Active suspension device and vehicle equipped with active suspension device

Abstract

Provided is an active suspension device capable of preventing deterioration of ride comfort of a person riding in a vehicle and a vehicle equipped with the active suspension device. The active suspension device (1) includes a preview sensor (3) that detects a road surface height in front of a wheel (16) and an ECU (24) that controls a stroke of a suspension to perform preview control. The ECU (24) includes a front wheel preview control section (241) that performs the preview control, a preview control success determination section (242) that determines whether the preview control is successful, and a rear wheel control section (243) that controls the stroke of a suspension of a rear wheel. The rear wheel control section (243) performs, in the case where the preview control of the front wheel is successful, the preview control and a skyhook control that controls the stroke of the suspension for the rear wheel, and in the case where the preview control of the front wheel fails, cancels the preview control for the rear wheel and performs the skyhook control.

Description

TECHNICAL FIELD

[0001] The present application relates to an active suspension device and a vehicle equipped with the active suspension device. BACKGROUND

[0002] In recent years, in a vehicle equipped with an electric suspension, a skyhook control is mainly configured, and ride comfort that cannot be achieved in a conventional suspension is achieved. In addition, in order to achieve a body vibration-free (body zero vibration) using an electric suspension, a preview control that detects a road surface unevenness and the like in advance by a sensor and controls the electric suspension using a result thereof is proposed.

[0003] By using the preview control, the electric suspension is able to perform a control that makes the body vibration zero.

[0004] Here, in the patent document 1, a control device of an active suspension that detects a displacement X of a road surface and an up-down acceleration of a body at a front end of the body and stores them in time series, infers a displacement of the road surface at a time when a vehicle passes through from the displacement X when detection of the displacement is normal, and controls actuators of front wheels and rear wheels according to the inferred displacement of the road surface, infers an up-down acceleration of a portion corresponding to the rear wheels of the body from the up-down acceleration when detection of the displacement is abnormal based on a wheel base and a vehicle speed, and controls the actuators of the rear wheels according to the inferred up-down acceleration is disclosed (see the abstract of the patent document 1).

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent document 1: Japanese Patent Application Laid-Open No. 5-96922 SUMMARY

[0008] In the control device of the active suspension disclosed in the patent document 1, the control mechanism judges whether the detection of the displacement by the road surface detection mechanism is normal, and when the judgment of the gist that the detection of the displacement is normal is made, the preview control is performed. On the other hand, when the judgment of the gist that the detection of the displacement is abnormal is made, the control mechanism does not perform the preview control but controls the actuators of the rear wheels using the up-down acceleration stored in the storage mechanism.

[0009] Here, in a case where the detection of the displacement is judged to be abnormal, the control section controls the actuators of the rear wheels using the up-down acceleration stored in the storage mechanism, and therefore, the vibration on the spring does not become zero, and there is a risk that the ride comfort of a person riding on the vehicle deteriorates.

[0010] In addition, in a case where the preview control cannot be properly applied to the front wheels due to the influence of disturbance and noise and the like, it is not preferable to apply the preview control to the rear wheels. Moreover, if the preview control is forced to operate in a situation where the preview control cannot be applied, it is also conceivable that the ride comfort of the person riding on the vehicle deteriorates.

[0011] The present application solves the above-described conventional problems, and aims to provide an active suspension device capable of preventing a risk of deterioration of the ride comfort of a person riding on a vehicle, and a vehicle equipped with the active suspension device.

[0012] The active suspension device of the present application is an active suspension device having a road surface state detection mechanism that detects a road surface height in front of a wheel, and a control unit that performs preview control of controlling a stroke of a suspension according to a displacement of the road surface height detected by the road surface state detection mechanism, characterized in that the control unit includes: a front wheel preview control unit that performs preview control of changing the stroke of the suspension of a front wheel according to the displacement of the road surface height detected by the road surface state detection mechanism; a determination unit that determines whether or not the preview control performed by the front wheel preview control unit of changing the stroke of the suspension of the front wheel and based on the control of the stroke is successful; and a rear wheel control unit that controls the stroke of a suspension of a corresponding rear wheel based on a result of the determination by the determination unit, the rear wheel control unit performing preview control of controlling the stroke of the suspension and ceiling control for the corresponding rear wheel in a case where the determination unit determines that the preview control of the front wheel is successful, and releasing the preview control and performing the ceiling control for the corresponding rear wheel in a case where the determination unit determines that the preview control of the front wheel is unsuccessful.

