Electrically powered suspension system

Included are an electromagnetic actuator which generates drive forces for a damping operation and a telescopic operation; an information acquirer which acquires information about the drive forces of, and control mode selection information about, the electromagnetic actuator; a drive force arithmetic part which sets a predetermined control mode based on the control mode selection information about the electromagnetic actuator, and sets a target damping force and a target telescopic force of the electromagnetic actuator based on setting information about the control mode; and a drive controller which controls drive of the electromagnetic actuator using a target drive force based on the target damping and telescopic forces set by the drive force arithmetic part. The drive force arithmetic part performs an operation of switching a setting of the predetermined control mode from one to another while a driving force of the electromagnetic actuator is within a predetermined force range.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims priority from the Japanese Patent Application No. 2019-61141, filed on Mar. 27, 2019, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrically powered suspension system which includes an electromagnetic actuator provided between a vehicle body and a wheel of a vehicle, and configured to generate drive forces for a damping operation and a telescopic operation.

2. Description of the Related Art

An electrically powered suspension system has been known which includes an electromagnetic actuator provided between a vehicle body and a wheel of a vehicle, and configured to generate drive forces for a damping operation and a telescopic operation (see, for example, Japanese Patent Application Publication No. 2010-132222, hereinafter referred to as “Patent Document 1”). The electromagnetic actuator includes an electric motor and a ball screw mechanism. The electromagnetic actuator operates to generate the drive forces for the damping operation and the telescopic operation by converting the rotary motion of the electric motor into the linear motion of the ball screw mechanism.

In this respect, the drive force for the damping operation means a damping force. The damping force is a force in a direction opposite to a direction of a stroke velocity of the electromagnetic actuator. Meanwhile, the drive force for the telescopic operation means a telescopic force. The telescopic force is a force which is generated regardless of the direction of the stroke velocity.

The electrically powered suspension system disclosed in Patent Document 1 includes a velocity-damping force map which defines a correspondence relationship between the stroke velocity and the damping force of the electromagnetic actuator. The electrically powered suspension system is designed to enhance the ride quality and driving stability of the vehicle by: calculating a target damping force corresponding to the stroke velocity of the electromagnetic actuator based on the stroke velocity and the velocity-damping force map; and controlling the drive of the electromagnetic actuator using a target drive force based on the calculated target damping force.

SUMMARY OF THE INVENTION

The electrically powered suspension system disclosed in Patent Document 1, however, involves a risk that when a switch is made from one control mode setting to another, a sudden change occurs in the drive force of the electromagnetic actuator and causes strange noise as well as disturbance of the vehicle behavior.

The present invention has been made with the above situation taken into consideration. An object thereof is to provide an electrically powered suspension system which is capable of preventing the occurrence of the strange noise and the disturbance of the vehicle behavior even when a switch is made from one control mode to another.

For the purpose of achieving the above object, an invention based on a first aspect has a major feature as follows. The invention includes: an electromagnetic actuator which is provided between a vehicle body and a wheel of a vehicle, and which generates a drive force for a damping operation; an information acquirer which acquires information about the drive force of, and control mode selection information about, the electromagnetic actuator; a setter which sets a predetermined control mode based on the control mode selection information about the electromagnetic actuator acquired by the information acquirer, and a target damping force serving as a target value of the damping operation of the electromagnetic actuator based on setting information about the control mode; and a drive controller which controls drive of the electromagnetic actuator using a target drive force based on the target damping force set by the setter. The setter performs an operation of setting the predetermined control mode while a drive force of the electromagnetic actuator acquired by the information acquirer is within a predetermined force range.

The present invention can prevent the occurrence of the strange noise and the disturbance of the vehicle behavior even when a switch is made from one control mode to another.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An electrically powered suspension system according to an embodiment of the present invention will be hereinafter described in detail with reference to the accompanying drawings depending on the necessity.

It should be noted that in the following diagrams, members having common functions will be denoted by common reference signs. In addition, sizes and shapes of members are schematically illustrated with deformation or exaggeration for the sake of explanatory convenience.

[A Basic Configuration Common Among of Electrically Powered Suspension Systems11According to Embodiments of the Present Invention]

To begin with, referring toFIGS.1and2, descriptions will be provided for the basic configuration common among the electrically powered suspension systems11according to the embodiments of the present invention.

FIG.1is a diagram of the overall configuration common among the electrically powered suspension systems11according to the embodiments of the present invention.FIG.2is a partial cross-sectional diagram of an electromagnetic actuator13constituting apart of each electrically powered suspension systems11.

As illustrated inFIG.1, the electrically powered suspension system11according to each embodiment of the present invention includes: multiple electromagnetic actuators13provided to the respective wheels of a vehicle10; and a single electronic control unit (hereinafter referred to as an “ECU”)15. The multiple electromagnetic actuators13and the ECU15are connected to one another with: electric power supply lines14(see solid lines inFIG.1) which supply drive control power from the ECU15to the multiple electromagnetic actuators13; and signal lines16(see broken lines inFIG.1) which send rotation angle signals of electric motors31(seeFIG.2) from the multiple electromagnetic actuators13to the ECU15, respectively.

In the embodiment, four electromagnetic actuators13in total are provided to the respective wheels: including front wheels (a left front wheel and a right front wheel); and rear wheels (a left rear wheel and a right rear wheel). Drives of the electromagnetic actuators13provided to the wheels are controlled independently of one another in response to the telescopic operations of the wheels, respectively.

