KR100384173B1 - Apparatus and method for high resolution processing of encoder signal for a motor control - Google Patents

Abstract

The present invention provides a high resolution encoder signal processing apparatus for a motor control and a method thereof, wherein the method is an analog signal input from an encoder for detecting the position and speed of a motor by applying the M method in the high resolution encoder signal processing apparatus for motor control. To detect the digital position value by counting the changed digital pulse by using the counter in the flex to generate 4 multiply pulses synchronized to the rising and falling edges of the digital signal to improve the resolution of the digital signal. Steps; When the digital position value is detected, applying the T measurement method to detect the micro position, simultaneously sampling and holding the analog Sin / Cos signal of the encoder with an A / D converter to read the micro position and applying the arc tangent function to obtain the micro position. ; Calculating the current position of the motor by adding up the detected digital position value and the micro position value by analog signal detection when the micro position is detected; Comprising the step of calculating the instantaneous speed by using the speed sampling time at the calculated current position, it detects the position and speed of the motor with high resolution to improve the speed response characteristics, low speed driving capability and speed control range.

Description

High Resolution Encoder Signal Processing Apparatus and Method for Motor Control {APPARATUS AND METHOD FOR HIGH RESOLUTION PROCESSING OF ENCODER SIGNAL FOR A MOTOR CONTROL}

The present invention relates to a high-resolution encoder signal processing apparatus and method for controlling the motor, and more particularly, the speed of the encoder signal that can be generated per rotation of the motor when the motor is applied to the analog signal (Sin / Cos) output type incremental encoder And a high resolution encoder signal processing apparatus and method for improving position resolution.

Recently, with the rapid development of the automatic control system, the use of various sensors and their application technologies have been remarkably developed for precise control of the control target. Especially, in systems such as machine tools that require high performance control, torque, speed, position Precise control is required, so the dependence of the sensor is a big part of the overall system performance.

As shown in FIG. 1, the speed control of the three-phase AC motor uses the DSP 120 for high-performance motor control through real-time calculation. And a current controller 122 for controlling the speed of the motor 300, and a current controller 122 for controlling the current value for the speed control of the motor 300. The current control output from the current controller 122 is also included. PWM (Pulse Width Modulation) inverter unit 130 for converting DC voltage to AC voltage so that the motor 300 can be driven at the required speed by generating a variable voltage and frequency according to the value, for PWM algorithm and current control The motor phase current detection unit 200 and the encoder signal processor 140 for controlling a constant reference speed by receiving the actual speed of the motor 300. The basic principle for the speed control of the three-phase AC motor through the above configuration Is following same.

In general, incremental encoders and absolute encoders are mainly used as speed detection apparatuses to implement high-performance vector control systems in the industry, and in general, inexpensive incremental encoders are used. .

In the speed detection method using an incremental encoder, the most common method is pulse counting, periodic measuring, and a mixture of two types. However, it is difficult to detect minute position information.

The pulse counting method (M method) is the most widely used method, and is a method of calculating a speed by measuring the number of encoder pulses input for a predetermined time (speed control period) as shown in FIG. 2A. Where Ncount is the number of M counts, and Ts is the sampling time (velocity sensing time) .This method has a constant sampling time and simple hardware, but has low accuracy because of the small number of encoder pulses input at low speed operation. Error due to rate sampling time ( Therefore, the speed ripple of the motor is caused. Therefore, in order to improve the precision, it is necessary to use a product with many encoder pulses output per revolution of the motor or to increase the sampling time sufficiently.

In addition, as shown in FIG. 2B, a method of measuring a period (T method) is a method of measuring an interval of encoder pulses and calculating a speed using the inverse thereof, and a high frequency reference clock pulse is required to measure the period. In 2b, T _SL is the sampling time at low speed operation, T _SH is the sampling time at high speed operation, N1 is the count number at low speed operation, N2 is the count number at high speed operation. Because of the tight pulse intervals, the measurement time is short, and at low speeds, the encoder pulses are longer, resulting in longer measurement times. This can increase the burden on the hardware and increase the speed error if the encoder pulse contains noise. It has the disadvantage that it results in a sampling time variation of the system.