[0013] Effects of the Invention

[0014] According to the present application, it is possible to provide an active suspension device capable of preventing a risk of deterioration of the ride comfort of a person riding on a vehicle, and a vehicle equipped with the active suspension device. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic configuration view of a vehicle equipped with the suspension device of the embodiment of the present application.

[0016] Figure 2 is a schematic view of a suspension in the present embodiment.

[0017] Figure 3 is a configuration view of a vehicle equipped with the active suspension device of the present embodiment.

[0018] Figure 4 is a functional block diagram showing the functions of an ECU of the active suspension device in the present embodiment.

[0019] Figure 5 is a conceptual diagram illustrating load control of an ECU provided in an active suspension device that is an embodiment of the present application.

[0020] Figure 6 is a flowchart showing the operation of the active suspension device of the present embodiment.

[0021] Figure 7 (a) of is a conceptual diagram showing that the rear wheel control section of the ECU controls the rear wheel through the success-time processing section when the preview control of the front wheel is successful. Figure 7 (b) of is a conceptual diagram showing that the rear wheel control section of the ECU controls the rear wheel through the failure-time processing section when the preview control of the front wheel fails.

[0022] BRIEF DESCRIPTION OF REFERENCE NUMERALS

[0023] 1 active suspension device

[0024] 3 preview sensor (road surface state detecting mechanism)

[0025] 10 vehicle

[0026] 12 vehicle body

[0027] 14 front wheel tire

[0028] 16 wheel

[0029] 18 suspension arm

[0030] 20 spring

[0031] 22 shock absorber

[0032] 24 ECU

[0033] 241 front wheel preview control section

[0034] 242 preview control success determination section (determination section)

[0035] 243 rear wheel control section

[0036] 244 success-time processing section

[0037] 245 failure-time processing section

[0038] 251 information acquisition section

[0039] 252 first target load calculation section

[0040] 253 second target load calculation section

[0041] 254 combining section

[0042] 255 load control section

[0043] 256 Target Load Calculation Unit

[0044] 26 Wheel speed sensors

[0045] 29 Accelerometer

[0046] 54 Rear tires

[0047] 56 wheels

[0048] 100 road surface

[0049] 102, 104 protrusions Detailed Implementation

[0050] Next, refer to the appendix as appropriate. Figure 1 The embodiments of the present invention will be described in detail below. Figure 1 This is a schematic structural diagram of a vehicle equipped with a suspension device according to an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the suspension in this embodiment.

[0051] like Figure 1 and Figure 2 As shown, on the body 12 of the vehicle 10, there is a wheel 16 mounted on the front wheel tire 14 on each side, and a wheel 56 mounted on the rear wheel tire 54 on each side. The front wheels consist of the front wheel tire 14 and the wheel 16, and the rear wheels consist of the rear wheel tire 54 and the wheel 56. Furthermore, there are cases where the front wheels are shown as either the front wheel tire 14 or the wheel 16, and the rear wheels are shown as either the rear wheel tire 54 or the wheel 56.

[0052] Each wheel 16, 56 is suspended from the vehicle body 12 via a suspension consisting of suspension arms 18, springs 20, and variable damping shock absorbers 22 (hereinafter referred to as shock absorbers 22). The vehicle 10 is equipped with an ECU (Electronic Control Unit) 24 that performs various controls, and wheel speed sensors 26 located at each wheel that detect the wheel speed V of each wheel 16, 56. The wheel speed sensors 26 detect the rotational speed of each wheel 16, 56 as a detection signal (also called a wheel speed signal). In this embodiment, the ECU 24 changes (controls) the suspension travel by controlling the length of the shock absorber 22.

[0053] The ECU 24 (control unit) is configured by a microcomputer, a ROM, a RAM, a peripheral circuit, an input / output interface, various drivers, and the like. The ECU 24 is electrically connected to the shock absorber 22 and the wheel speed sensor 26 of each wheel 16, 56 via a communication line (in the present embodiment, a CAN (Controller Area Network) 28). In addition, the suspension device is configured by the ECU 24 and the wheel speed sensor 26. The ECU 24 realizes the front wheel preview control unit 241, the preview control success determination unit 242, and the rear wheel control unit 243 by executing a prescribed control program stored in the ROM.