In the embodiment of the present invention, the multiple electromagnetic actuators13include a common configuration unless otherwise indicated specifically. Descriptions of the multiple electromagnetic actuators13, therefore, will be provided by describing the configuration of one electromagnetic actuator13.

As illustrated inFIG.2, the electromagnetic actuator13includes a base housing17, an outer tube19, ball bearings21, a ball screw shaft23, multiple balls25, a nut27and an inner tube29.

The base housing17supports a base end side of the ball screw shaft23with the ball bearings21in between in a way that enables the ball screw shaft23to rotate about its axis. The outer tube19is provided to the base housing17, and contains a ball screw mechanism18including the ball screw shaft23, the multiple balls25and the nut27. The multiple balls25roll along a screw groove in the ball screw shaft23. The nut27engages with the ball screw shaft23with the multiple balls25in between, and converts the rotational motion to the linear motion of the ball screw shaft23. The inner tube29linked to the nut27displaces integrally with the nut27in an axial direction of the outer tube19.

As illustrated inFIG.2, for the purpose of transmitting a rotary drive force to the ball screw shaft23, the electromagnetic actuator13includes an electric motor31, a pair of pulleys33and a belt member35. The electric motor31is provided to the base housing17in parallel to the outer tube19. The pulleys33are respectively attached to a motor shaft31aof the electric motor31and the ball screw shaft23. The belt member35which transmits the rotary drive force of the electric motor31to the ball screw shaft23is suspended between the pair of pulleys33.

The electric motor31is provided with a resolver37which detects the rotation angle signal of the electric motor31. The rotation angle signal of the electric motor31which is detected by the resolver37is sent to the ECU15through the signal line16. The rotary drive of the electric motor31is controlled in response to the drive control power which the ECU15supplies to a corresponding one of the multiple electromagnetic actuators13through a corresponding one of the electric power supply lines14.

It should be noted that in the embodiment, the axial-direction dimension of the of the electromagnetic actuator13is made shorter than otherwise by employing a layout in which the motor shaft31aof the electric motor31and the ball screw shaft23are linked together by being arranged substantially in parallel with each other, as illustrated inFIG.2. A layout, however, may be employed in which the motor shaft31aof the electric motor31and the ball screw shaft23are linked together by being arranged coaxially.

In the electromagnetic actuator13according to the embodiment, a link part39is provided to a lower end portion of the base housing17, as illustrated inFIG.2. The link part39is linked and fixed to a spring lower member (a wheel-side lower arm, knuckle or the like), although not illustrated. Meanwhile, an upper end part29aof the inner tube29is linked and fixed to a sprung member (a vehicle body-side strut tower part or the like), although not illustrated.

In short, the electromagnetic actuator13is installed in parallel with the spring member provided between the vehicle body and the wheel of the vehicle10, although not illustrated. The sprung member is provided with a sprung acceleration sensor40(seeFIG.3) which detects the (sprung) acceleration of the vehicle body in a stroke direction of the electromagnetic actuator13.

The above-configured electromagnetic actuator13works as follows. Let us consider, for example, a case where a thrust related to upward vibration is inputted from the wheel side of the vehicle10into the link part39. In this case, the inner tube29and the nut27are going to integrally descend relative to the outer tube19to which the thrust related to the upward vibration is applied. Thus, the ball screw shaft23is going to rotate in a direction corresponding to the descent of the nut27. At this moment, the electric motor31generates the rotary drive force in a direction in which the rotary drive force obstructs the descent of the nut27. The rotary drive force of the electric motor31is transmitted to the ball screw shaft23through the belt member35.

In this way, the reaction force (damping force) against the thrust related to the upward vibration works on the ball screw shaft23. This damps the damping force which is going to be transmitted from the wheel side to the vehicle body side.

[An Internal Configuration of the ECU15]

Next, referring toFIGS.3,4and5A to5C, descriptions will be provided for an interior portion and a peripheral portion of the ECU15included in the electrically powered suspension system11according to the embodiment of the present invention.FIG.3is a configuration diagram of the interior portion and the peripheral portion of the ECU15included in the electrically powered suspension system11according to the embodiment of the present invention.FIG.4is a diagram conceptually illustrating the interior portion of the ECU15included in the electrically powered suspension system11.FIG.5Ais an explanatory diagram of a first damping force map52afor a comfort mode which represents a relationship between a first damping force and a stroke velocity SV.FIG.5Bis an explanatory diagram of a second damping force map52bfor a normal mode which represents a relationship between a second damping force and the stroke velocity SV.FIG.5Cis an explanatory diagram of a third damping force map52cfor a sport mode which represents a relationship between a third damping force and the stroke velocity SV.

The ECU15includes a microcomputer which performs various arithmetic processes. The ECU15has a drive control function of generating drive forces for a damping operation and a telescopic operation by controlling drives of the multiple electromagnetic actuators13based on the rotation angle signals of the electric motors31and the like, which are detected by the resolvers37.

For the purpose of realizing the drive control function, the ECU15includes an information acquirer43, a drive force arithmetic part47and a drive controller49, as illustrated inFIG.3.

The information acquirer43acquires information about the stroke velocity SV by: acquiring the rotation angle signal of the electric motor31, detected by the resolver37, as time-series information about a stroke position; and differentiating the time-series information about the stroke position with respect to time, as illustrated inFIG.3.

