Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
  • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
  • B60G17/0152—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit
  • B60G17/0157—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit non-fluid unit, e.g. electric motor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
  • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
  • B60G17/016—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input
  • B60G17/0162—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input mainly during a motion involving steering operation, e.g. cornering, overtaking
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
  • B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
  • B60G17/025—Spring characteristics, e.g. mechanical springs and mechanical adjusting means the mechanical spring being a torsion spring
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
  • B60G17/06—Characteristics of dampers, e.g. mechanical dampers
  • B60G17/08—Characteristics of fluid dampers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
  • B60G2202/30—Spring/Damper and/or actuator Units
  • B60G2202/31—Spring/Damper and/or actuator Units with the spring arranged around the damper, e.g. MacPherson strut
  • B60G2202/312—The spring being a wound spring
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
  • B60G2202/40—Type of actuator
  • B60G2202/42—Electric actuator
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/10—Acceleration; Deceleration
  • B60G2400/102—Acceleration; Deceleration vertical
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/20—Speed
  • B60G2400/204—Vehicle speed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/20—Speed
  • B60G2400/208—Speed of wheel rotation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/25—Stroke; Height; Displacement
  • B60G2400/252—Stroke; Height; Displacement vertical
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/40—Steering conditions
  • B60G2400/41—Steering angle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/40—Steering conditions
  • B60G2400/41—Steering angle
  • B60G2400/412—Steering angle of steering wheel or column
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/80—Exterior conditions
  • B60G2400/82—Ground surface
  • B60G2400/821—Uneven, rough road sensing affecting vehicle body vibration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/80—Exterior conditions
  • B60G2400/82—Ground surface
  • B60G2400/824—Travel path sensing; Track monitoring
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/90—Other conditions or factors
  • B60G2400/91—Frequency
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/90—Other conditions or factors
  • B60G2400/95—Position of vehicle body elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/90—Other conditions or factors
  • B60G2400/95—Position of vehicle body elements
  • B60G2400/954—Wheelbase
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2401/00—Indexing codes relating to the type of sensors based on the principle of their operation
  • B60G2401/17—Magnetic/Electromagnetic
  • B60G2401/176—Radio or audio sensitive means, e.g. Ultrasonic
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2500/00—Indexing codes relating to the regulated action or device
  • B60G2500/10—Damping action or damper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2500/00—Indexing codes relating to the regulated action or device
  • B60G2500/20—Spring action or springs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
  • B60G2600/02—Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
  • B60G2600/11—Feedforward signal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
  • B60G2600/17—Proportional control, i.e. gain control
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
  • B60G2800/16—Running
  • B60G2800/162—Reducing road induced vibrations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
  • B60G2800/90—System Controller type
  • B60G2800/91—Suspension Control
  • B60G2800/916—Body Vibration Control

