JP2005030219A - Drive control device of actuator for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the responsiveness of an actuator for a vehicle such as a variable valve lift mechanism. <P>SOLUTION: A feedback control is performed by a drive operation amount kS obtained by adding a correction operation amount hS, for a set adding time t, to a basic operation amount fS calculated based on a control deviation ERR between the target rotating angle (target lift amount of intake valve) and the actual rotating angle (actual lift amount) of a variable valve lift mechanism (S1, S2) when the target rotating angle is changed within a specified range (S3, S11 to S4). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to drive control of an actuator for a vehicle, and more particularly to a technique for improving responsiveness.
[0002]
[Prior art]
Conventionally, a technology has been known that includes a variable valve mechanism that continuously changes the valve characteristics such as the lift amount and valve timing of the intake and exhaust valves, and controls to obtain the optimum engine torque according to the operating condition. (See Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-182563
[Problems to be solved by the invention]
In such a variable valve mechanism that continuously controls to a desired valve characteristic, when the valve characteristic is slightly changed, it is set according to the control deviation between the target valve characteristic and the actual valve characteristic. Since the driving operation amount of the variable valve mechanism is reduced, the driving force used for actual operation is reduced by being consumed by the drag force such as friction force among the generated driving force. For this reason, the response becomes slow, the convergence to the target valve characteristic is delayed, and the drivability (intake air amount control accuracy, etc.) may be impaired (see FIG. 12).
[0005]
The present invention has been made paying attention to such a conventional problem, and an object of the present invention is to make it possible to quickly converge the target value with good response even when the vehicle actuator is slightly moved.
[0006]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 sets the drive operation amount of the vehicle actuator based on the control deviation between the target value and the actual value, and temporarily adds the correction operation amount when the target value changes. The operation amount is set.
[0007]
According to such a configuration, when the target value changes, the correction operation amount is temporarily added, so that the driving force necessary for the initial operation against the frictional force or the like can be covered by the correction operation amount. Even when the value change is small and the operation amount set based on the control deviation is small, the target value is quickly converged with good response.
[0008]
In the invention according to claim 2, the correction operation amount is calculated by multiplying the change amount of the target value by the correction gain.
According to such a configuration, the correction operation amount is set according to the change amount of the target value, and it is possible to converge to the target value with good response while suppressing overshoot due to the correction operation amount.
[0009]
According to a third aspect of the present invention, the correction operation amount is temporarily added when the change amount of the target value is within a predetermined range.
According to such a configuration, when the amount of change in the target value is large, the control deviation is increased, and the drive operation amount corresponding to the control deviation is set to be large. Therefore, an overshoot is easily generated by adding a correction operation amount. Become. Therefore, if the correction operation amount is added only when the change amount of the target value is within a predetermined range, the occurrence of overshoot can be reliably avoided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a vehicle internal combustion engine provided with a variable valve lift mechanism as a vehicle actuator to which the present invention is applied. In an intake pipe 102 of the internal combustion engine 101, a throttle valve 103b is driven to open and close by a throttle motor 103a. The electronic control throttle 104 is interposed, and air is sucked into the combustion chamber 106 through the electronic control throttle 104 and the intake valve 105.
[0011]
The combustion exhaust is discharged from the combustion chamber 106 through the exhaust valve 107, purified by the front catalyst 108 and the rear catalyst 109, and then released into the atmosphere.
The exhaust valve 107 is driven to open and close by a cam 111 pivotally supported on the exhaust side camshaft 110 while maintaining a constant lift amount and operating angle (crank angle from opening to closing), while the intake valve 105 is variable. The valve lift mechanism 112 can continuously change the lift amount and the operating angle, that is, the valve opening. It should be noted that the lift amount and the operating angle can be changed simultaneously so that if one characteristic is determined, the other characteristic is also determined.
[0012]
Similarly, on the intake side, the variable is constituted by a mechanism that continuously and variably controls the rotational phase difference between the crankshaft and the intake camshaft to advance and retard the valve timing (valve opening / closing timing) of the intake valve 105. An intake side cam angle sensor 202 for detecting the rotational position of the valve timing mechanism 201 and the intake side cam shaft is provided at both ends of the intake side cam shaft.