In addition, the information acquirer43acquires information about a sprung velocity BV: acquiring time-series information about a sprung acceleration detected by the sprung acceleration sensor40; and differentiating the time-series information about the sprung acceleration with respect to time, as illustrated inFIG.3.

Furthermore, the information acquirer43acquires information about a vehicle speed detected by a vehicle speed sensor41, information about a yaw rate detected by a yaw rate sensor42, a control mode selection signal to be used to select one control mode from multiple damping force control modes and multiple telescopic force control modes, and information about an actual drive force of the electromagnetic actuator13, as illustrated inFIG.3.

After acquired by the information acquirer43, the information about the stroke velocity SV, the information about the sprung velocity BV, the control mode selection signal and the information about the actual drive force of the electromagnetic actuator13are sent to the drive force arithmetic part47.

As illustrated inFIG.4, the drive force arithmetic part47includes a damping force setter51, a telescopic force setter53, a drive force determination part55and an adder57. The drive force arithmetic part47corresponds to a “setter” of the present invention.

The drive force arithmetic part47basically has a function of: setting a target damping force serving as a target value of the damping operation of the electromagnetic actuator13, and a target telescopic force serving as a target value of the telescopic operation of the electromagnetic actuator13; and acquiring driving forces for the damping operation and the telescopic operation of the electromagnetic actuator13for the purpose of realizing the thus-set target damping and telescopic forces.

To put it in detail, the drive force arithmetic part47sets a damping force control mode and a telescopic force control mode of the electromagnetic actuator13based on the control selection information about the electromagnetic actuator13. The control selection information about the electromagnetic actuator13is information to be used to selectively instruct control modes (one of the damping force control modes and one of the telescopic force control modes) of the electromagnetic actuator13based on the driver's instruction manipulation.

Examples of the control modes (the damping force control modes and the telescopic force control modes) of the electromagnetic actuator13includes: the comfort mode in which a comfortable ride quality is offered with suppressed vibrations inside a vehicle compartment; the normal mode in which a standard ride quality is offered; and the sport mode in which driving stability of the vehicle10is prioritized over the ride quality.

The drive force arithmetic part47sets the target damping force serving as the target value of the damping operation of the electromagnetic actuator13and the target telescopic force serving as the target value of the telescopic operation of the electromagnetic actuator13based on control mode setting information (for example, information about the setting of the comfort mode as one of the control mode).

Specifically, as illustrated inFIG.4, the drive force arithmetic part47includes a damping force setter51which sets one of the damping forces corresponding respectively to the comfort mode, the normal mode and the sport mode serving as the control modes. The damping force setter51includes first to third damping force maps52a,52b,52c.

As illustrated inFIGS.5A to5C, for the control modes, respectively, the first to third damping force maps52a,52b,52cstore values of first to third damping forces which change in association with changes in the stroke velocity SV. Incidentally, the values of the first to third damping forces are actually stored as target values of a damping force control current.

First damping force characteristics related to the comfort mode are associated with the first damping force map52a. Second damping force characteristics related to the normal mode are associated with the second damping force map52b. Third damping force characteristics related to the sport mode are associated with the third damping force map52c.

The first damping force characteristics related to the comfort mode include a first linear velocity range SV1in which the first damping force changes substantially linearly in response to changes in the stroke velocity SV, as illustrated inFIG.5A. The first damping force characteristics in the first linear velocity range SV1include a characteristic in which: the first damping force in a direction to the contracted side becomes substantially linearly larger as the stroke velocity SV becomes larger in a direction to the stretched side; and the first damping force in the direction to the stretched side becomes substantially linearly larger as the stroke velocity SV becomes larger in the direction to the contracted side. Incidentally, when the stroke velocity SV is at 0, the corresponding first damping force is also at 0.

Like the first damping force characteristics, the second damping force characteristics related to the normal mode include a second linear velocity range SV2in which the second damping force changes substantially linearly in response to changes in the stroke velocity SV, as illustrated inFIG.5B. The second damping force characteristics in the second linear velocity range SV2include a characteristic in which: the second damping force in the direction to the contracted side becomes substantially linearly larger as the stroke velocity SV becomes larger in the direction to the stretched side; and the second damping force in the direction to the stretched side becomes substantially linearly larger as the stroke velocity SV becomes larger in the direction to the contracted side. Incidentally, when the stroke velocity SV is at 0, the corresponding second damping force is also at 0.

Like the first and second damping force characteristics, the third damping force characteristics related to the sport mode include a third linear velocity range SV3in which the third damping force changes substantially linearly in response to changes in the stroke velocity SV, as illustrated inFIG.5C. The third damping force characteristics in the third linear velocity range SV3include a characteristic in which: the third damping force in the direction to the contracted side becomes substantially linearly larger as the stroke velocity SV becomes larger in the direction to the stretched side; and the third damping force in the direction to the stretched side becomes substantially linearly larger as the stroke velocity SV becomes larger in the direction to the contracted side. Incidentally, when the stroke velocity SV is at 0, the corresponding third damping force is also at 0.

The inclination of the second damping force characteristics in the second linear velocity range SV2(seeFIG.5B) is set steeper than that of the first damping force characteristics in the first linear velocity range SV1(seeFIG.5A).

Similarly, the inclination of the third damping force characteristics in the third linear velocity range SV3(seeFIG.5C) is set steeper than that of the second damping force characteristics in the second linear velocity range SV2(seeFIG.5B).

