JPH0641845Y2 - Active suspension system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an active suspension device, and in particular, a suspension for controlling relative displacement between a vehicle body and wheels is provided, and suspension control is performed during traveling. The present invention relates to an active suspension device that suspends suspension control while the vehicle is stopped.

[Conventional technology]

An example of the active suspension device is described in Japanese Patent Application No. 62-60591 previously proposed by the present applicant.

The device according to this prior application has a vehicle speed detecting means including a vehicle speed sensor for detecting a vehicle speed, and adjusts a changeable gain for performing roll control based on a vehicle speed value by the vehicle speed detecting means, thereby stopping the vehicle. It is designed to avoid self-excited vibration in the lateral direction of the vehicle during high speed or extremely low speed running. In particular, when the vehicle speed is zero, the gain is set to zero so that the roll control is not performed.

[Problems to be solved by the device]

However, in the technique described in the above-mentioned prior application, since the vehicle speed sensor for detecting the vehicle speed is separately mounted, for example, the detection value of the vehicle speed sensor becomes zero due to a disconnection during traveling. If such an abnormal situation occurs, the control device will mistakenly judge that the vehicle has stopped and will immediately stop the roll control, so if such a situation occurs during turning, the vehicle will be in a rolled state. There was an unsolved problem that not only the passengers felt uneasy, such as being forced to run in the car, but also the stable running was not possible.

Therefore, the present invention has been made in view of such an unsolved problem, and a plurality of vehicle speed sensors for detecting a vehicle speed are mounted to form a redundant system thereof, and the detection of the plurality of vehicle speed sensors is performed. If any of the sensors is determined to be faulty by the value, the highest value of these detected values is forcibly set as the vehicle speed value, and suspension control is performed according to this vehicle speed value. Therefore, solving the above-mentioned unsolved problems is an issue to be solved.

[Means for Solving the Problems]

Therefore, in order to solve the above-mentioned problems, the present invention provides a first
As shown in the basic configuration diagram of the drawing, a suspension for controlling the relative displacement between the vehicle body and the wheels according to a changeable command value, and an attitude change detecting means for detecting attitude change information according to the attitude change of the vehicle body are provided. In the active suspension device configured to change and control the command value based on the posture change information, a vehicle speed detecting means including a plurality of vehicle speed sensors, and one of the vehicle speed sensors based on the detection values of the vehicle speed detecting means Failure determination means for determining whether or not a failure state,
When the determination result of the failure determination means is not in the failure state, the detection value by the vehicle speed detection means is set as the vehicle speed value,
Further, when the judgment result is a failure state, a vehicle speed setting means for forcibly setting the highest value as the vehicle speed value among the detection values by the plurality of vehicle speed sensors, and the vehicle speed value set by this vehicle speed setting means. Based on the driving state determination means for determining whether the vehicle is in the traveling state or the stopped state, and when the driving state determination means determines that the vehicle is in the traveling state, the command value is changed and controlled according to the posture change information. And a command value control means for stopping the control of the command value when it is determined that the vehicle is stopped.

[Operation] In this invention, the attitude change information is detected by the attitude change detecting means on the vehicle body, while the vehicle speed is detected by the vehicle speed detecting means. Based on the detected value, the failure determining means determines whether or not the vehicle speed sensor is in a failure state. To be judged. Accordingly, when it is determined that each vehicle speed sensor is in the normal state, the vehicle speed setting means sets the detection value of the vehicle speed detection means as the vehicle speed value as it is, and the driving state determination means determines the vehicle speed based on the set vehicle speed value. It is determined whether the vehicle is running or stopped. And
When it is determined that the vehicle is in the running state, the command value control means changes and controls the command value for operating the suspension according to the detected attitude change information, and the vehicle is in the stopped state. If it is determined that the control of the command value is stopped.

On the other hand, when one of the vehicle speed sensors is determined to be in a failure state by the failure determination means, the vehicle speed setting means sets the highest value among the vehicle speed sensors as the vehicle speed value to be provided to the driving state determination means. Then, the driving state determination means determines whether the vehicle is in the stopped state or the traveling state based on the forcibly set vehicle speed value, and the command value control means operates in the same manner as described above.
Therefore, among a plurality of vehicle speed sensors, the probability that all of them will fail at one time is low, and even if a part of them fails, it is complemented by the detection values of other normally operating sensors.
Compared with the case where the sensor is mounted alone, the possibility of erroneous determination of the driving state is significantly reduced, and the suspension control is accurately performed.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

2 to 6 are views showing an embodiment of the present invention. This embodiment shows the case of roll control.

