JP2016137737A - Control device for damping force variable damper and damping force variable damper system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for damping force variable damper and the like in which a solenoid valve is used to vary a cross sectional area of a channel, and which hardly have a continued large current flowing through the solenoid valve and which hardly cause a coil to be short-circuited.SOLUTION: A control device for damping force variable damper comprises: a target current determination part 161 for determining a target current ITA to be supplied to a solenoid valve which controls a damping force of the damping force variable damper; an upper limit setting part 163 for setting an upper limit value of a current to be supplied to the solenoid valve; a supply current determination part 166 for determining the supply current supplied to the solenoid valve based on the target current ITA and the upper limit value. The upper limit setting part 163 determines a coefficient for increasing/decreasing the upper limit value according to the supply current which has been already determined, and further determines the upper limit value based on the coefficient.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a control device for a damping force variable damper and a damping force variable damper system.

BACKGROUND ART Suspension devices for vehicles such as automobiles are equipped with a damper for appropriately mitigating vibrations transmitted from the road surface to the vehicle body during traveling and improving riding comfort and driving stability. The damper is provided, for example, in a cylinder so as to be movable so as to partition the cylinder, a rod member connected to the partition member, and compensates for the volume of the rod member oil as the rod member moves. A liquid reservoir chamber is provided, and a damping force is generated by applying resistance to the flow of liquid generated as the partition member moves.
At this time, if the cross-sectional area of the flow path through which the liquid flows is changed, the resistance of the liquid flow changes, so that the damping force can be changed. For this reason, recently, a damping force variable damper has been proposed that utilizes this phenomenon to make the damping force variable.

  For example, in Patent Document 1, the target current generation unit searches / sets the first upper limit current value corresponding to the power generation amount of the alternator, and then the target current generation unit sets the second upper limit current value corresponding to the coil temperature. Search / set. Next, the target current generation unit selects the smaller one of the first upper limit current value and the second upper limit current value as the upper limit current value. When the basic target current exceeds the upper limit current value, the target current generating unit sets the upper limit current value as the target current, and outputs a drive current corresponding to the target current to the MLV coil of each damper. Is described.

JP 2009-23377 A

In order to change the cross-sectional area of the flow path, for example, a valve body or the like is provided in the flow path, and this valve body can be moved using an electromagnetic valve. And the movement amount of a valve body can be performed by controlling the electric current supplied to a solenoid valve.
However, when a state where a large current is passed through the solenoid valve continues, excessive heat is generated in the coil, which is a member constituting the solenoid valve, and the coil is easily short-circuited. In addition, the durability of the coil tends to be low.
The present invention provides a damping force variable damper control device, etc., in which when a solenoid valve is used to change the cross-sectional area of a flow path, a state where a large current is passed through the solenoid valve does not continue and a coil is not easily short-circuited. The purpose is to do.

  For this purpose, the present invention provides a control device for a damping force variable damper, a target current determining unit that determines a target current to be supplied to an electromagnetic valve that controls the damping force of the damping force variable damper, An upper limit setting unit that sets an upper limit value of the current supplied to the valve, and a supply current determination unit that determines a supply current to be supplied to the solenoid valve from the target current and the upper limit value, and the upper limit setting unit has already been determined The damping force variable damper control device determines a coefficient for increasing or decreasing the upper limit value based on a supply current, and determines the upper limit value from the coefficient.

Here, the upper limit setting unit may determine the coefficient from the moving average of the supply current already determined within a predetermined time.
The upper limit setting unit increases the upper limit value when the already determined moving average of the supply current is smaller than the first threshold value, and is larger than the second threshold value set as a value equal to or higher than the first threshold value. May reduce the upper limit.
Furthermore, the upper limit setting unit may maintain the upper limit when the already determined moving average of the supply current is equal to or higher than the first threshold and equal to or lower than the second threshold.
Furthermore, the upper limit setting unit may determine the coefficient from the integrated value of the supply current that has already been determined within a predetermined time.
Furthermore, the upper limit setting unit increases the upper limit value when the already determined integrated value of the supply current is smaller than the first threshold value, and exceeds the second threshold value set as a value equal to or higher than the first threshold value. May reduce the upper limit.
Furthermore, the upper limit setting unit may maintain the upper limit value when the already determined integrated value of the supply current is not less than the first threshold value and not more than the second threshold value.
Furthermore, there may be a plurality of damping force variable dampers, a plurality of solenoid valves, and the supply current determination unit may select the minimum one from the supply currents determined for each of the plurality of solenoid valves.