A velocity change width in the second linear velocity range SV2(seeFIG.5B) is set narrower than that in the first linear velocity range SV1(seeFIG.5A).

Similarly, a velocity change width in the third linear velocity range SV3(seeFIG.5C) is set narrower than that in the second linear velocity range SV2(seeFIG.5B).

The damping force setter51included in the drive force arithmetic part47sets the value of the damping force corresponding to the stroke velocity SV at the moment as the target damping force, by use of the damping force map52based on the control mode setting information by selecting one from the first to third damping force maps52a,52b,52cwhich are map variations of the damping force map52.

Meanwhile, as illustrated inFIG.4, the drive force arithmetic part47includes the telescopic force setter53which sets one of the telescopic forces corresponding respectively to the comfort mode, the normal mode and the sport mode serving as the control modes. The telescopic force setter53includes first to third telescopic force maps54a,54b,54c.

For the respective control modes, respectively, the first to third telescopic force maps54a,54b,54cstore the values of the target telescopic forces which change in association with changes in the sprung acceleration BV. Incidentally, the values of the target telescopic forces are actually stored as target values of a telescopic force control current.

First telescopic force characteristics related to the comfort mode are associated with the first telescopic force map54a. Second telescopic force characteristics related to the normal mode are associated with the second telescopic force map54b. Third telescopic force characteristics related to the sport mode are associated with the third telescopic force map54c. Incidentally, a relationship between the first to third telescopic force characteristics and the present invention is weak, and their attachment is omitted.

The telescopic force setter53included in the drive force arithmetic part47sets the value of the telescopic force corresponding to the sprung velocity BV at the moment as the target telescopic force, by use of a telescopic force map54based on the control mode setting information by selecting one from the first to third telescopic force maps54a,54b,54cwhich are map variations54a,54b,54cof the telescopic force map54.

A predetermined force range FA is set in the drive force determination part55included in the drive force arithmetic part47. For the purpose of preventing the drive force of the electromagnetic actuator13from suddenly changing when a switch is made from one control mode to another, an appropriate range acquired through an experiment, a simulation or the like may be set as the predetermined force range FA.

The drive force determination part55performs a drive force determination on whether the actual drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43falls within the predetermined force range FA.

In a case where as a result of the drive force determination, the drive force determination part55determines that the actual drive force Fdr of the electromagnetic actuator13falls within the predetermined force range FA, the drive force determination part55sends a setting operation permission signal for permitting the setting operation based on the control mode setting information, to the damping force setter51and the telescopic force setter53.

In short, the drive force arithmetic part47performs the setting switch operation based on the control mode setting information while the actual drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43is within the predetermined force range FA.

This prevents a situation which would otherwise cause strange noise and behavior disturbance of the vehicle due to a sudden change in the drive force of the electromagnetic actuator13when the switch is made from one control mode to another.

As illustrated inFIG.4, the adder57included in the drive force arithmetic part47acquires the target drive force by summing up the target damping force set by the damping force setter51and the target telescopic force set by the telescopic force setter53, and acquires a drive control signal for realizing the target drive force through an arithmetic operation. The drive control signal as the result of the arithmetic operation performed by the drive force arithmetic part47is sent to the drive controller49.

Based on the drive control signal sent from the drive force arithmetic part47, the drive controller49controls the drives of the multiple electromagnetic actuators13independently of one another by supplying the drive control powers to the electric motors31provided to the multiple electromagnetic actuators13, respectively.

It should be noted that, for example, an inverter control circuit may be appropriately used to generate drive control power to be supplied to the electric motor31.

[How the Electrically Powered Suspension Systems11According to the Embodiments of the Present Invention Works]

Next, referring toFIG.6, descriptions will be provided for how the electrically powered suspension system11according to each embodiment of the present invention works.FIG.6is a flowchart diagram used to explain how the electrically powered suspension system11according to the embodiment of the present invention works.

In step S11(a stroke velocity acquiring step) illustrated inFIG.6, the information acquirer43of the ECU15acquires the information about the stroke velocity SV by: acquiring the rotation angle signal of the electric motor31, detected by the resolver37, as the time-series information about the stroke position; and differentiating the time-series information about the stroke position with respect to time. The thus-acquired information about the stroke velocity SV is sent to the drive force arithmetic part47.

In step S12(a sprung velocity acquiring step), the information acquirer43of the ECU15acquires the information about the sprung velocity BV by: acquiring the time-series information about the sprung acceleration detected by the sprung acceleration sensor40; and differentiating the time-series information about the sprung acceleration with respect to time. The thus-acquired information about the sprung velocity BV is sent to the drive force arithmetic part47.

In step S13(a control mode and actual drive force acquiring step), the information acquirer43of the ECU15acquires the control mode selection signal representing the information about the damping force control mode selection and the telescopic force control mode selection, as well as the information about the actual drive force of the electromagnetic actuator13.

In step S14, the drive force determination part55included in the drive force arithmetic part47of the ECU15performs the drive force determination on whether the actual drive force Fdr of the electromagnetic actuator13acquired in step S13falls within the predetermined force range FA (whether |Fdr|<FA).

If the result of the drive force determination performed in step S14is that the actual drive force Fdr of the electromagnetic actuator13falls within the predetermined force range FA (if Yes in step S14), the ECU15makes the process flow proceed to the next step S15. In addition, the drive force determination part55included in the drive force arithmetic part47of the ECU15sends the setting operation permission signal for permitting the setting operation based on the control mode setting information, to the damping force setter51and the telescopic force setter53.

