JPH05213031A - Damping force control device for suspension - Google Patents

Abstract

PURPOSE:To ensure the continuation of such abnormal control state as causing a crew's uneasiness to be properly prevented for coping with his/her riding comfort, and enable quick response to be made through control with less interrupting processes using a simple logic. CONSTITUTION:In the case of basic processing, a judgement value A is calculated from a springing speed X' and a relative speed Y', and converted to a damping force F. This force F is further converted to control voltage V, thereby adjusting the opening of a variable throttle valve 7 (steps 110 to 114). Regarding error processing, the occurrence of an error is identified, if state where the peak-to-peak value X'P of the springing speed X' is equal to or above the predetermined level value X'L, continues throughout the 'n'-times of processing. In this case, a signal for stopping or initializing damping force control is outputted to a basic processing block 114 (steps 120 to 123). According to this system, proper reaction can be taken against such other errors than a sensor error as difficult to be directly detected, including an error where a stepping motor cannot be controlled at a proper step angle for some reason.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling the damping force of a suspension having a variable damping force provided in a vehicle.

[0002]

2. Description of the Related Art Conventionally, various types of devices have been known which use a variable damping force type suspension to suppress vibration of a vehicle body while the vehicle is traveling to realize a comfortable traveling state for a driver. In these devices, the behavior of the vehicle body is detected by an acceleration sensor or a vehicle height sensor attached to the vehicle body, and the damping force control based on the displacement damping theory is executed based on this behavior.

By the way, in such a damping force control device,
For example, various abnormalities such as failure of acceleration sensor and vehicle height sensor, disconnection of various signal lines, step motor for damping force adjustment that prevents it from being controlled to the correct operating position due to step-out, etc. The control cannot be performed, and the damping force control may be the control in the opposite direction in some cases. In such a case, the damping force control rather gives an occupant an uncomfortable feeling.

Then, as a control at the time of abnormality such as disconnection of a signal line, for example, there is a proposal of JP-A-60-131309. The proposed device determines the presence or absence of an abnormality based on whether or not the damping force setting state and the actual control state match or not,
In the case of an abnormality, a configuration is adopted in which the normal state is forcibly controlled.

Further, a technique for detecting and notifying an abnormality of a vehicle height sensor (for example, Japanese Utility Model Laid-Open No. 63-112109) or a technique for detecting and notifying an abnormality of an acceleration sensor (for example, Japanese Patent Laid-Open No. 1-03507). Also, a technique has been proposed in which the pressure of a fluid spring of a suspension unit is detected and roll control is prohibited when the pressure is equal to or higher than a set value (Actual No. 1-62110).

[0006]

SUMMARY OF THE INVENTION These various techniques are
The purpose is not to continue the damping force control that makes the occupant feel uncomfortable. However, all of them are premised on a configuration for judging each individual cause of abnormality, and it is not a complete solution to carry out each independently.

On the other hand, it is conceivable to combine these techniques in order to cover all the causes of abnormality, but in this case, the decision logic becomes complicated and a large amount of interrupt processing is required, so that quick control cannot be executed. , Control errors are also likely to occur. A technique for controlling these in accordance with relative vibration between the sprung and unsprung parts
No. 0712) can be considered, but even if such relative vibration is large, the occupant does not feel discomfort if the sprung mass is stable, and conversely, even if the relative vibration is small, the sprung mass The actual situation is that the occupant feels uncomfortable when the vibration is unstable. Therefore, the application of this technology cannot guarantee a truly comfortable riding comfort for the passenger.

Therefore, in the present invention, regardless of the cause, it is possible to prevent the abnormal control from continuing to cause an occupant to feel uncomfortable in accordance with the actual ride comfort of the occupant. It was decided to provide a suspension damping force control device capable of reliably preventing the increase of such control.

