JP2013049394A - Suspension control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension control device which controls a shock absorber on the basis of speed without an integral error.SOLUTION: A GPS sensor 9 calculates vertical speed information by using a GPS signal from a GPS receiver 8. The riding comfort controller 12 of a controller 10 outputs a control command value based on riding comfort control by using the vertical speed information from the GPS sensor 9 as speed V1 on a spring. Meanwhile, the undulation suppression control part 14 of controller 10 outputs a control command value that suppresses a pitch on the basis of a vehicle state signal which is output by another controller 16. A command value switching part 15 selects and outputs one of the control command value by the riding comfort controller 12 and the control command value by the undulation suppression control part 14, according to the reception state of the GPS receiver 8.

Description

  The present invention relates to a suspension control device preferably used for buffering vibration of a vehicle.

  2. Description of the Related Art Generally, in a vehicle such as an automobile, a suspension control device having a configuration in which a damping force adjustment type shock absorber is provided between a vehicle body and each axle, and a damping force characteristic by the shock absorber is variably controlled according to a control command. Is mounted (see, for example, Patent Documents 1 to 3).

  In this type of conventional suspension control device, for example, an acceleration sensor is used to detect vibrations in the upper and lower directions of the vehicle body, and the damper is controlled to generate a damping force corresponding to the detected vibrations. It is configured to output a command.

JP 2009-83614 A JP 2009-83641 A JP 2009-262926 A

  By the way, in the suspension control device according to the prior art, for example, the speed is calculated by integrating the acceleration obtained from the acceleration sensor, and the buffer is controlled using this speed. However, since the speed obtained by this method is integrated, there is a problem that the accumulated sensor error is added as an integration error. Further, when the road surface is inclined, an offset error is generated in the acceleration itself due to the inclination. Therefore, the offset error is removed by a high-pass filter. However, since all errors cannot be removed even with a high-pass filter, a cumulative error occurs during integration. Furthermore, there is a problem that a phase shift occurs in the signal by using a high-pass filter.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a suspension control device capable of controlling a shock absorber based on a speed without an integration error. It is in.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a GPS receiver that is provided in a vehicle body and receives a signal from a GPS satellite, and an upward and downward direction of the vehicle body using a signal from the GPS receiver. The vehicle body vertical motion calculation means for calculating the motion state of the vehicle body, and the control means for controlling the damping force adjustment type shock absorber based on the motion state of the vehicle body vertical motion calculation means.

  According to the present invention, the motion state of the vehicle body in the upward and downward directions can be calculated using the signal from the GPS receiver, and the buffer can be controlled based on the speed without an integration error.

It is a figure which shows typically the suspension control apparatus by the 1st Embodiment of this invention. It is a block diagram which shows the controller in FIG. It is a flowchart which shows the control content by the controller in FIG. It is a flowchart which shows the content of control calculation execution in FIG. It is a flowchart which shows the content of control calculation execution by the 2nd Embodiment of this invention.

  Hereinafter, a suspension device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the suspension device is applied to a four-wheeled vehicle.

  First, FIG. 1 to FIG. 4 show a first embodiment of the present invention. The vehicle body 1 constitutes a vehicle body. Below the vehicle body 1, for example, left and right front wheels and left and right rear wheels (hereinafter collectively referred to as wheels 2) are provided. The wheels 2 include tires 3. At this time, the tire 3 acts as a spring that absorbs fine irregularities on the road surface.

  The suspension device 4 is provided between the vehicle body 1 and the wheel 2. The suspension device 4 includes a suspension spring 5 (hereinafter referred to as a spring 5) and a damping force adjustment type shock absorber (hereinafter referred to as a shock absorber 6) provided between the vehicle body 1 and the wheel 2 in parallel with the spring 5. ). FIG. 1 illustrates a case where a set of suspension devices 4 is provided between the vehicle body 1 and the wheels 2. However, for example, a total of four suspension devices 4 are individually provided between the four wheels 2 and the vehicle body 1, and only one of these is schematically illustrated in FIG. 1. .

