KR100969582B1 - Method for detecting the position of the Rotor - Google Patents

Abstract

The present invention relates to a precise position detection method of a rotor using two phases (sine wave; A phase, cosine wave; B phase) output from a sine wave encoder, and more particularly, to a slit formed in the rotor of the sine wave encoder. Determining the number, defining the number of sine waves generated in one revolution according to the number of slits of the rotor as r, and defining an angle (360 / r) corresponding to one period of the sine wave as p; Defining a signal of phase A as B and a signal of phase B to generate S1, which is a linear signal, and forming the linear signal S1 within one period of the phase A sine wave according to the signs of As and Bs. Generating a typical signal S2, generating a square wave by comparing the sign of the sine wave on the A phase, and generating S3 which is an absolute position of the rotor by n as the number of rising edges of the square wave; Egg It relates to a precise position detection method of the rotor using the output signal of the sine wave encoder, characterized in that it comprises a mechanism.

Sine wave, encoder, position measurement, sine wave, rotation

Description

Method for detecting precise position of rotor using output signal of sine wave encoder {Method for detecting the position of the Rotor}

The present invention relates to a precise position detection method of a rotor using two phases (sine wave; A phase, cosine wave; B phase) output from a sine wave encoder, and more particularly, to a slit formed in the rotor of the sine wave encoder. Determining the number, defining the number of sine waves generated in one revolution according to the number of slits of the rotor as r, and defining an angle (360 / r) corresponding to one period of the sine wave as p; Defining a signal of phase A as B and a signal of phase B to generate S1, which is a linear signal, and forming the linear signal S1 within one period of the phase A sine wave according to the signs of As and Bs. Generating a typical signal S2, generating a square wave by comparing the sign of the sine wave on the A phase, and generating S3 which is an absolute position of the rotor by n as the number of rising edges of the square wave; Egg It relates to a precise position detection method of the rotor using the output signal of the sine wave encoder, characterized in that it comprises a mechanism.

Conventional printers or multifunction devices include sinusoidal encoders, signal inversion circuits, square wave generation circuits, signal selectors, and analog / digital converters (ie, A / D converters) for position control. The sinusoidal encoder outputs sinusoidal signals with two channels having a phase difference of 90 degrees. The signal inversion circuit inverts the sinusoidal signals output from the sinusoidal encoder. The square wave generation circuit converts analog signals into square waves. The signal selector receives the sinusoidal signals output from the sinusoidal encoder and the inverted sinusoidal signals output from the signal inversion circuit, and selects one of the analog signals input according to the square wave signal output from the square wave generation circuit. The analog / digital converter converts the analog signal output from the signal selector into a digital signal.

However, a conventional position control device having a sinusoidal encoder requires a signal inversion circuit for inverting two channel signals output from the sinusoidal encoder and a signal selector for selecting and outputting analog signals to an analog / digital converter. Therefore, the conventional position control device has a problem in that the accuracy of the position control is not high, while the structure is complicated.

In addition, in the case of a precise position detection method of the rotor using a sinusoidal encoder, an interpolator is required to convert the digital value and obtain a multiplied effect because it is output as an analog value instead of a digital signal output from a general encoder. Since the output signal is an analog value, theoretically, the interpolator can have infinite multipliers, so that the position information of the rotor suitable for the ultra-precision servomotor can be obtained. Interpolators of sine wave encoders are usually used in two types, one of which is a form of sine wave and cosine wave output from sine wave encoder, and using this to output position information according to the input value. Another is a form of outputting position information by arc tangent operation using the values of sine wave and cosine wave input using a processor. The former method has a disadvantage in that the capacity of a memory device such as a ROM is increased because the lookup table increases exponentially with the increase of the multiplication number while the interpolation time is fast. The latter method is easy to implement. On the other hand, the operation time is long and requires a high speed processor.

The present invention has been made to solve the above problems, an object of the present invention is to provide a precise position detection method of the rotor using the output signal of the sine wave encoder can be easily implemented with a short calculation time.

An object of the present invention as described above is a precision position detection method of a rotor using a two-phase (sine wave; A phase, cosine wave; B phase) output from a sine wave encoder, the slit formed in the rotor of the sine wave encoder Determining the number (S10); Defining the number of sine waves generated in one revolution according to the number of slits of the rotor as r, and defining an angle 360 / r corresponding to one period of the sine wave as p (S20); Defining the signal of phase A as B and the signal of phase B as Bs and thereby generating a linear signal S1 (S30); Generating a linear signal S2 in one period of the phase A sine wave according to the signs of As and Bs (S40); Comprising an algorithm comprising a step (S50) of generating a square wave by comparing the sign of the sine wave on the A phase, and generating S3, the absolute position of the rotor by the number of the rising edge of the square wave to n It is achieved by the precise position detection method of the rotor using the output signal of the sine wave encoder.

The precision position detection method of the rotor using the output signal of the sine wave encoder according to the present invention has the effect of securing a new position calculation algorithm that can be easily implemented with a short calculation time.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

A general optical encoder is the same as that of FIG. 1, and the signals output through the square encoders are A and B phase waves as shown in FIGS. 2A and 2B. However, in the case of the sine wave encoder, as shown in FIG. 3, the sine wave type A phase and the cosine wave type B phase are output and the number of slits formed in the sine wave encoder's rotor is determined. The number of sine waves in one revolution is determined.

In addition, since the output signal of the sine wave encoder is an analog value, it can theoretically have an infinite multiplier according to the configuration of the interpolator, which is suitable for precision position detection.

