JPH02277108A - Controller for electromagnetic device having proportional solenoid - Google Patents

Abstract

PURPOSE:To eliminate the adverse influence attended with the temperature rise of a coil by providing a means which integrates the exciting current of the coil synchronously with a pulse signal and a correction coefficient arithmetic means, thereby detecting the exciting current in a sensitive area and obtaining the duty with high efficiency. CONSTITUTION:A reset integration means 105 and a correction coefficient arithmetic means 106 are provided on the controller of an electromagnetic device 104 constituted of a duty arithmetic means 101, a pulse signal production means 102, and an energizing current production means 103. The means 105 integrates the exciting current flowing to the coil of the device 104 synchronously with the pulse signal applied to the means 103. The means 106 calculates a correction coefficient from the ratio between the integrated value of the means 105 and the duty used for the production of the integrated exciting current. Thus the means 101 calculates a new duty from the commanded control target value and the calculated correction coefficient. Consequently, the energizing current is detected in the sensitive area of a control lever which actually actuates the device 104 and the duty is obtained with high efficiency. Thus the adverse influence caused by the temperature rise of the coil can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an electromagnetic device 1 having a proportional solenoid that generates a force according to a supplied current value, such as a device for controlling an electromagnetic proportional valve.

B. Conventional Technology For example, in hydraulic circuits for construction machinery and the like, electromagnetic proportional valves 4 are often used to control oil pressure and oil volume.

The control amount (hydraulic pressure and oil amount) of the electromagnetic proportional valve changes approximately in proportion to the excitation current I of the coil, as shown in the characteristic curve of FIG.

Conventionally, when controlling such an electromagnetic proportional valve 4,
A control device with a circuit configuration as shown in FIG. 9 was used.

That is, the controller 1 composed of a microprocessor (MCU) outputs a digital signal corresponding to a control target value. This digital signal is converted into an analog voltage signal by the DA converter 2.

This analog voltage signal is converted into an analog current signal by a voltage/current converter (VI converter) 3, and the analog current signal is applied to the coil of the electromagnetic proportional valve 4 to excite it.

Here, the voltage/current converter 3 is provided with a dither function, and a high frequency current of 200 to 600 lines is applied to the electromagnetic proportional valve 4.
The coil current is superimposed on the coil current in a range of 10 to 20% of the rated current to reduce the hysteresis of the electromagnetic proportional valve 4.

However, since this configuration uses the DA converter 2 and the voltage/current converter 3 having a dither function, there is a problem that the device becomes expensive.

Therefore, a control device having the configuration shown in FIG. 10 is known as a device for controlling the electromagnetic proportional valve 4 without using expensive circuit components such as a voltage/current converter.

In FIG. 10, 1 is a controller composed of a microprocessor, 5 is an input/output control section composed of a digital output section 5a and an AD conversion section 5b, and 6 is an excitation current that flows through the coil of the electromagnetic proportional valve 4. drive transistor to form;
7 is a flywheel diode.

The controller 1 provides the digital output section 5a with a duty value corresponding to a target value of the excitation current flowing through the coil of the electromagnetic proportional valve 4. The digital output section 5a inputs to the drive transistor 6 a pulse that remains at a high level only for a period corresponding to its duty. As a result, the coil of the electromagnetic proportional valve 4 is energized for a period corresponding to the duty. At this time, the excitation current flowing through the coil has a sawtooth shape due to the inductance component of the coil itself and the action of the flywheel diode 7, and is fed back to the power supply voltage side. The average current value is proportional to the power supply voltage and the duty of the coil current. Therefore, the power supply voltage of the coil is read into the controller 1 via the AD conversion section 5b, and the duty value given to the digital output section 5a is corrected according to the value of the read power supply voltage. This sets the excitation current to its target value.

Therefore, the configuration of FIG. 10 does not require a voltage/current converter and is less expensive than the configuration of FIG. 9. Furthermore, since the actual excitation voltage is detected and fed back, and the duty is corrected so as to approach the control target excitation current, accuracy is improved compared to the apparatus shown in FIG. 6.

However, in the above configuration, the duty is determined from the input groove control target value on the premise of the DC resistance component of the coil in a certain standard state, so the following problem occurs.

When the temperature of the coil increases due to a prolonged energization time or an increase in oil temperature, the direct current resistance of the coil increases accordingly. As a result, even if the control target value is the same, the excitation current is insufficient and the required control amount cannot be obtained.

