DEVICE AND METHOD FOR ESTIMATING THE DAMPING FORCE AND DAMPING VELOCITY IN AN ACTIVE SUSPENSION SYSTEM

Abstract

Device for estimating a damper force and a damper velocity for controlling the damper force of a damper in an active suspension system, which device comprises: a first and a second pressure sensor (P1, P2) for detecting pressures of a rebound chamber (111, 511, 711) or a compression chamber (112, 512, 712) of a damper (100, 500, 700) in the active suspension system; a first to third set of valves (VS1, VS2, VS3), wherein the first to third set of valves (VS1, VS2, VS3) is connected between the rebound chamber (111, 511, 711) and an accumulator (400), between the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712) or between the compression chamber (112, 512, 712) and the accumulator (400); and a control device characterized by that the control device is configured to calculate the damper force using the pressures and effective hydraulic pressure areas of the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712) and to calculate the damper velocity using characteristics of pressure fluid rates of the first to third valve sets (VS1, VS2, VS3) and the pressures of the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712), wherein the control device is configured to calculate the damper velocity using the condition that a sum of fluid rates in a node connected between any of the first to third valve sets (VS1, VS2, VS3) and the rebound chamber (111, 511, 711) or the compression chamber (112, 512, 712) is equal to zero.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2016-0090731, filed on July 18, 2016, the disclosure of which is incorporated herein in its entirety. BACKGROUND area

[0002] The present invention relates to an apparatus and method for estimating damper force and damper speed in an active suspension system. More specifically, the present disclosure relates to an apparatus and method for estimating damper force and damper speed in an active suspension system capable of estimating damper force and damper speed at low cost by utilizing characteristics of a damper, a pressure measurement, and hydraulic characteristics of valve sets connected to the damper, without involving a separate external sensor. Description

[0003] In general, a vehicle suspension device is a device that connects an axle and a chassis and suppresses the transmission of vibration or shock to the chassis during vehicle travel to prevent damage to the chassis or cargo and improve ride quality.

[0004] The suspension assembly includes a chassis spring and a damper that dampens free vibrations of the chassis spring. To control the damper's damping force, it is necessary to estimate the damper's velocity.

[0005] A hydraulic system contains various sensors such as a sensor that detects a pressure of a master cylinder, a sensor that detects hydraulic pressure, and a sensor that detects a temperature of main devices such as an engine.

[0006] US 7 386 378 B2 (registered on June 10, 2008 under the title "Linear Control of an Automotive Suspension") discloses a control method of generating an active force by performing a method of controlling a current-controlled piston, a continuously variable semi-active CSVA suspension valve, and a CVSA base suspension valve.

[0007] Generally, in the case of a hydraulic system, pressure-flow rate characteristics vary according to fluid temperature. As a result, even under the same flow conditions, a difference in the force generated by a damper may occur. In addition, since hysteresis is generated according to the compression and rebound of the damper, a difference in the force generated by the damper is generated according to the damper's stroke.

[0008] WO 2007 / 097699 A1 relates to a device in a vehicle damper comprising a damper body filled with a damping medium, in which an element forming a seal against the damper body divides the damper body into two chambers. A microprocessor control unit (SU) is coupled to one or more valve and connection assemblies comprising at least one valve and a plurality of flow channels. Respective valves and flow channels of the valve and connection assembly are coupled both to corresponding damping chambers and to a pressurizing element common to both chambers, so that even in the chamber where a negative pressure prevails, an overpressure always acts.The valve and linkage assemblies comprise a continuously electrically controlled main valve (CES), a check valve (SV), and one or more vent valves (BV), the flow of which can be adjusted separately from the electrically controlled main valve (CES). For small strokes or slow movements, the damping medium flows via the vent valve (BV) through one or more separate leakage flow channels. By arranging the leakage flow channels parallel to the valve and linkage assembly, low-speed damping can be adjusted separately from high-speed damping. The electrically adjustable main valve (CES) can therefore be adjusted to the correct damping characteristic, while the damper is adjusted for small strokes and slow movements.

[0009] Another publication, DE 10 2008 054 573 A1, discloses a method for determining the compression travel of a shock absorber from a signal representing the condition of a vehicle between a wheel and a body. In this method, which provides a cost-effective yet accurate measurement method, a first pressure is measured in the lower oil chamber of the shock absorber. Subsequently, based on this first pressure, the volume of the monotube shock absorber and the temperature of the shock absorber, a volume of the lower oil chamber is calculated, from which a compression travel is determined.

[0010] The control method disclosed in U.S. Patent No. 7,386,378 B2 does not take into account the characteristics of the hydraulic system described above, and thus, it is impossible to overcome a limitation of the hydraulic system itself. That is, a change in damper force according to the supply of valve current cannot be determined without considering a fluid temperature and the hysteresis according to compression and rebound of a damper. A separate external sensor is required to detect the damper force and damper speed.

[0011] KR 10 0 947 288 B1 (registered on March 5, 2010, titled "Sensor module including an acceleration sensor and a relative displacement sensor, damper provided with the same, electronically controlled suspension system including the same, and method for controlling vehicle operation using the same") discloses an example in which the damper force and damper speed are detected using such a separate external sensor. Korean Patent No. 10-0947288 discloses a damper including a sensor module embedded with an acceleration sensor that detects acceleration in a Z-axis direction and a displacement sensor that detects displacement of a piston rod, and coupled to a rod guide.

[0012] As described above, in the past, the damper speed was estimated by sealing an upper end of a cylinder and adding an acceleration sensor and a displacement sensor to a rod guide having a hole into which a piston rod is inserted.