[0009]

A damping force control device for a suspension according to the present invention, which has been completed to achieve the above object, comprises a suspension capable of variably controlling the damping force,
Damping force of suspension having vehicle body behavior detecting means for detecting vehicle body behavior, and damping force control means for variably controlling damping force of the suspension by calculating a target damping force based on the detected vehicle body behavior In the control device,
Sprung vibration detection means for detecting the magnitude of sprung vibration,
Based on the magnitude condition judging means for judging whether the detected sprung vibration is larger than a predetermined value and the judgment result of the magnitude condition judging means, the sprung vibration larger than the predetermined value continues for a predetermined time or longer. Based on the result of the continuation condition determination means and the determination result of the continuation condition determination means, if the sprung mass vibration larger than a predetermined value continues for a predetermined time or more, the damping force control means And an instructing unit for instructing to stop or initialize the control.

According to the suspension damping force control device of the present invention, the control by the damping force control means is stopped or initialized when the sprung mass vibration larger than the predetermined value continues for a predetermined time or longer. For example, in an apparatus configured to use a step motor as the damping force variable actuator,
Initialization processing is performed to stop changing the step angle control instruction to the step motor and fix the step angle at that time, or to forcefully return to the position of the step angle "0". As a result, the vibration state that makes the current occupant feel uncomfortable is reduced, and in the case of initialization, the current unpleasant control can be eliminated.

In the present invention, the magnitude condition determining means may determine whether or not the sprung mass is larger than a predetermined value based on the magnitude of the sprung mass about the diagonal line of the vehicle. In this case, it is possible to realize control in which the sprung mass is regarded as one surface, and it is possible to prevent problems such as an uncomfortable roll being increased due to some abnormal control.

In each of the above-described inventions, it is possible to take measures against the abnormality that suits the occupant's sensation, and since it is possible to deal with the abnormality regardless of the cause, the control is not complicated.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a configuration diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a sectional view of the cylinder device shown in FIG. 1, FIG. 3 is a sectional view of the accumulator shown in FIG. 1, and FIG. 4 is a variable diaphragm shown in FIG. FIG. 5 is a cross-sectional view of the valve 7, FIG. 5 is a block diagram illustrating control processing as the first embodiment, and FIG. 6 is a block diagram illustrating control processing as the second embodiment.

FIG. 1 is a block diagram of a strut type suspension system showing an embodiment of the present invention. In FIG. 1, between the vehicle body 1 and the unsprung member 3 connected to the wheels,
A coil spring 6 that acts to soften the impact from the road surface and not transmit it directly to the vehicle body, and a cylinder device as a shock absorber that damps vibrations of the coil spring 6 are arranged.

A cross-sectional view of this cylinder device is shown in FIG.
In FIG. 2, the coil spring 6 is arranged between the upper support 33 provided in the lower portion of the vehicle body 1 and the spring receiving member 38 connected to the cylinder 5. The piston rod 31 is supported by the upper support 33 and the cushion damper 32. A piston 31a is connected to one end of the piston rod 31, and the piston 31a is slidably arranged inside the cylinder 5. Therefore, the cylinder 5 has the piston 31a.
It is divided into an upper chamber 35 and a lower chamber 34 by. The upper chamber 35 and the lower chamber 34 communicate with each other through a communication port 37a provided on the piston 31a. As a result, when the piston 31a slides inside the cylinder 5, the working oil flows through the communication port 37a.

A pipe line 36 is formed inside the piston rod 31, and this pipe line 36 communicates with a communication port 37.
It communicates with the lower chamber 34 via c, and communicates with the upper chamber 35 via a communication port 37b. This conduit 36 is an oil conduit 39.
Is connected to an accumulator 8 via a variable throttle valve 7 provided in the. A sectional view of the accumulator 8 is shown in FIG. In FIG. 3, a left cap 41 is screwed to the left end of the cylinder 40, and a right cap 42 is screwed to the right end thereof. A free piston 44 is slidably arranged inside the cylinder 40. For this reason,
The interior of the cylinder 40 is partitioned by a free piston 44 into a hydraulic chamber 45a and a gas chamber 45b. The stopper 43 is fixed to the left end portion of the cylinder 40 by a left cap 41, and the hydraulic chamber 45a of the free piston 44 is fixed.
The sliding in the direction is restricted. The hydraulic oil from the cylinder 5 is introduced into the hydraulic chamber 45a via the pipe 36 and the oil passage 39, and gas is enclosed in the gas chamber 45b.

