JPS628807A - Car suspension provided with level-control function - Google Patents

Abstract

PURPOSE:To improve a degree of responsiveness, by finding a shifting mean value of long and short times with a short cycle, and constituting a car level up-and-down motion so as to be controlled in using a long side in running, a short side in stoppage and also the short side in driving and stopping for a level-control judgment, respectively. CONSTITUTION:A control unit 60 takes in a level-control value of a level-control sensor 61 for the specified time, for example, every 0.2sec, with a short cycle, and calculates a shifting mean value AV20 of relatively long time, for example, 20sec, till just before and another shifting mean value AV2 of relatively short time, for example, 2sec, respectively. And, when a driving system 46 is not outputted, in running, the long time shifting mean value AV20 is set down to a shifting average AV and in stoppage, the short time shifting mean value AV2 to the shifting average AV, respectively, comparing this average AV with the specified output judging valve whereby the driving system 46 is controlled. Then, when the driving system 46 drives and the short time shifting mean value AV2 reaches the specified value, the driving system 46 comes to a stop. With this constitution, a degree of responsiveness is improved without being influenced by a road surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a suspension system for a vehicle that has a vehicle height adjustment function that allows the height of the vehicle body to be adjusted mtr.

[Conventional technology]

BACKGROUND ART Several vehicle suspension systems having a vehicle height adjustment function have been considered. As an example of this type of suspension system, oil or gas is introduced into and taken out of a strut-type suspension mechanism body that is filled with oil and compressed gas.
There is a suspension system that allows the height to be changed. In this vehicle, the vehicle height is constantly monitored by a vehicle height sensor, and the suspension mechanism main body is expanded or contracted based on a signal indicating the vehicle height to maintain the vehicle height at a set vehicle height.

By the way, a running vehicle constantly moves up and down due to unevenness of the road surface. For this reason, it is desirable to determine the vehicle height by taking the average value of the signal from the vehicle height sensor over a certain period of time.

However, if the average value is taken too long, it becomes impossible to quickly adjust the vehicle height, for example when the vehicle is stopped. On the other hand, if the average value is taken too short, the vehicle will react too sensitively to unevenness on the road surface, causing a problem with the stability of the vehicle height.

Therefore, the present inventors proposed Japanese Patent Application No. 177-79 of 1982. This system averages the vehicle height detection signal over a certain period of time and compares it with a predetermined vehicle height setting value to issue control commands to raise, lower, and stop the vehicle height. The energizing control is started only when the monitoring time continues, and if a different control command is generated during the monitoring period, the energizing control is immediately stopped.

[Problems to be solved by the invention] However, in the above prior art, when the vehicle body moves violently up and down, especially when driving on a rough road, the average value easily changes and the same signal continues within the monitoring time. It's hard to do. For this reason, the drive system outputs only when the vehicle height deviates significantly. Also, even if output reaches a certain level,
After that, it was difficult for the same signal to appear consecutively, so the set vehicle height was often not achieved.

Conventionally, after taking a predetermined number of vehicle height sensor values over a predetermined period of time, the average value during this capture time is calculated, and this average value is compared and judged with the vehicle height setting value. There is. Therefore, the vehicle height cannot be determined while the vehicle height sensor values for a predetermined country are being taken in (while averaging is being performed), and the vehicle height may be raised or lowered too much.

In order to solve the above problems, for example, if the averaging time is shortened, the vehicle reacts too sensitively to unevenness of the road surface, making it impossible to obtain an accurate vehicle height value.

[Means for solving problems]

The present invention provides a drive system for expanding and contracting the suspension-like bridge body by supplying oil or compressed gas to and from the suspension-like separate body, such as a suspension-like bridge body provided between a member on the vehicle body side and a member on the wheel side. , a vehicle height sensor that detects the height of the vehicle body, and a control device.

The above control device takes in the vehicle height sensor value at fixed time intervals in a short cycle, and each time the vehicle height sensor value is taken in, it calculates the moving average of the relatively long time up to the previous time, and calculates the moving average of the relatively short time. In addition to calculating the moving average of When the output reaches a predetermined output judgment value, a control command is issued to start the output of the drive system, and the judgment to stop the output is made based on a moving average over a short period of time, regardless of whether the vehicle is moving or stopped. When this moving average reaches a predetermined value, a control command is issued to stop the output of the drive system.

[Effect]

The vehicle suspension system with the above configuration uses the latest vehicle height average value (
Since it is determined whether or not to issue a control command to the drive system based on the moving average, it is possible to prevent the vehicle height from being raised or lowered too much.