Definitions

• the first aspect of the invention provides a suspension controller for controlling a suspension provided for a rear wheel of the vehicle, based on at least one value detected by at least one sensor which is provided in a front-wheel side portion of the vehicle and which is configured to detect a vertical behavior of the front-wheel side portion that is located on a side of a front wheel of the vehicle.
• the suspension controller includes a gain determiner configured to determine a gain, for controlling the suspension based on the determined gain.
• each of the at least one sensor is configured to detect the condition of the detected portion (e.g., condition of the projections and recesses on the detected portion) of the road surface, and may be provided by a sensor utilizing supersonic wave, for example.
• the vertical vibration can be satisfactorily suppressed by controlling the suspension based on the condition of the road surface detected by the at least one sensor. If the preview control were carried out when the wheel does not pass over the detected portion, the vertical vibration could not be satisfactorily suppressed or the ride comfort could be made even worse rather than being made better.
• the overlap ratio may be a value that is obtained by dividing a difference between the tire width and path difference, by the tire width.
• the path-basis overlap -amount obtaining portion includes a turning-radius obtaining portion configured to obtain the path of each of the front and rear wheels as a turning radius of each of the front and rear wheels upon turning of the vehicle.
• the vertical force generator generates the vertical force whose amount is dependent on the equalized torque and moment to the elastic member (, provided that the torsional stress and the bending strength concurrently reach an allowable stress).
• the gain may be set to a value larger when the detected portion is located in vicinity of a widthwise center of the portion of the road surface over which the tire passes, than when the detected point is positioned in a position distant from the widthwise center of the portion of the road surface.
• Fig. 4 is a cross sectional view of a shock absorber included in the suspension system, wherein flow of a working fluid upon downward movement of a piston is shown in a right side of an axis of the shock absorber while flow of the working fluid upon upward displacement of the piston is shown in a left side of the axis of the shock absorber, '
• Fig. 14 is a view showing a relationship between a turning radius of each wheel of the vehicle and a turning angle of each front wheel of the vehicle during turning of the vehicle!
• Fig. 19 is a flow chart showing a running-speed-basis gain determining routine program as a sub-routine program of the preview-gain determining routine program of Fig. 18;
• Fig. 21 is a flow chart showing an ordinary controlling routine program as another sub -routine program of the preview controlling routine program of Fig. 17;
• Fig. 28 is a flow chart showing an ordinary controlling routine program as a sub-routine program of the preview controlling routine program of Fig. 27;
• Fig. 33 is view conceptually showing another suspension that can be included in the suspension system
• the damping-characteristic controlling device 56 includes an electric motor 90, a motion converter 91 configured to convert a rotary motion of the electric motor 80 into a linear motion, and an adjusting rod 92 disposed in a through-hole 94, which is formed in the piston rod 64 and extends in an axial direction of the piston rod 64.
• the adjusting rod 92 is connected at its upper end portion to an output member of the motion converter 91, and is linearly moved relative to the piston rod 64 by rotation of the electric motor 90.
• a rotational angle of the electric motor 90 is detected by a rotational angle sensor 96. As shown in Fig.
• the vertical force generator 24 includes an elastic member in the form of a L-shaped bar 122 having a generally L shape as seen in its plan view and a drive source in the form of an actuator 124 configured to rotate the L-shaped bar 122 about an axis Ls.
• the L-shape bar 122 includes a laterally extending portion in the form of a shaft portion 130 which extends substantially in a width or lateral direction of the vehicle, and a non-parallel portion in the form of an arm portion 132 which is contiguous to the shaft portion 130 and which extends in a direction not parallel to the shaft portion 130, e.g., substantially in a rearward direction of the vehicle.
• the shaft portion 130 of the L-shaped bar 122 is connected to an output shaft 146 of the electric motor 140 via an output shaft 148 of the speed reducer 142, so that the rotation of the electric motor 140 is transmitted to the shaft portion 130 while a speed of the rotation is reduced.
• the electric motor 140 and the speed reducer 142 are arranged in series with each other within a housing 144.
• the output shaft 146 of the electric motor 140 and the output shaft 148 of the speed reducer 142 are held by the housing 144 via respective bearings 150, 152, so as to be rotatable relative to the housing 144.
