JPS6022484A - Speed controller for motor - Google Patents

Abstract

PURPOSE:To obtain an accurate speed indicator by obtaining the difference between the speed value which varies at an age and the rotating speed value of a motor for driving an indicating needle, calculating the correction amount signal by difference and the load average of the acceleration, and tracking the motor. CONSTITUTION:Speed value PS which varies at an age of an axle obtained from set speed generating means 1 and a speed value PM of a speed indicator 2 having an indicating needle 2 coupled via an eddy current joint 24 to a motor 3 are inputted to a controller 4, the difference is detected by a detector 403, the acceleration is detected by a detector 404, both are applied to a calculator 405 to obtain a correction amount signal by the load average. The signal is applied through a control amount calculator 406 to the motor 3 to control the motor 3 for the rotating speed of the motor 3 to coincide with the set speed PS. Therefore, the rotating speed of the axle of a vehicle can be accurately indicated by a needle 22, thereby eliminating a meter cable to improve the reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor speed control device, and more particularly to a speed control device that causes the motor speed to follow a speed setting value that changes over time.

Conventionally, in vehicle speedometers, etc., a meter cable is laid between the axle and the meter pointer, and one end of the cable is connected to the axle so that it rotates integrally with the axle, and the other end is connected to the meter pointer via an eddy current joint. The pointers are connected to each other and are configured to operate in accordance with the rotational speed of the axle, that is, the traveling speed of the vehicle. In such a structure, it is necessary to secure a space for installing the meter cable, and fatigue of the cable itself is also a problem.

Therefore, if the rotational speed of the motor can be made to accurately follow a rotating body whose rotational speed changes over time, such as the axle, the speed display pointer should be connected to the motor via an eddy current joint. This makes the rotational speed indicator more compact and reliable.

Furthermore, there is a great need not only for the above-mentioned rotational speed indicator but also for all industrial fields to enable the rotational speed of a motor to accurately follow a speed setting value that changes over time.

SUMMARY OF THE INVENTION In view of these demands, it is an object of the present invention to provide a motor speed control device that allows the motor speed to extremely accurately follow a speed rise setting value that changes over time.

That is, the motor speed control device of the present invention includes a set speed generating means for generating a speed setting value that changes over time, a motor speed detecting means for detecting the rotational speed of the motor, and a motor speed detecting means for detecting the difference between the prescribed speed and the motor speed. A speed difference calculation means for calculating, a motor acceleration calculation means for calculating the amount of change in the motor speed, a correction amount signal is calculated from the weighted average of the speed difference and the motor acceleration rate, and a motor control amount is calculated from the correction amount signal. and motor control means for calculating the signal and outputting the control amount signal to the motor in order to make the rotational speed of the motor match the set speed.

Hereinafter, the configuration and operation of the present invention will be explained with reference to illustrated embodiments.

Fig. 1 shows the overall configuration of a rotational speed indicator using the present invention. In the figure, 1 is a rotational speed detection sensor which is a set speed generating means, and is connected to a rotating body such as an axle of a vehicle (not shown). Permanent magnets 12 having magnetic poles formed at equal intervals at four locations in the circumferential direction are integrally provided on the rotating shaft 11. A reed switch 13 is disposed near the rotating shaft 11, and a contact closes each time the magnetic pole of the permanent magnet 12 passes, generating a pulse signal PS corresponding to the rotational speed of the rotating shaft 11.

2 is a speed display section. The speed display section 2 has a speed display board 2
A display pointer 22 is provided so as to be rotatable along 1, and the end of the rotating shaft of the display pointer 22 is formed into a disk shape and serves as a conductive plate 24a. A disk-shaped permanent magnet 24b is also opposed to the conductive plate 24, and the magnet 24b and the conductive plate 24b constitute an eddy current joint 24. The magnet 24b is held by a holder 25 and connected via a joint 26 to a DC motor 3 for rotational driving.

The magnet 24b has magnetic poles formed at equal intervals at four locations in the circumferential direction, and as the magnet 24 rotates, an eddy current is generated in the conductive plate 24a, and rotational force is transmitted.

