrected to a front wheel abnormal generated force F _{C_f} . The correction process performed in S258 corresponds to the correction means of the present invention. The R type at _{R f} type at S258, after correction for W formula _{W f} type, each wheel requested damping force calculation section 32 proceeds to S260, H-type, P-type, _{R f} type, the _{W f} formula Using each wheel, the required damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , and F _{req_rl} are calculated. Thereafter, the process proceeds to S216.

If the determination result in S254 is No, that is, if the active stabilizer operating state is not “abnormal F”, each wheel required damping force calculation unit 32 proceeds to S262. In S262, it is determined whether or not the operating state of the active stabilizer is diagnosed as “abnormal G”. When “abnormal G” is diagnosed, when the front wheel side operation state signal S _f is 2 and the rear wheel side operation state signal S _r is 1, that is, the front wheel side active stabilizer 20F is in an operation lock abnormality, the rear wheel side This is a case where the active stabilizer 20R is in an operation free abnormality. In this case, the front wheel side stabilizer generated force F _{stb_f} included in the R and W formulas used for calculating each wheel required damping force is changed to the front wheel abnormal force generated force F _{C_f} , and the rear wheel side stabilizer generated force F _{stb_r} Unless is set to 0, it is not possible to calculate an appropriate required damping force for each wheel using these equations. Therefore, when the operating state of the active stabilizer is “abnormal G” (S262: Yes), first, the front wheel abnormality occurrence force F C — _f is calculated based on the equation (eq.25) in S264. The calculation process of the front wheel abnormality generated force F _{C —} f _{performed in} S264 corresponds to the abnormality generated force calculation means of the present invention. Thereafter, in S266, the R formula and the W formula are corrected to the R _g formula shown in the following formula (eq. 37) and the W _g formula shown in the following formula (eq. 38).

As can be seen from equation (eq.37) and formula (eq.38), R _g expression the front-wheel-side stabilizer generated force F _{Stb_f} in R-type front wheels abnormality generated force F _{C_F,} rear-wheel-side stabilizer generated force F the _{Stb_r} 0, an expression obtained by correcting each, W _g expression the front-wheel-side stabilizer generated force F _{Stb_f} in W-type front wheels abnormality generated force F _{C_F,} zero the rear wheel side stabilizer generated force F _{Stb_r,} respectively This is a corrected formula. The correction process performed in S266 corresponds to the correction means of the present invention. After correcting the R equation to the R _g equation and the W equation to the W _g equation in S266, each wheel required damping force calculation unit 32 proceeds to S268, where the H equation, the P equation, the R _g equation, and the W _g equation are changed. Using each wheel, the required damping force F _{req_fr} , F _{req_fl} , F _{req_rr} , and F _{req_rl} are calculated. Thereafter, the process proceeds to S216.

If the determination result in S262 is No, that is, if the operating state of the active stabilizer is not “abnormal G”, the process proceeds to S270. In S270, each wheel required damping force calculation unit 32 determines whether or not the operating state of the active stabilizer is diagnosed as “abnormal H”. When “abnormal H” is diagnosed, when both the front wheel side operation state signal S _f and the rear wheel side operation state signal S _r are 2, that is, both the front wheel side active stabilizer 20F and the rear wheel side active stabilizer 20R are operated and locked. This is an abnormal case. In this case, the front wheel side stabilizer generated force F _{stb_f} included in the R type and W type is changed to the front wheel abnormal generated force F _{C_f} , and the rear wheel side stabilizer generated force F _{stb_r} is _changed to the rear wheel abnormal generated force F _{C_r} If this is not done, it is not possible to calculate an appropriate required damping force for each wheel using these equations. Therefore, when the operating state of the active stabilizer is “abnormal H” (S270: Yes), first, the front wheel abnormality generated force _{FC_f} is calculated based on the equation (eq.25) in S272, and then in S274. Based on the equation (eq.26), the rear wheel abnormal force generated F _{C_r} is calculated. The calculation process of the front wheel abnormality generated force F C — _f and the rear wheel abnormality generated force F C — _{r performed} in S272 and S274 corresponds to the abnormality generated force calculation means of the present invention. Thereafter, in S276, the R formula and the W formula are corrected to the R _h formula shown in the following formula (eq.39) and the W _h formula shown in the following formula (eq.40).

