JP4527658B2 - Suspension device - Google Patents

Description

  The present invention relates to a suspension device that is provided between a wheel of an automobile or the like and a vehicle body and that controls a damping force against vertical vibration between the wheel and the vehicle body.

Conventionally, this type of suspension device includes a spring device that absorbs an impact received from a road surface and enhances riding comfort, and a shock absorber that generates a damping force against vertical vibration of the spring device.
Some of these suspension devices also have a function of adjusting the height of the vehicle body relative to the wheels, that is, the vehicle height. For example, in the suspension device disclosed in Patent Document 1, a shock absorber is used to perform vehicle vibration suppression control and roll suppression control as well as vehicle height adjustment control. If vehicle height adjustment control is performed while performing vibration suppression control or roll suppression control of the vehicle, these controls interfere with each other and no good control is performed. The control gain for performing high adjustment control is adjusted. In other words, when the vehicle speed is high, the vehicle height adjustment control gain is set low to slow down the vehicle height adjustment speed, and when the vehicle speed is low, the vehicle height adjustment control gain is set high to increase the vehicle height adjustment speed, thereby suppressing vibration. This prevents interference with control and roll suppression control.
JP-A-4-85126

However, in this patent document 1, since the vehicle height adjustment control gain is uniquely set according to the vehicle speed, for example, when the vehicle speed is low, the vehicle height adjustment cannot be delayed, and the vehicle speed is high. Sometimes vehicle height adjustment cannot be done quickly.
Therefore, a large restriction is imposed on the vehicle height adjustment control side, and flexible vehicle height adjustment control cannot be performed.
As a result, it cannot be said that the interference between the vibration suppression control and the vehicle height adjustment control is satisfactorily suppressed.

  An object of the present invention is to address the above-described problem, and an object of the present invention is to satisfactorily suppress interference between vibration suppression control and vehicle height adjustment control.

  In order to achieve the above object, the present invention is characterized by an absorber that generates a damping force against vertical vibration between a wheel and a vehicle body, a traveling state sensor that detects a traveling state of the vehicle, and a traveling state sensor. Filter means for removing noise from the detection signal; Absorber control means provided between the wheel and the vehicle body for adjusting the damping force of the absorber based on the detection signal input via the filter means; the wheel and the vehicle body And a vehicle height control means for adjusting the vehicle height of the vehicle body supported by the support means, wherein the vehicle height control is provided. Vehicle height adjustment detecting means for determining whether or not the vehicle height is being adjusted by the means, and when the vehicle height is being adjusted, the noise removal characteristic of the filter means is adjusted so that the vehicle height is being adjusted. It lies in having a normal filter characteristic changing means for changing relative characteristics when household.

According to the present invention configured as described above, the running state of the vehicle (for example, vertical vibration of the vehicle body or the wheel) is detected by the running state sensor, noise is removed from the detection signal by the filter means, and this noise is removed. The damping force of the absorber is adjusted based on the detected signal. When the vehicle height adjustment control is being performed, the noise removal characteristic of the filter means is changed.
For example, a high-pass filter is provided as the filter means, and the cutoff frequency of the high-pass filter is changed depending on whether or not the vehicle height adjustment control is performed.

In general, when the optimum cutoff frequency is set in the filter means so as to extract only the vertical vibration component of the wheel or vehicle body to be suppressed from the detection signal of the running state sensor, the vehicle height adjustment is not possible with the frequency characteristic of the filter means. Vibrations that occur when performed may not be eliminated. That is, during vehicle height adjustment, vibrations with a frequency higher than the cutoff frequency may be generated.
Therefore, if the vehicle height adjustment control is performed as it is, the absorber operates so as to suppress vibration during the vehicle height adjustment, and smooth vehicle height adjustment cannot be performed.
Therefore, at the time of vehicle height adjustment control, the characteristics of the filter means are changed so as to remove vibrations generated during vehicle height adjustment as noise. For example, the cut-off frequency of the high pass filter is set to be higher than normal (when vehicle height adjustment control is not performed).