[0013]
The control unit 114 incorporating the microcomputer is detected by an accelerator opening sensor APS116 so that a target intake air amount corresponding to the accelerator opening ACC is obtained by the opening of the throttle valve 103b and the opening characteristics of the intake valve 105. The electronic control throttle 104 and the variable valve lift mechanism 112 are controlled according to the degree of opening of the accelerator pedal.
[0014]
The control unit 114 includes an accelerator opening sensor APS116, a rotation angle sensor 127 (to be described later), the intake side cam angle sensor 202, an air flow meter 115 for detecting the intake air amount Q of the engine 101, and a rotation signal from the crankshaft. Detection signals from a crank angle sensor 117 for taking out the engine, a throttle sensor 118 for detecting the opening TVO of the throttle valve 103b, a water temperature sensor 119 for detecting the cooling water temperature Tw of the engine 101, and the like are input.
[0015]
Further, an electromagnetic fuel injection valve 131 is provided in the intake port 130 upstream of the intake valve 105 of each cylinder, and the fuel injection valve 131 is driven to open by an injection pulse signal from the control unit 114. Then, the fuel adjusted to a predetermined pressure is injected toward the intake valve 105.
[0016]
2 to 4 show the structure of the variable valve lift mechanism 112 in detail.
The variable valve lift mechanism shown in FIGS. 2 to 4 includes a pair of intake valves 105, 105, a hollow cam shaft 13 (drive shaft) rotatably supported by the cam bearing 14 of the cylinder head 11, and the cam Two eccentric cams 15 and 15 (drive cams) which are rotary cams supported by the shaft 13, a control shaft 16 rotatably supported on the same cam bearing 14 above the cam shaft 13, and the control A pair of rocker arms 18, 18 that are swingably supported on the shaft 16 via a control cam 17, and a pair of independent lifters 19, 19 disposed at the upper ends of the intake valves 105, 105 via valve lifters 19, 19. Rocking cams 20 and 20 are provided.
[0017]
The eccentric cams 15 and 15 and the rocker arms 18 and 18 are linked by link arms 25 and 25, and the rocker arms 18 and 18 and the swing cams 20 and 20 are linked by link members 26 and 26.
[0018]
The rocker arms 18 and 18, the link arms 25 and 25, and the link members 26 and 26 constitute a transmission mechanism.
As shown in FIG. 5, the eccentric cam 15 has a substantially ring shape and includes a small-diameter cam main body 15a and a flange portion 15b integrally provided on the outer end surface of the cam main body 15a. A cam shaft insertion hole 15 c is formed through the shaft, and the shaft center X of the cam body 15 a is eccentric from the shaft center Y of the cam shaft 13 by a predetermined amount.
[0019]
The pair of eccentric cams 15 are press-fitted and fixed to both outer sides of the camshaft 13 that do not interfere with the valve lifter 19 via camshaft insertion holes 15c, and the outer peripheral surface 15d of the cam body 15a is the same. The cam profile is formed.
[0020]
As shown in FIG. 4, the rocker arm 18 is bent in a substantially crank shape, and a central base portion 18 a is supported by the control cam 17 in a self-rotating manner.
A pin hole 18d into which a pin 21 connected to the tip end of the link arm 25 is press-fitted is formed at one end 18b protruding from the outer end of the base 18a, while the inner end of the base 18a is formed. A pin hole 18e into which a pin 28 connected to one end portion 26a (described later) of each link member 26 is press-fitted is formed in the other end portion 18c projecting from the portion.
[0021]
The control cam 17 has a cylindrical shape, is fixed to the outer periphery of the control shaft 16, and the position of the axis P1 is eccentric from the axis P2 of the control shaft 16 by α as shown in FIG.