The accumulator 8 stores the working oil discharged from the upper and lower chambers 34 and 35 of the cylinder 5 and supplies the working oil to the upper and lower chambers 34 and 35 of the cylinder 5. That is, when the piston 31 a slides inside the cylinder 5, the volume in the cylinder 5 changes by the volume of the piston rod 31 that moves in and out of the cylinder 5. When this capacity decreases, the surplus hydraulic oil is discharged to the accumulator 8. On the other hand, when the capacity increases, a shortage of hydraulic oil is supplied from the accumulator 8 to the upper and lower chambers 34, 35.

The accumulator 8 has a hydraulic chamber 45a.
When hydraulic oil flows into or out of the hydraulic chamber 45a, it also functions as a gas spring due to the compression elasticity of the gas sealed in the gas chamber 45b. Therefore, it is possible to mitigate the hydraulic shock that accompanies the opening and closing of the variable throttle valve 7, and also to mitigate the shock when the wheel bumps on the vehicle.

A variable throttle valve 7 is provided in an oil passage 39 connecting the accumulator 8 and the upper and lower chambers 34, 35 of the cylinder 5. The damping force can be varied by adjusting the opening area of the oil passage 39 with the variable throttle valve 7. A sectional view of the variable throttle valve 7 is shown in FIG.

In FIG. 4, a bush 51 is press-fitted into the right end portion of the housing 50, and the outside of the bush 51 is screwed with a bolt 53 via a stopper 52. Inside the housing 50, the bush 5
A hollow shaft 54 pivotally supported by 1 and a rotor 55 integrated with the shaft 54 are rotatably arranged. The shaft 54 and the rotor 55 are rotated by the rotating magnetic field generated by the coil 60. Further, in order to take out the wire 61 for supplying current to the coil 60 to the outside, the connector block 63 is attached to the housing 50 with screws 6.
It is attached by 4. The connector block 63 is provided with a terminal 62 that is connected to the wire 61, so that an electric current can be supplied from the outside. In addition,
Sealing material is injected into the inner side 65a and the outer side 65b of the connector block 63.

A plate 56 is press-fitted into the left end portion of the housing and fixed by screws. A bush 57 is press-fitted into the plate 56, and one end of the shaft 54 is rotatably supported by the bush 57. Further, the plate 56 is formed with a port 59a communicating with the upper and lower chambers 34, 35 of the cylinder 5 and a port 59b communicating with the accumulator 8. The port 59a communicates with the triangular hole 58 and the circular hole 67 formed in a part of the shaft 54 through the oil ports 66a and 66b. On the other hand, the port 59b is connected to the shaft 5
It communicates with the triangular hole 58 and the circular hole 67 formed in the shaft 54 through the hollow portion of No. 4. That is, the ports 59a and 59b communicate with each other through the triangular hole 58 and the circular hole 67.

Here, the outer diameter of the shaft 54 at the portion where the triangular hole 58 is provided on the side surface is set so that the outer periphery of the shaft 54 contacts the outer member 68 and can rotate in a liquid-tight state. There is. On the other hand, the outer diameter of the shaft 54 in the portion where the circular hole 67 is provided on the side surface is set smaller than the outer diameter of the portion where the triangular hole 58 is provided in the side surface. Further, the oil port 66 communicating with the port 59a
a is a shaft 5 having a triangular hole 58 on its side surface.
4 and the oil port 66b is configured to communicate with the surface portion of the shaft 54 having a circular hole 67 on the side surface.