  For this purpose, when viewed from another point of view, the present invention includes a damping force variable damper having an electromagnetic valve for adjusting damping force, and a control device for controlling the electromagnetic valve. A target current determining unit that determines a target current to be supplied to the valve, an upper limit setting unit that sets an upper limit value of the current to be supplied to the solenoid valve, and a supply current to be supplied to the solenoid valve from the target current and the upper limit value The upper limit setting unit is a damping force variable damper system that determines a coefficient for increasing / decreasing the upper limit value based on the already determined supply current, and determines the upper limit value from the coefficient.

  ADVANTAGE OF THE INVENTION According to this invention, when a solenoid valve is used in order to change the cross-sectional area of a flow path, the damping force variable damper etc. which are hard to short-circuit the coil used for a solenoid valve can be provided.

1 is a diagram illustrating a schematic configuration of a vehicle to which a damping force variable damper according to an embodiment is applied. It is a figure which shows schematic structure of the suspension apparatus of this embodiment. It is a figure for demonstrating in detail the solenoid valve periphery of this embodiment. It is a block diagram of a control device concerning this embodiment. It is a block diagram of the supply current calculation part of this embodiment. It is the figure which showed the relationship between the moving average of an actual electric current, and a coefficient. It is the flowchart explaining operation | movement of the supply current calculation part.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
<Description of the entire vehicle>
FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 100 to which a damping force variable damper according to the present embodiment is applied.
The illustrated vehicle 100 includes four wheels, a right front wheel 110FR, a left front wheel 110FL, a right rear wheel 110RR, and a left rear wheel 110RL. The right front wheel 110FR, the left front wheel 110FL, the right rear wheel 110RR, and the left rear wheel 110RL include a right front suspension device 120FR, a left front suspension device 120FL, and a right rear suspension device, which are examples of damping force variable dampers, respectively. 120RR and a left rear suspension 120RL are provided. When the right front wheel 110FR, the left front wheel 110FL, the right rear wheel 110RR, and the left rear wheel 110RL are not distinguished, they may be collectively referred to as “wheels 110” hereinafter. When the right front suspension device 120FR, the left front suspension device 120FL, the right rear suspension device 120RR, and the left rear suspension device 120RL are not distinguished, they may be collectively referred to as “suspension device 120” hereinafter.

  The vehicle 100 also includes a control device 150 that controls the damping force of the suspension device 120. The control device 150 is realized by an ECU (Electronic Control Unit) or the like.

FIG. 2 is a diagram illustrating a schematic configuration of the suspension device 120 according to the present embodiment.
[Configuration / Function of Suspension Device 120]
As shown in FIG. 2, the suspension device 120 includes a hydraulic shock absorber 1 and a coil spring 2 disposed outside the hydraulic shock absorber 1. The coil spring 2 is held by a spring seat 3 and a spring seat 4 provided at both ends. The suspension device 120 includes a bolt 5 for attachment to a vehicle body and the like, and a wheel side attachment portion 6 provided at a lower portion of the hydraulic shock absorber 1.

[Configuration and function of hydraulic shock absorber 1]
As shown in FIG. 2, the hydraulic shock absorber 1 includes a cylinder portion 10, a piston rod 20, a piston 30, a bottom valve 40, and a solenoid valve (electromagnetic valve) 50.

(Configuration and function of cylinder part 10)
The cylinder part 10 includes a cylinder 11, an outer cylinder 12 provided outside the cylinder 11, and a damper case 13 provided further outside the outer cylinder 12. The cylinder 11, the outer cylinder 12 and the damper case 13 are arranged concentrically (coaxially).
In the following description, the central axis direction of the cylinder of the damper case 13 is simply referred to as “axial direction”. Further, the lower end side in the drawing in the axial direction of the damper case 13 is referred to as “one”, and the upper end side in the drawing in the axial direction of the damper case 13 is referred to as “the other”.

