WO2010122418A1

WO2010122418A1 - Roll control apparatus for vehicle

Info

Publication number: WO2010122418A1
Application number: PCT/IB2010/000917
Authority: WO
Inventors: Takashi Kurokochi
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2009-04-24
Filing date: 2010-04-23
Publication date: 2010-10-28
Also published as: JP2010254132A

Abstract

A vehicle roll control apparatus (100) includes: a first device (14, 16) capable of adjusting the roll rigidity of a vehicle (10); a second device (12FR, 12FL, 12RR, 12RL) capable of adjusting the stroke characteristic between the cabin and wheels of the vehicle; and control means (31, 32) for controlling the first device and the second device so as to suppress the roll moment that occurs on the vehicle. The control means controls the second device so as to adjust the stroke characteristic, in order to compensate for the adjustment delay made by the first device relative to the roll speed of the roll that occurs on the vehicle.

Description

ROLL CONTROLAPPARATUS FOR VEHICLE

BACKGROUND OF THE INVENTION

1. Field of the Invention [0001] The invention relates to the technical field of a roll control apparatus that makes suitable the maneuvering stability and the ride quality, for example, during the traveling of a vehicle.

2. Description of the Related Art [0002] As an apparatus of this kind, for example, Japanese Patent Application

Publication No. 2008-168875 (JP-A-2008-168875) describes an apparatus that corrects the target damping forces of left and right-wheel shock absorbers so as to decrease the roll of the vehicle when the target anti-roll moment exceeds a maximum anti-roll moment of the active stabilizer device. This application particularly describes that when the post-correction target damping force for at least one of the left and right wheels exceeds the maximum damping force of the shock absorber of the at least one wheel, the target damping force of the wheel whose excess damping force over the maximum damping force is greater in magnitude than that of the other wheel is subjected to a decreasing correction with the greater excess damping force, and the target damping force of the wheel opposite in the left-right direction to the wheel whose excess damping force is greater in magnitude is subjected to a decreasing correction with the greater one of the excess damping forces.

[0003] Japanese Patent Application Publication No. 2006-2563689 (JP-A-2006-2563689) describes an apparatus that determines a rate of change in the roll of the vehicle, and that controls the damping characteristic of a shock absorber to a higher damping side and causes torsional rigidity of the stabilizer device to be lower when the rate of change is large than when the rate of change is small.

[0004] Japanese Patent Application Publication No. 2006-7803 (JP-A-2006-7803) describes an apparatus that controls an active stabilizer device and an air spring respectively according to the amount of increase in the anti-roll moment caused by the active stabilizer device and the amount of increase in the anti-roll moment caused by the air spring, which are respectively calculated on the basis of the lateral acceleration of the vehicle. This patent application particularly describes that the amount of increase in anti-roll moment caused by the air spring is made smaller than the amount of increase in anti-roll moment caused by the active stabilizer device, when the lateral acceleration is small, rather than when the lateral acceleration is large.

[0005] However, the forgoing background technologies have a technical problem in the possibility of failing to sufficiently control the roll of the vehicle.

SUMMARY OF THE INVENTION

[0006] The invention provides a roll control apparatus for a vehicle which is capable of suitably controlling the roll of the vehicle.

[0007] A vehicle roll control apparatus in accordance with a first aspect of the invention includes: a first device capable of adjusting roll rigidity of a vehicle; a second device capable of adjusting stroke characteristic between wheels of the vehicle and a cabin of the vehicle; and control means for controlling the first device and the second device so as to suppress roll moment that occurs on the vehicle, wherein the control means controls the second device so as to adjust the stroke characteristic, in order to compensate for an adjustment delay made by the first device relative to roll speed of the roll that occurs on the vehicle.

[0008] In the vehicle roll control apparatus in accordance with the first aspect of the invention, the control means may include: target specific determination means for specifically determining a target anti-roll moment for suppressing the roll moment; detection means for detecting anti-roll moment that is produced by the first device; and adjustment delay specific determination means for specifically determining a difference between the specifically determined target anti-roll moment and the detected anti-roll moment, as the adjustment delay made by the first device.

[0009] A vehicle roll control apparatus in accordance with a second aspect of the invention includes: a variable stabilizer capable of adjusting roll rigidity of a vehicle; a variable suspension capable of adjusting damping force of a suspension mechanism of the vehicle; and control means for controlling the variable stabilizer and the variable suspension so as to suppress roll force that occurs on the vehicle, wherein the control means controls the variable suspension so that anti-roll force becomes large, when roll speed of the roll that occurs on the vehicle is fast.

[0010] A vehicle roll control apparatus in accordance with a third aspect of the invention includes: a variable stabilizer capable of adjusting roll rigidity of a vehicle; a variable suspension capable of adjusting damping force of a suspension mechanism of the vehicle; and control means for controlling the variable stabilizer and the variable suspension according to a first control command value for controlling the variable stabilizer, and a second control command value for controlling the variable suspension, wherein when the first control command value is large, the control means controls the variable suspension by changing the second control command value so that anti-roll force that suppresses the roll force that occurs on the vehicle becomes large.

[0011] A vehicle roll control apparatus in accordance with a fourth aspect of the invention includes: an active stabilizer that adjusts roll rigidity of a vehicle so that a roll characteristic approaches a target roll characteristic value; and an active suspension that adjusts stroke characteristic between wheels of the vehicle and a cabin of the vehicle, wherein the active suspension adjusts the stroke characteristic so as to produce anti-roll force that suppresses roll force that occurs on the vehicle, according to the target roll characteristic value, and the roll characteristic value given by the active stabilizer.

BRIEF DESCRIPTION OF THE DRAWINGS [0012] The foregoing and further features and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements, and wherein:

FIG 1 is a block diagram showing a construction of a vehicle in which a roll control apparatus in accordance with an embodiment of the invention is mounted;

FIG 2 is a schematic construction diagram that conceptually shows a construction of a rear suspension of the vehicle in accordance with the embodiment of the invention;

FIG 3 is a flowchart showing a control process of a stabilizer in accordance with the embodiment of the invention;

FIG 4 is a flowchart showing a following response delay process in accordance with the embodiment of the invention; and

FIG 5 is a flowchart that shows control processes for stabilizers and shock absorbers in accordance with a modification of the embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0013] Embodiments of a roll control apparatus for a vehicle in accordance with the invention will be described below.

[0014] A roll control apparatus for a vehicle in accordance with a first embodiment of the invention includes a first device capable of adjusting the roll rigidity of the vehicle, a second device capable of adjusting the stroke characteristic of the stroke between wheels and a cabin of the vehicle, and control means for respectively controlling the first device and the second device so as to suppress the roll moment that occurs on the vehicle, the control means controlling the second device so as to adjust the stroke characteristic, in order to compensate for the adjustment delay made by the first device relative to the roll speed of the roll that occurs on the vehicle.

[0015] According to the vehicle roll control apparatus in accordance with the embodiment, the first device is able to adjust the roll rigidity of the vehicle. The "roll rigidity" herein means a property that works to suppress roll of the vehicle by withstanding the roll moment that occurs on the vehicle. In the case where the first device is, for example, an active stabilizer, the adjustment of the roll rigidity is carried out by respectively adjusting the hardness of the stabilizer of the front wheels of the vehicle and the hardness of the stabilizer of the rear wheels of the vehicle.