First, in FIG. 2, 10 indicates a vehicle body side member, and 11FL to
11RR indicates front left to rear right wheels, and 12 indicates an active suspension device.

The active suspension device 12 includes hydraulic suspensions 14FL to 11FL to 11RR which are individually provided for the wheels 11FL to 11RR.
14RR and hydraulic source for this suspension 14FL-14RR
16, accumulators 18 and 18 for accumulating pressure, which are interposed between the hydraulic power source 16 and suspensions 14FL to 14RR, first and second vehicle speed sensors 19A and 19B for detecting vehicle speed, and a lateral acceleration sensor 2
0, and a controller 22 that individually controls the suspensions 14FL to 14RR according to the detection value of the lateral acceleration sensor 20,
The vehicle speed sensor 19A (or 1
9B) has an alarm device 23 for alarming the failure.

Among these, each of the suspensions 14FL to 14RR is a hydraulic cylinder 26FL to 26 as a fluid pressure cylinder interposed between the vehicle body side member 10 and each wheel side member 24 of the wheels 11FL to 11RR.
RR and pressure control valves 28FL to 28RR for adjusting the operating hydraulic pressures of the hydraulic cylinders 26FL to 26RR, respectively.
Further, each of pressure chambers L of the hydraulic cylinders 26FL to 26RR, which will be described later, is connected to a vibration absorbing accumulator 34 via a throttle valve 32 as shown in the drawing. Further, a coil spring 36, which has a relatively low spring constant and supports a static load of the vehicle body, is disposed between the vehicle body and the wheels of each of the hydraulic cylinders 26FL to 26RR.

Each of the hydraulic cylinders 26FL to 26RR is a cylinder tube.
26a, and this cylinder tube 26a has a piston 26
A lower pressure chamber L separated by c is formed.
The lower end of the cylinder tube 26a is attached to the wheel side member 24, and the upper end of the piston rod 26b is attached to the vehicle body side member 1.
It is attached to 0. In addition, the pressure chamber L is the hydraulic pipe 3
The hydraulic pressure in the pressure chamber L can be controlled by communicating with the output ports of the pressure control valves 28FL to 28RR via 8. Here, 52 and 54 are pipes for sending and returning hydraulic fluid between the hydraulic power source 16 and the pressure control valves 28FL to 28RR.

Further, each of the pressure control valves 28FL to 28RR is formed by a pilot type proportional electromagnetic pressure reducing valve having a spool valve housed in a cylindrical valve housing and a proportional solenoid integrally provided with the spool valve. Then, by adjusting the value of the control current I as a command value to be supplied to the exciting coil of the proportional solenoid, the hydraulic cylinder 26FL is output from the output port.
The control pressure P _C output to (to 26 RR) can be adjusted as shown in FIG. That is, the control current I is controlled pressure P _C is the neutral pressure P _CN, and the control current I is the maximum value I _MAX direction to an increase or a minimum value I _MIN direction thereof than the neutral value I _N when the neutral value I _N When reduced to provide the control pressure P _C in proportion to the value I. Here, P _CMAX is the saturated output pressure of the hydraulic power source 16.

On the other hand, of the first and second vehicle speed sensors 19A and 19B, the first vehicle speed sensor 19A is at a position where the rotation speed of the axle can be detected, and the second vehicle speed sensor 19B is at a position where the rotation speed of the output shaft of the transmission can be detected. Is equipped with each. These first and second vehicle speed sensors
Both 19A and 19B are formed by an optical method, and the vehicle speed signals D1 and D2, which are pulse signals with a cycle corresponding to the number of revolutions, are supplied to the controller 2
It is designed to output to 2.