As a solution to these problems, the
A control device for an electromagnetic device disclosed in Japanese Patent No. 444 is known.

This control device operates as follows.

In the dead band of the control lever, a constant command signal that does not activate the actuator is output, and the excitation current of the coil at this time is amplified by the resistor connected in series with the coil and the potential difference between the ends of the resistor. a differential amplifier,
Detection is performed in combination with a smoothing filter that averages the output of the differential amplifier. That is, the excitation current is detected by sampling the output of the smoothing filter at a predetermined timing. Then, a duty conversion coefficient (correction value) is determined based on the detected excitation current, and a new duty is determined from the control target value output in the sensitive band of the operating lever and the determined duty conversion coefficient.

Problem to be Solved by the C0 Invention However, the control device disclosed in the above publication detects the excitation current that flows due to the operation of the control lever within the dead band, calculates the duty conversion coefficient based on this, and calculates the new duty. Effective correction cannot be made in the sensitive range of the operating lever.In particular, the temperature change in the coil becomes faster and larger as the excitation current increases, so correction is not particularly effective when the operating lever is operated at a full stroke.

In addition, although the pulsations of the excitation current are smoothed by a smoothing filter, the period of the PWM pulse signal due to pulse width modulation drive is usually about 50 to 80Hz, and the time constant of the coil is very large. There is a problem in that a large error may appear in the duty correction amount depending on the timing of sampling without sufficient smoothing.

A technical object of the present invention is to detect the excitation current in the sensitive band, accurately determine the duty, and eliminate the adverse effects associated with the temperature rise of the coil.

09 Means for Solving the Problems To explain with reference to FIGS. 1(a) to 1(Q) which are diagrams corresponding to claims, the present invention comprises a duty calculating means 101 which calculates a duty based on a commanded control target value; It has a proportional solenoid comprising a pulse signal forming means 102 that forms a pulse signal of a calculated duty, and an exciting current forming means 103 that forms an exciting current that energizes the coil of the electromagnetic device 104 according to the formed pulse signal. Applicable to control devices for electromagnetic devices.

The above technical problem is solved by the following configuration.

The invention of claim 1 provides an integrating means 10 for integrating the excitation current of the coil in synchronization with a pulse signal, as shown in FIG. 1(a).
5, and the duty is calculated by the duty calculating means 101 from the commanded control target value and the integral value output by the integrating means 105.

The invention of claim 2 provides an integrating means 1 for integrating the excitation current of the coil in synchronization with a pulse signal, as shown in FIG. 1(b).
05, and a correction coefficient calculating means 106 for calculating a correction coefficient from the ratio of the integral value of the integrating means 105 and the duty provided for forming the integrated excitation current. The duty calculation means 101 is configured to calculate the duty from the value and the calculated correction coefficient.

According to the third aspect of the invention, the duty calculating means 101 calculates the duty based on the deviation between the integral value and the control target value.

Furthermore, according to a fourth aspect of the invention, the integrating means 105 is constituted by an analog integrating circuit.

In the invention of claim 5, as shown in FIG. 1(c), the integrating means 105 is replaced by a current-frequency converting means 10 which generates a pulse train of a frequency corresponding to the excitation current of the coil.
5A, and a counting means 105B that counts this pulse train and is reset in synchronization with the pulse signal, and a duty calculating means 101 calculates the duty from the commanded control target value and the counted value of the counting means. Configure it as follows.

When an excitation current flows through the coil of the electromagnetic device 104, the control amount of the electromagnetic device 104 is controlled accordingly. The excitation current flowing through the coil is integrated by the integrating means 105 in synchronization with the pulse signal applied to the excitation current forming means 103.

The duty calculation means 101 calculates a new duty from the commanded control target value and this integral value. Therefore, an exciting current corresponding to the duty is applied to the coil.

In the second aspect, the correction coefficient is determined from the ratio of the integral value to the duty provided for forming the integrated excitation current. In claim 3, the duty calculating means 101 calculates a new duty from the correction coefficient and the commanded elbow control target value, and the duty is determined from the deviation between the integral value and the control target value.

In a fifth aspect of the present invention, the excitation current is converted into a frequency pulse train according to its magnitude and counted in synchronization with the pulse signal. The duty is determined from this count value and the control target value.

