JPH09166160A - Clutch control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform engagement and disengagement of a clutch without the occurrence of a shock by a method wherein control characteristics due to linear properties between the fluid pressure of a fluid pressure type clutch actuator and a clutch stroke are improved. SOLUTION: A clutch control device comprises a friction clutch; a clutch actuator 6 to drive a friction clutch by a fluid pressure fed from a fluid pressure source; and a feedback control means F to regulate the actual stroke of a friction clutch by controlling operation of the clutch actuator 6 so that the actual stroke of the friction clutch approaches a target stroke set based on a vehicle state. A PID control factor computed by a PID computing means 44 arranged at the feedback control means F is set in such a manner to be differed between a case wherein the actual stroke is closer to the connection side of the friction clutch than a reference value and a case wherein the PID control factor is closer to the release side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch control device for controlling the operation of a friction clutch that connects and disconnects an engine and a power transmission system, and more particularly, to improve the operation control of the friction clutch while using PID control. , A clutch control device.

[0002]

2. Description of the Related Art In recent years, automatic transmissions having a torque converter have become widespread in passenger cars, and a driver has to operate a clutch or a shift lever for shifting gears after starting or stopping. There is no need to do such things, and the facilitation and automation of automobile driving operations are being promoted.

On the other hand, in large vehicles such as trucks and buses, the cost of a torque converter type automatic transmission for large vehicles is high, and the power transmission efficiency is lower than that of a manual transmission, resulting in lower fuel consumption and output. Because of what you do,
It is not widely used in the market despite its great operational advantages. Recently, conventional friction clutches and manual transmissions can be driven using actuators while using fluid pressures such as hydraulic pressure and air pressure used for brakes as drive sources, and each actuator is electronically controlled. A system adapted to do so has also been provided.

Particularly, in the conventional manual connection operation of the friction clutch, the driver is required to have skill such as subtly changing the connection speed of the clutch depending on the size of the loaded weight or road surface conditions such as a steep slope or a flat road. It was an operation. For this reason,
In particular, it is not easy for a female driver, an elderly driver or a beginner driver to operate the vehicle in recent years, and there is an increasing demand for improving the operability of the vehicle by automating the clutch.

Therefore, various techniques for automating the clutch have been developed. Even in such a conventional device for automating the clutch (that is, the clutch control device), the load weight and the road condition are not changed. Therefore, the control is not always appropriately performed, and when the clutch is engaged or disengaged (disengaged) at the time of starting or shifting, a clutch engagement / disengagement shock due to a sudden connection or the like unexpected by the driver is caused.

As one means for solving such a problem,
Recently, for example, as shown in FIG. 7, feedback control using a PID circuit has been adopted. That is, as shown in FIG. 7, the air tank 7 as a fluid pressure source
An electromagnetic valve 101 whose air pressure can be adjusted according to an input signal is interposed between the clutch actuator 6 and the clutch actuator 6.
On the other hand, the value of the target stroke of the clutch set based on various conditions such as accelerator opening and clutch transmission torque,
The detection value of the clutch stroke sensor 104 (that is, the value of the actual stroke) installed at the output portion of the clutch actuator 6 is input to the PID circuit 102, and this P
The PID output from the ID circuit 102 is amplified by the amplifier 103 and output to the solenoid valve 101 as a control signal.

In the PID circuit 102, the following calculation is generally performed to perform feedback control on the clutch stroke. That is, for the deviation u between the actual stroke value detected by the clutch stroke sensor 104 and the target stroke value, PI
The D output value y is calculated.

Y = Kp · u + Ki · ∫udt + KD (du / dt) Here, the PID output y is a stroke increase command value of the clutch, and this PID output y is added to the actual stroke detected by the clutch stroke sensor 104. The added amount becomes the stroke amount command value. Further, Kp is a proportional operation coefficient, Ki is an integral operation coefficient, KD is a differential operation coefficient,
Each is appropriately initialized. These coefficients Kp, K
i and KD are also called PID control coefficients or PID constants.