Further, the lateral acceleration sensor 20 described above is installed at a predetermined position slightly ahead of the center of gravity of the vehicle. The lateral acceleration sensor 20 detects the lateral acceleration G _Y generated in the vehicle body and outputs a lateral acceleration signal g _Y, which is an analog voltage signal proportional thereto, to the controller 22. In other words, the lateral acceleration signal g _Y, as shown in FIG. 4, a predetermined positive neutral value g _YN next when the lateral acceleration G _Y is zero, positive lateral acceleration + G _Y
It is set to increase from the neutral value g _YN when occurs, and decrease from the neutral value g _YN when a negative lateral acceleration −G _Y occurs. Here, the lateral acceleration G _Y that acts when the vehicle turns right is positive, and the lateral acceleration G _Y that acts when the vehicle turns left is
Is negative.

Further, as shown in FIG. 5, the controller 22 includes a microcomputer 70 and a microcomputer 70 for converting an input lateral acceleration signal g _Y into a digital amount.
A / D converter 71 for output to 70 and microcomputer 70
D / A converters 73A to 73D that convert the digital control signal SC output from the D / A converters 73A to 73D
Of the control current I according to the output of the pressure control valves 28FL to 28RR.
And driving circuits 74A to 74D for individually outputting to

Among them, the microcomputer 70 is configured to include at least an interface circuit 76, an arithmetic processing unit 78, and a storage device 80 including RAM, ROM and the like, and the interface circuit 76 is formed to include an I / O port and the like. . Further, the arithmetic processing unit 78 reads the lateral acceleration signal g _Y and the vehicle speed signals D1 and D2 via the interface circuit 76, and based on these, performs arithmetic processing and other processing shown in FIG. 6 described later. The storage device 80 stores in advance a predetermined program and fixed data necessary for executing the processing of the arithmetic processing device 78, and can store the processing result of the arithmetic processing device 78.

The alarm device 23 is composed of an LED, and the microcomputer 7
Connected to 0.

Next, the operation of the above embodiment will be described.

When the vehicle ignition switch is turned on, the controller 22 is also turned on and the microcomputer
The 70 executes the processing of a predetermined main program and interrupts every predetermined time (for example, 20 msec), and the sixth
The processing shown in the figure is executed.

First, in the step of FIG. 6, the arithmetic processing unit 78 of the microcomputer 70 determines that the vehicle speed signal is a pulse signal.
Read v1 and v2 respectively and move to step. In step, the vehicle speeds V1 and V2 are respectively calculated by calculating the number of pulses or the pulse interval per unit time of the read vehicle speed signals v1 and v2, and these are temporarily stored.

Next, in step, for checking vehicle speed sensors 19A, 19B for vehicle speeds V1, V2, | V1-V2 |> α
Determine whether or not. Where α is the vehicle speed sensor 19A, 19B
With respect to the variation in the detected value of 1), one of the detected values becomes zero, for example, and the predetermined vehicle speed value is set so that normality or abnormality (failure) can be discriminated. If | V1−V2 | ≦ α is judged in this step, both sensors 19A, 19A
The difference between the detected values of B is due to mere variation and there is no great difference, and it is determined that both are operating normally, and the process proceeds to steps 1 to.

First, in step, the average value V _AV of the vehicle speeds V1 and V2 is calculated,
In step, the average value V _AV is set to the vehicle speed value V. Next, in step, it is determined whether the vehicle speed value V is zero, and if it is not zero, it is determined that the vehicle is traveling, and the roll control in steps 1 to 3 is performed.

That is, the arithmetic processing device 78 reads the lateral acceleration signal g _Y in step, and refers to the storage table in step to set the lateral acceleration G _Y according to the lateral acceleration signal g _Y. Next, in step, the control current I is changed to I = G _Y · K _Y
(K _Y is a predetermined gain constant), and in step, the control signal SC corresponding to the calculated control current I is individually output to the D / A converters 73A to 73D, and the process returns to the main program.

Further, when it is determined that V = 0 in the above step, it is determined that the vehicle is stopped, and in order to avoid self-excited vibration of the roll and the like, the process returns to the main program without performing steps 1 to 3.

On the other hand, when it is determined that | V1-V2 |> α in the above step, one of the first and second vehicle speed sensors 19A and 19B has a failure such as disconnection, and the detected value v1 (or v2) becomes zero, and the absolute value of the difference value | V1-V2 | exceeds the reference value α. Therefore, the process immediately shifts to the step, and after instructing the alarm device 23 to issue the warning of the vehicle speed sensor failure, the process shifts to the steps 1 to.