Therefore, when the rotating magnetic field is generated by the coil 60 and the rotor 55 is rotated, the shaft 54 is also rotated together with the rotor 55. By rotating the shaft 54 to change the position of the triangular hole 58, the opening area of the hydraulic oil flow path can be adjusted. That is, for example, when the hydraulic oil flows from the port 59a to the port 59b,
First, the hydraulic oil flows to the oil ports 66a and 66b. The hydraulic oil flowing into the oil port 66b has a circular hole 67 on the side surface.
Flows to the surface portion of the shaft 54 where is provided. Further, the hydraulic oil is supplied to the hollow shaft 54 through the circular hole 67.
It flows inward and reaches the port 59b. On the other hand, oil port 66
For the oil that has flowed to the a, the triangular hole 58 has an oil port 66.
If even a part of it is in contact with a, it will flow from that part into the hollow shaft 54 and reach the port 59b. However, if the triangular hole 58 is not in contact with the oil port 66a, the hydraulic oil does not flow through the triangular hole 58. In this way, the opening degree of the variable throttle valve 7 is determined according to the area of the triangular hole 58 opening to the oil port 66a. However, since the circular hole 67 is normally open, the triangular hole 58
Even if the valve is fully closed, the hydraulic oil flows to the port 59b little by little.

The vehicle height sensor 4, as shown in FIG.
Is disposed between the unsprung member 3 and the unsprung member 3, and detects the relative displacement amount of the vehicle body 1 and the unsprung member 3 to detect the electronic control device (EC
U) Output to 9. The acceleration sensor 2 is arranged at a lower portion of the vehicle body 1, detects the vertical acceleration acting on the vehicle, and outputs it to the ECU 9.

The ECU 9 is a well-known one composed of a CPU, a ROM, a RAM, etc., and controls the opening of the variable throttle valve 7 based on detection signals from the acceleration sensor 2, the vehicle height sensor 4 and other sensor groups. adjust. Next, the operation of the ECU 9 in the configuration described above will be described.

FIG. 5 is a block diagram for explaining the operation of the ECU 9. In this embodiment, as shown in block 110, detection signals (sprung acceleration) X ″ from four acceleration sensors 2 attached to the vehicle body 1 near each wheel are digitally integrated to determine the sprung member. Travel speed (Spring speed)
Find X '. The sprung speed X'indicates the vibration state of the vehicle body 1. On the other hand, as shown in block 111, a value Y'which is obtained by digitally differentiating the relative displacement Y is obtained based on the detection signals (relative displacement) Y from the vehicle height sensors 4 provided for the four wheels. This value Y'is a relative speed between the sprung member and the unsprung member, and is hereinafter referred to as relative speed Y '.

The sprung speed X'and the relative speed Y'calculated in this way are sent to the block 112. Block 11
In 2, the value obtained by dividing the sprung speed X ′ by the relative speed Y ′ is calculated as the determination value A. The judgment value A calculated in this way
Is sent to the block 113 and converted into a damping force F.
A conversion map as shown is used for this conversion. This damping force F becomes a target value of the damping force in the control thereafter.

When the target damping force F is calculated in this way, the data is sent to the block 114 and the process of converting the damping force F into the control voltage V is executed. Then, the control voltage V is applied to the coil of the variable throttle valve 7, a current is supplied, the rotor 55 rotates, and the throttle is adjusted.

Blocks 110 for the above basic processing
The damping force variable control according to the behavior of the vehicle is performed by 114, and so-called skyhook control is performed based on the displacement damping theory. In the present embodiment, not only the blocks 110 to 114 for this basic processing, but also blocks 120 to 123 for abnormal processing for detecting and coping with abnormal vehicle behavior are added. Is characterized by.

In the first block 120 for the abnormality processing, the difference (peak-to-peak) between the "+ side" peak and the "-side" peak of the sprung mass speed X'calculated in the basic processing block 110 is calculated. Value) X'P is calculated. And
This peak-to-peak value X′P is sent to the next block 121. Here, the peak-to-peak value X'P is calculated for each wheel, and blocks 121 and below are processed for each wheel.