When a new duty is calculated in this way, the duty can be corrected with high precision using the excitation current in the sensitive band of the operating lever. Furthermore, since the excitation current is integrated in synchronization with the pulse signal, the duty can be finely corrected and errors can be reduced.

F. Embodiment 1 First Embodiment FIG. 2 is a block diagram showing a first embodiment in which a control device according to the present invention is used to control an electromagnetic proportional valve.

Reference numeral 11 denotes a controller composed of a microprocessor or the like, and when a control target value commanded from an operating lever or the like is input, it outputs a digital signal (hereinafter simply referred to as duty D) indicating a corresponding duty. . 1
4 is an electromagnetic proportional valve that is driven according to the operation of the operating lever to control oil pressure and oil amount; 15 is a digital output section 15a and A
This is an input/output control section composed of a D conversion section 15b. The digital output section 15a includes a counter for counting the built-in clock signal and a counter for determining one period t of the pulse width modulation drive signal (hereinafter referred to as PWM pulse signal) shown in FIG. 3(b). It has a register that stores a count value. The count value of the counter increases as shown in (a) in FIG. 3(a) in response to the sequential input of the built-in clock signal, and is reset when it matches the value stored in the register shown in (c). The digital output section 15a is also.

It has a register that holds the duty ratio given from the controller 11, and is indicated by the broken line (b) in Fig. 3 (,).
When a duty D as shown in Fig. 3 is given, the period shown in Fig. 3 (
A low level PWM pulse signal as shown in b) is output. In an initialized state, such as immediately after the power is turned on with the operating lever in the neutral position, D=O, and a low-level PWM pulse signal is not output.

Further, 16 is a drive transistor that is turned on at the low level of the PWM pulse signal and supplies a coil excitation current to the coil of the electromagnetic proportional valve 14, 17 is a flywheel diode,
18 is a resistor that is connected in series with the electromagnetic proportional valve 14 and converts the current flowing through the coil into voltage; and 19 is an integrating circuit that integrates the voltage generated in the resistor 18.

Here, when the duty D is output from the controller 11, the digital output section 15a outputs a low level pulse to the driving transistor 1 for a period corresponding to this duty D.
Enter 6. Further, the digital output section 15a outputs the controller 11 at the start timing of each cycle of the PWM pulse signal.
Outputs an interrupt request to. Further, the digital output section 15a outputs the integrator circuit 1 at every other cycle of the PWM pulse signal.
In order to reset the integral value of 9, a high level reset signal is output.

On the other hand, in response to the interrupt request, the controller 11 reads the integrated value of the integrating circuit 19 via the AD converter 15b, and calculates the duty to be output next.
The excitation current flowing through the coil during the period when the reset signal from the digital output section 15a is at a low level is converted into a voltage by the resistor 18 and integrated.

The operation related to the above configuration is shown in the time chart in Figure 3 and in Figure 4.
This will be explained with reference to the flowchart shown in the figure.

First, when the device is powered on, the controller 11 executes the initialization process shown in FIG. 4(a). That is, the controller 11 causes the digital output section 15a to output a high-level reset signal to initialize (reset) the integral value of the integrating circuit 19 (step 51).6 Next,
The duty conversion coefficient K, which is a coefficient for calculating the duty, is initialized to the standard value Ko, and the control target values commanded from the control lever and the values of the duty ' are initialized to I=O and D=O, respectively. (step S2), and then waits for an interrupt request to be input from the digital output section 15a (step S3).

In this initialized state, the duty D is 0 and no low-level PWM pulse signal is output, so no excitation current flows through the coil and the electromagnetic proportional valve 14 is not driven.

Note that the standard value Ko is a value when the coil resistance and power supply voltage are set to a certain standard state.

In this initialized state, when an interrupt request is input to the controller 11 every cycle, the controller 11
executes the interrupt processing shown in FIG. 4(b).

In this interrupt processing, first, it is determined whether the reset signal output from the digital output unit 15a is at a high level or a low level, and when it is at a high level, the reset signal is set at a low level in order to perform an integral operation in the current cycle. (Step S
ll, 20), when the reset signal is at low level, the integration operation is performed in the previous cycle, so the integral value Ii of the integration circuit 1''9 is read through the AD conversion section 15b (step 512), and then reset. Switch the signal to high level,
Resetting the integral value Ii of the integrating circuit 19 (step 5
13).

