Suspension control device and suspension control method

Abstract

To provide a suspension control device and a suspension control method that can appropriately control road surface vibration transmitted to a vehicle body while travelling and can reduce power consumption by estimating a road surface shape in the front of a vehicle and changing drive of an active suspension and a damper on the basis of this information.SOLUTION: In a suspension control device for controlling a suspension device attached to a wheel of a movable body, the suspension device comprises an active suspension which can adjust a vehicle height, and a damper which can adjust damping force. The suspension control device comprises: road surface shape measurement means which acquires a road surface shape; actuator control means which controls drive of the suspension device; and actuator drive selection means which changes drive of the suspension device on the basis of information acquired by the road surface shape measurement means.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a suspension control device and a suspension control method for controlling a suspension device attached to a wheel of an automobile or the like.

Background Art

[0002] Conventionally, a vehicle equipped with a suspension device that combines an active suspension capable of driving an electromagnetic actuator to change the vehicle height and a damper capable of suppressing high-frequency vibrations is known. Although various structures of such a suspension device are known, for example, as shown in Patent Document 1, between a wheel and a vehicle body, there is provided a support means that is elastically supported in the vertical direction within a predetermined stroke range and elastically supports the weight of the vehicle, an electromagnetic actuator that receives the vertical force of the wheel and complements the support of the support means, and an actuator control means that controls the energization of the electromagnetic actuator. In the suspension device, there is provided a terminal position detection means for detecting that the stroke position of the support means is near the terminal position of its telescopic movable stroke range. When the actuator control means detects that the stroke position of the support means is near the terminal position by the terminal position detection means, the control mode of the electromagnetic actuator is changed. The electromagnetic actuator is composed of a screw means having a male screw member and a female screw member that mesh with each other, and a motor that rotates the male screw member or the female screw member of the screw means to drive the screw means to expand and contract. A suspension device is known in which at least one of the screw means or the motor is connected to the wheel or the vehicle body via damper means and elastically supported via spring means.

[0003] According to such a suspension device, when the support means and the damper means approach the stoppers that regulate the up and down strokes respectively, the energization control of the electromagnetic actuator can be changed so that the support means and the damper means are less likely to approach the stoppers. As a result, the damper means removes high-frequency vibrations from the road surface, suppresses the shock caused by hitting the stopper, and can improve the riding comfort of the passengers. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2007-203933 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, conventional suspension systems use active suspension and dampers simultaneously without distinguishing between road surface vibrations and bump heights, resulting in the active suspension being activated even for minor vibrations, leading to high power consumption.

[0006] Furthermore, when removing high-frequency vibrations from the road surface, a response delay occurs in the active suspension's drive, which increases the burden on the damper's control and worsens the vibration suppression performance.

[0007] The present invention has been made to solve the above problems, and aims to provide a suspension control device and suspension control method that can appropriately suppress road vibrations transmitted to the vehicle body during driving and reduce power consumption by estimating the shape of the road surface in front of the vehicle and changing the drive of the active suspension and damper based on this information. [Means for solving the problem]

[0008] The suspension control device according to the present invention, which solves the above problems, is a suspension control device for controlling a suspension device attached to the wheels of a moving body, wherein the suspension device comprises an active suspension capable of adjusting the vehicle height and a damper capable of adjusting the damping force, and includes a road surface shape measuring means for acquiring the road surface shape, an actuator control means for controlling the drive of the suspension device, and an actuator drive selection means for distributing the drive ratio between the active suspension and the damper based on the information acquired by the road surface shape measuring means, wherein the drive ratio is The ratio of driving the active suspension and the ratio of driving the damper are defined. The aforementioned active suspension to maintain the vehicle's posture Control force and the damper This is to suppress body vibrations The sum of the control force and the unevenness of the road surface To absorb It is characterized by its ability to provide control.

