JP3259469B2 - Recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recorder for receiving various input signals in a plant or the like and performing analog recording on recording paper in accordance with the level of the input signal.

[0002]

2. Description of the Related Art A recorder is an apparatus which operates in response to an external input signal to record a measurement signal on recording paper in an analog manner. Conventionally, there are various types of components. All recorders include a recording pen, a holding table for holding the recording pen, and a servo mechanism for moving the holding table to a predetermined position on the recording paper. A specific configuration is shown in FIGS. 7 to 9, for example.

The recorder shown in FIG. 7 includes a motor 31 for moving a holding table of a recording pen, and a pen position detecting circuit 32 for detecting a current position of the recording pen by a resistance brush method or the like.
And a servo amplifier 33 that receives the pen position data and the pen position command data from the pen position detection circuit 32 and drives the motor 31 so as to match the two.
The recorder shown in FIG. 8 includes a motor 31, a pen position detection circuit 32, a CPU 34 for receiving pen position command data and pen position data to calculate control output data, and a CPU 34.
D / A for converting control output data from the controller into an analog signal
It comprises a converter 35 and a motor driver 36 that drives the motor 31 according to a signal from the D / A converter 35.

The recorder shown in FIG. 9 comprises a motor 31, a pen position detection circuit 32, a servo amplifier 33, and a CPU 34.
, A D / A converter 35, and a motor driver 36. However, the recorder of FIG. 7 employs an analog control method, and in particular, has a problem that sufficient control performance cannot be obtained near a target value. 8 and 9
Since the recorder uses a D / A converter, in order to perform high-precision control using the CPU, the D / A converter must be inevitably increased in precision, and the price of the apparatus increases. Problem.

[0005] In order to solve the above-mentioned problems, the present applicant has already filed a recorder that includes a drive / control means, a proportional control means, and an integral control means and performs motor control with high accuracy. (Japanese Patent Application No. 4-31829).

[0006]

The recorder according to the above-mentioned application has improved accuracy as compared with the conventional one, but it basically has a high speed (constant speed) due to a large deviation while performing proportional control. ) When the deviation is reduced from the movement to the low-speed (constant speed) movement, the drive to the motor is interrupted, and the speed is changed to the low-speed movement after reaching a predetermined speed. (For example, a gear reduction system), an inertia of a pen drive system or the like causes a phenomenon that the pen goes too far, which causes a problem that hunting and overshoot occur in pen position control.

In order to prevent this, it is conceivable to lower the speed at a stage where the deviation is relatively large. However, in this case, there is a problem that the response is poor. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a recorder which does not cause hunting or overshoot while ensuring responsiveness.

[0008]

SUMMARY OF THE INVENTION A recorder according to the present invention receives command signals from the outside and calculates a command value for the position of the recording pen in accordance with the input signal. Pen position detecting means for detecting the position of the pen, the command value calculating means, a deviation calculating means for receiving the output of the pen position detecting means and calculating a deviation between the two outputs, and several steps of setting depending on the magnitude of the deviation. A motor for driving a pen that moves at a high speed, a unit that outputs a command for moving the pen at a constant speed, and a pen movement that calculates a pen moving speed according to a change in pen position detected by the pen position detecting unit. A speed calculating means for outputting a constant speed movement command, a reverse rotation constant speed movement command, and a stop command in accordance with the deviation and the rate of change of the pen movement speed; Reverse rotation or A driving / braking means for outputting a command of stop, the proportional control means for performing control in accordance with the output of the deviation calculation means, despite the operation of the proportional control means,
When the recording pen does not move, integration control means for moving the recording pen toward the command value based on the gradually increasing data is provided.

In this recorder, in addition to the pen position detecting means, a pen moving speed calculating means is provided. When the deviation becomes small and the vehicle shifts to a low speed, a reverse braking command is given to the motor. Shooting is avoided.

[0010]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a block diagram illustrating a recorder according to an embodiment of the present invention, particularly focusing on a servo mechanism. The apparatus includes a CPU 1 receiving pen position command data and a feedback signal, an addition circuit 2 for converting a digital output (motor operation signal) of the CPU 1 into an analog signal, and a motor driver 3 receiving the output of the addition circuit 2
A DC brushless motor 4 driven by the output of a motor driver 3, a pen driving mechanism 5 for moving a recording pen (not shown) according to the rotation of the motor 4, and a pen position for detecting the position of the recording pen A for giving a feedback signal corresponding to the pen position to the detection circuit 6 and the CPU 1
/ D converter 7.

Although only one recording pen circuit is shown here, the adder circuit 2, motor driver 3, motor 4, and recording pen driving mechanism 5 are individually provided for n recording pens. Have. Further, the pen position command data is data given from the main CPU 8 every 100 ms, for example, and is data for commanding the recording pen position calculated according to the input signal supplied to the recorder.