[0054] Further, in the present embodiment, an electromagnetic shock absorber is described as an example, but the present embodiment is not limited thereto. That is, the present embodiment can also be applied to an air suspension and an active suspension using an active stabilizer. In addition, the vehicle 10 can be any one of a front-wheel drive vehicle, a rear-wheel drive vehicle, and a four-wheel drive vehicle.

[0055] In the present embodiment, the shock absorber 22 is configured by a single-tube (single-cylinder) shock absorber, for example. The shock absorber 22 houses a piston rod in a manner so as to be slidable in the axial direction with respect to a cylindrical cylinder filled with a Magneto-Rheological Fluid (MRF), and a piston installed at the front end of the piston rod divides the cylinder into an upper oil chamber and a lower oil chamber. A communication passage that communicates the upper oil chamber and the lower oil chamber is provided between the upper oil chamber and the lower oil chamber. An MLV coil is disposed inside the communication passage.

[0056] With respect to the shock absorber 22, the lower end of the cylinder is linked to the suspension arm 18 that is a wheel-side member, and the upper end of the piston rod is linked to a shock absorber bracket that is a vehicle body-side member, for example. As shown in FIG. 1, each shock absorber 22 links a sprung element (a movable element on the lower side of the suspension including the wheels 16, 56, knuckles, suspension arms 18, and the like) having a mass M1, and a sprung element (the vehicle body 12) having a mass M2 together with the spring 20. Figure 2

[0057] If a current is supplied from the ECU 24 to the not-shown MLV coil of the shock absorber 22, a magnetic field is applied to the MRF flowing through the communication passage, and the paramagnetic fine particles form a chain-like particle beam. Thus, the apparent viscosity (hereinafter, simply referred to as viscosity) of the MRF passing through the communication passage rises, and the damping force of the shock absorber 22 increases. Further, in the present embodiment, a single-tube shock absorber is adopted for the shock absorber 22, but other forms of shock absorbers can also be appropriately adopted.

[0058] ​Additionally, an acceleration sensor 29 is provided on the sprung element to detect the acceleration of the body 12 (spontaneous) along the travel direction of the shock absorber 22. When the acceleration sensor 29 detects the acceleration of the body 12 (spontaneous), the ECU 24 acquires the sprung acceleration. The ECU 24 acquires the sprung velocity by integrating the sprung acceleration over time with timing information. Furthermore, the acceleration sensor 29 can also acquire the unspontaneous acceleration of the unspontaneous element, and the ECU 24 can also acquire the unspontaneous velocity. Furthermore, the calculation of sprung velocity or unspontaneous velocity is not limited to time integration based on the ECU 24; for example, a gyroscope sensor can also be used to acquire it.

[0059] Additionally, vehicle 10 has a road surface 100 (refer to) in front of the front wheel tires 14 that provides access to the road surface in front of the vehicle (in front of vehicle 10). Figure 3 A predictive sensor (road surface condition detection mechanism) 3 detects the road surface condition of the front wheels 14. The predictive sensor 3 is positioned on the left and right sides, corresponding to the left and right front tires 14, respectively, and detects the height of the road surface in front of each wheel 16. The ECU 24 controls the suspension travel based on the change in road surface height detected by the predictive sensor 3, performing predictive control. In this embodiment, the predictive sensor 3 and the ECU 24 constitute the active suspension device 1.

[0060] Figure 3 This is a structural diagram showing a vehicle equipped with the active suspension device 1 of this embodiment. (As shown) Figure 3 As shown, the foresight sensor 3 detects the state (road condition) of the road surface 100 on the front side of the vehicle 10.

[0061] The foresight sensor 3 is mounted on the frame component F (i.e., on the body 12) at the front of the vehicle body 10, positioned forward of the front wheels 16 within the frame component F. As indicated by the white arrow, the foresight sensor 3 detects the condition of the road surface 100 directly in front of the front wheels 16. Furthermore, the foresight sensor 3 can be appropriately selected from radar, camera, laser, ultrasonic, and other types of sensors. Moreover, the foresight sensor 3 is not limited to a single sensor; it can be configured by combining multiple types of sensors, such as camera and laser sensors. Additionally, the foresight sensor 3 is positioned in front of each of the left and right front wheels 16.

[0062] Figure 4 This is a functional block diagram illustrating the function of the ECU24 of the active suspension device 1 in this embodiment.