[0013] However, when such a separate external sensor is used as in the past, the damper speed can be estimated, but the installability is low and costs are increased due to the addition of the separate external sensor, resulting in an increase in an operation amount. SUMMARY

[0014] To solve the above problems, an apparatus and method for estimating damper force and damper velocity in an active suspension system according to the present disclosure are provided.

[0015] Various aspects of the present disclosure provide an apparatus and method for estimating damper force and damper velocity in an active suspension system capable of estimating damper force and damper velocity without using a separate external sensor.

[0016] Also provided is an apparatus and method for estimating damper force and damper speed in an active suspension system, which calculates the damper force by using two pressure sensors basically installed in a damper, estimates the damper speed using the calculated damper force and a flow rate of a hydraulic system, and is capable of using the estimated damper speed to control the damper.

[0017] The object of the present disclosure is not limited to the above description, and other objects not explicitly disclosed herein will be clearly understood by those skilled in the art from the following description.

[0018] According to one aspect, an apparatus for estimating damper force and damper speed in an active suspension system may include: first and second pressure sensors for detecting pressures of a rebound chamber and a damper speed chamber, respectively.a compression chamber of a damper in the active suspension system; and a controller for calculating the damper force using the pressures and effective hydraulic pressure areas of the rebound chamber and the compression chamber, and for calculating the damper speed using pressure-fluid rate characteristics of a first to third valve set and the pressures of the rebound chamber and the compression chamber such that a sum of fluid rates in a node connected between any one of the first to third valve sets and the rebound chamber or the compression chamber is zero, wherein the first to third valve sets are connected between the rebound chamber and an accumulator, between the rebound chamber and the compression chamber, or between the compression chamber and the accumulator.

[0019] The control device can calculate the damper force based on a difference between a multiplication of the effective hydraulic pressure area and the pressure of the rebound chamber and a multiplication of the effective hydraulic pressure area and the pressure of the compression chamber.

[0020] The controller may calculate the damper speed with respect to the node connected to the rebound chamber.

[0021] The controller may calculate the damper speed based on a ratio of the effective hydraulic pressure area of ​​the rebound chamber to a flow rate of fluid discharged from the rebound chamber.

[0022] The control device may calculate the discharge flow rate based on a sum of a flow rate with respect to the first valve set connected to the rebound chamber and the accumulator and a flow rate with respect to the second valve set connected between the rebound chamber and the compression chamber, wherein the flow rate with respect to the first valve set is caused by a difference between the detected pressure of the rebound chamber and the detected pressure of the accumulator, and the flow rate with respect to the second valve set is caused by a difference between the detected pressure of the rebound chamber and the detected pressure of the compression chamber.

[0023] The first valve set connected between the compression chamber and the accumulator may include a third check valve and a pump, the second valve set connected between the rebound chamber and the compression chamber may include a first check valve, a first blow-off valve, and a first semi-active valve, and the third valve set connected between the compression chamber and the accumulator may include a second check valve, a second blow-off valve, and a second semi-active valve.

[0024] The control device may calculate the discharge flow rate based on a sum of a flow rate of fluid discharged by the pump and flow rates with respect to the first check valve, the first blow-off valve, and the first semi-active valve, caused by the difference between the detected pressure of the rebound chamber and the detected pressure of the compression chamber.

[0025] The first valve set connected between the compression chamber and the accumulator may include a first check valve and a pump, the second valve set connected between the rebound chamber and the compression chamber may be disposed in a piston of the damper and include a first solenoid valve and a first blowout valve, and the third valve set included between the compression chamber and the accumulator may include a second check valve and a second solenoid valve.

[0026] The control device may calculate the discharge flow rate based on a sum of a flow rate of fluid discharged from the pump, flow rates with respect to the first solenoid valve and the first blow-off valve, and a flow rate with respect to the first check valve, wherein the flow rates with respect to the first solenoid valve and the first blow-off valve are caused by the difference between the detected pressure of the rebound chamber and the detected pressure of the compression chamber, and the flow rate with respect to the first check valve is caused by the detected pressure of the rebound chamber and the detected pressure of the accumulator.

[0027] According to another aspect, a method for estimating damper force and damper velocity in an active suspension system may include: sensing pressures of a rebound chamber and a compression chamber of a damper in the active suspension system; calculating the damper force using the pressures and effective hydraulic pressure areas of the rebound chamber and the compression chamber;and calculating the damper speed using pressure-fluid rate characteristics of a first to third valve and the pressures of the rebound chamber and the compression chamber such that a sum of fluid rates in a node connected between the rebound chamber or the compression chamber and any one of the first to third valve sets is zero, wherein the first to third valve sets are connected between the rebound chamber and an accumulator, between the rebound chamber and the compression chamber, or between the compression chamber and the accumulator;

[0028] When calculating the damper force, the damper force can be calculated using a difference between a multiplication of the effective hydraulic pressure area and the pressure of the rebound chamber and a multiplication of the effective hydraulic pressure area and the pressure of the compression chamber.

[0029] When calculating the damper velocity, the damper velocity can be calculated with respect to a node connected to the rebound chamber.

[0030] When calculating the damper speed, the damper speed can be calculated based on a ratio of the effective hydraulic pressure area of ​​the rebound chamber to a flow rate of fluid discharged from the rebound chamber.

[0031] In calculating the damper speed, the damper speed may be calculated from a sum of a flow rate with respect to the first valve set connected between the rebound chamber and the accumulator and a flow rate with respect to the second valve set connected between the rebound chamber and the compression chamber, wherein the flow rate with respect to the first valve set is caused by a difference between the second pressure of the rebound chamber and the second pressure of the accumulator, and the flow rate with respect to the second valve seat is caused by a difference between the detected pressure of the rebound chamber and the detected pressure of the compression chamber.