  Here, the shock absorber 6 of the suspension device 4 is configured using a damping force adjusting hydraulic shock absorber. The shock absorber 6 includes a damping force adjusting valve or the like for continuously adjusting the generated damping force characteristic (damping force characteristic) from a hard characteristic (hard characteristic) to a soft characteristic (soft characteristic). An actuator 7 is attached. Note that the damping force adjusting valve may be capable of adjusting the damping force characteristic in two steps or a plurality of steps without being continuous.

  The GPS receiver 8 is provided in the vehicle body 1 and receives a signal (hereinafter referred to as a GPS signal) from a GPS (Global Positioning System) satellite. The GPS receiver 8 is provided with a GPS sensor 9 as vehicle body vertical motion calculation means. The GPS sensor 9 calculates vertical speed information and altitude information based on the reception signal of the GPS receiver 8 as the upward and downward movement states of the vehicle body 1. At this time, the vertical velocity information indicates the vertical movement velocity of the GPS receiver 8 (vehicle body 1), and can be obtained by using, for example, the Doppler effect of the GPS signal. The altitude information indicates the altitude of the vehicle body 1 and can be obtained by determining the three-dimensional position of the GPS receiver 8 based on signals from a plurality of GPS satellites, for example. The GPS sensor 9 then outputs vertical speed information and altitude information to the controller 10 for the suspension device 4. Further, the GPS sensor 9 determines whether or not the GPS receiver 8 can receive a GPS signal, and also outputs a signal corresponding to the determination result to the controller 10.

  The controller 10 is composed of, for example, a microcomputer and constitutes a control means for controlling the shock absorber 6 based on the vertical speed information from the GPS sensor 9. The controller 10 has an input side connected to the GPS sensor 9 and another controller 16 described later, and an output side connected to the actuator 7 of the shock absorber 6 and the like. The controller 10 has a storage unit 10A composed of a ROM, a RAM, and the like, and the storage unit 10A stores processing programs and the like described later shown in FIGS.

  Here, as shown in FIG. 2, the controller 10 includes a relative speed estimation unit 11, a riding comfort control unit 12, a pitch rate estimation unit 13, a swell suppression control unit 14, a command value switching unit 15, and the like.

  The relative speed estimation unit 11 includes, for example, a Kalman filter (observer) to which modern control theory is applied, and acquires vertical speed information output from the GPS sensor 9 as a sprung speed V1, and the sprung speed V1 and the like. Based on the above, the upward and downward relative speed V2 between the vehicle body 1 and the wheel 2 is calculated. The relative speed V2 is fed back to the relative speed estimation unit 11.

  The riding comfort control unit 12 uses a sprung speed V1 (vertical speed information) output from the GPS sensor 9 and a relative speed V2 output from the relative speed estimation unit 11 to determine a predetermined skyhook control theory. A control command value as a control command is output based on

  Specifically, the ride comfort control unit 12 includes, for example, a gain map based on the skyhook control theory indicating the relationship between the sprung speed V1 and the target damping force F, the target damping force F, the relative speed V2, and the control command value. And a damping force map indicating the relationship.

  Therefore, the ride comfort control unit 12 acquires the vertical speed information output from the GPS sensor 9 as the sprung speed V1, and uses the gain map to generate the target damping force that is generated in the shock absorber 6 from the sprung speed V1. F is calculated. At this time, a value obtained by multiplying the sprung speed V1 by a gain is output as the target damping force F so that the target damping force F increases or decreases in proportion to the sprung speed V1.

  When the target damping force F is calculated, the riding comfort control unit 12 variably controls the damping force characteristic of the shock absorber 6 based on the target damping force F and the relative speed V2 using the damping force map, for example, a current command. A control command value such as a value is output. As a result, the generated damping force of the shock absorber 6 is controlled (adjusted) between hardware and software continuously or variably in multiple stages according to the control command value supplied to the actuator 7.

  The pitch rate estimator 13 estimates the pitch motion of the vehicle based on, for example, wheel speed, vehicle speed, engine torque, gear position, brake master cylinder hydraulic pressure, and the like as a vehicle state signal output from the controller 16 described later. Calculate the pitch rate.

