JP3019322B2 - Vehicle suspension control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control device for a vehicle, which controls a state of a suspension of the vehicle in accordance with a traveling condition of the vehicle so as to improve ride comfort and operability. Things.

2. Description of the Related Art In recent years, LSIs and microcomputers having complicated arithmetic processing functions have been developed with the progress of semiconductors, and control devices having fine control functions have been realized using these. In addition, the reliability of these control devices has been improved, and a technology has been realized in which normal operation can be guaranteed even in an extremely severe environment such as mounted on a vehicle. Against such a background, it is used particularly for controlling a vehicle that requires fine control. In particular, recently, the development of a suspension control device for improving the riding comfort and the operability of a vehicle has been actively pursued. Conventionally, in a device of this type, disturbances such as a roll of the vehicle and a pitch of the vehicle that occur during the operation of the vehicle are controlled by information from many sensors installed in the vehicle.
The suspension's spring constant, damping force and stroke have been varied to ensure riding comfort and maneuverability.

One embodiment of a conventional suspension control device will be described with reference to FIG. Many sensors are mounted on the vehicle, and information detected by these sensors is input to an electronic control controller 1 which is an arithmetic processing unit, and an actuator built in a shock absorber 2 which is a component of the suspension is switched to reduce a damping force. In this case, the control is performed by making it variable. For example, in order to prevent the tail from sinking during acceleration, an anti-scout function controlled by the input of the throttle position sensor 3 and the vehicle speed sensor 4 and the brake switch 5 to prevent the nose from sinking when braking by braking or engine braking. Dive function controlled by the input of the vehicle speed sensor 4 and anti-dive function controlled by the input of the steering sensor 6 and the vehicle speed sensor 4 to prevent rolling caused by steering operation, and vertical generated by the state of the running road surface The road surface sensor 7 and the vehicle speed sensor 4
And an anti-bounce function controlled by an input of the

In other suspension control systems, the vehicle speed sensor, the throttle position sensor,
There are also examples in which a number of sensors such as an acceleration sensor, a clutch switch, a parking brake switch, and a door switch are used in addition to a brake switch, a steering sensor, and a road surface sensor.

Problems to be Solved by the Invention Generally, when the ride comfort is emphasized, the suspension is set to be soft, and when the stability is emphasized, the suspension is set to be stiff. In the conventional embodiment, when the controllability is more important than the riding comfort, there are many causes of disturbance such as roll, pitch, etc. It captures phenomena and predicts disturbances such as roll and pitch of the vehicle that will surely come next, and changes the state of the suspension.It is intended to capture many phenomena that cause disturbances. There is a possibility that a large number of sensors are required, the control processing is complicated due to the control based on prediction, and there is a possibility that wrong control may not be performed in the worst case because it does not match the actual displacement of the vehicle. Was.

On the other hand, for example, as disclosed in Japanese Patent Application Laid-Open No. 63-68413, a system has been proposed in which the displacement of the vehicle is directly grasped by a small number of sensors to control the state of the suspension.

An object of the present invention is to make it possible to control the state of a suspension with a small number of sensors.

Means for Solving the Problems In order to solve the above problems, the present invention provides a sound or structural vibration type angular velocity sensor, a sensor for detecting displacement of a vehicle in a vertical direction, a vehicle speed sensor, and an output signal of these sensors. An electronic control controller that performs arithmetic processing based on the arithmetic processing, and an actuator provided on a suspension of the vehicle changes a spring constant, a damping force, and a throttle of the suspension based on a result of the arithmetic processing.

Operation With the above configuration, the displacement of the vehicle can be directly and accurately captured by a sound or structural vibration type angular velocity sensor and a sensor that detects the displacement of the vehicle in the vertical direction, such as a roll, a pitch, etc. When the vehicle is stopped or running at high speed, the state of the vehicle is captured by a vehicle speed sensor, and the state of the suspension can be varied in accordance with the output signals of these sensors, so that the riding comfort of the vehicle speed and the operability can be improved.

An embodiment of the vehicle suspension control device according to the present invention will be described below with reference to the drawings.

First, a base or structural vibration type angular velocity sensor for detecting a displacement of a vehicle will be described with reference to FIGS.

The angular velocity sensor has a structure as shown in FIG.
A driving element consisting of two piezoelectric bimorphs, a first and a second sensing element, and a driving element 101 and a first sensing element 103.
A first vibration unit 109, which is orthogonally joined at a joining portion 105,
The monitor element 102 and the second vibration unit 110 in which the second detecting element 104 is orthogonally joined at the joining portion 106 are connected by a connecting plate 107, and the connecting plate 107 is supported at one point by a support rod 108 to provide a sound or sound structure. ing. When a sine wave voltage signal is applied to the drive element 101, the first vibration unit 109 starts vibrating due to the inverse piezoelectric effect, and the second vibration unit 110 also starts vibrating due to sound or vibration. Therefore, the electric charge generated on the element surface by the piezoelectric effect of the monitor element 102 is proportional to the sinusoidal voltage signal applied to the drive element 101. By detecting the charge generated in the monitor element 102 and controlling the sinusoidal voltage signal applied to the drive element 101 so that the charge has a constant amplitude, a stable sound or vibration can be obtained.