[0032] The first valve set connected between the compression chamber and the accumulator may include a third check valve and a pump; the second valve set connected between the rebound chamber and the compression chamber may include a first check valve, a first blowout valve, and a first semi-active valve; and the third valve set connected between the compression chamber and the accumulator may include a second check valve, a second blowout valve, and a second semi-active valve. When calculating the damper speed, the discharge flow rate may be calculated from a sum of a flow rate of fluid discharged by the pump and flow rates with respect to the first check valve, the first blowout valve, and the first semi-active valve caused by the difference between the sensed pressure of the rebound chamber and the sensed pressure of the compression chamber.

[0033] The first valve set connected between the compression chamber and the accumulator may include a first check valve and a pump, the second valve set connected between the rebound chamber and the compression chamber may be arranged on a piston of the damper and may include a first solenoid valve and a first blow-off valve, and the third valve set connected between the compression chamber and the accumulator may include a second check valve and a second solenoid valve.In calculating the damper speed, the discharge flow rate may be calculated from a sum of a flow rate of fluid discharged from the pump, flow rates with respect to the first solenoid valve and the first blowout valve, and a flow rate with respect to the first check valve, wherein the flow rates with respect to the first solenoid valve and the first blowout valve are caused by the difference between the detected pressure of the rebound chamber and the detected pressure of the compression chamber, and the flow rate with respect to the first check valve is caused by the detected pressure of the rebound chamber and the detected pressure of the accumulator.

[0034] According to the present disclosure, in the apparatus and method for estimating damper force and damper speed in an active suspension system, since the damper force is estimated using the detected pressure of the sensor for measuring damper pressure, it is not necessary to install an external sensor, thereby improving installability and reducing costs.

[0035] Furthermore, in the present disclosure, since the damper speed is estimated using characteristics of a hydraulic system and the damper force, it is not necessary to use an external sensor, thereby controlling a damper by reflecting the characteristics of the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The foregoing and other objects, features and advantages of the present disclosure will be better understood from the following detailed description when taken in conjunction with the accompanying drawings in which: Fig. 1 is a diagram illustrating the configuration of an active suspension system including a damper force and damper speed estimating device according to an embodiment; Fig. 2 is a diagram illustrating a method for estimating damper speed to control a damper according to one embodiment; Fig. 3 is a diagram showing an example of a function (fc(Preb, Pcomp)); Fig. 4 is a diagram showing an example of a function (fb(Preb, Pcomp)); Fig. Figure 5 is a diagram showing an example of a function (fs(Preb, Pcomp)); Fig. 6 is a block diagram illustrating the configuration of an active suspension system including a damper force and damper speed estimating device according to another embodiment; and Fig. 7 is a block diagram illustrating the configuration of an active suspension system including a damper force and damper speed estimating device according to still another embodiment. DETAILED DESCRIPTION

[0037] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings, in which components are designated using the same or similar reference numerals regardless of the figure number, and redundant explanations are omitted.

[0038] In the following description of the present disclosure, detailed descriptions of known functions and components incorporated herein are omitted in the event that doing so might impair the clarity of the subject matter of the present disclosure. The accompanying drawings are used to facilitate understanding of the technical idea of ​​the present disclosure, and it should be noted that the idea of ​​the present disclosure is not limited by the accompanying drawings.

[0039] Fig. 1 is a diagram illustrating the configuration of an active suspension system including a damper force and damper speed estimating device according to an embodiment.

[0040] According to Fig. 1, the active suspension system including the device for estimating the damper force and the damper speed according to the embodiment includes a damper 100, a hydraulic system 200 that supplies hydraulic pressure to the damper 100 and enables the calculation of a flow rate, a pump 300 that supplies flow pressure to a fluid of the hydraulic system 200, and an accumulator 400 that dampens pressure pulses.

[0041] The damper 100 includes a cylinder 110 and a piston 120 that moves vertically in the cylinder 110 and divides an interior of the cylinder 110 into a rebound chamber 111 and a compression chamber 112.

[0042] The hydraulic system 200 includes first and second pressure sensors P1 and P2, which detect pressures (Preb and Pcomp) of the rebound chamber 111 and the compression chamber 112, respectively, a first channel 210 connecting the rebound chamber 111 and the pump 300, a second channel 220 connecting the pump 300 and the accumulator 400, a third channel 230 with one end connected to the compression chamber 112, a first check valve CV1, a first blow-off valve BV1 and a first semi-active valve SAV1 arranged in parallel between the first channel 210 and the third channel 230, a second check valve CV2, a second blow-off valve BV2 and a second semi-active valve SAV2 arranged in parallel between the second channel 220 and the third channel 230, and a third check valve CV3 connected to the first channel 210 is connected.

[0043] Next, a configuration and operation of the damper force and damper speed estimating device 100 in the above-configured active suspension system according to the embodiment will be described in detail. A method for estimating the damper force and damper speed to control the damper 100 will be described in detail.

[0044] First, the damper 100 may include the piston 120 that moves vertically in the cylinder 110, and may include a solenoid valve in the piston 120 to control a flow of a fluid.

[0045] The piston 120 includes a piston rod and a piston valve that divides the interior of the cylinder 110 into the rebound chamber 111 and the compression chamber 112. The solenoid valve is arranged in the piston valve.

[0046] The damper 100 with the above-described structure is a configuration of the active suspension system and is used to improve ride quality and control the attitude of a vehicle by reducing vibrations, road roughness, step section, or the like during vehicle travel. The damper 100 should provide a damping force and damping speed suitable for various situations.

