JPS59116551A - Speed signal detector - Google Patents

Abstract

PURPOSE:To reduce ripple of a speed signal while improving the response with the removal of high frequency components by differentiating and then differentiating and inverting outputs in two phases as input of a double phase type rotary encoder to be converted into four signals to synthesize them trimming near the maximum or the minimum thereof. CONSTITUTION:Outputs of a double phase type rotary encoder are supplied into input terminals 1a and 1b and in the normal rotation, A0 advances by 90 deg. with respect to B0. The outputs are respectively differentiated with differentiation circuits 2 and 3. They are inverted with inversion circuits 4 and 5 and outputs thereof A1, B1 and -A1 and -B1 are supplied to an analog switch 6. Inputs A0 and B0 are added with an addition circuit 7 and the input A0 inverted with an inversion circuit 9 is added to the input B0 with an addition circuit 8. Then, outputs C1 and C2 are converted into a pulse by identifying a code with pulse conversion circuits 10 and 11 and a binary counter 12 has four outputs of S1-S4. The outputs are trimmed and synthesized when each high level comes out to produce an output V1. An output of the analog switch 6 is treated with an LPF 13 to remove high frequency components.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a speed signal detection device used as a speed sensor for a power source that requires speed control, such as a machine tool or a robot.

(Conventional configuration and its problems) Generally, in a servo system that performs mechanical control of an industrial robot or the like, a velocity loop is required to stabilize the system's operation and improve responsiveness. Therefore, conventionally, a DC tough generator was installed as a speed signal detector to detect the speed signal. However, since DC tachogenerators have rectifying brushes, maintenance and inspection are required and handling is complicated. Further, in a servo system that performs positioning control, it is necessary to also install a rotary encoder or the like for detecting a position signal, which makes the system expensive.

Other conventional speed signal detection devices obtain speed signals by f/υ conversion of the pulse output of a low-resolution encoder for detecting position signals, but in this case, in speed control with a large speed change range, the response Increasing the performance caused the ripples at speed 48 to become thicker at low speeds, and smoothing and reducing the ripples at low speeds resulted in poor responsiveness.

(Object of the invention) The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and
It is an object of the present invention to provide a speed signal detection device which has less ripples in a detected speed signal, has good responsiveness, and is inexpensive.

(Structure of the Invention) In order to achieve the above object, the present invention inputs the two-phase output of a two-phase O-cli encoder, differentiates and inverts the two-phase human power of In a switching circuit, the vicinity of the maximum or minimum value of each of the four signals is trimmed and synthesized according to the signal obtained by calculating and logically processing the two-phase input. It is designed to remove components.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, where 1a and 1b are input terminals to which the output of a two-phase rotary encoder is supplied, 2 and 3 are differentiating circuits, and 4
and 5 are inverting circuits, 6 is an analog switch,
7 and 8 are adder circuits, 9 is an inversion circuit, JO and 11 are pulse conversion circuits, 12 is a binary counter, and 13 is a low-pass filter.

Next, the operation of this embodiment during forward rotation will be explained with reference to FIG. 2(A) showing the output waveforms of each part. The output of a two-phase rotary encoder that outputs a two-phase sine wave (square or triangular wave) having a constant amplitude and a phase difference of 90° from each other is supplied to input terminals 1a and 1b.
and 150 inputs are respectively AO and 130, then in the case of forward rotation, A.

is ahead of Bo by 900 phases. This input A.

and B. are differentiated by differentiating circuits 2 and 3, and the outputs are respectively A1 and B1, and AI and B1 are further inverted by inverting circuits 1 and 5, respectively, and the outputs are A and 1, and these outputs AI .

Bl + AI and B1 are supplied to analog switch 6. In addition, the human power Ao and Bo are added by adding circuit 7.
The output is set as C1, and the input Ao is inverted by the inverting circuit 9. The fc signal and the input Bo are added by the booster circuit 8, and the output is set as C2. Then, C1 and C2 are converted into cibars by determining the signs in pulse conversion circuits 1o and jl, respectively, and their output is expressed as D and B2, respectively.
The signal is supplied to the binary counter 12 as follows. The binary counter 12 is s, l B2 p B3 and B4.
The pulse conversion circuit has one output, and outputs DJ and B2 of ]0 and "1 are input, and the logic Q I
According to f, when both Dl and B2 are low, the output S] is high; when Dl is high and B2 is low, the output S2 is high;
When both DI and B2 are high, the output S3 is high, and when DI is a- and B2 is high, the output S1 is high, and these outputs are supplied to the analog switch 6. Here, the analog switch 6 outputs each output AI*Blp of the differential/divider circuits 2 and 3 and the inverting circuits 4 and 5.
Al and 11 are supplied, and the outputs of binary counter 12 "'I, S2+" 3 and B4,
A1 is trimmed at 81, B1 is 82, A is trimmed at each high output, B1 is trimmed at each high output of B4, and the output is synthesized and output v
Outputs 1. A low-pass filter 13 removes high-frequency components from the output of the analog switch 6 to obtain a ripple-free output V(,) proportional to the rotational speed.

Here, inputs A and B are shown in the second figure).

The output C] is delayed in phase by 45 degrees with respect to the input Aoi/i, and therefore the output D1 of the pulse conversion circuit 10 is also delayed in phase by 45 degrees with respect to the input AO. There is. Similarly, the output D of the pulse conversion circuit 11
2 also has a 45° phase delay with respect to input Bo and a 90° phase delay with respect to DJ. Therefore, the outputs of the binary counter 12 SJ h , , B2 y ""3 and s
4 is 900 respectively from 81 to 84 during -period jυ''
A high output is generated sequentially for each period, and SI has a 45° phase lead with respect to AQ. At this time, the differential circuit 2
The outputs A1 and 131 of : and 3 are inputs A and B.

