JP2014105805A - Solenoid control device and solenoid control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems found in a dither control used for a countermeasure against a hydraulic pressure-current hysteresis of a linear solenoid in which amplitude and frequency of exclusive dither signal should be selected and set for every linear solenoid in order to absorb variation when the control is carried out with the amplitude and frequency of the dither signal being fixed not only due to no addition of appropriate dither signal against an expansion of hysteresis caused by long-term deterioration of oil and magnetic material, but also no consideration against variation of an individual linear solenoid.SOLUTION: A linear solenoid control device performs learning a dither amplitude and frequency in response to a difference between an output hydraulic pressure and an indicated hydraulic pressure. The dither amplitude and frequency are held, updated and referenced for every oil temperature and indicated hydraulic pressure, and the dither signal in compliance with the state is always generated.

Description

  The present invention relates to a control apparatus and method for controlling a solenoid by superimposing a dither signal.

  The linear solenoid is an actuator that adjusts the hydraulic pressure by opening and closing a valve with an electric current as an input. There are various fields of use such as automobiles that perform shift control using hydraulic pressure as a power source. On the other hand, the linear solenoid is known to have hysteresis characteristics between an input current and an output hydraulic pressure. This means that the hydraulic pressure that is the output is not uniquely determined for the current that is the input, and has been regarded as a problem in the field of automatic transmissions that require high controllability for the hydraulic pressure. .

  As a countermeasure against the hysteresis characteristic, dither control in which a minute vibration called dither is applied to a current is widely known. By applying dither to the current, it is possible to slightly vibrate the movable core of the linear solenoid and reduce the hysteresis due to friction.

  Hysteresis varies greatly depending on the oil temperature (low oil temperature increases oil viscosity and linear solenoid friction increases, and vice versa), so the dither amplitude and frequency are set to the oil temperature. It is also widely known that a higher hysteresis reduction effect can be obtained by flexibly changing according to the above. By setting the dither amplitude large and the frequency low at a low oil temperature with a large hysteresis, it is possible to sufficiently vibrate the movable iron core even under a large frictional condition. Also, by setting the dither amplitude small and the frequency high at high oil temperatures with low hysteresis, the hydraulic pressure can be output stably without causing the movable iron core to vibrate more than necessary even under low friction conditions. It becomes possible.

  However, these methods have not yet expanded the hysteresis due to the aging of oil and magnetic materials and absorbed the variation in hysteresis that varies depending on the individual linear solenoid.

  On the other hand, a method of measuring the amount of hysteresis with a sensor and dynamically updating the dither amplitude has been proposed (Patent Document 1). According to this method, it is possible to remove the hysteresis as much as possible by changing the dither amplitude in accordance with the increase or decrease of the hysteresis. In addition, since the dither amplitude can be updated according to the hysteresis, an effect can be expected for temporal fluctuation factors such as aging. However, since this method updates the dither amplitude to a completely new value each time according to the hysteresis, there is a risk that the dither amplitude will fluctuate sharply due to measurement errors and disturbances, and the hydraulic pressure will become unstable. . Furthermore, it is not practical to measure accurate hysteresis by the method described during normal operation. The accurate hysteresis can be measured by applying the described hysteresis measuring method only when a control current for measurement is supplied to the linear solenoid at the time of initialization or the like.

  Although many other methods aimed at reducing the hysteresis of linear solenoids over a long period of time have been proposed, none of them are feasible and practical, and no definitive method has been proposed. there were.

JP 2000-283325 A

  When the control is performed with the amplitude and frequency of the dither signal fixed as in the conventional method, an appropriate dither signal cannot be applied to the expansion of hysteresis due to aging deterioration of oil or magnetic material. Furthermore, the variation of individual linear solenoids is not taken into consideration. To absorb the variation, it is necessary to select and set the amplitude and frequency of a dedicated dither signal for each individual linear solenoid.

An object of the present invention is to increase the hysteresis due to deterioration over time and to vary the hysteresis that varies depending on individual solenoids, and to improve the stability stably.

For example, in the solenoid control apparatus that outputs a control signal to a solenoid installed in the oil passage, the amplitude and frequency of the dither signal to be superimposed on the target oil pressure of the oil passage and the oil temperature of the oil passage Storage means for storing a dither signal having the amplitude and the frequency, and a dither signal generating means for superimposing the dither signal on the control signal, and calculating a differential pressure between the detected oil pressure of the oil passage and the indicated hydraulic pressure of the oil passage Calculating means for updating, updating means for updating the storage of the storage means based on the result of the calculating means, and when the amount of change in the detected oil pressure of the oil passage within a predetermined time exceeds a certain amount, the updating This is achieved by stopping the means.

