JP5135023B2 - Suspension characteristic control device - Google Patents

Description

  The present invention relates to a suspension characteristic control device that changes suspension characteristics, and more particularly, to a suspension characteristic control device that realizes reduction of vehicle body vibration in accordance with a change in load distribution caused by a slope of a traveling path.

  2. Description of the Related Art In recent years, various types of damping dampers that can change damping force have been developed as cylindrical dampers used in automobile suspensions. In a vehicle equipped with a variable damping force damper (hereinafter simply referred to as a damper), steering stability and ride comfort are improved by variably controlling the damping force of the damper according to the running state of the vehicle. For example, when turning, the body rolls in the left-right direction due to the inertial force (lateral acceleration) that accompanies lateral movement. To suppress excessive rolls at this time, the target damping force of the damper is based on the differential value of the lateral acceleration. Control (roll control) is performed to increase the speed. Also, during straight running, the wheels move up and down due to the unevenness of the road surface, but the target damping force is set according to the sprung speed in order to suppress transmission of the wheels to the vehicle body (vehicle vibration) and improve ride comfort. Control to increase (skyhook control) is performed (see Patent Document 1).

In skyhook control, a technique has been proposed in which the damping force is changed in accordance with the excitation from the road, that is, in accordance with the road surface condition, thereby improving the driving comfort (see Patent Document 2). In such an invention, skyhook control is performed by estimating the excitation state from the road based on the sprung acceleration or the like.
JP 2006-69527 A JP-A-5-69716

  However, the skyhook control in the prior art performs independent control for each wheel on the basis of the sprung acceleration corresponding to each wheel, so that, for example, the pitch and roll caused by the change in wheel load during running on an inclined road are suppressed. I couldn't.

  For example, when an automobile travels on an inclined road with a downward slope toward the traveling direction, the wheel load applied to the front wheel increases and the wheel load applied to the rear wheel decreases compared to when traveling on a horizontal road. Therefore, when traveling on a down slope, the natural frequency of the front wheels is reduced compared to when traveling on a horizontal road, while the natural frequency of the rear wheels is increased, so that the sprung speed between the front wheels and the rear wheels is also reduced. There is a difference. Therefore, when the skyhook control based on the sprung speed is performed independently for the front wheel and the rear wheel, as shown in FIG. 15, there is still a difference between the front wheel sprung speed and the rear wheel sprung speed even after the control. And a pitch is generated due to the difference in sprung speed. In order to suppress this pitch, it is necessary to control the pitch so that the sprung speed of the rear wheel increases.

  However, in the control device described in Patent Document 1, pitch control is performed based on the longitudinal acceleration of the vehicle body, and the above-described pitch also occurs when the vehicle is traveling on an inclined road without acceleration or deceleration. When running on the road, the pitch could not be properly suppressed. Similarly, when the road surface is inclined in the vehicle width direction, a roll due to a change in wheel load distribution is generated, but the conventional control device cannot appropriately suppress the roll.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a suspension characteristic control device capable of suppressing a change in the amount of motion of the vehicle body caused by a change in the distribution of wheel loads. To do.

  In order to solve the above problems, a first aspect of the present invention is a suspension characteristic control device that changes suspension characteristics by drivingly controlling a suspension element provided between a vehicle body and each wheel. Road surface inclination detecting means for detecting the inclination of the road, wheel load detecting means for detecting the wheel load of each wheel, and when the road surface inclination detecting means detects the inclination of the road surface, based on the detection result of the wheel load detecting means. Drive control means for driving and controlling the suspension element so that the vibration of the vehicle body is reduced (claim 1).

  According to this, it is possible to suppress the vibration of the vehicle body that occurs due to the change in the distribution of the wheel load when traveling on an inclined road, and to improve the riding comfort.

  In the suspension characteristic control device having the above-described configuration, the drive control unit sets a control parameter based on the momentum of the vehicle body, controls the suspension element for each wheel based on the control parameter, and further, the wheel The control parameter may be corrected based on the detection result of the load detection means.

  By configuring in this way, the parameter based on the vehicle momentum that is the basis of the conventional skyhook control is corrected according to the wheel load. Can be suppressed.

  The suspension characteristic control apparatus further includes a natural frequency calculating unit that calculates a natural frequency of each vehicle body part provided with the suspension element based on a detection result of the wheel load detecting unit, The drive control means may be configured to control the suspension element based on the calculation result of the natural frequency calculation means.