[0063] The ECU 24 is configured to include a front wheel preview control section 241, a preview control success determination section 242 (determination section), and a rear wheel control section 243. The rear wheel control section 243 is configured to include a success time processing section 244 and a failure time processing section 245. The ECU 24 controls the stroke of the suspension (length of the shock absorber 22) of the corresponding wheel based on the displacement of the height of the road surface 100 detected by the preview sensor 3 (see Figure 3 ).

[0064] The front wheel preview control section 241 acquires the height of the road surface 100 in front of the wheel 16 of the corresponding front wheel from the preview sensor 3. The front wheel preview control section 241 changes the stroke of the suspension of the corresponding front wheel based on the displacement of the height of the road surface 100 detected by the preview sensor 3, thereby performing the preview control. The front wheel preview control section 241 adjusts the length of the shock absorber 22 of the corresponding front wheel, for example, based on the acquired height of the road surface 100.

[0065] That is, the front wheel on the right side in the vehicle 10 adjusts the length of the shock absorber 22 of the front wheel on the right side based on the height of the road surface 100 on the right side. On the other hand, the front wheel on the left side in the vehicle 10 adjusts the length of the shock absorber 22 of the front wheel on the left side based on the height of the road surface 100 on the left side.

[0066] The preview control success determination section 242 (determination section) determines whether the preview control of the stroke of the suspension by the front wheel preview control section 241 is successful.

[0067] As the determination of success (failure), the preview control success determination section 242 compares, for example, a theoretical vehicle model of the behavior assuming that the preview control of the front wheel is off and the actual body behavior. Thus, the preview control success determination section 242 determines that the preview control of the front wheel fails in a case where the value of the actual body behavior is worse than the value of the theoretical vehicle model. Specifically, in a case where the value of the acceleration sensor 29 at the time of passing over the break is equal to or more than a prescribed value, the preview control success determination section 242 can determine that the preview control fails.

[0068] Further, the preview control success determination section 242 is not limited to the comparison between the theoretical vehicle model and the actual body behavior. For example, in a case where the acceleration sensor 29 has an absolute value, the preview control success determination section 242 can determine that the preview control fails in a case where the absolute value is equal to or more than a prescribed threshold value of the acceleration sensor 29, and release (i.e., turn off) the preview control of the rear wheel.

[0069] The rear wheel control section 243 controls the stroke of the suspension of the corresponding rear wheel based on the determination result of the preview control success determination section 242. The rear wheel control section 243 controls the stroke of the suspension, for example, by adjusting the length of the shock absorber 22.

[0070] For example, in a case where the success of the preview control of the front wheels is judged by the preview control success judging section 242, the rear wheel control section 243 executes the preview control and the skyhook control on the corresponding rear wheels by the success time processing section 244.

[0071] On the other hand, in a case where the failure of the preview control of the front wheels is judged by the preview control success judging section 242, the rear wheel control section 243 cancels the preview control and executes the skyhook control on the corresponding rear wheels by the failure time processing section 245. Further, although the skyhook control is control that damps the vibration of the sprung element (the vehicle body 12) by actively adjusting the length of the shock absorber 22 based on the skyhook theory, the information of the preview sensor 3 is not used in the skyhook control.

[0072] As such, the ECU 24 of the active suspension device 1 of the present embodiment cancels the preview control and executes the skyhook control on the suspension of the corresponding rear wheels in a case where the preview control of the front wheels fails. That is, if the preview control fails in the front wheels, the possibility of failure is also high in the rear wheels, and in the present embodiment, the preview control in the rear wheels where the possibility of failure is high can be avoided.

[0073] Thus, the active suspension device 1 performs only the skyhook control in the rear wheels. Therefore, the risk that the ride comfort of the person riding on the vehicle deteriorates can be prevented. That is, since the preview control where the possibility of deterioration of the ride comfort is high can not be performed in the rear wheels, the deterioration of the ride comfort can be avoided.

[0074] In addition, the rear wheel control section 243 can increase (change) the gain of the skyhook control of the rear wheels in a case where the preview control of the front wheels succeeds, compared to the skyhook control of the rear wheels in a case where the preview control of the front wheels fails. That is, the rear wheel control section 243 can increase the weight of the skyhook control of the rear wheels in a case where the preview control of the front wheels succeeds.

