JPH02195262A - Apparatus for detecting speed signal - Google Patents

Abstract

PURPOSE:To output sufficiently smoothed speed signal at an extremely low speed and fully cope with high speed and high resolution by outputting speed signals while switching over low speed and high speed. CONSTITUTION:A divider-circuit 6 divides a pulse signal P1 from a signal processing circuit 2 to output a pulse signal P2. A changeover switch 7 outputs the pulse signal P1 as a pulse signal P3 when speed of a driving source connected to a rotary encoder 1 is low and outputs the pulse signal P2 as the pulse signal P3 when the speed is high. A one-shot multi-oscillation circuit 8 for receiving this pulse signal P3 converts it into a pulse signal P4 having pulse width T2 and outputs it. An F/V conversion circuit 9 for receiving the pulse signal P4 converts the pulse sequence into speed signal S1 proportional to the number of pulses per certain time period. A polarity giving circuit 10 for receiving the speed signal S1 and rotation direction signal N reverses the polarity of the speed signal S1 according to the signal N to output it as speed signal S2.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a speed signal detection device that detects the dynamic characteristics of a digital servo system that drives a machine tool or robot from the output signal of a rotary encoder of the system. .

(Prior Art) An example of the configuration of a conventional speed signal detection device is shown in FIG. 3, and its operating principle will be explained below.

A with a 90" phase difference, which is the output of the rotary encoder (RE) 1 directly connected to the drive source of the digital servo system.
The signal processing circuit 2, which receives the phase signal and the B-phase signal as input, converts each edge of the A-phase signal and the B-phase signal into a pulse with a constant time width T, and generates a pulse signal P1, and the A-phase signal and the B-phase signal. The rotational direction is detected from the phase of , and the rotational direction N is output.

The voltage conversion circuit 3, which receives the rotation direction signal N, makes the power supply voltage of the pulse conversion circuit 4 positive when the rotation direction signal N8 is high, and makes the power supply voltage of the pulse conversion circuit 4 positive when the rotation direction signal N8 is low. The power supply voltage is converted into a negative rotation direction signal N2. The pulse conversion circuit 4 is composed of a 3-state IC, and the pulse signal P1 is input to the control terminal (C), and the one rotation direction signal N2 is connected to the input port (I), so that the pulse signal is output to the output port (0). While P1 is high, the voltage at the input port is output, and while P1 is low, the impedance is high and the output voltage is zero.

The power supply of the pulse conversion circuit 4 is composed of a positive power supply and a negative power supply having the same absolute value. As a result, the output of the pulse conversion circuit 4 has a polarity that differs by one in the rotational direction.

A pulse signal P having a pulse width T is obtained. Pulse signal P2
The integrating circuit 5, which receives as input, integrates the pulse signal P2 to output a smoothed speed signal S that is proportional to the speed of the drive source of the digital servo system.

(Problems to be Solved by the Invention) In the conventional configuration described above, the following drawbacks occur when attempting to achieve high speed and high resolution.

Increasing the speed and resolution requires increasing the response frequency of the signal processing circuit 2 and decreasing the pulse width T of the pulse signal P□. Therefore, it is difficult to configure the pulse conversion circuit 4 with three state controllers.

Furthermore, there is a problem that a sufficiently smooth speed signal S cannot be obtained at extremely low speeds.

(Means for solving problems) The present invention aims to solve the above problems.

A signal processing circuit that converts the 1-rotation direction signal N and the pulse edge of each phase into a pulse signal P4 with a constant time width T1 from the A-phase signal and B-phase signal with 90° different phases of the rotary encoder directly connected to the drive source of the digital servo system. , a frequency dividing circuit that outputs a pulse signal P2 whose frequency is divided by 1/n of the pulse signal P, and a pulse signal P8 in the case of low speed,
For high speed, select pulse signal P,
a one-shot multi-oscillator circuit that converts the pulse signal P3 into a pulse signal P with a constant time width T2, and a one-shot multi-oscillation circuit that converts the pulse signal P4 into a speed signal S.
1, and a polarization circuit that switches between an inverting amplifier and a non-inverting amplifier with equal amplification factors depending on the rotation direction from the speed signal S1 and the rotation direction signal N to output a speed signal S2. It is characterized by being configured as follows.

