JPH0341178Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention superimposes an AC component for dithering on a DC component operation command signal corresponding to the amount of operation of the operating section, thereby causing a solenoid valve to undergo minute vibrations. The present invention relates to a control device for a solenoid valve that is controlled while being controlled.

[Prior Art] In recent years, methods for controlling hydraulic pressure using electrical signals have come into widespread use. For example, in aerial work vehicles, hydraulic excavators, hydraulic bulldozers, etc., there is a method of remotely controlling the hydraulic output by converting the operation amount of a control lever on the driver's seat into an electrical signal and operating a proportional solenoid valve.

Conventionally, as a control method of this type, there is a method in which a plurality of solenoid valves are proportionally controlled by a single joystick. Therefore, the conventional example will be explained with reference to FIGS. 6 to 9. In the figure, reference numeral 1 denotes a joystick, and by operating one lever 1a in the vertical and horizontal directions, a built-in variable resistor is varied and converted into an electrical signal.
In this example, by operating the lever 1a in the vertical direction in FIG. 6, a voltage E corresponding to the amount of operation is output. Its output voltage E
When the lever 1a is in the neutral position, the output voltage E of the variable resistor is V0 (=1/2V1) (see Fig. 7). When the lever 1a is tilted in one direction, the output voltage E changes from V0 to "0" according to the amount of tilt, and the first proportional solenoid valve (A valve) changes according to the characteristics of the A curve. Outputs the control current. Valve A operates in accordance with this control current, and the hydraulic output from the valve increases. Also, when lever 1a is tilted in the other direction,
The output voltage E changes from V0 to V1 in accordance with the amount of inclination, and the control current of the second proportional solenoid valve (B valve) is output in accordance with the characteristics of the B curve. Depending on this control current, B
The valve operates and the hydraulic output from the valve increases.

The A and B valves have characteristics as shown in FIG. 8 as proportional solenoid valves, and operate according to a control current to output oil pressure proportional to the control current. For example, when the A valve is used as an output control valve for a hydraulic motor for advancing a controlled object, the forward speed can be controlled in accordance with the operation of the lever 1a. Further, for example, when the B valve is used as an output control valve for a hydraulic motor for reversing the object to be controlled, the reversing speed can be controlled in accordance with the operation of the lever 1a.

By the way, such control of A and B valves is as follows:
In order to eliminate the effect of static friction of the solenoid, the eighth
It is necessary to dither by superimposing the AC component on the DC component as shown in the figure. The AC component for the dither is shown in FIG.

A control device that controls the A and B valves while slightly vibrating the solenoid using such a dither is specifically constructed as shown in FIG. Reference numeral 2 denotes a disconnection detection circuit, which detects disconnection of the variable resistor in the joystick 1 and cuts the output when there is an abnormality. 3 is A/
It is a B valve switching circuit, and the output voltage E is A and B.
This is to determine which control range of the valve is in place. 4 is a check circuit at the initial stage of power-on, which cuts the output while the output voltage E is in an unstable state when the power is turned on.
5 is an absolute value circuit which determines the absolute value of the output voltage E by setting the voltage V0 to "0". Therefore, in this absolute value circuit 5, the output voltage E is V0
It outputs a voltage that increases as it increases in the positive and negative directions. 6 is an oscillation/amplitude control circuit; the oscillation circuit determines the dither frequency, and the amplitude control circuit determines the ripple width. Reference numeral 7 is an output circuit which adds an alternating current component to a direct current component and amplifies the result. The A valve 8 and the B valve 9 are operated by the output current of the output circuit 7.

[Problems to be solved by the invention] The conventional control device described above has the following problems.

The circuit configuration requires many analog ICs such as OPAMPs and comparators, as well as many resistors for setting discrimination values, making the configuration complex.

As specifications change, the circuit configuration must be changed each time.

As the number of external commands from controllers and the like increases, the number of circuits must be increased.

In order to adjust the frequency, amplitude, etc., adjustment means such as a variable resistor is specially required.

This invention solves such problems.

[Means for solving the problem] The solenoid valve control device of this invention superimposes an alternating current component for dithering on a direct current component operation command signal corresponding to the amount of operation of the operating section, and controls the solenoid valve. A control device for a solenoid valve that performs proportional control while subjecting to minute vibrations includes a first storage section that stores a conversion pattern for converting the operation amount of the operating section into a direct current component operation command signal, and an alternating current signal for dithering. The present invention is characterized by comprising: a second storage section that stores generation patterns of the minutes; and a calculation section that calculates a control signal for the electromagnetic valve based on the storage patterns of the first and second storage sections.

[Function] The solenoid valve control device of this invention stores a conversion pattern for converting the operating amount of the operating section into a DC component operation command signal and an AC component generation pattern for dithering. After reading out those patterns, the solenoid valves are controlled according to those patterns.

[Example] Hereinafter, an example of this invention will be shown in Figures 1 to 5.
This will be explained based on the diagram. Note that the same parts as those in the conventional example described above are given the same reference numerals, and the explanation thereof will be omitted.