The cylinder 11 (first cylinder) is provided such that the piston 30 is slidable in the axial direction on the inner peripheral surface, and the outer periphery of the piston 30 moves while contacting the inner periphery of the cylinder 11.
Further, the cylinder 11 has a cylinder opening 11 </ b> H that is a path through which oil flows between the cylinder 11 and the connecting path L, which will be described later, on the other end side and on one side of the rod guide 15.

  The outer cylinder 12 is provided outside the cylinder 11 and inside the damper case 13. The outer cylindrical body 12 forms a communication path L serving as an oil path between the inside of the cylinder 11 and a reservoir chamber R described later, between the outer cylinder 12 and the cylinder 11. Further, the outer cylinder 12 has an outer cylinder opening 12 </ b> H at a position facing the solenoid valve 50.

  The damper case 13 (second cylinder) accommodates the cylinder 11 and the outer cylindrical body 12 on the inner side in the axial direction and the circumferential direction. The damper case 13 absorbs oil in the cylinder 11 and supplies oil into the cylinder 11 between the outer cylinder 12 and compensates for the volume of oil corresponding to the forward and backward movement of the piston rod 20. A reservoir chamber R is formed.

  The damper case 13 has a case opening 13H at a position where the solenoid valve 50 (throttle mechanism) is attached. A solenoid cylinder 50S described later is attached to the outer periphery of the damper case 13 and outside the case opening 13H. A suction port 52 and a joint member 12G, which will be described later, are passed through the case opening 13H.

(Configuration and function of piston 30)
The piston 30 includes a piston body 31 and a valve 32 provided on the other end side in the axial direction of the piston body 31.
The piston 30 is provided so as to be movable in the axial direction in the cylinder 11 and divides the space in the cylinder 11 into a first oil chamber Y1 and a second oil chamber Y2 that store liquid.

  The piston body 31 has an oil passage 31H formed in the axial direction. A plurality of oil passages 31 </ b> H (four in the present embodiment) are formed at equal intervals in the circumferential direction, and constitute a passage through which oil flows via the piston body 31.

  The valve 32 is provided at the other end of the piston body 31 and attached to the other side of the plurality of oil passages 31H.

(Configuration and function of bottom valve 40)
As shown in FIG. 2, the bottom valve 40 includes a valve body 41 having a plurality of oil passages 46 formed in the axial direction, and a part of the oil passages 46 formed in the valve body 41. The valve | bulb 42 which plugs up the other edge part of the axial direction in and the volt | bolt 40B which fixes these members is provided.

  The valve body 41 separates the first oil chamber Y1 and the reservoir chamber R.

(Configuration and function of solenoid valve 50)
FIG. 3 is a diagram for explaining in detail the periphery of the solenoid valve of the present embodiment.
The solenoid valve 50 is provided on the side portion of the damper case 13. The solenoid valve 50 includes a solenoid cylinder 50S, a solenoid mechanism 51, a suction port 52, a valve stopper 53, a valve body 54, and a spring 55.

  The solenoid cylinder 50 </ b> S is a cylindrical member and is provided so that one axial opening faces the case opening 13 </ b> H of the damper case 13. In the present embodiment, the solenoid cylinder 50S is provided on the side of the damper case 13 so as to face the direction intersecting the axial direction.

The solenoid mechanism 51 includes a coil 511, a housing 511H, a plunger 512, a magnetic body 513, and a fixed core 514.
The coil 511 is provided along the axial direction of the plunger 512 and is held by the housing 511H. A coil (511) is connected to a conducting wire (not shown), and generates a magnetic field when energized through the conducting wire. Note that control of energization of the coil 511 is performed by the control device 150 (see FIG. 1). Further, the suspension device 120 is actually composed of four parts, that is, the right front suspension device 120FR, the left front suspension device 120FL, the right rear suspension device 120RR, and the left rear suspension device 120RL as described in FIG. For this reason, the solenoid valve 50 also includes the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL. As will be described in detail later, the control device 150 performs current control by energizing these coils 511 separately.

  The plunger 512 is supported by the housing 511H so as to be movable in the axial direction via a bearing. A magnetic body 513 such as a magnet is fixedly attached to the plunger 512. And the plunger 512 contacts the valve body 54 by the one end part side.

  The fixed core 514 is disposed closer to the valve body 54 than the magnetic body 513 in the axial direction of the plunger 512. The fixed core 514 is configured to receive and excite a magnetic field generated when the coil 511 is energized.