At block 121, a comparison / determination is made as to whether or not the peak-to-peak value X'P is equal to or higher than a predetermined level value X'L. If “YES” is determined, the process proceeds to the next block 122 for abnormal processing. On the other hand, when it is determined to be "NO", the process returns to the start and waits for calculation.

In block 122, it is determined whether or not the state determined to be "YES" in block 121 continues continuously for a predetermined number of times n of calculations. When the number of continuations reaches n, the process proceeds to the next block 123 for the first time. When the number of continuations is less than n, the process returns to the start and waits for the next calculation.

The block 123 is a block which is executed only when it is determined that the peak-to-peak value X'P is equal to or greater than the level value X'L and continues n times continuously. A signal for stopping or initializing the control is output to the basic processing block 114. This output has priority over the output from the basic processing block 113. Therefore, when the process of block 123 is executed, the throttle state of the variable throttle valve 7 is fixed to the operating position at that time, or is forcibly returned to the position of the step angle "0". Here, the return to the step angle "0" is
It is easily realized by rotating the rotor until it hits a stopper provided at a predetermined position. Although this stopper is arranged in advance in a state where the damping force is soft, it may be configured such that a normal intermediate between soft and hard is the initial state. Although the processing of blocks 120 to 123 is performed for each wheel, the suspension or initialization of control when it is determined to be abnormal is executed for all wheels.

As described above, according to this embodiment, by adding the blocks 120 to 123 for abnormality processing,
When an abnormality occurs during execution of so-called skyhook control, the damping force variable control is stopped at that point or the damping force variable control is returned to the initial state.

At this time, since the structure is determined to be abnormal when the sprung vibration state is larger than a predetermined value and does not fall within a predetermined time, an appropriate abnormality processing is performed under the same condition that an occupant feels uncomfortable. Can be configured to run. Further, focusing on the fact that the sprung mass gives the occupant an uncomfortable feeling, it does not matter what causes such uncomfortable control. Therefore, it is necessary to take appropriate measures not only for various sensor abnormalities, disconnection of switches, etc., but also for abnormalities that are difficult to detect directly other than sensor abnormalities such as the step motor not being controlled to the correct step angle for some reason. You can

Further, since the final state of the occupant's discomfort can be reliably determined only by the condition related to the sprung vibration, a simple control logic is sufficient and can be realized by a small interruption process. Therefore, quick response is possible. Further, since it is simple, there is no error in the determination.

Next, a second embodiment will be described. The second embodiment, as shown in FIG. 6, is a block 120 of the first embodiment.
Since ~ 122 has been changed, only different points will be described. In the abnormal processing interrupt, the first block 130 is the same as the block 120 of the first embodiment.
Sprung speed X '(FL), X' (FR) in each wheel,
Peak-to-peak values of X '(RL), X' (RR) X'P (FL), X'P (FR), X'P (RL),
Calculate X'P (RR).

In the following block 131, the block 130
Peak-to-peak value X'P of each wheel calculated by
(FL), X'P (FR), X'P (RL), X'P
Based on (RR), the components (diagonal linear velocities) X'SA and X'SB on the diagonal line of the vehicle are calculated. That is, the peak-to-peak value X'P (FL) of the left front wheel minus the peak-to-peak value X'P (RR) of the right rear wheel, and the peak-to-peak value of the right front wheel. A value X′SB obtained by subtracting the peak-to-peak value X′P (RL) of the left rear wheel from the peak value X′P (FR) is calculated.

In block 132, if one of the diagonal linear velocities X'SA and X'SB calculated in block 131 is greater than or equal to a predetermined value X'SL, the next abnormality processing block 13
Go to 3. On the other hand, when it is less than the predetermined value, the process returns to the start and enters the input waiting state. In block 133, the state determined to be “YES” in block 132 is the predetermined value n.
Determine if it is continuous. If it is continuous, the routine proceeds to block 123, where the damping force variable control is stopped or the control position of the variable throttle valve is returned to the initial state, as in the first embodiment. On the other hand, if it has not been repeated n times, the process returns to the start and waits for an input signal.