[0009] Furthermore, the suspension control method according to the present invention, which solves the above problems, is a suspension control method for controlling a suspension device attached to the wheels of a moving body, wherein the suspension device comprises an active suspension capable of adjusting the vehicle height and a damper capable of adjusting the damping force, and comprises a road surface shape measurement step for acquiring the road surface shape, an actuator control step for controlling the drive of the suspension device, and an actuator drive selection step for distributing the drive ratio between the active suspension and the damper based on the information acquired by the road surface shape measurement step, wherein the drive ratio is The ratio of driving the active suspension and the ratio of driving the damper are defined. The aforementioned active suspension to maintain the vehicle's posture Control force and the damper This is to suppress body vibrations The sum of the control force and the unevenness of the road surface To absorb It is characterized by its ability to provide control. [Effects of the Invention]

[0010] According to the suspension control device and suspension control method of the present invention, the road surface shape in front of the vehicle is measured, the frequency and height of the step are estimated, and based on this information, either the active suspension or the damper is selected to be driven, or both are combined and the ratio of the control force is changed to drive them, thereby appropriately suppressing road surface vibrations transmitted to the vehicle body during driving. Furthermore, by driving either the active suspension or the damper, or both, in combination as needed, power consumption can be reduced. [Brief explanation of the drawing]

[0011] [Figure 1] A schematic diagram of a vehicle equipped with a suspension control device according to an embodiment of the present invention. [Figure 2] A schematic diagram illustrating a suspension device according to an embodiment of the present invention. [Figure 3] A block diagram showing the configuration of a suspension control device according to an embodiment of the present invention. [Figure 4] An explanatory diagram showing the division of control areas according to the road surface shape when switching between active suspension and damper drive. [Figure 5] An explanatory diagram illustrating the vibration suppression effect of the suspension control method according to an embodiment of the present invention. [Figure 6] An explanatory diagram showing the drive ratio of the active suspension according to the road surface shape. [Figure 7] An explanatory diagram showing the drive ratio of the active suspension and dampers according to the road surface shape. [Figure 8] A block diagram showing the configuration of a suspension control device according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the suspension control device according to the present invention will be described with reference to the drawings. Note that the following embodiments do not limit the invention according to each claim, and not all combinations of features described in the embodiments are essential for the solution means of the invention.

[0013] FIG. 1 is a schematic diagram of a vehicle equipped with a suspension control device according to an embodiment of the present invention, FIG. 2 is a schematic diagram for explaining a suspension device according to an embodiment of the present invention, and FIG. 3 is a block diagram showing the configuration of a suspension control device according to an embodiment of the present invention.

[0014] As shown in FIG. 1, a vehicle 1 equipped with a suspension control device according to the present embodiment has wheels 2 arranged at the four corners of the front, rear, left, and right of the vehicle 1 and a suspension device 3. The wheels 2 are attached to the vehicle body via suspension arms so as to be vertically movable with respect to the vehicle body.

[0015] As shown in FIG. 2, the suspension device 3 is attached between each wheel 2 and the vehicle body, softens vibrations and impacts input from the road surface, maintains the posture of the vehicle body, and ensures driving stability. The suspension device 3 has an active suspension 31 and a damper 32.

[0016] The active suspension 31 includes a spring that is a compression coil spring and a vehicle height adjustment actuator 31a that suppresses the movement of the oscillating spring and can adjust the height of the vehicle body from the ground.

[0017] The spring supports the vehicle weight and determines the amount of inclination of the vehicle body in the front, rear, left, and right directions generated during driving according to the stiffness of the spring. The spring expands and contracts according to the unevenness of the road surface and maintains the wheels 2 from leaving the road surface. Although the spring has been described as a compression coil spring, it is not limited thereto, and a torsion bar may be used.

[0018] The ride height adjustment actuator 31a includes, for example, a ball screw mechanism in which a ball screw and a ball screw nut are screwed together, and generates a damping force from the resistance force of a motor that is generated by the vertical extension and retraction movement of the ball screw mechanism. Furthermore, the damping force can be adjusted by the thrust force of the ball screw mechanism that extends and retracts vertically when the motor is energized. In addition, by driving the motor and extending and retracting the ball screw mechanism vertically in this way, the overall length of the active suspension 31 can be extended or retracted, and the height of the vehicle body from the ground can be adjusted by changing the distance between the wheels 2 and the vehicle body.

[0019] With such an active suspension 31, even when there are bumps or unevenness on the road surface with significant height differences, the vehicle's posture can be maintained by changing the distance between the wheels 2 and the vehicle body.