[0047] The hydraulic system 200 includes a passage connecting the compression chamber 112 and the rebound chamber 111 of the cylinder 110. For simplicity of description, the case where the passage is divided into the first to third passages 210 to 230 will be described.

[0048] The pump 300 for circulating a fluid is connected to the channel of the hydraulic system 200. The accumulator 400 for dampening pressure pulses is connected to the channel, wherein the pressure pulses are generated when the pump 300 circulates the fluid.

[0049] More specifically, the channel of the hydraulic system 200 includes the first channel 210 connecting the rebound chamber 111 and an outlet of the pump 300, the third channel 230 connecting an inlet of the pump 300 and the accumulator 400, and the second channel 220 connected to the compression chamber 112.

[0050] The first pressure sensor P1 is arranged in the first channel 210 to detect the pressure (Preb) of the rebound chamber 111. The second pressure sensor P2 is arranged in the second channel 220 to detect the pressure (Pcomp) of the compression chamber 112.

[0051] In the above-described configuration, the damper force is calculated using the pressure (Preb) of the rebound chamber 111 detected by the first pressure sensor P1 and the pressure (Pcomp) of the compression chamber 112 detected by the second pressure sensor P2.

[0052] Assuming that an effective hydraulic pressure area of ​​the rebound chamber 111 is Areb and an effective hydraulic pressure area of ​​the compression chamber 112 is Acomp, the damper force (Fdamper) can be represented by Formula 1: Fdamper = Areb × Preb - Acomp × Pcomp

[0053] That is, considering that pressure is the force per unit area, the force during a rebound stroke and the force during a compression stroke can be calculated using the pressure (Preb) and the effective hydraulic pressure area (Areb) of the rebound chamber 111 and the pressure (Pcomp) and the effective hydraulic pressure area (Acomp) of the compression chamber 112, respectively, and the damper force (Fdamper) can be calculated from a difference between the force during the rebound stroke and the force during the compression stroke.

[0054] The damper force (Fdamper) can have a positive (+) or a negative (-) value. The positive (+) and negative (-) values ​​can refer to a value during a rebound stroke or a value during a compression stroke, respectively.

[0055] The damper force (Fdamper) can be calculated by a control device installed in a vehicle (not shown).

[0056] The effective hydraulic pressure area (Areb) of the rebound chamber 111 and the effective hydraulic pressure area (Acomp) of the compression chamber 112 may be a constant known by a design value of the cylinder 110. Accordingly, if the pressures (Preb and Pcomp) of the rebound chamber 111 and the compression chamber 112, respectively detected by the first and second pressure sensors P1 and P2, are known, the control device can easily calculate the damper force (Fdamper).

[0057] Fig. 2 is a diagram illustrating a method of estimating the damper speed to control the damper 100 according to the embodiment.

[0058] According to Fig. 2, flow rates in respective directions with respect to a node A of the first channel 210 may be considered.

[0059] A first flow rate q1 is a flow rate of fluid supplied from node A to the rebound chamber 111. A second flow rate q2 is a flow rate of fluid flowing from node A into the first check valve CV1. A third flow rate q3 is a flow rate of fluid flowing from node A into the first blow-off valve BV1. A fourth flow rate q4 is a flow rate of fluid flowing from node A into the first semi-active valve SAV1. A fifth flow rate q5 is a flow rate of fluid flowing into the third check valve CV3.

[0060] In the node A, the first to fourth flow rates q1 to q4 are determined according to the conditions, and the fifth flow rate q5 denotes a flow rate of fluid flowing substantially toward the node A and having a negative value with respect to a value set in Fig. 2. Therefore, the sum of the first to fifth flow rates q1 to q5 at node A is always zero (0).

[0061] That is, the flow rate in node A can be represented by formula 2: q1+q2+q3+q4+q5=0

[0062] The first flow rate q1 is a multiplication of the damper speed (Vdamper) and the effective hydraulic pressure area (Areb) of the rebound chamber 111. The second flow rate q2 is a flow rate of the first check valve CV1, is caused by characteristics of the first check valve CV1 itself, is represented by a function (fc(Preb, Pcomp)) according to the pressures (Preb and Pcomp) of the rebound chamber 111 and the compression chamber 112, and is a flow rate that can be easily calculated from the pressures (Preb and Pcomp) detected by the first and second pressure sensors P1 and P2 and a specification of the first check valve CV1.

[0063] Fig. 3 is a graph showing an example of a function (fc(Preb, Pcomp)). It can be seen that as a difference between the pressure (Preb) of the rebound chamber 111 and the pressure (Pcomp) of the compression chamber 112 decreases, the second flow rate q2 increases linearly.

[0064] In the same manner as the calculation of the second flow rate q2, the third flow rate q3 and the fourth flow rate q4 can be easily calculated from the functions ((fb(Preb, Pcomp) and fs(Preb, Pcomp)) obtained by the pressures (Preb and Pcomp) of the rebound chamber 111 and the compression chamber 112, and the specifications of the first blow-off valve BV1 and the first semi-active valve SAV1.

[0065] Fig. 4 is a graph showing an example of a function (fb(Preb, Pcomp)). When a difference between the pressure (Preb) of the rebound chamber 111 and the pressure (Pcomp) of the compression chamber 112 is increased to a certain value or more, the third flow rate q3 is linearly increased. When the difference between the pressure (Preb) of the rebound chamber 111 and the pressure (Pcomp) of the compression chamber 112 is lower than the certain value, the third flow rate q3 is zero.

