JPS59177601A - positioning device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a movable member positioning device for printers, copying machines, facsimile machines, floppy disk devices, etc. that performs intermittent feeding via wires, belts, etc. It relates to a positioning device that is desired to be attenuated.

PRIOR ART Conventionally, position signal detection 57. L t+A was installed to detect the position and speed and control the Isuj part ↑, 1'.
+Wire 1 that has springiness, rather than a source or a completely rigid body
Since it is Hell 1~, etc., a phase difference is created between the motion of the movable parts 1 and 4 and the jIIIU power source, and the
Regarding the convergence of hunting when determining the goal, there was a drawback that it was difficult to achieve a fast and accurate tan pink or lie.

The present invention improves the above points. That is, at the time of tan pink! 51Rnf! The purpose of this invention is to amplify a signal obtained by adding a movable member acceleration signal in addition to a position signal and a speed signal of a source to control a drive source, thereby performing accurate dumbing of a movable member.

Embodiment FIG. 1 shows a block diagram of an embodiment of the positioning servo control system of the present invention. In Figure 1, 10
is a motor, in which a photo encoder (position detector) 11 that generates position signals with mutually different phases of π/2 as the rotor rotates, and a load (movable member) 29 controlled by the motor 10 are directly connected. Alternatively, they may be indirectly connected to each other and rotate and stop together with the motor 10. At the start of the operation, the movement distance command and position error counting device 25 outputs a signal indicating the distance and direction in which the movable member 29 should move (or rotate) as an output command signal, that is, the distance information is output as an initial value of the position error command signal. The signal is sent to the speed command signal generator 20, and the speed command signal Vc is determined based on its contents. That is, the larger the required moving distance of the load 20 is, the larger Vc is, and the motor 10 rotates at a higher speed.

On the other hand, the rotation direction instruction signal is sent to the selection circuit 24, and either the output signal (Vc-+vω+) of the inverting amplifier 22 or the output signal (Vc++Vω-) of the inverting amplifier 23 is selected and sent to the amplifier 28.

Now, when the motor 10 starts rotating, the photo encoder 11 outputs a signal indicating the unit movement amount of the load 29 by π/2.
Two periodic minute position signals having different phases by the same amount are detected. This signal is sent to the position signal amplifier 12, where it is amplified to a predetermined level to obtain a position signal A and a position signal B. These two signals may be sawtooth waves, sine waves, or similar waveforms. Two position signals A, B
is differentiated by differentiators 13 and 14, and the differential signal A'=dA/
dt, B' = dB/dt, and then rectified by full-wave rectifiers 16 and 17, and further rectified by full-wave rectifier adder 1.
8 is added. That is, the output of the aftereffect rectifier and adder 18 is a speed signal ω representing the actual speed of the motor 10. On the other hand, the position signals A and B are also sent to a position signal amplitude average value detector 19, and the amplitude fluctuations thereof are monitored and used to relatively cancel the fluctuations in the speed signal due to the amplitude fluctuations of the position signals. . The output of the position signal amplitude average value detector 19 becomes the input of the speed command signal generator 20. Further, the position signal B is also sent to the position pulse signal generator 15, and as the motor 10 rotates, a position pulse is output every time the load 29 moves a unit distance. As will be described later, this position pulse signal generator 15 is composed of a position signal Schmitt circuit, and the position signal amplitude average value detector 1 is used as its bias.
The signal obtained in step 9 is used to prevent the position pulse from shifting from the absolute position even if the amplitudes of the position signals A and B vary.

