JPH06320929A - Suspension controller - Google Patents

Abstract

PURPOSE:To provide a suspension controller adapted to the state of a road surface by controlling the width of a dead zone of a relative speed according to one among a spring speed, a relative speed measuring means between the upper and lower sides of a spring, the state of the road surface and a running state, and outputting a signal on the ratio of the above speeds. CONSTITUTION:A suspension controller has acceleration sensors 10A to 10C to detect the vertical accelaration of a spring member, a spring speed measuring means 1 and displacement sensors 20A to 20D to detect the vertical displacement of the spring member, and is composed of a relative speed measuring means 2 between the upper and lower sides of the spring; a controller 3 which, after mode-converting the spring speed and the relative speed, reversely converts them for judging the state of the road surface where a car is running, and controls the width of a dead zone of the spring speed and the relative speed, which are reversely converted according to the judged state of the road surface, to obtain a speed ratio for outputting a control signal; and an actuator 4 to control the opening area of a variable choking mechanism arrangedly provided between the cylinder piston device of an absorber of a suspension mechanism and an accumulator on the above control signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the dead band width of the relative speed or the sprung speed in accordance with at least one of the road surface condition, the vehicle speed, and other running conditions to control the sprung speed and the relative speed. The present invention relates to a suspension control device that controls a damping force by a control signal based on a speed ratio that is a ratio of

[0002]

2. Description of the Related Art A conventional suspension control device (Japanese Patent Laid-Open No. 3-276806) uses a speed dZ1 of the sprung member of each wheel.
Since / dt to dZ4 / dt is divided by the relative displacement speed dY1 / dt to dY4 / dt of the unsprung member with respect to the sprung member, the displacement speed dY1 / dt to dY4 / dt may be "0". In order to obtain the above, the CPU calculates the displacement speed dY1 according to the table shown in FIG.
/ Dt to dY4 / dt were corrected. That is, in order to prevent hunting of the speed ratio, the displacement speed dY
When the absolute value of 1 / dt to dY4 / dt is smaller than the predetermined value, the dead band width is uniformly set to the constant values ε and −ε.

[0003]

Since the above-mentioned conventional suspension control device controls with a constant dead band width, if the dead band width is set to, for example, a good road, unnecessary control is performed on a bad road. When the dead zone width is set to a bad road, the necessary control is not performed on a good road, and there is a problem with the vehicle speed.

Therefore, the present inventors have found that the road surface condition, the vehicle speed,
Focusing on the technical idea of the present invention of optimally controlling the dead band width of the relative speed or the sprung speed according to other running conditions, as a result of further research and development, the road surface condition, vehicle speed, and other running conditions The present invention has been achieved which achieves the object of solving the control problem associated with changes in

[0005]

A suspension control device of the present invention (the first invention according to claim 1) is provided between a wheel support member and a vehicle body, and a damping force is provided in accordance with a drive amount of a drive mechanism. In the suspension control device for controlling the sprung speed, a sprung speed measuring means for measuring a sprung speed, a relative speed measuring means for measuring a relative speed between the sprung portion and the unsprung portion, at least a road surface state, a vehicle speed or other running state. A controller that controls the dead band width of the relative speed output by the relative speed measuring means according to any one of them, and outputs a control signal based on a speed ratio that is a ratio between the sprung speed and the controlled relative speed of the dead band width. It consists of and.

The suspension control device of the present invention (the second invention according to claim 2) is provided between the wheel support member and the vehicle body, and controls the damping force according to the drive amount by the drive mechanism. In accordance with at least one of the sprung speed measuring means for measuring the sprung speed, the relative speed measuring means for measuring the relative speed between the sprung portion and the unsprung portion, and the road surface condition, the vehicle speed, or another running condition. And a controller that controls the dead band width of the sprung speed output by the sprung speed measuring means and outputs a control signal based on the speed ratio that is the ratio of the sprung speed and the relative speed in which the dead band width is controlled. Is. The relative speed is set such that a dead zone having a constant positive or negative value is provided within the dead zone, or a value of zero cannot be taken.