On the other hand, a spring 23 for biasing the pointer 22 in the return direction is provided on the rotation axis of the display pointer 22, and the pointer 22 receives the rotational force transmitted in proportion to the rotational speed of the drive motor 3 and the spring 23. It rotates to the angular position where the spring forces of 23 are balanced and the speed is displayed. Therefore, if the speed of the drive motor 3 is controlled to always match the set speed of the rotating shaft 11 of the sensor 1, accurate speed display of the rotating body is possible.

Therefore, a reed switch 27 is provided in the speed display section 2 in proximity to the permanent magnet 24b. reed switch 2
7 is a drive motor 3 whose contacts close each time the magnet 24b passes.
A pulse signal PM is generated according to the rotation speed of the motor.

The above-mentioned rotating shaft speed pulse signal PS and the above-mentioned motor speed pulse signal PM are both input to the control circuit 4, and the control circuit 4 adjusts the rotational speed of the rotating shaft 11 and the driving speed in order to make both pulse signals PS and PM coincide. motor 3
A motor drive signal Tn is output to match the rotational speeds of the two motors.

The control circuit 4 includes waveform shaping circuits 401A, 401B, 2
Multiplier circuits 402A, 402B, speed difference detection circuit 403
, motor acceleration detection circuit 404, correction amount calculation circuit 405
, control amount calculation circuit 406, positive offset generation circuit 407
, negative offset generation circuit 408, motor drive circuit 409
and a timing pulse generation circuit 410 that controls the operation of each of the above circuits.

The speed pulse signals PS and PM are each provided by a waveform shaping circuit 40.
After waveform shaping with 1A and 401b (signals fS, fM)
, a doubling circuit 402A to improve calculation accuracy.
, 2x signal 2f having twice the frequency at 402B
S, 2fM. A speed difference detection circuit 403 takes the difference between the signals 2fS and 2fM and generates a speed difference signal ΔV. The motor acceleration detection circuit 404 calculates the difference between the successively input signals 2fM and generates an acceleration signal α.

The correction amount calculation circuit 405 calculates a correction amount 11 from the speed difference signal ΔV and the acceleration signal α and outputs it, as will be described later. The control amount calculation circuit 406 generates a control amount signal TC based on the correction amount signal 11, and the motor drive circuit 409 applies each offset circuit 407, 408 to the control amount signal TC.
The motor drive signal Tn is output by adding offset signals T+0 and T-0 from the motor drive signal Tn.

The configuration and operation of each circuit described in (1) will be explained below.

FIG. 2 shows a waveform shaping circuit 401A and a doubling circuit 401A.
02A is shown. The waveform shaping circuit 401A includes a switching circuit 401a using a transistor and a NAND gate 401b having a Schmitt trigger function (for example, C
D4093). In the figure, VB is a power supply. The double multiplier circuit 402A is a monostable multivibrator 402a,
402b (for example, CD4047 made by RCA), generates pulse signals a and b synchronized with the rise or fall of the signal fS input from the shaping circuit 401A, and converts these into N
A doubled signal 2fS is obtained by inputting it to the OR gate 402c. Here, Fig. 3 (1), (2), (3)
, (4) show the waveforms of the above-mentioned signals fS, a, b, and 2fS.

Note that the waveform shaping circuit 401B and the doubling circuit 402B
Also has the same configuration as each of the circuits 401A and 402A described above.

FIG. 4 shows a speed difference detection circuit 403. 403a in the diagram
, 403b is a D-type flip-flop (for example, CD4013 manufactured by RCA), 403c, 403d are synchronous differentiators (for example, CD4520 manufactured by RCA), 403e, 403f,
403g is a presettable up/down counter (for example, Texas Instruments SN74LS193)
They are connected to each other in cascade to form a 9-bit up/down counter. 403h, 403i, 403j
is a data latch.