[0075] Supplementarily, in a case where the preview control of the front wheels succeeds, the skyhook control is performed on the part that is not completely processed by the preview control, and thus the proportion of the skyhook control is less than that in a case where the preview control of the front wheels fails (the rear wheels are all skyhook control in a case where the preview control of the front wheels fails). Therefore, by increasing (changing) the gain of the skyhook control of the rear wheels in a case where the preview control of the front wheels succeeds, the required control amount can be output to the rear wheels. Here, the rear wheel control section 243 of the present embodiment is not limited to increasing the gain of the skyhook control of the rear wheels in a case where the preview control of the front wheels succeeds, compared to the skyhook control of the rear wheels in a case where the preview control of the front wheels fails, and for example, can be changed in a manner of decreasing the gain.

[0076] Further, the rear wheel control section 243 controls the stroke of the suspension of the rear wheel on the basis of the result of the judgment of the preview control of the corresponding front wheel for each of the rear wheels. Thus, the rear wheel control section 243 cancels the preview control for both of the left and right rear wheels and executes the skyhook control in the case where the preview control of the left and right front wheels fails. On the other hand, for example, in the case where the preview control of the right front wheel fails, the preview control of the right rear wheel is canceled and the skyhook control is executed for the right rear wheel.

[0077] As such, the active suspension device 1 of the present embodiment can execute the preview control in the front wheels and, in the case where the preview control fails, can execute the skyhook control for the corresponding rear wheels, and thus can prevent the risk of deterioration of the ride comfort of the person riding on the vehicle.

[0078] Next, the load control involved in the preview control and the skyhook control will be described.

[0079] <ECU LOAD CONTROL>

[0080] Figure 5 is a diagram for explaining the load control of the ECU 24 provided in the active suspension device 1 of the embodiment of the present application. Further, the load control of the ECU 24 is one example of the function of the ECU 24 of the active suspension device 1 shown in Figure 4 is not limited thereto.

[0081] Figure 5 The ECU 24 shown in is configured to include an information acquisition section 251, a target load calculation section 256, and a load control section 255. In addition, the target load calculation section 256 is configured to include a first target load calculation section 252, a second target load calculation section 253, and a unification section 254.

[0082] The information acquisition section 251 acquires information on the height of the road surface 100 (relative road surface height) as time-series information on the road surface state related to the running road surface in the advancing direction of the vehicle 10. The information on the relative road surface height is, for example, detected by the preview sensor 3 on the relative road surface height of the vehicle 10. Further, the relative road surface height indicates the relative height of the sprung element (vehicle body 12) with respect to the road surface 100.

[0083] In addition, as one example, the information acquisition section 251 acquires time-series information on the sprung acceleration and the unsprung acceleration, respectively. The information on the sprung acceleration is acquired on the basis of the detection value of the acceleration sensor 29 provided on the sprung element (vehicle body 12) of the vehicle 10. In addition, the information on the unsprung acceleration is acquired on the basis of the detection value of the acceleration sensor (not shown) provided on the unsprung element of the vehicle 10. Further, since the unsprung acceleration is an arbitrary structural element, the information acquisition section 251 is not particularly limited whether or not to acquire the unsprung acceleration.

[0084] The information acquisition unit 251 estimates the "suspension-up speed" and the "absolute road surface height" based on the acquired height of the road surface 100 (relative road surface height), the suspension-up acceleration, and the suspension-down acceleration. For example, the information acquisition unit 251 estimates the "suspension-up speed" as the current vehicle state. In addition, the "absolute road surface height" indicates the absolute height of the suspension-up element (vehicle body 12) with respect to the road surface 100.

[0085] In this case, the information acquisition unit 251 estimates the "absolute road surface height" obtained by subtracting an error amount included in the relative road surface height along with the vehicle body vibration from the relative road surface height, for example, based on the time-series information of each of the suspension-up acceleration, the suspension-down acceleration, and the height of the road surface 100 (relative road surface height). In addition, the information acquisition unit 251 can also directly acquire the "suspension-up speed" and the "suspension-down speed" from the gyro sensor by using the gyro sensor.

[0086] The information of the "suspension-up speed" (vehicle state amount) estimated by the information acquisition unit 251 is sent to the 1st target load calculation unit 252. On the other hand, the information of the "absolute road surface height" estimated by the information acquisition unit 251 is sent to the 2nd target load calculation unit 253.

[0087] Next, the target load calculation unit 256 calculates the integrated target load, which is the target value of the attenuation operation and the extension / contraction operation of the shock absorber 22, by arithmetic operation based on various kinds of information acquired by the information acquisition unit 251.