As a result, even if the vehicle height adjustment control is performed during the vibration suppression control of the vehicle, the vibration generated during the vehicle height adjustment control is removed as noise, so the absorber operates to suppress the vehicle height adjustment control. Thus, the vibration suppression control and the vehicle height adjustment control can be performed satisfactorily without interfering with each other.
As a result, the reliability of vehicle vibration suppression control and vehicle height adjustment control is improved.
An absorber that generates a damping force against vertical vibration between the wheel and the vehicle body may also be used as the support means.

  Another feature of the present invention is that the filter characteristic changing means determines a noise removal characteristic of the filter means based on the vehicle height adjustment time.

According to this, since the noise removal characteristic of the filter unit is changed based on the adjustment time of the vehicle height, the filter characteristic is not changed more than necessary, and the reliability of the vehicle vibration suppression control by the absorber is further improved. .
For example, when the vehicle height adjustment time (the time required for one vehicle height adjustment) is slow, the vibration generated during vehicle height adjustment has a low frequency, and therefore noise removal of the filter means during normal times is performed. Can be cut with characteristics.
Therefore, in a case where interference can be prevented without changing such noise removal characteristics, optimal vibration suppression control of the vehicle by the absorber can be continued without changing the noise removal characteristics of the filter means.

Another feature of the present invention is provided with a sprung vibration detecting means for detecting a sprung vibration of the vehicle, wherein the filter characteristic changing means has the sprung vibration at a predetermined level or more during the adjustment of the vehicle height. When this is detected, the noise removal characteristic of the filter means is returned to the normal characteristic when the vehicle height is not being adjusted.

  According to this, when it is detected that the sprung vibration (vibration of the vehicle body portion elastically supported by the support means) exceeds a predetermined level during the adjustment of the vehicle height, the noise removal characteristic of the filter means is changed to the normal characteristic. Therefore, priority can be given to vibration suppression control by the absorber. As a result, when the vehicle vibrates greatly, the vibration suppression control performance can be prevented from being lowered even during the vehicle height adjustment.

  Hereinafter, a suspension device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 schematically shows the system configuration of the suspension device according to the embodiment.

This suspension device includes four sets of suspension bodies 10FL, 10FR, 10RL, 10RR provided between the wheels WFL, WFR, WRL, WRR and the vehicle body B, and the operations of the suspension bodies 10FL, 10FR, 10RL, 10RR. And a suspension control device 50 for controlling the suspension.
Hereinafter, the four sets of the suspension bodies 10FL, 10FR, 10RL, and 10RR and the wheels WFL, WFR, WRL, and WRR are simply collectively referred to as the suspension body 10 and the wheels W unless particularly distinguished from front, rear, left, and right.

As shown in FIG. 2, the suspension body 10 is provided between the lower arm LA that supports the wheel W and the vehicle body B, and absorbs the impact received from the road surface by utilizing the elasticity (compressibility) of air to improve the ride comfort. An air spring device 20 (which corresponds to the support means of the present invention) that elastically supports the weight of the vehicle while increasing, and an electromagnetic actuator 30 (this book) that functions as a shock absorber that generates a damping force against vertical vibration of the air spring device 20 Equivalent to the absorber of the invention).
Hereinafter, the side supported by the air spring device 20, that is, the vehicle body B side is referred to as “sprung”, and the side that supports the air spring device 20, that is, the wheel W side is referred to as “unsprung”.

The electromagnetic actuator 30 includes an outer cylinder 31 and an inner cylinder 32 that are arranged coaxially, a ball screw mechanism 35 provided inside the inner cylinder 32, and an electric motor 40 that operates the ball screw mechanism 35.
The outer cylinder 31 and the inner cylinder 32 are constituted by coaxial different diameter pipes, and the outer cylinder 31 is provided on the outer periphery of the inner cylinder 32 so as to be slidable in the axial direction. In the figure, reference numerals 33 and 34 denote bearings that slidably support the inner cylinder 32 in the outer cylinder 31.