The 2 multiplier signals 2fS and 2fM (see Fig. 5 (1) and (2)) are the timing pulse SC (
While the signals (see FIG. 5(3)) maintain the "1" level, they are input to the D terminals of flip-flops 403a and 403b via gates 403k and 403l, respectively. The above signals 2fS and 2fM are the timing pulse S1 (Fig. 5 (4)
They appear at the Q terminals of flip-flops 403a and 403b as signals c and d (see (5) and (6) in FIG. 5), respectively, at the rising or falling timing of the signal (see FIG. 5).

Differentiators 403c and 403b output pulse signals c and f (FIG. 5 (8), (9)) is output. The above pulse signal c,
f are up/down counters 403e to 403g, respectively.
The signal is input to the UP and DW terminals of the pulse signals e and f, and the difference in the number of pulses between the two pulse signals e and f is calculated here. That is, the counters 403e to 403g are set to 0 except for the most significant bit (Ai terminal of the counter 403g) by the timing pulse CL3' (see (10) in FIG. 12) before the start of counting. Then, the pulse signals e and f inputted during a predetermined count period when the timing pulse SC is at the "1" level are up-counted or down-counted and outputted as an 8-bit pulse difference signal.

The pulse difference signal is applied to the data latches 403h and 4 at the timing of the timing pulse CL2 (see FIG. 12 (6)).
03i. Note that if the number of pulses of the pulse signal f is greater than that of the pulse signal e, the counter 403
The output of the AO terminal of the data latch 403j becomes the "0" level, the pulse difference signal is completely inverted by the exclusive OR (EOR) gate 403m, and the "1" level signal is input to the D1 terminal of the data latch 403j.

Through the above procedure, the data latches 403h to 403j output a speed difference signal ΔV consisting of a 1-bit positive/negative signal vp and an 8-bit absolute value data signal vd. The positive/negative signal vp becomes the "0" level when the signal 2fS>2fM, that is, when the speed difference signal ΔV>0.

FIG. 6 shows the motor acceleration detection circuit 404.

404a, 404b, 404c, 404d, 404 in the figure
e, 404f are presettable up/down counters (
For example, with the RCA CD4029), the counter 404a
404c and counters 404d to 404f are connected in cascade to form a 12-bit up counter and a 12-bit up/down counter, respectively. 404g, 404h, 404i are data latches, 4
04j and 404k are D-type flip-flops.

2 multiplier signal 2 input to the detection circuit 404 during a predetermined count period when the timing pulse SC is at the "1" level.
While fM is counted by the counters 404a to 404c, it is also input to the counters 404d404f, where the counters 404a to 404 are counted during the immediately preceding counting period.
The difference from the doubled signal 2fM counted at c is calculated.

That is, before the count starts, the count value of the doubling signal 2fM counted by the counters 404a to 404c during the immediately preceding count period is transferred to the counters 404d to 404d at the timing of the timing pulse CL3 (see (7) in FIG. 12).
404f, and C is preset during the current count cycle.
The preset value is counted down by the doubling signal 2fM input to the p terminal.

Incidentally, the counters 404d to 404f initially function as down counters, but when the number of input pulses of the doubling signal 2rM during the count period becomes larger than the preset value, the CO terminal output of the counter 404f becomes the "0" r level, and this At the pulse timing of the doubling signal 2fM that follows, the Q terminal output of the flip-flop 404j is inverted and becomes the "1" level.
~404f counts the remaining input pulses as an up counter. In this way, the counters 404d to 4
From 04f onwards, the double signal 2f during the previous count period
The pulse difference between M and that during the current count period is output, and this pulse difference is stored in the data latches 404g to 404i at the timing of the timing pulse CL2 and is output as 8-bit absolute value data αd.

On the other hand, the flip-flop 404k has a timing pulse C
The D terminal input is output to the Q terminal and the Q terminal at the timing of L3. That is, when the pulse difference calculated by the counters 404d to 404f is positive, that is, when the motor acceleration is negative, the signal α-, which is the Q terminal output, is at the "0" level, and the signal α+1, which is the Q terminal output, is at the "1" level. ” level. Conversely, when the pulse difference is negative, that is, when the motor acceleration is positive, the signal α- is at the "1" level and the signal α+ is at the "0" level.