  The swell suppression control unit 14 calculates and outputs a control command value for suppressing the pitch based on the pitch rate output from the pitch rate estimation unit 13. Specifically, assuming a system that does not use an acceleration sensor described in, for example, Japanese Patent Application Laid-Open No. 2010-83329, in this system, a control command value for suppressing the pitch is set based on the pitch rate estimated from the vehicle state signal. Output.

  The command value switching unit 15 is, for example, one of a control command value output from the ride comfort control unit 12 and a control command value output from the swell suppression control unit 14 according to the reception state of the GPS receiver 8. Is output to the actuator 7. Specifically, when the GPS receiver 8 can receive a GPS signal, the command value switching unit 15 selects a control command value output from the riding comfort control unit 12. On the other hand, when the GPS receiver 8 cannot receive a GPS signal, the command value switching unit 15 selects a control command value output from the swell suppression control unit 14.

  The other controller 16 is connected to various sensors used for applications other than vehicle vibration control, for example, and constitutes other control means used for control other than the suspension device 4 such as an engine and a brake. The controller 16 outputs, for example, a wheel speed, a vehicle speed, an engine torque, a gear position, a brake master cylinder hydraulic pressure, and the like as a vehicle state signal. The controller 16 is connected to the controller 10 through a CAN (Controller Area Network) or the like. For this reason, the controller 10 acquires a vehicle state signal through CAN.

  In the above-described embodiment, the same damping force command control is performed for all four wheels. However, the ride rate controller 12 estimates and detects the pitch rate of the pitch rate estimator 13 and the roll rate from the controller 16. The four wheels can be controlled individually. That is, assuming that the GPS signal of the GPS receiver 8 is a system that estimates the acceleration of each of the four wheels with one acceleration sensor described in, for example, Japanese Patent Application Laid-Open No. 2009-262926, Can be sought.

  The vehicle suspension control apparatus according to the present embodiment has the above-described configuration. Next, processing for variably controlling the damping force characteristic of the shock absorber 6 using the controller 10 will be described.

  First, when the control process shown in FIG. 3 is started upon receiving power supply accompanying the engine start of the vehicle, the controller 10 is initially set in step 1. Then, in step 2, it is determined whether or not a control cycle of, for example, about 5 to 10 ms has been reached, and the process waits until the control cycle is reached while determining “NO”. On the other hand, if “YES” is determined in step 2 and the control cycle is reached, the process proceeds to the next step 3 to output the control command value calculated in the previous control cycle to the actuator 7, and the actuator 7 of the shock absorber 6. Drive. Thereafter, in step 4, other port outputs such as lamps are performed.

  Next, in step 5, the vertical speed information is read from the GPS sensor 9 as the sprung speed V1, and information such as the vehicle speed and the wheel speed as a vehicle state signal input from another controller 16 by communication is read. . Then, in the next step 6, a control calculation for ride comfort control and a control calculation for swell suppression control are performed from the obtained information to obtain a control command value (current command value) for each control, and GPS reception is performed. One of the control command values is selected according to the reception state of the machine 8.

  The control command value selected in step 6 drives and controls the actuator 7 of the shock absorber 6 in the next step 3 every time the control cycle determined as “YES” in step 2 is reached. Used for. Thereby, the damping force characteristic of the shock absorber 6 is continuously controlled by being variable between a hard characteristic (hard characteristic) and a soft characteristic (soft characteristic).

  Next, the control calculation execution process shown in FIG. 4 will be described. In this control calculation execution process, it is determined in step 11 whether the GPS receiver 8 can receive a GPS signal. If it is determined as “YES” in step 11, the GPS receiver 8 can receive the GPS signal. Therefore, the process proceeds to step 12 to select a control command value output from the riding comfort control unit 12 and return. .

  On the other hand, if “NO” is determined in step 11, the GPS receiver 8 cannot receive a GPS signal, so the process proceeds to step 13, selects a control command value output from the swell suppression control unit 14, and returns. .

  As described above, according to the present embodiment, the GPS sensor 9 uses the GPS signal to calculate the vertical speed information as the motion state of the vehicle body 1 in the upward and downward directions, so that the controller 10 By using the information as the sprung speed V1, ride comfort control for improving the ride comfort of the vehicle is performed. For this reason, the sprung speed V1 used for ride comfort control is not generated by integrating the acceleration as in the prior art, but can be generated directly from the GPS signal, and there is no integration error.