Next, the duty conversion coefficient is calculated, but since D=O or l1=O in the initialized state or the state where the drive of the electromagnetic proportional valve 14 is stopped, it is set to =Ko (step S14).゜15.19) This duty conversion coefficient K is multiplied by the control target value I to calculate the duty D for the next cycle (step 517). If the operating lever is not operated, the control target value is 0. Tame D=O
Therefore, the exciting current of the electromagnetic proportional valve 14 does not flow.

Thereafter, the value of the control target value I given by the operation of the control lever is read (step 818), and the process waits until the next interrupt request is input.

Now, step 818 of the first interrupt processing after initialization
Assuming that a control target value of I=I (t,) is commanded from the operating lever, in the second interrupt process,
If the reset signal in the previous cycle is at a high level, step S17 is performed after step 520 is executed.

The calculation D=Ko·I (t□) is performed, and the duty D of the third period is determined. As a result, the electromagnetic proportional valve 14 is driven only during the period in which the PWM pulse signal is at a low level corresponding to the duty D at this time. Then, assuming that the control target value I=I (t,) is read in the last step 81B of the second interrupt processing, the processing of steps 811 to S16 is executed in the third interrupt processing, step s
At 16.

The calculation K=D/Ii is executed, and the duty conversion coefficient K is determined from the ratio of the integral value Ii of the excitation current flowing in the third cycle and its duty D. Then, in the first step 817, this duty conversion coefficient K is multiplied by the next control target value I (t2) to obtain the duty D of the fourth cycle.

As a result of such control, an excitation lt flow having a waveform shape as shown in FIG. 3(d) flows through the coil of the electromagnetic proportional valve 14. Then, the integrating circuit 19 integrates the excitation current in synchronization with the PWM pulse signal, and outputs an integrated value Ii as shown in FIG. 3(e).

In this way, the ratio (duty conversion coefficient) of the actual value (Ii) of the excitation current to an arbitrary duty D is calculated, and the duty of the next output PWM pulse signal is calculated based on the ratio. Even if there is a temperature change in the coil, the excitation current can be brought close to the control target value with high precision. Also, the actual value of the excitation current (Ii)
is fed back every other cycle of the pulse width modulation drive, so the duty conversion coefficient K is changed in accordance with the momentary changes in the excitation current with high precision. Therefore, the error in the duty correction amount is also extremely small.

In the configuration of the above embodiment, the controller 11 constitutes a duty calculating means, the digital output section 15a constitutes a pulse signal forming means, the driving transistor 16 constitutes an excitation current forming means, and the integrating circuit 19 constitutes an integrating means.

In the above embodiment, the voltage across the resistor 18 generated by the excitation current is integrated every other period of the PWM pulse signal, but the duty conversion coefficient K with the required accuracy
The number of cycles may be two or more as long as it is within the range in which the following can be obtained.

Second Embodiment FIG. 5 is a block diagram showing a second embodiment in which a control device according to the present invention is used to control an electromagnetic proportional valve. In this embodiment, the integrating circuit of the first embodiment is constructed using a digital circuit. Hereinafter, parts similar to those in FIG. 2 will be designated by the same reference numerals, and the explanation will focus on the differences.

21 is a voltage-frequency converter that generates a pulse train with a frequency proportional to the voltage generated across the resistor 18; 22 is a counter that integrates and counts the number of pulses in the pulse train.

Here, when the duty D is output from the controller 11, the digital output section 158' inputs a low level pulse to the drive transistor 16 for a period corresponding to this duty D. Moreover, the digital output section 15a is a PWM
Controller 1 at the start timing of each cycle of the pulse signal.
Outputs an interrupt request for 1.

On the other hand, in response to the interrupt request, the controller 11 reads the count value of the counter 22 via the digital input section 15b, and then outputs a reset signal for resetting the counter 22 via the digital output section 15a. Furthermore, the duty to be output next is calculated based on the obtained count value and control command input.

The operation related to the above configuration is shown in the time chart in Figure 3 and in Figure 4.
This will be explained with reference to the flowcharts in FIG. 6(a) and FIG.

First, when the device is powered on, the controller 11 executes the initialization process shown in FIG. 4(a). That is,
The controller 11 outputs a pulsed reset signal to the digital output section 15a.

The reset signal is a pulse-like signal with a sufficiently short pulse width relative to the period of the PWM pulse signal, and the counter 22 is reset (O) at the rising edge of the reset signal.
(cleared) (step 51) 6 Next, step S
2, as above, the duty conversion coefficient = standard value Ko,
Control target value I=O.