[0016] The second device is able to adjust the stroke characteristic between the cabin and wheels of the vehicle. The "stroke characteristic between the cabin and wheels" means the characteristic of change in the distance between the cabin and wheels within the stroke between the cabin and the wheels (i.e., the suspension stroke"), and concretely means, for example, the damping force (or the damping coefficient) of the suspension, the elastic force (or the elastic coefficient) of the suspension, etc. In the case where the second device is, for example, an active suspension, the adjustment of the stroke characteristic is carried out mainly by adjusting the hydraulic pressure of the damper.

[0017] The control means that includes, for example, a memory, a processor, etc., controls the first device and the second device so as to suppress the roll moment that occurs on the vehicle. The term "so as to suppress the roll moment that occurs on the vehicle" means, for example, to cause force in the direction opposite the direction of the roll moment (i.e., anti-rolL moment).

[0018] Incidentally, in the vehicle roll control apparatus in accordance with the embodiment, the roll moment that occurs on the vehicle is suppressed by mainly adjusting the roll rigidity, for example, in order to improve the ride quality of the vehicle.

[0019] In the vehicle roll control apparatus in accordance with this embodiment, the control means controls the second device so that the stroke characteristic is adjusted, in order to compensate for the adjustment delay made by the first device relative to the roll speed of the roll that occurs on the vehicle. Specifically, in the case where the roll moment that occurs on the vehicle is suppressed by generating anti-roll moment through controlling the first device so as to adjust the roll rigidity, and where the roll speed is relatively fast so that delay occurs in the adjustment of the roll rigidity by the first device due to, for example, its mechanical performance or the like (i.e., a following response delay of the actual roll rigidity relative to the target roll rigidity), the shortfall in anti-roll moment that results from the adjustment delay that has occurred or is expected to occur is compensated for by controlling the second device so as to adjust the stroke characteristic.

[0020] According to studies by the present inventors, it is known that in the case where the ride quality of the vehicle is regarded as important, anti-roll moment is generated by mainly adjusting the roll rigidity while avoiding changes in the stroke characteristic as much as possible. Therefore, ideally, it is desirable that the roll moment that occurs on the vehicle be suppressed by generating anti-roll moment through adjusting only the roll rigidity. [0021] However, if an attempt to suppress the roll moment that occurs on the vehicle through the adjustment of only the roll rigidity is to be realized by, for example, improving the performance of an electric motor or the like of an active stabilizer as an example of the "first device" in accordance with the embodiment, the electric power consumed by the motor becomes very large due to the characteristics of the motor, and therefore the electric power source capability needs to be drastically improved in order to supply the electric power that is consumed by the motor. Thus, the realization of this attempt is very difficult.

[0022] On the other hand, as for an active stabilizer that has an electric motor or the like whose required performance is within a feasible range, a delay in the following response is likely to occur due to irregularities of a road surface, and the like, or when the vehicle is to evade an obstacle present in the traveling direction of the vehicle, or enters a corner at relatively high speed, etc. Another conceivable method is a method of adjusting the stroke characteristic only when a following response delay occurs. However, it has become clear that when a delay in the following response occurs, a simple adjustment of the stroke characteristic gives rise to a risk that the anti-roll moment occurring as a result of the adjustment of the stroke characteristic may be small in comparison with the degree of the delay in the following response (in this case, the roll of the vehicle will become larger than during the time of normal steering), or a risk that the anti-roll moment occurring as a result of the adjustment of the stroke characteristic may be large in comparison with the degree of the delay in the following response (in this case, the roll of the vehicle will be excessively suppressed).

[0023] However, in this embodiment, the control means controls the second device so that the stroke characteristic is adjusted, in order to compensate for the adjustment delay made by the first device relative to the roll speed of the roll that occurs on the vehicle. Concretely, by the control means, the degree of the delay in the adjustment performed by the first device is specifically determined, and the second device is controlled so as to bring about such a stroke characteristic that an anti-roll moment corresponding to the specifically determined degree of the adjustment delay occurs.

[0024] Therefore, the roll moment that occurs on the vehicle can be suppressed appropriately even in the case where the roll speed is relatively fast while the ride quality of the vehicle is regarded as important. As a result, even in the case where the roll speed is relatively fast, discomfort is not caused to, for example, the driver or the like of the vehicle, so that drivability of the vehicle can be maintained or improved.

[0025] Incidentally, the control means may include target specific determination means for specifically determining a target anti-roll moment for suppressing the roll moment, detection means for detecting the anti-roll moment caused by the first device, and adjustment delay specific determination means for specifically determining a difference between the specifically determined target anti-roll moment and the detected anti-roll moment as an adjustment delay made by the first device.

[0026] This construction makes it possible to relatively easily specifically determine the degree of the adjustment delay made by the first device, and therefore is very advantageous from a practical standpoint. The term "specific determination" in this embodiment is a concept that encompasses detection, estimation, calculation, derivation, identification, acquisition, etc.

[0027] The target specific determination means that includes, for example, a memory, a processor, etc., specifically determines a target anti-roll moment for suppressing the roll moment that occurs on the vehicle. Concretely, the target specific determination means specifically determines, for example, a target anti-roll moment such that the anti-roll moment in such a direction as to cancel out the roll moment that occurs on the vehicle increases, on the basis of the lateral acceleration of the vehicle. Incidentally, the target specific determination means also specifically determines, for example, a target roll rigidity distribution ratio regarding the front wheels, on the basis of, for example, the speed of the vehicle.

[0028] The detection means, for example, an acceleration sensor or the like, detects the anti-roll moment that is produced by the first device. Herein, the term "anti-roll moment produced by the first device" means, for example, an anti-roll moment that results from the control means controlling the first device on the basis of the target anti-roll moment regarding the front wheels and the target anti-roll moment regarding the rear wheels which are determined by the target anti-roll moment specifically determined by the target specific determination means, and the target roll rigidity distribution ratio regarding the front wheels. [0029] The adjustment delay specific determination means that includes, for example, a memory, a processor, etc., specifically determines a difference between the specifically determined target anti-roll moment and the detected anti-roll moment, as an adjustment delay (i.e., a following response delay) made by the first device.

[0030] A roll control apparatus for a vehicle in accordance with a second embodiment of the invention includes: a variable stabilizer capable of adjusting the roll rigidity of the vehicle; a variable suspension capable of adjusting the damping force of a suspension mechanism of the vehicle; and control means for controlling the variable stabilizer and the variable suspension so as to suppress the roll force that occurs on the vehicle. The control means controls the variable suspension so that anti-roll force becomes larger in the case where the roll speed of the roll that occurs on the vehicle is fast.

[0031] The vehicle roll control apparatus in accordance with this embodiment is able to suppress the roll force (i.e., roll moment) that occurs on the vehicle appropriately even in the case where the roll speed is relatively fast while the ride quality is regarded as important, as in the foregoing vehicle roll control apparatus in accordance with the first embodiment. As a result, even in the case where the roll speed is relatively fast, discomfort is not caused to, for example, the driver or the like of the vehicle, so that drivability of the vehicle can be maintained or improved.