By the position pulse output of the position pulse signal generator 15, the contents of a well-known position error counter included in the moving distance command and position error counting device 25 are subtracted. The output of this position error counter is given to the speed command signal generator 20 as a position error instruction signal, and a speed command signal VC of a level corresponding to the distance between the target stop position of the load 29 and the current position is created. This speed command signal Vc
and the actual speed signal ■ω which is the output of the full-wave rectification adder 18 is V
c, Vω are added by the adder 21, and further added by the inverting amplifier circuit 2
In steps 2 and 23, the twice-inverted output is sent to the selection circuit 24, and one of the inverted outputs is selected to drive the motor 10. As the motor 10 rotates, the content of the position error counter decreases, and accordingly, the level of the speed command signal c also decreases, and the speed of the motor 10 decreases. In this way, when the content of the position error counter becomes zero and the load 29 reaches the target position, a target position arrival instruction signal is sent from the movement distance command and position error dividing device 25 to the selection circuit 2.
Output to 4. This blocks Vc and Vω,
Instead, position signal, differential signal and acceleration signal addition circuit 2
7, the position signal A, the differential signal A', and the acceleration signal α
The added signal is selected by the selection circuit 24 and sent to the amplifier 28.
, and the motor 10 stops.

As shown in FIG. 3, the acceleration signal generator includes a pressure sensitive element 9,
It is composed of an inertial body 8 and a spring system 7, and is installed on a movable member 29.

The pressure sensitive element is made of a material such as ceramic, and takes advantage of the property that its resistance value changes as the applied pressure changes.

Therefore, if a voltage is applied to the pressure sensitive element via a resistor, a change in pressure can be extracted as a voltage change.

When the movable member 29 is stationary, it is biased by the presser spring system 7 so that approximately 1/2 of the maximum pressure applied to the pressure sensitive element during damping is always applied to the pressure sensitive element. . Therefore, the acceleration signal amplifier 31 must be electrically biased so that its output is zero when the movable member is stationary.

FIG. 5 is a time chart of main signals for explaining the overall operation of FIG. 1, and particularly shows the case where the motor rotates in the forward direction. That is, a positive direction rotation instruction of the motor 10, that is, the negative mower 29, and its moving distance are outputted from the moving distance instruction and position error counting device 25, and accordingly, a speed instruction signal Vc+ is inputted to the amplifier 28, and the amplified voltage is output. is applied across the terminals of motor 10. As a result, the motor 10 starts rotating in the forward direction, and at the same time the position signal A
, B are output, and a speed signal Mω- obtained by differentially rectifying this position signal is also inputted to the amplifier 28. These ■c
+ and ■ω- have opposite polarities and always act to cancel each other out.

By the way, due to the rotor inertia, load inertia, etc. of the motor 10, the rotational speed of the motor 10 cannot immediately respond to changes in the speed command signal Vc, but accelerates and decelerates with a certain gradient. At the initial acceleration, (Vc+
)+(Vω-)>0, the motor current flows in the negative direction, and the motor 10 continues to accelerate. When the rotational speed of the motor 10 approaches the set speed based on the position error, (Vc+)+
(Vω-) becomes 0, the motor current becomes almost zero, and the motor rotates at a constant speed. As the motor 10 rotates, the content of the positional error counter decreases, and when a certain positional error is reached, the level of the speed command signal Vc+ is switched and decreased.

On the other hand, since the rotation of the motor 10 cannot respond immediately, (Vc+)+(Vω-)<0 temporarily, and the motor current flows in the opposite direction. That is, the motor 10 is decelerated along with a decrease in the speed command signal c+. Thereafter, similar operations are repeated one after another, and when the load 2g reaches the target position, the content of the position error counter becomes zero, and a target position arrival instruction signal is output to the selection circuit 24. As a result, (Vc+)+(Vω
-) is blocked and replaced by the position signal A and its differential signal A.
', the acceleration signal α is input to the amplifier 28, and the motor 10
stops while tamping.

FIG. 2 shows a specific configuration example of the main circuit in FIG. 1, and the same parts as in FIG. 1 are given the same reference numerals.

FIG. 4 shows the main signal waveforms during the constant speed period shown in FIG. 2. Now, when the position signal A is input to the capacitor C31 of the differentiator 13, if dA/dT≦0, the differential waveform determined by the constant of the differentiator circuit consisting of C31 and the resistor R32 is the connection between the capacitor C31 and the resistor R32. This is input to the Vc, Vω adder 21 through the resistors R33 and R34 of the full-wave rectifier 16 and the resistor R36 of the full-wave rectifier adder 18. Note that when the input is negative, the output of the operational amplifier OP37 of the full-wave rectifier 16 becomes positive, so in this case, the output of the operational amplifier OP37 is separated from the differential signal by the diode Di35. On the other hand, if dA/dt≧0, C3
1 and the constant of resistor R32 is the differential waveform of capacitor C.
31 and resistor R32, this is multiplied by R34/R33 by the full-wave rectifier 16, and passed through resistor R36 to V
c and Vυ are input to the adder 21. The above operation is the same for the position signal B, and in this way the position signal A
, B are added by the full-wave rectification adder 18 and sent to the Vc, Vω adder 21. It goes without saying that similar results can be expected if the platform employs a full-wave rectifier circuit, or if position signals A and B are inverted and a total of four position signals are half-wave rectified.