  According to this, since the suspension element is driven and controlled in accordance with the natural frequency of each suspension which varies depending on the change in wheel load, the vehicle vibration determined by the value of natural frequency and its amplitude can be obtained even when traveling on a slope. Can be suppressed.

  Further, in the suspension characteristic control device that performs suspension element drive control based on the natural frequency, when the suspension element is a damping force variable damper, and the drive control means detects a road surface inclination by the road surface inclination detection means. It is preferable that the damping force of the damping force variable damper is controlled so that the natural frequency amplitude of at least one vehicle body portion located on the upper side among the vehicle body portions is reduced.

  The frequency region that is considered to affect the ride comfort is generally about 2 to 8 Hz. By adopting the above configuration, among the vehicle body parts that have different natural frequencies when traveling on the slope, the upper vehicle body part, that is, the wheel load Since the amplitude of the vehicle body portion where the natural frequency is higher than when traveling on a horizontal road is reduced, the vibration affecting the riding comfort can be reduced even when traveling on an inclined road. Here, the time of traveling on a horizontal road is defined as a traveling state in which the road surface is horizontal in the vehicle traveling direction and the vehicle width direction, and the automobile V is traveling straight ahead at a constant speed without acceleration / deceleration or turning. To do.

  Alternatively, in the suspension characteristic control device that performs suspension element drive control based on the natural frequency, when the suspension element is a damping force variable damper, and the drive control means detects the road surface inclination by the road surface inclination detection means The damping force of the variable damping force damper may be controlled such that the amplitude of the natural frequency of at least one of the vehicle body parts located on the lower side among the vehicle body parts is increased (Claim 5). .

  According to this, among the vehicle body parts that have different natural frequencies when traveling on an inclined road, the lower vehicle body part, that is, the vehicle body part that has a lower natural frequency than when traveling on a horizontal road due to increased wheel load. By increasing the amplitude, it is possible to reduce the amplitude of the frequency region that affects the riding comfort and to improve the riding comfort when traveling on an inclined road.

  Further, in the suspension characteristic control device that performs suspension element drive control based on the natural frequency, when the drive control means detects the road surface inclination by the road surface inclination detection means, the natural frequency of each vehicle body part is calculated. The suspension element may be driven and controlled so as to approach the natural frequency when traveling on a horizontal road.

  For example, an active suspension such as an air suspension can change the natural frequency of each vehicle body part by changing the spring constant of the air spring, regardless of the wheel load. Even when traveling, it is possible to achieve the same riding comfort as when traveling on a horizontal road.

  In any configuration of the suspension characteristic control device, when the drive control unit is configured to switch to control that suppresses a change in the posture of the vehicle body when the road surface inclination detected by the road surface inclination detection unit is greater than or equal to a predetermined amount. Good (Claim 7).

  With this configuration, when the road surface has a large slope, it is possible to improve the riding comfort during running on the slope by suppressing the change in the posture of the vehicle in preference to improving the riding comfort by suppressing the vibration.

  ADVANTAGE OF THE INVENTION According to this invention, the vibration resulting from the wheel load which is different by each wheel can be suppressed also at the time of driving | running | working on a ramp, etc., and high-quality riding comfort can be implement | achieved.

<< Configuration of First Embodiment >>
Hereinafter, a first embodiment in which the present invention is applied to a four-wheeled vehicle will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a four-wheel vehicle according to the first embodiment, FIG. 2 is a longitudinal sectional view of a damper according to the first embodiment, and FIG. 3 is a diagram of the damping force control device according to the first embodiment. FIG. 4 is a block diagram illustrating a schematic configuration, FIG. 4 is a block diagram illustrating a configuration of a main part of a skyhook calculation control unit according to the first embodiment, and FIG. 5 illustrates a main part of the skyhook gain setting unit according to the first embodiment. It is a block diagram which shows a part structure. In the description, for the four wheels and the members arranged with respect to them, that is, tires, suspensions, etc., subscripts indicating front, rear, left and right are attached to the reference numerals, for example, wheel 3fl (front left). , Wheel 3fr (right front), wheel 3rl (left rear), wheel 3rr (right rear), and collectively referred to as wheel 3, for example.