  Further, the controller 10 is configured to control the shock absorber 6 based on the wheel speed information from the other controller 16 when the GPS receiver 8 cannot receive the GPS signal. For this reason, the pitch rate is estimated based on the wheel speed information even when the GPS receiver 8 cannot receive the GPS signal and the vertical speed information cannot be obtained, for example, when a vehicle enters the tunnel. In addition, it is possible to perform swell suppression control that suppresses the pitch.

  Next, FIG. 5 shows a second embodiment of the present invention. The feature of this embodiment is that the controller has a predetermined error between the vehicle speed information calculated by another controller and the vehicle speed information calculated based on the GPS signal even if the GPS receiver can receive the GPS signal. When it is larger than the threshold value, the shock absorber is controlled based on wheel speed information from another controller. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  Here, in the second embodiment, the GPS sensor 9 calculates horizontal speed information as vehicle speed information Vgps based on the GPS signal in addition to the vertical speed information. At this time, the horizontal speed information indicates the moving speed of the GPS receiver 8 (vehicle body 1) in the horizontal direction, and can be obtained using, for example, the Doppler effect of the GPS signal. The horizontal speed information can also be obtained by time differentiation of the horizontal position information obtained from the GPS signal.

  Next, the control calculation execution process shown in FIG. 5 will be described. In this control calculation execution process, it is determined in step 21 whether or not the GPS receiver 8 can receive a GPS signal. If “YES” is determined in step 21, the GPS receiver 8 can receive the GPS signal. Therefore, the process proceeds to step 22 and an error ΔV between the vehicle speed information Vcon by the controller 16 and the vehicle speed information Vgps based on the GPS signal. (ΔV = Vcon−Vgps) is calculated, and it is determined whether or not the error ΔV is smaller than a predetermined threshold value C0 (ΔV <C0).

  If “YES” is determined in step 22, the error ΔV is smaller than the threshold value C 0 and the vehicle speed information Vgps is held in a highly accurate state. Select the output control command value and return.

  On the other hand, when “NO” is determined in step 22, the error ΔV is equal to or greater than the threshold value C 0, and the accuracy of the vehicle speed information Vgps is lowered. Select the control command value to be returned and return.

  If it is determined as “NO” in step 21, the GPS receiver 8 cannot receive a GPS signal. Therefore, the process proceeds to step 24 to select a control command value output from the swell suppression control unit 14 and return. .

  As described above, according to the present embodiment, when the error ΔV between the vehicle speed information Vcon by the controller 16 and the vehicle speed information Vgps based on the GPS signal becomes larger than the predetermined threshold value C0, the wheel speed information by the controller 16 is obtained. The buffer 6 is controlled based on the above. For this reason, even when the GPS receiver 8 can receive a GPS signal, for example, when the reception state of the GPS signal deteriorates and the accuracy of the vehicle speed information Vgps decreases, the buffer 6 based on the wheel speed information by the controller 16. Can be controlled. As a result, it is possible to perform appropriate vibration control without controlling the shock absorber 6 using the vehicle speed information Vgps with reduced accuracy.

  In each of the above-described embodiments, the suspension device 4 is configured to include the shock absorber 6 formed of a damping force adjustment type hydraulic shock absorber called a so-called semi-active damper. However, the present invention is not limited to this, and a configuration using a pressure cylinder capable of adjusting the wheel load by increasing or decreasing the internal pressure by supplying or discharging fluid, such as an active suspension of pneumatic pressure or hydraulic pressure, may be used. Good. Further, the present invention can be applied not only to a suspension device using a fluid but also to a ball screw type or electromagnetic type active suspension.

  In each of the above embodiments, the GPS sensor 9 calculates the vertical velocity information using the Doppler effect of the GPS signal. For example, the vertical velocity information is calculated by differentiating the altitude information with respect to time. May be.

  In each of the above embodiments, the riding comfort control unit 12 based on the skyhook control theory calculates the control command value using the sprung speed V1 from the GPS sensor 9 and the relative speed V2 from the relative speed estimation unit 11. In addition, the present invention is applied to the non-inverted suspension device 4. However, the present invention is not limited to this. For example, when a shock absorber of the damping force reversal type (the magnitude of the change in the damping force on the expansion side and the contraction side is reversed) is used, the data on the relative speed V2 is It is unnecessary.