Note that, before the count starts, the counters 404a to 404c are preset to 0 at the timing of the timing pulse CL5 (see FIG. 12 (9)). In addition, the flip-flop 404j receives a timing pulse CL4 (FIG. 12 (8)
(see).

Through the above procedure, the motor acceleration detection circuit 404 outputs an acceleration signal α consisting of 2-bit positive/negative signals α+, α- and 8-bit absolute value data αd. in this case,
As described above, when the acceleration signal α>0, the signal α+ becomes the “0” level, and when the acceleration signal α<0, the signal α+ becomes the “1” level.

The correction amount calculation circuit 405 is not shown in FIG. 405a in the figure
, 405b are presettable down counters (for example, R
CD40103) manufactured by CA Corporation.

The counters 405a and 405b each have acceleration absolute value data α at the timing of the timing pulse CL5.
d and absolute value data vd of the speed difference are preset. The C0 terminal output of each counter 405a, 405b becomes "1" level during the above presetting, and the preset value is C0.
When it is counted down by the pulse input from the K terminal and reaches 0, it becomes the "0" level. Also, the counting operation is Ci
This is performed only when the terminal is at the "0" level.

Therefore, the absolute value data αd preset in the counter 405a is counted down by the clock pulse Sα (see FIG. 12 (1)), and a pulse having a pulse length determined by the above data αd and the clock pulse Sα is output from the CO terminal of the counter 405a. A signal g is output. Further, the absolute value data vd preset in the counter 405b is counted down by the clock pulse SV (see FIG. 12 (2)), and a pulse having a pulse length determined by the above data vd and the clock pulse SV is output from the CO terminal of the counter 405b. A signal h is output.

The pulse signals g and h are added or subtracted according to the positive/negative of the new speed difference ΔV and the positive/negative of the acceleration signal α, and are outputted as the acceleration correction amount signal HA or deceleration correction amount signal HB which constitute the correction amount signal H.

For example, when the speed difference signal ΔV>0 and the acceleration signal α>0,
The positive and negative signals vp are at the "0" level, and the positive and negative signals α+, α
- are "0" level and "1" level, respectively. In this state, the output of the EOR gate 405c is at 0 level, and both the counters 405a and 405b start counting operations using the clock pulses Sα and Sv. Assuming that K1 is a constant determined by the ratio of the pulse periods of the clock pulses Sα and Sv, if K1·vd>αd, the counter 405a finishes counting earlier than the counter 405b, and the pulse signal g that is the output from the CO terminal The level becomes "0". From this point on, the remaining portion of the pulse signal h passes through the EOR gate 405d and the AND gate 405e and is output as the acceleration correction amount signal HA. That is, in this case, the difference between the pulse signals g and h, that is, K1·vd-
αd is output as signal HA. In this way, the calculation circuit 405 calculates the acceleration correction amount signal HA or the deceleration correction amount signal HB as a weighted average of the speed difference ΔV and the motor acceleration α, as shown in the table on the next page. The above example corresponds to the case of m1 in the table. And m1, m2 in the above table
, m3, m4, m5, m6 are each point m on the line M in FIG.
It corresponds to 1 to m6.

Lines M and R in the figure indicate changes over time in the rotational speeds of the motor 3 (see FIG. 1) and the rotating shaft 11, respectively.

FIG. 8 shows the control amount calculation circuit 406. 406a in the diagram
, 406b, and 406c are up/down counters (for example, SN74LS193 manufactured by Texas Instruments), which are connected in cascade to form a 12-bit floating counter. 406d and 406e are presettable down counters (for example, RCA CD40
103), which is also connected in cascade to form a 12-bit down counter.

Correction amount signals HA and HB from the correction amount calculation circuit 405
is input, during this time the AND gate 406f or 40
6g is opened and a clock pulse Sp1 (see FIG. 12 (3)) is input to the counters 406a to 406c. and,
The counters 406A to 406c count up when the signal HA is input, and count down when the signal HB is input.