[0088] The 1st target load calculation unit 252 of the target load calculation unit 256 calculates the 1st target load involved in the skyhook control based on the "suspension-up speed" (vehicle state amount) estimated by the information acquisition unit 251. Specifically, for example, the 1st target load calculation unit 252 calculates the 1st target load by multiplying the estimated "suspension-up speed" (vehicle state amount) by a skyhook attenuation coefficient using a control rule based on the skyhook theory. The 1st target load calculated by the 1st target load calculation unit 252 is sent to the integration unit 254. In addition, in the case where it is determined that the preview control of the front wheels is successful in the skyhook control of the rear wheels, the target load calculation unit 256 can also calculate by further multiplying the 1st target load by a gain, thereby changing the gain of the skyhook control.

[0089] The second target load calculating section 253 of the target load calculating section 256 calculates the second target load involved in the preview control, based on the "absolute road surface height" (actual road surface height) estimated by the information acquiring section 251. Specifically, for example, the second target load calculating section 253 calculates the second target load by multiplying the "absolute road surface height" (actual road surface height) by a preview control gain, using a control law based on the skyhook theory. The second target load calculated by the second target load calculating section 253 is sent to the integrating section 254.

[0090] The integrating section 254 of the target load calculating section 256 performs integration of adding together the first target load calculated by the first target load calculating section 252 and the second target load calculated by the second target load calculating section 253. The information of the integrated target load after integration by the integrating section 254 is sent to the load control section 255.

[0091] The load control section 255 calculates a target current value that enables achievement of the integrated target load calculated by the target load calculating section 256. The load control section 255 performs drive control of the electric motor possessed by each of the plurality of shock absorbers 22, for example, in such a manner that the motor current involved in the electric motor (not shown) follows the calculated target current value. By performing drive control of the electric motor in this way, it is possible to adjust the length of the corresponding shock absorber 22, and control the stroke of the corresponding suspension.

[0092]

[0093] Next, the operation of the active suspension device 1 of the present embodiment will be described. Figure 6 is a flowchart showing the operation of the active suspension device 1 of the present embodiment. The description will be given while referring to Figures 1 to 4 together.

[0094] First, the preview sensor 3 detects the height of the road surface 100 ahead of the front wheels (wheels 16) in the vehicle 10 during travel (step Sll).

[0095] The front wheel preview control section 241 of the ECU 24 acquires the height of the road surface 100 ahead of the front wheels from the preview sensor 3. The front wheel preview control section 241 changes the stroke of the suspension of the front wheels in accordance with the displacement of the height of the road surface 100 detected by the preview sensor 3, and executes preview control (step S12).

[0096] ​The front wheel preview control section 241 adjusts the length of the shock absorber 22 of the corresponding wheel 16, for example, in accordance with the height of the road surface 100 that is acquired. In this case, the right wheel 16 in the vehicle 10 adjusts the length of the shock absorber 22 of the right wheel 16 in accordance with the height of the right road surface 100. On the other hand, the left wheel 16 in the vehicle 10 adjusts the length of the shock absorber 22 of the left wheel 16 in accordance with the height of the left road surface 100.

[0097] The preview control success determination section 242 determines whether the preview control that controls the stroke of the suspension by changing the length of the shock absorber 22 of the front wheel 16 (the stroke of the suspension) is successful (fails) (step S13).

[0098] The preview control success determination section 242 compares, for example, a theoretical vehicle model that assumes the behavior in the case where the preview control of the wheel 16 is turned off and the actual vehicle body behavior. The preview control success determination section 242 determines that the preview control of the wheel 16 fails in the case where the value of the actual vehicle body behavior is worse than the value of the theoretical vehicle model. Specifically, in the case where the value of the acceleration sensor 29 at the time of passing over the break is equal to or more than a prescribed value, the preview control success determination section 242 determines that the preview control fails.

[0099] Furthermore, the preview control success determination section 242 is not limited to the comparison between the theoretical vehicle model and the actual vehicle body behavior. For example, in the case where the acceleration sensor 29 has an absolute value, the preview control success determination section 242 determines that the preview control fails in the case where the absolute value is equal to or more than a prescribed threshold value of the acceleration sensor 29, and cancels (i.e., turns off) the preview control of the rear wheel.

[0100] In the case where the preview control of the wheel 16 is determined to be successful by the preview control success determination section 242 (YES in step S13), the rear wheel control section 243 executes the preview control that adjusts the length of the shock absorber 22 and the skyhook control on the corresponding rear wheel by the success-time processing section 244 (step S14).