As can be seen from equation (eq.39) and formula (eq.40), R _h expression the front-wheel-side stabilizer generated force F _{Stb_f} in R-type front wheels abnormality generated force F _{C_F,} rear-wheel-side stabilizer generated force F the rear wheel abnormality occurs force F _{C_r} the _{Stb_r,} an expression obtained by correcting each, W _h expression the front-wheel-side stabilizer generated force F _{Stb_f} in W-type front wheels abnormality generated force F _{C_F,} rear-wheel-side stabilizer generated force _This is an expression in which F _{stb_r} is corrected to the rear wheel abnormality occurrence force F _{C_r} , respectively. The correction process performed in S276 corresponds to the correction means of the present invention. The R formula _{R h} expression at S276, after correction for W formula _{W h} formula, each wheel requested damping force calculation section 32 proceeds to S278, H-type, P-type, _{R h} wherein the _{W h} formula Calculate the required damping force for each wheel. Thereafter, the process proceeds to S216.

  If the determination result in S270 is No, the active stabilizer operating state is diagnosed as "abnormal I" or "abnormal J". When the abnormality of the active stabilizer is such abnormality, the content of the abnormality of the front wheel side active stabilizer 20F and / or the rear wheel side active stabilizer 20R is unknown. In such a case, proper correction cannot be made in correcting the R and W formulas. Therefore, in this case, control of the damping force characteristic of each damper is stopped. That is, if the determination result in S270 is No, the process proceeds to S218 and this process is terminated.

  After calculating each wheel required damping force by any one of S224, S232, S238, S244, S252, S260, S268, and S278, each wheel required damping force calculation unit 32 proceeds to S216, and calculates each wheel required damping force. Is output to each corresponding suspension actuator 132. Each suspension actuator 132 operates based on the input signal. The rotation of each corresponding valve 131 is controlled by the operation of the suspension actuator 132. Thereby, the damping force characteristic of each damper is controlled.

As described above, according to the present embodiment, the suspension ECU 30 controls the heave required damping force F _{req_H} that is a control target value of the damping force acting in the heave direction of the sprung member so as to suppress the vibration of the sprung member. Roll requested damping force F _{req_R} which is a control target value of damping force acting in the roll direction of the sprung member, and pitch requested damping force F _{req_P} which is control target value of damping force acting in the pitch direction of the sprung member Mode required damping force calculation unit 31 (mode required damping force calculation means), heave required damping force F _{req_H} , roll required damping force F _{req_R} and pitch required damping force calculated by the mode required damping force calculation unit 31. F _{req_P} , front wheel side stabilizer generating force F _{stb_f} and rear wheel side stabilizer generating force F generated by the front wheel side active stabilizer 20F and the rear wheel side active stabilizer 20R _Based on _{stb_r} , each wheel requested damping force (right front wheel side requested damping force F _{req_fr} , left front wheel side requested damping force F _{req_fl} , right rear wheel side requested damping force F, which is a control target value of the damping force generated by each damper each wheel required damping force calculating section 32 (each wheel required damping force calculating means) for calculating ( _{req_rr} , left rear wheel side required damping force _{Freq_rl} ). Then, based on each wheel required damping force calculated by each wheel required damping force calculation unit 32, the damping force characteristic of each damper is controlled. Thus, according to the present embodiment, the stabilizer generating force generated by the active stabilizers 20F, 20R is taken into account when calculating the required damping force for each wheel, so that the control of the damping force characteristics of the damper and the active stabilizer 20F, Interference of 20R roll rigidity control is prevented. Therefore, a reduction in roll suppression effect due to control interference is prevented.

Each wheel required damping force calculation unit 32 calculates each mode required damping force calculated by the mode required damping force calculation unit 31 (heave required damping force F _{req_H} , roll required damping force F _{req_R} , pitch required damping force F _{req_P} ). Each wheel required damping force and stabilizer generating force F _{stb_f} , F _{stb_r} , a relational expression (H, P, R expression), a stabilizer generating force constrained by a predetermined condition, and each Each wheel required damping force is calculated based on a constraint condition expression (W formula) representing a relationship with the wheel required damping force. Then, the damping force characteristic of each damper is controlled based on the calculated required wheel damping force. Thereby, damping force characteristic control in consideration of stabilizer generating force is achieved.