The mechanism by which this sensor generates an output proportional to the angular velocity will be described with reference to FIGS. FIG. 6 is a top view of the angular velocity sensor shown in FIG. 5. When rotation of the angular velocity ω is applied to the detecting element 103 vibrating at the speed υ, “Coriolis force” is generated in the detecting element 103. . This “Coriolis force” is perpendicular to the speed υ and has a magnitude of 2 mυω. Since the detection element 103 is oscillating or vibrating, if the detection element 103 is oscillating at a speed υ at a certain point in time, the detection element 104 is oscillating at a speed −υ and the “Coriolis force”
Is 1mυω. Therefore, the sensing elements 103 and 104 are deformed in the direction in which the "Coriolis force" is applied to each other as shown in FIG. Here, υ is the motion caused by the sound or vibration, and if the sound or vibration is υ = a · sin ωot a: the amplitude of the sound or vibration ωo: the period of the sound or vibration, the “Coriolis force” is Fc = a · sin ωot, which is proportional to the angular velocity ω and the sound or amplitude a, and serves as a force for deforming the detection elements 103 and 104 in the plane direction. Therefore, the surface charge Q of the detection elements 103 and 104 becomes Q∝a · ω · sin ωot, and if the sound or amplitude a is controlled to be constant, Q∝ω · sin ωot and the surface charge Q generated in the detection elements 103 and 104 Is obtained as an output proportional to the angular velocity ω. If this signal is synchronously detected by ωot, a DC signal proportional to the angular velocity ω can be obtained.
Even if a translational motion other than the angular velocity is given to this sensor, electric charges of the same polarity are generated on the two element surfaces of the detection element 103 and the detection element 104. Therefore, when converted into a DC signal, they cancel each other out and the output is output. There is no such thing.

FIG. 1 shows an embodiment of a vehicle suspension control apparatus according to the present invention. The sound or structural vibration type angular velocity sensor 11, the ultrasonic road surface sensor 12, and the vehicle speed sensor described above with reference to FIG.
A suspension control device comprising an electronic controller 14 comprising 13 sensor groups and performing arithmetic processing based on output signals of these sensors, and an actuator 15 for varying the damping force of a shock absorber which is a component of the suspension. .

FIG. 2 is a diagram in which the above-described sensor, control unit, and actuator are mounted on a vehicle. The angular velocity sensor 11 has an angle of 45 degrees with respect to the X axis, which is the traveling direction of the vehicle, and the Y axis, which is the vehicle width direction. Are mounted so that the axis having the relationship of becomes the detection axis. With this configuration, one angular velocity sensor can detect the angular velocity in the roll direction generated on the X axis and the angular velocity in the pitch direction generated on the Y axis. The ultrasonic road surface sensor 12 is attached to a lower portion of a chassis of the vehicle so as to detect a displacement of the vehicle in a vehicle height direction, and detects one side of the vehicle in a vertical direction. Further, the vehicle speed sensor 13 outputs a digital signal according to the traveling of the vehicle. A sensor group attached to these vehicles detects the posture of the vehicle, and is processed by the electronic control controller 14 so as to minimize displacement of the vehicle due to disturbance, so as to improve ride comfort and maneuverability, It controls an actuator 15 that varies the damping force of a shock absorber, which is a component of the suspension. The specific operation will be described with reference to FIGS. 3 and 4. FIGS. 3 and 4 are based on signals from various sensors,
FIG. 4 shows control during boarding and running and control for disturbance phenomena to be controlled. First, the running state of a normal vehicle is roughly divided into three. If the vehicle is stopped or running at low speed (approximately 0 to 5 km / h), the change in the load of the entire vehicle due to a person entering the vehicle at the time of stopping, getting off and taking in / out luggage, and disturbance immediately after departure or immediately before stopping may be considered. The suspension state is set firmly (stop function). If the vehicle is running at medium speed (about 5-80km / h),
The suspension state is set to be soft unless there is any disturbance in order to emphasize riding comfort (medium speed running tense function). If the vehicle is traveling at high speed (about 80-km /
h), the state of the suspension is set firmly in order to attach importance to maneuverability (high-speed driving control function). Here, when the vehicle is stopped, traveling at low speed, or traveling at high speed, the suspension is unconditionally rigidly set so that the displacement of the vehicle with respect to disturbance does not increase.