[0020] On the other hand, since such an active suspension 31 operates the motor through the vertical extension and retraction of a ball screw mechanism, a response delay occurs when the vibrations caused by road surface irregularities received by the wheels 2 during driving are of a high frequency. Also, when adjusting the vehicle height using the active suspension 31, power consumption is high because the motor's torque is used to extend and retract the ball screw mechanism vertically.

[0021] The damper 32 is a rotary damper that utilizes the damping force generated by magnetorheological resistance. The damper 32 is equipped with a variable damper actuator 32a that allows the damping force to be adjusted by current control.

[0022] The variable damper actuator 32a is held, for example, by bearings so that its rotating shaft can rotate relative to the main body case. The main body case contains a coil and a rotor, and the rotating shaft is attached to the rotor. There is a gap around the rotor, and this gap is filled with magnetic fluid. When current is passed through the coil of such a variable damper actuator 32a, the viscous resistance of the filled magnetic fluid increases, generating a force that opposes the rotation of the rotor. By controlling the current input to the coil in this way, the variable damper actuator 32a can adjust the damping force of the damper 32.

[0023] With this type of damper 32, damping force can be generated electrically, resulting in excellent responsiveness and the ability to suppress vibrations of the vehicle body even when there are high-frequency bumps on the road surface while driving. Furthermore, because the viscous resistance of the magnetic fluid can be adjusted steplessly, it is possible to control the current to the minimum necessary to generate the required torque, thereby reducing power consumption.

[0024] On the other hand, compared to the active suspension 31, such a damper 32 has a shorter adjustment distance for changing the distance between the wheel 2 and the vehicle body, and can handle lower road surface step heights.

[0025] Although damper 32 was described as a damper whose damping force can be adjusted by current control, the structure of damper 32 is not limited to this, and it may be a damper with a constant damping force. Furthermore, although damper 32 was described as a rotary damper that utilizes the damping force generated by the viscous resistance of magnetic fluid, it is not limited to this, and may also utilize the damping force generated by the viscous resistance of oil. It may also be a cylinder-type damper.

[0026] Next, the suspension control device 4 according to this embodiment will be described. As shown in Figures 1 and 3, the suspension control device 4 includes a forward sensor 41 (road surface shape measuring means in the claims), an actuator drive selection device 42 (actuator drive selection means in the claims), and an actuator control device 5 (actuator control means in the claims).

[0027] The forward sensor 41 is mounted, for example, on the front of the vehicle and acquires the height and frequency of unevenness in the road surface in front of the vehicle. For example, the forward sensor 41 can be a camera or a radar-type sensor. The forward sensor 41 is not limited to being mounted on the front of the vehicle; it can be mounted anywhere that can measure the road surface in front of the vehicle, such as on the underside of the vehicle or around the windshield.

[0028] The actuator drive selection device 42 changes the driving method of the suspension device 3 based on information acquired by the forward sensor 41. The actuator drive selection device 42 has a microprocessor as a control means and operates by power supply from a battery (not shown). The actuator drive selection device 42 includes a road surface shape estimation unit 43 and a control selection unit 44.

[0029] The road surface shape estimation unit 43 estimates the step height and step frequency of the unevenness in the road surface located directly beneath the wheels 2 at the time the wheels 2 pass over it during driving, based on the road surface shape information in front of the vehicle acquired by the forward sensor 41.

[0030] The control selection unit 44 calculates the control force required for the suspension device 3 to maintain the vehicle's posture based on the information estimated by the road surface shape estimation unit 43. Based on the required control force for the suspension device 3, the control selection unit 44 determines how to drive the vehicle height adjustment actuator 31a and the variable damper actuator 32a, and sends signals to the changeover switches 55 and 65, which will be described later.

[0031] In this way, the actuator drive selection device 42 estimates the road surface shape at the time the wheels 2 pass over it during driving, based on information about the road surface shape in front of the vehicle, and controls the driving of the active suspension 31 or the damper 32 according to the road surface shape.

[0032] The actuator control device 5 includes an unsprung weight sensor 51 (means for measuring road surface frequency as defined in the claims), a vehicle height adjustment actuator control unit 52, a sprung weight sensor 61 (means for acquiring attitude information as defined in the claims), and a variable damper actuator control unit 62.

[0033] The unsprung weight sensor 51 measures vibrations received from the road surface over which the wheels 2 pass and transmits a signal to the vehicle height adjustment actuator control unit 52. The unsprung weight sensor 51 is an acceleration sensor mounted between the active suspension 31 and the wheels 2, and is mounted corresponding to each of the wheels 2 located at the four corners of the vehicle 1.