• the speed reducer 142 is provided by a harmonic gear set, and includes a wave generator 157, a flexible gear (flexspline) 158 and a ring gear (circular spline) 160.
• the wave generator 157 includes an elliptic cam and a ball bearing fitted on an outer circumferential surface of the elliptic cam, and is fixed to an end portion of the motor output shaft 146.
• the flexible gear 158 is provided by a cup-shaped member having a circumferential wall portion that is elastically deformable, and a plurality of teeth (e.g., a total of 400 teeth in the present embodiment) formed on its outer circumferential surface.
• the coil spring 20, shock absorber 22 and L-shaped bar 122 as the elastic member are disposed in parallel with each other. Therefore, a load applied to the wheel 12 is received by cooperation of the coil spring 20, shock absorber 22 and Lrshaped bar 122.
• the electric motor 140 is in a reference angular position (the actuator 124 is placed in a reference state) in this state. Since the load is received mainly by the coil spring 20 in this state, it will be described that the load is received by the coli spring 20 in the following description.
• the actuator 124 can be provided in a portion of the vehicle body 14 which is more distant from the wheel 12, than in an arrangement in which the elastic member is provided by a straight rod. This is effective to increase a degree of freedom in designing a portion in the vicinity of the wheel 12.
• the switching element WHC is disposed between the high-level voltage terminal 234H and the terminal 230w, such that the high-level voltage terminal 234H and the terminal 23Ow are selectively connected to and disconnected from each other by operation of the switching element WHC.
• the switching element WLC is disposed between the low-level voltage terminal 234L and the terminal 23Ow, such that the low-level voltage terminal 234L and the terminal 23Ow are selectively connected to and disconnected from each other by operation of the switching element WLC.
• a switching element control circuit of the inverter 178 is operable to determine the angular position (electrical angle) of the electric motor 140 based on signals detected by respective three Hall elements HA, HB, HC (each indicated by reference "H" in Fig.
• the inverter 178 is connected to a battery 236 via a converter 232 that is cooperates with the battery 236 to constitute the power source.
• the electric power is not supplied from the battery 236 to the electric motor 140 even when the ON/OFF state of each switching element is changed.
• the ON/OFF state of each of the switching elements UHC, VHC, WHC (that are connected to the high-level voltage terminal 234H of the power source) is changed like in the controlled-power supplying mode.
• any one of the three switching elements ULC, VLC, WLC (that are connected to the lowlevel voltage terminal 234L of the power source) is not subjected to the dutyratio control.
• each of the three switching elements ULC, VLC, WLC is subjected to the dutyratio control, such that the duty ratio is held 0 (zero).
• the previewable time Tp is obtained by dividing a wheel base Lw of the vehicle by the running speed V, as expressed in the following expression:
• the preview gain G is set to 0 (zero) so that the preview control is not carried out.
• the limit time TL is a value of the previewable time which causes the control to be delayed relative to the actual vertical vibration of the rear wheel 12R by an amount corresponding to the one-eighth (l / 8) cycle of the vibration even if the control command value is outputted without the waiting time, as shown in Figs. 12 A and 12B.
• the frequency N of the vibration is low, the one-eighth-cycle corresponding time Tx is long whereby the limit time TL is short.
• the frequency N of the vibration is high, the one-eighth-cycle corresponding time Tx is short whereby the limit time TL is long.
• the frequency N is 3 Hz, which is a relatively high frequency in vibration commonly caused in the vehicle and which is a maximum frequency that can be handled by the actuator 124. Consequently, it is possible to determine a maximum value of the limit time TL as a threshold value that enables the actuator 124 to be handled. Where the maximum frequency that can be handled by the actuator 124 is 3 Hz, the maximum value of the limit time TL as the threshold value is defined by (TD - 1/24).
• the intermediate path may be represented by an average value of the turning radius of the front right wheel 12FR and the turning radius of the front left wheel 12FL, or may be represented by a path (turning radius) of a widthwise center point PF of a front-wheel side portion of the vehicle, as shown in Fig. 14.
• the center point PF is an intersection of a vertical surface containing a line Lv (which passes a center G of gravity of the vehicle and extends in a longitudinal direction of the vehicle) and an axis common to axles of the respective front right and left wheels 12FR, 12FL (i.e., a line passing through centers of the respective front right and left wheels 12FR, 12FL), during straight running of the vehicle on a horizontal road surface.