On the other hand, if the result of the drive force determination performed in step S14is that the actual drive force Fdr of the electromagnetic actuator13does not fall within the predetermined force range FA (if No in step S14), the ECU15makes the process flow jump to step S16.

If the result of the drive force determination performed in step S14is that the actual drive force Fdr of the electromagnetic actuator13falls within the predetermined force range FA, the drive force arithmetic part47of the ECU15sets the target damping force and the target telescopic force by reflecting the latest control mode setting in step S15.

In other words, upon receipt of the setting operation permission signal sent from the drive force determination part55, the damping force setter51and the telescopic force setter53included in the drive force arithmetic part47of the ECU15perform the setting switch operation based on the control mode setting information while the actual drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43is within the predetermined force range FA.

In other words, the damping force setter51included in the drive force arithmetic part47of the ECU15sets the value of the damping force corresponding to the stroke velocity SV at the moment as the target damping force, by use of the damping force map52based on the setting information about the control mode selection signal acquired in step S13by selecting one from the first to third damping force maps52a,52b,52cwhich are the map variations of the damping force map52.

In addition, the telescopic force setter53included in the drive force arithmetic part47of the ECU15sets the value of the telescopic force corresponding to the sprung velocity BV at the moment as the target telescopic force, by use of the telescopic force map54based on the control mode setting information about the control mode selection signal acquired in step S13by selecting one from the first to third telescopic force maps54a,54b,54cwhich are the map variations54a,54b,54cof the telescopic force map54.

If the result of the drive force determination performed in step S14is that the actual drive force Fdr of the electromagnetic actuator13does not fall within the predetermined force range FA, the drive force arithmetic part47of the ECU15sets the target damping force and the target telescopic force by maintaining the established control mode setting in step S16.

In step17(a drive force arithmetic process step), the adder57including in the drive force arithmetic part47of the ECU15acquires the target drive force by summing up the target damping force set in step S15or S16by the damping force setter51and the target telescopic force set in step S15or S16by the telescopic force setter53, and acquires the drive control signal for realizing the target drive force through an arithmetic operation.

In step S18, the drive controller49of the ECU15controls the drives of the multiple electromagnetic actuators13by supplying the drive control powers to the electric motors31provided to the electromagnetic actuators13based on the drive control signals acquired through the arithmetic process in step S17, respectively.

[An Internal Configuration of an ECU15Included in an Electrically Powered Suspension System11According to a Modification of the Embodiment of the Present Invention]

Next, referring toFIG.7, descriptions will be provided for the internal configuration of the ECU15included in the electrically powered suspension system11according to the modification of the embodiment of the present invention.FIG.7is a diagram conceptually illustrating the interior portion of the ECU15included in the electrically powered suspension system11according to the modification of the embodiment of the present invention.

The configuration of the electrically powered suspension system11according to the embodiment of the present invention which is illustrated inFIG.4and the configuration of the electrically powered suspension system11according to the modification of the embodiment of the present invention which is illustrated inFIG.7are common in many parts.

The configuration of the electrically powered suspension system11according to the modification of the embodiment of the present invention, therefore, will be described by explaining mainly what makes the electrically powered suspension system11according to the modification of the embodiment of the present invention different from the electrically powered suspension system11according to the embodiment of the present invention.

The electrically powered suspension system11according to the modification of the embodiment of the present invention is different from the electrically powered suspension system11according to the embodiment of the present invention in that: the information acquirer43acquires further information about the vehicle speed and information about the condition of a drive force generator (not illustrated) which generates the drive force of the vehicle10; and the information about the vehicle speed and the information about the condition of the drive force generator which are acquired by the information acquirer43are inputted into the drive force determination part55included in the drive force arithmetic part47of the ECU15.

[Working and Effects of the Electrically Powered Suspension System11According to the Embodiment of the Present Invention]

The electrically powered suspension system11based on a first aspect includes: the electromagnetic actuator13which is provided between the vehicle body and the wheel of the vehicle10, and which generates the drive force for the damping operation; the information acquirer43which acquires the information about the drive force of, and the control mode selection information about, the electromagnetic actuator13; the drive force arithmetic part (setter)47which sets the predetermined control mode based on the control mode selection information about the electromagnetic actuator13acquired by the information acquirer43, and sets the target damping force serving as the target value of the damping operation of the electromagnetic actuator13based on the setting information about the control mode; and the drive controller49which controls the drive of the electromagnetic actuator13using the target drive force based on the target damping force set by the drive force arithmetic part47.

The drive force arithmetic part (setter)47performs the operation of setting the predetermined control mode while the drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43is within the predetermined force range FA.

In the electrically powered suspension system11based on the first aspect, the drive force arithmetic part47performs the operation of setting the predetermined control mode while the drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43is within the predetermined force range FA.

In this respect, the operation of setting the control mode includes not only the setting (including both the mere setting and the switch setting) of the control mode, but also the operation of setting the target damping force of the electromagnetic actuator13based on the control mode setting information (this setting operation enables the drive of the electromagnetic actuator13to be actually controlled based on the target damping force).

In addition, the period while the drive force Fdr of the electromagnetic actuator13is within the predetermined force range FA is defined as a period while no sudden change occurs in the drive force of the electromagnetic actuator13at time of switching the control mode setting from one to another even if the switch is made.