Since the phase is advanced by 90° with respect to each other, AI r Bl , A1 and B1 are set to 1. The IJ minking position is within a range of ±45° with respect to the Jv maximum value of each sine wave. Therefore,
By combining four outputs with only the vicinity of the maximum value trimmed, a positive DC voltage v1 proportional to the rotation speed with good responsiveness and less ripple can be obtained from the AC voltage proportional to the rotation speed. Although this Vl has little ripple, it includes about 30% of the nozzle voltage. Therefore, a two-phase rotary encoder generates several hundred to several thousand pulses per revolution, and the frequency of its outputs AO and B is several hundred to several thousand times the number of rotations of a two-phase one-crystal encoder. Moreover, the ripple frequency &′ of V: LAo and B. The ripple voltage can be easily removed using the low-pass filter [3] without impairing the response.

However, if the rotation direction of the two-phase rotary encoder changes to the opposite direction, the output AO and phase of the output BQ will change to A.
90° with respect to Q, and in this embodiment, as shown in FIG. As the position changes and trimming is performed around each minimum value, in the case of forward rotation, a positive voltage was output, but in the case of reverse rotation, a negative voltage is output, and the voltage changes depending on the direction of rotation. V configured such that the polarity of the output voltage changes;
Ru.

Note that this embodiment has similar effects even when the output of the two-phase rotary encoder is a triangular wave.

(Effects of the Invention) As explained above, the present invention uses the output of a two-phase rotary encoder as an input, and generates a ripple-free and responsive DC voltage that differs in polarity depending on the rotational direction and is proportional to the rotational speed. can be detected. Further, in the servo system used for positioning control, since a DC generator is not required, there is no need for maintenance and inspection, and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the configuration of an embodiment of the present invention;
FIG. 2 is a diagram showing the output θ curves of each part in FIG. 1. 2.3... Differential circuit, 6+ 5+ 9...
Inverting circuit, 6... -Anna "j guess inch, 7,8
...Addition circuit, 10.11 ...Pulse conversion circuit, 12-mountain binary counter, 33...
・Low pass filter. Special Applicant Matsushita Electric Industrial Co., Ltd. Vo oH-11111-2 Diagram B1 Vo-111 procedural amendment (voluntary) Revenue stamp L (K11 yen January 6, 1980 q) ° Compilation of Director-General Kazuo Wakasugi 1, Indication of the case Patent Application No. 1987-225'120 3, Relationship with the case of the person making the amendment Exit, ;□''゛1 person address
Osaka R'N Kadoma City Ote Kadoma] 006 number two names each
(sa2) Matsushita 1L2-Industry) Song Ren Company Dai 1. ．． Name Shun Yamashita Ima4
, Agent 〒105 (1 location 11-1.1 Shin 1iffia J, Minato-ku, Tokyo)
Month 3 No. 3 No. 5, Supplement 11: The number of inventions increases due to
0(2) Delete "(or triangular wave)" on page 4, line 18 of the specification. (3) “Triangular wave” on page 8, line 12 to line 13
Add "pseudo sine wave lta (-)" in front of . (4) Correct "DC generator" in the first line of page 9 to "DC Takojay Sinter". Above two "I' + i';,,l'I ice/l) 4-line J-4 special + j'F Jl-specified range Jl 4Ji 1-phase IT-1 string with a constant value and a phase difference of 900 from each other The input is the output of a two-phase low-resolution encoder that outputs a sine wave, a sine wave, and a triangular wave. a differentiating circuit, first and second inverting circuits that invert the outputs of the first and second differentiating circuits, respectively, a first adding circuit that adds the two phases of human power indicated by i'lj; A second adder circuit that inverts two-phase human power using an inverter circuit and then adds it, and a theory that sequentially outputs four types of outputs during one cycle using the outputs of the first and second adder circuits. 111 first and second differentiating circuits by the outputs of the circuit and the four buckets of the AiJ logic circuit.
f) A switching circuit that performs reminogging and synthesis of the maximum or minimum value of each output 2 of the first and second inverting circuits, and a filter that removes high frequency components of the output of the switching circuit. A speed signal detection device comprising a circuit, and detects a DC voltage whose polarity differs depending on the rotation direction (l) and is proportional to the rotation speed from the output of the two-phase rotary encoder.

Claims (1)

[Claims] The output of a two-phase rotary encoder that outputs a two-phase triangular wave or a sine wave with constant amplitudes 111' and 4 and a phase difference of [90' from each other is input, and the two-phase inputs are differentiated. first and second differentiating circuits, first and second inverting circuits that invert the outputs of the first and second differentiating circuits, respectively, and a first adding circuit that adds the two-phase inputs; A second adder circuit inverts only one phase of the two-phase inputs using an inverter circuit, and then adds the two-phase inputs, and outputs from the first and second adder circuits produce four types of outputs during one cycle. According to the output logic circuit and the four types of outputs of the logic circuit, the vicinity of the maximum value or minimum value of each output of the first and second differentiating circuits and the seventeenth and second inverting circuits is trimmed, respectively. and a filter circuit that removes high-frequency components from the output of the switching circuit, and a DC current whose polarity differs depending on the rotational direction and which is proportional to the rotational speed from the output of the two-phase rotary encoder. A speed signal detection device characterized by detecting voltage.