• Rf, "Rr” represent the turning radius Rf of the center point PF of the front-wheel side portion and the turning radius Rr of the center point PR of the rear-wheel side portion, respectively.
• the overlap width ⁇ WT can be obtained by subtracting a turning radius of an inside one of widthwise opposite ends of the tire of the front wheel 12F from a turning radius of an outside one of widthwise opposite ends of the tire of the rear wheel 12R.
• the overlap ratio Lap becomes smaller than 0 (zero) as the absolute value ⁇ w of the turning angle is increased to be larger than the predetermined value ⁇ wo-
• the overlap ratio Lap being smaller than 0 (zero) means that a first portion of the road surface over which the front wheel 12F passes over and a second portion of the road surface over which the rear wheel 12R passes over do not overlap with each other at all.
• the path difference ⁇ R between the front-wheel side and rear-wheel side portions becomes larger than the tire width WT, there is no amount of overlap so that the overlap ratio Lap becomes not larger than 0 (zero).
• the rotational direction of the motor 140 is changeable more quickly than in an arrangement in which the motor 140 is energized even in reduction of the absolute value of the target damping force FB*, thereby avoiding reduction of responsiveness of the motor 140.
• the frequency of the vertical vibration of the controlled wheel may be obtained also based on change of the sprung-portion absolute velocity or displacement of the sprung or unsprung portion. Further, the vibration frequency may be obtained also by using Fourier transform or the like.
• step Sl that is implemented to detect the sprung-portion acceleration Gu in the form of the acceleration of a portion of the vehicle body 14 which corresponds to the front left wheel 12FL as the detected wheel.
• step Sl is followed by step S2 that is implemented to detect the vehicle height H.
• step S3 is implemented to obtain the unsprung-portion absolute velocity VL.
• step S4 is implemented to determine the preview gain G.
• step S5 it is judged whether the determined preview gain G is 0 (zero) or not. [0125] When the preview gain is larger than 0 (zero), steps S6-S10 are implemented to carry out the preview control.
• the electric motor 140 Since the electric motor 140 is not energized during tendency of reduction of the target damping force FB*, the consumption of the electric power can be reduced as compared with an arrangement in which the electric current is supplied to the motor 140 even during the reduction of the target damping force FB*.
• step S9 is implemented to output, upon elapse of the waiting time TQ, the control command value in the same manner as in step S 107.
• the control command value may be a predetermined value so as to be stored, and the predetermined control command value is outputted upon elapse of the waiting time TQ.
• step S4 a preview-gain determining routine program as a sub -routine program of the preview controlling routine program is executed as shown in a flow chart of Fig. 18.
• a running-speed-basis gain Gv that may be referred to as also a preview-time-basis gain
• the vertical-force-generator control unit 170 included in the suspension ECU 168 includes portions which are assigned to store and execute the preview controlling routine program shown in the flow chart of Fig. 17 and the ordinary controlling routine program shown in the flow chart of Fig. 21 and which cooperate with the sprung-portion acceleration sensors 196 and the vehicle height sensors 198 to constitute a vertical force controller that functions as a damping-force controlling portion.
• the vertical force generator 24 functions as a damping force generator.
• the damping-force controlling portion serves also as a sprung-portion-basis controlling portion of the vertical force controller.
• the vertical force controller includes portions which are assigned to store and implement step S4 of the preview controlling routine program shown in the flow chart of Fig.
• the previewable time Tp does not necessarily have to be obtained for obtaining the running-speed-basis gain Gv and that the running-speed-basis gain Gv may be obtained based on the running speed V.
• the running-speed-basis gain Gv may be obtained based on the running speed V.
• the turning- state -basis gain GR it is not essential to obtain the overlap ratio.
• the turning-state-basis gain GR may be obtained based on the overlap width ⁇ WT or the path difference (turning radius difference).
• the damping force FB* may be controlled in accordance with so-called "skyhook damper theory".
• the target damping force FB* may be obtained in accordance with a rule different from that used in the arrangement in which the control is executed based on the unsprung-portion absolute velocity VL.
• the damping force is generated by controlling the vertical force generator 24.
• unsprung-portion displacement When the displacement XL of the second lower arm 46 (hereinafter simply referred to as "unsprung-portion displacement") is a displacement by which the second lower arm 46 is positioned on a lower side of its reference position (in which the second lower arm 46 is positioned when the electric motor 140 is in the above-described reference angular position), the target elastic force FB* is to act in the downward direction.