[0032] The variable stabilizer is capable of adjusting the roll rigidity of the vehicle. The variable suspension is capable of adjusting the damping force of the suspension mechanism of the vehicle. For example, the control device that includes, for example, a memory, a processor, etc., controls the variable stabilizer and the variable suspension so as to suppress the roll force that occurs on the vehicle. [0033] Incidentally, the vehicle roll control apparatus in accordance with this embodiment, similar to the foregoing vehicle roll control apparatus in accordance with the first embodiment, suppresses the roll force that occurs on the vehicle by mainly adjusting the roll rigidity (i.e., by mainly controlling the variable stabilizer), in order to, for example, improve the ride quality of the vehicle. [0034] In the vehicle roll control apparatus in accordance with this embodiment, in particular, the control means controls the variable suspension so that the anti-roll force (i.e., the anti-roll moment) becomes larger in the case where the roll speed of the roll that occurs on the vehicle is fast. That is, the control means controls the variable suspension so that anti-roll force (e.g., an anti-roll force that compensates for the shortfall in anti-roll force that results from a following response delay that occurs on the variable stabilizer) occurs, in the case where the roll force that occurs on the vehicle is to be suppressed by generating anti-roll force through controlling the variable stabilizer so as to adjust the roll rigidity, and where the roll speed is relatively fast (concretely, for example, where a following response delay has occurred or is expected to occur on the variable stabilizer). [0035] The term "controls the variable suspension so that anti-roll force occurs" means to control the variable suspension so as to adjust the damping force to such a side that anti-roll force occurs. Besides, the control means controls the variable suspension so that the faster the roll speed that occurs on the vehicle, the greater the anti-roll force becomes. That is, the control means controls the variable suspension, for example, so that the anti-roll force produced by the variable suspension when the roll speed that occurs on the vehicle is a second roll speed that is faster than a first roll speed is larger than the anti-roll force produced by the variable suspension when the roll speed that occurs on the vehicle is the first certain roll speed.

[0036] Incidentally, the control means controls the variable suspension so that the variable suspension does not cause anti-roll force, for example, on the condition that the roll speed is slow. That is, the control means suppresses the roll force that occurs on the vehicle, by producing anti-roll force, for example, through the use of only the variable stabilizer, in the case where the roll speed is relatively slow. [0037] Whether the roll speed is fast or slow is determined according to, for example, the physical, mechanical, electrical or magnetic characteristic or the like of the variable stabilizer. Alternatively, whether the roll speed is fast or slow may also be determined by providing a pre-determined reference value that is referred to when it is determined whether the roll speed is fast or slow, and comparing the roll speed with the pre-determined reference value.

[0038] The "reference value" in this embodiment is a value which determines whether or not to control the variable suspension so that anti-roll force is caused by the variable suspension, and which is set beforehand as a fixed value, or as a variable value commensurate with a certain physical quantity or a certain parameter. It suffices that such a reference value is set in a manner in which, experimentally or experientially, or by simulation, a relation between the roll speed and a difference value between the target value for controlling the variable stabilizer and the actual output value provided by the variable stabilizer is found, and, on the basis of the found relation, the reference value is set at a roll speed that causes the difference value to reach an upper limit value of the allowable range of the difference value, or at a roll speed that is lower by a predetermined value than the roll speed that causes the difference value to reach an upper limit value.

[0039] A roll control apparatus for a vehicle in accordance with a third embodiment of the invention includes: a variable stabilizer capable of adjusting the roll rigidity of the vehicle; a variable suspension capable of adjusting the damping force of a suspension mechanism of the vehicle; control means that controls the variable stabilizer and the variable suspension according to a first control command value for controlling the variable stabilizer, and a second control command value for controlling the variable suspension. In the case where the first control command value is large, the control means controls the variable suspension by changing the second control command value so that the anti-roll force that suppresses the roll force that occurs on the vehicle increases.

[0040] The vehicle roll control apparatus in accordance with this embodiment, similar to the foregoing vehicle roll control apparatus in accordance with the first embodiment, is able to suppress the roll force that occurs on the vehicle appropriately even in the case where the roll speed is relatively fast while the ride quality of the vehicle is regarded as important. As a result, even in the case where the roll speed is relatively fast, discomfort is not caused to, for example, the driver or the like of the vehicle, so that drivability of the vehicle can be maintained or improved. [0041] The variable stabilizer is capable of adjusting the roll rigidity of the vehicle. The variable suspension is capable of adjusting the damping force of the suspension mechanism of the vehicle. The control means that includes, for example, a memory, a processor, etc., controls the variable stabilizer and the variable suspension according to the first control command value for use for controlling the variable stabilizer, and the second control command value for use for controlling the variable suspension.

[0042] Herein, the "first control command value" and the "second control command value" are, for example, target values for use for controlling the variable stabilizer and the variable suspension. Incidentally, the target value may be a physical quantity, or a certain parameter that indicates the physical quantity. Concretely, for example, the "first control command value" is a roll rigidity that is determined by the roll angle, the roll moment, the roll rate, etc., or a parameter that indicates the roll rigidity, and the "second control command value" is a damping force that is determined by the roll angle, the roll moment, the roll rate, etc, or a parameter that indicates the damping force.

[0043] Incidentally, the vehicle roll control apparatus in accordance with this embodiment, similar to the foregoing vehicle roll control apparatus in accordance with the first embodiment, suppresses the roll force that occurs on the vehicle by mainly adjusting the roll rigidity (i.e., by mainly controlling the variable stabilizer), in order to, for example, improve the ride quality of the vehicle.

[0044] In the vehicle roll control apparatus in accordance with this embodiment, in particular, the control means controls the variable suspension by changing the second control command value so that an anti-roll force that suppresses the roll force that occurs on the vehicle becomes larger in the case where the first control command value is large.

[0045] Specifically, the control means controls the variable suspension by changing the second control command value so that an anti-roll force that suppresses the roll force that occurs on the vehicle (concretely, for example, an anti-roll force that compensates for a shortfall in the anti-roll force that results from a following response delay that occurs on the variable stabilizer, or an anti-roll force that compensates for a shortfall in the anti-roll force that results from the target roll rigidity being greater than the upper limit value of the adjustable range of roll rigidity) occurs, in the case where the roll force that occurs on the vehicle is to be suppressed by generating anti-roll force through controlling the variable stabilizer so as to adjust the roll rigidity, and where the first control command value has become relatively large (concretely, for example, (i) the case where a delay in the roll rigidity adjustment by the variable stabilizer which results from, for example, the variable stabilizer's mechanical performance or the like, (i.e., a following response delay of the actual roll rigidity relative to the target roll rigidity indicated by the first control command value) has occurred or is expected to occur due to irregularities of the road surface, or when the vehicle evades an obstacle present in the traveling direction of the vehicle, or enters a corner at relatively high speed, or (ii) the case where the target roll rigidity indicated by the first control command value is greater than the upper limit value of the range of the roll rigidity that is adjustable by the variable stabilizer).

[0046] The control means changes the second control command value so that, for example, the greater the first control command value, the greater the anti-roll force produced by the variable suspension for suppressing the roll force that occurs on the vehicle, in the case where the roll force that occurs on the vehicle is to be suppressed by generating the anti-roll force through controlling the variable stabilizer so as to adjust the roll rigidity.

[0047] That is, the control means changes the second control command value so that the second control command value that indicates the anti-roll force that is to be produced by the variable suspension when the roll force occurring on the vehicle is equal to a second roll force that is greater than a first roll force becomes greater than the second control command value that indicates the anti-roll force that is to be produced by the variable suspension when the roll force occurring on the vehicle is equal to the first roll force (in this case, the first control command value is greater than in the case where the roll force occurring on the vehicle is equal to the first roll force).