  The ball screw mechanism 35 includes a ball screw 36 that rotates by a rotating operation of the electric motor 40, and a ball screw nut 39 that has a female screw portion 38 that engages with a male screw portion 37 formed on the ball screw 36. The ball screw nut 39 is restricted by a rotation stopper (not shown) so that it cannot rotate. Therefore, in this ball screw mechanism 35, the rotational motion of the ball screw 36 is converted into the linear motion of the ball screw nut 39 in the vertical axis direction. Conversely, the linear motion of the ball screw nut 39 in the vertical axis direction is converted to the ball screw 35. Is converted into a rotational motion.

  The lower end of the ball screw nut 39 is fixed to the bottom surface of the outer cylinder 31. When the ball screw nut 39 moves up and down by the rotation of the electric motor 40, the outer cylinder 31 is pushed down or pulled up. Conversely, when an external force is applied to the ball screw 36 to move the outer cylinder 31 in the axial direction, the ball screw 36 rotates to rotate the electric motor 40. At this time, regenerative power is generated by the rotation of the electric motor 40.

  The upper end of the inner cylinder 32 is fixed to the mounting plate 41. The mounting plate 41 is fixed to the motor casing 42 of the electric motor 40, and the ball screw 36 is inserted through a through hole 43 formed in the center thereof. The ball screw 36 is connected to the motor shaft in the motor casing 42 and is rotatably supported by a bearing 44 in the inner cylinder 32.

When the wheel W moves up and down while the vehicle is running, the outer cylinder 31 slides in the axial direction with respect to the inner cylinder 32, and the ball screw nut 39 moves up and down with respect to the ball screw 36 to move the ball screw 36. Rotate. For this reason, the electric motor 40 rotates and acts as a generator. Accordingly, a damping force is generated by the resistance force generated for the power generation.
Further, by energizing the electric motor 40 with the battery 60, the ball screw mechanism 35 can be expanded and contracted to give a propulsive force to the outer cylinder 31, and a predetermined damping force can be generated against the vertical vibration of the vehicle body B. In either case, the damping force can be adjusted by adjusting the magnitude of the current flowing through the electric motor 40.

  The air spring device 20 is provided on the outer periphery of the electromagnetic actuator 30, and includes a cylindrical upper case 21 surrounding the outer periphery of the motor casing 42, a lower case 22 surrounding the outer peripheral surface of the outer cylinder 31, both cases 21, And a diaphragm 23 mainly composed of rubber that connects the two cylinders 22 in an airtight state. These cases 21 and 22 and the diaphragm 23 form an air chamber 24 on the outer periphery of the outer cylinder 31, the inner cylinder 32, and the motor casing 42. . The upper case 21 and the lower case 22 are hermetically welded and fixed to the outer peripheral surfaces of the motor casing 42 and the outer cylinder 31, respectively, so that the air chamber 24 is hermetically sealed.

The upper case 21 is provided with a nozzle 25 as a supply / discharge port for supplying and exhausting air into the air chamber 24. As shown in FIG. 1, a supply / exhaust pipe 81 serving as a high-pressure air flow path from a supply / exhaust device 80 controlled by the suspension control device 50 is connected to the nozzle 25. The air pressure in 24 is adjusted.
The suspension body 10 configured in this manner is attached to the vehicle body B via the upper support 26 made of an elastic material on the upper surface of the upper case 21.

Next, the suspension control device 50 that controls the operation of the suspension body 10 will be described.
FIG. 3 is a block diagram showing the function of the suspension control device 50.

The suspension control device 50 includes an absorber control device 51 that drives and controls the electromagnetic actuator 30 as a shock absorber, and a vehicle height adjustment control device 52 that drives and controls the air spring device 20 to maintain the vehicle height at a predetermined value. Each major part is constituted by a microcomputer.
Moreover, the absorber control device 51 secures the driving stability by maintaining the good vehicle posture and the riding comfort control unit 51a that calculates the control amount of the electromagnetic actuator 30 so as to ensure the good riding comfort. Thus, it is roughly divided into a operability control unit 51b that calculates the control amount of the electromagnetic actuator 30.
The absorber control device 51 corresponds to the absorber control means of the present invention, and the vehicle height adjustment control device 52 corresponds to the vehicle height control means of the present invention.

  In order to perform such various controls, output signals from various sensors are input to the suspension control device 50. Hereinafter, the sensors provided for each wheel W will be described with the same reference numerals because there is no need to distinguish them.