According to the present invention, it is possible to achieve stability by expanding hysteresis due to deterioration over time and improving variation in hysteresis that varies depending on individual solenoids.

The figure explaining the typical structure of this invention Exemplary control flowchart for implementing the present invention The figure explaining the state in which learning control can be implemented Diagram explaining the effect of dither signal on measured hydraulic pressure Diagram explaining the dither amplitude / frequency table

FIG. 1 shows a typical configuration for carrying out the present invention. The control device 101 performs an operation based on each input and outputs a drive signal for the linear solenoid 103 to the driver circuit 102. The driver circuit 102 amplifies the drive signal from the control device 101, switches the semiconductor element, and supplies a necessary current to the linear solenoid 103. The linear solenoid 103 can control any control object 104 by adjusting the hydraulic pressure. The output oil pressure at the controlled object is detected by the oil pressure sensor 105 and fed back to the control device 101. Each element is connected by a harness 106 as shown in FIG.
In the configuration as described above, learning is performed according to the control flow shown in FIG. First, it is confirmed that both the instruction (target) hydraulic pressure and the measured (detected) hydraulic pressure, which are preconditions for starting learning control, are constantly stable at a constant value (S201). If it is determined that it is stable, the learning control is started, and if it is determined that the hydraulic pressure is in a transitional transition state, the learning control is not performed (stops). In the learning control, first, an absolute difference value between the indicated hydraulic pressure and the measured hydraulic pressure is calculated (S202). Next, it is determined whether the value is equal to or greater than the upper threshold (S203).
If it is equal to or greater than the upper threshold, it is determined that the hysteresis has increased, and the value corresponding to the amplitude increase / decrease width is added to the dither amplitude in the table corresponding to the oil temperature and the command oil pressure at that time (S204), The value corresponding to the frequency increase / decrease width is subtracted (S205).
On the other hand, if the difference absolute value between the command oil pressure and the measured oil pressure is less than or equal to the lower threshold (S206), it is determined that the dither signal is too large, and the amplitude increase / decrease width is determined from the dither amplitude of the table corresponding to the oil temperature and the command oil pressure at that time. The minute value is subtracted (S207), and the value corresponding to the frequency increase / decrease width is added to the dither frequency (S208). If the absolute value of the difference between the command oil pressure and the measured oil pressure is between the upper and lower threshold values, learning is not performed.
Thereafter, it is determined whether the power is turned off by monitoring the power supply voltage of the control device (S209). When it is determined that the power is turned off, the learned dither amplitude / frequency table is recorded in the nonvolatile storage device before the power supply to the control device is cut off (S210), and the series of control is finished. If the power is not turned off, a series of processing is performed again from the beginning.
Here, the important points of the learning control of the present invention will be described more specifically.
First, a state in which “the commanded hydraulic pressure and the measured hydraulic pressure are stable at a constant value”, which is a precondition for starting learning control, will be described with reference to FIG. In the section (a) from time 0 to T1, both the indicated hydraulic pressure and the measured hydraulic pressure are stable at the hydraulic pressure P1, and learning can be performed. However, in the section (b) at time T1 -T2, the command oil pressure changes to P1 -P2 and the command oil pressure immediately stabilizes at P2, but the measured oil pressure gradually changes from P1 to P2. Therefore, in this section (b), there are many hydraulic pressure differences due to responsiveness, so learning cannot be performed. Finally, in the section (c) between time T2 and T3, the measured oil pressure is also stabilized at a constant oil pressure P2, and only a hysteresis component appears in the difference between the command oil pressure and the measured oil pressure. Therefore, learning can be performed in the section (c).
Next, the update of the dither signal will be described with reference to FIG. When a sufficient dither signal cannot be applied to the hysteresis of the linear solenoid, the measured hydraulic pressure converges to a value including a large hydraulic pressure between the command hydraulic pressure and the indicated hydraulic pressure as shown in FIG. In order to suppress the hysteresis, it is necessary to apply a stronger dither signal. For this purpose, it is necessary to update the amplitude large and the frequency low. By setting the update width to be small, it is possible to obtain a filter effect that avoids abrupt update due to disturbance.
When the dither signal can be appropriately applied, the measured hydraulic pressure is an ideal output that substantially matches the indicated hydraulic pressure as shown in FIG. In this case, learning / updating of the dither signal is not performed.
When the dither signal is excessively applied, the measured hydraulic pressure is a vibration output centered on the indicated hydraulic pressure as shown in FIG. Since the dither signal is too powerful, the hysteresis itself is very small, but the dither itself is placed on the hydraulic waveform, causing oil vibration. In order to prevent oil vibration, it is necessary to suppress the output of the dither signal. Therefore, the amplitude is reduced and the frequency is updated higher.
Finally, the dither amplitude / frequency table will be described with reference to FIG. The above update is performed for the dither amplitude and frequency corresponding to the indicated hydraulic pressure and oil temperature at that time. That is, the control device 101 has a two-dimensional table using the command oil pressure and the oil temperature as parameters for each of the dither amplitude and the dither frequency. The update is performed on the dither amplitude Axy and the dither frequency Fxy referred to from the current command oil pressure Pref and the oil temperature Tf. Update is performed by adding / subtracting the dither amplitude increase / decrease width (amplitude correction value) Aid and the dither frequency increase / decrease width (frequency correction value) Fid. As described above, this table is stored in the nonvolatile storage device before the control device is shut off, and the learned value can be referred to and updated even after the power is turned on again.