Initialization of duty D=O is performed (step S2)
Thereafter, it waits for an interrupt request to be input from the digital output unit 15a (step s3).

In this initialized state, if an interrupt request is input to the controller 11 every cycle, the controller 11
Execute the interrupt processing shown in the figure.

In this interrupt processing, in step 512A, the counter count value IC is read through the digital input section 15b,
Thereafter, a reset signal is output to reset the counter 22 (step 513).

Next, the duty is calculated in step S17 through steps 814 to s16 and S19 similar to those described above. In this embodiment as well, the duty D is determined as the product of the control target value I and the duty conversion coefficient, as described above. Therefore, a coefficient representing the degree of excess or deficiency between the commanded current value and the actually flowing current value is selected as the duty conversion coefficient.

In 22, the duty D is used as a representative value of the commanded current value, the integrated count value Ic of the counter 22 is used as a representative value of the actual current value, and the duty conversion coefficient is K=D/Ic. is calculated in step 516A, and D is calculated in step S17.
A new duty D is calculated by = -I and output to the digital output section 15a (step S7), and
Read control target value I in preparation for the next cycle (step 31
8) Return from interrupt processing.

Through such control, an exciting current having a waveform as shown in FIG. 3(d) flows through the coil of the electromagnetic proportional valve 14, as in the previous embodiment. The excitation current is converted into a voltage by a resistor 18, and further converted by a voltage-frequency converter 21 into a pulse train having a high frequency when the current value is high and a low frequency when the current value is low. Therefore, the count value of the counter 22 indicates the integrated value of the current since it was reset by the reset signal.

The average value of the excitation current is Ic/l, but since one period t of the PWM pulse signal is a constant value, the average value and Ic are in a proportional relationship, and the proportionality constant should be included in the duty conversion coefficient. For example, the integrated count value Ic can be treated as the average value of the excitation current.

In this way, in this embodiment, the ratio (duty conversion coefficient) of the actual @(Ic) of the excitation current to an arbitrary duty D is obtained, and the duty of the PWM pulse signal to be output next is calculated based on the ratio. Even if there is a temperature change in the coil of the electromagnetic proportional valve 14, the excitation current can be brought close to the control target value with high accuracy. Furthermore, since the actual value (Ic) of the excitation current is fed back every cycle of the pulse width modulation drive, the duty conversion coefficient K is changed in accordance with the momentary change in the excitation current with high precision. Therefore, the error in the duty correction amount is also extremely small.

In the configuration of the above embodiment, the controller 11 serves as a duty calculating means, the digital output section 15a serves as a pulse signal forming means, the drive transistor 16 serves as an excitation current forming means, and the resistor 18 and voltage-frequency converter 19 serve as a current-frequency converter. The converting means and the counter 22 constitute counting means, respectively.

-Third Example- The third embodiment will be explained with reference to FIGS. 7(a) and 7(b).

Note that the hardware configuration is the same as that shown in FIG.

When the power is turned on, the initialization process shown in FIG. 7(a) is executed by the controller 11. First, controller 1
1 sends a reset signal to the counter 22 via the digital output section 15a to set the count value to O (step SL).
), then the control target value I and duty D commanded from the operating lever are initialized to I=O and D=O, respectively (step 52A). After this, an interrupt request is received from the input/output control unit 15. is input (step S3).

In this initialized state, every cycle' the controller 11
When an interrupt request is input to the controller 11, the controller 11 executes the interrupt process shown in FIG. 7(b).

In this interrupt processing, first, the count value Ic of the counter 22 and the control target value ■ are read through the input/output control unit 15 (step 5L2B), and then a reset signal is sent to the counter 22 to set the count value to O ( Step 313), the count value Ic is multiplied by the count value Ks to match the control target value I and the calculated level, and is converted into a current If. (deviation from the current) is determined (step 521) 4
The duty D is calculated by adding the product of the deviation DELT found this time and the gain Ki to the duty D output in the previous cycle (
(If DELT is negative, it will be decreased) (step 522), where Ki is the control gain; if it is large, the coordination is good, but it tends to be unstable, and if it is small, it is not stable. However, it tends to lack coordination.

Output the finally calculated duty D (step 8
23), this is done by rewriting the register storing (mouth) shown in FIG. 3(a)'.

In the third embodiment, the duty D is calculated by feeding back the deviation DELT between the control target value given from the operating lever and the actual current value If. The same effects as in the first and second embodiments can be obtained.