Furthermore, the performing of the operation of setting the predetermined control mode while the drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43is within the predetermined force range FA means that the performing of the operation of setting the predetermined control mode waits for the drive force Fdr of the electromagnetic actuator13to fall within the predetermined force range FA.

The electrically powered suspension system11based on the first aspect performs the operation of setting the control mode while the drive force Fdr of the electromagnetic actuator13is within the predetermined force range FA. The electrically powered suspension system11, therefore, causes no sudden change in the drive force of the electromagnetic actuator13even when switching the control mode setting from one to another. Thus, the electrically powered suspension system11can prevent the occurrence of the strange noise and the disturbance of the vehicle behavior.

The electrically powered suspension system11based on a second aspect includes: the electromagnetic actuator13which is provided between the vehicle body and the wheel of the vehicle10, and which generates the drive forces for the damping operation and the telescopic operation; the information acquirer43which acquires the information about the drive forces of, and the control mode selection information about, the electromagnetic actuator13; the drive force arithmetic part (setter)47which sets the predetermined control mode based on the control mode selection information about the electromagnetic actuator13acquired by the information acquirer43, and sets the target damping force serving as the target value of the damping operation of the electromagnetic actuator13and the target telescopic force serving as the target value of the telescopic operation of the electromagnetic actuator13, based on the setting information about the control mode; and the drive controller49which controls the drive of the electromagnetic actuator13using the target drive force based on the target damping and telescopic forces set by the drive force arithmetic part47.

The drive force arithmetic part (setter)47performs the operation of switching the setting of the predetermined control mode from one to another while the drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43is within the predetermined force range FA.

The electrically powered suspension system11based in the second aspect is different from the electrically powered suspension system11based on the first aspect in that: the former refers to the electromagnetic actuator13which generates the drive forces for the damping operation and the telescopic operation; the drive force arithmetic part (setter)47sets the target damping force and the target telescopic force; and the drive force arithmetic part (setter)47performs the operation of switching the setting of the predetermined control mode from one to another.

In other words, the electrically powered suspension system11based in the second aspect, the drive force arithmetic part47performs the operation of switching the setting of the predetermined control mode from one to another while at least one of the drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43, the target drive force, the target damping force and the target telescopic force is within the predetermined force range FA.

In this respect, the operation of switching the setting of the control mode from one to another includes not only the switching of the setting of the control mode from one to another, but also the operation of switching the setting of the target damping and telescopic forces of the electromagnetic actuator13based on the control mode setting information (this operation of switching the setting from one to another enables the drive of the electromagnetic actuator13to be actually controlled based on at least one of the target damping force and the target telescopic force).

In addition, the period while at least one of the drive force Fdr of the electromagnetic actuator13, the target drive force, the target damping force and the target telescopic force is within the predetermined force range FA is within the predetermined force range FA is defined as a period while no sudden change occurs in the drive force of the electromagnetic actuator13even when the control mode setting is switched from one to another.

The electrically powered suspension system11based on the second aspect performs the operation of switching the setting of the control mode from one to another while at least one of the drive force Fdr of the electromagnetic actuator13, the target drive force, the target damping force and the target telescopic force is within the predetermined force range FA. The electrically powered suspension system11, therefore, causes no sudden change in the drive force of the electromagnetic actuator13even when switching the control mode setting from one to another. Thus, the electrically powered suspension system11can prevent the occurrence of the strange noise and the disturbance of the vehicle behavior.

Furthermore, the electrically powered suspension system11based on a third aspect is the electrically powered suspension system11based on the second aspect in which: the information acquirer43acquires further the information about the stroke velocity SV of the electromagnetic actuator13, and the information about the sprung velocity BV; the drive force arithmetic part (setter)47sets the target damping force based on the information about the damping force control mode and the information about the stroke velocity SV acquired by the information acquirer43, and sets the target telescopic force based on the information about the telescopic force control mode and the information about the sprung velocity BV acquired by the information acquirer43, as well as performs the operation of switching the setting of the damping force control mode from one to another, and the operation of switching the setting of the telescopic force control mode, in mutually different timings.

The electrically powered suspension system11based on the third aspect can perform the operation of switching the setting of the damping force control mode from one to another, and the operation of switching the setting of the telescopic force control mode, in their respective suitable timings.

In addition, the electrically powered suspension system11based on a fourth aspect is the electrically powered suspension system11based on the second or third aspect, and may employ a configuration in which: the information acquirer43acquires further the information about the vehicle speed VS; and the drive force arithmetic part (setter)47controls the width of the force range FA based on the vehicle speed VS acquired by the information acquirer43. The electrically powered suspension system11based on the fourth aspect corresponds to the electrically powered suspension system11(seeFIG.7) according to the modification of the embodiments of the present invention.

Referring toFIG.8A, descriptions will be provided for how the electrically powered suspension system11based on the fourth aspect works.FIG.8Ais a diagram used to explain how the electrically powered suspension system11according to the modification of the embodiments of the present invention works.

In the electrically powered suspension system11based on the fourth aspect, the drive force arithmetic part47controls the width of the force range FA based on the vehicle speed VS.