[0066] Fig. 5 is a graph showing an example of a function (fs(Preb, Pcomp)). It can be seen that when a difference between the pressure (Preb) of the rebound chamber 111 and the pressure (Pcomp) of the compression chamber 112 increases, the fifth flow rate q4 is increased non-linearly. In addition, it can be confirmed that when a magnitude of a current supplied to the first semi-active valve SAV1 is increased, the fourth flow rate q4 is increased. However, characteristics of the first semi-active valve SAV1 are not limited to this, and when the magnitude of the current is decreased, the fourth flow rate q4 can be increased.

[0067] Since the fifth flow rate q5 is a flow rate of fluid discharged from the pump 300, the fifth flow rate q5 is defined as a multiplication of a rotational speed (rpm) of a motor for driving the pump 300 by a discharge rate (K) per revolution of the pump 300. When a rotational speed (rpm) of the motor is detected, the fifth flow rate q5 can be confirmed by a specification of the pump 300.

[0068] The following formula 3 can be derived by inserting the above-defined first to fifth flow rates q1 to q5 into the formula 3: (Vdamper×Areb)+fc(Preb, Pcomp)+fb(Preb, Pcomp)+fs(Preb, Pcomp+(RPM×K))=0

[0069] The damper speed (Vdamper) can be represented using formula 4 by formula 3: Vdamper=−((fc(Preb, Pcomp)+fb(Preb, Pcomp)+fs(Preb,Pcomp)+(RPM×K)) / Areb

[0070] In formula 4, all the values ​​on the right side can be easily calculated from specifications of the aforementioned valves by obtaining the pressure (Preb and Pcomp) detected by the first and second pressure sensors P1 and P2, the rotation speed (rpm) of the motor and the current supplied to the first semi-active valve SAV1.

[0071] Therefore, the damper speed (Vdamper) can be easily calculated without installing a separate external sensor.

[0072] The damper speed (Vdamper) can be calculated by a control device installed in a vehicle (not shown).

[0073] The detailed description of the embodiment with reference to the Fig. 1 to 5 described the case where the node A is located in the first channel 210 connected to the rebound chamber 111. That is, the detailed description was given based on the pressure of the rebound chamber 111.

[0074] A case where the node A is arranged in the second passage 220 connected to the compression chamber 112 is based on the pressure of the compression chamber 112, and in the aforementioned functions, Preb and Pcomp can be exchanged for each other.

[0075] A specific example based on the pressure of the compression chamber 112 can be easily implemented by modifying an example described based on the rebound chamber 111. Accordingly, a specific estimation example for the damper speed (Vdamper) based on the compression chamber 112 is omitted.

[0076] The damper force (Fdamper) and the damper speed (Vdamper) calculated above are later used in the operation control of the damper 100 by a control device of a vehicle and are actively involved in improving ride quality and controlling a posture of a vehicle.

[0077] Fig. 6 is a block diagram illustrating the configuration of an active suspension system including a damper force and damper speed estimating device according to another embodiment.

[0078] According to Fig. 6 are a damper 500, a channel connecting the damper 500 and the accumulator 400, and a pump 600 of another embodiment of the active suspension system including the device for estimating the damper force and the damper speed, different from those of the active suspension system shown in Fig. 1 is shown.

[0079] Here, the damper 500 may include a first solenoid valve SV1 and a first blow-off valve BV1 arranged in a piston 520.

[0080] A first check valve CV1 may be connected between a rebound chamber 511 and the accumulator 400. A second check valve CV2 and a second solenoid valve SV2 may be connected in parallel between a compression chamber 512 and the accumulator 400.

[0081] A pump 600 may be a bidirectional pump and may be connected between the rebound chamber 511 and the compression chamber 512.

[0082] In the configuration described above, a controller (not shown) may estimate the damper speed (Vdamper) with respect to a node connected to the rebound chamber 511.

[0083] Here, a first flow rate q1' is a flow rate of fluid supplied to the rebound chamber 511. A second flow rate q2' is a flow rate of fluid flowing into the first check valve CV1. A third flow rate q3' is a flow rate of fluid discharged from the pump 600.

[0084] In a similar manner as with regard to Fig. As described in FIG. 2, the first flow rate q1' may be represented by multiplying the damper speed (Vdamper) by an effective hydraulic pressure area (Areb) of the rebound chamber 511, and may be the sum of a fourth flow rate q4' of fluid flowing into the first solenoid valve SV1 and a fifth flow rate q5' of fluid flowing into the first blowoff valve BV1. Here, the fourth flow rate q4' and the fifth flow rate q5' may be represented by a function (fs'(Peb, Pcomp)) and a function (fb(Preb, Pcomp)) according to the pressures (Preb and Pcomp) of the rebound chamber 511 and the compression chamber 512, respectively.

[0085] Additionally, the second flow rate q2' may be represented by a function (fc(Preb, Pacc)) according to the pressures (Preb and Pacc) of the rebound chamber 511 and the accumulator 44. The third flow rate q3' may be represented by multiplying a rotational speed (rpm) of a motor by an output rate (k) per revolution of the pump 600. The sum of the first to third flow rates is always zero.

[0086] Here, it can be assumed that the pressure (Pacc) of the accumulator 400 is a certain constant value. The functions (fs'(Preb, Pcomp), fb(Preb, Pcomp), and fc(Preb, Pacc)) can be known from the pressure-flow rate characteristics of the first solenoid valve SV1, the first blow-off valve BV1, and the first check valve CV1, respectively.