[0048] Whether or not the first control command value is large is determined according to, for example, the physical, mechanical, electrical, or magnetic characteristic or the like of the variable stabilizer. Alternatively, it is also permissible to determine beforehand a reference value that is referred to when it is determined whether or not the first control command value is large, and to compare the thus-determined reference value and the first control command value in order to determine whether or not the first control command value is large. [0049] The "reference value" in accordance with this embodiment is a value which determines whether or not to change the second control command value so that the variable suspension produces anti-roll force, and which is set beforehand as a fixed value, or as a variable value commensurate with a certain physical quantity or a certain parameter. It suffices that such a reference value is set in a manner in which, experimentally or experientially, or by simulation, a relation between a difference value between the rate of change in the roll rigidity indicated by the first control command value and the upper limit value of the rate of change in the roll rigidity restricted by the mechanical performance of the variable stabilizer or a value that is smaller than the upper limit value by a predetermined value, and the degree of the driving stability that results from the different value is found, and, on the basis of the found relation, the reference value is set at the first control command value that indicates such a rate of change in the roll rigidity that the degree of the driving stability reaches a limit of the allowable range. Alternatively, it suffices to simply set the reference value at the first control command value that indicates the upper limit value of the rate of change in the roll rigidity that is restricted by the mechanical performance of the variable stabilizer, or that indicates a value that is smaller than the upper limit value by a predetermined value.

[0050] A roll control apparatus for a vehicle in accordance with a fourth embodiment of the invention includes: an active stabilizer that adjusts the roll rigidity of the vehicle so that a target roll characteristic value is approached; and an active suspension that adjusts the stroke characteristic between wheels of the vehicle and the cabin thereof. The active suspension adjusts the stroke characteristic so that an anti-roll force that suppresses the roll force that occurs on the vehicle is produced, according to the target roll characteristic value, and the roll characteristic value given by the active stabilizer.

[0051] The vehicle roll control apparatus in accordance with this embodiment, similar to the foregoing vehicle roll control apparatus in accordance with the first embodiment, is able to suppress the roll force that occurs on the vehicle appropriately even in the case where the roll speed is relatively fast while the ride quality of the vehicle is regarded as important. As a result, even in the case where the roll speed is relatively fast, discomfort is not caused to, for example, the driver or the like of the vehicle, so that drivability of the vehicle can be maintained or improved.

[0052] The active stabilizer adjusts the roll rigidity of the vehicle so that a target roll characteristic value is approached. The active suspension adjusts the stroke characteristic between wheels of the vehicle and the cabin thereof. The term "target roll characteristic value is approached" means that the post-adjustment roll rigidity is nearer by any amount to the target roll characteristic value than the pre-adjustment roll rigidity, and is not limited to the post-adjustment roll rigidity becoming equal to the target roll characteristic value. The "target roll characteristic value" means a value which is provided for generating an anti-roll force that suppresses the roll force that occurs on the vehicle, and which is determined by the target roll angle, the target roll moment, and the target roll rate.

[0053] Incidentally, the vehicle roll control apparatus in accordance with this embodiment, similar to the foregoing vehicle roll control apparatus in accordance with the first embodiment, suppresses the roll force that occurs on the vehicle by mainly adjusting the roll rigidity (i.e., by mainly controlling the active stabilizer), in order to, for example, improve the ride quality of the vehicle.

[0054] In the vehicle roll control apparatus in accordance with this embodiment, in particular, the active suspension controls the stroke characteristic so that an anti-roll force that suppresses the roll force that occurs on the vehicle is produced, according to the target roll characteristic value, and the roll characteristic value determined by the active stabilizer. The term "controls the stroke characteristic so that an anti-roll force is produced, according to the target roll characteristic value, and the roll characteristic value determined by the active stabilizer" means, for example, that, according to a difference value between the target roll characteristic value, and a roll characteristic value resulting from the roll rigidity adjusted by the active stabilizer, the stroke characteristic is adjusted so that an anti-roll force that compensates for the difference value is produced.

[0055] Concretely, for example, the active suspension adjusts the stroke characteristic so that the greater the difference value, the greater anti-roll force the active suspension provides. Incidentally, the cases where the difference value occurs include the case where the roll speed is relatively fast, and where a following response delay in the roll rigidity results from, for example, the mechanical performance or the like of the active stabilizer. [0056] The operation and other advantages of the foregoing first to fourth embodiments will become apparent from preferred embodiments described below.

[0057] Hereinafter, a preferred embodiment of a roll control apparatus for a vehicle in accordance with the invention will be described with reference to FIG 1 to FIG. 4. [0058] Firstly, a vehicle in which a roll control apparatus in accordance with this embodiment is mounted will be described with reference to FIG 1 and FIG 2. FIG 1 is a block diagram showing a construction of the vehicle in which the roll control apparatus in accordance with the embodiment is mounted, and FIG 2 is a schematic construction diagram that conceptually shows a construction of a rear suspension in the vehicle in accordance with the embodiment. Incidentally, in FIG 1 and FIG 2, only members and the like that are directly related to the embodiment are shown, and other members and the like are omitted from the illustration, for the sake of convenience in illustration and description. [0059] Referring to FIG 1, a vehicle 10 includes front wheels FR and FL, and rear wheels RR and RL. A roll control apparatus 100 in accordance with this embodiment includes stabilizer devices 14 and 16, shock absorbers 22FR, 22FL, 22RR and 22RL, a stabilizer ECU (Electronic Control Unit) 31, AVS (Adaptive Variable Suspension) ECU 32, a longitudinal acceleration sensor 41, a lateral acceleration sensor 42, a vertical acceleration sensor 43, a vehicle speed sensor 44, a stroke sensor 45, a steering angle sensor 46, and rotation angle sensors 47F and 47R.

[0060] The stabilizer device 14 is provided between the front wheels FR and FL. The stabilizer device 14 has an actuator 14AC, and stabilizer bars 14AR and 14AL. An end of the stabilizer bar 14AR is linked to a suspension member 12FR of the front wheel FR, and an end of the stabilizer bar 14AL is linked to a suspension member 12FL of the front wheel FL.

[0061] During the action of the stabilizer device 14, the forces that suppress the bounding and rebounding of the front wheels FR and FL in mutually opposite phases due to torsional stress of the stabilizer bars 14AR and 14AL are changed as the stabilizer bars 14AR and 14AL are relatively rotationally driven by the actuator 14AC, whereby the anti-roll moments given to the vehicle 10 at the positions of the front wheels FR and FL are increased or decreased, so that the roll of the vehicle body on the front wheel side is suppressed.

[0062] On the other hand, the stabilizer device 16 is provided between the rear wheels RR and RL. The stabilizer device 16 has an actuator 16AC, and stabilizer bars 16AR and 16AL. An end of the stabilizer bar 16AR is linked to a suspension member 12RR of the rear wheel RR, and an end of the stabilizer bar 16AL is linked to a suspension member 12RL of the rear wheel RL.

[0063] During the action of the stabilizer device 16, the forces that suppress the bounding and rebounding of the rear wheels RR and RL in mutually opposite phases due to torsional stress of the stabilizer bars 16AR and 16AL are changed as the stabilizer bars 16AR and 16AL are relatively rotationally driven by the actuator 16AC, whereby the anti-roll moments given to the vehicle 10 at the positions of the rear wheels RR and RL are increased or decreased, so that the roll of the vehicle body on the rear wheel side is suppressed.

[0064] The actuators 14AC and 16AC of the stabilizer devices 14 and 16, respectively, are controlled by the stabilizer ECU 31, for example, by the stabilizer ECU 31 controlling the control current to motors or the like. Incidentally, with regard to the construction and the actions of a so-called active stabilizer that stabilizes behaviors of the vehicle 10 by relative rotation of the stabilizer bars 14AR and 14AL or the stabilizer bars 16AR and 16AL which is obtained by the stabilizer ECU 31 controlling the driving of a corresponding one of the actuators 14AC and 16AC, it is possible to apply various known manners or modes of the construction and the actions. However, such various known manners or modes are omitted from the description, for the purpose of avoiding complicated descriptions.