The CPU 1 is a so-called one-chip microcomputer, and the processing content is shown in a functional block diagram as shown in FIG. That is, the CPU 1 receives the feedback signal and calculates the pen position.
And a deviation calculator 10 for calculating a deviation between the calculated pen position data and pen position command data from the main CPU 8.
And a pen speed calculator 11 for calculating the pen moving speed based on the previous pen position data and the current pen position data, an integration calculator 12, and a drive / brake controller 13. The drive / brake control unit 13 includes a motor rotation speed command calculation unit 14 and a polarity determination unit 15. The motor rotation speed command calculation unit 14 shows a pen speed (motor rotation speed) -deviation curve shown in FIG. 3 as a servo control characteristic, and is set to an optimum value in advance. In FIG. 3, α is as small as possible (approximately 10%), and the characteristic is such that pen overshoot hunting does not occur. The difference between this setting curve and the actual pen speed is the speed deviation. There is provided a two-dimensional table for determining the next pen speed in accordance with the speed deviation and the pen position deviation input from the position deviation calculation unit 10, whereby the rotation speed and the rotation direction (polarity) of the motor are determined. A bit signal is output. In the curve of FIG. 3, when the deviation is in a range smaller than α and in a region above the curve, if the distance is far from the curve, a high-speed, reverse rotation command value is issued, and the pen is suddenly braked. It has become.

FIG. 4 is a circuit diagram of the adder circuit 2. The switch S4 operates according to a U / D discrimination signal (bit 4) output from the polarity discriminator 15, and a motor rotation speed command. A switch S3 that operates according to a motor operation signal (bit 3 to bit 0) output from the arithmetic unit 14
To resistors S3 to R0 connected to the switches S4 to S0, and having a resistance value ratio of 1: 2: 4: 8.
The differential amplifier 16 includes a differential amplifier 16 that adds the voltages supplied through 3 to R0 in accordance with the resistance ratio, and a feedback resistor Rf. Then, the switch S4 determines whether to perform the U / D determination (up /
ON / OFF operation according to the data
A voltage of +15 V or -15 V is supplied to the switches S3 to S0. That is, the data of bit 4 output from the polarity determination unit 15 functions as a forward / reverse rotation command signal for the motor 4.

The pen drive mechanism 5 includes a reduction gear connected to the motor 4, a pulley, a thread, a pen holding mechanism, a pen holding mechanism moving guide, a recording pen, and the like. The recording pen is moved by the pen driving mechanism 5 within a range of 0 mm to 100 mm. The pen position detection circuit 6 is a so-called non-contact potentiometer based on an electromagnetic induction method or the like, and has, for example, a configuration shown in FIG. That is, the pen position detecting circuit 6 is provided with the sense coil circuit 1 laid in front of the recording pen moving range.
7, an excitation coil 18 for generating a magnetic field at the pen tip of the recording pen, an excitation circuit 19 for driving the excitation coil 18,
A circuit switch 20 for sequentially switching the connection with the sense coil, a signal amplifier 21 for amplifying an electromagnetic induction signal from the sense coil, and an A / D converter for converting the output of the signal amplifier 21 into a digital signal 22 and a CPU 23 for controlling the entire operation. The circuit switch 20 and the A / D converter 22 operate based on a switching command from the CPU 23, an A / D start command, and the like.
By inputting the output of the converter 22 to the CPU 23, the pen position can be accurately detected.

Next, the overall operation of the recorder of the embodiment will be described. When pen position command data is input from the main CPU 8 to the servo CPU 1, the pen position command data is added to the position deviation calculation unit 10 of the servo CPU 1.
On the other hand, the pen position detection / calculation section 9 calculates the current position of the pen based on the feedback signal input to the pen position detection / calculation section 9 of the servo CPU 1 via the A / D converter 7. The pen position data is added to the position deviation calculator 10, and the position deviation calculator 10 calculates the deviation at that time. This deviation is added to the driving / braking operation unit 13. If this deviation is larger than α shown in FIG. 3, the motor circuit speed command operation unit 15 outputs bits 0 to 3 indicating the high-speed (constant speed) operation of the motor. A signal is output to the addition circuit 2 and a bit 4 signal for approaching the target position is added to the addition circuit 2 by the polarity determination unit 15 according to the polarity of the deviation. The adder circuit 2 converts the input signals of bits 0 to 3 into analog signals, and inputs the signals to the motor driver 3 with a polarity corresponding to the bit 4 signal indicating the polarity. In response, the motor 4 is driven to rotate at a constant speed, and the recording pen of the recording pen driving mechanism 5 is moved so as to approach the target position. In this state, the pen speed calculator 11 calculates the pen speed from the previous pen position and the current pen position, and inputs this to the drive / brake controller 13. Until the deviation becomes smaller than α, the high-speed constant-speed movement at the rotation speed W of the motor continues. Eventually, when the deviation becomes smaller than α, the set rotation speed of FIG.
With respect to the deviation curve, the motor has a large motor rotation speed due to the inertia of the deceleration system or the like, and the pen speed calculated by the pen speed calculation unit 11 also becomes large. Therefore, a deviation occurs between the actual calculated pen speed and the pen speed of the setting curve.
The drive / brake control unit 13 inputs the calculated speed deviation and pen position deviation into a two-dimensional table, reads out a target pen speed, and outputs a bit signal of the rotation speed and rotation direction (polarity) of the corresponding data. Is output to the addition circuit 2. In this state, ie, when the deviation is smaller than α, if the actual control point moves largely to the upper area with respect to the set curve, a signal indicating that the motor rotates in reverse at high speed (high-speed reverse Rotation command). As a result, sudden braking is applied, and when the actual control point enters an area below the set curve, the reverse rotation is stopped. When the deviation decreases and the control point enters the upper area again, a reverse rotation command is output again. By repeating the reverse rotation command and the stop command in this way, the actual motor rotation speed-deviation curve is controlled so as to approach the set curve.