Regarding such a technique, for example, Japanese Patent Application Laid-Open No. 64-41646 discloses a technique for continuously switching PID control coefficients.
Japanese Patent Laid-Open No. 77171 discloses a technique for avoiding deviation accumulation by an integrator of PID control during a time delay caused by a stroke time of a clutch piston or the like regarding hydraulic start clutch control. In addition, JP-A-4
Japanese Patent Application Laid-Open No. 19340 and Japanese Patent Application Laid-Open No. 4-159437 disclose a technique of performing PID control for rotation speed control in an internal combustion engine. Furthermore, JP-A-4-25
Japanese Patent No. 2857 discloses a technique of performing PID control on an injection timing control device of a fuel injection pump.

[0010]

However, the feedback control of the clutch using such a conventional PID circuit has the following problems. That is, the clutch actuator 6 such as a pneumatic actuator
Generally has the characteristics shown in FIG.

FIG. 2 shows the clutch stroke realized with respect to the supply air pressure by taking the clutch stroke on the horizontal axis and the air pressure on the vertical axis. As shown in FIG. 2, the clutch actuator 6 produces hysteresis characteristics in the direction of increasing the stroke and the direction of decreasing the stroke due to the working fluid having compressibility.

Further, regarding the air pressure in the stroke region that does not exceed the point A in the figure, a substantially linear relationship is established regarding the stroke, but regarding the air pressure in the stroke region that exceeds the point A in the figure, there is a correlation regarding the stroke. Changes greatly. Therefore, for example, when the clutch stroke does not exceed point A in the figure, even if good control can be performed by PID calculation, the PID control coefficient suitable for the range in which the clutch stroke does not exceed point A
When control is performed in a large range so that the clutch stroke exceeds point A in the figure, the actual stroke characteristic b overshoots because the PID output near the clutch disengagement point is too large as shown by the characteristic a in FIG. .

Therefore, if the feedback control of the clutch is performed with the same correlation over the entire clutch stroke, that is, with the same PID control coefficient, there is a problem that the responsiveness and the settability of the clutch are deteriorated. In other words, the conventional technique cannot sufficiently improve the control characteristic due to the non-linearity between the fluid pressure and the clutch stroke in such a fluid pressure clutch actuator.

The present invention has been devised in view of the above problems, and improves the control characteristics due to the non-linearity of the fluid pressure and the clutch stroke in the fluid pressure type clutch actuator, and disengages the clutch without shock. It is an object of the present invention to provide a clutch control device capable of realizing contact.

[0015]

In the clutch control device according to the present invention, the PID control coefficient in the PID calculating means is set to the case where the clutch stroke is closer to the friction clutch connection side than the reference value and to the release side. By setting different settings depending on the case, it is possible to realize clutch stroke control suitable for the connection side and the release side.

That is, the clutch control device of the present invention is
A friction clutch that can connect and disconnect the engine and power transmission system,
A clutch actuator that drives the friction clutch by the fluid pressure supplied from a fluid pressure source, and the clutch actuator so that the actual stroke of the friction clutch approaches a target stroke of the friction clutch that is set based on the vehicle state. In the clutch control device having a feedback control means capable of controlling the operation of the above, and adjusting the actual stroke, the feedback control means includes a PID calculating means, and the PID control coefficient by the PID calculating means is equal to the actual stroke. It is characterized in that the friction clutch is set to be different from the reference value on the connection side and on the disengagement side.

