JP2001201367A - Pulse hysterersis compensating method and its device for jitter removing circuit and recording medium recorded with its operating procedure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve an occurrence of pulse hystersis during motor reversal which is a problem in position detection of an encoder using a conventional jitter removing circuit. SOLUTION: A signal processing circuit 3 of the encoder is a means removing jitters occurring before edges of rectangular wave signals of the encoder 2 outputting two phase rectangular wave signals with a mutual 90 deg. phase difference with respect to a displacement of a detected object 1. The two phase rectangular signals and their inverted signals are used as input signals for a set of four RS flip-flops, and a logical product of outputs of two-set RS flip-flops of the set of four RS flip-flops and a logical product of outputs of another two-set RS flip-flops different from the first two are determined for outputting two of phases rectangular wave signals with a 90 deg. phase difference having no jitters on edge parts. In the compensating method, edges of the two phases of rectangular wave signals outputted from the signal processing circuit 3 are counted, and when it is judged that a sign of a difference of the count value and a stored count value has changed due to reversal of a motor (steps 21 to 23), +1 or -1 is added to the count value in accordance with the sign of the difference and outputted (step 25 and 26).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing circuit for an encoder used for detecting the speed and position of a rotating body, for example, a motor, and to improve jitter removing means for compensating for the hysteresis of a pulse generated when the motor is inverted. The present invention relates to a method and apparatus for compensating a pulse hysteresis of a circuit and a medium in which the procedure is recorded as a computer program.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of an apparatus showing a conventional position detecting method of an encoder using a jitter removing circuit. In all the drawings, the same reference numerals indicate the same or corresponding members. FIG. 4 is a logic circuit diagram showing a circuit configuration of the jitter removing circuit. Due to the rotation of the motor 1, two phases having different phases of 90 degrees output from the encoder 2
The phase pulse is input to the counting unit 4 as a pulse from which the jitter has been removed by the jitter removing circuit 3, and the counting unit 4 counts and outputs the edges of the pulse. The output value was input to a central processing unit (CPU) or a storage device and used for controlling the motor.

However, in such a conventional method,
There is a problem that pulse hysteresis occurs when the motor is reversed. FIG. 5 is a time chart of a voltage waveform showing the pulse hysteresis. In general, the encoder two-phase output pulse during motor reversal is as shown in Fig. 5 (a).
The waveform has jitter at the rising and falling portions of the pulse. Therefore, a jitter removing circuit is inserted. However, since the purpose is to remove the jitter, two sets of pulses output from the jitter removing circuit should be as shown in FIG.

[0004]

However, when the jitter elimination circuit shown in FIG. 4 is used, a two-phase output pulse output is as shown in FIG. These figures 5 (b),
As is apparent from FIG. 5C, in the encoder signal processing using the conventional jitter elimination circuit, the first B-phase rising after the motor inversion shown in FIG. The pulse output shown in FIG. 5 (c) shows where the B phase should rise, and the output B phase shown in FIG. 5 (c) rises at the rise of the phase A shown in FIG. 5 (b) [FIG.
52]. In other words, the first count is output to the control device or the like for the first time after the first reversal of the motor.
It can be seen that there is hysteresis here. Therefore, an object of the present invention is to compensate for this hysteresis.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, two-phase rectangular wave signals having phases different from each other by 90 degrees with respect to a displacement of a detection object are output. An encoder for removing jitter generated before an edge of the rectangular wave signal, wherein the two-phase rectangular wave signal and an inverted signal of the rectangular wave signal are input signals of four sets of RS flip-flops; An AND signal of the outputs of the two RS flip-flops out of the outputs of the four RS flip-flops is taken, and the AND signal of the outputs of two other RS flip-flops different from the two RS flip-flops is taken. Accordingly, in the signal processing circuit of the encoder that outputs two-phase rectangular wave signals having a 90-degree phase different from each other and having no jitter at the edge portion, the two-phase rectangular wave output from the signal processing circuit is output. The edge of the wave signal is counted, and when it is determined that the sign of the difference between the count value and the stored previous count value has changed due to the inversion of the motor, the count value is incremented by +1 according to the sign of the difference. Alternatively, it is a pulse hysteresis compensation method for a jitter removing circuit, characterized by adding -1 and outputting. As described above, according to the invention of claim 1 of the present invention, it is possible to compensate for the pulse hysteresis generated when the motor is inverted, and to perform accurate operation without offset when the rotation of the motor is inverted and the motor is repeatedly operated. It has a special effect that it can be stopped at the position.