[0007]

The suspension controller of the first aspect of the present invention having the above structure controls the dead band width of the relative speed output by the relative speed measuring means in accordance with at least one of the road surface condition vehicle speed and other running conditions, The controller outputs a control signal based on the speed ratio, which is the ratio of the sprung speed to the relative speed in which the dead band width is controlled, and the damping force is controlled based on this control signal.

The suspension control device of the second invention having the above structure controls the dead band width of the sprung mass velocity output by the sprung mass velocity measuring means in accordance with at least one of the road surface condition vehicle speed and other running conditions. However, the controller outputs a control signal based on a speed ratio, which is a ratio of the sprung speed whose dead band width is controlled to the relative speed, and the damping force is controlled based on this control signal.

[0009]

The suspension control device of the first aspect of the present invention, which has the above-described operation, controls the dead band width of the relative speed according to at least one of the road surface condition, the vehicle speed, and other running conditions. It is possible to optimally control the damping force according to changes in the vehicle speed and other running conditions, and it is possible to solve the control problems.

Since the suspension control device of the second invention having the above-mentioned operation controls the dead band width of the sprung speed in accordance with at least one of the road surface condition, the vehicle speed and other running conditions, the road condition, the vehicle speed It is possible to optimally control the damping force according to other changes in the running state, and it is possible to solve the control problem.

[0011]

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

(First Embodiment) The suspension control device of the first embodiment performs skyhook control as disclosed in Japanese Patent Application Laid-Open No. 3-276806. As shown in FIGS. A sprung speed measuring means 1 having acceleration sensors 10A to 10C for detecting vertical accelerations Z1 to Z3, and a displacement sensor for detecting vertical displacement amounts Y1 to Y4 of the sprung member. 20A ~
Relative speed measuring means 2 having 20D, which measures the relative speed between the sprung and unsprung parts, and the sprung speed and the relative speed are mode-converted and then inversely converted again to determine the state of the road surface on which the vehicle is running. A controller 3 for controlling the dead band widths of the sprung speed and the relative speed that are inversely converted according to the determined road surface state to obtain a speed ratio and output a control signal;
It is composed of a cylinder piston device 51 of an absorber 50 of a suspension mechanism and an actuator 4 for controlling an opening area of a variable throttle mechanism 53 arranged between an accumulator 52 based on a control signal.

The sprung speed measuring means 1 is an acceleration sensor 10A, 10B, 10C arranged on sprung members (not shown) of the left and right front wheels and the left rear wheel in a positional relationship as shown in FIG.
And 20H of the acceleration signal detected by each acceleration sensor
Low-pass filter 11 that outputs only frequency components below _Z
And an integrator 12 that integrates the acceleration signal output by the low-pass filter 11 and outputs the sprung mass velocity.

Each acceleration sensor 10A, 10B, 10C
Is a vibrating piece 10E having a cantilever structure with one end fixed as shown in FIG. 4, a weight 10W is fixed to the other end of the vibrating piece 10E, and the strain gauge 10G is applied to a portion close to one end of the vibrating piece 10E. The strain associated with the movement of the weight 10W according to the existing acceleration is output as an electrical signal. Left and right front wheel sensors 10
The acceleration of the right rear wheel is estimated from the acceleration signals of A, 10B and the left rear wheel, and one acceleration sensor is omitted.

The relative velocity measuring means 2 is a displacement sensor 2 composed of a potentiometer inserted between the sprung members of each wheel in a positional relationship as shown in FIG.
And 0A～20D, a low-pass filter 21 for outputting only 20H _Z following frequency components of the displacement signal each displacement sensor detects, by outputting the difference for each predetermined time displacement signal low-pass filter 21 is output, the differential And a differentiator 22 which outputs a relative speed.

In each of the displacement sensors 20A to 20D, as shown schematically in FIG. 5, the upper end 2U of the first member 2F is fixed to the sprung member and the lower end 2D of the second member 2S is the sprung member. It is composed of a rotary potentiometer which is fixed and arranged in the first member 2F, and when the distance between the sprung members changes, the first and second members 2
The angular relationship between F and 2S changes, the position of the contact of the potentiometer changes, and the relative displacement is output as a voltage signal.