• the elastic force generated by the coil spring 20 is reduced with increase of the distance between the sprung and unsprung portions.
• the reduction of the elastic force of the coil spring 20 is compensated by the elastic force generated by the vertical force generator 24, for thereby restraining displacement of the vehicle body 14 as the sprung portion that could be caused by the displacement of the second lower arm 46.
• the preview control is performed by executing a preview controlling routine program represented by the flow chart of Fig. 25.
• step S3b is implemented to obtain the unsprung-portion displacement XL of the front left wheel 12FL (i.e., the displacement XL of the second lower arm 46 provided for the front left wheel 12FL) based on the detected value detected by the sprung-portion acceleration sensor 196 (provided for the portion of the vehicle body 14 which corresponds to the front left wheel 12FL) and the vehicle height H.
• step S6b is implemented to obtain the target elastic force (target vertical force) FB* based on the unsprung-portion displacement XL, the elastic modulus K and the preview gain G, then obtain the target rotational angle ⁇ M* based on the target elastic force FB*, and then obtain the supplied electric current i based on the target rotational angle ⁇ M*.
• the control command value is supplied to the inverter 178 of the vertical force generator 24 provided for the rear left wheel 12RL upon elapse of the waiting time TQ.
• the control command value is immediately outputted.
• the sprung-portion acceleration Gu in the form of the acceleration of the portion of the vehicle body 14 that corresponds to the front left wheel 12FL and the distance H between the sprung and unsprung portions are obtained.
• the frequency f of the vehicle body 14 is obtained in step S 105b, and it is judged whether the obtained frequency f is equal to or lower than the ordinarily-controllable maximum frequency fo.
• the frequency f may be obtained based on either the sprung-portion acceleration or the sprung-portion absolute velocity.
• An inner space of the housing 320 is partitioned, by the piston 322, into two fluid chambers 330, 332 that are connected to the pump 316, so that a working fluid can be pumped by the pump 316 from one of the two fluid chambers 330, 332 so as to be supplied to the other, and can be pumped by the pump 316 from the other of the two fluid chambers 330, 332 so as to be supplied to the one, whereby fluid pressures within the respective fluid chambers 330, 332 and stroke of the piston 322 are controllable.
• a working-fluid compensator 340 is provided in parallel with the hydraulic cylinder 314.
• the electric motor 318 of the hydraulic cylinder device 312 is controlled to generate a vertical force as a sum of an elastic force dependent on the unsprung-portion absolute velocity and a damping force based on skyhook damper theory.
• the vertical force corresponds to the hydraulic pressure generated by the hydraulic cylinder device 312.
• the load applied to the wheel is received by the coil spring 310 and the hydraulic cylinder device 312, there is a certain relationship between the hydraulic pressure generated by the hydraulic cylinder device 312 and an amount of displacement of the piston 322 from its reference position (in which the piston 322 is positioned when the electric motor 318 is placed in a free state).
• a central angle (Pfv-O-PR) can be regarded to be the same to the absolute value ⁇ w of the turning angle of the steerable wheel.
• the turning- state - basis gain GR is obtained based on the overlap ratio Lap, and then the preview gain G is obtained.
• the overlap width ⁇ WT represents a position of the detected portion relative to a portion of the road surface over which the tire of the wheel passes, i.e., a distance from the position of the detected portion to an outside end of the portion of the road surface (over which an outside one of widthwise opposite ends of the tire of the wheel passes over).
• the overlap width ⁇ WT is close to the tire width WT (i.e., ⁇ WT ⁇ WT)
• values such as the sprung-portion displacement XL, sprung-portion absolute velocity Vu and sprung/unsprung- portions relative velocity Vs can be obtained based on the projections and recesses (causing the unsprung-portion displacement) in a conceptual model, so that the preview control is performed based on the obtained values.
• the present embodiment can be carried out also with the suspensions shown in Figs. 29, 30 and 33.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Vehicle Body Suspensions (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40342439

Family Applications (1)

Country Status (3)

Cited By (3)

Families Citing this family (9)

Citations (5)

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• 2007
  • 2007-11-13 JP JP2007294015A patent/JP4968006B2/ja not_active Expired - Fee Related
• 2008
  • 2008-11-07 WO PCT/JP2008/070729 patent/WO2009063958A1/en active Application Filing
  • 2008-11-07 DE DE112008003044T patent/DE112008003044T5/de not_active Ceased

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