Furthermore, the moving average value used as a reference for determining whether or not to output power from the drive system is an average value over a long period of time that has been sufficiently smoothed while the vehicle is running. Furthermore, while the vehicle is stopped, a moving average value for a short period of time is used, but since there is no effect of unevenness on the road surface while the vehicle is stopped, an accurate average value of the vehicle height can be obtained in any case.

Note that when determining the vehicle height value using a moving average, the moving average lags behind the actual vehicle height while the vehicle body is rising or falling due to the output of the drive system. Therefore, by stopping the output based on a value that takes this delay into account, the actual vehicle height can be stopped at a desired position.

Furthermore, the decision to stop the output is made by comparing moving averages over a short period of time, regardless of whether the vehicle is moving or stopped, and when this moving average reaches a predetermined value, the output of the drive system is stopped. I have to. In other words, when stopping the output,
Since the output is stopped based on the moving average of the actual vehicle height over a short period of time with little delay, it is possible to stop the actual vehicle height at a more accurate position.

〔Example〕

The suspension mechanism main body 1 shown in FIG. 1 includes a main actuator 2 and a sub actuator 40.

First, the main actuator 2 will be explained. cylinder 3
A mounting portion 4 is provided at the lower part of the vehicle to be connected to a wheel-side member (not shown). Further, an oil chamber 7 is formed inside the cylinder 3.

A hollow iron 10 is telescopically inserted into the cylinder 3. This hollow rod 10 has an oil chamber 11 inside,
A gas chamber 12 filled with high pressure gas such as nitrogen gas is provided above the oil v11. Further, a damping force generating mechanism 15 is provided at the lower part of the hollow iron 10. This damping force generation mechanism 15 includes a disc valve 16, a variable orifice 17, and the like. The variable orifice 17 can change the cross-sectional area of the flow path according to the rotational position of the rotating body 17a. This rotating body 17a is rotationally driven by a motor 21 via a drive shaft 20.

An end member 23 is attached to the upper part of the hollow iron 10. This end member 23 is provided with a mounting portion 24 that is connected to a member on the vehicle body side. Further, a cover cylinder 25 and a bump rubber 26 are attached to the end member 23.

A gas passage 28 is formed in the end member 23. One end of this gas passage 28 is connected to the gas chamber 12 via an on-off valve 30, and the other end of the gas passage 28 is connected to a gas chamber 43 of a sub actuator 40. The on-off valve 30 is opened and closed by the rotation of the motor 21.

On the other hand, the sub actuator 40 includes a cylinder 41, a partition member 42 provided inside the cylinder 41, a gas chamber 43 and an oil chamber 44 partitioned by the partition member 42.
Consisting of

Further, a drive system 46 is connected to the oil chamber 44 .

The drive system 46 includes, for example, a hydraulic pressure 847, switching valves 48, 49 using electromagnetic valves, an oil tank 50, etc., and controls the partition member 42 by taking oil in and out of the oil chamber 44.
is raised and lowered to change the volume or internal pressure of the gas chambers 12 and 43, thereby changing the amount of expansion and contraction of the main actuator 2.

The switching valves 48, 49 and the motor 21 are controlled by the control device 60.
controlled by This control device 60 receives a signal from a vehicle height sensor 61 that detects the height of the vehicle body.

Further, connected to the control device 60 are, for example, a speed sensor 62, a steering wheel angle sensor 63, a brake sensor 64, an accelerator sensor 65, a parking brake sensor 66, and a switch panel 70.

The controller @60 operates as described below.

FIG. 2 is a flowchart showing an overview of the process.

This control m+ device 60 takes in the vehicle height value from the vehicle height sensor 61 at fixed time intervals (for example, 0.2 seconds) in short cycles. Each time this vehicle height sensor value is taken in, a moving average A V 20 for a relatively long period of time (for example, 20 seconds) up to the time immediately before is calculated. At the same time, a moving average AV2 for a relatively short period of time (for example, 2 seconds) is sequentially calculated. In other words, the long-time moving average AV20 is the latest of the averages of the past 100 vehicle height sensor values, and AV2 is the latest of the averages of the past 10 vehicle height sensor values. Therefore, each of these moving averages is 0.2
Updated every second. That is, each time the latest value is fetched, the oldest value is canceled one by one.

By using the average value representing the vehicle height as a moving average, changes in sensor values affected by the road surface can be considerably smoothed out, and fairly accurate vehicle height values can be obtained every short period of time (for example, 0.2 seconds). can get.