In addition, the variable sampling method (M / T method) is the most widely used method, and can be said to be a method that mixes the advantages of the pulse count method (M method) and the period measuring method (T method). As shown in the figure, a period of time from the closest encoder pulse after the basic sampling time to obtain the position information (θ) and the remaining minute position information (dθ) by using the pulse counting method is set during this time. In Fig. 2C, Ts is a constant sampling time (for pulse counting), dt is a variable time for speed calculation (for periodic measurement), N1 is a counter count by pulse counting, and N2 is a periodic measuring method. The number of counters by

The speed error that can occur when using this method to be.

Here, the reference clock MCLK is a high frequency clock pulse for measuring the time of the counted encoder pulses. For example, when the reference clock is 40 ns and the velocity sampling time is 1 ms, the speed generated during 1,000 rpm operation is obtained. Speed error due to sampling △ = 40ns * 1000rpm / (40ns + 1ms) => Approximate value is 0.04rpm. Therefore, in order to reduce speed error, it is necessary to reduce the time of reference clock by hardware or increase sampling time of speed controller. However, if you increase the sampling time of the speed controller by this method, when you measure the first rapidly changing speed, the instantaneous speed cannot be input due to the delay due to the measurement time, causing the instantaneous speed error, and the second sampling time. Is proportional to the number of encoder pulses, so increasing the sampling time counts more encoder pulses, resulting in more bits The design of the counter is required, which is a hardware burden.

To sum up the above problem, firstly, there is a problem that there is a limitation of the speed measurement.

In other words, the most widely used variable sampling method detects the average speed during the sampling period, resulting in a delay due to measurement, especially at low speeds, as the period of the pulse increases, the delay of the measurement time becomes larger, and at low speeds. The sampling period is limited by the resolution of the encoder. The lower limit of the controllable speed refers to the minimum value of the speed at which at least one encoder pulse can be obtained per sampling period, and the relation is expressed by Equation 1 below.

Here, ppr: pulse per revolution, TS: velocity sampling time.

For example, in the case of an encoder of 1024 ppr, assuming that the speed sampling period is 1 ms, the motor speed should be 58.59 rpm or more according to the above equation in order to obtain one encoder pulse. In order to achieve this, the sampling period must be 19.5㎳ or more and the maximum frequency bandwidth is limited to 51.28㎐. Therefore, in order to measure the speed without time delay in the extremely low speed region, it is possible to increase the number of encoder pulses in hardware. do.

Second, there is a problem that the limitation of speed precision is followed.

In other words, in order to increase the resolution of motor speed detection, an encoder with a high output pulse number per rotation of the encoder may be used, or a multiplication factor may be used. The use of a high number of encoders increases the system cost and the electric rotation speed. The method of using multiplication of 4 multiply the phase error (duty error) and duty error (deterioration: 1/8 to 1/10 of 1 pulse period) of the encoder itself. This causes a phenomenon of amplifying the errors of the encoder pulse when quadrupling, making precise speed and position control difficult.

Since the machining precision specification of a machine tool for precision machining is generally about 0.5 to 0.1 占 퐉, it is difficult to satisfy the required specifications when the encoder signal processing is performed in a general manner without using a high resolution signal processing method.

The present invention has been made to solve the conventional problems as described above, and an object of the present invention is to provide an encoder signal that can be generated per motor revolution during motor control using an analog signal (Sin / Cos) output type incremental encoder. The present invention provides a high resolution encoder signal processing device for motor control with improved speed and position resolution, and a high resolution encoder signal processing method for motor control applied to the signal processing device.

1 is a block diagram of a general motor controller.

Fig. 2A is an illustration of motor position measurement of pulse counting applied to the apparatus of Fig. 1;

FIG. 2B is an illustration of motor position measurement of a periodic measurement applied to the apparatus of FIG. 1; FIG.

2C is an exemplary diagram of motor position measurement of a variable sampling method applied to the apparatus of FIG.