[0087] Therefore, the damper speed (Vdamper) can be represented by formula 5. Vdamper =−((fc(Preb, Pacc)+fb(Preb, Pcomp)+fs′(Preb,Pcomp)+(RPM×K)) / Areb

[0088] That is, the control device (not shown) may calculate the damper speed (Vdamper) based on a ratio of an effective hydraulic pressure area (Areb) of the rebound chamber 511 to the second to fifth flow rates q2' to q5' of fluids discharged from the rebound chamber 511.Here, the control device (not shown) can calculate the discharge flow rate based on the sum of a flow rate of fluid discharged from the pump 600, the flow rates with respect to the first solenoid valve SV1 and the first blow-off valve BV1, and a flow rate with respect to the first check valve CV1, wherein the flow rates with respect to the first solenoid valve SV1 and the first blow-off valve BV1 are caused by a difference between the pressure (Preb) of the rebound chamber 511 detected by a first pressure sensor P1 and the pressure (Pcom) of the compression chamber 512 detected by a second pressure sensor P2, and the flow rate with respect to the first check valve CV1 is caused by a difference between the pressure (Preb) of the rebound chamber 511 and the pressure (Pacc) of the accumulator 400.

[0089] On the other hand, the controller (not shown) may also estimate the damper force and damper speed using a node connected to the compression chamber 512.

[0090] The estimation of the damper force and the damper speed using the node connected to the compression chamber 512 is based on the pressure (Pcomp) of the compression chamber 512, and in the aforementioned functions, Preb and Pcomp can be interchanged.

[0091] A specific example based on the pressure (Pcomp) of the compression chamber 512 can be easily implemented by modifying an example described based on the rebound chamber 511. Accordingly, a specific estimation example for the damper speed (Vdamper) based on the compression chamber 512 is omitted.

[0092] The damper force (Fdamper) and the damper speed (Vdamper) calculated above are used in the operation control of the damper 500 later by a control device of a vehicle and are actively involved in improving ride quality and controlling a posture of a vehicle.

[0093] Fig. 7 is a block diagram illustrating the configuration of an active suspension system including a damper force and damper speed estimating device according to still another embodiment.

[0094] According to Fig. 7 comprises another embodiment of the active suspension system including the device for estimating the damper force and the damper speed, the active suspension systems according to Fig. 1 and Fig. 6.

[0095] Here a damper 700 can be the same as the damper 100 in Fig. 1. A first valve set VS1 may be connected between a rebound chamber 711 and an accumulator 400. A second valve set VS2 may be connected between the rebound chamber 711 and a compression chamber 712. A third valve set VS3 may be connected between the compression chamber 712 and the accumulator 400.

[0096] The first valve set VS1, the second valve set VS2 and the third valve set VS3 may include at least one of a check valve, a semi-active valve, a blow-off valve and a solenoid valve or a series or parallel combination thereof.

[0097] The damper 700 may be a general system, a semi-active system, or an active system due to the first through third valve sets VS1 through VS3. Specifically, when the damper 700 is the active system, any of the first valve set VS1, the second valve set VS, and the third valve set VS3 may include a pump.

[0098] According to Fig. 1, the first valve set VS1 may include the third check valve CV3 and the pump 300. The second valve set VS2 may include the second valve set CV2, the first blow-off valve SV1, and the first semi-active valve SAV1. The third valve set VS3 may include the second check valve CV2, the second blow-off valve SV2, and the second semi-active valve SAV2.

[0099] According to Fig. 6, the first valve set VS1 may include the first check valve CV1 and the pump 600. The second valve set CV2 may be disposed in the piston 520 and may include the first solenoid valve SV1 and the first purge valve BV1. The third valve set VS3 may include the second check valve CV2 and the second solenoid valve SV2.

[0100] In the above-described configuration, a controller (not shown) may estimate the damper velocity (Vdamper) with respect to a node connected to the rebound chamber 711.

[0101] Here, a first flow rate q1" is a flow rate of fluid supplied to the rebound chamber 711. A second flow rate q2" is a flow rate of fluid flowing into the first valve set SV1. A third flow rate q3" is a flow rate of fluid flowing into the second valve set SV2.

[0102] In a similar manner as with respect to Fig.2, the first flow rate q1" can be represented by multiplying the damper speed (Vdamper) by an effective hydraulic pressure area (Areb) of the rebound chamber 711. The second flow rate q2" and the third flow rate q3" can be represented by pressure-flow rate characteristics with respect to the first valve set VS1 and the second valve set VS2, respectively. The sum of the first to third flow rates q1" to q3" is always zero.

[0103] Here, a flow rate of each of the first to third valve sets VS1 to VS3 can be represented by the sum of the flow rates of fluids flowing into the configuration valves in each of the first to third valve sets VS1 to VS3. The flow rates of fluids flowing into the configuration valves can be represented by Formula 6: Qij = f_ij(Pa,Pb)

[0104] In Formula 6, i is an index of a valve set, j is an index of a configuration valve in a corresponding valve set, and a and b are a pressure index of a chamber or accumulator adjacent to the corresponding valve set.

[0105] Here, the first valve set VS1 requires the pressure (Pacc) of the accumulator 400 measured by the third pressure sensor P3 to accurately calculate each of the configuration valves included in the first valve set VS1. However, in the case of a general damper, since an accumulator is formed at a low pressure and a pressure change in the accumulator is small, the pressure (Pacc) of the accumulator 400 can be assumed to be constant, and f_ij(Pa, Pb) can be known from the pressure-flow rate characteristics of a corresponding configuration valve.