<Schematic configuration of automobile>
First, a schematic configuration of the automobile according to the first embodiment will be described with reference to FIG. As shown in the figure, a vehicle body 1 of an automobile (vehicle) V has wheels 3 with tires 2 mounted on the front, rear, left and right thereof. These wheels 3 are each provided with a suspension arm 4, a coil spring 5, a damping force. It is suspended from the vehicle body 1 by a suspension 7 composed of a variable damper (hereinafter simply referred to as a damper) 6 or the like. In the vehicle V, in addition to an ECU (Electronic Control Unit) 8 used for various controls, a vehicle speed sensor 9, a lateral G sensor 10, a front / rear G sensor 11, a yaw rate sensor 12, and the like are installed at appropriate positions of the vehicle body 1. . Further, in the vehicle V, for each wheel 3fl to 3rr, a vertical G sensor 13 is installed at a vehicle body part near the vehicle body 1 side connecting portion of the damper 6 and a stroke sensor 14 is installed with respect to the damper 6.

  The ECU 8 includes a microcomputer, a ROM, a RAM, a peripheral circuit, an input / output interface, various drivers, and the like, and a damper for each wheel 3 via a communication line (CAN (Controller Area Network in this embodiment)). 6 and each sensor 9-14.

  As shown in FIG. 9, when the suspension 7 travels on a horizontal road, that is, when the vehicle body weight is distributed to each wheel 3 at a predetermined ratio, the natural frequency Fn of the vehicle body part corresponding to all the front, rear, left and right wheels 3 is obtained. Are set to be the same. 9, 10, 11 and 14 show the relationship between the amplitude ratio on the spring against the road surface vibration and the frequency. Since the amplitude ratio takes a logarithmic value (20 * log10x), the smaller the amplitude ratio, the smaller the amplitude ratio becomes. It shows that the amplitude on the spring is smaller than the amplitude of the road surface.

<Damper>
As shown in FIG. 2, the damper 6 of the present embodiment is a monotube type (de carvone type), and a cylindrical cylinder 22 filled with MRF (Magneto-Rheological Fluid), A piston rod 23 that slides in the axial direction with respect to the cylinder 22, a piston 26 that is attached to the tip of the piston rod 23 and divides the inside of the cylinder 22 into an upper oil chamber 24 and a lower oil chamber 25, and a lower portion of the cylinder 22 The main components are a free piston 28 defining a high-pressure gas chamber 27, a cover 29 for preventing dust from adhering to the piston rod 23 and the like, and a bump stop 30 for buffering at the time of full bound.

  The cylinder 22 is connected to the upper surface of the suspension arm 4 that is a wheel side member via a bolt 31 that is fitted into the eyepiece 22a at the lower end. The piston rod 23 is connected to a damper base (wheel house upper part) 34 that is a vehicle body side member via a pair of upper and lower rubber bushes 32 and a nut 33.

  The piston 26 is provided with a communication passage 41 that allows the upper oil chamber 24 and the lower oil chamber 25 to communicate with each other, and an MLV coil 42 that is positioned inside the communication passage 41. When a current is supplied from the ECU 8 to the MLV coil 42, a magnetic field is applied to the MRF flowing through the communication path 41, and the ferromagnetic fine particles form a chain cluster. As a result, the apparent viscosity of the MRF passing through the communication passage 41 (hereinafter simply referred to as viscosity) increases, and the damping force of the damper 6 increases.

<Schematic configuration of damping force control device>
As shown in FIG. 3, the ECU 8 includes a damping force control device 50 (suspension characteristic control device) that controls the damper 6. The damping force control device 50 includes the input interface 51 to which each of the sensors 9 to 14 is connected, the roll moment, the pitch moment, the sprung speed, and the like obtained from the detection signals of the sensors 9 to 13. Each damper 6 (MLV coil 42) according to the damping force setting unit 52 (drive control means) for setting the target damping force, the target damping force input from the damping force setting unit 52, and the stroke speed Ss input from the stroke sensor 14. ), And an output interface 54 that outputs the drive current generated by the drive current generator 53 to each damper 6.

  The damping force setting unit 52 includes a skyhook calculation control unit 55 used for skyhook control, a road surface inclination determination unit 56 for determining road inclination, a roll calculation control unit 57 used for roll control, and pitch control. The provided pitch calculation control unit 58 and the like are accommodated.