3 is a block diagram of a high resolution encoder signal processing apparatus for controlling a motor according to an embodiment of the present invention;

4 is a detailed block diagram of Flex in FIG.

5 is an exemplary diagram of an encoder output signal in FIG. 3;

6 is a circuit diagram of an encoder signal receiver in FIG. 3;

7 is a signal waveform diagram at the time of position detection using the analog signal output type encoder according to the present invention;

8 is a relationship diagram between time and position during instantaneous speed detection according to the present invention;

Fig. 9 is an illustration of the case where one sine wave rotation according to the present invention is divided into n power bits of two.

10 is a signal waveform diagram of a 2 n-2 power bit division method using 4 multiplication according to the present invention.

11 is an exemplary linearization diagram of a sine wave according to the present invention.

12 is a signal waveform diagram of a method of detecting a position by dividing one period into eight sections according to the present invention;

13 is a signal waveform diagram at the time of calculating the arc tangent for each of eight sections according to the present invention;

14 is a signal waveform diagram at the time of minute position detection in accordance with the present invention.

15 is a flowchart of a method for processing a high resolution encoder signal for controlling a motor according to an embodiment of the present invention.

16 is an exemplary view of calculating final position information according to the present invention.

Figure 17 is a relationship diagram between time and position at the time of minimum position detection in accordance with the present invention.

Explanation of symbols on the main parts of the drawings

11A, 11B: Encoder signal receiver 12A, 12B: Zero voltage detector

13: A / D Converter 14: Flex

15: buffer 16: DSP

According to an aspect of the present invention, there is provided an analog output type incremental encoder, comprising: a low pass filter and a differential amplifier, and an encoder signal receiving unit configured to output phase current and motor position information fed back by driving of a motor; A zero voltage detector detecting a time point at which the Sin / Cos analog signal output from the encoder signal receiver passes 0V; A flex for extracting digital position information from the signal output from the zero voltage detector; An A / D converter capable of simultaneously sampling a plurality of channels or more, and converting an analog signal output from the encoder signal receiving unit into a digital signal and providing the signal as necessary for calculating a micro position; The digital signal processing outputted from the A / D converter and the flex includes a DSP for controlling the position and speed of the motor. The present invention further includes (a) detecting the position and speed of the motor by applying pulse counting. Converting an analog signal input from an encoder into a digital signal for detecting the digital signal, and counting a pulse of four multiplications synchronized with rising and falling edges of the digital signal to improve the resolution of the digital signal; (b) when the digital position value is detected, sampling and holding an analog Sin / Cos signal converted into digital information by an A / D converter by applying a periodic measurement method, reading and applying an arc tangent function to obtain a micro position; ; (c) calculating the current position of the motor by adding up the detected digital position value and the micro position value by analog signal detection when the micro position is detected; (d) calculating the instantaneous velocity using the velocity sampling time at the calculated current position.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram of a high resolution encoder signal processing apparatus for controlling a motor according to an embodiment of the present invention, FIG. 4 is a detailed block diagram of a memory unit in FIG. 3, and FIG. 5 is an exemplary diagram of an encoder output signal in FIG. 3. 6 is a circuit diagram of an encoder signal receiving unit in FIG. 3, FIG. 7 is a signal waveform diagram when detecting a position using an analog signal output encoder according to the present invention, and FIG. 8 is a relationship between time and position when detecting instantaneous speed according to the present invention. 9 is an exemplary diagram in the case where one rotation of a sine wave according to the present invention is divided into n power bits of two.

In addition, Figure 10 is a signal waveform diagram of the n-2 power bit division method of 2 using a multiplier according to the present invention, Figure 11 is an illustration of the linearization of the sine wave according to the present invention, Figure 12 is a view according to the present invention FIG. 13 is a signal waveform diagram of a method of detecting a position by dividing a period into eight sections. FIG. 13 is a signal waveform diagram of calculating arc tangent for eight sections according to the present invention. Figure 15 is a signal waveform diagram of the time, Figure 15 is a flow chart of a high-resolution encoder signal processing method for controlling the motor according to an embodiment of the present invention, Figure 16 is an exemplary view of calculating the final position information according to the present invention, Figure 17 is according to the present invention The relationship diagram between time and position at the minimum position detection.