  The suspension control device 50 includes a sprung acceleration sensor 61 (hereinafter referred to as a sprung G sensor 61) that detects a vertical acceleration on a spring as a sensor provided for each wheel W, and a vertical direction below the spring. An unsprung acceleration sensor 62 (hereinafter referred to as unsprung G sensor 62), a vehicle height sensor 63 for detecting a vehicle height from, for example, a relative position in the vertical direction of the spring with respect to the unsprung mass, and an air spring device 20 is connected to a pressure sensor 82 for detecting the pressure in the high-pressure air supply circuit. Further, as a sensor provided in each vehicle, a vehicle speed sensor 65 for detecting the traveling speed of the vehicle, A lateral acceleration sensor 66 (hereinafter referred to as a lateral G sensor 66) that detects acceleration is connected.

  The suspension control device 50 connects a motor drive circuit 55 that drives and controls the electromagnetic actuator 30 based on detection signals of these various sensors and a supply / discharge device 80 that supplies compressed air to the air spring device 20.

  The motor drive circuit 55 that controls the drive of the electric motor 40 of the electromagnetic actuator 30 constitutes a three-phase inverter circuit. The three-phase electromagnetic coil CL1 of the electric motor 40 (a three-phase brushless motor is used in this embodiment), The switching elements SW11, SW12, SW21, SW22, SW31, and SW32 respectively correspond to CL2 and CL3. These switching elements SW 11, SW 12, SW 21, SW 22, SW 31, SW 32 are on / off controlled by signals from the suspension control device 50. The motor drive circuit 55 is provided with current sensors 56a, 56b, and 56c for detecting the value of the current flowing through the electric motor 40 in each phase. Hereinafter, the three current sensors 56a, 56b, and 56c are collectively referred to as a current sensor 56.

In this motor drive circuit 55, by controlling the duty ratio of the switching elements SW11, SW12, SW21, SW22, SW31, SW32 (PWM control), the energization amount from the battery 60 to the electric motor 40 or the electric motor 40 to the battery 60 is controlled. Controls the amount of regenerative power sent to the side.
Since this motor drive circuit 55 controls the drive of the electric motor 40 of the electromagnetic actuator 30 by the control signal from the absorber control device 51, it constitutes the absorber control means of the present invention together with the absorber control device 51.

  The supply / discharge device 80 includes a compressor (not shown) that compresses air to generate high-pressure air. In addition, a supply / exhaust pipe 81 serving as a high-pressure air supply / exhaust path from the supply / exhaust apparatus 80 to each air spring apparatus 20 includes an electromagnetic valve 83 for opening / closing the flow path and a pressure sensor 82 for detecting the pressure in the flow path. Is provided. The vehicle height adjustment control device 52 adjusts the pressure in the air chamber 24 of the air spring device 20 to maintain the vehicle height at the target position by controlling the operation of the compressor and the electromagnetic valve 83 of the supply / discharge device 80. .

Next, ride comfort control, steering stability control (hereinafter referred to as steering control) performed by the absorber control device 51, and vehicle height control performed by the vehicle height adjustment control device 52 will be described.
FIG. 4 shows a control routine for ride comfort control, steering stability control executed by the absorber control device 51, and a vehicle height control routine executed by the vehicle height adjustment control device 52, each in a memory element (not shown) of each control device. It is stored as a control program.

In the ride control unit 51a of the absorber control device 51, the vertical acceleration signals from the unsprung G sensor 62 and the unsprung G sensor 61 are input for each wheel (S1), and the acceleration signals are integrated (S2). The low-frequency vibration component that becomes noise is cut by high-pass filter processing (S3), and the unsprung speed V1 and the sprung speed V2 are obtained (S4). Then, the sum (K1 · V1 + K2 · V2) of the value (K1 · V1) obtained by multiplying the unsprung speed V1 by the control gain K1 and the value (K2 · V2) obtained by multiplying the unsprung speed V2 by the control gain K2 is multiplied. Calculated as a comfort control amount (S5). This ride comfort control amount is calculated independently for each wheel W.
The unsprung G sensor 62 and the unsprung G sensor 61 correspond to the running state sensor of the present invention, and the filtering process in step S3 corresponds to the filter means of the present invention.