[0101] On the other hand, in the case where the preview control of the wheel 16 is determined to fail by the preview control success determination section 242 (NO in step S13), the rear wheel control section 243 cancels the preview control and executes the skyhook control on the corresponding rear wheel by the failure-time processing section 245 (step S15).

[0102] As such, the ECU 24 of the active suspension device 1 of the present embodiment cancels the preview control of the suspension of the rear wheel and executes the skyhook control in the case where the preview control of the front wheel fails. Thus, the active suspension device 1 can make the sprung vibration zero by the skyhook control, and thus can prevent the risk that the ride comfort of the person who rides in the vehicle 10 deteriorates.

[0103] Effects of the Embodiments

[0104] Figure 7 (a) of FIG. 10 is an explanatory view showing the concept that the rear wheel control section 243 of the ECU 24 controls the rear wheel through the success-time processing section 244 when the preview control of the front wheel is successful. Figure 7 (b) of FIG. 10 is an explanatory view showing the concept that the rear wheel control section 243 of the ECU 24 controls the rear wheel through the failure-time processing section 245 when the preview control of the front wheel fails.

[0105] The ECU 24 judges whether the preview control in the front wheel is successful or failed after the preview control is performed on the front wheel, by the preview control success judging section 242. The rear wheel control section 243 controls the stroke of the suspension of the rear wheel corresponding to the front wheel, based on the result of the judgment by the preview control success judging section 242.

[0106] As shown in (a) of FIG. 10, in the case where the preview control of the right front wheel tire 14 is judged to be successful by the preview control success judging section 242, the rear wheel control section 243 performs the preview control and the skyhook control that control the stroke of the suspension, on the rear wheel (the rear wheel tire 54) on the same side as the front wheel, i.e., the right side, through the success-time processing section 244. Figure 7 In the left side view of (a) of FIG. 10, after the right front wheel tire 14 passes over the protrusion 104, the preview control success judging section 242 shows that the preview control of the front wheel preview control section 241 is successful. As a result of the successful preview control, in the right side view of (a) of FIG. 10, the rear wheel control section 243 performs the preview control and the skyhook control on the right rear wheel (the rear wheel tire 54) through the success-time processing section 244.

[0107] Figure 7 On the other hand, as shown in (b) of FIG. 10, in the case where the preview control of the right front wheel tire 14 is judged to be failed by the preview control success judging section 242, the rear wheel control section 243 cancels the preview control and performs the skyhook control on the right rear wheel (the rear wheel tire 54) through the failure-time processing section 245. Figure 7 In the left side view of (b) of FIG. 10, after the right front wheel tire 14 passes over the protrusion 104, the preview control success judging section 242 shows that the preview control of the front wheel preview control section 241 is failed. As a result of the failed preview control, in the right side view of (b) of FIG. 10, the rear wheel control section 243 cancels the preview control and performs the skyhook control on the right rear wheel (the rear wheel tire 54) through the failure-time processing section 245.

[0108] Figure 7

[0109] In the left side view of (b) of FIG. 10, after the right front wheel tire 14 passes over the protrusion 104, the preview control success judging section 242 shows that the preview control of the front wheel preview control section 241 is failed. As a result of the failed preview control, in the right side view of (b) of FIG. 10, the rear wheel control section 243 cancels the preview control and performs the skyhook control on the right rear wheel (the rear wheel tire 54) through the failure-time processing section 245. Figure 7 Figure 7 ​​​​In the graph on the right side of (b), the rear wheel control section 243 cancels the preview control on the rear wheel (the rear wheel tire 54) on the same side as the front wheel, i.e., the right side, by the failure-time processing section 245, and executes the skyhook control.

[0110] The rear wheel control section 243 can execute the skyhook control by the failure-time processing section 245, and execute the conventional suspension control, i.e., the suspension control of only the skyhook control without the preview control. Thus, the ECU 24 can absorb the vibration generated in the rear wheel tire 54 on the right side. Further, the failure of the preview control of the front wheel occurs, for example, in a case where the protrusion 104 or the like is not detected.

[0111] Further, as described above, the rear wheel control section 243 can increase the gain of the skyhook control of the rear wheel tire 54 in the case where the preview control of the front wheel tire 14 is successful, as compared with the case where the preview control of the front wheel tire 14 is failed. Like this, by increasing the gain of the skyhook control of the rear wheel at the time of success, the shock absorber 22 of the rear wheel tire 54 can output the required control amount, and can absorb the vibration of the vehicle 10, as compared with the case where the gain is not increased.