With this configuration, according to the device of the second embodiment, when the vehicle body 1 is viewed as a surface, a large vibration state, that is, a state in which large rolls, pitches, and bounces occur is continued for a predetermined time or longer. If so, it is determined that normal control is not performed due to some abnormality, the damping force variable control is stopped, or the control is returned from the initial state. As a result, it is possible to prevent at least uncomfortable rolls, pitches, bounces, and the like from being increased, and it is possible to correct to a comfortable control state when initialization is performed.

In each of these embodiments, it is confirmed in block 122 or block 133 that such a state is not sporadic, not that it is immediately determined to be abnormal simply by the magnitude of the vibration level. Therefore, it is also excellent in that it is not judged as abnormal by a large vibration that happens to occur due to the condition of the road surface.

The main usage of each embodiment is as follows.
The embodiment is effective for the detection when the four wheels are independently controlled, and the second embodiment is suitable as the detection when the vehicle is controlled by performing the mode conversion that divides the vehicle into motions such as roll, pitch and bounce. Although the embodiments of the present invention have been described above, the present invention is not limited to the configuration in which the determination is made based on the sprung mass velocity as in the embodiment, and the abnormality determination is performed by using sprung mass acceleration or sprung jerk (differential value of acceleration). It suffices to detect and control a parameter capable of determining the magnitude of the upper vibration, and various modes can be implemented without departing from the gist of the parameter.

[0043]

As described above in detail, according to the suspension damping force control apparatus of the present invention, the structure which takes into account the sprung vibration and judges and copes with the abnormality is adopted. Accordingly, it is possible to accurately prevent the abnormal control that causes the passenger from feeling uncomfortable.
At this time, it is not necessary to make a determination for each cause of abnormality as in the conventional technique, and a simple control logic is sufficient, and it can be realized by a small amount of interrupt processing. Therefore, quick response is possible. Further, since it is simple, there is no error in the determination.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a basic device configuration of an embodiment.

FIG. 2 is a sectional view of the cylinder device shown in the embodiment.

FIG. 3 is a cross-sectional view of the accumulator in the example.

FIG. 4 is a sectional view of a variable throttle valve according to an embodiment.

FIG. 5 is a block diagram illustrating a control process as a first embodiment.

FIG. 6 is a block diagram illustrating a control process as a second embodiment.

[Explanation of symbols]

1 ... vehicle body, 2 ... acceleration sensor, 3 ... unsprung member, 4 ... vehicle height sensor, 5 ... cylinder, 6 ...
-Coil spring, 7 ... Variable throttle valve, 8 ... Accumulator, 9 ... ECU, 55 ... Rotor, 60
···coil.

Claims (2)

[Claims] 1. A suspension capable of variably controlling a damping force, a vehicle body behavior detecting means for detecting a behavior of a vehicle body, a target damping force is calculated based on the detected vehicle body behavior, and a damping force of the suspension is calculated. In a suspension damping force control device having a damping force control means for variably controlling, a sprung vibration detection means for detecting the magnitude of sprung vibration,
Based on the magnitude condition judging means for judging whether the detected sprung vibration is larger than a predetermined value and the judgment result of the magnitude condition judging means, the sprung vibration larger than the predetermined value continues for a predetermined time or longer. The continuation condition determining means for determining whether or not the damping force control means determines whether or not the sprung mass vibration larger than a predetermined value continues for a predetermined time or more based on the determination result of the continuation condition determining means. A damping force control device for a suspension, comprising: an instruction means for instructing suspension or initialization of control by the. 2. The magnitude condition determining means determines whether or not the sprung mass is larger than a predetermined value based on the magnitude of the sprung mass about a diagonal line of the vehicle. Suspension damping force control device.