  The process of step S3 is for removing noise included in the acceleration signals from the unsprung G sensor 62 and the unsprung G sensor 61, that is, a signal component (low frequency vibration component) that is not a target of vibration suppression control. In this process, a cutoff frequency CUTf1 suitable for vibration suppression control is set as shown by the filter characteristic F1 in FIG.

However, during vehicle height adjustment control, vibration higher than the cut-off frequency CUTf1 is generated along with the vehicle height adjustment operation. Therefore, in this filter characteristic F1, riding comfort control works to suppress the vehicle height adjustment operation. The vehicle height cannot be adjusted smoothly.
Therefore, in the riding comfort control unit 51a, as will be described later, the filter characteristics are changed, that is, a filter in which the cutoff frequency of the high-pass filter is set to a value higher than the normal frequency CUTf1 (for example, the cutoff frequency CUTf2). Switch to characteristic F2. FIG. 11 shows the characteristics of the integral filter processing combining step S2 and step S3.

On the other hand, the stability control unit 51b of the absorber control device 51 inputs a lateral acceleration signal from the lateral G sensor 66 as shown in the middle part of FIG. 4 (S6), and applies a control gain K3 to the lateral acceleration YG. The multiplied value (K3 · YG) is calculated as the steering control amount (S7). The control amount in this case is the same on the front wheel side and the rear wheel side, but the sign is reversed on the left wheel side and the right wheel side. That is, the control gain on the right wheel side is set to -K3 with respect to the control gain K3 on the left wheel side.
Then, the sum of the ride comfort control amount and the operability control amount calculated for each wheel is calculated as the control amount of each electromagnetic actuator 30 (S8), and the energization amount according to the calculated control amount. Drive control of the electric motor 40 of the electromagnetic actuator 30 is performed (S9).

  In this case, the switching elements SW11, SW12, SW21, SW22, SW31, and SW32 of the motor drive circuit 55 are opened and closed at a duty ratio corresponding to the control amount, but the regenerative current from the electric motor 40 is compared with the target energization amount. If the regenerative current is larger, the regenerative current flows to the battery 60 side, and conversely, if the regenerative current from the electric motor 40 is less than the target energization amount, the regenerative current is energized from the battery 60 to the electric motor 40.

  Further, the vehicle height adjustment control device 52 performs vehicle height control by PID control. That is, as shown in the lower part of FIG. 4, a preset target vehicle height H0 is read (S10), the actual vehicle height Hx is detected by the vehicle height sensor 63 (S13), and this target vehicle height H0 is detected. The deviation ΔH from the vehicle height Hx is multiplied by a control gain K4 (here, the control gains of the proportional term, differential term, and integral term are collectively referred to as K4) (S11), and the supply / discharge device according to the value K4 · ΔH The 80 electromagnetic valve 83 is opened and closed (S12).

  According to such a suspension control device 50, the impact received from the road surface by the air spring device 20 is absorbed to enhance the ride comfort and the vehicle body B is supported at a predetermined vehicle height position, while the vertical vibration of the air spring device 20 is prevented. The damping force for the vertical vibration is adjusted by the electromagnetic actuator 30 so as to obtain good riding comfort and maneuverability.

  The vehicle height may be adjusted by the electromagnetic actuator 30 (absorber), and the vehicle height may be maintained only by the air spring device 20 after the vehicle height is adjusted. That is, the adjustment operation up to the target vehicle height is performed by the electromagnetic actuator 30, and when the vehicle height adjustment is completed, the vehicle height maintenance by the electromagnetic actuator 30 is terminated and the vehicle height maintenance by only the air spring device 20 is switched. The power consumption necessary for maintaining the vehicle height may be suppressed.

Next, the filter characteristic changing process executed by the absorber control device 51 will be described. FIG. 5 shows a filter characteristic change control routine executed by the absorber control device 51, and is stored as a control program in a storage element (not shown) in the absorber control device 51.
This control routine is performed in parallel with the ride comfort control and the maneuverability control. The control routine is activated when the ignition switch is turned on and is repeatedly executed at a predetermined short cycle.