[0034] The vehicle height adjustment actuator control unit 52 has a microprocessor as a control means and operates by power supplied from a battery (not shown). The vehicle height adjustment actuator control unit 52 includes a road surface unevenness calculation unit 53 and a target vehicle height calculation unit 54.

[0035] The road surface unevenness calculation unit 53 calculates the step height and step frequency of the actual road surface unevenness located directly beneath the wheel 2, based on the information acquired by the unsprung weight sensor 51.

[0036] The target vehicle height calculation unit 54 calculates the amount of extension and contraction of the active suspension 31 necessary to maintain the vehicle's posture based on the information calculated by the road surface unevenness calculation unit 53, and sends a signal to the vehicle height adjustment actuator 31a.

[0037] The target vehicle height calculation unit 54 and the vehicle height adjustment actuator 31a are connected via a changeover switch 55. The changeover switch 55 controls the signal input to the vehicle height adjustment actuator 31a based on the signal from the control selection unit 44.

[0038] The changeover switch 55 connects the signal transmitted from the target vehicle height calculation unit 54 to the vehicle height adjustment actuator 31a, driving the vehicle height adjustment actuator 31a to extend or retract the overall length of the active suspension 31 according to the extension or retraction amount calculated by the target vehicle height calculation unit 54. Alternatively, the changeover switch 55 disconnects the signal transmitted from the target vehicle height calculation unit 54, fixing the operation of the vehicle height adjustment actuator 31a so that the overall length of the active suspension 31 does not change. As a method for fixing the operation of the vehicle height adjustment actuator 31a, for example, the changeover switch 55 may be used to drive an electromagnetic ON / OFF valve and mechanically lock the ball screw mechanism of the vehicle height adjustment actuator 31a.

[0039] Although the description has focused on the case where the changeover switch 55 connects or disconnects the signal transmitted from the target vehicle height calculation unit 54, the changeover switch 55 is not limited to this case. It may also modify the signal transmitted from the target vehicle height calculation unit 54 based on information sent from the control selection unit 44, thereby continuously changing the extension / retraction amount or damping force of the active suspension 31 by the vehicle height adjustment actuator 31a.

[0040] The sprung mass sensor 61 measures the vertical acceleration during driving and transmits a signal to the variable damper actuator control unit 62. The sprung mass sensor 61 is an acceleration sensor mounted between the active suspension 31 and the vehicle body, and is mounted corresponding to the portion of the vehicle body directly above each of the four wheels 2 located at the four corners of the vehicle 1.

[0041] The variable damper actuator control unit 62 has a microprocessor as a control means and operates by power supplied from a battery (not shown). The variable damper actuator control unit 62 includes a vehicle body attitude calculation unit 63 and a damping force calculation unit 64.

[0042] The vehicle body attitude calculation unit 63 calculates the actual vehicle body attitude, the vertical velocity and vertical displacement behavior obtained by integrating the vertical acceleration of the four corners of the vehicle body, etc., based on the information acquired by the sprung mass sensor 61, and transmits a signal to the damping force calculation unit 64.

[0043] The damping force calculation unit 64 calculates the damping force of the damper 32 necessary to stabilize the vehicle's posture based on the information calculated by the vehicle posture calculation unit 63, and sends a signal to the variable damper actuator 32a.

[0044] The damping force calculation unit 64 and the variable damper actuator 32a are connected via a changeover switch 65. The changeover switch 65 controls the signal input to the variable damper actuator 32a based on the signal from the control selection unit 44.

[0045] The changeover switch 65 connects the signal transmitted from the damping force calculation unit 64 to the variable damper actuator 32a, and changes the damping force of the variable damper actuator 32a according to the damping force calculated by the damping force calculation unit 64. Alternatively, the changeover switch 65 disconnects the signal transmitted from the damping force calculation unit 64, fixing the damping force of the variable damper actuator 32a to an arbitrary value.

[0046] Although the description has focused on the case where the changeover switch 65 connects or disconnects the signal transmitted from the damping force calculation unit 64, the changeover switch 65 is not limited to this case. It may also change the signal transmitted from the damping force calculation unit 64 based on information sent from the control selection unit 44, thereby continuously changing the damping force of the damper 32 by the variable damper actuator 32a.