  In the present embodiment, an oil throttle portion V in the solenoid valve 50 is formed by the annular flow path 53r of the valve stopper 53 and the distal end portion 54p of the valve body 54. That is, in the solenoid valve 50 of the present embodiment, the damping force is generated by narrowing the oil flow passage section at the throttle portion V. Further, the damping force is adjusted by changing the cross-sectional area of the oil flow by changing the distance of the valve body 54 with respect to the valve stopper 53 by the plunger 512 of the solenoid mechanism 51.

  That is, when the distance of the valve body 54 with respect to the valve stopper 53 is larger, the flow path cross-sectional area becomes larger. In this case, the damping force can be further reduced. Moreover, when the distance of the valve body 54 with respect to the valve stopper 53 is smaller, the flow path cross-sectional area becomes smaller. In this case, the damping force can be further increased.

[Operation of hydraulic shock absorber 1]
The operation of the hydraulic shock absorber 1 configured as described above will be described.
First, the operation of the hydraulic shock absorber 1 during the compression stroke will be described.
At the time of the compression stroke, as shown in FIG. 2, when the piston 30 moves to one end side in the axial direction (downward in FIG. 2), the oil in the first oil chamber Y1 is moved by the movement of the piston 30. The pressure in the first oil chamber Y1 is increased by being pushed.
In the bottom valve 40, the valve 42 is provided on the other side of the valve body 41, and the pressure on the reservoir chamber R side is relatively low compared to the first oil chamber Y1, so the valve 42 closes the oil passage 46. Will remain.

In the piston 30, the pressure in the first oil chamber Y1 is relatively higher than that in the second oil chamber Y2. At this time, the valve 32 that closes the oil passage 31H is opened by the pressure acting on the oil passage 31H. Then, the oil flows from the first oil chamber Y1 to the second oil chamber Y2.
Further, oil corresponding to the volume of the piston rod 20 flows out from the cylinder opening 11H, flows through the communication path L, and is supplied to the solenoid valve 50.

  The solenoid valve 50 receives oil supply through a suction port 52 connected to the communication path L. The oil flowing through the suction port 52 is throttled at a throttle portion V formed between the valve body 54 and the valve stopper 53. At this time, the damping force during the compression stroke in the solenoid valve 50 is obtained.

  Then, the oil that has passed through the throttle portion V flows out into the reservoir chamber R.

Next, the operation of the hydraulic shock absorber 1 during the expansion stroke will be described.
As shown in FIG. 2, when the piston 30 moves to the other end side in the axial direction (upward in FIG. 2), the first oil chamber Y1 becomes negative pressure. As a result, the oil in the reservoir chamber R passes through the oil passage 46 of the bottom valve 40, opens the valve 42 that closes the oil passage 46, and flows into the first oil chamber Y1.

  Then, the pressure in the second oil chamber Y2 increased by the movement of the piston 30 toward the other end in the axial direction flows out from the cylinder opening 11H, flows through the communication path L, and is supplied to the solenoid valve 50. The subsequent oil flow in the solenoid valve 50 is as described above, and the damping force of the solenoid valve 50 during the extension stroke is obtained.

[Description of Control Device 150]
Next, the control device 150 will be described in detail.
FIG. 4 is a block diagram of the control device 150 according to the present embodiment.
The control device 150 includes a supply current calculation unit 160 that calculates a supply current ITF to be supplied to the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL, and a supply current calculation unit. And a control unit 180 that performs feedback control and the like based on the supply current ITF calculated by 160.

  Based on the state quantity representing the behavior of the vehicle 100, the supply current calculation unit 160 targets the current supplied to the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL. The target current ITA is calculated. Examples of the state quantity representing the behavior of the vehicle 100 include unsprung speed, unsprung acceleration, sprung speed, sprung acceleration, stroke speed of the hydraulic shock absorber, stroke acceleration of the hydraulic shock absorber, or stroke amount of the hydraulic shock absorber. Can be used. The state quantity representing the behavior of the vehicle may be calculated based on the fluctuation of the wheel speed, or may be detected using an acceleration sensor or a stroke sensor.