Further, the four required damping forces for each wheel include a heave-required damping force relational expression (H formula) that represents a balance between the required heave damping force F _{req_H} and the required damping force for each wheel, and a required pitch damping force. F _{Req_P} the pitch representing the balance of forces between the wheels required damping force - each wheel required damping force relationship between (P-type), the roll required damping force F _{req_r} each wheel required damping force and the stabilizer generated force _F stb_f, F Roll-required damping force relational expression (R-expression) representing the balance of force with _{stb_r} and each wheel required damping that is constrained by the condition that the sprung member HA does not twist (torsional force is 0). It is calculated from a constraint condition equation (W equation) representing the relationship between the force and the stabilizer generating force F _{stb_f} , F _{stb_r} . Thereby, the heave demand damping force, the pitch demand damping force, and the roll demand damping force are appropriately distributed to the four wheel demand damping forces in consideration of the stabilizer generating force.

Further, each wheel required damping force calculation unit 32 detects that the operation lock abnormality in which the operation of the front wheel side stabilizer actuator 23F and / or the rear wheel side stabilizer actuator 23R is locked is the front wheel side active stabilizer 20F and / or the rear wheel side active stabilizer 20R. When the operation of the stabilizer actuator is locked, the force generated at the time of abnormality is calculated based on the lock angle (specifically, the difference between the lock angle and the arm relative rotation angle), which is the rotation angle of the active stabilizer when the stabilizer actuator is locked. Generating means (S228, S248, S256, S264, S272, S274). In addition, among the three relational expressions (H, P, R expressions) and one constraint condition expression (W expression) used in calculating each wheel required damping force, the stabilizer generating forces F _{stb_f} and F _{stb_r} are included. Correction means (S222, S230, S236, S242, S250, S258, S266, S276) for correcting the expression (specifically, the R expression and the W expression) are included. Then, the correcting means corrects the R expression and the W expression by replacing the stabilizer generating force for the active stabilizer in which the operation lock abnormality has occurred with the abnormality generating force calculated by the abnormality generating force calculating means. With this correction, even when an operation lock abnormality occurs in the active stabilizer, the required damping force for each wheel is calculated in consideration of an appropriate force actually generated by the active stabilizer. By controlling the damping force characteristics of each damper based on the calculated required damping force for each wheel in this way, it is possible to suppress a reduction in the vibration suppressing effect of the sprung member HA even when the active stabilizer is malfunctioning. It is done.

  Further, the correction means corrects the R-type and the W-type so that the stabilizer generating force for the active stabilizer in which the operation free abnormality has occurred becomes 0 when the operation stabilizer has an operation free abnormality. Thereby, the damping force characteristic of each damper can be controlled based on the appropriate required damping force for each wheel calculated without considering the active stabilizer in which the operation free abnormality has occurred.

  In addition, as a constraint condition expression expressing the relationship between the stabilizer generating force and the required wheel damping force, the relationship between the stabilizer generating force and the required wheel damping force that are constrained by the condition that the torsional force of the sprung member is zero. An expression is used. For this reason, the vibration of the sprung member HA is effectively damped under the condition that the torsion of the sprung member HA does not occur.

  As mentioned above, although embodiment of this invention was described, this invention should not be limited to the said embodiment. For example, in the above-described embodiment, the vehicle in which the active stabilizer is mounted on the front wheel side and the rear wheel side of the vehicle has been described as an example. However, the present invention is also applied to a vehicle in which the active stabilizer is mounted on only one of them. be able to. Further, the present invention can also be applied to a vehicle in which an active stabilizer is mounted on either the front wheel side or the rear wheel side, and a general (conventional) stabilizer is mounted on the other side. In this case, the stabilizer generating force generated by the conventional stabilizer can be calculated based on the difference between the relative displacement amounts between the left and right sprung-road surfaces (that is, the difference between the stroke displacement amounts of the left and right dampers). Thus, the present invention can be modified without departing from the gist thereof.