[0065] Incidentally, the "stabilizer devices 14 and 16" and the "stabilizer ECU 31" in accordance with this embodiment are examples of a "first device", a "variable stabilizer", and an "active stabilizer" in accordance with the invention. [0066] Incidentally, the characteristics of the stabilizer devices 14 and 16 may be the same, or may also be different from each other. For example, in a vehicle in which a power train (i.e., an engine, an inverter, a battery, a fuel cell (FC), etc.) is mounted on a front wheel side, the rigidity characteristic of the front wheel-side stabilizer device (the stabilizer device 14 in this embodiment) may be higher than that of the rear wheel-side stabilizer device (the stabilizer device 16 in this embodiment). Examples of the method of heightening the rigidity characteristic of a stabilizer device include a method of changing the rigidity of the stabilizer bars, a method of changing the actuator (a motor thereof), a method of changing the voltage applied to the actuator, etc.

[0067] The actuators 14AC and 16AC of the stabilizer devices 14 and 16 are respectively controlled by, for example, PWM (Pulse Width Modulation). Concretely, for example, the actuators 14AC and 16AC are respectively controlled by controlling the duty ratio (i.e., the ratio of the pulse width to the pulse period) within the range of effective voltage of ±46 V. [0068] The electric motors of the stabilizer devices 14 and 16 are supplied with, for example, direct-current electric power. Therefore, in the active stabilizer, since the target anti-roll moment changes momentarily, the source voltage supplied to the motor needs to be changed all the time in order to change the actual anti-roll moment (i.e., in order to change the amount of torsion of the stabilizer bars). However, it is difficult to change the source voltage itself all the time. Therefore, in this embodiment, the average value of the power source voltage is controlled by controlling the duty ratio as described above. That is, by controlling the duty ratio, the speed of the motor can be changed relatively easily.

[0069] Incidentally, the duty ratio is determined according to the deviation between the actual roll moment or the actual anti-roll moment and the target roll moment or the target anti-roll moment for controlling the stabilizer devices 14 and 16. Concretely, for example, the duty ratio is determined by multiplying the deviation between the target roll moment (or the target anti-roll moment) and the actual roll moment (or the actual anti-roll moment), and an integrated value of the deviation by a predetermined gain (e.g., a proportional gain and an integral gain). That is, the duty ratio is determined by a so-called PI control. In this case, for example, the duty ratio is determined so that the larger the deviation, the larger the duty ratio becomes (i.e., the higher the source voltage becomes).

[0070] The control of the stabilizer devices 14 and 16 may be a feedback control, or may also be a feed-forward control. Alternatively, the control may also be a combination of a feedback control and a feed-forward control.

[0071] Incidentally, in the case where the vehicle 10 is an electric vehicle (EV) that has only an electric motor as its drive power source of the vehicle 10, or is a hybrid vehicle (HV) that has an engine and a motor for driving the vehicle 10, the vehicle 10 is equipped with a high-voltage battery (e.g., of 200 to 300 V), and a low-voltage battery (e.g., of 12 V). Then, when the actuators 14AC and 16AC are controlled, the voltage of the high- voltage battery is lowered to, for example, 46 V, for use for the control. This construction makes it possible to improve, for example, the response of the stabilizer devices 14 and 16.

[0072] In the case where the vehicle 10 is a vehicle that has only an engine as its drive power source, the vehicle 10 is equipped with only a low-voltage electric power source (e.g., of 12 V), for example, a lead battery, or the like. Then, when the actuators 14AC and 16AC are controlled, the voltage of the low- voltage electric power source is raised to, for example, 46 V, for use for the control. This construction will lower the voltage transformation loss, and therefore is very advantageous from a practical standpoint.

[0073] The construction of the rear suspension of the vehicle 10 will be described with reference to FIG 2. In FIG 2, it is assumed that a near side corresponds to the front of the vehicle 10. Besides, in the embodiment, it is assumed that the left and right constructions of the rear suspension are equivalent to each other, and the description of a site or the like for the rear left wheel also serves as the description of a corresponding site or the like for the rear right wheel unless otherwise mentioned. Besides, replacement of "RL" in the reference characters of sites or the like for the rear left wheel with "RR" makes the reference characters that represent corresponding sites or the like for the rear right wheel.

[0074] In FIG 2, the rear left wheel RL is supported at an inner side in the vehicle width direction by an upper arm 23RL and a lower arm 24RL that are respectively supported so as to be pivotable up and down. That is, the vehicle 10 adopts so-called double wishbone-type suspensions. A shock absorber 22RL extending in an up-down direction in FIG 2 and slightly inclined inward in the vehicle width direction is fixed to the lower arm 24RL.

[0075] The upper arm 23RL and the lower arm 24RL are interlinked by a knuckle joint 25RL that is linked to ball joints (whose reference characters are not shown) that are formed on outer-side end portions of the two arms which are located outward in the vehicle width direction. The rear left wheel RL (more precisely, an inner wheel of the rear left wheel RL) is fixed to the knuckle joint 25RL.

[0076] The upper arm 23RL and the lower arm 24RL are constructed so as to move up and down following up-down movements of the rear left wheel RL commensurate with the traveling state of the vehicle 10. The impacts of up-down movements of the arms are dumped due to the damping force of the shock absorber 22RL, so that generally the transmission of impacts from the road surface or the up-down movements of the vehicle 10 as a whole are suppressed. [0077] The shock absorber 22RL has a cylinder, and a piston that is fit to the cylinder for reciprocating movements although not shown in the drawing. The piston is provided with an elongation-side damping force generation valve, and a contraction-side damping force generation valve. The damping coefficient of the shock absorber 22RL is changed by an actuator increasing or decreasing the degree of opening of each of the elongation-side damping force generation valve and the contraction-side damping force generation valve in a multi-step manner over a plurality of control steps.

[0078] Incidentally, the higher the control step, the smaller the degree of opening of each of the elongation-side damping force generation valve and the contraction-side damping force generation valve becomes, and therefore the higher the damping coefficient becomes. Besides, the elongation-side damping force is greater than the contraction-side damping force. Furthermore, the shock absorber 22RL may be a shock absorber whose damping coefficient is continuously changed by the continuous increase or decrease of the degrees of opening of the elongation-side damping force generation valve and the contraction-side damping force generation valve. [0079] The shock absorber 22RL generates damping force according to the damping coefficient and the speed of the piston relative to the cylinder as the rear left wheel RL bounds and rebounds. In this manner, the shock absorber 22RL damps the oscillations of the vehicle body, and suppresses changes in the posture of the vehicle body when the vehicle 10 is accelerating or cornering. [0080] An end portion of the stabilizer bar 16AL is fixed to a platy bar mount 26RL that is fixed to the knuckle joint 25RL. Therefore, when the stabilizer bar 16AL pivots, the distance between the rear left wheel RL and the vehicle body of the vehicle 10 changes, and thus the posture of the vehicle 10 changes. The stabilizer device 16, as described above, is able to suppress the behavior of the vehicle 10 in the roll direction (i.e., roll of the vehicle 10) according to the relative rotation angle between the stabilizer bar 16AL and the stabilizer bar 16AR.

[0081] Incidentally, the suspension member 12RL (see FIG 1) includes the shock absorber 22RL, the upper arm 23RL, the lower arm 24RL, the knuckle joint 25RL, and the bar mount 26RL.

[0082] The suspension in accordance with the embodiment is not limited to a double wishbone-type suspension, but may also be any known type suspension, for example, a McPherson strut-type suspension, a trailing arm-type suspension, etc.

[0083] The construction of a front suspension of the vehicle 10, although not shown in the drawing, is substantially the same as the construction of the rear suspension shown in FIG 2.