Blocks 19 and 20 in FIG. 2 are specific examples of the configuration of circuit portions for obtaining the speed command signal Vc and the bias voltage for generating position pulses. Here, the position signals A and B are from the operational amplifier OP41.
, OP42, and a total of four position signals A, B, A,
The negative peak values of B are each sampled and held by a diode and a capacitor. For example, diode Di43
The capacitor C44 serves as a sampling and holding circuit for the signal A obtained by inverting the position signal A. These 4
When the two signals are summed, the output side of the operational amplifier OP47 is the average value of the amplitudes of the position signals A and B, that is, FB2=K(lA
l+lBl) is obtained. However, K is a proportionality constant.

By using this as a reference signal when creating a speed command signal, it is possible to relatively cancel fluctuations in the speed signal when the amplitudes of the position signals A and B change. Note that the voltage generated by the diode Di1 and the resistor R1 is input to the operational amplifier OP47 via the resistor R2, which compensates for the temperature-induced drift of the diode Di43 and other three similar diodes. Further, the diode Di2 is connected to the negative power supply from the sampling hold section which is the contact point between the diode Di43 and the capacitor C44, and this is to prevent the capacitor C44 from discharging when the device is at rest. The same applies to other sampling and holding circuits.

The speed command signal generator 20 consists of a circuit group of a plurality of resistors and switches connected in parallel between the position signal amplitude average value detector 19 and the ■c, ■ω adder 21, and the switch of each circuit. The on/off control of is determined by the moving distance command and the position error content of the position error counting device 25. That is,
When the position error is large, the selected resistance is small and the speed command signal current supplied from the speed reference signal FB2 to the Vc and VC adder 21 is large. Conversely, the smaller the position error, the larger the resistance selected. Here, the smallest circuit for the speed command signal is resistors R44, R47, and diode D.
i5, Di6, AND circuit IC5, diode Di3,
There is Di4, which is a circuit added specifically due to the timing of speed command signal switching and restrictions on switch elements. Diodes Di5 and Di6 are ■AND when 1 is low
The VOL of circuit IC5 is absorbed here to prevent leakage current. Diode Di3 of position signal amplitude average value detector 19
, Di4 are for compensating for the temperature drift of the diodes Di5 and Di6 when ■1 is high. The resistor R44 has the role of absorbing Ioh of the AND circuit IC5 when V is high and suppressing fluctuations in the speed command signal current in this circuit. As is clear from the above explanation, the circuit of the speed command signal generator 20 can be constructed using only an IC, a resistor, and a tie.

The position pulse generator 15 is a circuit that uses the speed reference signal (or position signal amplitude average value) FB2 as a bias to generate position signals B and B using a resistor R43 and a Schmitt IC1, and a resistor R42 and a Schmitt IC2, respectively.

Differential circuit 26, position signal, differential signal and acceleration signal are transmitted through resistors R8, R9. R10, R11, and a capacitor C32, the position signal A is passed through the resistor R9, the differential signal A' determined by the capacitor C32 and the resistor R11 is routed through the resistor R10, and the acceleration signal α is routed through the resistor R8. and are sent to the selection circuit 24, respectively.