In step, to compare the magnitude of vehicle speed value, | V1 |
> | V2 | If | V1 |> | V2 |, the process proceeds to step and the vehicle speed value V is set to the first vehicle speed sensor 19
If the value V1 applied to A is set, and if | V1 | ≦ | V2 |, go to step and set the value V2 applied to the second vehicle speed sensor 19B to the vehicle speed value V, and thereafter, in any case It is attached to the processing of the steps 1 to 3 described above. As a result, while the vehicle is traveling, the first vehicle speed sensor 19A may be out of order and the vehicle speed value V
When 1 is zero, the vehicle speed value V2 applied to the second vehicle speed sensor 19B is forcibly set to the vehicle speed value V. On the contrary, the second vehicle speed sensor
When 19B is out of order, the vehicle speed value V1 is set to the vehicle speed value V.

By the way, as described above, the control signals SC, ..., SC output in the step are individually converted into analog amounts by the D / A converters 73A to 73D, and then output to the drive circuits 74A to 74D. Then, the drive currents 74A to 74D supply the front left to rear right pressure control valves 28FL to 28RR with the control current I having the values set in steps as described above.

Next, the overall operation will be described for the case where both the first and second vehicle speed sensors 19A and 19B are normal.

When the vehicle is stopped, the vehicle speed value V = 0 in the step of FIG. 6 described above.
Roll rigidity control is not performed. Therefore, the self-excited vibration of the roll control does not occur.

Further, when the vehicle is running at a constant load on a flat, good road with a rated load, the lateral acceleration G _Y generated in the vehicle is zero. At this time, the control current I which is set through the processing of steps - in FIG. 6 described above becomes almost its neutral value I _N. Therefore, the control pressure P _C output by the pressure control valves 28FL to 28RR, that is, the pressure in the pressure chamber L of the hydraulic cylinders 26FL to 26RR becomes substantially the neutral value P _CN . This makes suspension 14FL ~ 1
In 4RR, the neutral state is maintained and the vehicle height value is properly maintained.

On the other hand, the vehicle turns right, for example, and a positive lateral acceleration occurs,
It is assumed that the vehicle rolls so that the left side of the vehicle sinks when viewed from the rear side of the vehicle. In this state, the control current I set by the above-mentioned processing of FIG. 6 is the pressure control valve 28FL, 2 on the outer wheel side.
The control pressure P _C output by 8RL rises above the neutral pressure P _CN , and that of the inner ring side pressure control valves 28FR, 28RR decreases below the neutral pressure P _CN . As a result, the hydraulic cylinders 26FL, 26RL on the outer wheel side generate a biasing force against the sinking of the vehicle body, and the hydraulic cylinders 26FR, 26RR on the inner wheel side do not promote lifting of the vehicle body, and The change in posture is accurately suppressed and controlled. This is the same when the vehicle turns left.

Next, it is assumed that one of the first and second vehicle speed sensors 19A and 19B (probably the sensor 19A) has an abnormality such as a disconnection. In this case, the detected value V1 becomes zero and is processed through steps ~, ~ and ~ in Fig. 6, so that the second vehicle speed sensor 19B is operating normally at the vehicle speed value V.
The value V2 that is applied to is set. Therefore, the arithmetic processing device
78 is designed so that if one sensor 19A fails, the other sensor 19B
The vehicle state is accurately determined to be the traveling state by being supplemented by the detection value of. That is, the roll control (steps from FIG. 6) is not interrupted without the operating state being erroneously determined as in the unsolved problem described above.

As described above, in this embodiment, the two vehicle speed sensors 19A and 19B are used.
Since the vehicle speed detection system is made redundant by using, the possibility that both sensors 19A and 19B will fail at the same time is extremely reduced. As a result, even if the above-mentioned sensor abnormality occurs during turning, for example, roll control is reliably performed based on the vehicle speed that is set as an alternative, and sudden roll change is not only eliminated but continuous roll control is performed. Therefore, the fail-safe function that the anxiety given to the passengers is eliminated is exhibited.
Further, in the present embodiment, since an alarm is issued immediately when a situation related to the vehicle speed sensor abnormality occurs, maintenance becomes easy.