[0084] Referring back to FIG 1, the control steps of the shock absorbers 22FR, 22FL, 22RR and 22RL, that is, the degrees of opening of each of the elongation-side damping force generation valve and the contraction-side damping force generation valve, are controlled by the AVS ECU 32 controlling the control current to the actuators that respectively drive the elongation-side damping force generation valve and the contraction-side damping force generation valve.

[0085] Incidentally, with regard to the construction and actions of a so-called active suspension that stabilizes behaviors of the vehicle 10 by damping forces of the shock absorbers 22FR, 22FL, 22RR and 22RL that are obtained by the AVS ECU 32 controlling the driving of the shock absorbers 22FR, 22FL, 22RR and 22RL, it is possible to apply various known manners or modes of the construction and the actions. However, such various known manners or modes are omitted from the description, for the purpose of avoiding complicated descriptions. [0086] Incidentally, the "shock absorbers 22FR, 22FL, 22RR and 22RL" and the

"AVS ECU 32" in accordance with this embodiment are examples of a "second device", a

"variable suspension", arid an "active suspension" in accordance with the invention.

Besides, the "stabilizer ECU 31" and the "AVS ECU 32" in accordance with this embodiment are examples of "control means" in accordance with the invention.

[0087] As shown in FIG 1, signals input to the stabilizer ECU 31 are a signal that shows the lateral acceleration Gy of the vehicle 10 detected by the lateral acceleration sensor 42, a signal that shows the vehicle speed v detected by the vehicle speed sensor 44, and signals that show the actual rotation angles φf and φr of the actuators 14AC and 16AC detected by the rotation angle sensors 47F and 47R.

[0088] On the other hand, signals input to the AVS ECU 32 are a signal that shows the longitudinal acceleration Gx of the vehicle 10 detected by the longitudinal acceleration sensor 41, signals that show the vertical accelerations Gzi (i=fr, £1, rr, rl) of sites of the vehicle that correspond to the wheels which are detected by the vertical acceleration sensor 43, signals that show the strokes Xi (i=fr, fl, rr, rl) of the wheels which are detected by the stroke sensor 45, and a signal that shows the steering angle θ detected by the steering angle sensor 46.

[0089] Incidentally, the longitudinal acceleration sensor 41 detects the longitudinal acceleration Gx, with the direction of the acceleration of the vehicle 10 being defined as positive. The lateral acceleration sensors 42 and the steering angle sensor 46 detect the lateral acceleration Gy and the steering angle θ, respectively, with the positive sign given to the values that occur when the vehicle 10 turns right. The vertical acceleration sensor 43 detects the vertical accelerations Gzi of the vehicle body 10, with the upward acceleration defined as positive and the downward acceleration defined as negative. The stroke sensor 45 detects the strokes Xi of the wheels with the positive sign given to the strokes of the wheels in the bound direction, and the positive sign given to the strokes of the wheels in the rebound direction. The rotation angle sensors 47F and 47R detects the rotation angles φf and φr, respectively, with the negative sign given to the values in such a direction as to decrease the roll of the vehicle body when the vehicle 10 turns left.

[0090] Next, a control process of the stabilizers 14 and 16 and the shock absorbers 22FR, 22FL, 22RR and 22RL which is executed mainly during travel of the vehicle 10 in which a roll control apparatus 100 constructed as described above is mounted will be described with reference to the flowcharts shown in FIG. 3 and FIG 4. Incidentally, this control process is executed periodically, for example, at every several microseconds to several ten microseconds, or the like.

[0091] Referring to FIG 3, the stabilizer ECU 31 firstly receives the signal that shows the lateral acceleration Gy of the vehicle 10 detected by the lateral acceleration sensor 42, the signal that shows the vehicle speed v detected by the vehicle speed sensor

44, the signals that show the actual rotation angles φf and φr of the actuators 14AC and

16AC detected by the rotation angle sensors 47F and 47R, respectively (step SlOl).

[0092] Next, the stabilizer ECU 31 computes a target anti-roll moment Mat of the vehicle 10 so that the anti-roll moment in such a direction as to cancel out the roll moment that acts on the vehicle 10 increases, on the basis of the lateral acceleration Gy of the vehicle 10 (step S102), and computes a target roll rigidity distribution ratio Rmf of the front wheels on the basis of the vehicle speed v (step S 103). .

[0093] Next, the stabilizer ECU 31 computes a target anti-roll moment Matf of the front wheels and a target anti-roll moment Matr of the rear wheels on the basis of the target anti-roll moment Mat, and the target roll rigidity distribution ratio Rmf of the front wheels (step S104). Incidentally, as for the anti-roll moment, the positive sign is given to the anti-roll moment in the direction in which the anti-roll moment is to be generated when the vehicle 10 turns left.

[0094] Next, the stabilizer ECU 31, on the basis of the target anti-roll moments Matf and Matr, computes target rotation angles φft and φrt of the actuators 14AC and 16AC of the stabilizer devices 14 and 16, respectively (step S 105). Subsequently, the stabilizer ECU 31 controls the actuators 14AC and 16AC so that the rotation angles of the actuators 14AC and 16AC reach the target rotation angles φft and φrt, respectively (step S 106). Incidentally, the "target rotation angles φft and φrt" in accordance with this embodiment are examples of a "first control command value" in accordance with the invention.

[0095] Next, the stabilizer ECU 31 determines whether or not a following response delay has occurred on at least one of the stabilizer devices 14 and 16 (step S 107). If it is determined that a following response delay has occurred (YES in step S 107), a following response delay process described below is executed (step S200). On the other hand, if it is determined that a following response delay has not occurred (NO in step S 107), the process is returned and the start of the process is suspended, and thus a waiting state is entered, in other words, execution of the process of step SlOl is suspended, and thus a waiting state is maintained, until the next timing of starting the process that is uniquely determined by the predetermined execution period.

[0096] Incidentally, it suffices to determine whether or not a following response delay has occurred, by, for example, determining whether or not the roll speed of the vehicle 10 is greater than a first threshold value that is determined beforehand as a roll speed such that a following response delay is expected to occur. Alternatively, it also suffices to determine whether or not a following response delay has occurred, by determining whether or not at least one of the target rotation angles φft and φrt is greater than a second threshold value that is determined beforehand as a rotation angle at which a following response delay is expected to occur. [0097] Incidentally, the "target anti-roll moment Mat", the "target roll rigidity distribution ratio Rmf of the front wheels", the "target anti-roll moment Matf of the front wheels", and the "target anti-roll moment Matr of the rear wheels" in accordance with the embodiment are examples of a "target roll characteristic value" in accordance with the invention. [0098] Referring to FIG 4, the stabilizer ECU 31, after determining in step S107

(see FIG 3) that a following response delay has occurred (YES in step S 107), computes a following response delay anti-roll moment (step S211). Concretely, for example, the stabilizer ECU 31 computes a difference value between the target anti-roll moment Mat and the actual anti-roll moment, as a following response delay anti-roll moment. [0099] Incidentally, it suffices to determine an actual anti-roll moment, for example, on the basis of the lateral acceleration Gy detected by the lateral acceleration sensor 42, the vehicle speed v detected by the vehicle speed sensor 44, the actual rotation angles φr and φr of the actuators 14AC and 16AC detected by the rotation angle sensors 47F and 47R, respectively.

[0100] Next, the stabilizer ECU 31 sends a signal that shows the following response delay anti-roll moment, to the AVS ECU 32, for example, by CAN (Controller Area Network) communication, or the like (step S212).