According to a second aspect of the present invention, there is provided a pulse hysteresis compensation method for a jitter removing circuit according to the first aspect,
The difference between the current counter value and the previous stored value is obtained, and it is determined whether the difference is zero. If the difference is zero, the current counter value is set as the stored value and no correction is performed. The operation of taking the difference is repeated, and if the difference is not zero, it is determined whether or not the sign is different from the previous difference. If the sign is different, +1 or −1 is set as the correction amount according to the sign of the difference. 2. A pulse hysteresis compensation method for a jitter elimination circuit according to claim 1, wherein an output of the encoder is given to the current counter value.

According to a third aspect of the present invention, an encoder which outputs two-phase rectangular wave signals having phases different from each other by 90 degrees with respect to a displacement of a detection object occurs before an edge of the rectangular wave signal. A circuit for removing jitter, wherein the two-phase rectangular wave signal and an inverted signal of the rectangular wave signal are converted into four sets of RS signals.
As an input signal of a flip-flop, a logical product signal of outputs of two sets of RS flip-flops among outputs of the four sets of RS flip-flops is taken, and another two sets of RS flip-flops different from the two sets of RS flip-flops In a signal processing circuit of an encoder which outputs a two-phase rectangular wave signal having a 90 ° phase difference without jitter at the edge portion by taking a logical product signal of the outputs of the amplifiers, the output of the signal processing circuit Means for counting the edges of the phase rectangular wave signal, and when it is determined that the sign of the difference between the count value and the stored previous count value has changed due to the inversion of the motor, the count value is compared with the count value. Means for adding +1 or -1 according to the sign and outputting the added signal. .

According to a fourth aspect of the present invention, an encoder which outputs two-phase rectangular wave signals having phases different from each other by 90 degrees with respect to a displacement of a detection object occurs before an edge of the rectangular wave signal. A circuit for removing jitter, wherein the two-phase rectangular wave signal and an inverted signal of the rectangular wave signal are converted into four sets of RS signals.
As an input signal of a flip-flop, a logical product signal of outputs of two sets of RS flip-flops among outputs of the four sets of RS flip-flops is taken, and another two sets of RS flip-flops different from the two sets of RS flip-flops In a signal processing circuit of an encoder which outputs a two-phase rectangular wave signal having a 90 ° phase difference without jitter at the edge portion by taking a logical product signal of the outputs of the amplifiers, the output of the signal processing circuit Count the edges of the phase square wave signal, and when it is determined that the sign of the difference between the count value and the stored previous count value has changed due to the inversion of the motor, the sign of the difference is added to the count value. A pulse history of a jitter removing circuit, wherein a procedure for adding +1 or -1 according to the output is recorded as a computer program. Reshisu a procedure recorded medium as computer programs of the compensation method.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration according to an embodiment of the present invention. This FIG. 1 is different from the conventional example in FIG. 3 in that the count storage unit 5 and the hysteresis compensating unit 6
Is an additional arrangement.

FIG. 2 is a flowchart showing the operation procedure of the compensation method in the arithmetic unit according to the present invention. 1 and 2 will be described according to the procedure. [1] The motor 1 rotates, and two-phase pulses having a phase difference of 90 degrees are output from the encoder 2 in accordance with the displacement, and the jitter removing unit 3 eliminates the rising and falling portions of the pulse. [2] The counting section 4 detects the rising and falling edges of the pulse from which the jitter has been removed, and also detects the direction of the two-phase pulse, thereby increasing or decreasing the count. Up to this point, it is the same as the conventional example. [3] The storage unit 5 holds the value previously output from the counting unit 4. The value of the storage unit 5 is updated because
This is after the elapse of a certain time or when the output of the counting unit 4 is updated.

[4] In step 21, the compensation calculation unit 6 subtracts the previous value of the count output output from the storage unit 5 from the value currently output from the count unit 4 to obtain a difference. In step 22, if the difference is zero (Ye
s) Return to step 21, and if not zero (No), proceed to next step 23. In step 23, if the sign of the difference is different from the previous one, that is, if the motor 1 is reversed (Yes), go to step 25, if it is the same as the sign of the previous difference (No), If the rotation direction has not changed, the process proceeds to step 24. In step 24, the current difference value is stored as the previous difference value. Further, the correction value is set to zero, and the routine proceeds to step 26. As step 25, the motor 1
Is inverted, so if the current difference value is positive, +1;
If negative, -1 is set as the correction amount, and the routine proceeds to step 26. Further, the present difference value is stored as the previous difference value [as shown in the figure, the difference code multiplied by 1 is used as the correction amount]. In step 26, the counter unit 4
And outputs a value obtained by adding a correction amount to the output.