Here, the lateral acceleration sensor 20, the A / D converter 71 and the steps of FIG. 6 form the attitude change detecting means, and the first and second vehicle speed sensors 19A and 19B and the steps of FIG. The vehicle speed detecting means is formed by the steps, the failure determining means is formed by the processing of the steps in the figure, the vehicle speed setting means is formed by the steps of, and the driving state determining means by the steps of the figures. Is formed, and the processing of steps in FIG.
Command value control means is formed by the D / A converters 73A to 73D and the drive circuits 74A to 74D.

In addition, in the above-mentioned embodiment, the case of the roll rigidity control which is assumed to cause the greatest hindrance to traveling if the posture change suppression control is neglected has been described, but the present invention is not necessarily limited to this, for example, , The longitudinal stiffness is detected to control the pitch rigidity, the vertical acceleration is detected to perform the bounce damping control, or the relative displacement between the vehicle body and the wheels is used to perform the suppression control. May be controlled by appropriately combining the above.

Further, the number of vehicle speed sensors included in the vehicle speed detecting means is not necessarily limited to two in the above-described embodiment, and may be three or more in some cases.

Further, in the processing of the step of FIG. 6 which constitutes the above-mentioned failure judging means, the average value of the individual vehicle speeds is obtained, and the difference between this average value and the detection value of each sensor is calculated, and this difference value is predetermined. Abnormalities such as a wire breakage of the vehicle speed sensor and a large detection error may be determined depending on whether or not the value exceeds the value.

Furthermore, in the above-described embodiment, the case where the hydraulic cylinder is mounted as the suspension has been described, but this may be a pneumatic cylinder.

Furthermore, the controller 22 in the above-mentioned embodiment can be entirely constituted by electronic circuits such as a counter, a comparator, an amplifier and the like.

[Effect of device]

As described above, according to the present invention, the vehicle speed detecting means is provided with a plurality of vehicle speed sensors forming a redundant system,
When the vehicle speed detecting means is normal, suspension control is performed based on the detected value, and when there is an abnormality such as a failure of the vehicle speed detecting means, the highest value among the detected values by the plurality of vehicle speed sensors is set as the vehicle speed value, and based on this Since suspension control is performed, even if one of the vehicle speed sensors fails and the detected value becomes zero, the detected value related to the failure is reliably excluded and detected normally. Suspension control is continued depending on the vehicle speed value, so if such a failure occurs during turning, stable suspension control can be continued without sudden changes in the body posture, and anxiety for passengers The effect of eliminating the feeling is also obtained, which further enhances the fail-safe function and enables stable posture change suppression control. .

[Brief description of drawings]

FIG. 1 is a diagram showing the outline of the present invention, which corresponds to the scope of claims for utility model registration, FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 3 is a control current supplied to a pressure control valve. FIG. 4 is a graph showing the detection characteristic of the lateral acceleration sensor, FIG. 5 is a block diagram showing the controller, and FIG. 6 is a flowchart showing the processing procedure executed in the controller. Is. In the figure, 10 is a vehicle body side member, 12 is an active suspension device, 14FL to 14RR are suspensions, and 19A and 19B are first and second parts.
A vehicle speed sensor (vehicle speed sensor), 20 is a lateral acceleration sensor, 22 is a controller, 24 is a wheel side member, 26FL to 26RR are front left to rear right hydraulic cylinders, and 28FL to 28RR are front left to rear right pressure control valves.

Claims (1)

[Scope of utility model registration request] 1. A suspension for controlling relative displacement between a vehicle body and a wheel according to a changeable command value, and a posture change detecting means for detecting posture change information according to a posture change of the vehicle body. In an active suspension device configured to change and control the command value based on information, a vehicle speed detecting means having a plurality of vehicle speed sensors, and whether any of the vehicle speed sensors is in a failure state based on the detected values of the vehicle speed detecting means. If the determination result of the failure determination means is not a failure state, the detection value by the vehicle speed detection means is set as a vehicle speed value, and if the determination result is a failure state, Of the values detected by the plurality of vehicle speed sensors, the vehicle speed setting means forcibly setting the highest value as the vehicle speed value, and the vehicle based on the vehicle speed value set by the vehicle speed setting means Is a running state or a stopped state, a driving state determining means, and when the driving state determining means determines that the running state, the command value is changed and controlled according to the posture change information, and An active suspension device comprising: a command value control means for stopping the control of the command value when it is determined that the vehicle is in a stopped state.