[0047] Next, in the suspension control device 4 according to this embodiment, a method for determining the switching of the drive of the vehicle height adjustment actuator 31a and the variable damper actuator 32a by the actuator drive selection device 42, or a method for determining the ratio in which both are driven, will be explained based on the following embodiment.

[0048] [First Embodiment] Figure 4 is an explanatory diagram showing the division of control areas according to the road surface shape for switching between the drive of the active suspension 31 and the damper 32, and Figure 5 is an explanatory diagram showing the vibration suppression effect of the suspension control method according to an embodiment of the present invention.

[0049] In the first embodiment, as shown in Figure 4, the drive of the vehicle height adjustment actuator 31a and the variable damper actuator 32a is controlled according to the step height and step frequency of the road surface located directly below the wheels 2 while driving, as estimated by the road surface shape estimation unit 43.

[0050] Specifically, when the height of the step in the road surface is high and the step frequency in the road surface is low (region A in Figure 4), the actuator drive selection device 42 controls the changeover switch 55 to connect the signal sent from the vehicle height adjustment actuator control unit 52 to the vehicle height adjustment actuator 31a. The actuator drive selection device 42 also controls the changeover switch 65 to disconnect the signal sent from the variable damper actuator control unit 62 and fix the damping force of the variable damper actuator 32a to a predetermined value.

[0051] Thus, when the height of the road surface step is high and the frequency is low, only the ride height adjustment actuator 31a is driven variably to maintain the vehicle's posture. In this case, since the damping force of the variable damper actuator 32a is fixed, the power consumption required to drive the damper 32 can be reduced.

[0052] Furthermore, as in the conventional suspension control method shown in Figure 5, when adjusting the vehicle height by the active suspension 31 and adjusting the damping force by the damper 32 simultaneously on a road surface with a high step height and low step frequency (range E in Figure 5), the direction of the force that the active suspension 31 tries to generate and the direction of the force generated by the damper 32 may be in opposition. In this case, an increase in the amount of change in vehicle height may occur, potentially worsening the ride comfort. As in this embodiment, by variably driving the vehicle height adjustment actuator 31a and fixing the damping force of the variable damper actuator 32a, and performing only the vehicle height adjustment by the active suspension 31, it is possible to suppress the increase in the amount of change in vehicle height and prevent deterioration of ride comfort.

[0053] Furthermore, when the height of the step in the road surface is low and the step frequency of the road surface is low (region B in Figure 4), the actuator drive selection device 42 controls the changeover switch 55 to disconnect the signal sent from the vehicle height adjustment actuator control unit 52 and fix the operation of the vehicle height adjustment actuator 31a. The actuator drive selection device 42 also controls the changeover switch 65 to connect the signal sent from the variable damper actuator control unit 62 to the variable damper actuator 32a.

[0054] Thus, when the height of the road surface step is low and the frequency is low, only the variable damper actuator 32a is driven variably to maintain the vehicle's posture. In this case, since the operation of the ride height adjustment actuator 31a is fixed, the power consumption required to drive the active suspension 31 can be reduced.

[0055] Furthermore, when the height of the step in the road surface is low and the step frequency in the road surface is high (region C in Figure 4), the actuator drive selection device 42 controls the changeover switch 55 to disconnect the signal sent from the vehicle height adjustment actuator control unit 52 and fix the operation of the vehicle height adjustment actuator 31a. Also, the actuator drive selection device 42 controls the changeover switch 65 to disconnect the signal sent from the variable damper actuator control unit 62 and fix the damping force of the variable damper actuator 32a to a predetermined value.

[0056] Thus, when the height of the road surface step is low and the frequency is high, the operation of the ride height adjustment actuator 31a and the damping force of the variable damper actuator 32a can be fixed, thereby reducing the power consumption required to drive the active suspension 31 and the damper 32.