<Skyhook calculation control unit>
As shown schematically in FIG. 4, the skyhook calculation control unit 55 uses the vehicle speed signal v input from the vehicle speed sensor 9 and the vertical acceleration signal Gl (sprung speed acceleration detection value Gld) input from the vertical G sensor 13. The skyhook control base value Dsb (control parameter) is set based on the skyhook control base value setting unit 60 and the skyhook gain base unit Dsb is multiplied by the skyhook control base value Dsb. Each wheel 3 is provided with a skyhook control target value calculation unit 61 for calculating the hook control target value Dsh.

<Skyhook gain setting section>
As shown schematically in FIG. 5, the skyhook gain setting unit 59 includes a vehicle speed Vs input from the vehicle speed sensor 9, a stroke speed Ss input from the stroke sensor 14, and a yaw rate γ input from the yaw rate sensor 12. Based on the wheel load calculation unit 63 that calculates the wheel load Le of each wheel 3, the natural frequency calculation unit 64 that calculates the natural frequency Fn of each vehicle body part based on the calculation result of the wheel load calculation unit 63, A control gain setting unit 65 that sets the skyhook gain Gsh based on the calculation result of the frequency calculation unit 64 is provided.

<Road surface inclination judgment part>
The road surface inclination determination unit 56 determines the inclination of the road surface in the longitudinal direction of the vehicle body based on the vehicle speed Vs input from the vehicle speed sensor 9 and the longitudinal acceleration Gx input from the longitudinal G sensor 11, and the longitudinal inclination angle θx. Is calculated. Further, the road surface inclination determination unit 56 determines the road surface inclination in the vehicle width direction based on the lateral acceleration Gy input from the lateral G sensor 10 and the yaw rate γ input from the yaw rate sensor 12, and also in the vehicle width direction. The inclination angle θy is calculated.

<< Operation of First Embodiment >>
<Damping force control>
When the automobile starts traveling, the damping force control device 50 executes damping force control whose procedure is shown in the flowchart of FIG. 6 for each wheel at a predetermined processing interval (for example, 10 ms). When the damping force control is started, the damping force setting unit 52 determines the road surface inclination and calculates the road surface inclination angles θx and θy in the road surface inclination determination unit 56 (step 1). When it is determined in step 1 that there is no inclination on the road surface (No), the damping force setting unit 52 performs posture change suppression control described in detail later in the skyhook calculation control unit 55 (step 4). In this posture change suppression control, a skyhook control target value Dsh that is a target damping force of each damper 6 is set.

  On the other hand, if it is determined in step 1 that the road surface is inclined (Yes), the damping force setting unit 52 determines whether the road surface inclination angle calculated in step 1 is less than a predetermined angle in the skyhook calculation control unit 55. It is determined whether or not (step 2). When the inclination angle of the road surface is equal to or larger than the predetermined angle (No), the damping force setting unit 52 similarly performs the posture change suppression control process in the skyhook calculation control unit 55 (step 4). On the other hand, when the slope angle of the road surface is less than the predetermined angle (Yes), the damping force setting unit 52 performs slope vibration suppression control, which will be described in detail later, in the skyhook calculation control unit 55 (step 3). In this slope vibration suppression control, the skyhook control target value Dsh, which is the target damping force of each damper 6, is set as in the posture change suppression control.

  Next, based on the target damping force set by the slope vibration suppression control in step 3 or the attitude change suppression control in step 4, the damping force control device 50 causes the drive current generator 53 to display a predetermined target current map. The target current is searched / set with reference (step 5), the drive current is output to the MLV coil 42 of each damper 6 based on the target current set in step 5 (step 6), and the above procedure is repeated.

<Ramp vibration suppression control>
Next, the above-described ramp vibration suppression control will be described with reference to FIG. As shown in the figure, the damping force setting unit 52 first sets the skyhook control base value Dsb in the skyhook control base value setting unit 60 (step 11). Next, the damping force setting unit 52 calculates the wheel load Le of each wheel 3 in the wheel load calculation unit 63 in the skyhook gain setting unit 59 (step 12), and also in the natural frequency calculation unit 64, the step The natural frequency Fn of each vehicle body part is calculated based on the wheel load Le calculated in step 12 (step 13). Similarly, the control gain setting unit 65 calculates the natural frequency Fn of each wheel 3 based on the natural frequency Fn calculated in step 13. A skyhook gain Gsh is set (step 14).