Then, it is determined whether the drive system 46 is currently in the output state. If it is not in the output state, the process moves to an output determination loop 81, which will be described next, and if it is in the output state, the process moves to an output stop determination loop 82, which will be described later.

In the output determination loop 81, it is first determined whether the vehicle is running. If the vehicle is running, the moving average AV20 for a long time is set as the moving average AV.

In addition, the preset driving up output judgment value is
Let p be the output judgment value. Similarly, the down output determination value during running is set as the down output determination value.

Conversely, if the vehicle is stopped, the moving average AV2 for a short period of time is set as the moving average AV. In addition, a preset up output judgment value while the vehicle is stopped is set as an up output judgment value. Similarly, the down output determination value while the vehicle is stopped is set as the down output determination value.

The reason why the UP or DOWN output judgment value is divided between when the vehicle is running and when it is stopped is that when the vehicle is stopped, it is not affected by the unevenness of the road surface, so the range is narrowed and the aim is to achieve accurate and quick response. Also, by making the range relatively wide while driving, we aimed to further reduce the influence of the road surface.

Then, when the moving average AV falls to the up output judgment value, that is, when the vehicle height falls below the set value,
The vehicle is in a ready state for raising the vehicle height. Conversely, when the moving average AV rises to the down output judgment value, that is, when the vehicle height rises above the set value, the vehicle is set in a ready state for lowering the vehicle height.

Otherwise, it remains in a stopped state.

As mentioned above, if the raising or lowering of the vehicle body is decided and the vehicle enters the rady state, and the same signal continues for a predetermined period of time (for example, 0.6 seconds), the identification flag "wait", which will be described later, will be activated.
It is only when tJ is other than 1 that the drive system 46 is actually moved, resulting in an output state of raising or lowering.

When the drive system 46 starts outputting in this way, the switching valves 48 and 49 are operated based on a command to raise or lower the oil, and the partition member 42 is moved up and down by injecting or discharging oil into the oil chamber 44. , As a result, the expansion and contraction of the main actuator 2 is adjusted.

Once the output is started, the flow of processing in the control device 60 immediately moves to the output stop determination loop 82. In this output stop determination loop 82, it is first determined whether the output is in the process of increasing (up) or decreasing (down). When the moving average AV2 reaches a predetermined down stop range, in the case of a descending output, 1 is set in "waitJ" of the output stop judgment loop, and the drive system 46 is stopped.

Further, if AV2 does not reach the down stop range, it continues to be lowered.

On the other hand, in the case of an upward output, when the moving average AV2 reaches a predetermined up stop range, 1 is set in waitJ and the drive system 46 is stopped.

Further, if AV2 has not reached the up stop range, it continues to be raised. If the output continues continuously for more than a certain period of time, it is determined that some kind of failure has occurred and the system is installed to protect the hydraulic circuit.
The drive system 46 may be stopped while setting waitJ to 1.

As described above, while the drive system 46 is in the output state and the vehicle body is rising or falling, the moving average value has a certain delay with respect to the actual vehicle height. That is, while the vehicle is climbing, the moving average value is lower than the actual vehicle height, as shown in FIG. On the other hand, the moving average while falling is higher than the actual vehicle height.

Therefore, when determining the vehicle height value (actual vehicle height) based on the moving average AV2 in the stop determination loop 82, the actual vehicle height can be stopped at the desired position by stopping the output at a value that takes into account this delay. I can do it.

As mentioned above, in the stop judgment loop 82, the moving average AV for a short period of time is determined regardless of whether the vehicle is running or stopped.
2, the judgment is made by comparing it with the up stop range or the down stop range. In other words, when stopping the output, the judgment to stop the output is made based on the moving average AV2 which is less behind the actual vehicle height, so it is possible to stop the actual vehicle height at a more accurate position.

As mentioned earlier, the moving average AV20. AV2 is a value that is slightly behind the actual vehicle height.

In particular, the delay in the moving average AV20 for a long time is considerably larger than the delay in the moving average AV2 for a short time. Because of this time delay, as illustrated in FIG. 3, the moving average value does not match the actual vehicle height until a predetermined time t has passed after the output is stopped.

In other words, the moving average does not reach the actual vehicle height until this time t has elapsed, so even if a control command to raise or lower the vehicle height is issued in the output judgment loop 81, the drive system 4
6 should not be output.

For this reason, an output loop 83 is provided.

