JPS6043701A - Digital error detector - Google Patents

Abstract

PURPOSE:To obtain an error detector for electric servo device which can detect an error by comparing a target signal of the pulse train signal applied with a digital signal with a displacement signal given from a displacement detector and applied with a pulse train signal similar to said target signal. CONSTITUTION:The pluse time is standardized by a pulse arraying circuit 10 for a target signal 7a which is produced by an error detector 4 synchronously with the rotor of a target signal 7. A displacement signal 6a which is produced synchronously with the rotational frequency of a displacement signal 6 given from a displacement detector 3 is also standardized by a pulse arraying circuit 11. A simultaneous pulse detector 13 discriminates the input timing of both a target signal 10a and a displacement signal 11a which are standardized respectively. Then a signal 13a shwoing the presence or absence of a simultaneous pulse is delivered. A double pulse generator 12 produces a target count signal which is counted from two input signals 10a and 11a by an error counter 15, a displacement count signal and a double pulse signal of the same time point. Then a control circuit controls the circuit 15 with a target revolving direction signal 7b and a displacement revolving direction signal 6b, etc.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a digital control device for an electric servo device that constitutes a drive mechanism section of mechatronics-related products, etc.
In particular, the present invention relates to a digital error detector suitable for detecting an error by comparing two pulse train signals given as digital signals.

[Background of the invention]

As an error detector related to a conventional digital control device of an electric servo device, for example, an initial error with a target value is preset in an error counter, and each time a pulse signal is generated from a displacement detector, the contents of the error counter are There is a method that detects the error from the target value by subtracting or adding. However, with this method, for example, in electric servo devices such as magnetic tape devices that continuously feed magnetic tape, the amount of displacement of the magnetic tape is enormous, so the configuration of the counter section of the error detector is It had drawbacks such as being too large to be implemented. As another example of a conventional error detector, a target signal giving a target value is generated as a pulse signal one after another in the same way as a pulse signal from a displacement detector, and two pulse train signals given as digital signals are compared. There are methods that detect errors from the difference in relative pulse numbers. However, this method has a counter that counts the target signal and the pulse signal from the displacement detector, and the error between the two counters can be subtracted. In electric servo devices such as magnetic tape devices that continuously feed magnetic tapes, the counter has a large capacity, making it difficult to implement.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art by comparing a target signal of a pulse train signal given by a digital signal and a displacement signal from a displacement detector given by a pulse train signal similar to this target signal. It is an object of the present invention to provide a digital error detector such as an electric servo device that can easily detect errors.

[Summary of the invention]

In order to achieve the above object, the present invention increases or subtracts an error counter each time a pulse signal is generated from a target signal generator and a displacement detector, thereby increasing the capacity of the error counter to cover the range of the error amount. In addition to reducing the error counter capacity, the above pulse signal is
This digital error detector is characterized in that the error counter is configured so that it does not malfunction even when two errors occur simultaneously. [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be explained with reference to FIGS. 1 to 5. FIG. 1 is a block diagram illustrating the overall configuration of an electric servo device implementing the present invention. In Figure 1,
1 is a motor, 21'l is a load, 3 is a displacement detector (encoder), 4 is an error detector, 5 is a controller, 6 is a displacement signal from the displacement detector 3, 7 is a target signal generator (not shown) 8 is an error signal, and 9 is a drive signal.

With this configuration, the motor l rotationally drives the load 2, and the amount of rotational displacement thereof is detected by a digital displacement detector 3 directly connected to the shaft of the motor l. This displacement detector 3 is generally called an encoder, and generates a displacement signal (Noculus signal) 6 every time it rotates by a predetermined angle. This displacement signal 6 usually consists of two human phase and B phase signals that differ in phase by 90 degrees for the purpose of determining the direction of rotation.

Therefore, in order to simplify the explanation, the displacement signal 6 is a displacement rotation direction signal indicating the rotation direction that can be determined from the displacement signal (pulse signal) 5a and its phase, which is either the human phase signal or the B phase signal. (Flag signal) 6b. 'Similarly, regarding target signal 7, a target signal (pulse signal) generated in synchronization with the amount of rotation (amount of displacement)
7a and a target rotation direction signal (flag signal) 7b indicating the rotation direction. Target signal 7 with this configuration
and the displacement signal 6 from the displacement detector 3 are compared by the error detector 4, and a difference signal 8 is generated.