The selection circuit 24 is a moving distance command and position error counting device 2.
The output of the inverting amplifier 22 or 23 is selected until the position error content of 5 becomes zero, and when the position error content becomes zero and the target position arrival instruction signal is output from the device 25, the position signal,
The output of the differential signal and acceleration signal addition circuit 27 is selected. Note that the timing at which the destination position arrival instruction signal is issued is not at the complete target position as shown in FIG. 5, but is 1/8 period of the position signal before the target position in a strict sense. The signal selected by the selection circuit 24 is input to the operational amplifier ○P28 of the amplifier 28 and is amplified. However, when the input value exceeds a certain value, the voltage Vs at the connection point between the resistor R12 and the diode Di7 increases to It is saturated to a constant value by a constant voltage circuit made up of resistor R13. On the other hand, a motor current output resistor R16 is connected in series with the motor 10, and a voltage 1 is generated by the motor current.

Since the human power impedance of driver DR1 is very large, it can be equivalently set as V2=1×R16, and from this, motor current 1=.

Therefore, when ■s is saturated, the motor current becomes constant. As shown in this embodiment, the method of grounding one end of the motor current secreting resistor R16 and detecting the current value from the other end is applied when the driver DRV1 is of T type, but when DRV1 is H In the case of the motor type, similar current feedback is possible by detecting the voltage between both terminals of a motor current detection resistor connected in series with the motor 10.

Some conventional constant current circuits have a Zener diode connected in parallel with the feedback resistor of an operational amplifier, but with this method, the operating resistance of the Zener diode changes in response to the input signal, making it difficult to obtain a perfect saturation voltage. That's funny.

In the above explanation, the position of the movable member is used as a detector and the photo encoder type is used.
It does not matter if the position detector is what is called an inductosin.

In addition, regarding how to output the actual speed signal of the movable member, in this example, the explanation was given as requiring a position signal with a π/2 phase difference, but technically it is possible to output the actual speed signal from a single position signal. It is.

That is, it is a matter of course that the present invention does not need to be specified in any way regarding the means for detecting the position signal and the actual speed signal.

Effects In the conventional method, when using an elastic transmission means such as a wire or a belt, it is difficult to accurately control the movable member. By directly monitoring the movement of the movable member and providing feedback as in the present invention, more accurate control becomes possible.

[Brief explanation of drawings]

FIG. 1 is an overall block diagram of an embodiment of the present invention, FIG. 2 is a diagram showing a specific configuration example of the main parts in FIG. 1, and FIG.
The figure shows the default configuration of the acceleration signal generator, Figure 4 is a major signal waveform diagram when the motor rotates at a constant speed, and Figure 5 is a major signal waveform diagram to explain the overall operation of Figure 1. It is. 7... Spring, 8... Inertial body, 9... Pressure sensitive element 10
...Motor, 11...Photo encoder (position signal detector), 12...Position signal amplifier, 13, 14...
・Differentiator, 15...Position pulse signal generator, 16, 1
7...Full wave rectifier, 18...Full wave rectification adder, 19
... Position signal amplitude average detector, 20... Speed command signal generator, 21... Vc, Vω adder, 22... Inverting amplifier, 23... Inverting amplifier, 24... Selection circuit,
25... Movement distance command and position error counting device, 26.
...Differential circuit, 27...Position signal, differential signal and acceleration signal addition circuit, 28...Amplifier, 29...Load, 3
0... Acceleration detector, 31... Acceleration signal amplifier Patent applicant Ricoh Procedures Ne. , Relationship with the case of the person making the amendment Patent applicant J711Ko In addition to the acceleration signal, a speed signal is also effective as this feedback signal, and the position signal and speed signal of the driving body can also be used during damping. This can be obtained by integrating with an integrating circuit such as an operational amplifier.Furthermore, so far we have talked about DC motor control, but it goes without saying that it can also be applied to pulse motor control.''8

Claims (1)

[Claims] a motor for driving a movable member with a wire, a belt, etc.; a means for obtaining an acceleration signal of the movable member; a means connected directly or indirectly to the rotating shaft of the motor to generate a periodic position signal; means for obtaining signals obtained by differentiating the signals; means for obtaining an actual speed signal of the motor from the differential signals; means for selecting a signal obtained by adding a velocity signal, and selecting a signal obtained by adding a position signal, its differential signal, and an acceleration signal indicating the acceleration of the movable member near the target position; and amplifying the selected signal. and an amplifier for supplying power to the motor.