JPH0311986A - Speed signal detection device of electromagnetic driving device - Google Patents

Abstract

PURPOSE:To increase the degree of accuracy of operations by digitalizing the operations digital by means of the first and the second operation measures. CONSTITUTION:A speed signal detection device of a magnetic driving device is constituted of the first operation measure 13 performing operations of a fixed time voltage of a driving coil 11 thereof and the second operation measure 14 seeking a speed signal. Operations of the fixed time voltage of the driving coil 11 when the driving coil 11 is kept in a state of fixing forcibly are performed by the first operation measure 13 through a driving voltage of the driving coil 11 and voltage of driving current detection resistance 12. Comparative operations between the driving voltage mentioned above and the fixed time voltage are performed to obtain a speed signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speed signal detection device for an electromagnetic drive device such as a servo motor.

[Conventional technology]

Conventionally, a speed No. 13 detection device for an electromagnetic drive device in which the drive coil and the speed detection coil of the electromagnetic drive device are the same is known from Japanese Patent Application Laid-Open No. 59-156139 and the like.

In the speed signal detection device of this electromagnetic drive device, as shown in FIG. 5, a drive current detection resistor 2 is connected in series with the drive coil 1 of the electromagnetic drive device. An R/C integration circuit consisting of a series circuit of a resistor 3 and a capacitor 4 is connected in parallel with the L/R integration circuit. Then, the drive coil 1 is driven by the drive circuit 5 according to the input voltage, and the arithmetic circuit 6 calculates the difference between the output voltage A of the L/R integration circuit and the output voltage B of the R/C integration circuit, and the speed increases. A signal is required.

This speed signal detection device for the electromagnetic drive device is used in a speed control circuit etc. that controls the speed of the electromagnetic drive device, and this speed control circuit etc. controls the speed of the electromagnetic drive device based on the speed signal from the arithmetic circuit 6. I do.

[Problem to be solved by the invention]

In the speed signal detection device for an electromagnetic drive device, the calculation circuit 6 calculates the difference between the output voltage A of the L/R integration circuit and the output voltage B of the R/C integration circuit to obtain the speed signal.
Because the L/R integration circuit does not become a first-order integration system due to eddy current products, hysteresis loss, etc., it becomes a 0.9-order integration system.
When the drive coil of the electromagnetic drive device is forcibly fixed and a drive current is input to the drive coil, the difference between the output voltage A of the L/R integration circuit and the output voltage B of the R/C integration circuit does not become 0. . Therefore, the speed signal from the arithmetic circuit 6 is mixed with the drive signal of the drive coil 1, and the S/N ratio is deteriorated. This deterioration of the S/N of the speed signal means that when the speed signal detection device of this electromagnetic drive device is used in the speed control circuit to control the speed of the electromagnetic drive device, the speed control band becomes narrow. Put it away.

SUMMARY OF THE INVENTION An object of the present invention is to provide a speed signal detection device for an electromagnetic drive device that can improve the above-mentioned drawbacks and obtain a speed signal with a high S/N ratio.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a drive current detection resistor 12 in a drive coil 11 of an electromagnetic drive device as shown in FIG.
This is a speed signal detection device for an electromagnetic drive device in which the drive coil 11 is forcibly set in a fixed state based on the drive voltage of the drive coil 11 and the voltage of the drive current detection resistor 12. a first calculation means 13 for calculating a fixed special voltage of the drive coil 11; a second calculation means 14 for calculating a speed signal by comparing and calculating the drive voltage of the drive coil 11 and the fixed special voltage of the drive coil 11; It is designed to have the following.

[For production]

The first calculation means 13 calculates the fixed special voltage of the drive coil 11 when the drive coil 11 is forced into a fixed state from the drive voltage of the drive coil 11 and the voltage of the drive current detection resistor 12, and The drive coil 1 is calculated by the calculation means 14.
1 and the fixed special voltage of the drive coil 11 are compared and calculated to obtain a speed signal.