The outputs of the counters 406a to 406c are preset to the counters 406d and 406e at the timing of the timing pulse Sf (see (12) in FIG. 12). This preset value is counted down by a clock pulse Sp2 (see FIG. 12 (4)) inputted via an AND gate 406h, and a control amount signal Tc having a pulse length proportional to the preset value is output from the CO terminal of the counter 406e.
is output.

Here, if K2 is a constant determined by the ratio of the pulse periods of clock pulses Sp1 and Sp2, then the control amount signal T
C is expressed by the following formula.

TC=TC-1+K2・HA・・・・・・(1) or TC=TC-1−K2・HB・・・・・・(2) Above formula (
In 1) and 2), TC-1 is the previous control amount signal.

Note that in the circuit 406, counters 406a to 4
06c is set to 0 by the reset pulse SR when the power is turned on. The counters 406a to 406c are also A
By closing the ND gates 406i and 406j, counting below 0 and above 4095 is prohibited.

FIG. 9 shows a positive offset circuit 407 and a negative offset circuit 408. In the figure, 407a and 408a are both monostable multivibrators (for example, RCA CD40
47).

The multivibrator 407a receives a timing pulse St(
A positive offset signal T+0 having a predetermined pulse length is output at the falling timing (see FIG. 12 (11)).

Furthermore, the multivibrator 408a outputs a negative offset signal T-0 having a predetermined pulse length at the falling timing of the offset signal T+0.

FIG. 10 shows a motor drive circuit 409. 409 in the diagram
a is a motor drive IC (for example, M5454 manufactured by Mitsubishi Electric)
3L).

The reset pulse SR is at the "1" level except when the power is turned on, and both control signals TC and the new positive offset pulse T+0 are input to the I1 terminal of the driving IC 409a.
The negative offset pulse signal T-0 is input to the I2 terminal.

As a result, a motor drive signal Tn appears between the O1 terminal and the O2 terminal of the drive IC 409a connected to the drive motor 3 (see FIG. 1). This signal Tn has a current of O1 when the above-mentioned signal TC and T+0 are input.
This signal causes current to flow from the terminal to the O2 terminal, and when the above signal T-0 is input, current flows from the O2 terminal to the O1 terminal. The motor 3 is driven in the forward rotation direction against the spring force of the spring 23 (see Figure 1) by the current flowing from the O1 terminal to the O2 terminal, and is driven in the reverse rotation direction by the current flowing from the O2 terminal to the O1 terminal. .

FIG. 11 shows a timing pulse generation circuit 410 that generates the various clock pulses or timing pulses mentioned above.
shows.

In the figure, 410a is a standard pulse generator (for example, 8640B manufactured by Suwa Seikosha), which generates a reference clock pulse of an arbitrary frequency by setting a switch group 410b. 410c
, 410f is a frequency divider (for example, RCA CD4040)
, 410d is a 1/10 frequency divider (for example, RCA CD4
017), 410e is a pulse generator (for example, RCA CD4017), 410g is a trigger generator (for example, RC
CD4017 manufactured by Company A), 410h is a clock generator (for example, CD4017 manufactured by RCA Company). 410i is a reset pulse SR generation circuit composed of a capacitor, a diode, and a buffer.

The rotational speed of the motor 3 is always kept exactly at the rotational speed of the rotating shaft 11, which is the set speed, by the motor drive signal Tn outputted from the control circuit 4 (see FIG. 1) having the configuration and operation as described above. The result display pointer 22 accurately indicates the rotational speed of the rotating body to which the rotating shaft 11 is connected.

That is, the motor-driven beam bow Tn is composed of the control signal TC shown in the above equations (1) and (2), and this control amount signal TC is a correction amount signal calculated according to each condition as shown in the above table. Corrected by HA and HB. In the correction amount signals HA and HB, the velocity difference absolute value data vd is a quantity that contributes to the responsiveness of making the speed of the motor 3 quickly follow the speed of the rotating shaft 11, and the acceleration absolute value data αd
is an amount that suppresses speed changes of the motor 3 and contributes to its stability. The driving DC motor 3 is accelerated or decelerated in accordance with the pulse duty of the control amount signal TC which is successively corrected by the correction amount signals HA and HB, and its rotational speed is accurately controlled.