In Figure 1, 11 is a one-chip CPU;
2 is a ROM, and 13 is a DC power supply. CPU11
is the input voltage E from the joystick 1,
Based on the read data from ROM12,
Control currents for the A and B valves 8 and 9 are output. Its function will be described later along with its operation.
The ROM 12 includes a first storage section that stores patterns as shown in FIG. 2, and a second storage section that stores patterns as shown by solid lines in FIG.

The former pattern shown in FIG. 2 is similar to the above-mentioned pattern shown in FIG.
This is a conversion pattern for converting the manipulated variable a into a DC component operation command signal. That is, when the lever 1a of the joystick 1 is tilted in one direction, the output voltage E changes from V0 to "0" according to the amount of tilt, and the output voltage E changes from V0 to "0" according to the characteristics of the A curve. Control current of solenoid valve (A valve)
It means the relationship of outputting IP. Furthermore, when the lever 1a is tilted in the other direction, the output voltage E changes from V0 to V1 according to the amount of tilt, and the second proportional solenoid valve (B valve) changes according to the characteristics of the B curve. ) means that the control current IP is output. On the other hand, the latter pattern indicated by the solid line in FIG. 3 is a generation pattern for an AC component for dithering, similar to the pattern shown in FIG. It also remembers t and amplitude ΔI.

The CPU 11 includes a disconnection detection section for detecting disconnection of the variable resistor in the joystick 1 and a switching section for switching between the A/B valves, as in the conventional example described above.

Further, the CPU 11 reads the conversion pattern shown in FIG. 2 and the generation pattern shown in FIG. 3 from the first and second storage sections through a reading section (not shown).
The voltage E from the joystick 1 is input to a converter (not shown), and this converter converts the voltage E into the value of the DC component current IP of the operation command based on the conversion pattern shown in FIG. The current IP is input to a current waveform control section (not shown), and this current waveform control section increases or decreases the generation pattern shown in FIG. 3 according to the value of the current IP. That is, when the current IP is large, the generation pattern is slid upward, and when the current IP is small, the generation pattern is slid downward.

The CPU 11 follows the pattern formed in this way (hereinafter referred to as "command pattern").
Outputs control currents for A and B valves 8 and 9. At that time, patterns with a level slightly higher or lower than the command pattern are set, and the current is controlled between the respective patterns. FIG. 4 shows an example in which a pattern with a slightly higher level than the command pattern is set, and the level is less than 1/10 of ΔI. In the figure, P1 is a command pattern, and the current I is controlled between this command pattern P1 and a pattern P2 having a slightly higher level. That is, first, the value of the control current on each pattern P1, P2 and the feedback value of the control current to the A valve 8 or the B valve 9 are compared in a comparing section (not shown). In order to input a feedback current, a current detection resistor 14 is connected to the A and B valves 8 and 9. Further, the comparison timing in the comparison section is set, for example, at intervals of about 10 times the dither frequency. As a result of this comparison, when the feedback control current I is equal to or higher than pattern P2, the output is turned OFF, and when the feedback control current I is smaller than pattern P1, the output is turned OFF. As a result, the control current I
As shown by the solid line in FIG. 4, the patterns P1,
It changes so as to draw a predetermined hysteresis curve during P2.

The operation of the CPU 11 is summarized in FIG.

In addition, when adding the joystick 1, it is sufficient to add only the part surrounded by the imaginary line in FIG. This is because the CPU 11 generally has sufficient margin for both input and output.

[Effects of the invention] As explained above, the solenoid valve control device of this invention has a conversion pan for converting the operation amount of the operating section into a DC component operation command signal, and an AC component generation for dithering. Since the configuration is such that patterns are stored, read out, and then the solenoid valve is controlled according to the patterns, the following effects are achieved.

No adjustment is required and the accuracy is high.

It is possible to provide an inexpensive, high-quality control device with a small number of parts.

It is possible to respond to changes in specifications without designing a new circuit.

[Brief explanation of the drawing]

Figures 1 to 5 are diagrams for explaining one embodiment of this invention, in which Figure 1 is a schematic configuration diagram, Figure 2 is an explanatory diagram of a conversion pattern, and Figure 3 is an AC for dithering. FIG. 4 is an explanatory diagram of the control current, and FIG. 5 is a flowchart for explaining the operation. Fig. 6 is a schematic configuration diagram of the conventional example, Fig. 7 is an explanatory diagram of the conversion pattern, and Fig. 8 is an explanatory diagram of the conversion pattern.
The figure is an explanatory diagram of the operating characteristics of the proportional solenoid valve, and FIG. 9 is an explanatory diagram of the dither. 1... Joystick (operation section), 8, 9...
Solenoid valve, 11...CPU, 12...ROM, 13...
…power supply.

Claims (1)

[Scope of Claim for Utility Model Registration] A control device for a solenoid valve that superimposes an AC component for dithering on a DC component operation command signal corresponding to the amount of operation of an operating section, and performs proportional control while slightly vibrating the solenoid valve. , a first storage unit that stores a conversion pattern for converting the operation amount of the operation unit into a DC component operation command signal, and a second storage unit that stores an AC component generation pattern for dithering. A control device for a solenoid valve, comprising: a storage section; and a calculation section that obtains a control signal for the solenoid valve based on the storage patterns in the first and second storage sections.