Next, when the vehicle is running at medium speed (about 5 to 80 km / h), the suspension is set to be soft to improve the ride comfort, but as soon as disturbance enters, the suspension is set to be firm and the vehicle Controlled to minimize displacement. For example, as shown in FIG.
Since the vehicle is displaced in the roll direction, an angular velocity is generated in the X-axis direction, and a signal detected by the angular velocity sensor 11 is sent to the electronic control controller 14. The electronic control controller 14 tightens the suspension to the actuator 15 as an anti-roll function. Send a command to Also, as shown in FIG. 4 (a), when the vehicle is rapidly accelerated, an angular velocity is generated in the Y-axis direction because the vehicle is displaced in the pitch direction, and a signal detected by the angular velocity sensor 11 is sent to the electronic control controller 14. Then, as an anti-scout function, the electronic control controller 14 sends a command to the actuator 15 to harden the suspension.
Similarly, as shown in FIG. 4 (c), an angular velocity is generated in the pitch direction also during control such as braking, and a command is sent to strengthen the suspension as an anti-dive function.
Further, as shown in FIG. 4 (d), when there is a protrusion or a dent on the traveling road surface, or when the vehicle is vertically swung due to the road surface condition, the vehicle is displaced in the Z-axis direction which is the vehicle height direction. Is generated, a signal detected by the road surface sensor 12 is sent to the electronic control controller 14, and the electronic control controller 14 sends a command to the actuator 15 to make the suspension firmer as an anti-bounce function. After these disturbances have subsided, the suspension returns to soft by the normal medium-speed running tense function.

In the above-described embodiment, the road surface sensor that detects the state of the road surface using ultrasonic waves has been described as a sensor that detects the vertical displacement of the vehicle. Is also good. In the embodiment, the shock absorber of the suspension is controlled by the actuator, but the spring constant and the stroke of the suspension can be controlled by the actuator.

Effect of the Invention As described above, the present invention provides a sound or structural vibration type angular velocity sensor, and a sensor for detecting a vertical displacement of both,
The vehicle speed sensor can directly detect the displacement due to the disturbance of the vehicle, control the spring constant, damping force and stroke of the suspension, and provide a suspension control device that takes into consideration the riding comfort and maneuverability of both. .

In addition, a road surface sensor or an acceleration sensor that uses ultrasonic waves as a sensor to detect the vertical displacement of the vehicle is arranged, and the angular velocity sensor detects axes that are at 45 degrees to each other in the vehicle traveling direction and the vehicle width direction. By disposing the sensor as the axis, the displacement of the roll and the bitch can be detected, and the displacement due to the disturbance of the vehicle can be accurately captured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a suspension control device according to the present invention, FIG. 2 is a schematic diagram showing a mounting state of a sensor on a vehicle, FIG. 3 and FIG. FIG. 5 is a perspective view of the sound or structural vibration type angular velocity sensor in FIG. 2, FIGS. 6 and 7 are explanatory diagrams of the operation, and FIG. 8 is a vehicle mounting state showing one embodiment of a conventional suspension control device. FIG. 11 ... Angular velocity sensor, 12 ... Road surface sensor, 13 ... Vehicle speed sensor, 14 ... Electronic controller, 15 ... Actuator, 101 ... Drive element, 102 ... Monitor element, 103 ...
... 1st detection element, 104 ... 2nd detection element, 105,106 ...
... Joints, 107... Connecting plate, 109... First vibration unit, 110.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihiko Ichise 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Jiro Terada 1006 Odaka Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd (72) Inventor Kazumitsu Ueda 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (56) References JP-A-62-34885 (JP, A) JP-A 62-55210 (JP, A) JP-A-62-122812 (JP, A) JP-A-63-305015 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60G 17/015

Claims (4)

(57) [Claims] An angular velocity sensor having an axis parallel to a road surface on which the vehicle runs and having an angle of 45 degrees with respect to an X axis in a traveling direction of the vehicle and a Y axis in a width direction of the vehicle; A sensor for detecting vertical displacement of the vehicle, a vehicle speed sensor for detecting the vehicle speed, an arithmetic processing unit for performing arithmetic processing based on these sensor output signals, and a control unit which is controlled based on the arithmetic processing and is provided in a vehicle suspension. A suspension controller for a vehicle, comprising: an actuator, wherein the actuator controls a posture of the vehicle by changing a spring constant, a damping force, a stroke, and the like of the suspension. 2. An angular velocity sensor comprising: a first vibration unit in which a driving piezoelectric bimorph element and a first detecting bimorph element are orthogonally joined to each other; and a monitoring piezoelectric bimorph element and a second detecting bimorph element. And a second vibration unit which is orthogonally joined to each other and
An angular velocity sensor having a tuning fork structure in which the free ends of the driving piezoelectric bimorph element and the monitoring piezoelectric bimorph element are connected by a connecting plate so that the second vibration unit is parallel to each other along the detection axis. The vehicle suspension control device according to claim 1, wherein: 3. The vehicle suspension control device according to claim 1, wherein the sensor for detecting the vertical displacement of the vehicle comprises a road surface sensor for detecting a road surface state using ultrasonic waves. . 4. The vehicle suspension control device according to claim 1, wherein the sensor for detecting the vertical displacement of the vehicle comprises an acceleration sensor for detecting the acceleration of the vehicle.