[0101] Next, the AVS ECU 32 receives from the stabilizer ECU 31 the signal that shows the following response delay anti-roll moment (step S221), and computes a target damping force on the basis of the following response delay anti-roll moment (step S222). Incidentally, the damping force in an upward direction is defined as positive.

[0102] Concretely, for example, the AVS ECU 32 computes a target increase-decrease damping force by calculating a damping coefficient such that the multiplication product of the roll rate and the damping coefficient becomes equal to a following response delay anti-roll moment. That is, the AVS ECU 32 computes a damping coefficient by dividing the following response delay anti-roll moment by the roll rate, that is, (following response delay anti-roll moment/roll rate), and computes a target increase-decrease damping force. [0103] Herein, the "target increase-decrease damping force" is a value for correcting or modifying the basic target damping force. Therefore, a value obtained by adding the target increase-decrease damping force to the basic target damping force becomes a final target damping force. Incidentally, the basic target damping force is calculated in a known manner on the basis of the longitudinal acceleration Gx of the vehicle 10, with respect to each of the shock absorbers 22FR, 22FL, 22RR and 22RL.

[0104] Furthermore, the AVS ECU 32 computes a differential value Xdi (i=fr, fl, rr, rl) of the stroke Xi detected by the stroke sensor 45, as a stroke speed of each of the wheels, and computes a target control step of each of the shock absorbers 22FR, 22FL, 22RR and 22RL, on the basis of the target damping force and the stroke speed. [0105] Next, the AVS ECU 32 controls the shock absorbers 22FR, 22FL, 22RR and 22RL so that the control step of each of the shock absorbers 22FR, 22FL, 22RR and 22RL is at the target control step thereof (step S223), which is an example of a "second control command value" in accordance with the invention. [0106] Thus, in this embodiment, the following response delay anti-roll moments that show the degrees of the following response delay of the stabilizer devices 14 and 16, and the damping forces of the shock absorbers 22FR, 22FL, 22RR and 22RL are determined so as to produce anti-roll moments that compensate for the specifically determined following response delay anti-roll moments of the stabilizer devices 14 and 16.

[0107] That is, the roll control apparatus 100 controls the shock absorbers 22FR, 22FL, 22RR and 22RL so as to adjust their damping forces, in order to compensate for the adjustment delays that the stabilizer devices 14 and 16 have relative to the roll speed of the roll that occurs on the vehicle 10. In other words, the roll control apparatus 100 controls the shock absorbers 22FR, 22FL, 22RR and 22RL so that anti-roll moments as mentioned above are produced, on the condition that the roll speed of the roll that occurs on the vehicle 10 is such a degree of speed as to cause following response delays of the stabilizer devices 14 and 16.

[0108] Besides, from a viewpoint of the signals that are supplied to the stabilizer devices 14 and 16, and the shock absorbers 22FR, 22FL, 22RR and 22RL, the roll control apparatus 100 controls the shock absorbers 22FR, 22FL, 22RR and 22RL by changing the target control step of the shock absorbers so that the anti-roll moments that suppress the roll moments that occur on the vehicle 10 becomes larger in the case where the target rotation angles φft and φrt are large. [0109] Besides, from a viewpoint of the so-called active suspension, the AVS

ECU 32 adjusts the damping force of the shock absorbers 22FR, 22FL, 22RR and 22RL by controlling the shock absorbers so as to produce anti-roll moments that suppress the roll moments that occur on the vehicle 10, according to the target anti-roll moments Mat, and the actual anti-roll moments produced by the stabilizer devices 14 and 16. [0110] In the embodiment, in particular, a following response delay anti-roll moment is calculated as a difference value between the target anti-roll moment Mat and the actual anti-roll moment. Therefore, the greater the difference value (i.e., the greater the roll moment that occurs on the vehicle 10, or the greater the target rotation angles φft and φrt), the greater the anti-roll moments produced by the shock absorbers 22FR, 22FL, 22RR and 22RL (i.e., the anti-roll moments produced by the so-called active suspensions) become.

[0111] Therefore, it is possible to suppress the roll moment that occurs on the vehicle 10 appropriately even in the case where the roll speed is relatively fast and therefore a following response delay occurs while the ride quality of the vehicle 10 is regarded as important.

[0112] Incidentally, the "stabilizer ECU 31" and the "AVS ECU 32" in accordance with the embodiment are examples of "target specific determination means",

"detection means", and "adjustment delay specific determination means" in accordance with the invention. Besides, the "control step (of the shock absorber)" is an example of a "stroke characteristic" in accordance with the invention.

[0113] Incidentally, in the case where the control step of each of the shock absorbers 22FR, 22FL, 22RR and 22RL is stepwise (i.e., discontinuous), it suffices that the control step that provides a value of damping force that is the closest to the target damping force is set as a target control step.

[0114] The roll control apparatus 100 in accordance with the embodiment, as described above, executes the feedback control of controlling the shock absorbers 22FR, 22FL, 22RR and 22RL so as to compensate for the following response delay anti-roll moments that are difference values between the target anti-roll moments of the stabilizer devices 14 and 16 and the actual anti-roll moments thereof. However, the control is not limited to a feedback control, but may also be a feed-forward control, or may also be a control that combines a feedback control and a feed-forward control.

[0115] In the case where a feed-forward control is adopted, a concrete example of the control may be a control in which the roll control apparatus 100 sets, as following response delay anti-roll moments, difference values between the target anti-roll moments of the stabilizer devices 14 and 16 and allowable anti-roll moments of the stabilizer devices 14 and 16, respectively, and controls the shock absorbers 22FR, 22FL, 22RR and 22RL so as to compensate for the following response delay anti-roll moments. [0116] Besides, although the roll control apparatus 100 in accordance with the embodiment controls the stabilizer devices 14 and 16 according to the anti-roll moments as described above, the stabilizer devices 14 and 16 may also be controlled according to, for example, the roll rate, the roll speed, the roll rigidity, the roll angle, etc., or according to a roll control quantity as a concept that encompasses the roll rate and the like, instead of or in addition to the anti-roll moment.

[0117] Incidentally, the compensation of the following response delay anti-roll moments caused by the shock absorbers 22FR, 22FL, 22RR and 22RL (i.e., by the active suspensions) may be executed by a coordinated control of the front wheel-side shock absorbers 22FR and 22FL and the rear wheel-side shock absorbers 22RR and 22RL, or may also be executed by controlling the shock absorbers 22FR and 22FL on the front wheel side and the shock absorbers 22RR and 22RL of the rear wheel side independently of each other.

[0118] In the case where the shock absorbers 22FR and 22FL on the front wheel side and the shock absorbers 22RR and 22RL on the rear wheel side are controlled independently of each other, the shock absorbers 22FR and 22FL on the front wheel side and the shock absorbers 22RR and 22RL on the rear wheel side may be controlled according to the characteristics of the stabilizer devices 14 and 16, respectively. Concretely, for example, the timing of controlling shock absorbers (i.e., active suspensions) may be set earlier the lower the characteristic of the stabilizer device is. This construction makes it possible to appropriately suppress the roll moment that occurs on the vehicle even in the case where the response of the stabilizer devices is relatively low and the characteristic of the stabilizer device is relatively low. That is, the characteristics of the stabilizer devices can be appropriately compensated for.

[0119] Next, a modification of the roll control apparatus 100 in accordance with the embodiment will be described with reference to the flowchart shown in FIG 5.

[0120] In FIG 5, the stabilizer ECU 31, after the foregoing process of step S 104

(see FIG 3), determines whether or not the target anti-roll moment Matf of the front wheels is greater than a maximum anti-roll moment Matfmax of the stabilizer device 14 (step S311). Incidentally, the maximum anti-roll moment Matfmax means the anti-roll moment occurring when the stabilizer device 14 is operated at its maximum performance.