[0022]
As shown in FIGS. 2, 6, and 7, the rocking cam 20 has a substantially horizontal U shape, and a cam shaft 13 is fitted into a substantially annular base end portion 22 so as to be rotatably supported. A support hole 22a is formed through, and a pin hole 23a is formed through the end 23 located on the other end 18c side of the rocker arm 18.
[0023]
Further, a base circle surface 24a on the base end portion 22 side and a cam surface 24b extending in an arc shape from the base circle surface 24a toward the end edge side of the end portion 23 are formed on the lower surface of the swing cam 20. The circular surface 24 a and the cam surface 24 b come into contact with predetermined positions on the upper surfaces of the valve lifters 19 in accordance with the swing position of the swing cam 20.
[0024]
That is, when viewed from the valve lift characteristics shown in FIG. 8, as shown in FIG. 2, the predetermined angle range θ1 of the base circle surface 24a becomes the base circle section, and the predetermined angle range θ2 from the base circle section θ1 of the cam surface 24b changes. This is a so-called ramp section, and further, a predetermined angle range θ3 from the ramp section θ2 of the cam surface 24b is set to be a lift section.
[0025]
The link arm 25 includes an annular base portion 25a and a projecting end 25b projecting at a predetermined position on the outer peripheral surface of the base portion 25a. At the center position of the base portion 25a, the cam body of the eccentric cam 15 is provided. A fitting hole 25c is formed in the outer peripheral surface of 15a so as to be freely rotatable, and a pin hole 25d through which the pin 21 is rotatably inserted is formed in the protruding end 25b.
[0026]
Further, the link member 26 is formed in a straight line having a predetermined length, and circular pin ends 26a and 26b have pin holes 18d in the other end 18c of the rocker arm 18 and the end 23 of the swing cam 20, respectively. , 23a, and pin insertion holes 26c and 26d through which end portions of the pins 28 and 29 are rotatably inserted are formed.
[0027]
In addition, snap rings 30, 31, and 32 that restrict the axial movement of the link arm 25 and the link member 26 are provided at one end of each pin 21, 28, and 29.
[0028]
In the above configuration, the lift amount varies as shown in FIGS. 6 and 7 depending on the positional relationship between the axis P2 of the control shaft 16 and the axis P1 of the control cam 17, and the control shaft 16 is driven to rotate. As a result, the position of the axis P2 of the control shaft 16 with respect to the axis P1 of the control cam 17 is changed.
[0029]
The control shaft 16 is driven to rotate within a predetermined rotation angle range between a minimum angle position and a maximum angle position defined by a stopper by a DC servo motor (actuator) 121 with the configuration shown in FIG. By changing the operating angle of the control shaft 16 by the actuator 121, the lift amount and the operating angle of the intake valve 105 change continuously (see FIG. 9).
[0030]
In FIG. 10, the DC servo motor 121 is arranged so that its rotation shaft is parallel to the control shaft 16, and a bevel gear 122 is pivotally supported at the tip of the rotation shaft.
On the other hand, a pair of stays 123a and 123b are fixed to the tip of the control shaft 16, and a nut 124 is swingably supported around an axis parallel to the control shaft 16 connecting the tips of the pair of stays 123a and 123b. The
[0031]
A bevel gear 126 meshed with the bevel gear 122 is pivotally supported at the tip of the screw rod 125 meshed with the nut 124, and the screw rod 125 is rotated by the rotation of the DC servo motor 121. The position of the nut 124 that meshes with the 125 is displaced in the axial direction of the screw rod 125 so that the control shaft 16 is rotated.
[0032]
Here, the direction in which the position of the nut 124 is brought closer to the bevel gear 126 is a direction in which the lift amount is reduced, and conversely, the direction in which the position of the nut 124 is moved away from the bevel gear 126 is a direction in which the lift amount is increased. .
[0033]
As shown in FIG. 10, a potentiometer-type rotation angle sensor 127 that detects the rotation angle of the control shaft 16 is provided at the tip of the control shaft 16, and the actual rotation detected by the rotation angle sensor 127. The control unit 114 feedback-controls the DC servo motor 121 so that the angle matches the target rotation angle. Here, since the lift amount and the operating angle can be changed simultaneously by the rotation angle control of the control shaft 16, the rotation angle sensor 127 detects the operating angle of the intake valve 105 and simultaneously detects the lift amount, that is, the opening degree. It is.