First, it is determined whether vehicle height adjustment control is being performed (S21). That is, the control signal is read from the vehicle height adjustment control device 52 to determine whether or not the vehicle height adjustment control is being executed.
If the vehicle height adjustment control is not in progress, it is next determined whether or not the flag F is set to 1 (S26). This flag F is set to F = 1 when the characteristic of the high-pass filter is changed for vehicle height adjustment control, and is set to F = 0 when this control routine is started. Therefore, in a state in which this control routine is activated, this determination is “NO”, and this control routine is temporarily terminated.

  Since this control routine is repeated at a predetermined short cycle, during the period when the vehicle height adjustment control is not performed, only the determination of steps S21 and S26 is repeated as “NO”, and no substantial processing is performed. And if vehicle height adjustment control is started, judgment of step S21 will be "YES" and the following processes will be performed.

First, it is determined whether or not the flag F is set to 1 (S22). In this case, immediately after the vehicle height adjustment control is started, since F = 0 is set, the determination in step S22 is “NO”, and then the vehicle height adjustment time (frequency) is calculated ( S23).
In the vehicle height adjustment control device 52, the vehicle height adjustment time (the time from the start to the end of the vehicle height adjustment) is set according to the traveling state. For example, as shown in FIG. 6, the vehicle height adjustment time is set longer as the vehicle speed is higher (faster). Further, as shown in FIG. 7, the vehicle height adjustment time is set shorter as the road surface unevenness level is higher. In addition, as shown in FIG. 8, the driver changes the vehicle height in a short time by pressing the high speed button among the buttons provided as vehicle height change operation buttons (not shown), and changes the vehicle height over a long time by pressing the low speed button. To do.

The vehicle height adjustment control device 52 is configured to output vehicle height adjustment time data to the absorber control device 51. Therefore, the absorber control device 51 can obtain the vehicle height adjustment time by inputting the vehicle height adjustment time data output from the vehicle height adjustment control device 52.
Alternatively, the absorber control device 51 may calculate the vehicle height adjustment time by inputting a vehicle speed signal and a road surface unevenness level signal (unsprung G signal).

  Subsequently, the frequency characteristic of the high-pass filter is changed based on the vehicle height adjustment time (S24). That is, the cutoff frequency of the high-pass filter is determined so that the vibration of the vehicle speed adjustment frequency (reciprocal of the vehicle height adjustment time) can be removed. In this case, the cutoff frequency may be obtained from the vehicle height adjustment time data output from the vehicle height adjustment control device 52. However, the vehicle speed signal and the road surface unevenness level signal ( The cut-off frequency may be obtained from the unsprung G signal.

For example, if the vehicle height adjustment time is 2 seconds, the cutoff frequency is set to a predetermined value greater than 0.5 Hz. That is, the cutoff frequency is set to a predetermined frequency higher than the vehicle height adjustment frequency. For example, in FIG. 11, the cutoff frequency CUTf1 at the time of vehicle height adjustment in this case is set to CUTf2 = 0.7 to 0.8 Hz with respect to the cutoff frequency CUTf1 = 0.1 to 0.2 Hz of the normal high-pass filter. Set to.
If the vehicle height adjustment time determined in step S23 is a predetermined time or longer (for example, 10 seconds or longer), vibration due to vehicle height adjustment does not affect the vibration suppression control, that is, the vehicle height adjustment frequency is a high-pass filter. Therefore, the high-pass filter characteristic is not changed.

Subsequently, the flag F is set to 1 (S25), and this control routine is once ended.
Then, this control routine is repeated every predetermined time. If the vehicle height adjustment control is being performed, the high-pass filter characteristic has already been changed. Therefore, the determination in step S22 is “YES, and the processing in steps S23 to S25 is performed. Skip and exit this control routine.

If the vehicle height adjustment control is completed while such a determination is repeated, the determination in step S21 is “NO”, and then the flag F confirmation process in step S26 is performed.
In this case, the flag F is set to 1 until immediately before, and the cut-off frequency of the high-pass filter is set for vehicle height adjustment control. Therefore, in step S27, the frequency characteristic of the high-pass filter is the normal one. (S27). That is, the cutoff frequency of the high pass filter is returned to the normal CUT f1.