As shown in FIG. 1, the controller 3 includes a first mode conversion circuit 31 for mode conversion of sprung mass velocity and then mode reverse conversion, and a second mode conversion circuit 31 for mode conversion of relative velocity and second mode conversion. A mode conversion circuit 32 and a first dead zone setting circuit 33 that sets a dead zone to the sprung speed that has undergone mode inverse conversion output from the first mode conversion circuit 31.
And a second dead zone setting circuit 34 for setting a dead zone to the relative speed that has been subjected to the mode inverse conversion output from the second mode conversion circuit 32, and travels based on a signal from the second mode conversion circuit 32. A road surface condition determination circuit 35 that determines the condition of the road surface and outputs a signal for controlling the dead band widths of the first and second dead band setting circuits, and the sprung speed in which the width of the dead band is controlled according to the condition of the road surface. And a relative speed, the speed ratio circuit 36 for calculating a target damping force, and the gain circuit for adjusting the skyhook gain for determining the target damping force according to the road surface state based on the output of the road surface state determining circuit 35. 37, a vehicle speed circuit 38 that outputs a stepwise target damping force in accordance with the vehicle speed signal from the vehicle speed sensor 5, and an eye based on the adjusted speed ratio of the skyhook gain output from the gain circuit 37. It is made of the maximum value circuit 39 for outputting a target damping force larger the target damping force outputted from the damping force and the vehicle speed circuit 38.

The first mode conversion circuit 31 mode-converts the sprung mass velocity into heave, pitch, roll, and warp mode components by the mode conversion circuit 31A, and the weighting circuit 31B appropriately weights K _H for each mode. K _P ,
After K _R and K _W are added, the heave, pitch, roll, and warp mode components respectively weighted by the mode inverse conversion circuit 31C are inversely converted and the weighted sprung mass velocity is output.

The second mode conversion circuit 32 uses the mode conversion circuit 32A to heave, pitch, roll,
Mode conversion is performed on each mode component of the warp, and appropriate weighting K _H , K is applied to each mode component as in the first mode conversion circuit.
_{After P} , K _R , and K _W , the heave, pitch, roll, and warp mode components respectively weighted by the mode inversion conversion circuit 32C are inversely converted and the weighted relative velocity is output.

The road surface state discrimination circuit 35, a low pass filter 35A for outputting 3H _Z following the low frequency component of the output of the mode components of heave of the relative speed mode conversion circuit 32A of the second mode converter 32 outputs a high pass filter 35B for outputting 3H _Z or more high-frequency components of the mode component of the relative velocity of the warp where the mode conversion circuit 32A outputs, when the low-frequency and high-frequency components are not both exceed the threshold smooth road , When the low frequency component exceeds the threshold value, the undulation path, when the high frequency component exceeds the threshold value, the bad path, and when both the low frequency and high frequency components both exceed the threshold value, the compound path is determined. Then
And a determination circuit 35C for outputting a signal for controlling the dead zone width and a skyhook gain signal.

The first dead zone setting circuit 33 uses the weighted sprung speed output from the first mode conversion circuit 31 based on the control signal from the judgment circuit 35C of the road surface condition judgment circuit 35 to indicate the broken line arrow in FIG. As shown in, the dead zone having a controlled width is to set a dead zone having a value of zero.

The second dead zone setting circuit 34 indicates the weighted relative speed output from the second mode conversion circuit based on the control signal from the judging circuit 35C of the road surface condition judging circuit 35 as indicated by the broken line in FIG. The dead zone of the width controlled to set the dead zone which takes a positive or negative constant value.

The speed ratio circuit 36 divides the sprung mass speed in which a dead band having a width controlled by the first and second dead band setting circuits is set by the difference between the sprung mass speed and the relative speed. Then, the speed ratio is obtained and the target damping force is calculated.

The gain circuit 37 multiplies the target damping force based on the speed ratio output by the speed ratio circuit 36 by the skyhook gain signal output by the road surface state determination circuit 35 to adjust the gain.