Accordingly, the present invention provides a precise position detection method of a rotor using two phases (sine wave; A phase, cosine wave; B phase) output from a sine wave encoder. To this end, the present invention is to determine the number of slits formed in the rotor of the sine wave encoder (S10), and the number of sine waves generated in one revolution according to the number of slits of the rotor is defined as r, Defining an angle 360 / r corresponding to one period of the sine wave 10 as p (S20), and defining a signal of phase A as B and a signal of phase B as Bs, thereby generating a linear signal S1. (S30), generating a linear signal S2 in one period of the phase A sine wave according to the signs of As and Bs (S40), and comparing the sign of the sine wave of the A phase to the square wave. And generating an S3 which is an absolute position of the rotor by setting the number of rising edges of the square wave to n.

Here, in the case of the square wave encoder, the resolution corresponding to the angle corresponding to p is inevitably provided, but the sine wave encoder makes a linear signal which can derive the position information by manipulating the signals of phases A and B shown in FIG. If possible, the resolution can be increased infinitely, and the present invention can provide it.

That is, when As is an A-phase signal and Bs is a B-phase signal, a linear S1 signal of the form as shown in FIG. 4 is generated by subtracting the absolute value of Bs from the absolute value of As, as shown in Equation 1 below.

S1 = ｜ As ｜-｜ Bs ｜

Where As: A-phase signal, sine wave

Bs: B-phase signal, cosine wave.

Further, when S1 is manipulated according to the signs of As and Bs as shown in Equation 2 below, a linear signal S2 is generated within one period of the A-phase sine wave as shown in FIG.

For As ≥0 and Bs ≥ 0, S2 = (S1 / (8 * M) + 0.125) * p
For As ≥0 and Bs <0, S2 = (S1 / (8 * M) + 0.125) * p
If As <0 and Bs <0, then S2 = (S1 / (8 * M) + 0.125) * p
If As <0 and Bs ≥ 0, then S2 = (-S1 / (8 * M) + 0.875) * p

delete

delete

delete

delete

delete

delete

delete

Where As: A-phase signal, sine wave

Bs: B-phase signal, cosine wave

M: the maximum size of As and Bs.

In addition, by comparing the sign of the sine wave on the A phase, a square wave as shown in Fig. 6 can be generated, and n is the number of rising edges of the square wave of Fig. 6 generated from the sinusoidal encoder while the rotor rotates from the initial position. At this time, the absolute position S3 of the rotor can be calculated as Equation 3 below.

S3 = p * n + S2

Such an algorithm can be applied to the memory and the processor of the interpolator, whereby a precise position detection method of the rotor using the output signal of the sine wave encoder is achieved. And the symbol "*" used in the description and claims of the present invention means multiplication.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications, and variations will readily occur to those skilled in the art without departing from the spirit and scope of the invention. Therefore, it should be understood that the disclosed embodiments are to be considered in an illustrative rather than a restrictive sense, and that the true scope of the invention is indicated by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof, .

1 (a) and (b) is a view showing a schematic structure of a conventional optical encoder,

FIG. 2 is a diagram illustrating square waves of phase A and phase B output from the optical encoder of FIG. 1.

3 is a view showing the sine wave and cosine wave of the A phase and B phase output from the sine wave encoder according to the present invention,

4 is a diagram illustrating generation of S1 which is a linear signal made through FIG. 3,

FIG. 5 is a diagram illustrating generation of S2 which is a linear signal made through FIG. 4;

6 is a diagram illustrating a square wave generated by comparing the signs of a sine wave on A phase.

Description of the Related Art

10: 1 cycle of sine wave

Claims (5)

In the precision position detection method of the rotor using two phases (sine wave; A phase, cosine wave; B phase) output from a sine wave encoder, Determining the number of slits formed on the rotor of the sinusoidal encoder (S10); Defining the number of sine waves generated in one revolution according to the number of slits of the rotor as r, and defining an angle 360 / r corresponding to one period of the sine wave as p (S20); Defining the signal of phase A as B and the signal of phase B as Bs and thereby generating a linear signal S1 (S30); Generating a linear signal S2 in one period of the phase A sine wave according to the signs of As and Bs (S40); Generating a square wave by comparing the sign of the sine wave on the A phase, and generating S3 which is an absolute position of the rotor by setting the number of rising edges of the square wave to n (S50); Precision position detection method of the rotor using the output signal of the sine wave encoder, characterized in that comprises an algorithm consisting of. The method of claim 1, Generation of S1 of the step (S30) is the precision position detection method of the rotor using the output signal of the sine wave encoder, characterized in that as follows. <Equation 1> S1 = ｜ As ｜-｜ Bs ｜ Where As: A-phase signal, sine wave Bs: B-phase signal, cosine wave. The method of claim 1, Generation of S2 of the step (S40) is a precision position detection method of the rotor using the output signal of the sine wave encoder, characterized in that the following equation (2). <Equation 2> For As ≥0 and Bs ≥ 0, S2 = (S1 / (8 * M) + 0.125) * p For As ≥0 and Bs <0, S2 = (S1 / (8 * M) + 0.125) * p If As <0 and Bs <0, then S2 = (S1 / (8 * M) + 0.125) * p If As <0 and Bs ≥ 0, then S2 = (-S1 / (8 * M) + 0.875) * p As: A phase signal, sine wave         Bs: B-phase signal, cosine wave  M: the maximum size of As and Bs. The method of claim 1, Generation of S3 of the step (S50) is the precision position detection method of the rotor using the output signal of the sine wave encoder, characterized in that the following equation (3). <Equation 3> S3 = p * n + S2 The method according to any one of claims 1 to 4, The algorithm is a precision position detection method of the rotor using the output signal of the sine wave encoder, characterized in that applied to the memory and processor of the interpolator for converting the analog output of the encoder into a digital output.

Images