  The control unit 180 includes an operation control unit 181 that controls the operations of the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL, the right front solenoid valve 50FR, and the left front Side solenoid valve 50FL, right rear side solenoid valve 50RR, left rear side solenoid valve 50RL, an electromagnetic valve drive unit 182, right front side solenoid valve 50FR, left front side solenoid valve 50FL, right rear side solenoid valve 50RR, left rear side Each of the side solenoid valves 50RL includes a detection unit 183 that detects an actual current IM and an actual voltage VM that actually flow.

  The operation control unit 181 includes a feedback (F / B) control unit 181a that performs feedback control based on a deviation between the supply current ITF calculated by the supply current calculation unit 160 and the actual current IM detected by the detection unit 183. A PWM control unit 181b that performs PWM control on each of the side solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL.

  The feedback control unit 181a obtains a deviation between the supply current ITF and the actual current IM detected by the detection unit 183, and performs feedback processing so that the deviation becomes zero. The feedback control unit 181a performs, for example, a proportional process with a proportional element with respect to a deviation between the supply current ITF and the actual current IM, an integral process with an integral element, and an addition operation unit adds these values. Can be illustrated. Alternatively, for example, the feedback control unit 181a performs a proportional process with a proportional element on the deviation between the supply current ITF and the actual current IM, an integral process with an integral element, a differential process with a differential element, and an adder calculation unit with these It is possible to exemplify that the values are added.

  The PWM control unit 181b changes the duty ratio and opens the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL (the right front solenoid valve 50FR and the left front solenoid valve). 50FL, the voltage applied to the coil 511 of the right rear solenoid valve 50RR and the left rear solenoid valve 50RL) is PWM-controlled. When PWM control is performed, the voltage applied to the coil 511 of the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL is applied in a pulse shape corresponding to the duty ratio. The current flowing through the coil 511 of the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL increases or decreases in proportion to the duty ratio. For example, the PWM control unit 181b sets the duty ratio to zero when the supply current ITF is zero, and sets the duty ratio to 100% when the supply current ITF is the maximum current described above. Can be illustrated.

  The solenoid valve drive unit 182 is connected, for example, between the positive line of the power source and the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the coil 511 of the left rear solenoid valve 50RL. A transistor is provided. Then, the driving of the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL is controlled by driving the gate of the transistor and switching the transistor. To do.

  The detection unit 183 applies a voltage generated at both ends of the shunt resistor connected to the solenoid valve driving unit 182 to each of the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL. The value of the flowing actual current IM is detected. Further, the voltages applied to the relays (not shown) for switching ON / OFF of the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL are respectively applied by measuring. The value of the actual voltage VM is detected.

[Description of Supply Current Calculation Unit 160]
Next, the supply current calculation unit 160 will be described in detail.
FIG. 5 is a block diagram of the supply current calculation unit 160 of the present embodiment.
As shown in the figure, the supply current calculation unit 160 of this embodiment includes a target current determination unit 161, a map storage unit 162, an upper limit setting unit 163, a time measurement unit 164, and a supply current determination unit 166.

  The target current determination unit 161 determines a target current ITA to be supplied to the solenoid valve 50 by, for example, skyhook theory. In the skyhook theory, the target current ITA is determined based on the vertical speed on the spring of the suspension device 120 and the stroke amount of the suspension device 120.

  For example, the target current determination unit 161 creates a map indicating the correspondence between the vertical speed on the spring, the stroke amount Sc, and the target current ITA, which is created based on an empirical rule in advance, and the vertical speed and stroke amount on the spring. The target current ITA is determined by substituting Sc. This map is stored in the map storage unit 162.

  In the above-described example, the target current determining unit 161 uses the Skyhook theory to determine the target current ITA based on the vertical speed on the spring and the stroke amount Sc. However, the present invention is not limited to this. For example, the vehicle speed at the time of acceleration / deceleration of the vehicle 100 may be detected, and the target current ITA may be determined based on this. In addition, the target current ITA may be determined based on the steering operation angle, and the skyhook theory, the vehicle speed, and the steering operation angle may be used in combination. Further, a switch may be provided for the user to set the damping force of the hydraulic shock absorber 1, and the user may determine the damping force of the hydraulic shock absorber 1 by switching this switch.

  Here, when the state where the target current ITA is large continues for a long time, the state where the actual current IM supplied to the solenoid valve 50 is also large continues for a long time. As a result, excessive heat generation occurs in the coil 511 (see FIG. 3), and the coil 511 may be short-circuited.