  When the skyhook gain Gsh is set for each wheel 3 in step 14, the natural frequency Fn of the vehicle body part located above the road surface inclination determined by the road surface inclination determination unit 56 is reduced. Then, the skyhook gain Gsh is corrected, and the skyhook gain Gsh is corrected so that the amplitude of the natural frequency Fn of the vehicle body portion located on the lower side of the road surface slope is also increased.

  The damping force setting unit 52 multiplies the skyhook control base value Dsb set in step 11 by the natural frequency Fn calculated in step 13 in the skyhook control target value calculation unit 61, thereby The skyhook control target value Dsh of the damper 6 is calculated (step 15), and the process is completed.

<Attitude change suppression control>
The above-described posture change suppression control will be described with reference to FIG. As shown in the figure, the damping force setting unit 52 first determines the acceleration of the vehicle body 1 obtained from the lateral G sensor 10, the front / rear G sensor 11, and the vertical G sensor 13, Based on the vehicle speed input from the sensor 9, the steering speed input from the steering angle sensor (not shown), etc., the motion state of the vehicle V (the sprung speed at each wheel 3) is determined (step 21).

  Next, the damping force setting unit 52 calculates the skyhook control target value Dsh of each damper 6 based on the motion state of the vehicle V determined in step 21 in the skyhook calculation control unit 55 (step 22). The calculation control unit 57 calculates the roll control target value Dr of each damper 6 (step 23), and the pitch calculation control unit 58 calculates the pitch control target value Dp of each damper 6 (step 24). And the damping force setting part 52 calculates the skyhook control target value Dsh of each damper 6 (step 25), and completes a process.

<< Effects of First Embodiment >>
As described above, the natural frequency Fn of the suspension 7 is set so as to be the same for all of the front, rear, left and right when traveling on a horizontal road, but when traveling on an inclined road, the wheel load Le of each wheel 3 changes and tilts. It becomes larger on the lower side of the road and smaller on the upper side of the ramp. However, in the present embodiment, as shown in FIG. 10, the vehicle body part having different natural frequencies on the lower side and the upper side (for example, the front side and the rear side) due to the change in the wheel load Le during traveling on the slope road. Among them, since the skyhook gain Gsh is corrected so that the amplitude of the vehicle body part on the upper side of the ramp with the higher natural frequency becomes smaller, the vibration in the frequency range of 2 to 8 Hz, which is considered to affect riding comfort. Is reduced, and the ride comfort when traveling on an inclined road is improved.

  Moreover, as shown in FIG. 11, the amplitude of the lower vehicle body part becomes larger among the vehicle body parts that have different natural frequencies on the lower side and the upper side due to the change of the wheel load Le when traveling on the slope road. As described above, since the skyhook gain Gsh is corrected, the amplitude in the frequency region of 2 to 8 Hz that affects the riding comfort is reduced, and the riding comfort during running on the slope is improved.

  As described above, the gain corresponding to the natural frequency Fn of each suspension changed due to the change in the wheel load Le is multiplied to correct the skyhook control base value Dsb which is the basis of the conventional skyhook control. Since the damping force of the damper 6 is controlled, the vibration of the vehicle body that cannot be suppressed during the traveling on the slope by the conventional skyhook control is suppressed, and the riding comfort during the traveling on the slope is improved.

  Then, when the road surface has a large slope, switching from the slope vibration suppression control to the posture change suppression control improves the riding comfort by suppressing the vibration generated by the slope, and improves the riding comfort by suppressing the posture change of the vehicle body 1. This makes it possible to improve the overall ride comfort when running on ramps.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described. In the description, points that are essentially different from those of the first embodiment will be mainly described, and descriptions of matters having similar configurations and operations will be omitted. FIG. 12 is a schematic configuration diagram of a four-wheeled vehicle according to the second embodiment, and FIG. 13 is a block diagram illustrating a schematic configuration of an air suspension characteristic control device according to the second embodiment.