〔Example〕

FIG. 2 shows an example of a speed control circuit for an electromagnetic drive device to which the present invention is applied.

A drive coil 21 of the electromagnetic drive device is driven by a drive circuit 22 consisting of an amplifier, and a drive current detection resistor 23 is connected in series with this drive coil 21. The amplifier 22 drives the drive coil 21 with current by negative feedback of the voltage Vs(t) of the drive current detection resistor 23 via the resistor 24, and has good starting characteristics.

The drive voltage Vi(t) of the amplifier 22 is A/D converted by an analog/digital (A/D) converter 25 and input to a digital signal processor (DSP) 26.
The voltage Vs(t) of the drive current detection resistor 23 is A/D converted by the A/D converter 27 and input to the DSP 26 . The DSP 26 is configured using a microcomputer, and calculates and outputs a speed signal V,(t) from the output voltage of the A/D converter 25 and the output voltage of the A/D converter 27. The speed signal V,(t) from the DSP 26 is D/A converted by a digital/analog (D/A) converter 28 and inputted to the inverting input terminal of the amplifier 22 via a resistor 29. A control signal is input to the non-inverting input terminal of the amplifier 22 via a resistor 30, and the control signal and the D/A converter 2
8 is amplified and applied to the series circuit of the drive coil 2I and the drive current detection resistor 23.

FIG. 3 shows a series of flows of this speed control circuit as a control block diagram.

The drive current l1 (s) flowing through the drive current detection resistor 23 is the value obtained by dividing the voltage V s (s) of the drive current detection resistor 23 by the resistance value Rs of the drive current detection resistor 23, and the self-inductance of the drive coil 21. If the driver is S, the resistance of the drive coil 21 is Re, and the load resistance of the amplifier 22 is RL (=Rc+Rs), then the drive coil 21
The fixed special voltage Vis(s) of the drive coil 2I when it is forcibly fixed is Vis(s) = I 1(s)
RL). Further, the drive current ri(s
) and the moving speed V of the drive coil 21. If the transfer function with (s) is G (s) and the inverse electromotive constant is v, (s) = Ii (s) XG (s) v e (s) ” K e x v o (s) Therefore, the operating special voltage V i (s) of the drive coil 21 when the drive coil 21 moves becomes Vi(s) = Vis(s) −V, (s).

Since Vs(s) and Vi(s) can be measured here,
Once you have figured out the relationship between ll(s) and L and stored it in the memory of the DSP 26, you can find Vi(s) and calculate V , (s)
can be obtained, and a speed equalization signal with a high S/N can be obtained. The DSP 26 detects speed signals based on this principle. Note that Rs is very small, about 1/20 to 30 of Re, and RL constantly changes depending on the heat generated by the electromagnetic coil 21 and the ambient temperature. Therefore, in this example, RL is measured at a certain constant interval (1, ν TM1, for example, every 30 minutes to 1 hour. Also, the self-inductance L of the electromagnetic coil 21 is the drive current l1 (
s) and its frequency. Therefore, DSP26
is L of the drive current detection resistor 23 when the electromagnetic drive device is not operating (when the electromagnetic coil 11 is forcibly set in a fixed state),
Characteristics showing the relationship with ll(s) are actually measured in advance and stored in memory.

FIG. 4 is a flowchart showing the processing flow of the DSP 26.

When the power is turned on, the DSP 26 first clears the timer value Tc in step S1, generates a test voltage V7 in step S2, and inputs it to the amplifier 22 from the control signal input terminal. The voltage (A) to this test 1 is so small that the drive coil 21 does not operate, for example, Vj(t)
Set the value so that it is 5V or less. Next, DSP2
6 is the drive voltage Vi(t) of the amplifier 22 in step S3,
The voltage Vs (+:) of the drive current detection resistor 23 is taken in via the A/D converter 25.27, and RL=
Operation Vi(t)・Rs/Vs(t) (Rs is known)
I do. Next, the DSP 26 outputs the test voltage V in step S5.
, =O, and then the offset adjustment of the drive circuit 22 is performed by setting Vi(t)=O.