[0034]
The variable valve lift mechanism 112 changes the lift amount (operating angle) of the intake valve 105 to control the intake amount. That is, the control target value of the variable valve lift mechanism 112 that is the control object of the present invention is the target rotation angle of the control shaft 16 and simultaneously the target lift amount (target operation angle) of the intake valve.
[0035]
FIG. 11 shows a flowchart of feedback control of the variable valve lift mechanism 112.
In step 1, a difference between the target rotation angle TGVEL of the control shaft 16 and the actual rotation angle REVEL detected by the rotation angle sensor 127, that is, a control deviation ERR (= TGVEL−RAVE) is calculated.
[0036]
In step 2, a basic operation amount (feedback control amount) fS is calculated based on the control deviation ERR. Specifically, for example, a proportional operation amount P calculated by multiplying a proportional gain g _p to the control deviation ERR, after also integral calculation control deviation ERR, integral operation amount I and calculated by multiplying the integral gain g _i after the same control deviation ERR and differential operation to calculate the basic operation value fS by adding the derivative operation amount D is calculated by multiplying the differential gain g _d.
[0037]
In step 3, it is determined whether the target rotation angle TGVEL has changed.
When it is determined in step 3 that the target rotation angle TGVEL has changed, the process proceeds to step 4 where an effective flag is set assuming that the correction operation amount calculated as described later is valid (adding), and then step 5 is performed. Thus, the correction operation amount hS is calculated as follows.
[0038]
hS = ΔTGVEL × Gs
hS: correction operation amount ΔTGVEL: target rotation angle change amount Gs: correction gain In step 6, the correction operation amount hS calculated in step 5 is added to the basic operation amount fS calculated in step 2 to obtain a final value. This is set as the drive operation amount KS of the control shaft 16.
[0039]
On the other hand, when it is determined in step 3 that the target rotation angle TGVEL has not changed, the routine proceeds to step 7 where it is determined whether the correction operation amount is being added based on the value of the valid flag, and it is determined that it is being added. If YES in step S8, the flow advances to step 8 to determine whether the set additional time t of the correction operation amount has elapsed.
[0040]
When it is determined in step 8 that the set additional time t is not yet elapsed, the process proceeds to step 6 to continue setting the final drive operation amount KS by adding the correction operation amount hS to the basic operation amount fS. To do.
[0041]
When it is determined in step 8 that the set additional time t has elapsed, the process proceeds to step 9 to clear the valid flag, and then proceeds to step 10 to determine the basic operation amount fS as the final drive operation. Set as quantity KS. Thereafter, in step 7, it is determined that the corrected operation amount is not being added based on the cleared valid flag, and the process proceeds to step 10, and the setting of setting the basic operation amount fS as the final drive operation amount KS is continued.
[0042]
In this way, when the target rotation angle TGVEL changes, the correction operation amount hS is added to the basic operation amount fS for the set additional time t, whereby the change amount of the target rotation angle TGVEL is small and the basic operation amount fS. Even if is set to be small, the amount corresponding to the drag force such as friction can be covered by the correction operation amount hS. As a result, the basic operation amount fS set according to the control deviation ERR is controlled by excluding the drag force. It is possible to contribute to the driving force of the substantial rotation operation of the shaft 16, and to quickly converge to the target rotation angle TGVEL with good response.
[0043]
FIG. 12 shows the operation of this embodiment in comparison with a conventional example in which no correction operation amount is added. By adding the correction operation amount, the convergence time to the target rotation angle can be greatly reduced. Thereby, drivability (intake air amount control accuracy, etc.) can be greatly improved.
[0044]
The correction operation amount is set in proportion to the target rotation angle change amount as described above. When the change amount is small, if the correction operation amount is excessive, the target rotation angle is overshot immediately. This is because it becomes easier. If it is set in proportion to the target rotation angle change amount, even if the rotation angle (valve lift amount) is changed finely, the minimum correction operation amount should be set so as to converge quickly without overshooting. Can do.