  Therefore, in the present embodiment, the supply current calculation unit 160 is provided with a map storage unit 162, an upper limit setting unit 163, a time measurement unit 164, and a supply current determination unit 166, and performs correction to limit the target current ITA. We are trying to control the problem.

  The upper limit setting unit 163 sets an upper limit value of the current supplied to the solenoid valve 50. The upper limit setting unit 163 determines the upper limit value based on the already determined supply current. The already determined supply current includes the actual current IM that actually flows in the solenoid valve 50 based on the supply current ITF determined in the past, in addition to the value of the supply current ITF determined in the past by the supply current determination unit 166. Can be used. Hereinafter, a case where the actual current IM is used as the already determined supply current will be described.

  Specifically, the upper limit setting unit 163 acquires the actual current IM from the detection unit 183 at a predetermined time interval. This time interval can be set, for example, every 100 ms (milliseconds). The timing for acquiring the actual current IM is determined by the time measured by the time measuring unit 164. And the upper limit setting part 163 calculates | requires the moving average of the acquired actual current IM. The moving average is obtained from the actual current IM acquired within a predetermined time. For example, the moving average can be an average value of 50 times of the acquired actual current IM. In this case, the time required to calculate the moving average is 100 ms × 50 = 5 s (seconds).

  Further, the upper limit setting unit 163 obtains a coefficient for increasing or decreasing the upper limit value from the calculated moving average of the actual current IM. The relationship between the moving average of the actual current IM and the coefficient is stored in the map storage unit 162 as a map, for example. The upper limit setting unit 163 can obtain a coefficient for increasing or decreasing the upper limit value from the moving average of the actual current IM by referring to this map.

FIG. 6 is a diagram showing the relationship between the moving average of the actual current IM and the coefficient. In FIG. 6, the horizontal axis represents the moving average of the actual current IM, and the vertical axis represents the coefficient.
In FIG. 6, the first threshold value X1 and the second threshold value X2 which are two threshold values are provided in the moving average of the actual current IM. In the present embodiment, a current value of 0.4 A is set as the first threshold value X1, and 1.0 A is set as the second threshold value X2. A region where the moving average of the actual current IM is 0A to X1 is a return region, a region X1 to X2 is an equilibrium region, and a region X2 to 2A is a restricted region. The reason why it is up to 2A is that the upper limit of the actual current IM is 2A in this embodiment.

  As shown in the figure, when the moving average of the actual current IM increases, the coefficient is set to decrease. The coefficient is set larger than 0 in the return area, and the coefficient is set smaller than 0 in the restricted area. Further, the coefficient is set as 0 in the equilibrium region between them.

  This coefficient is used to determine the upper limit value of the supply current ITF, and determines how much the upper limit value is increased or decreased per 1 s. For example, when the coefficient is −0.05 A / s, it means that the upper limit value of the supply current ITF decreases at a rate of 0.05 A per 1 s.

  That is, in the recovery region where the moving average of the actual current IM is small, this coefficient is increased from 0 and the upper limit value of the supply current ITF is gradually increased. Further, in the limited region where the moving average of the actual current IM is large, this coefficient is made smaller than 0 and the upper limit value of the supply current ITF is gradually reduced. Further, in the equilibrium region between them, this coefficient is set to 0, and the upper limit value of the supply current ITF is maintained.

The newly set upper limit value can be calculated by using a coefficient from the previously calculated upper limit value. This can be expressed in mathematical formulas.
(New upper limit) = (upper limit of previous calculation) + (coefficient) x (time interval)
It can be. Here, the time interval can be a time interval or a control cycle for setting an upper limit value. An example of the time interval for setting the upper limit value is 5 s, which is the time required to calculate the moving average.

  The supply current determination unit 166 determines the supply current ITF to be supplied to the solenoid valve 50 from the target current ITA and the upper limit value set by the upper limit setting unit 163.

Supply current determination unit 166 compares target current ITA with the upper limit value set by upper limit setting unit 163. If the target current ITA is less than or equal to the upper limit value, the supply current determination unit 166 outputs the target current ITA as the supply current ITF.
On the other hand, when the target current ITA exceeds the upper limit value, the supply current ITF is limited to the upper limit value and output.