[0112] As described above, the active suspension device 1 of the first embodiment is configured to include the preview sensor 3 and the ECU 24. The ECU 24 is configured to include the front wheel preview control section 241, the preview control success determination section 242, and the rear wheel control section 243.

[0113] The rear wheel control section 243 executes the preview control and the skyhook control of the stroke of the suspension for the corresponding rear wheel by the success-time processing section 244 in the case where the preview control of the front wheel is determined to be successful by the preview control success determination section 242. On the other hand, in the case where the preview control of the front wheel is determined to be failed by the preview control success determination section 242, the rear wheel control section 243 cancels the preview control for the corresponding rear wheel by the failure-time processing section 245, and executes the skyhook control.

[0114] Thus, the active suspension device 1 of the first embodiment can prevent the risk of deterioration of the ride comfort of the person riding on the vehicle 10 even in the case where the preview control of the front wheel is determined to be failed by the preview control success determination section 242.

[0115] Further, in the present embodiment, although the preview control based on the front wheel preview control section 241 is determined in the preview control success determination section 242, the determination of the preview control is not particularly limited to the above.

[0116] For example, if the foresight sensor 3 detects an object such as a plastic bag or a plastic bottle and detects the height of the road surface 100, the front wheel foresight control section 241 changes the length of the shock absorber 22 (suspension stroke) of the front wheel based on the height of the object such as the plastic bag or the plastic bottle. In this case, if the front wheel tire 14 runs over the object such as the plastic bag or the plastic bottle, the object deforms, and thus the height of the road surface 100 detected by the foresight sensor 3 becomes a false detection.

[0117] The embodiment of the present application can also determine that the foresight control has failed in this case. That is, if the foresight sensor 3 falsely detects the height of the road surface 100 due to an object such as a plastic bag or a plastic bottle, the object deforms and the length of the shock absorber 22 of the front wheel becomes an inappropriate length, and thus the sprung acceleration of the sprung element of the vehicle body 12 or the unsprung acceleration of the unsprung element changes.

[0118] Therefore, the foresight control success determination section 242 can finely perform the determination of whether the foresight control has succeeded by setting the prescribed threshold value of the acceleration sensor relatively low. Thus, even if the height of the road surface 100 is falsely detected due to an object such as a plastic bag or a plastic bottle, the rear wheel control section 243 can perform only the ceiling control on the rear wheel tire 54 by the failure-time processing section 245.

Claims

1. An active suspension device, comprising: A road condition detection mechanism for measuring the road surface height in front of the wheels; and The control unit performs predictive control by controlling the suspension travel based on the displacement of the road surface height detected by the road surface condition detection mechanism. The active suspension device is characterized in that... The control unit includes: The front wheel anticipatory control unit performs anticipatory control by changing the travel of the front wheel suspension based on the displacement of the road surface height detected by the road surface condition detection mechanism. The judgment unit determines whether the predictive control executed based on the change in suspension travel of the front wheels by the front wheel predictive control unit is successful; and The rear wheel control unit controls the suspension travel of the corresponding rear wheel based on the judgment result of the judgment unit. When the judgment unit determines that the front wheel anticipation control has been successful, the rear wheel control unit performs anticipation control of the suspension travel and roof control for the corresponding rear wheel. If the determination unit determines that the predictive control of the front wheel has failed, the predictive control for the corresponding rear wheel is released, and the ceiling control is executed.

2. The active suspension device as described in claim 1, characterized in that, The rear wheel control unit adjusts the gain of the rear wheel suspension control when the front wheel anticipation control is successful, compared to the rear wheel suspension control when the front wheel anticipation control fails.

3. The active suspension device as described in claim 1 or 2, characterized in that, The judgment unit compares the theoretical vehicle model and the actual vehicle body movement under the assumption that the predictive control of the front wheels is off. If the value of the actual vehicle body movement deteriorates compared with the value of the theoretical vehicle model, it determines that the predictive control of the front wheels has failed.

4. The active suspension device as described in claim 3, characterized in that, It also includes a sensor for detecting the acceleration of the vehicle body along the travel direction of the suspension of the front wheels. If the sensor value exceeds a predetermined value when crossing a steep slope, the judgment unit determines that the predictive control of the front wheels has failed.

5. A vehicle, characterized in that, It has an active suspension device as described in any one of claims 1 to 4.

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