Then, the controller 5 receives this error signal 8 and generates a drive signal 9 for driving the motor 1 having the load 2 in order to control the electric servo device with a predetermined performance.

Next, FIG. 2 is a block diagram showing the configuration of an embodiment of a digital error detector according to the present invention implemented in the error detector 4 of FIG. 1. In FIG. 2, the same reference numerals or symbols indicate the same or corresponding parts throughout the drawings, including 10.11 a pulse alignment circuit, 12 a double pulse generator, 13 a simultaneous pulse detector, and 14. 1 is a counter control circuit, 15 is an error counter, and 16 is a code counter.

With this configuration, the target signal 7a generated in synchronization with the rotation amount of the target signal 7 is standardized in its pulse width and rising pulse time in the pulse alignment circuit 10. Similarly, a displacement signal 6a generated in synchronization with the rotation amount of the displacement signal 6 from the displacement detector 3.
The pulse width and rising pulse time are similarly normalized in the pulse alignment circuit 11. FIG. 3 is a timing diagram illustrating the normalization operation of the target signal (pulse signal) 7a in the Noculus alignment circuit 10, for example. In other words, A in FIG. 3 is the target signal () (ruth signal) 7a, B is the reference clock signal CLK%C is the signal after the target signal 7a of A is delayed by one time from the clock signal CLKK of B. Aji, the clock signal CLK whose rising pulse time is B
You can see that it is synchronized with. D is a signal after being delayed once again by the clock signal CLK of B. The resulting signal is delayed by one cycle time t of the B clock signal CLK compared to the C signal. E is a signal obtained by taking the AND of the signals C and D, and F is a signal obtained by taking the exclusive OR of the signals C and E, that is, the output signal (normalized target signal) 10a of the pulse alignment circuit 10. It can be seen that the pulse width (t 2 ) l: upper pulse time of the target signal 7a of A is standardized with respect to the clock signal CLK of B.

Similarly, the normalization operation of the displacement signal (pulse signal) 5a in the pulse alignment circuit 11 is also performed at the same timing.

Next, the target signal 10a and the displacement signal 11a standardized by the pulse alignment circuits 10 and 11, respectively, are subjected to a simultaneous pulse detector 13 to determine the input timing of the two signals. FIG. 4 is a timing diagram of two signals for explaining the discrimination operation in the simultaneous pulse detector 13. That is, Gl, G2 . G3 is a standardized displacement signal 11a, and G1, G2 . Since the pulse width and rising pulse time of any standardized displacement signal 11a of G3 are standardized, the rising pulse time of N3 is
Since they are lined up every cycle time t of the clock signal CLK, which is the reference of D in the figure, the timing of the standardized displacement signal 11a of G1, G2 and G3 and the standardized target signal 10a of F is as shown in the figure. The figure shows that the input timings of the G2 standardized displacement signal 11a and the F standardized target 1g signal 10a are the same. Thus, when the input timings of two signals are equal, the simultaneous pulse detector 13 determines this and generates a simultaneous pulse signal (flag signal) 13a as an output signal indicating the presence or absence of a simultaneous pulse.

One of the double pulse generators 12 has a pulse alignment circuit 1 which has a standardized target signal 1 from each of the double pulses 10 and 11.
In addition to generating two input signals, 0a and displacement signal 11a, a target count signal H and a displacement count signal to be counted by the error counter 15, two input signals (pulse signals) are also generated. A double pulse signal J is generated which becomes a count signal when generated at a certain time.