[0057] Furthermore, as in the conventional suspension control method shown in Figure 5, if the vehicle height adjustment by the active suspension 31 and the damping force adjustment by the damper 32 are performed simultaneously on a road surface with a low step height and high step frequency (range D in Figure 5), the response delay of the active suspension 31 may prevent the vehicle height from being adjusted at the appropriate timing, potentially leading to excessive lowering of the vehicle height or an increase in the amount of change in vehicle height, resulting in a deterioration of ride comfort. In this embodiment, when driving on a road surface where the vehicle's posture can be maintained solely by the damping force of the damper 32, the operation of the vehicle height adjustment actuator 31a is fixed, and the damping force of the variable damper actuator 32a is varied or fixed. By suppressing the vibration of the vehicle body solely by the damping force of the damper 32, the increase in the amount of change in vehicle height can be suppressed, and a deterioration of ride comfort can be prevented.

[0058] [Second Example] Figure 6 is an explanatory diagram showing the drive ratio of the active suspension according to the road surface shape, and Figure 7 is an explanatory diagram showing the drive ratio of the active suspension and damper according to the road surface shape.

[0059] In the second embodiment, as shown in Figure 6, the ratio in which the vehicle height adjustment actuator 31a and the variable damper actuator 32a are driven is changed according to the step height and step frequency of the road surface located directly below the wheels 2 of the moving vehicle 1, as estimated by the road surface shape estimation unit 43.

[0060] Specifically, when the height of the road surface step is high and the frequency of the road surface step is low (region F in Figure 6), first, the actuator drive selection device 42 calculates the control force of the suspension device 3 necessary to maintain the vehicle's posture based on the road surface shape information in front of the vehicle acquired by the forward sensor 41. Next, the actuator drive selection device 42 controls the changeover switches 55 and 65 so that the signal sent from the vehicle height adjustment actuator control unit 52 is connected to the vehicle height adjustment actuator 31a so that the control force of the active suspension 31 becomes 100% of the required control force of the suspension device 3.

[0061] Thus, when vehicle 1 is traveling on a road surface with a high step height and low step frequency, as shown in Figure 7, the actuator drive selection device 42 sends signals to the changeover switches 55 and 65 to drive the vehicle height adjustment actuator 31a and fix the damping force of the variable damper actuator 32a to a predetermined value, so that 100% of the control force required to absorb the unevenness of the road surface is the control force of the damping force of the active suspension 31.

[0062] Furthermore, when the height of the road surface step is low and the frequency of the road surface step is high (region G in Figure 6), first, the actuator drive selection device 42 calculates the control force of the suspension device 3 necessary to maintain the vehicle's posture based on the road surface shape information in front of the vehicle acquired by the forward sensor 41. Next, the actuator drive selection device 42 controls the changeover switch 55 so that the signal sent from the ride height adjustment actuator control unit 52 is connected to the ride height adjustment actuator 31a so that the control force due to the damping force of the active suspension 31 is 20% of the required control force of the suspension device 3. In addition, the actuator drive selection device 42 controls the changeover switch 65 so that the signal sent from the variable damper actuator control unit 62 is connected to the variable damper actuator 32a so that the control force due to the damping force of the damper 32 is 80% of the required control force of the suspension device 3.

[0063] Thus, when vehicle 1 is traveling on a road surface with a low step height and a high step frequency, as shown in Figure 7, the actuator drive selection device 42 sends signals to the changeover switches 55 and 65 to change the ratio in which the ride height adjustment actuator 31a is driven and the ratio in which the variable damper actuator 32a is driven, so that 100% of the control force required to absorb the unevenness of the road surface is the sum of the control force due to the damping force of the active suspension 31 and the control force due to the damping force of the damper 32.

[0064] In this way, by using the active suspension 31 and damper 32 in an appropriate ratio according to the shape of the road surface on which the vehicle 1 is traveling, it is possible to balance the advantages of both the active suspension 31, which is excellent at maintaining the vehicle's posture over high-height bumps, and the damper 32, which is excellent at suppressing vibrations over high-frequency bumps. Furthermore, since the active suspension 31 and damper 32 can be driven to generate the minimum control force necessary to maintain the vehicle's posture in response to bumps in the road surface, power consumption can be reduced.

[0065] [Third embodiment] Figure 8 is a block diagram showing the configuration of a suspension control device according to a third embodiment of the present invention.

[0066] In the third embodiment, as shown in Figure 8, we will describe the case where the damper 32 is a fixed damper with a constant damping force.