  According to the present invention, it is possible to reduce current-hydraulic hysteresis due to aging degradation of a linear solenoid, and it is possible to stably output highly accurate hydraulic pressure over a long period of time. In addition, it is possible to reduce the hysteresis characteristic variation which differs for each linear solenoid.

Although the present invention can be used in various fields, it can be said to be a suitable invention particularly in the automobile field that requires high-precision hydraulic control over a long period of time. If the present invention is applied to an automatic transmission such as a continuously variable transmission, it is possible to follow an ideal shift line with higher accuracy, thereby improving fuel efficiency and shifting because a fastening / release element is controlled with higher accuracy. Reduction of shock can also be expected.

101 control device,
102 Linear Solenoid Driver 103 Linear Solenoid 104 Control Object 105 Hydraulic Sensor 106 Harness

Claims (8)

In a solenoid control device that outputs a control signal to a solenoid installed in an oil passage,
Storage means for storing the dither signal amplitude and frequency to be superimposed on the target oil pressure of the oil passage and the oil temperature of the oil passage;
A dither signal generating means for generating a dither signal of the amplitude and the frequency and superimposing the dither signal on the control signal;
A calculating means for calculating a differential pressure between the detected oil pressure of the oil passage and the indicated oil pressure of the oil passage;
Updating means for updating the storage of the storage means based on the result of the computing means;
The solenoid control device characterized in that when the amount of change in the detected oil pressure of the oil passage within a predetermined time exceeds a certain amount, the updating means is stopped.
In claim 1,
If the differential pressure exceeds the upper threshold,
The solenoid control device according to claim 1, wherein the update means adds an amplitude correction value to the amplitude stored in the storage means, and subtracts the frequency correction value from the frequency stored in the storage means.
In claim 1,
If the differential pressure exceeds the lower threshold,
The solenoid control device, wherein the updating means subtracts the amplitude correction value from the amplitude stored in the storage means and subtracts the frequency correction value from the frequency stored in the storage means.
In claim 2 or 3,
A solenoid control device comprising a storage means for storing the update result of the storage means when the power is turned off.
Store the amplitude and frequency of the dither signal to be superimposed on the target oil pressure of the oil passage where the solenoid is installed and the oil temperature of the oil passage,
Generating a dither signal of the stored amplitude and frequency,
Superimposing the dither signal on the control signal to the solenoid;
Detecting the oil pressure in the oil passage;
Calculate the differential pressure between the detected oil pressure and the indicated oil pressure in the oil passage,
Based on the result of the operation, the contents of the memory are updated,
Further, the solenoid control method of stopping the update when the detected amount of change of the hydraulic pressure within a predetermined time exceeds a certain amount.
In claim 5,
If the differential pressure exceeds the upper threshold,
The update is performed by adding an amplitude correction value to the stored amplitude and subtracting the frequency correction value from the stored frequency.
In claim 5,
If the differential pressure exceeds the lower threshold,
The update is performed by subtracting the amplitude correction value from the stored amplitude and adding the frequency correction value to the stored frequency.
In claim 6 or 7,
A solenoid control method, wherein the update result is stored in a nonvolatile memory when the power is turned off.