[0121] If it is determined that the target anti-roll moment Matf is greater than the maximum anti-roll moment Matfmax (YES in step S311), the stabilizer ECU 31 corrects the value of the target anti-roll moment Matf to the value of the maximum anti-roll moment Matfmax, and calculates a difference value between the pre-correction target anti-roll moment Matf and the maximum anti-roll moment Matfmax, as an excess anti-roll moment of the front wheel (step S312). Subsequently, the stabilizer ECU 31 sends a signal that shows the excess anti-roll moment of the front wheels to the AVS ECU 32 (step S313), and then executes the process of step S314 described later. [0122] On the other hand, if it is determined in the process of step S311 that the target anti-roll moment Matf is not greater than the maximum anti-roll moment Matfmax (NO in step S311), the stabilizer ECU 31 executes the process of the step S314 described later.

[0123] The AVS ECU 32 receives the signal from the stabilizer ECU 31 which shows the excess anti-roll moment of the front wheels (step S321), and then computes target damping forces of the front wheels on the basis of the excess anti-roll moment (step S322). Concretely, for example, the AVS ECU 32 computes a (the front-wheel excess anti-roll moment/the roll rate) as a damping coefficient, and computes target increase-decrease damping forces of the front wheels. Furthermore, the AVS ECU 32 computes stroke speeds of the front wheels FR and FL from the differential values Xdi of the strokes Xi detected by the stroke sensor 45, and computes target control steps of the shock absorbers 22FR and 22FL on the basis of the target damping forces and the stroke speeds of the front wheels.

[0124] Incidentally, the processes of the steps S321 and S322 of the AVS ECU 32 are not executed in the case where a result of the determination process of step S311 of the stabilizer ECU 31 is "NO".

[0125] The stabilizer ECU 31 determines whether or not the target anti-roll moment Matr of the rear wheels is greater than a maximum anti-roll moment Matrmax of the stabilizer device 16 (step S314), after it is determined in the process of step S311 that the target anti-roll moment Matf is not greater than the maximum anti-roll moment Matfmax (NO in step S311), or after the process of step S313 is executed. Incidentally, the maximum anti-roll moment Matrmax means the anti-roll moment that occurs when the stabilizer device 16 is operated at its maximum performance. [0126] If it is determined that the target anti-roll moment Matr is greater than the maximum anti-roll moment Matrmax (YES in step S314), the stabilizer ECU 31 corrects the value of the target anti-roll moment Matr to the value of the maximum anti-roll moment Matrmax, and computes a difference value between the pre-correction target anti-roll moment Matr and the maximum anti-roll moment Matrmax, as an excess anti-roll moment of the rear wheels (step S315). Subsequently, the stabilizer ECU 31 sends a signal that shows the excess anti-roll moment of the rear wheels to the AVS ECU 32 (step S316), and then executes the foregoing process of step S105 (see FIG 3).

[0127] On the other hand, if it is determined in the process of step S314 that the target anti-roll moment Matr is not greater than the maximum anti-roll moment Matrmax (NO in step S314), the stabilizer ECU 31 executes the process of step S105.

[0128] The AVS ECU 32 receives the signal that shows the excess anti-roll moment of the rear wheels from the stabilizer ECU 31 (step S323), and computes target damping forces of the rear wheels on the basis of the excess anti-roll moment (step S324). [0129] Incidentally, the process of steps S323 and S324 of the AVS ECU 32 are not executed in the case where a result of the determination process of step S314 of the stabilizer ECU 31 is "NO".

[0130] Next, the AVS ECU 32 controls the shock absorbers 22FR, 22FL, 22RR and 22RL on the basis of the target damping forces of the front wheels and the target damping forces of the rear wheels (step S325). More concretely, the AVS ECU 32 controls the shock absorbers 22FR, 22FL, 22RR and 22RL so that the control step of each of the shock absorbers 22FR, 22FL, 22RR and 22RL is caused to be at a corresponding one of the target damping forces of the front wheels and the target damping forces of the rear wheels.

[0131] Therefore, even in the case where the anti-roll moments generated by the stabilizer devices 14 and 16 are short of the target anti-roll moments, the shortfalls in the anti-roll moment can be compensated for by changing the damping forces that are generated by the shock absorbers 22FR, 22FL, 22RR and 22RL. As a result, even in the case where the roll moment is relatively great so that the target anti-roll moment and the actual anti-roll moment are likely to deviate from each other, discomfort in the roll direction is not caused to a driver or the like of the vehicle 10. Thus, this modification is very advantageous from a practical standpoint.

[0132] Incidentally, the process of step S325 of the AVS ECU 32 is not executed in the case where a result of the determination processes of step S311 and step S314 of the stabilizer ECU 31 are both "NO".

[0133] Incidentally, although in FIG 5, the process of steps S311 to S313 is executed prior to the process of steps S314 to S316, the process of steps S314 to S316 may also be executed prior to the process of steps S311 to S313, or the process of steps S311 to S313 and the process of steps S314 to S316 may also be executed in parallel.

[0134] Incidentally, the invention is not limited to the foregoing embodiments, the examples, or the like, but can be modified appropriately within a range that does not contradict the gist of the invention that can be interpreted from the entire specification and the appended claims, and roll control apparatuses for a vehicle that include such modifications or the like are also within the technical scope of the invention.

Claims

1. A vehicle roll control apparatus characterized by comprising: a first device that adjusts roll rigidity of a vehicle; a second device that adjusts stroke characteristic between wheels of the vehicle and a cabin of the vehicle; and control means for controlling the first device and the second device so as to suppress roll moment that occurs on the vehicle, wherein the control means controls the second device so as to adjust the stroke characteristic, in order to compensate for an adjustment delay made by the first device relative to roll speed of the roll that occurs on the vehicle.

2. The vehicle roll control apparatus according to claim 1, wherein the control means includes: target specific determination means for specifically determining a target anti-roll moment for suppressing the roll moment; detection means for detecting anti-roll moment that is produced by the first device; and adjustment delay specific determination means for specifically determining a difference between the specifically determined target anti-roll moment and the detected anti-roll moment, as the adjustment delay made by the first device.

3. A vehicle roll control apparatus characterized by comprising: a variable stabilizer that adjusts roll rigidity of a vehicle; a variable suspension that adjusts damping force of a suspension mechanism of the vehicle; and control means for controlling the variable stabilizer and the variable suspension so as to suppress roll force that occurs on the vehicle, wherein the control means controls the variable suspension so that anti-roll force becomes large, when roll speed of the roll that occurs on the vehicle is fast.

4. A vehicle roll control apparatus characterized by comprising: a variable stabilizer that adjusts roll rigidity of a vehicle; a variable suspension that adjusts damping force of a suspension mechanism of the vehicle; and control means for controlling the variable stabilizer and the variable suspension according to a first control command value for controlling the variable stabilizer, and a second control command value for controlling the variable suspension, wherein when the first control command value is large, the control means controls the variable suspension by changing the second control command value so that anti-roll force that suppresses the roll force that occurs on the vehicle becomes large.

5. A vehicle roll control apparatus characterized by comprising: an active stabilizer that adjusts roll rigidity of a vehicle so that a roll characteristic approaches a target roll characteristic value; and an active suspension that adjusts stroke characteristic between wheels of the vehicle and a cabin of the vehicle, wherein the active suspension adjusts the stroke characteristic so as to produce anti-roll force that suppresses roll force that occurs on the vehicle, according to the target roll characteristic value, and the roll characteristic value given by the active stabilizer.