Note that although the electromagnetic proportional valve has been described above, the present invention can also be applied to other electromagnetic devices having a proportional solenoid.

G6 As explained in detail in the invention, in the present invention, the excitation current within the sensitive band of the operating lever that actually operates the electromagnetic device such as the electromagnetic proportional valve is integrated, and the control target value commanded from the operating lever etc. is calculated. Since the duty is determined based on the integral value and the integral value is performed in synchronization with the PWM pulse, it is possible to compensate for changes in the excitation current due to increases in the temperature of the coil of the electromagnetic device with high accuracy.

Therefore, for example, in a trajectory control system for a multi-jointed arm that uses feedforward to control the control amount by an electromagnetic proportional valve, the deviation between the actual trajectory and the calculated trajectory will be extremely small, and in a speed control system, the speed deviation will be extremely small. This effect can be obtained. Furthermore, in a system that uses feedback control in combination, the deviation between the feedback amount and the target value is reduced, making it possible to perform stable control.

[Brief explanation of drawings]

FIG. 1 is a complaint correspondence diagram. 2 and 5 are configuration diagrams showing the first and second embodiments of the present invention, FIG. 3 is a time chart for explaining the operation of the embodiment, and FIGS. 4, 6, and 7 The figures are a flowchart showing an overview of the duty correction process in each embodiment, FIG. 8 is a characteristic diagram showing the relationship between the excitation current of the electromagnetic proportional valve and the control amount, and FIG. 9 is a configuration diagram showing an example of a conventional device. FIG. 10 is a configuration diagram showing another example of the conventional device. 11: Controller 14: Solenoid proportional valve 15: Input/output control section 15a: Digital output section 15b: AD
Conversion section 16: Drive transistor 17: Flywheel diode 18: Resistor 19: Integrating circuit 21: Voltage-frequency converter 22: Counting circuit 101: Duty calculating means 102: Pulse signal forming means 103: Excitation current forming means 104: Electromagnetic device 105:
Integrating means 105A: Current-frequency conversion means 105B: Counting means 106: Correction coefficient calculating means

Claims (1)

[Claims] 1) Duty calculating means for calculating a duty based on a commanded control target value, pulse signal forming means for forming a pulse signal of the calculated duty, and an electromagnetic converter according to the formed pulse signal. An apparatus comprising an excitation current forming means for forming an excitation current to be applied to a coil of the apparatus, further comprising an integrating means for integrating the excitation current of the coil in synchronization with the pulse signal, and the duty calculation means is configured to generate a command. 1. A control device for an electromagnetic device having a proportional solenoid, characterized in that a duty is calculated from a control target value that is calculated and an integral value outputted by the integrating means. 2) Duty calculating means for calculating a duty based on the commanded control target value, pulse signal forming means for forming a pulse signal of the calculated duty, and energizing the coil of the electromagnetic device according to the formed pulse signal. An apparatus comprising an excitation current forming means for forming an excitation current, an integrating means for integrating the excitation current of the coil in synchronization with the pulse signal, and an integral value of the integrating means and the integrated excitation current. and a correction coefficient calculating means for calculating a correction coefficient from a ratio with a duty provided for the purpose of calculating the correction coefficient, the duty calculating means calculating a duty from a commanded control target value and a calculated correction coefficient. A control device for an electromagnetic device having a proportional solenoid. 3) Duty calculating means for calculating a duty based on the commanded control target value, pulse signal forming means for forming a pulse signal of the calculated duty, and energizing the coil of the electromagnetic device according to the formed pulse signal. An apparatus comprising an excitation current forming means for forming an excitation current, further comprising an integrating means for integrating the excitation current of the coil in synchronization with the pulse signal, and the duty calculating means is configured to calculate the integral value of the integrating means and the integral value of the integrating means. A control device for an electromagnetic device having a proportional solenoid, characterized in that a duty is calculated according to a deviation from the control target value. 4) A control device for an electromagnetic device having a proportional solenoid according to any one of claims 1 to 3, wherein the integrating means has an analog integrating circuit. 5) The control device according to any one of claims 1 to 3, wherein the integrating means includes current-frequency converting means that generates a pulse train of a frequency corresponding to the excitation current of the coil, and counts this pulse train. and a counting means that is reset in synchronization with the pulse signal, wherein the integral value is a count value.