The reference value is preferably the actual stroke when the ratio of the change in the fluid pressure to the change in the actual stroke changes. Also, the above PID
The calculating means calculates a difference between the actual stroke and the target stroke by a first coefficient, a value obtained by integrating the difference by time with a second coefficient, and the difference by time. And a calculation means for calculating a stroke operation amount, which is a sum of a value obtained by multiplying a value obtained by differentiating with respect to
The first coefficient when the PID control coefficient is configured from the first coefficient, the second coefficient, and the third coefficient, and the actual stroke is closer to the friction clutch connection side than the reference value. , The values of the second and third coefficients are smaller than the values of the first, second, and third coefficients when the actual stroke is on the release side of the friction clutch with respect to the reference value. Is preferably set to.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a clutch control device as an embodiment of the present device, FIG. 1 is a block diagram schematically showing the configuration of the main part thereof, FIG. 2 is a graph showing its actuator characteristics, and FIG. FIG. 4 is a graph showing the PID output characteristic, FIG. 4 is a flow chart for explaining the operation, FIG. 5 is a graph showing the operation state, and FIG. 6 is a schematic view showing a mechanical automatic transmission device equipped with this clutch control device. It is a block diagram.

The present clutch control device is provided, for example, in a mechanical automatic transmission device as shown in the block diagram of FIG. Such a mechanical automatic transmission device is suitable for large vehicles such as trucks and buses. Here, the system configuration of the mechanical automatic transmission device shown in FIG. 6 will be described. The torque disconnecting clutch mechanism (hereinafter referred to as a clutch) 1 and the transmission 2 are the dry type single plate frictions similar to those of a manual vehicle. It consists of a clutch (friction clutch) and a synchronous mesh transmission.

Further, the present clutch control device includes a clutch mechanism having a friction clutch 1, a fluid pressure type actuator 6 as a clutch actuator which will be described later, and feedback control means for controlling the operation of the clutch actuator as described later to adjust the actual stroke thereof. It is composed of F and. Referring again to FIG. 6, the engine 3
By controlling the injection pump 4 with a control signal from the electronic governor control unit 5, a desired operating state is maintained.

The clutch 1 and the transmission 2 are operated by a fluid pressure type actuator 6 as a clutch actuator and a gear shift unit 15 as a gear shift means which are operated by fluid pressure, and air pressure is used as the fluid pressure. The actuator 6 is also referred to as a pneumatic actuator. In particular, here, as the air source (fluid pressure source), an air pressure source for brake operation is used.

That is, a main air tank 7 is provided as an air pressure source for brake operation, and is configured to supply operation air to the wheel cylinders 10 and 11 via air masters 8 and 9 to perform the operation. There is.
These are controlled by a brake valve (not shown), but when the vehicle starts on a slope, automatic braking is performed by the operation of the magnet valves 12 and 13 for auxiliary brakes for starting a slope.

The operating air in these braking systems is backed up by the emergency air tank 14. Further, the working air of the braking system is supplied to the pneumatic actuator 6 and the gear shift unit 15, and the respective driving operations are configured to realize a required operating state.

The operations of the pneumatic actuator 6 and the gear shift unit 15 are controlled by the mechanical automatic transmission control unit 16. The control unit 16 has
Depression amount of accelerator pedal 17 (hereinafter referred to as accelerator opening degree), select signal of selector 18, push button 1
9, a hill start auxiliary braking signal is input, and an engine speed from the electronic governor control unit 5, a clutch speed from the clutch 1, and a transmission gear position and vehicle speed from the transmission 2 are input. .

The control unit 16 has a required microcomputer, and has a clutch control function (clutch control means) so as to control the clutch 1 and the transmission 2 on the basis of the above detection signals.
16A and a transmission control function (transmission control means) 16B. The control unit 16 outputs an accelerator signal to the electronic governor control unit 5, a clutch connection / disconnection control signal from the clutch control means 16A to the clutch 1, and a transmission gear position signal from the transmission control means 16B to the gear shift unit 15. The required control signals are also output to other braking systems. In addition, 39 in FIG. 6 is an emergency switch box.

Further, in this device, all the intentions of the driver are transmitted by the accelerator opening and the position of the selector 18, and the selector 18 after the engine is started.
To the "D" (Drive) range or "Pw" (Pow
er) range, the gear enters "2nd",
When the accelerator pedal 17 is depressed in this state, the starting operation is started.