The maximum value circuit 39 compares the target damping force multiplied by the skyhook gain with the stepwise target damping force output by the vehicle speed circuit 38 based on the magnitude of the vehicle speed signal,
For example, the target damping force multiplied by the larger skyhook gain is output as a control signal.

The actuator 4 drives the drive circuit 41 for amplifying the control signal from the maximum value circuit 39 of the controller 3 and the drive circuit 41 for controlling the opening area of the variable diaphragm mechanism 53 which determines the damping force by the drive signal from the drive circuit 41. And part 42.

As shown in FIG. 8, the drive unit 42 is arranged between the cylinder piston device 51 and the accumulator 52 of the absorbers 50A to 50D of the suspension mechanism for each wheel, and is a variable throttle mechanism arranged in the case body. 53 is formed integrally with the valve member 53V, and by rotating the valve member 53V, the positional relationship with the orifice 53O, which is formed in the inner cylinder 53I so that the facing interval changes in the circumferential direction, is changed. , A configuration for controlling the opening area.

The suspension control device of the first embodiment having the above-mentioned structure is provided with an acceleration sensor 10 as shown in FIG.
A, 10B and 10C detect sprung acceleration, displacement sensors 20A to 20D detect vehicle height, sprung speed measuring means integrates sprung acceleration to measure sprung speed, and relative speed measuring means. The vehicle height is differentiated to measure the relative speed, and the first and second mode conversion circuits 31 and 32 are
The mode components are converted into heave, pitch, roll, and warp mode components and weighted respectively, and then mode inverse conversion is performed to convert the sprung mass velocity and the relative velocity, and the road surface condition determination circuit 35 determines that the road surface condition is bad. Road, good road, compound road, or swell road is discriminated and a dead zone width control signal and a skyhook gain signal are output, and the first and second dead zone setting circuits 33 and 34 are based on the dead zone width control signal. The dead band having a width is set to the sprung speed and the relative speed, and the sprung speed in which the dead band having the width is set by the speed ratio circuit 36 is divided by the difference between the sprung speed and the relative speed. The target damping force is calculated by calculating the speed ratio.

The device of the first embodiment further includes a gain circuit 3
The target damping force is multiplied by the skyhook gain according to the state of the road surface by 7, and the maximum value circuit 39 is used by the vehicle speed circuit 38.
Is output as a control signal in comparison with the stepwise target damping force output by the drive circuit 41. The drive circuit 41 of the actuator 4 amplifies this control signal to output a drive signal, which is driven by this drive signal. The section rotates the valve member 53V of the variable throttle mechanism 53 to control the opening area and realize the target damping force of the absorber 50.

The suspension control device of the first embodiment having the above-mentioned operation controls the width of the dead zone of sprung speed and relative speed according to the condition of the road surface, that is, the dead zone is narrowed on a good road, In this case, since the width of the dead zone is widened, there is an effect of solving the problem that unnecessary control is performed on a bad road and required control is not performed on a good road as in the conventional device.

Further, in the first embodiment, the value in the dead zone is set to zero at the sprung speed and the value in the dead zone is set to a positive or negative constant value at the relative speed, so that the speed ratio becomes infinite. It has the effect of preventing chattering.

Further, the device of the first embodiment has a speed ratio circuit 36.
The gain circuit 37 multiplies the signal for determining the target damping force determined by the above with the skyhook gain on the basis of the determination result of the road surface state to enable the setting of the damping force according to the road surface state, and is determined by the vehicle speed. Since the comparison is made with the target damping force and the maximum value is adopted, it is possible to set the target damping force according to the vehicle speed with priority over the setting of the target damping force according to the speed ratio.

(Second Embodiment) As shown in FIGS. 9 and 10, the suspension control device of the second embodiment is different only in that the width of the dead zone of sprung speed and relative speed is controlled according to the vehicle speed. Unlike the first embodiment, the width of the dead zone can be widened at low speed and the width of the dead zone can be narrowed at high speed, and unnecessary control at low speed can be prevented and necessary control at high speed can be achieved. Play.