  Subsequently, the flag F is set to F = 0 and the control routine is exited. Therefore, thereafter, until the vehicle height adjustment control is started, the determinations in steps S21 and S26 are “NO”, and the high-pass filter characteristic suitable for normal vibration suppression control is maintained.

According to the filter characteristic change control routine of the present embodiment described above, even when the vehicle height adjustment control is performed during the vibration suppression control of the vehicle, the cutoff frequency of the filter is changed and is generated during the vehicle height adjustment control. Since the vibration is removed as noise, the vibration suppression control is prevented from operating so as to suppress the vehicle height adjustment control, and the reliability of the vehicle vibration suppression control is improved. As a result, the vehicle vibration suppression control and the vehicle height adjustment control can be favorably performed without interfering with each other.
Further, since the cutoff frequency of the high-pass filter is set according to the vehicle height adjustment time, the vehicle vibration suppression control is not suppressed more than necessary, and the vehicle height adjustment control can be appropriately achieved. .

  Note that the processing of step S21 performed by the absorber control device 51 described above corresponds to the vehicle height adjustment detection means of the present invention, and the processing of steps S24 and S27 corresponds to the filter characteristic changing means of the present invention.

Next, a first modification of the filter characteristic change control routine will be described. FIG. 12 shows a first modification of the filter characteristic change control routine executed by the absorber control device 51, and is stored as a control program in a storage element (not shown) in the absorber control device 51.
In the first modification, the processes of steps S29 and S30 are added to the control routine of the previous embodiment, and the other processes are the same. Hereinafter, the added process will be described, and other processes will be denoted by the same step numbers in the drawings, and description thereof will be omitted.

In a situation where the vehicle height adjustment control is being performed, in step S29, it is determined based on the detection signal from the sprung G sensor 61 whether or not the sprung acceleration Gux exceeds the reference value Gu0. That is, it is determined whether or not the vibration on the spring is greater than the reference level.
If this determination is “NO”, the process directly proceeds to the process of step S12 described above. If “YES”, that is, if it is determined that the vibration on the spring is larger than the reference level, the vehicle height adjustment control device 52 is determined. In response to this, a command is output to temporarily stop the vehicle height adjustment (S30).

  If the high-pass filter characteristic has already been changed (S26: YES), the frequency characteristic of the high-pass filter is returned to the normal one in step S27 (S27). That is, the cutoff frequency of the high pass filter is returned to the normal CUT f1. In this case, the frequency characteristics of the high-pass filter are gradually returned without returning suddenly. For example, the cut-off frequency of the high pass filter is lowered stepwise.

  According to the first modification of the filter characteristic change control routine described above, when the vehicle vibrates greatly, priority is given to the vehicle vibration suppression control. Therefore, even when the vehicle height is being adjusted, the vibration suppression control performance. Can be avoided. In this case, since the frequency characteristics of the high-pass filter are gradually returned instead of suddenly returning, the vehicle behavior does not change suddenly and the driver does not feel uncomfortable.

Next, modification 2 of the filter characteristic change control routine will be described. FIG. 13 shows a second modification of the filter characteristic change control routine executed by the absorber control device 51 and is stored as a control program in a storage element (not shown) in the absorber control device 51.
In the second modification, step S31 is performed instead of step S30 in the first modification, and the other processes are the same. Hereinafter, the modified process will be described, and the other processes will be denoted by the same step numbers in the drawings and the description thereof will be omitted.

When the vehicle height adjustment control is being performed and the sprung acceleration Gux exceeds the reference value Gu0, the process proceeds to step S31, where the vehicle height adjustment controller 52 gradually increases the vehicle height. Command to raise. In this case, the rising speed of the vehicle height is slowed by adjusting the control gain of the PID control performed by the vehicle height adjustment control device 52.
If the high-pass filter characteristic has already been changed (S26: YES), the frequency characteristic of the high-pass filter is returned to the normal one in step S27 (S27). Even in this case, the frequency characteristics of the high-pass filter are gradually returned without being suddenly restored.