Next, in step S6, the DSP 26 checks the output voltage of the A/D converter 27 to determine whether a control signal has been input, and if no control signal has been input, this check is repeated. When a control signal is input, DSP2
6 proceeds to step S7 and sets the drive voltage Vi of the drive circuit 22.
(t), the voltage Vs(t) of the drive current detection resistor 23 is set to A/
The D converters 25 and 27 are inserted, and in step S8, the following calculation is performed: 1(t)=Vs(t)/Rs. Next, in step S9, the DSP 26 stores the relationship between L and ll(t) in its memory, so it calculates L from ll(t) obtained by the above calculation. Next, in step SIO, the DSP 26 calculates V from l, R,, Ij(t) obtained by the above calculation.
js(t) is calculated using the arithmetic expression Vis(s) = I 1(s) X (L S +
RL), and in step Sll, from this Vis(t) and the Vi(t) imported above, V f(t) = V
1(t) −V 1s(t), V g (
Find t). Next, in step 512, the DSP 26 increments the timer value Tc by the timer period Ts, and in step 513, outputs V,(t) obtained by the above calculation as a speed signal.Next, the DSP 26 in step S14
Check the timer value Tc, and if Tc≧TM, return to step S6; if Tc≧TM, step S1
Proceed to step 5 to check whether a control signal has been input. Then, the DSP 26 returns to step S7 if the control signal is input, and returns to step St if the control signal is not input.

Note that the present invention is not limited to the above-mentioned example, and can be used, for example, in a speed control device for a DC motor.

〔Effect of the invention〕

As described above, the present invention provides a speed signal detection device for an electromagnetic drive device in which a drive current detection resistor is connected in series to one drive coil of the electromagnetic drive device.

a first calculation means for calculating a fixed special voltage of the drive coil when the drive coil is forced into a fixed state from the drive voltage of the drive coil and the voltage of the drive current detection resistor; and a second calculation means for calculating a speed signal by comparing the drive voltage of the drive coil with the fixed special voltage of the drive coil, the calculations by the first calculation means and the second calculation means can be digitized (software). ), the calculation accuracy can be improved, and a speed signal with a high S/N ratio can be obtained.

Therefore, when used in a speed control circuit that controls the speed of an electromagnetic drive device, the speed control band can be greatly expanded by increasing the servo gain during speed control, and the transient characteristics can be improved and It becomes possible to increase the control speed. Further, the calculations by the first calculation means and the second calculation means are simple, and furthermore, the calculations by the first calculation means and the second calculation means can be digitized. It becomes possible to reduce the size of the device by incorporating it into an integrated circuit, which facilitates high-mix, low-volume production.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a block diagram showing an example of a speed control circuit of an electromagnetic drive device to which the present invention is applied, and Fig. 3 shows the processing flow of the speed control circuit. FIG. 4 is a flowchart 1 showing a DSP processing flow in the same speed control circuit, and FIG. 5 is a block diagram showing a conventional speed signal detection device for an electromagnetic drive device. 11... Drive coil, 12... Drive current detection resistor,
13...First calculation means, 14...Second calculation means. 14 ni form (chijo)

Claims (1)

[Scope of Claims] A speed signal detection device for an electromagnetic drive device, in which a drive current detection resistor is connected in series to a drive coil of the electromagnetic drive device, the speed signal detection device comprising a drive current detection resistor connected in series to a drive coil of the electromagnetic drive device, wherein a first calculation means for calculating a fixed voltage of the drive coil when the drive coil is forcibly set in a fixed state; A speed signal detection device for an electromagnetic drive device, characterized in that it comprises a second calculation means for calculating a signal.