That is, after passing through the output stop judgment loop 82 and the vehicle height output is stopped, it immediately enters this output holding loop 83 and is held for a predetermined holding time (15 to 20 seconds while driving, 1 to 2 seconds while stopped). It is determined whether the time period (seconds) has elapsed.

Then, until this waiting time elapses, l"wattJ of the output holding loop 83 remains at 1, and the vehicle height output is maintained at a stopped state.

Then, when the waiting time has elapsed, that is, after the discrepancy between the actual vehicle height and the moving average has almost disappeared, set O to waitJ for the first time.
When the output determination loop 81 determines whether to increase or decrease the output, the drive system 46 starts outputting without waiting.

In addition, if the switch panel 70 is changed while waiting for output (if the vehicle height setting value is changed),
The waiting time is canceled and the output judgment loop 81 is entered immediately.

As shown in FIG. 4, the above processing is performed separately for the front right wheel suspension 91, the front left wheel suspension 92, the rear right wheel suspension 93, and the rear left wheel suspension 94. The vehicle height is adjusted independently by driving the solenoid valve and actuator for each wheel.

In addition, when performing the above-mentioned vehicle height adjustment, when the acceleration in the vehicle width direction calculated from the steering wheel angle and vehicle speed exceeds a certain value, or when a signal from the brake sensor 64 or the accelerator sensor 65 is detected. In such cases, the vehicle height adjustment described above is not performed because the vehicle body may temporarily sway. Furthermore, the acquisition of the vehicle height sensor value is canceled.

In the suspension mechanism main body 1 having the above configuration, when the hollow iron 10 expands and contracts relative to the cylinder 3, the damping force generating mechanism 15
A damping force is generated by the flow of oil. At the same time, the repulsive force of the high pressure gas within the gas chamber 12.43 functions as a spring. Furthermore, by driving the motor 21 based on signals input from various sensors 62 to 65 and simultaneously controlling the variable orifice 17 and the on-off valve 3o, it is possible to stabilize the vehicle body posture and improve riding comfort. .

For example, when the vehicle is traveling straight, the on-off valve 30 is opened to communicate the two gas chambers 12.43, lowering the gas spring constant, and at the same time rotating the variable orifice 17 so that the cross-sectional area of the flow path becomes large. If the body 17a is rotated to reduce the damping force, the riding comfort will be improved. On the other hand, when turning or sudden acceleration,
When stopping suddenly or driving at high speed, use the above sensors 62 to 65.
The motor 21 is driven via the control tII device 60 in response to a signal from the switch panel 70 or a manual operation from the switch panel 70 to open the on-off valve 30 and at the same time open the variable orifice 1.
By reducing the cross-sectional area of the flow passage 7 and increasing the damping force, steering stability can be improved.

〔Effect of the invention〕

According to the present invention, it is possible to determine whether to raise or lower the vehicle height based on the average value of the vehicle height over a relatively long period of time, so the drive system can be adjusted relatively quickly without being greatly affected by the road surface. Control commands can be issued and vehicle height adjustment functions with excellent responsiveness can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a vehicle suspension system according to an embodiment of the present invention together with a control device, FIG. 2 is a flowchart showing the process flow of the control device shown in FIG. 1, and FIG. FIG. 4, which is a diagram showing the relationship between the height and the moving average value, is a schematic diagram showing an example of how the suspension device is used. 1... Suspension mechanism main body, 46... Drive system, 60...
Vice device, 61...Vehicle height sensor.

Claims (1)

[Scope of Claims] A suspension mechanism body provided between a member on the vehicle body side and a member on the wheel side; a drive system that expands and contracts the suspension mechanism body by supplying and extracting oil or compressed gas to and from the suspension mechanism body; The vehicle height sensor detects the height of the vehicle body, and the vehicle height sensor value is acquired at regular intervals in a short cycle, and each time the vehicle height sensor value is acquired, the vehicle height sensor calculates the relatively long time of travel up to the point immediately before the vehicle height sensor value is acquired. In addition to calculating the moving average over a relatively short period of time, while driving, the moving average over a long period of time is compared with a predetermined output judgment value, and when stopped, the moving average over a short period of time is compared with a predetermined output judgment value. In comparison, when the moving average reaches a predetermined output judgment value, a control command is issued to start the output of the drive system, and the judgment to stop the output is made regardless of whether the system is moving or stopped. a control device that compares the moving average over a short period of time and issues a control command to stop the output of the drive system when the moving average reaches a predetermined value. Vehicle suspension system with functions.