[0045]
Further, in this embodiment, the setting addition time for adding the correction operation amount is constant, but instead of setting the correction operation amount variably according to the target rotation angle change amount, or in combination with this, the target rotation angle change amount is set. Accordingly, the correction operation amount setting additional time may be variably set (larger as the target rotation angle change amount is larger).
[0046]
On the other hand, as described above, when the amount of change in the target rotation angle is sufficiently large, a large control deviation is generated, and the operation amount set according to the control deviation is originally large and is consumed by a drag force such as friction. Since a large amount of operation remains even if is removed, it can be quickly converged to the target rotation angle with good response. Here, even when the control deviation is large, if the correction operation amount is added, the operation amount may be too large and an overshoot may occur. This is because the drag force such as friction is large at the beginning of movement, but decreases once it starts to move, and this is why the correction operation amount is given only for the initial predetermined time.
[0047]
Therefore, in the second embodiment, as shown in the flowchart of FIG. 13, when the target rotation angle changes, it is determined in step 11 whether the change amount of the target rotation angle is within a predetermined range. In the case of the size, the process proceeds to step 10 and the correction operation amount is not added, and the process proceeds to step 3 and the correction operation amount is added only when the size is smaller than a predetermined value.
[0048]
In this way, when the change in the target rotation angle is large, the addition of the correction operation amount is prohibited, so it is possible to reliably prevent the occurrence of overshoot due to the operation amount becoming too large, and the target rotation angle smoothly Can converge.
[0049]
In the third embodiment, instead of determining the magnitude of the target change amount for the same purpose as in the second embodiment, the judgment is made based on the magnitude of the control deviation. As shown in the flowchart of FIG. On the other hand, if it is determined in step 21 that the control deviation is not within the predetermined range, the process proceeds to step 10 and the correction operation amount is not added, and the process proceeds to step 3 only when the magnitude is within the predetermined range. The operation amount is added. The effect is the same as in the second embodiment.
[0050]
As a fourth embodiment, as shown in the flowchart of FIG. 15, after the correction operation amount hS is calculated in the same manner in step 5, the correction operation amount hS is limited to a predetermined range in steps 31 and 32. It is good. That is, even if the amount of change in the target rotation angle TGVEL increases by a predetermined value or more, the correction operation amount hS is given within a predetermined range, so that overshoot can be prevented. Further, there is no step difference in the operation amount around the predetermined value of the target rotation angle change amount.
[0051]
Further, as the fifth embodiment, as shown in the flowchart of FIG. 16, when the target rotation angle TGVEL is changed, the change amount (difference from the previous value) of the actual rotation angle REVEL is within a predetermined range in step 41. Only when it is determined that there is a predetermined range, the process proceeds to step 4 to add the correction operation amount. As described above, a drag force such as friction is greatly generated at the beginning of movement, and decreases once the movement starts (static friction force> dynamic friction force). That is, the drag caused by friction is generated only when the actual rotational angle REVEL changes less than a predetermined value or when it is in a low speed state close to the stop. Therefore, only in this case, the correction operation amount hS is added to enhance the response. In this case, the addition of the correction operation amount hS is prohibited to avoid the occurrence of unnecessary overshoot.
[0052]
The present invention can be applied to various actuators other than the variable valve lift mechanism described above as a vehicle actuator. Particularly, when the amount of change in the target value is small, the ratio of the drag due to friction to the required driving force is large. When applied to, the effect is great.
[0053]
Further, technical ideas other than the claims that can be grasped from the above embodiment will be described together with the effects thereof.
(A) In the vehicle actuator control device according to any one of claims 1 to 3, when the control deviation is within a predetermined range, the correction operation amount is temporarily added. It is characterized by.
[0054]
According to this configuration, when the control deviation is not within the predetermined range, addition of the correction operation amount is prohibited, so that it is possible to reliably prevent the occurrence of overshoot due to the operation amount becoming too large, and to smoothly achieve the target rotation angle. Can converge.
