JPH01219672A - Pulse converter circuit - Google Patents

Abstract

PURPOSE:To obtain a highly precise pulse conversion output, by removing a normal rotation pulse and a reverse rotation pulse from a gradual multiplication circuit at the time when a normal or reverse rotation detected by a rotation change detecting circuit changes. CONSTITUTION:An inversion detection pulse (f) is inputted to the other end of an AND gate 10 through NOT, and therefore reverse rotation pulses C1 and C3 are removed at the times t1 and t3 when a motor M is inverted from a normal rotation to a reverse rotation. At the time t2 when the motor M is inverted from the reverse rotation to the normal, a normal rotation pulse C2 is removed. As the result, one pulse at the instance of the inversion of rotation of the motor M is removed from a speed detection pulse P. Based on the reception of each of normal and reverse rotation pulses cw and ccw, in this way, a rotation direction signal (q) is outputted, while the time of change of the normal or reverse rotation of the motor M is detected from the signal (q), one pulse of each of the pulses cw and ccw is removed at this time of change, and thereby the speed detection pulse P is obtained. Accordingly, no false detection of the speed detection pulse takes place, even when one pulse is generated with the generation of vibration at the time of inversion of the motor M.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a pulse conversion circuit that multiplies a signal from an encoder by n and converts it into a speed detection pulse.

(Prior Art) There are two types of encoders: absolute type and incremental type. Of these, the incremental type outputs A-phase and B-phase pulse signals having a phase difference of 90° from each other. When detecting, for example, the rotational speed or rotational position of a motor from each pulse signal output from such an encoder, each pulse signal from the encoder is converted into, for example, forward rotation pulses and reverse rotation pulses through a quadrupling circuit, and finally these pulses are converted into forward rotation pulses and reverse rotation pulses. It is output as a speed detection pulse that is a combination of pulses. Regarding the rotation direction of the motor, the phase of one of the A-phase and B-phase signals is output regardless of whether the motor is in the forward or reverse direction, and the phase of the other signal is reversed by 180 degrees when the motor is reversed. It is detected because of this.

Therefore, when controlling the speed of the motor, the rotational speed of the motor is determined by counting the speed detection pulses, and the rotational speed of the motor is adjusted to a desired speed based on this rotational speed.

However, if the speed detection pulses are obtained by the method described above, the speed detection pulses will be output continuously even when the rotational direction of the motor is reversed. When the speed detection pulses are generated continuously in this way, the speed detection pulses are also generated at the moment when the motor reverses.

However, if vibration occurs in the motor at the moment of rotation reversal of the motor, one pulse will be generated due to this vibration. In this case, especially if this vibration has a high frequency, the motor will be detected as if it were rotating even though it has stopped rotating.

(Problems to be Solved by the Invention) As described above, when vibration occurs in the motor, for example, when the motor is reversed, one pulse may be generated due to the vibration, and the rotational speed of the motor may be erroneously detected.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a pulse conversion circuit that can obtain speed detection pulses and the like with high accuracy even when a motor or the like is reversed.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a pulse conversion circuit that converts two signals outputted from an encoder and having a predetermined phase difference from each other into at least speed detection pulses. A multiplier circuit that multiplies each signal by n and converts it into forward rotation pulses and reverse rotation pulses, and outputs the same; and a rotation direction output that receives the forward rotation pulses and reverse rotation pulses from this multiplication circuit and outputs a rotation direction signal indicating the rotation direction. a rotation change detection circuit that receives a rotation direction signal from this rotation direction output circuit and detects a change in forward/reverse rotation, and a rotation change detection circuit that detects a change in forward/reverse rotation detected by this rotation change detection circuit; This is a pulse conversion circuit that attempts to achieve the above object by including a pulse removal circuit that removes pulses and reverse pulses.

The present invention also provides a delay circuit for delaying and outputting a rotation direction signal by a time corresponding to each pulse width of a forward rotation pulse and a reverse rotation pulse, and a delayed output signal from the delay circuit and the rotation direction signal for the rotation change detection circuit. This is a pulse conversion circuit configured with an EXOR gate that performs exclusive OR with a signal and outputs an inversion detection pulse.