Further, the pen position deviation value is a dead band width ± d / 2.
If the pen position deviation value is still the same as the previous value, that is, if the pen has not moved, even in the proportional control state, the integration operation unit 12 counts and calculates the same number of times. Is generated N times, the drive / brake control unit 13 outputs the next higher speed and the polarity according to the positive or negative of the deviation. As a result, despite the proportional control operation,
When the pen does not move, the pen movement functions, and can effectively cope with aging of the drive system of the recording pen. When the deviation is smaller than d / 2, the motor stops.

FIG. 6 is a flowchart showing the above operation. When the processing operation is started, first, in step ST
In step 1 (hereinafter referred to as ST), a deviation between the pen position and the pen command is obtained, and this deviation is larger than α in FIG. 3, or smaller than −α, −α ≦ deviation ≦ α, or −α / 2 <deviation. It is determined whether <α / 2 (ST2). Initially, if the deviation is very large, -α> deviation or α <deviation,
It is moved at the maximum speed (constant speed) in the direction determined by the sign of the deviation (ST3).

If the deviation becomes equal to or more than -α and equal to or less than α at several processing timings, it is determined whether the same deviation has continued n times or more compared with the previous time (ST4), and the deviation changes. In this state, the pen speed is calculated from the previous and current pen positions (ST5), the speed set value is calculated from the curve in FIG. 3 (ST6), and the pen speed-speed set value is calculated.
A speed deviation is obtained (ST7). Then, the rotation direction and the rotation speed are obtained by referring to the two-dimensional table from the deviation and the speed deviation (ST8). When the pen does not move even though the deviation is equal to or more than -α and is within α, if the same deviation continues n times or more,
That is, by the integration operation, the determination of ST4 becomes YES,
In ST9, a speed command of a level one level higher than the previous time is issued.
Eventually, when the deviation becomes larger than -α / 2 and becomes smaller than α / 2, the operation is stopped (ST10).

[0019]

According to the present invention, a pen speed calculating means is provided in addition to the pen position detecting means, and a braking command is given by reverse rotation of the motor when the deviation becomes small and the high-speed movement is shifted to the low-speed movement. So, without reducing the response speed,
Still, a recorder free of hunting and overshoot can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a part of a recorder according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a functional configuration of a servo CPU constituting the recorder of the embodiment.

FIG. 3 is a diagram showing motor rotation-deviation characteristics set in a servo CPU of the embodiment.

FIG. 4 is a circuit diagram of an adder circuit constituting the recorder of the embodiment.

FIG. 5 is a circuit diagram of a pen position detection circuit constituting the recorder of the embodiment.

FIG. 6 is a flowchart for explaining the operation of the recorder of the embodiment.

FIG. 7 is a block diagram illustrating a conventional recorder.

FIG. 8 is a block diagram illustrating a conventional recorder.

FIG. 9 is a block diagram illustrating a conventional recorder.

[Explanation of symbols]

 9 Pen position detection calculation unit 10 Position deviation calculation unit 11 Pen speed calculation unit 13 Drive / brake control unit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01D 15/24

Claims (1)

(57) [Claims] 1. A command value calculating means for receiving an input signal from the outside and calculating a position command value of a recording pen according to the signal, a pen position detecting means for detecting an actual position of the recording pen, A value calculating unit, a deviation calculating unit that receives an output of the pen position detecting unit, and calculates a deviation between the two outputs, a pen driving motor that performs several steps of constant speed movement in accordance with the magnitude of the deviation, Means for outputting a command for moving at a constant speed; pen moving speed calculating means for calculating a pen moving speed according to a change in pen position detected by the pen position detecting means; and a change in the deviation and pen moving speed Outputs constant speed movement command, reverse rotation constant speed movement command, stop command according to the rate,
When the deviation decreases from the high-speed movement and moves to the low-speed movement, the drive / reverse rotation / stop command is output to the motor.
Braking means, proportional control means for performing control in accordance with the output of the deviation calculating means, and in spite of the operation of the proportional control means, when the recording pen does not move, toward the command value based on the gradually increasing data. A recording device comprising: an integral control means for moving a recording pen.