10FR, 10FL, 10RR, 10RL ... Suspension device, 11 ... Spring, 12 ... Damper, 13 ... Variable throttle mechanism, 131 ... Valve, 132 ... Suspension actuator, 20F ... Front wheel side active stabilizer, 21FR, 21FL ... Front wheel side torsion bar, 22FR, 22FL ... front wheel side arm, 23F ... front wheel side stabilizer actuator (actuator), 20R ... rear wheel side active stabilizer, 21RR, 21RL ... rear wheel side torsion bar, 22RR, 22RL ... rear wheel side arm, 23R ... rear wheel side Stabilizer actuator (actuator), 30 ... Suspension ECU (damping force control device), 31 ... Mode required damping force calculation unit, 32 ... Each wheel required damping force calculation unit, 40 ... Stabilizer ECU, 51 ... Spring acceleration sensor, 5 ... road surface vertical acceleration sensor, 53 ... stroke sensor, 54 ... roll angle acceleration sensor, 55 ... pitch angle acceleration sensor, 56F ... front wheel rotational angle sensor, 56R ... rear wheel rotational angle sensor,
F _{req_H} ... _Heve demand damping force, F _{req_P} ... Pitch demand damping force, F _{req_R} ... Roll demand damping force, F _{req_fr} ... Right front wheel side demand damping force, F _{req_fl} ... Left front wheel side demand damping force, F _{req_rr} ... Right rear wheel Side required damping force, F _{req_rl} … Left rear wheel side required damping force, F _{stb_f} … Front wheel side stabilizer generating force, F _{stb_r} … Rear wheel side stabilizer generating force, F _{C_f} … Front wheel abnormality generating force, F _{C_r} … Rear wheel abnormality Force generated at the time, S _f ... Front wheel side operation state signal, S _r ... Rear wheel side operation state signal, φ _fa … Front wheel arm relative rotation angle, φ _ra … Rear wheel arm relative rotation angle, φ _fL … Front wheel lock angle, φ _rL … Rear wheel lock angle

Claims (8)

In a damping force control device that is applied to a vehicle on which an active stabilizer having an actuator is mounted and controls damping force characteristics of a damper of a suspension device attached to each wheel position of a sprung member,
In order to suppress the vibration of the sprung member, the heave required damping force that is the control target value of the damping force acting in the heave direction of the sprung member and the control target value of the damping force that acts in the roll direction of the sprung member Mode required damping force calculation means for calculating a certain roll required damping force and a pitch required damping force which is a control target value of the damping force acting in the pitch direction of the sprung member,
A control target of the damping force generated by each damper based on the heave requested damping force, the roll requested damping force, the pitch requested damping force calculated by the mode requested damping force calculation means, and the stabilizer generating force generated by the active stabilizer. Each wheel required damping force calculating means for calculating each wheel required damping force which is a value;
And a damping force control device for controlling a damping force characteristic of each damper based on each wheel requested damping force calculated by each wheel requested damping force calculating means. The damping force control apparatus according to claim 1,
Each wheel required damping force calculating means includes a heave required damping force, a roll required damping force, a pitch required damping force calculated by the mode required damping force calculating means, and each wheel required damping force and the stabilizer generating force. The required damping force for each wheel is calculated based on a relational expression that represents a balance of the power of each wheel and a constraint conditional expression that represents the relationship between the stabilizer generating force that is constrained by a predetermined condition and the required damping force for each wheel. A damping force control device. The damping force control device according to claim 2,
Each wheel required damping force calculation means,
Based on a lock angle, which is a rotation angle of the active stabilizer at the time when the operation of the actuator is locked, when the operation lock abnormality in which the operation of the actuator is locked occurs in the active stabilizer, the operation lock An abnormal-time generation force calculating means for calculating an abnormal-time generation force that is a stabilizer generation force generated by the active stabilizer that is abnormal; and
Correction means for correcting the relational expression and the constraint condition expression based on the abnormal-time generated force calculated by the abnormal-time generated force calculating means;
A damping force control device comprising: The damping force control apparatus according to claim 3,
The abnormal-time generation force calculation means uses the twist state of the active stabilizer whose rotation angle is the lock angle as a reference state, and based on the twist amount when the active stabilizer is further twisted from the reference state, A damping force control device, characterized by calculating an abnormal force. The damping force control device according to any one of claims 2 to 4,
The correction means corrects the relational expression and the constraint condition expression so that the stabilizer generating force becomes zero when an operation-free abnormality in which the active stabilizer idles occurs. Force control device. The damping force control apparatus according to any one of claims 2 to 5,
The above relational expression expresses the balance between the heave-required damping force relation of each wheel and the balance between the required force of each wheel and the required damping force of each wheel. It is a roll-required damping force relational expression representing a balance between a pitch-required damping force relational expression for each wheel, and a roll required damping force, a force required for each wheel, and the stabilizer generating force, Damping force control device. The damping force control apparatus according to any one of claims 2 to 6,
2. The damping force control apparatus according to claim 1, wherein the constraint condition expression represents a relationship between the stabilizer generating force that is restrained by a condition that the torsional force of the sprung member is zero and each wheel required damping force. The damping force control apparatus according to any one of claims 1 to 7,
The active stabilizer includes at least a front wheel side active stabilizer connected to a right front wheel and a left front wheel of a vehicle or a rear wheel side active stabilizer connected to a right rear wheel and a left rear wheel of the vehicle. Damping force control device.

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