This starting operation is accompanied by the engaging operation of the clutch 1. The clutch control for engaging the clutch 1 is engine control corresponding to the accelerator opening so that the starting operation can be smoothly performed without shock. It is supposed to be done in conjunction with. Then, also during the subsequent traveling, clutch control and shift (shifting of shift speed) control are performed in conjunction with engine control in correspondence with the accelerator opening. For this reason, these control systems store maps regarding shift speed selection data and clutch stroke data corresponding to the accelerator opening. Using such maps, clutch control, shift control, engine The controls are linked to each other.

By the way, the clutch 1 uses a dry single plate clutch as a solid friction clutch similar to a manual vehicle, but instead of the clutch booster of the manual vehicle, an electric-pneumatic servo clutch actuator 6 is provided. There is. Then, the clutch actuator 6
Is the clutch control means 16 of the control unit 16.
A control signal from A is used to open and close four solenoid valves (not shown) of two systems, one for connection and the other for connection.

Further, the fine adjustment of the clutch 1 at the time of starting or shifting is configured to be performed by duty control for opening and closing the solenoid valve in a short cycle. By adjusting the duty ratio, the clutch actuator 6 can be operated. The operating speed can be adjusted and the clutch stroke itself can be controlled. By the way, when focusing on the present clutch control device, the clutch stroke sensor 104 configured as shown in FIG. 1 detects a clutch stroke by the clutch actuator 6, and a target stroke is achieved based on a detection signal of the clutch stroke sensor 104. Feedback control means F for performing PID feedback control is provided.

That is, by the required operation of the solenoid valve 101 based on the control signal of the feedback control means F, the amount of air supplied from the air tank 7 (see FIG. 6), which is the air source, is duty-controlled, and the air pressure as the clutch actuator is controlled. The actuator 6 is driven to realize a desired clutch stroke. Here, the spool type solenoid valve 43 has a PID control circuit (PI
The output of the D control means) 44 is amplified by the amplifier 45 and input.

Further, the detection signal of the clutch stroke sensor 104 is input to the PID control circuit 44 as a feedback signal, and the pneumatic actuator 6 as a clutch actuator receives the detection signal of the clutch stroke sensor 104. Feedback control is performed based on this. The pneumatic actuator 6 as a clutch actuator in the control means F has the characteristics shown in FIG.

FIG. 2 shows the clutch stroke realized with respect to the supply air pressure, with the horizontal axis representing the clutch stroke and the vertical axis representing the air pressure. As shown in FIG. 2, the pneumatic actuator 6 as a clutch actuator has a characteristic that hysteresis is generated in a direction in which the working fluid has a compressibility and in a direction in which the stroke increases and a direction in which the stroke decreases. Has become.

Further, in the stroke region which does not exceed the point indicating the reference value of the actual stroke, that is, the point A (point of the stroke A) in the figure, the air pressure and the stroke have a substantially linear relationship. For the air pressure in the stroke region that exceeds the point A, the linear relationship does not hold. That is, the characteristics from the points t _{1 to} t ₂ and the characteristics from t _{3 to} t ₄ in FIG. 2 are substantially flat characteristics, and a wide range of strokes correspond to the same air pressure.

Control is performed by the pneumatic actuator 6 as a clutch actuator having such characteristics, and the PID circuit 44 is constructed as follows for this control. That is, the PID output y according to the following equation is performed for the deviation u between the actual stroke that is the output of the clutch stroke sensor 104 and the target stroke that is output from the control unit 16.

Y = Kp · u + Ki · ∫udt + KD (du / dt) Here, the PID output y is a stroke increase command value of the clutch, and this PID output y is added to the actual stroke detected by the clutch stroke sensor 104. The added amount becomes the stroke amount command value. In addition, the first term (Kp ·
u) is the proportional motion (P motion), and the second term (Ki∫)
udt) is the integral operation (I operation), and the third term (KD
(Du / dt) is the differential operation (D operation). Kp, Ki and KD are a proportional action coefficient, an integral action coefficient and a derivative action coefficient, respectively, which are appropriately initialized. These coefficients Kp, Ki, KD are also called PID control coefficients or PID constants.