  First, a schematic configuration of the automobile V according to the second embodiment will be described with reference to FIG. In the description, members and components that have the same technical idea as the first embodiment will be described with the same reference numerals as those in the first embodiment. As shown in FIG. 12, each wheel 3 installed in the vehicle body 1 of the automobile (vehicle) V is attached to the vehicle body 1 by an air suspension 107 including a suspension arm 4, an air spring 105, a damping force variable damper 6, and the like. Suspended. As in the first embodiment, as shown in FIG. 9, the air suspension 107 has the same natural frequency Fn of the vehicle body part corresponding to all the front, rear, left, and right wheels 3 when traveling on a horizontal road.

<Air spring>
Since the air spring 105 of the present embodiment has a known configuration, detailed illustration is omitted, but as its main component, a cylindrical air coupled to the outer periphery of the cylinder 22 of the damper 6 is used. The piston is connected to the piston rod 23 of the damper 6 and is connected to a cylindrical air chamber having a diameter larger than that of the air piston, to the air piston and the air chamber, and to allow relative movement in the axial direction between the air piston and the air chamber. A flexible diaphragm that is connected to the lower end of the air chamber and has a cylindrical cover that accommodates the diaphragm. The air chamber defined by the air piston, the air chamber, and the diaphragm is connected to the other end of the air supply pipe, one end of which is connected to the air compressor or the air tank. By discharging air from the air, the pressure in the air chamber is variably controlled, and the spring constant of the air spring 105 can be adjusted.

<Schematic configuration of damping force control device>
As shown in FIG. 13, the ECU 8 includes a suspension characteristic control device 150 that controls the damper 6. The suspension characteristic control device 150 is based on the damping force setting unit 52 (drive control means) that sets the target damping force of each damper 6 based on the detection signals of the sensors 9 to 13 and also based on the detection signals of the sensors 9 to 13. A spring constant control unit 101 (drive control means) that sets a target spring constant of each air spring 105 and a drive current generation that generates a drive current to each damper 6 according to the target damping force input from the damping force setting unit 52 A drive current generator 102 that generates a drive current to an air compressor or pressure control valve that controls the pressure to each air spring 105 according to the target spring constant input from the unit 53, the spring constant control unit 101, and a drive current The output unit 54 outputs the drive current generated by the generation unit 53 and the drive current generation unit 102 to each damper 6. That.

<Spring constant control unit>
The spring constant control unit 101 is cooperatively controlled together with the damping force setting unit 52, and when the road surface inclination determination unit 56 detects the road surface inclination, the natural frequency of each vehicle body part changed with the change in the wheel load Le. The spring constant of each air spring 105 is variably controlled so that Fn approaches the natural frequency Fn when traveling on a horizontal road.

<Spring constant control procedure>
Next, the spring constant control procedure will be described. In the flowchart of FIG. 6, the suspension characteristic control device 150 is parallel to the posture change suppression control (step 3) in the skyhook calculation control unit 55 when the slope of the road surface is equal to or larger than a predetermined angle in step 2 (No). In the spring constant control unit 101, by setting the target spring constant of each air spring 105 based on the detection signals of the sensors 9 to 13, the natural frequency Fn of each vehicle body part that has changed with the change in the wheel load Le is obtained. The spring constant of each air spring 105 is controlled so as to approach the natural frequency when traveling on a horizontal road.

<Effects of Second Embodiment>
In the configuration of the first embodiment, it was possible to improve the riding comfort by changing the amplitude of each vehicle body part by correcting the damping force of the damper 6, but the natural frequency Fn of the coil spring 5 itself was changed. Therefore, the natural frequency Fn of the vehicle body part cannot be controlled when the distribution of the wheel load Le is changed by traveling on the slope. However, in this embodiment, by changing the spring constant of the air spring 105, the natural frequency Fn of each vehicle body part can be changed regardless of the wheel load Le. Therefore, as shown in FIG. By driving and controlling the air spring 105 so that the natural frequency becomes close to the natural frequency at the time of traveling on a horizontal road, the same riding comfort as that at the time of traveling on a horizontal road is realized even when traveling on an inclined road.

  Although the description of the specific embodiment is finished as described above, it is needless to say that the aspect of the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the gist of the present invention.