(Third Embodiment) As shown in FIGS. 11 and 12, the suspension control device of the third embodiment controls the widths of the dead zones of sprung speed and relative speed according to both the road surface condition and the vehicle speed. Only the point is different from the above-mentioned embodiment, and it becomes possible to control the width of the dead zone when either the road surface state or the vehicle speed outputs the control signal, and both the road surface state and the vehicle speed output the control signal. When output, the operation and effect that the width of the large dead zone corresponding to both control signals can be controlled can be obtained.

The embodiments described above are merely examples for the purpose of explanation, and the present invention is not limited to them. Those skilled in the art will recognize from the claims, the detailed description of the invention and the description of the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

The above-described first embodiment is described as an example, and it is not possible to multiply the skyhook gain based on the road surface condition or to compare the vehicle speed with the stepwise target damping force based on the vehicle speed in the maximum value circuit. The present invention can be omitted.

Further, in the present invention, means for calculating the target damping force based on the lateral G acting on the vehicle or the steering angle is added to the first embodiment described above, and the lateral G or the steering angle is calculated in the maximum value circuit. If the target damping force based on it is the maximum, this also makes it possible to determine the control signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment device of the present invention.

FIG. 2 is a perspective view showing an arrangement mode of the first embodiment device in a vehicle.

FIG. 3 is a chart showing the main control flow of the first embodiment device.

FIG. 4 is a cross-sectional view showing an acceleration sensor of the first embodiment device.

FIG. 5 is a lateral view showing the displacement sensor of the first embodiment device laterally.

FIG. 6 is a diagram showing a dead zone of sprung speed.

FIG. 7 is a diagram showing a dead zone of relative velocity.

FIG. 8 is a cross-sectional view showing an actuator of the first embodiment device.

FIG. 9 is a block diagram showing a second embodiment device.

FIG. 10 is a chart showing a main control flow of the second embodiment device.

FIG. 11 is a block diagram showing a device of a third embodiment.

FIG. 12 is a chart showing a main control flow of the third embodiment device.

FIG. 13 is a diagram showing a dead zone of a conventional device.

[Explanation of symbols]

 1 sprung speed measuring means 2 relative speed measuring means 3 controller 4 actuator 10A, 10B, 10C acceleration sensor 11, 21 low-pass filter 12 integrator 20A, 20B, 20C, 20D displacement sensor 22 differentiator 31 first mode conversion circuit 32 Second mode conversion circuit 33 First dead zone setting circuit 34 Second dead zone setting circuit 35 Road surface state determination circuit 36 Speed ratio circuit 37 Gain circuit 38 Vehicle speed circuit 39 Maximum value circuit 41 Driving circuit 42 Driving unit 50A, 50B , 50C, 50D absorber 51 cylinder piston device 52 accumulator 53 variable throttle mechanism 53I inner cylinder 53O orifice 53V valve member

Front page continuation (72) Inventor Satoshi Onozawa 2-1-1 Asahi-cho, Kariya city, Aichi Aisin Seiki Co., Ltd. (72) Inventor Kunihiro Kawahara 1-town Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd.

Claims (2)

[Claims] 1. A wheel support member is provided between the vehicle body and the vehicle body,
In a suspension control device that controls a damping force according to a drive amount by a drive mechanism, a sprung speed measuring means for measuring sprung speed, a relative speed measuring means for measuring a relative speed between sprung and unsprung, and a road surface. The dead band width of the relative speed output by the relative speed measuring means is controlled according to at least one of the state, the vehicle speed, and other running states, and the ratio of the sprung speed and the dead band width is the controlled relative speed. A suspension control device comprising: a controller that outputs a control signal based on a speed ratio. 2. Provided between the wheel support member and the vehicle body,
In a suspension control device that controls a damping force according to a drive amount by a drive mechanism, a sprung speed measuring means for measuring sprung speed, a relative speed measuring means for measuring a relative speed between sprung and unsprung, and a road surface. The dead band width of the sprung speed output by the sprung speed measuring means is controlled according to at least one of the state, the vehicle speed, and other running states, and the dead band width is controlled to be a ratio between the sprung speed and the relative speed. And a controller that outputs a control signal based on the speed ratio.