(Function) With the above-described configuration, the present invention outputs a speed signal by switching between low speed and high speed, so a sufficiently smooth speed signal can be output even at extremely low speeds, and it can sufficiently cope with high speed and high resolution. .

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the block diagram of FIG. 1 and the polarization circuit of FIG. 2.

Note that the description of the same components as in the conventional example will be omitted.

In FIG. 1, the division circuit 6 receives the pulse signal P from the signal processing circuit 2, divides the number of pulses into 1/n, and outputs the pulse signal P. The changeover switch 7 outputs the pulse signal P1 as a pulse signal P when the speed of the drive source connected to the rotary encoder 1 is low, and outputs the pulse signal P2 as a pulse signal P when the speed is high.

The one-shot multi-oscillation circuit 8 which receives this pulse signal P3 as input converts it into a pulse No. 1 P4 having a pulse width T2 and outputs it.

Further, in the F/V conversion circuit 9 which inputs the pulse signal P4,
A speed signal S that is proportional to the number of pulses per fixed time for a pulse train
A polarization circuit 10, which receives the zero-order speed signal S□ to be converted to 1 and the rotational direction signal N, inverts the polarity of the speed signal Si according to the rotational direction signal N and outputs it as a speed signal S2.

In the polarization circuit 10 shown in FIG. 2, the speed signal S□ is input, and when the rotation direction signal N is high, the operational amplifier 11
By turning on FETI connected to the non-inverting terminal (+) of , and connecting it to the source of FET2 which is already on,
Set the non-inverting terminal (+) to Ov. As a result, the speed signal S8 input to the inverting terminal (-) of the operational amplifier 11 is inputted, inverted and amplified, and the speed signal S2 of the following equation is output.

Speed signal S2 = speed signal S□×-2R, -... (1)
Even if the on-voltage of R1 FETI changes due to temperature, FET2
changes in the same way, so there is little variation in the offset voltage.

Further, when the rotation direction signal N is low, FETI is turned off and the non-inverting terminal (+) of the operational amplifier 11 is turned off.

It has the same potential as the speed signal S1, and the polarization circuit outputs a speed signal S expressed by the following equation.

Speed signal S@=speed signal S1... (2) Then (1)
By setting RL=R as shown in the equation, speed signals with different polarities can be output when the direction of one rotation is different.

(Effects of the Invention) As explained above, according to the present invention, even when high speed and high resolution are achieved, by outputting a speed signal by switching between low speed and high speed, a sufficiently smooth speed signal is output even at extremely low speeds. I can do that.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 2 is a circuit diagram of an embodiment of the polarization circuit shown in FIG. 1, and FIG. 3 is a circuit diagram of a conventional example. DESCRIPTION OF SYMBOLS 1... Rotary encoder, 2... Signal processing circuit, 6... Frequency division circuit, 7... Changeover switch, 8... One-shot multi-oscillation circuit,
9...F/V conversion circuit. 10...Polarization circuit, p,, p,, p,. P4...Pulse signal, N...Rotation direction signal, S
l, S,...Speed signal. Patent applicant Matsushita Electric Industrial Co., Ltd. Figure 2

Claims (2)

[Claims] (1) A signal processing circuit that converts the rotational direction signal N and the pulse edges of each phase into a pulse signal P_1 with a constant time width T_1 from the A-phase signal and B-phase signal of a rotary encoder having 90° different phases, and the pulse signal A frequency dividing circuit that outputs a pulse signal P_2 whose frequency is divided by 1/n of P_1, a pulse signal P_1 when the speed is low, and a pulse signal P when the speed is high.
a selector switch that selects and outputs the pulse signal P_2 as a pulse signal P_3; a one-shot multi-oscillator circuit that converts the pulse signal P_3 into a pulse signal P_4 with a constant time width T_2; and an F that converts the pulse signal P_4 into a speed signal S_1. 1. A speed signal detection device comprising: a /V conversion circuit; and a polarization circuit that converts the speed signal S_1 and the rotation direction signal N into a speed signal S_2 whose polarity changes depending on the rotation direction. (2) The speed signal detection device according to claim (1), wherein the polarization circuit according to item (1) is configured to switch between an inverting amplifier and a non-inverting amplifier having equal amplification factors depending on the direction of rotation.