  The supply current ITF is determined for each of the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL. However, the supply current determination unit 166 may select and output the minimum one from these (minimum select). As a result, the same supply current ITF is determined for each of the right front solenoid valve 50FR, the left front solenoid valve 50FL, the right rear solenoid valve 50RR, and the left rear solenoid valve 50RL. As a result, an effect of further stabilizing the behavior of the vehicle 100 occurs.

[Description of Operation of Supply Current Calculation Unit 160]
Next, the operation of the supply current calculation unit 160 will be described.

FIG. 7 is a flowchart illustrating the operation of the supply current calculation unit 160. The supply current calculation unit 160 repeats this operation every predetermined time.
First, the target current determination unit 161 refers to the map stored in the map storage unit 162 and calculates the target current ITA from the vehicle speed Vc (step 101).
Next, the upper limit setting unit 163 acquires the actual current IM from the detection unit 183 every predetermined time (100 ms in the above example) (step 102).

Then, the upper limit setting unit 163 determines whether or not the acquired actual current IM has reached a predetermined number of times (50 times in the above example) (step 103).
When the acquired actual current IM is less than the predetermined number of times (No in Step 103), the process returns to Step 102.
On the other hand, when the acquired actual current IM reaches a predetermined number of times (Yes in Step 103), the upper limit setting unit 163 calculates a moving average of the actual current IM (Step 104).
Note that the moving average can be calculated without waiting for the predetermined number of times to be reached without providing step 103. In this case, the moving average up to that point can be calculated until the predetermined number of times is reached.

Then, the upper limit setting unit 163 refers to the map having the contents as shown in FIG. 6 stored in the map storage unit 162, and determines the coefficient from the moving average of the actual current IM (step 105).
Then, a new upper limit value is determined by applying this coefficient to the previously determined upper limit value (step 106). At this time, the upper limit setting unit 163 increases the upper limit value when the moving average of the actual current IM is smaller than the first threshold value X1, and the moving average of the actual current IM is set as a value equal to or greater than the first threshold value X1. If it is greater than the second threshold value X2, the upper limit value is decreased. The upper limit setting unit 163 maintains the upper limit value when the moving average of the actual current IM is not less than the first threshold value X1 and not more than the second threshold value X2.

  Next, the supply current determination unit 166 compares the target current ITA calculated by the target current determination unit 161 with the upper limit value set by the upper limit setting unit 163 to determine the supply current ITF (step 107). At this time, the supply current determination unit 166 may perform the above-described minimum selection. Further, the supply current determination unit 166 determines whether the supply current ITF exceeds the upper limit (2A in the above example) of the actual current IM. Also good.

According to the supply current calculation unit 160 described above, when the moving average of the actual current IM continues to be in the limited region, the upper limit value of the supply current ITF is gradually reduced. As a result, the supply current ITF is limited and gradually decreases. The moving average of the actual current IM settles in the vicinity of the second threshold value X2 described above. Thereby, the heat generation of the coil 511 is suppressed, and the short circuit of the coil 511 is less likely to occur. That is, even when the target current ITA continues to be large, the actual current IM actually supplied to the coil 511 is limited, and heat generation of the coil 511 can be suppressed.
In addition, when the moving average of the actual current IM continues to be in the return region, the upper limit value of the supply current ITF gradually increases. Thereby, even when the supply current ITF is limited, the supply current ITF can be gradually increased to approach the target current ITA.

  According to the supply current calculation unit 160 described above, the upper limit value is directly obtained without performing a process such as estimating the temperature of the coil 511 based on the moving average of the actual current IM. Therefore, calculation of the supply current in the supply current calculation unit 160 is easier and faster.

  The suspension device 120 and the control device 150 described above can be grasped as a damping force variable damper system.

  In the example described above, the equilibrium region is provided, but it may not be provided. In this case, the first threshold value X1 and the second threshold value X2 described in FIG. 6 are the same value.

  In the example described above, the upper limit setting unit 163 sets the upper limit value based on the moving average of the actual current IM, but is not limited to this, and the upper limit value is based on the integrated value of the actual current IM. May be set. That is, the upper limit setting unit 163 sets the upper limit value based on the integrated value of the actual current acquired at a predetermined time interval (for example, every 100 ms) within a predetermined time (for example, 5 s).