[0106] Therefore, the damper speed (Vdamper) can be represented by formula 7: Vdamper=−(∑jQ1j+∑jQ2j) / ArebVdamper=−(∑jf_1j(Preb, Pacc)+∑jf_2j(Preb, Pcomp)) / Areb

[0107] That is, the control device (not shown) may calculate the damper speed (Vdamper) based on a ratio of the effective hydraulic pressure area (Areb) of the rebound chamber 711 to the second and third flow rates q2" to q3" of fluids discharged from the rebound chamber 711.Here, the control device (not shown) may determine the second and third discharge flow rates q2" to q3" based on the sum of a flow rate with respect to the first valve set VS1 and a flow rate with respect to the second valve set VS2, the flow rate with respect to the first valve set VS1 being caused by a difference between the pressure (Preb) of the rebound chamber 711 and 711 detected by the first pressure sensor P1 and the pressure (Pacc) of the accumulator 400 detected by the third pressure sensor P3 or represented by a constant, and the flow rate with respect to the second valve set VS2 being caused by a difference between the pressure (Preb) and the pressure (Pcom) of the compression chamber 712 detected by the second pressure sensor P2.

[0108] On the other hand, the controller (not shown) may also estimate the damper force and damper speed using a node connected to the compression chamber 712.

[0109] The estimation of the damper force and the damper velocity using the node connected to the compression chamber 712 is based on the pressure Pcomp of the compression chamber 712, and in the aforementioned functions, a function f_ij(Preb, Pacc) can be exchanged with a function f_3j(Pacc, Pcomp).

[0110] A specific example based on the pressure (Pcomp) of the compression chamber 712 can be easily implemented by modifying an example described based on the rebound chamber 711.

[0111] Accordingly, a specific estimation example for the damper speed (Vdamper) based on the compression chamber is omitted.

[0112] The damper force (Fdamper) and the damper speed (Vdamper) calculated above are later used in the operation control of the damper 700 by a control device of a vehicle and are actively involved in improving ride quality and controlling a posture of a vehicle.

[0113] Embodiments described in this specification and the accompanying drawings are merely examples that describe a portion of the scope and spirit of the present disclosure. Therefore, the embodiments disclosed herein are intended to describe the scope and spirit of the present disclosure, and not for purposes of limitation. Therefore, it is obvious that the present disclosure is not limited to these embodiments. It should be understood that modifications and detailed embodiments that are readily apparent to those skilled in the art as being within the scope and spirit contained in the description and drawings of the present disclosure fall within the scope of the present disclosure.