Then, each coefficient (constant) Kp, Ki, KD
Each has a first coefficient and a second coefficient, and the combination of the first respective coefficients constitutes a first PID constant (first PID control coefficient), and the combination of the second respective coefficients. Constitutes a second PID constant (second PID control coefficient). Here, the first PID constant is set for feedback control when the clutch stroke is on the clutch connection side with respect to the reference value (that is, point A in FIG. 2). A point indicating the reference value of the actual stroke, that is, point A (point of stroke A) in the figure. The second PID constant is that the clutch stroke is on the clutch release (disengagement) side of the reference value (point A). Is set for feedback control in.

In particular, normally, the return spring
In order to open the clutch urged in the connecting direction at a speed higher than the connecting speed and overcoming the return spring force, the PID control coefficient (the first stroke) when the actual stroke is on the connecting side with respect to the reference value PID constant of 1)
Is set to be smaller than the value of the PID control coefficient (second PID constant) when the actual stroke is on the open side of the reference value.

Then, the first PID constant and the second PID constant
The PID constant of the above is switched and set in the feedback control means F based on the clutch stroke. By the way, the clutch control means 16A (see FIG. 6) is provided with a storage means 42 for storing the clutch stroke detected by the clutch stroke sensor 104 in order to switch and set the PID constant. The clutch stroke value at the time of detecting a predetermined clutch stroke change based on the value is set as the predetermined stroke to be switched.

The above-mentioned predetermined clutch stroke change is detected when the output of the PID control circuit 44 changes based on the moving speed of the clutch stroke. Since the clutch control device of the present embodiment is configured in this way, the first and second PID constants are set, for example, according to the flowchart of FIG.

First, in step S1, PID output y
It is determined whether or not the change rate has changed more than a predetermined value in a state where the change rate is positive. That is, the changing speed is constantly calculated and monitored based on the stored value of the clutch stroke in the storage means 42, and the point B at time t ₁ in FIG.
In the state where the changing speed is positive, as in step S1, when the changing speed changes significantly (the slope changes), step S
The "YES" route is taken from 1 and step S2 is executed.

In step S2, the actual stroke at that time (this corresponds to stroke A) S
B is stored. Then, the step S3 is executed, then the actual stroke is whether the actual stroke or SB greater than stored is determined, is in a state where the actual stroke is increased in the state at time t ₁ ~t ₂ in FIG. 3 Therefore, the stroke 5 is executed by taking the “NO” route.

In step S5, the second PID constant is set, and PID control is performed according to the number of identifications. Therefore, the switching setting from the first constant to the second constant is performed. As a result, the increase rate of the PID output is reduced from the point B, and as shown in FIG.
The increase state of the actual stroke is also reduced, and the characteristic of the solid line when the constant is not changed is changed to the characteristic of the dotted line when the constant is changed.

Therefore, the overshoot that occurs in the characteristic when the constant is not switched does not occur like the dotted line characteristic when the constant is switched. As a result, the disengagement operation of the clutch device can be performed with good convergence without generating an impact.

In the PID control circuit 44, the change in the PID output depending on the changing speed of the actual stroke is
In particular, it is caused largely by the influence of the differential action
By switching the PID constant, the state can be eliminated and the control operation can be improved. On the other hand, when the clutch device is changed from the disengaged state to the engaged state, the speed of change of the PID output is negative, so that the “NO” route is taken in step S1 and the PID constant is switched to the first PID constant in step S4. Feedback control that is consistent with the linear characteristics in 2 is performed.

The above-mentioned change point of the stroke change speed corresponds to a point near the half-clutch where the spring constant of the clutch device changes. In this way,
Deterioration of responsiveness and settling property, which occurs when PID control is performed with the same PID control coefficient (PID constant) over the entire clutch stroke, can be prevented.

Further, while realizing good PID control in the area not exceeding point A in FIG. 2, PID control in the clutch stroke area exceeding point A is performed by suppressing PID output near the clutch disengagement point. It becomes possible to carry out without overshoot. The present clutch control device is not limited to the mechanical automatic transmission as shown in the embodiment, but is applied to other transmissions, and is not limited to the transmission, and is also applied to a place for connecting and disconnecting other power. can do.