In this way, when the second edge after the reversal of the motor 1 (see 51 in FIG. 5) is input to the counter section 4, it is output with correction and used for control and the like. Further, it is a matter of course that the operating procedure of the present invention may be described as a computer program, and the computer that reads the program may function as the hysteresis compensating unit 6.

[0013]

As described above, according to the present invention, it is possible to compensate for the pulse hysteresis that occurs when the motor is inverted, and to accurately perform the operation without offset when the motor is inverted and the operation is repeatedly performed. It has a special effect that it can be stopped at an appropriate position.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure of a compensation method in a calculation unit according to the present invention.

FIG. 3 is a block diagram of an apparatus showing a position detection method of an encoder using a jitter removal circuit as a conventional example.

FIG. 4 is a logic circuit diagram showing a circuit configuration of the jitter removing circuit of FIG. 3;

FIG. 5 is a time chart of a voltage waveform showing pulse hysteresis of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Encoder 3 Jitter removal part 4 Count part 5 Storage part 6 Compensation calculation part

Claims (4)

[Claims] 1. With respect to the displacement of a detection object, 90
What is claimed is: 1. A circuit for removing a jitter generated before an edge of a rectangular wave signal of an encoder for outputting a two-phase rectangular wave signal having a different phase, wherein said two-phase rectangular wave signal and an inverted signal of said square wave signal Are input signals of four sets of RS flip-flops, and an AND signal of outputs of two sets of RS flip-flops among the outputs of the four sets of RS flip-flops is obtained. 2
A signal processing circuit of an encoder that outputs a two-phase rectangular wave signal having a 90-degree phase different from the RS flip-flops by 90 degrees and having no jitter at the edge portion by taking a logical product signal of the pair of RS flip-flops; The edges of the output two-phase rectangular wave signal are counted, and when it is determined that the sign of the difference between the count value and the stored previous count value has changed due to inversion of the motor, the count value A pulse hysteresis compensation method for a jitter removing circuit, wherein +1 or -1 is added according to the sign of the difference and output. 2. A pulse hysteresis compensation method for a jitter removing circuit according to claim 1, wherein a difference between a current counter value and a previous stored value is obtained, and it is determined whether or not the difference is zero. The operation of obtaining the difference from the next counter value is repeated without performing the correction by making the counter value of the stored value into the stored value, and if the difference is not zero, it is determined whether or not the sign is different from the previous difference. Are different, +1 or -1 depending on the sign of the difference
2. The pulse hysteresis compensation method for a jitter elimination circuit according to claim 1, wherein the correction value is given as the correction amount to the current counter value to obtain an output of the encoder. 3. Displacement of the detection object is 90
What is claimed is: 1. A circuit for removing a jitter generated before an edge of a rectangular wave signal of an encoder for outputting a two-phase rectangular wave signal having a different phase, wherein said two-phase rectangular wave signal and an inverted signal of said square wave signal Are the input signals of the four sets of RS flip-flops, and of the outputs of the four sets of RS flip-flops, the logical product signal of the outputs of the two sets of RS flip-flops is taken. 2
A signal processing circuit of an encoder that outputs a two-phase rectangular wave signal having a 90-degree phase different from the RS flip-flops by 90 degrees and having no jitter at the edge portion by taking a logical product signal of the pair of RS flip-flops; Means for counting edges of a two-phase rectangular wave signal as an output; and when it is determined that the sign of the difference between the count value and the stored previous count value has changed due to inversion of the motor, the count value And a means for adding +1 or -1 according to the sign of the difference and outputting the result. 4. With respect to the displacement of the detection object, 90
What is claimed is: 1. A circuit for removing a jitter generated before an edge of a rectangular wave signal of an encoder for outputting a two-phase rectangular wave signal having a different phase, wherein said two-phase rectangular wave signal and an inverted signal of said square wave signal Are the input signals of the four sets of RS flip-flops, and of the outputs of the four sets of RS flip-flops, the logical product signal of the outputs of the two sets of RS flip-flops is taken. 2
A signal processing circuit of an encoder that outputs a two-phase rectangular wave signal having a 90-degree phase different from the RS flip-flops by 90 degrees and having no jitter at the edge portion by taking a logical product signal of the pair of RS flip-flops; The edges of the output two-phase rectangular wave signal are counted, and when it is determined that the sign of the difference between the count value and the stored previous count value has changed due to inversion of the motor, the count value A medium in which a procedure of a pulse hysteresis compensation method of a jitter removing circuit is recorded as a computer program, wherein a procedure of adding +1 or -1 according to the sign of the difference and outputting the result is recorded as a computer program.