(Function) By providing such a means, the rotation direction output circuit receives the forward rotation pulse and the reverse rotation pulse from the multiplier circuit and outputs a rotation direction signal indicating the rotation direction, and the rotation change detection circuit outputs a rotation direction signal indicating the rotation direction. It receives the rotation direction signal from the output circuit and detects when there is a change in forward or reverse rotation. Thus, the pulse removal circuit removes the forward rotation pulse and reverse rotation pulse from the multiplier circuit when the rotation change is detected by the rotation change detection circuit, and outputs the removed pulse as a speed detection pulse.

In addition, the rotational change detection circuit at this time outputs the rotational direction signal delayed by a time corresponding to each pulse width of the forward rotation pulse and the reverse rotation pulse by the delay circuit, and EXORs this delayed output signal and the rotational direction pulse. Obtain an inverted detection pulse by passing it through the gate.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram of the pulse conversion circuit.

In the figure, reference numeral 1 denotes a pulse conversion circuit, which includes a quadrupling circuit 3 that receives A-phase and B-phase pulse signals a and b output from an encoder 2 and having a phase difference of 90' from each other. . Note that the encoder 2 is connected to the rotating shaft of a motor M that drives the shaft of the manipulator F. This quadrupling circuit 3 receives the clock signal elk and multiplies each pulse signal a, b by four to produce a forward rotation pulse CV and a reverse rotation pulse C.
It has a function to output as CW. Forward rotation pulse Cν and reverse rotation pulse CCW output from this quadrupling circuit 3
are both sent to the RS flip-flop 4 as a rotational direction output circuit, and these pulses cv,
Of the ccv, the forward rotation pulse CV is applied to the S input terminal, and the reverse rotation pulse CCV is applied to the R input terminal. A rotation direction signal q is output from the Q output terminal of this RS flip-flop 4.

Reference numeral 5 denotes a rotational change detection circuit, and this circuit 5 has a function of receiving the rotational direction signal q and detecting when the motor M changes between forward and reverse directions.
A forward rotation pulse CW and a reverse rotation pulse Ceν are received at the input terminal.
It consists of a D flip-flop 6 which outputs a delayed output by the same time as the pulse width, and an EXOR gate 7 which performs the exclusive OR of the delayed signal q' from the Q output terminal of this flip-flop 6 and the rotation direction signal q. There is. Note that the clock signal c1k is input to the D flip-flop 6,
Further, the output of the EXOR gate 7 becomes the inversion detection pulse f.

On the other hand, 8 is a pulse removal circuit, and this circuit 8 receives a reversal detection pulse f, and when the motor M is reversed, a forward rotation pulse C is generated.
It has a function of removing one pulse of V and reverse pulse CCν. Specifically, an OR gate 9 performs the logical sum of the forward rotation pulse CV and the reverse rotation pulse CaW, and an AN performs the logical product of the output of this gate 9 and the reversal detection pulse f.
D gate 10. Thus, this A
The output of the ND gate 10 is output as a speed detection pulse P, and the inverted detection pulse f passes through a NOTOR gate 9, so that it is output as an inverted detection pulse R whose level is inverted. These speed detection pulses P and inversion detection signal R are sent to a control device 12, and this control circuit 12 counts the speed detection pulses P to find the rotational speed of the motor M, and calculates the rotational speed of the motor M. It has a function of sending a rotation control signal ss to the motor M according to the difference from the set speed to control the rotation of the motor M at the set speed.

Next, the operation of the circuit configured as described above will be explained with reference to the operation timing chart shown in FIG. Control device 1
When the rotation control signal ss is sent from the encoder 2 to the motor M and the motor M is driven, the encoder 2 outputs pulse signals a and b having a phase difference corresponding to the rotation speed and rotation direction of the motor M. The quadrupling circuit 3 receives these pulse signals a and b, multiplies them by four, and outputs them as forward rotation pulses CV and reverse rotation pulses CCV. At this time, as shown in FIG. 2, if the motor M is rotating in the normal direction, a normal rotation pulse cv will appear, and if it is in the reverse rotation, only the reverse rotation pulse CCV will appear. Both of these pulses cw and ccv are sent to the RS flip-flop 4, but when the normal rotation pulse Cν is applied to the S input terminal of this flip-flop 4, a high-level rotation direction signal q, that is, is sent from the Q output terminal of the flip-flop 4. A rotation direction signal q indicating forward rotation is output, and when a reverse rotation pulse CCV is applied to the S input terminal, a low level rotation direction signal q, that is, a rotation direction signal q indicating reverse rotation, is output from the Q output terminal. . Since this rotation direction signal q is applied to the D input terminal of the D flip-flop 6, the forward rotation pulse CV and the reverse rotation pulse CCV are output from the Q output terminal of the D flip-flop 6.
A rotational direction signal q' delayed by a time equal to the pulse width of is output. As a result, this rotational direction signal q'' and the rotational direction signal q are sent to the EXOR gate 7, and this gate 7 outputs the reversal detection pulse f of the motor M. Note that this reversal detection pulse f is positive. It is a low level signal having the same pulse width as the rotation pulse CV and the rotation pulse Ceν.