[0067] In the third embodiment, if the height of the step in the road surface located directly below the wheels 2 during travel, as estimated by the road surface shape estimation unit 43, is a height at which the vehicle body cannot maintain its posture with the fixed damper alone, the actuator drive selection device 42 controls the changeover switch 55 to connect the signal sent from the vehicle height adjustment actuator control unit 52 to the vehicle height adjustment actuator 31a. If the height of the step in the road surface estimated by the road surface shape estimation unit 43 is a height at which the vehicle body can maintain its posture with the fixed damper alone, the actuator drive selection device 42 controls the changeover switch 55 to disconnect the signal sent from the vehicle height adjustment actuator control unit 52 and fix the operation of the vehicle height adjustment actuator 31a.

[0068] In this way, the vehicle body is stabilized using only the braking force of the fixed dampers without normally driving the active suspension 31, and the active suspension 31 is driven only when necessary when driving on roads with high steps, thereby reducing power consumption.

[0069] In the embodiments described above, the suspension device 3 controlled by the suspension control device 4 was described as a suspension device mounted on a vehicle. However, the suspension control device and suspension control method according to this embodiment are not limited to this, and may also control suspension devices mounted on mobile bodies such as small mobility devices or delivery robots. It is clear from the claims that such modified or improved forms may also fall within the technical scope of the present invention. [Explanation of Symbols]

[0070] 1 Vehicle, 2 Wheels, 3 Suspension system, 4 Suspension control device, 5 Actuator control device, 31 Active suspension, 32 Damper, 41 Forward sensor, 42 Actuator drive selection device, 51 Unsprung weight sensor, 61 Sprung weight sensor.

Claims

1. A suspension control device that controls a suspension device attached to the wheels of a moving object, The suspension system comprises an active suspension system with adjustable ride height and a damper with adjustable damping force. A road surface shape measuring means for acquiring road surface shape, Actuator control means for controlling the drive of the suspension device, The system includes an actuator drive selection means that distributes the drive ratio between the active suspension and the damper based on information obtained by the road surface shape measuring means, The suspension control device is characterized in that the drive ratio defines the ratio of the active suspension to the ratio of the damper to the active suspension to drive the damper, and the sum of the control force of the active suspension to maintain the vehicle's posture and the control force of the damper to suppress vehicle vibrations becomes the control force necessary to absorb the unevenness of the road surface.

2. In the suspension control device according to claim 1, The suspension control device is characterized in that the road surface shape measuring means measures the height and frequency of irregularities on the road surface in front of the moving body.

3. In the suspension control device according to claim 2, The actuator drive selection means is characterized by determining the drive of the active suspension and the damper based on information acquired by the road surface shape measuring means and a pre-set correspondence between road surface step frequency and road surface step height.

4. In the suspension control device according to any one of claims 1 to 3, The actuator control means is A road surface frequency measuring means for measuring the height and frequency of road surface irregularities received by the aforementioned wheels, A suspension control device characterized by comprising: an attitude information acquisition means for measuring the inclination of the moving body.

5. A suspension control method for controlling a suspension device attached to the wheels of a moving object. There is, The suspension system comprises an active suspension system with adjustable ride height and a damper with adjustable damping force. A road surface shape measurement process to acquire the road surface shape, An actuator control step that controls the drive of the suspension device, The system includes an actuator drive selection step that distributes the drive ratio between the active suspension and the damper based on the information obtained by the road surface shape measurement step, The suspension control method is characterized in that the drive ratio defines the ratio of the active suspension to the ratio of the damper to the drive ratio, and the sum of the control force of the active suspension to maintain the vehicle's posture and the control force of the damper to suppress vehicle vibrations becomes the control force necessary to absorb the unevenness of the road surface.

6. In the suspension control method described in claim 5, The suspension control method is characterized in that the road surface shape measurement step measures the height and frequency of irregularities on the road surface in front of the moving body.

7. In the suspension control method according to claim 6, The actuator drive selection step is characterized by determining the drive of the active suspension and the damper based on the information obtained by the road surface shape measurement step and a pre-set correspondence between road surface step frequency and road surface step height.

8. In the suspension control method according to any one of claims 5 to 7, The actuator control process is as follows: A road surface frequency measurement step for measuring the frequency of the road surface irregularities received by the wheels, A suspension control method characterized by comprising a step of acquiring attitude information for measuring the attitude of the moving body.

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