Specifically, for example, noise which the vehicle10makes while running in a case where the vehicle speed VS is in a low vehicle speed range (including the stop) AR1(VS<VS1) is smaller than noise which the vehicle10makes while running in a case where the vehicle speed VS is in a middle-high vehicle speed range AR2(VS→VS1). When, therefore, the setting of the control mode is switched from one to another, higher quietness is required in the case where the vehicle speed VS is in the low vehicle speed range AR1than in the case where the vehicle speed VS is in the middle-high vehicle speed range AR2. On the other hand, noise which the vehicle10makes while running in the case where the vehicle speed VS is in the middle-high vehicle speed range AR2is larger than noise which the vehicle10makes while running in the case where the vehicle speed VS is in the low vehicle speed range AR1. For this reason, when the setting of the control mode is switched from one to another, higher convenience (the satisfaction of the need for switching the setting of the control mode quickly) over the quietness is required in the case where the vehicle speed VS is in the middle-high vehicle speed range AR2than in the case where the vehicle speed VS is in the low vehicle speed range AR1.

With this taken into consideration, in the electrically powered suspension system11based on the fourth aspect, the drive force arithmetic part47performs control to make the force range FA in the case where the vehicle speed VS is in the low vehicle speed range AR1narrower than the force range FA in the case where the vehicle speed VS is in the middle-high vehicle speed range AR2.

Incidentally, in the example illustrated inFIG.8A, the force range FA in the case where the vehicle speed VS is in the low vehicle speed range AR1is set at a fixed value FA1; the force range FA in the case where the vehicle speed VS is in a middle vehicle speed range (VS1=<VS<VS2) is set at (FA2−FA1, where FA1<FA2); and the force range FA in the case where the vehicle speed VS is in the high vehicle speed range is set at a fixed value FA2.

Thus, the operation of switching the setting of the predetermined control mode from one to another is performed while the drive force Fdr of the electromagnetic actuator13is small enough to fall within the force range FA controlled to become narrower in the case where the vehicle speed VS is in the low vehicle speed range AR1(in the case where higher quietness is required when the setting of the control mode is switched from one to another, since the noise which the vehicle10makes while running is small) than in the case where the vehicle speed VS is in the middle-high vehicle speed range AR2.

The setting of the control mode therefore can be quietly switched from one to another in the case where the vehicle speed VS is in the low vehicle speed range AR1.

On the other hand, in the electrically powered suspension system11based on the fourth aspect, the drive force arithmetic part47performs control to make the force range FA in the case where the vehicle speed VS is in the middle-high vehicle speed range AR2wider than the force range FA in the case where the vehicle speed VS is in the low vehicle speed range AR1.

Thus, the operation of switching the setting of the predetermined control mode from one to another is performed while the drive force Fdr of the electromagnetic actuator13is small enough to fall within the force range FA controlled to become wider in the case where the vehicle speed VS is in the middle-high vehicle speed range AR2(in the case where higher convenience over the quietness is required) than in the case where the vehicle speed VS is in the low vehicle speed range AR1. The setting of the control mode therefore can be more quickly switched from one to another in the case where the vehicle speed VS is in the middle-high vehicle speed range AR2than in the case where the vehicle speed VS is in the low vehicle speed range AR1. Accordingly, the convenience can be enhanced much more.

In the electrically powered suspension system11based on the fourth aspect, the drive force arithmetic part (setter)47controls the width of the force range FA based on the vehicle speed VS. It can be therefore expected that the electrically powered suspension system11based on the fourth aspect brings about the effect of quietly or quickly switching the setting of the control mode from one to another corresponding to the vehicle speed VS, in addition to the working and effects of the electrically powered suspension system11based on the second or third aspect.

Besides, the electrically powered suspension system11based on a fifth aspect is the electrically powered suspension system11based on the second or third aspect, and may employ a configuration in which: the information acquirer43acquires further the information about the condition of the drive force generator which generates the drive force of the vehicle10; and the drive force arithmetic part (setter)47controls the width of the force range FA based on the condition of the drive force generator acquired by the information acquirer43. The electrically powered suspension system11based on the fifth aspect corresponds to the electrically powered suspension system11(seeFIG.7) according to the modification of the embodiment of the present invention.

Referring toFIG.8B, descriptions will be provided for how the electrically powered suspension system11based on the fifth aspect works.FIG.8Bis a diagram used to explain how the electrically powered suspension system11according to the modification of the embodiment of the present invention works.

In the electrically powered suspension system11based on the fifth aspect, the drive force arithmetic part47controls the width of the force range FA based on the condition of the drive force generator.

Specifically, for example, in a case where the vehicle10is a hybrid vehicle, noise which the vehicle10makes while running is smaller in an area AR11(an area in which the engine speed ES is less than ES1, that is to say, ES<ES1) where the condition of the drive force generator is an EV mode (mainly on a low speed side) of generating the drive force using an electric motor than in an area AR12(an area in which the engine speed ES is equal to or greater than ES1, that is to say, ES>=ES1) where the condition of the drive force generator is an engine drive mode (mainly on a high speed side) of generating the drive force using an internal combustion engine. For this reason, when the setting of the control mode is switched from one to another, higher quietness is required in the area AR11where the condition of the drive force generator is the EV mode than in the area AR12where the condition of the drive force generator is the engine drive mode.

On the other hand, the noise which the vehicle10makes while running is larger in the area AR12where the condition of the drive force generator is the engine drive mode than in the area AR11where the condition of the drive force generator is the EV mode. For this reason, when the setting of the control mode is switched from one to another, higher convenience (the satisfaction of the need for quickly switching the setting of the control mode from one to another) over the quietness is required in the area AR12where the condition of the drive force generator is the engine drive mode than in the area AR11where the condition of the drive force generator is the EV mode.