[0047]

As described in detail above, according to the clutch control device of the present invention, the following effects and advantages can be obtained. That is, when the PID control is performed with the same coefficient over the entire clutch stroke,
It becomes possible to prevent deterioration of responsiveness and settling property.

Then, while realizing good PID control in a small clutch stroke range, PID control in a large clutch stroke range is performed by suppressing PID output in the vicinity of the clutch disengagement point to prevent stroke overshoot. You will be able to do it in. Also, good P over the entire clutch stroke
By performing the ID feedback control, it is possible to avoid a shock when the clutch is engaged and disengaged, and a driving feeling similar to that of an automatic transmission can be obtained by using a normal fluid clutch.

Further, the reference value of the clutch stroke for changing the PID control coefficient can be reliably determined, and the accuracy of clutch stroke control can be improved. In particular, by adopting the actual stroke when the ratio of the change in the fluid pressure to the change in the actual stroke changes as the reference value, the reference value of the clutch stroke can be determined more reliably and easily.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a main part of a clutch control device as an embodiment of the present invention.

FIG. 2 is a graph showing characteristics of an actuator of a clutch control device according to an embodiment of the present invention.

FIG. 3 is a graph showing a PID output characteristic of a clutch control device as an embodiment of the present invention.

FIG. 4 is a flowchart for explaining the operation of the clutch control device as one embodiment of the present invention.

FIG. 5 is a graph showing an operating state of the clutch control device according to the embodiment of the present invention.

FIG. 6 is a schematic block diagram showing an overall configuration of a mechanical automatic transmission device including a clutch control device as an embodiment of the present invention.

FIG. 7 is a block diagram schematically showing a main part of a clutch control device as a conventional example.

[Explanation of reference numerals] 1 clutch mechanism (clutch) for torque connection and disconnection 2 transmission 3 engine 4 injection pump 5 electronic governor control unit 6 fluid pressure type actuator as a clutch actuator (pneumatic actuator 9 7 fluid pressure source for brake operation (pneumatic pressure) Source) Main air tank 8,9 Air master 10,11 Wheel cylinder 12,13 Magnet valve for slope start auxiliary brake 14 Air tank for emergency 15 Gear shift unit as gear shift means 16 Control unit for mechanical automatic transmission for automobile 16A Clutch control means 16B Transmission control means 17 Accelerator pedal 18 Selector 19 Push button 39 Emergency switch box Second storage means 43 spool type solenoid valve 44 PID controller (PID controller) 45 amp 104 clutch stroke sensor F feedback control means

Claims (3)

[Claims] 1. A friction clutch capable of connecting and disconnecting an engine and a power transmission system, a clutch actuator for driving the friction clutch by a fluid pressure supplied from a fluid pressure source, and an actual stroke of the friction clutch in a vehicle state. In a clutch control device including feedback control means capable of controlling the operation of the clutch actuator to adjust the actual stroke so as to approach a target stroke of the friction clutch set based on the PID. A PID control coefficient provided by the PID calculation means is set to be different depending on whether the actual stroke is on the connection side or on the release side of the friction clutch with respect to a reference value. The clutch control device. 2. The clutch control device according to claim 1, wherein the reference value is an actual stroke when a ratio of a change in the fluid pressure to a change in the actual stroke changes. 3. A value obtained by the PID calculation means, a value obtained by multiplying a difference between the actual stroke and the target stroke by a first coefficient, and a value obtained by integrating a value obtained by integrating the difference with respect to time by a second coefficient. And the value obtained by differentiating the above difference with respect to time
The PID control coefficient is composed of the first coefficient, the second coefficient, and the third coefficient. When the actual stroke is closer to the friction clutch connection side than the reference value, the values of the first, second, and third coefficients are as follows. The clutch control device according to claim 1, wherein the clutch control device is set to be smaller than the values of the first, second, and third coefficients in the case of.