Although the offset pulse signals T+0 and T-0 included in the motor drive signal Tn are not directly involved in controllability, they have the effect of applying dither to the motor 3, allowing the motor 3 to be started in a very low speed range.

Furthermore, a photoelectric sensor or the like may of course be used in place of the reed switch.

In this way, if the motor speed control device of the present invention is used for the rotational speed support needle, the speed display pointer can be operated by the drive motor that accurately follows the rotational speed of the rotating body, so the display pointer can There is no need to lay a meter cable between the rotor and the rotary body, so there is no need for space for this, and there is no cable fatigue, resulting in extremely high reliability. Furthermore, since the rotational speed range of the drive motor can be considerably wider than that of the meter cable, the accuracy of supporting the display pointer is also improved.

In the above embodiment, the control circuit is constructed of a hardware circuit, but it is of course possible to replace this with a microcomputer.

Furthermore, the optimum values for the constants K1 and K2 are selected by actually checking the control behavior of the motor.

As described above, the motor speed control device of the present invention exhibits extremely excellent performance and effects.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a rotation speed indicator using the motor speed control device of the present invention, and Fig. 2 shows a waveform shaping circuit and two
The circuit diagram of the multiplier circuit, Figure 3 is the time chart of various signals, Figure 4 is the circuit diagram of the speed difference detection circuit, Figure 5 is the time chart of various signals, and Figures 6 to 11 are the motor acceleration. Circuit diagrams of the detection circuit, correction amount calculation circuit, control amount calculation circuit, offset signal generation circuit, motor drive circuit, and timing pulse generation circuit, Figure 12 is a time chart of various signals, and Figure 13 is the rotating shaft speed and motor FIG. 3 is a diagram showing changes in speed over time. 1... Rotating body speed detection sensor (setting speed generation means) 3... Motor 27... Reed switch 40 for motor speed detection
3...Speed difference detection circuit 404...Motor acceleration detection circuit 405...
... Correction amount calculation circuit 406 ... Controlled amount calculation circuit Fig. 4 △V Fig. 5 (9) A 9th Fig. 10 Fig. 11 E 10 Fig. 12 (1) and F Tsui Old and old + Sbe (2) 5v (3) Old' Month IJI Ding/Sp+ (4)-Oki J Koguchi J'l)'51) 2 (5) 7-Bottom) Sc (6) -Riichi-- ---------1o CL2 (7)
Upper---) C10 (11) J-1-']rst (+2) Sf Fig. 13

Claims (2)

[Claims] (1) a set speed generating means for generating a speed set value that changes over time, a motor speed detecting means for detecting the rotational speed of the motor, and a speed difference calculation means for calculating the difference between the set speed and the motor speed; A motor acceleration calculation means for calculating the amount of change in the motor speed, and a correction amount signal calculated from the weighted average of the speed difference and the motor acceleration, and a motor control amount signal calculated from the correction signal, and the rotational speed of the motor and motor control means for outputting the control amount signal to the motor so that the motor speed matches the set speed. (2) The motor control means controls the absolute value v of the speed difference ΔV.
K1·vd is calculated from d and the first control constant K1, and the sum K1·vd of this and the absolute value αd of the motor acceleration α is calculated.
A correction amount calculation means that calculates vd+αd or the difference |K1·vd−αd|, takes it as a weighted average of the speed difference ΔV and the motor acceleration α, and outputs these as a correction signal HA for motor acceleration or a correction amount signal HB for motor deceleration. Then, from the above correction amount signals HA, HB and the second control constant K2, K2・HA
, K2・HB, and convert the previous motor control amount signal to TC.
-1, TC-1+K2・HA or TC-1-
2. The motor speed control device according to claim 1, further comprising control amount calculation means for converting K2·HB into a new motor control amount signal TC and outputting this to the motor.