With this taken into consideration, in the electrically powered suspension system11based on the fifth aspect, the drive force arithmetic part47performs the control to make the force range FA in the case (the area AR11) where the condition of the drive force generator is the EV mode narrower than the force range FA in the case (the area AR12) where the condition of the drive force generator is the engine drive mode.

Incidentally, in the example illustrated inFIG.8B, the force range FA in the area AR11(ES<ES1) where the condition of the drive force generator is the EV mode is set at a fixed value AF11; the force range FA in an area where the engine speed ES is not less than ES1but less than ES2within the area AR12where the condition of the drive force generator is the engine drive mode is set at (F12−FA11, where FA11<FA12); and the force range FA in an area where the engine speed ES is greater than ES2within the area AR12where the condition of the drive force generator is the engine drive mode is set at a fixed value FA12.

Thus, the operation of switching the setting of the predetermined control mode is switched while the drive force Fdr of the electromagnetic actuator13is small enough to fall within the force range FA controlled to become narrower in the case (the area AR11) where the condition of the drive force generator is the EV mode (in the case where higher quietness is required when the setting of the control mode is switched from one to another, since the noise which the vehicle10makes while running is small) than in the case (the area AR12) where the condition of the drive force generator is the engine drive mode.

The setting of the control mode therefore can be quietly switched from one to another in the case where the condition of the drive force generator is the EV mode.

On the other hand, in the electrically powered suspension system11based on the fifth aspect, the drive force arithmetic part47performs control to make the force range FA in the case (the area AR12) where the condition of the drive force generator is the engine drive mode wider than the force range FA in the case (the area AR11) where the condition of the drive force generator is the EV mode.

Thus, the operation of switching the setting of the predetermined control mode from one to another is performed while the drive force Fdr of the electromagnetic actuator13is small enough to fall within the force range FA controlled to become wider in the case (the area AR12) where the condition of the drive force generator is the engine drive mode (in the case where higher convenience over the quietness is required) than in the case (the area AR11) where the condition of the drive force generator is the EV mode.

The setting of the control mode therefore can be more quickly switched from one to another in the case (the area AR12) where the condition of the drive force generator is the engine drive mode than in the case (the area AR11) where the condition of the drive force generator is the EV mode. Accordingly, the convenience can be enhanced much more.

In the electrically powered suspension system11based on the fifth aspect, the drive force arithmetic part (setter)47controls the width of the force range FA based on the condition of the drive force generator. It can be therefore expected that the electrically powered suspension system11based on the fifth aspect brings about the effect of quietly or quickly switching the setting of the control mode from one to another corresponding to the condition of the drive force generator, in addition to the working and effects of the electrically powered suspension system11based on the second or third aspect.

OTHER EMBODIMENTS

The multiple embodiments discussed above are examples of how the present invention is embodied. These shall not be used to limitedly construe the technical scope of the present invention. This is because the present invention can be carried out in various modes without departing from the gist or main features of the present invention.

For example, the electrically powered suspension system11according to the embodiments of the present invention have been described using an example where the drive force determination part55performs the drive force determination on whether the actual drive force Fdr of the electromagnetic actuator13acquired by the information acquirer43falls within the predetermined force range FA. However, the present invention is not limited to this example.

The present invention may employ a configuration in which the drive force determination part55performs a drive force determination on whether the target drive force of the electromagnetic actuator13falls within the predetermined force range FA.

In addition, the electrically powered suspension systems11according to the embodiments of the present invention have been described using an example where if as a result of the drive force determination, the drive force determination part55determines that the actual drive force Fdr of the electromagnetic actuator13falls within the predetermined force range FA, the drive force determination part55sends the setting operation permission signal for permitting the setting operation based on the control mode setting information, to the damping force setter51and the telescopic force setter53. However, the present invention is not limited to this example.

The present invention may employ a setting operation instruction signal for instructing the setting operation, instead of the setting operation permission signal for permitting the setting operation based on the control mode setting information.

Furthermore, the electrically powered suspension systems11according to the embodiments of the present invention have been described using an example where the multiple control modes of the electromagnetic actuator13are the comfort mode, the normal mode and the sport mode. However, the present invention is not limited to this example.

Any control modes may be employed as the control modes of the electromagnetic actuator13which are used in the present invention, as long as they have a function of controlling at least one of the damping force and the telescopic force of the electromagnetic actuator13.

Moreover, the electrically powered suspension systems11according to the embodiments of the present invention have been described using an example where the four electromagnetic actuators13in total are arranged respectively in both the front wheels (the left front wheel and the right front wheel) and the rear wheels (the left rear wheel and the right rear wheel). However, the present invention is not limited to this example. The present invention may employ a configuration in which a total of two electromagnetic actuators13are arranged in either the front wheels or the rear wheels.

Finally, the electrically powered suspension systems11according to the embodiments of the present invention have been described referring to the drive controller49which controls the drives of the multiple electromagnetic actuators13independently of one another.

Specifically, the drive controller49may control the drives of the electromagnetic actuators13provided to the four wheels in a way that makes the controls in the respective wheels independent of one another.

Otherwise, the drive controller49may control the drives of the electromagnetic actuators13provided to the four wheels in a way that makes the controls in the front wheels and the controls in the rear wheels independent of each other, or in a way that makes the controls in the left wheels and the controls in the right wheels independent of each other.