  Furthermore, in each of the above-described embodiments, the case where the present invention is applied to the controller 10 that controls the shock absorber 6 of the suspension device 4 based on the Skyhook theory has been described as an example. For example, H∞ control or modern control theory is used. It is good also as a structure applied to the controller which performs control which was performed.

  Next, the invention included in each of the embodiments will be described. That is, according to the present invention, a GPS receiver that is provided on a vehicle body and receives a signal from a GPS satellite, and a vehicle body up-and-down direction that calculates an upward and downward movement state of the vehicle body using a signal from the GPS receiver. The motion calculation means and control means for controlling the damping force adjusting shock absorber based on the motion state of the vehicle body vertical motion calculation means are provided. As a result, the vehicle body vertical motion calculation means calculates vertical speed information as the upward and downward movement states of the vehicle body using GPS signals, so that the control means adjusts the damping force by using this vertical speed information. The type shock absorber can be controlled. For this reason, the vertical velocity information is not generated by integration of acceleration as in the prior art, but can be generated directly from the GPS signal, and there is no integration error.

  Further, according to the present invention, there is provided another control means for outputting wheel speed information corresponding to the rotational speed of the wheel, and the control means is configured to output the other information when the GPS receiver cannot receive a signal from a GPS satellite. The damping force adjusting shock absorber is controlled based on wheel speed information from the control means. For this reason, even when the GPS receiver cannot receive the GPS signal and the vertical speed information cannot be obtained, the pitch rate is estimated based on the wheel speed information, for example, and the swell suppression control for suppressing the pitch can be performed. it can.

  According to the present invention, the other control means outputs vehicle speed information corresponding to the speed of the vehicle in addition to the wheel speed information, and the control means receives the signal from the GPS satellite by the GPS receiver. When the error between the vehicle speed information by the other control means and the vehicle speed information calculated based on the signal from the GPS receiver is greater than a predetermined threshold, the other control The damping force adjustment type shock absorber is controlled based on wheel speed information obtained by the means. For this reason, even when the GPS receiver can receive the GPS signal, for example, when the reception state of the GPS signal is deteriorated and the accuracy of the vehicle speed information based on the GPS signal is lowered, it is based on the wheel speed information by other control means. Thus, the damping force adjusting type shock absorber can be controlled. As a result, it is possible to perform appropriate vibration control without controlling the damping force adjusting shock absorber using vehicle speed information based on GPS signals with reduced accuracy.

DESCRIPTION OF SYMBOLS 1 Car body 2 Wheel 4 Suspension device 6 Damping force adjustment type shock absorber 7 Actuator 8 GPS receiver 9 GPS sensor (vehicle body vertical motion calculation means)
10 Controller (control means)
16 Controller (Other control means)

Claims (3)

In a suspension control device including a damping force adjustment type shock absorber that is interposed between a vehicle body and wheels of a vehicle and whose damping force characteristic is variably controlled according to a control command,
A GPS receiver provided on the vehicle body for receiving a signal from a GPS satellite; a vehicle body vertical motion calculating means for calculating an upward and downward movement state of the vehicle body using a signal from the GPS receiver; A suspension control device comprising: control means for controlling the damping force adjusting shock absorber based on the motion state of the vertical motion calculation means. Other control means for outputting wheel speed information according to the rotational speed of the wheel,
2. The control unit according to claim 1, wherein when the GPS receiver cannot receive a signal from a GPS satellite, the control unit controls the damping force adjusting buffer based on wheel speed information from the other control unit. The suspension control device described. The other control means outputs vehicle speed information corresponding to the vehicle speed in addition to the wheel speed information,
The control means is a case where the GPS receiver can receive a signal from a GPS satellite, and there is an error between the vehicle speed information by the other control means and the vehicle speed information calculated based on the signal from the GPS receiver. The suspension control device according to claim 2, wherein the damping force adjusting type shock absorber is configured to be controlled based on wheel speed information by the other control means when it becomes larger than a predetermined threshold value.

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