  In the example described above, the upper limit setting unit 163 sets the upper limit value based on the actual current IM. However, the upper limit value is not limited to this, and is based on the supply current ITF already determined by the supply current determination unit 166. An upper limit value may be set. In this case, the upper limit setting unit 163 calculates, for example, the moving average or integrated value of the supply current ITF already determined within a predetermined time (for example, 50 s) from the supply current ITF already determined by the supply current determination unit 166. Use to set the upper limit.

  Further, in the example described above, the case where the current is supplied to the solenoid valve 50 has been described. However, even if the current is not supplied to the solenoid valve 50 such as after the ignition of the vehicle 100 is over, the upper limit by the upper limit setting unit 163 The value setting may be continued. In this case, the setting of the upper limit value by the upper limit setting unit 163 may be continued when the upper limit value at the time of ignition off is equal to or less than a predetermined value set in advance. In addition, after the upper limit value returns to the maximum value, the setting of the upper limit value by the upper limit setting unit 163 can be ended.

  Furthermore, in the example described above, the case where the vehicle 100 is a four-wheeled vehicle having four wheels has been described. However, the number of wheels is not limited to four, and any number may be used. For example, the present invention can be applied to a tricycle having three wheels or a two-wheeled vehicle having two wheels.

DESCRIPTION OF SYMBOLS 1 ... Hydraulic shock absorber, 10 ... Cylinder part, 11 ... Cylinder, 12 ... Outer cylinder, 13 ... Damper case, 20 ... Piston rod, 30 ... Piston, 40 ... Bottom valve, 50 ... Solenoid valve, 150 ... Control device, 160 ... supply current calculation unit, 161 ... target current determination unit, 163 ... upper limit setting unit, 166 ... supply current determination unit, 180 ... control unit

Claims (9)

A control device for a damping force variable damper,
A target current determining unit for determining a target current to be supplied to an electromagnetic valve that controls the damping force of the damping force variable damper;
An upper limit setting unit for setting an upper limit value of the current supplied to the solenoid valve;
A supply current determining unit for determining a supply current to be supplied to the solenoid valve from the target current and the upper limit value;
With
The upper limit setting unit is a damping force variable damper control device that determines a coefficient for increasing or decreasing the upper limit value based on the already determined supply current, and determines the upper limit value from the coefficient.   2. The damping force variable damper control device according to claim 1, wherein the upper limit setting unit determines the coefficient from a moving average of supply currents already determined within a predetermined time.   The upper limit setting unit increases the upper limit value when the already determined moving average of the supply current is smaller than a first threshold value, and is larger than a second threshold value set as a value equal to or higher than the first threshold value. 3. The damping force variable damper control device according to claim 2, wherein the upper limit value is decreased in the case.   The said upper limit setting part maintains the said upper limit value when the moving average of the supply current which has already been determined is not less than the first threshold value and not more than the second threshold value. Control device for variable damping force damper.   2. The damping force variable damper control device according to claim 1, wherein the upper limit setting unit determines the coefficient from an already determined integrated value of supply current within a predetermined time.   The upper limit setting unit increases the upper limit value when an already determined integrated value of supply current is smaller than a first threshold value, and is larger than a second threshold value set as a value equal to or higher than the first threshold value. 6. The damping force variable damper control device according to claim 5, wherein the upper limit value is decreased in the case.   The said upper limit setting part maintains the said upper limit value when the integrated value of the supply current already determined is more than the said 1st threshold value and below the said 2nd threshold value. Control device for variable damping force damper. There are a plurality of damping force variable dampers and a plurality of the solenoid valves,
The variable damping force according to any one of claims 1 to 7, wherein the supply current determination unit selects a minimum one of the supply currents determined for each of the plurality of solenoid valves. Damper control device. A damping force variable damper having a solenoid valve for adjusting damping force;
A control device for controlling the solenoid valve;
With
The control device includes:
A target current determining unit for determining a target current to be supplied to the solenoid valve;
An upper limit setting unit for setting an upper limit value of the current supplied to the solenoid valve;
A supply current determining unit for determining a supply current to be supplied to the solenoid valve from the target current and the upper limit value;
With
The upper limit setting unit is a damping force variable damper system that determines a coefficient for increasing or decreasing the upper limit value based on the already determined supply current, and determines the upper limit value from the coefficient.

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