Claims

[1] A device for estimating a damper force and a damper speed for controlling the damper force of a damper in an active suspension system, which device comprises: a first and a second pressure sensor (P1, P2) for detecting pressures of a rebound chamber (111, 511, 711) and a compression chamber (112, 512, 712) of a damper (100, 500, 700) in the active suspension system; a first to third valve set (VS1, VS2, VS3), wherein the first to third valve set (VS1, VS2, VS3) is connected between the rebound chamber (111, 511, 711) and an accumulator (400), between the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712) or between the compression chamber (112, 512, 712) and the accumulator (400); and a control device, characterized by , that the control device is designed to calculate the damper force using the pressures and effective hydraulic pressure areas of the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712) and to calculate the damper speed using characteristics of pressure fluid rates of the first to third valve sets (VS1, VS2, VS3) and the pressures of the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712), wherein the control device is designed to calculate the damper speed using the condition that a sum of fluid rates in a node connected between any of the first to third valve sets (VS1, VS2, VS3) and the rebound chamber (111, 511, 711) or the compression chamber (112, 512, 712) is equal to zero is. [2] Device according to claim 1, wherein the control device is designed to calculate the damper force based on a difference between a multiplication of the effective hydraulic pressure area by the pressure of the rebound chamber (111, 511, 711) and a multiplication of the effective hydraulic pressure area by the pressure of the compression chamber (112, 512, 712). [3] Apparatus according to claim 1 or 2, wherein the control device is arranged to calculate the damper speed with respect to the node connected to the rebound chamber (111, 511, 711). [4] Device according to one of claims 1 to 3, wherein the control device is designed to calculate the damper speed based on a ratio of the effective hydraulic pressure area of ​​the rebound chamber (111, 511, 711) to a flow rate of a fluid discharged from the rebound chamber (111, 511, 711). [5] The device according to any one of claims 1 to 4, wherein the control device is configured to calculate the discharge flow rate based on a sum of a flow rate with respect to the first valve set (VS1) connected between the rebound chamber (111, 511, 711) and the accumulator (400) and a flow rate with respect to the second valve set (VS2) connected between the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712), wherein the flow rate with respect to the first valve set (VS1) is determined by a difference between the detected pressure of the rebound chamber (111, 511, 711) and the detected pressure of the accumulator (400), and the flow rate with respect to the second valve set (VS2) is determined by a difference between the detected pressure of the rebound chamber (111, 511, 711) and the detected pressure of the compression chamber (112, 512, 712). [6] Device according to one of claims 1 to 5, wherein the first valve set (VS1) connected between the compression chamber (112, 712) and the accumulator (400) comprises a third check valve (CV3) and a pump (300), the second valve set (VS2), which is connected between the rebound chamber (111, 711) and the compression chamber (112, 712), comprises a first check valve (CV1), a first blow-off valve (BV1) and a first semi-active valve (SAV1), and the third valve set (VS3), which is connected between the compression chamber (112, 712) and the accumulator (400), comprises a second check valve (CV2), a second blow-off valve (BV2) and a second semi-active valve (SAV2). [7] The apparatus according to claim 6, wherein the control device is configured to calculate the discharge flow rate based on a sum of a flow rate of a fluid discharged from the pump (300) and flow rates with respect to the first check valve (CV1), the first blow-off valve (BV1) and the first semi-active valve (SAV1), caused by the difference between the detected pressure of the rebound chamber (111) and the detected pressure of the compression chamber (112). [8] Device according to one of claims 1 to 7, wherein the first valve set (VS1) connected between the compression chamber (512, 712) and the accumulator (400) comprises a first check valve and a pump (600), the second valve set (VS2) connected between the rebound chamber (511, 711) and the compression chamber (512, 712) is arranged in a piston (520) of the damper (500, 700) and comprises a first solenoid valve (SV1) and a first blow-off valve (BV1), and the third valve set (VS3) connected between the compression chamber (512, 712) and the accumulator (400) comprises a second check valve (CV2) and a second solenoid valve (SV2). [9] The device according to claim 8, wherein the control device is configured to calculate the discharge flow rate based on a sum of a flow rate of a fluid discharged from the pump (600), flow rates with respect to the first solenoid valve (SV1) and the first blow-off valve (BV1), and a flow rate with respect to the first check valve (CV1), wherein the flow rates with respect to the first solenoid valve (SV1) and the first blow-off valve (BV1) are caused by the difference between the detected pressure of the rebound chamber (511) and the detected pressure of the compression chamber (512), and the flow rate is caused with respect to the rebound chamber (511) and the detected pressure of the accumulator (400). [10] A method for estimating a damper force and a damper speed for controlling the damper force of a damper in an active suspension system, comprising: Detecting pressures of a rebound chamber (111, 511, 711) and a compression chamber (112, 512, 712) of a damper (100, 500, 700) in the active suspension system; Calculating the damper force using the pressures and effective hydraulic pressure areas of the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712); and Calculating the damper speed using characteristics of pressure fluid rates of a first to third valve and the pressures of the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712) such that a sum of fluid rates in a node located between the rebound chamber (111, 511, 711) or the compression chamber (112, 512, 712) and any of the first to third valve sets (VS1, VS2, VS3) is equal to zero, wherein the first to third valve sets (VS1, VS2, VS3) are connected between the rebound chamber (111, 511, 711) and an accumulator (400), between the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712) or between the compression chamber (112, 512, 712) and the accumulator (400). [11] Method according to claim 10, wherein, in calculating the damper force, the damper force is calculated based on a difference between a multiplication of the effective hydraulic pressure area by the pressure of the rebound chamber (111, 511, 711) and a multiplication of the effective hydraulic pressure area by the pressure of the compression chamber (112, 512, 712). [12] A method according to claim 10 or 11, wherein the calculation of the damper speed comprises calculating the damper speed with respect to a node connected to the rebound chamber (111, 511, 711). [13] A method according to any one of claims 11 to 12, wherein, in calculating the damper speed, the damper speed is calculated based on a ratio of the effective hydraulic pressure area of ​​the rebound chamber (111, 511, 711) to a flow rate of a fluid discharged from the rebound chamber (111, 511, 711). [14] A method according to any one of claims 11 to 13, wherein, in calculating the damper speed, the damper speed is calculated from a sum of a flow rate with respect to the first valve set (VS1) connected between the rebound chamber (111, 511, 711) and the accumulator (400) and a flow rate with respect to the second valve set (VS2) connected between the rebound chamber (111, 511, 711) and the compression chamber (112, 512, 712), wherein the flow rate with respect to the first valve set (VS1) is caused by a difference between the detected pressure of the rebound chamber (111, 511, 711) and the detected pressure of the accumulator (400), and the flow rate with respect to the second valve set (VS2) is caused by a difference between the detected pressure of the rebound chamber (111, 511, 711) and the detected pressure of the compression chamber (112, 512, 712). [15] Method according to one of claims 11 to 13, wherein the first valve set (VS1) connected between the compression chamber (112, 712) and the accumulator (400) comprises a third check valve (CV3) and a pump (300), the second valve set (VS2), which is connected between the rebound chamber (111, 711) and the compression chamber (112, 712), comprises a first check valve (CV1), a first blow-off valve (BV1) and a first semi-active valve (SAV1), the third valve set (VS3), which is connected between the compression chamber (112, 712) and the accumulator (400), comprises a second check valve (CV2), a second blow-off valve (BV2) and a second semi-active valve (SAV2), and in calculating the damper speed, the discharge flow rate is calculated from a sum of a flow rate of a fluid discharged from the pump (300) and flow rates with respect to the first check valve (CV1), the first blow-off valve (BV1) and the first semi-active valve (SAV1) caused by the difference between the detected pressure of the rebound chamber (111) and the detected pressure of the compression chamber (112). [16] Method according to one of claims 11 to 13, wherein the first valve set (VS1) connected between the compression chamber (512, 712) and the accumulator (400) comprises a first check valve (CV1) and a pump (600), the second valve set (VS2), which is connected between the rebound chamber (511, 711) and the compression chamber (512, 712), is arranged on a piston (520, 720) of the damper (500, 700) and has a first solenoid valve (SV1) and a first blow-out valve (BV1), the third valve set (VS3) connected between the compression chamber (512, 712) and the accumulator (400) comprises a second check valve (CV2) and a second solenoid valve (SV2), and in calculating the damper speed, the output flow rate is calculated from a sum of a flow rate of a fluid output from the pump (600), flow rates with respect to the first solenoid valve (SV1) and the first blow-off valve (BV1), and a flow rate with respect to the first check valve (CV1), wherein the flow rates with respect to the first solenoid valve (SV1) and the first blow-off valve (BV1) are caused by the difference between the detected pressure of the rebound chamber (511) and the detected pressure of the compression chamber (512), and the flow rate with respect to the first check valve (CV1) is caused by the detected pressure of the rebound chamber (511) and the detected pressure of the accumulator (400).

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