Next, the counter control circuit 14 is connected to the double pulse generator 12.
The function is to control the error counter 15 by instructing whether the error counter 15 should add, subtract, or prohibit counting for the three types of count signals generated in the target count signal H, displacement count signal, and double pulse signal J. It is a logic circuit with In other words, the signal input to the counter control circuit 14 includes three pulses from the double pulse generator 12 described above.
In addition to the type of count signal, the presence or absence of simultaneous pulses of the target rotation direction signal 7b indicating the rotation direction of the target signal 7 and the displacement rotation direction signal 6b indicating the rotation direction (displacement direction) of the actual displacement signal 60 is detected. Error code signal 8 of error signal 8 from code counter 16 at the end of simultaneous pulse signal 13a shown in FIG.
There are four types of 72g signals of b, and the counter control circuit 1
4 receives these four types of flag signals', that is, the conditions of the four types of flag signals, that is, the error code signal 8b, the target rotation direction signal 7b, and the displacement rotation direction signal 6b.
, the error sign of the simultaneous pulse signal 13a is positive or negative, the target rotation direction is normal or reverse, the displacement rotation direction is normal or reverse, and the error counter 15 is set according to the conditions of the presence or absence of simultaneous pulses. It displays whether the count contents, that is, addition (count up) operation and subtraction (countdown) operation, are target count signal H, displacement count signal (or both signals), and whether counting is prohibited.
For example, in the case of the condition indicated by K in the figure, the error sign is positive, the target rotation direction is the forward rotation direction, the displacement rotation direction is also the forward rotation direction, and there is no simultaneous pulse. , the target signal 7a generated in synchronization with the amount of rotation of the target signal 7 and the target count signal H generated via the Lahalse alignment circuit 10 and the double pulse generator 12 are added, and the displacement signal 6 from the displacement detector 3 is obtained. The error counter 15 is instructed to subtract the displacement count signal generated via the pulse alignment circuit 11 and the double pulse generator 12 from the displacement signal 6a generated in synchronization with the amount of rotation. Then, in response to this command, the error counter 15 performs the above-described predetermined counting operation, and outputs the result as an error signal 8a indicating the amount of error in the error signal 8 and an error code signal (flag) indicating the error code determined by the sign counter 16. signal) 8b
Output as . The role of the sign counter 16 is that the error counter 15 can only perform unidirectional calculations, so it cannot function if the content of the error counter 15 becomes negative. The sign is discriminated from the error signal 8 and displayed, thereby allowing the error counter 15 to perform only absolute value calculations, thereby allowing negative calculations 4 to be performed. In this way, the error detector 4 compares the displacement signal 6 from the displacement detector 3 with the target signal 7, detects the relative pulse number error, and generates the error signal 8. In response, the controller 5 generates a drive signal to the motor 1 having the load 2, so that the electric servo device can be controlled with a predetermined performance.

As described above, according to this embodiment, the capacity of the error counter is increased by adding or subtracting the error counter each time a pulse signal of the target signal and displacement signal is generated from the target signal generator and the displacement detector. The circuit is constructed so that the capacity can be reduced by covering the range of the error amount, and the error counter does not malfunction even when two pulse signals of the target signal and the displacement signal are generated at the same time.

〔Effect of the invention〕

According to the digital error detector of the present invention, it is possible to accurately and stably detect a relative pulse number error by comparing two pulse train signals using a small-capacity error counter that can cover the range of the error I. For example, it can be widely and effectively used in electric servo devices that continuously feed magnetic tape or the like that undergoes a huge amount of displacement.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating the overall configuration of an electric servo device, FIG. 2 is a block diagram illustrating an embodiment of the digital error detector according to the present invention, and FIG. 3 is a normalized operation timing diagram of FIG. Figure 4 shows 21...Motor, 2...Load, 3...Displacement detector, 4...Error detector, 5...
・Controller, 10.11...Pulse alignment circuit, 12...
- Double pulse generator, 13... Simultaneous pulse detector, 14... Counter control circuit, 15... Error counter, 16... Sign counter. 1st Ward X Z Figure No. 3121 4th (2)

Claims (1)

[Claims] Means for standardizing the pulse width and rising Luhalus time of two input pulse train signals, determining the input timing of these two standardized pulse signals, and generating a flag signal indicating this when input at the same time means for generating a count signal to be counted from these two standardized pulse signals; and a logical control signal for receiving a predetermined flag signal necessary for counting the count signal and controlling the counter. means for detecting a relative pulse number error between the two pulse train signals by performing a predetermined count each time the count signal is generated based on the logic control signal; and means for determining the sign of the contents of the counter. A digital error detector comprising means for generating a flag signal indicating this.