  According to the second modification, when the vehicle vibrates greatly, the high-pass filter characteristic is returned to the normal one to give priority to the vehicle vibration suppression control, and in order to gradually increase the vehicle height, the interference with the road surface is reduced. Can be prevented.

Although the suspension device of the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention.
For example, in this embodiment, the electromagnetic actuator 30 is used as a shock absorber for adjusting the damping force, but various types such as a hydraulic control type can be adopted.
In this embodiment, a rotation-linear motion conversion mechanism is employed in which the ball screw 36 is rotated by the electric motor 40 and the ball screw nut 39 is moved up and down in the axial direction. However, a linear solenoid type linear motion motor is employed. It is also possible to adopt an electromagnetic actuator using. For example, this direct acting motor is provided with an electromagnetic coil on the inner peripheral surface of the outer cylinder, and a permanent magnet facing the electromagnetic coil is disposed on the outer peripheral surface of the inner cylinder, and the electromagnetic coil is energized. Axial thrust is generated between the cylinder and the electromotive force is generated in the electromagnetic coil by the axial relative movement of the outer cylinder with respect to the inner cylinder, and a damping force is generated by energizing the electromagnetic coil and generating power. It is.

  In the present embodiment, the air spring device 20 is employed as a support means for elastically supporting the vehicle body, but a shock absorber may also be used as the support means. Further, the support means may be constituted by a spring device using a coil spring, and the vehicle height may be adjusted by a shock absorber.

1 is a system configuration diagram of a suspension device according to an embodiment of the present invention. It is sectional drawing showing schematic structure of a suspension main body. It is a functional block diagram of a suspension control device. It is a flowchart showing a control routine and a vehicle height control routine of riding comfort control, steering stability control. It is a flowchart showing a filter characteristic change control routine. It is explanatory drawing showing the relationship of the vehicle height adjustment time with respect to a vehicle speed. It is explanatory drawing showing the relationship of the vehicle height adjustment time with respect to a road surface state. It is explanatory drawing showing the relationship of the vehicle height adjustment time with respect to button selection. It is explanatory drawing showing a cut-off frequency calculation map. It is explanatory drawing showing the frequency characteristic of a high pass filter. It is explanatory drawing showing the frequency characteristic of a high pass approximate integration filter. It is a flowchart showing the modification 1 of a filter characteristic change control routine. It is a flowchart showing the modification 2 of a filter characteristic change control routine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Suspension main body, 20 ... Air spring apparatus (support means), 30 ... Electromagnetic actuator (absorber), 40 ... Electric motor, 50 ... Suspension control apparatus, 51 ... Absorber control apparatus (absorber control means), 52 ... Vehicle height adjustment Control device (vehicle height control means), 55... Motor drive circuit.

Claims (3)

An absorber that is provided between the wheel and the vehicle body and generates a damping force against vertical vibration between the wheel and the vehicle body;
A driving state sensor for detecting the driving state of the vehicle;
Filter means for removing noise in the detection signal from the running state sensor;
Absorber control means for adjusting the damping force of the absorber based on a detection signal input through the filter means;
A support means provided between the wheel and the vehicle body for supporting the vehicle body so that the vehicle height can be changed;
A suspension device comprising vehicle height control means for adjusting the vehicle height of the vehicle body supported by the support means,
Vehicle height adjustment detection means for determining whether the vehicle height is being adjusted by the vehicle height control means;
Suspension characterized by comprising a filter characteristic changing means for changing a noise removal characteristic of the filter means to a normal characteristic when the vehicle height is not being adjusted when the vehicle height is being adjusted. apparatus.   2. The suspension apparatus according to claim 1, wherein the filter characteristic changing means determines a noise removal characteristic of the filter means based on the vehicle height adjustment time. Comprising sprung vibration detecting means for detecting sprung vibration of the vehicle;
The filter characteristic changing means is a normal characteristic when the vehicle height is not being adjusted when the vehicle height is detected and the sprung vibration is detected to be above a predetermined level. The suspension device according to claim 1 or 2, wherein the suspension device is returned to the position.

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