[0055]
(B) In the vehicle actuator control device according to any one of claims 1 to 3, the correction operation amount is limited to a predetermined range.
According to such a configuration, since the correction operation amount is limited within a predetermined range, it is possible to reliably prevent the occurrence of overshoot due to an excessive increase in the operation amount and smoothly converge to the target rotation angle.
[0056]
(C) In the control device for a vehicle actuator according to any one of claims 1 to 3, (a), and (b), the target value change only when the change amount of the actual value is within a predetermined range. It is characterized in that a correction operation amount at the time is temporarily added.
[0057]
According to such a configuration, it is possible to increase the response by adding a correction operation amount only when a drag due to friction is generated, and to prevent the occurrence of unnecessary overshoot in other cases by prohibiting the addition of the correction operation amount.
[0058]
(D) In the control device for a vehicle actuator according to any one of claims 1 to 3, (A), (B), and (C), the vehicle actuator operates an operation valve of an internal combustion engine. It is a variable valve mechanism that continuously changes the characteristics.
[0059]
According to this configuration, the responsiveness when the operating characteristics such as the valve lift amount and valve timing are changed by the variable valve mechanism is improved.
(E) The control device for a vehicle actuator according to claim 3 or (c), wherein the predetermined range of the change amount of the target value or the actual value is an absolute value of the change amount.
[0060]
According to such a configuration, it is possible to deal with both changes in the positive direction and the negative direction of the target value or the actual value.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of an internal combustion engine provided with a variable valve control apparatus according to the present invention.
FIG. 2 is a cross-sectional view showing a variable valve mechanism (AA cross-sectional view in FIG. 3).
FIG. 3 is a side view of the variable valve mechanism.
FIG. 4 is a plan view of the variable valve mechanism.
FIG. 5 is a perspective view showing an eccentric cam used in the variable valve mechanism.
6 is a cross-sectional view showing the operation of the variable valve mechanism during low lift (cross-sectional view taken along the line BB in FIG. 3).
7 is a cross-sectional view (cross-sectional view taken along the line BB in FIG. 3) showing the operation of the variable valve mechanism during high lift.
FIG. 8 is a valve lift characteristic diagram corresponding to the base end surface of the swing cam and the cam surface in the variable valve mechanism.
FIG. 9 is a characteristic diagram of valve timing and valve lift of the variable valve mechanism.
FIG. 10 is a perspective view showing a rotation driving mechanism of a control shaft in the variable valve mechanism.
FIG. 11 is a flowchart of feedback control in the first embodiment.
FIG. 12 is a view showing the effect of the embodiment in comparison with the conventional example.
FIG. 13 is a flowchart of feedback control in the second embodiment.
FIG. 14 is a flowchart of feedback control in the third embodiment.
FIG. 15 is a flowchart of feedback control in the fourth embodiment.
FIG. 16 is a flowchart of feedback control in the fifth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 13 ... Cam shaft 15 ... Eccentric cam 16 ... Control shaft 17 ... Control cam 18 ... Rocker arm 20 ... Swing cam 25 ... Link arm 101 ... Internal combustion engine 104 ... Electronic control throttle 105 ... Intake valve 112 ... Variable valve lift mechanism 114 ... Control Unit 115 ... Air flow meter 116 ... Accelerator opening sensor 117 ... Crank angle sensor 118 ... Throttle sensor 121 ... DC servo motor 127 ... Rotation angle sensor

Claims (3)

In a control device that feedback-controls a drive operation amount of a vehicle actuator based on a control deviation between a target value and an actual value.
A drive control apparatus for a vehicle actuator, wherein the operation amount is set by temporarily adding a correction operation amount when the target value changes. The drive control apparatus for a vehicle actuator according to claim 1, wherein the correction operation amount is calculated by multiplying a change amount of the target value by a correction gain. The vehicle actuator drive control device according to claim 1, wherein the correction operation amount is temporarily added when the change amount of the target value is within a predetermined range.

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