Schematic configuration diagram of a four-wheeled vehicle according to the first embodiment 1 is a longitudinal sectional view of a damper according to a first embodiment. The block diagram which shows schematic structure of the damping-force control apparatus which concerns on 1st Embodiment. The block diagram which shows the principal part structure of the skyhook calculation control part which concerns on 1st Embodiment. The block diagram which shows the principal part structure of the skyhook gain setting part which concerns on 1st Embodiment. The flowchart which shows the procedure of damping force control which concerns on 1st Embodiment. The flowchart which shows the procedure of the ramp vibration suppression control which concerns on 1st Embodiment. The flowchart which shows the procedure of the attitude | position change suppression control which concerns on 1st Embodiment. The graph which shows the natural frequency of each vehicle body part at the time of the horizontal road driving | running | working which concerns on 1st Embodiment. The graph which shows the natural frequency of each vehicle body site | part at the time of controlling a damper damping force at the time of ramp running based on 1st Embodiment The graph which shows the natural frequency of each vehicle body site | part at the time of controlling a damper damping force at the time of ramp running based on 1st Embodiment Schematic configuration diagram of a four-wheeled vehicle according to a second embodiment The block diagram which shows schematic structure of the air suspension characteristic control apparatus which concerns on 2nd Embodiment. The graph which shows the natural frequency of each vehicle body site | part at the time of controlling a damper damping force at the time of ramp running based on 2nd Embodiment Graph showing the sprung speed when damping force control is performed in the prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 3 Wheel 5 Coil spring 6 Damper 7 Suspension 50 Damping force control device (suspension characteristic control device)
52 Damping force setting unit (drive control means)
55 Skyhook calculation control unit 56 Road surface inclination determination unit 57 Roll calculation control unit 58 Pitch calculation control unit 59 Skyhook gain setting unit 60 Skyhook control base value setting unit 62 Skyhook control target value calculation unit 63 Wheel load calculation unit 64 Specific Frequency calculation unit 65 Control gain setting unit 105 Air spring 107 Air suspension Dsb Skyhook control base value (control parameter)

Claims (5)

A suspension characteristic control device that changes suspension characteristics by driving and controlling a damping force variable damper provided between a vehicle body and each wheel,
Road surface inclination detecting means for detecting the road surface inclination;
A wheel load detecting means for detecting the wheel load of each wheel;
Drive control means for driving and controlling the variable damping force damper so that vibration of the vehicle body is reduced based on the detection result of the wheel load detection means when the road slope is detected by the road slope detection means;
A natural frequency calculating means for calculating the natural frequency of each vehicle body part provided with the damping force variable damper based on the detection result of the wheel load detecting means;
The drive control means drives and controls the damping force variable damper based on the calculation result of the natural frequency calculation means, and when the road surface inclination detection means detects the inclination of the road surface, The suspension characteristic control device characterized by controlling the damping force of the damping force variable damper so that the amplitude of the natural frequency of at least one vehicle body part located on the upper side becomes small. A suspension characteristic control device that changes suspension characteristics by driving and controlling a damping force variable damper provided between a vehicle body and each wheel,
Road surface inclination detecting means for detecting the road surface inclination;
A wheel load detecting means for detecting the wheel load of each wheel;
Drive control means for driving and controlling the variable damping force damper so that vibration of the vehicle body is reduced based on the detection result of the wheel load detection means when the road slope is detected by the road slope detection means;
A natural frequency calculating means for calculating the natural frequency of each vehicle body part provided with the damping force variable damper based on the detection result of the wheel load detecting means;
The drive control means drives and controls the damping force variable damper based on the calculation result of the natural frequency calculation means, and when the road surface inclination detection means detects the inclination of the road surface, A suspension characteristic control device for controlling the damping force of the damping force variable damper so that the amplitude of the natural frequency of at least one vehicle body part located on the lower side is increased. The drive control means sets a control parameter based on the momentum of the vehicle body, controls the damping force variable damper for each wheel based on the control parameter, and further, based on the detection result of the wheel load detection means The suspension characteristic control device according to claim 1 or 2, wherein the control parameter is corrected. The drive control means drives and controls the spring constant variable spring so that the natural frequency of each vehicle body part approaches the natural frequency when traveling on a horizontal road when the road surface inclination detecting means detects the road surface inclination. The suspension characteristic control device according to any one of claims 1 to 3, wherein   5. The drive control unit according to claim 1, wherein when the road surface inclination detected by the road surface inclination detection unit is greater than or equal to a predetermined amount, the drive control unit switches to control that suppresses a change in the posture of the vehicle body. The suspension characteristic control device according to claim 1.

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