On the other hand, at this time, the forward rotation pulse CV and the reverse rotation pulse CCV outputted from the quadrupling circuit 3 are each passed through an OR gate 9, combined, and sent to one end of an AND gate 10. Since the reversal detection pulse f is input through the knot to the other end of the AND gate 10, the reversal pulses c1 and c3 are removed at times t1 and t3 when the motor M reverses from normal rotation to reverse rotation. Further, at time t2 when the motor M reverses from reverse to normal rotation, the normal rotation pulse c2 is removed. As a result, the speed detection pulse P is obtained by removing one pulse at the moment when the rotation of the motor M is reversed.

In this way, in the above-described embodiment, upon receiving the forward rotation pulse Cν and the reverse rotation pulse CCV, the rotation direction signal q indicating the rotation direction is outputted, and the time of change between forward and reverse rotation of the motor M is detected from this rotation direction signal q. , Since the speed detection pulse P is obtained by removing one pulse of the forward rotation pulse cv and the reverse rotation pulse CCV during this forward/reverse change, even if one pulse is generated due to vibration when the motor M is reversed, , this one pulse prevents the speed detection pulse from being erroneously detected when the motor is reversed. Furthermore, the control device 12
If the reversal detection pulse R is used as a counter clear signal for the speed detection pulse P, the speed can be detected with high accuracy after the motor is reversed. Furthermore, when the motor M is forcibly stopped, the forward rotation pulse CV and the reverse rotation pulse CCν may be output alternately. It can be detected that M is stopped.

Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof. For example, other circuits may be used instead of the D flip-flop 6 as a circuit for delaying the rotational direction signal q. Further, the multiplication number of the quadrupling circuit may be set to another number for multiplication.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a pulse conversion circuit that can obtain speed detection pulses and the like with high accuracy even when a motor or the like is reversed.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of a pulse conversion circuit according to the present invention, and FIG. 2 is an operation timing diagram of the same circuit. 1...Pulse conversion circuit, 2...Encoder, 3...
・Quadruple multiplier circuit, 4...RS flip-flop, 5...
・Rotation direction output circuit, 6...D flip-flop, 7
...EXOR gate, 8...pulse removal circuit, 9.
...OR gate, 10...AND gate, 12...
Control device, M...motor, F...manipulator. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) In a pulse conversion circuit that converts two signals outputted from an encoder with a predetermined phase difference from each other into at least speed detection pulses, each signal from the encoder is multiplied by n and converted into forward rotation pulses and reverse rotation pulses. A multiplier circuit that converts and outputs a rotational direction signal, a rotational direction output circuit that receives forward rotation pulses and reverse rotational pulses from this multiplier circuit and outputs a rotational direction signal indicating the rotational direction, and a rotational direction signal from this rotational direction output circuit. and a pulse removal circuit that removes the forward rotation pulse and the reverse rotation pulse from the multiplier circuit when the rotation change detection circuit detects a change in forward and reverse rotation detected by the rotation change detection circuit. A pulse conversion circuit characterized by: (2) The rotation change detection circuit includes a delay circuit that delays and outputs a rotation direction signal by a time corresponding to each pulse width of a forward rotation pulse and a reverse rotation pulse, and a delay output signal from this delay circuit and the rotation direction signal. 2. The pulse conversion circuit according to claim 1, wherein the pulse conversion circuit comprises an EXOR gate that performs an exclusive OR, and outputs an inversion detection pulse having the same width as each of the forward rotation pulse and the reverse rotation pulse.