In FIG. 3, A + (B +) is a Sin (Cos) signal output from the encoder, A- (B-) is an inverted signal of A + (B +), and R phase is a signal indicating a reference position. The output can be applied to detect the motor rotor position, but will not be described in detail below.

5 shows a signal input from an encoder during encoder processing.

3 and 5, since the Sin / Cos wave signals input to the encoder 400 can be used 10m or more away from the normal motor, a line drive method (two strands-A +, A-) is used. When the phase currents A +, A-, B +, and B- detected and returned from the sensor according to the driving of the motor and the actual speed of the motor are applied to the encoder signal receiving units 11A and 11B, the encoder signal The low-pass filter and differential amplifier (not shown) provided in the receivers 11A and 11B extract each signal returned by pure analog components through differential amplification and low-pass filtering, and then zero voltage to generate a pulse for use in digital position detection. It passes through the Zero Crossing Detectors 12A and 12B and is converted into digital pulses ADIG_SENC and BDIG_SENC and input to the flex 14.

Since the encoder signal receivers 11A and 11B apply a method of loading a signal at a constant DC voltage to protect the signal information returned from the motor from noise, the DC signal is removed by a differential amplifier or the like when the signal is restored. Sin / Cos wave signals of pure analog components are extracted through a filter. The zero voltage detection units 12A and 12B are analog signals of Sin / Cos waves to obtain digital position information in a high resolution encoder signal processing scheme. Detects the time point passing through 0V and outputs information (ADIG_SENC, BDIG_SENC). In the above, ADIG_SENC means 0V detection of feedback A-phase current, and BDIG_SENC means 0V detection of feedback B-phase current. The analog signals ADC_ENCA and ADC_ENCB output from the encoder signal receiver 11A are inputted to the A / D converter 13 to detect the minute position. The period is divided into eight sections, and the micro position interpolation software algorithm calculates the micro position using an arctangent function. The A / D converter 13 is an A / D converter capable of simultaneously sampling two channels or more. In the above, in the case of ADC_ENCA and ADC_ENCB, which are analog signals inputted to the A / D converter 13, the meaning of ADC means information of a destination, which is a signal input to the A / D converter, and ENCA and ENCB. Means phase A and phase B of the encoder. That is, the phase current input to the A / D converter 13. The flex 14 is a type of programmable logic device. Logic designed as a RAM-structured device commonly used in controllers and communication systems is compiled and downloaded to the device. As shown in Fig. 4, the flex 14 is used to obtain signals (ADIG_SENC, BDIG_SENC), i.e., digital information, for the time when the feedback Sin / Cos analog A and B phase current passes 0V. A synchronization unit 14A for synchronizing the signal to the master clock CLK, and a multiplier 14B and 24 bits for improving the resolution of the digital pulses A_DIG and BDIG synchronized to the master clock CLK. And a 16D bit buffer 14D. The CONVST input to the synchronization unit 14A is a control signal output from a DSP and samples position information. It is a control signal to hold the converted position information amount during one control period and to read the current value from the digital position detector and the A / D converter in DPS, and '#' is added at the end of this signal. If the corresponding signal In addition, the A_HOLD and B_HOLD signals output from the synchronization unit 14A are signals applied to a correction algorithm and are A_DIG and B_DIG signals when the CONVST # signal is enabled from the DSP. The 4-multiplier 14B is used to improve the resolution of the digital signal. When one cycle of the digital signal is considered, one period is used for only high and low information. In order to detect a precise position value from this information, one period is further subdivided to extract 90 ° intervals of information from the A_DIG and B_GIG signals, i.e., the rising and falling edges of the A_DIG and B_DIG signals. It detects the existing high or low signal to generate four pulses having a clock width. In addition, the CNT_LATCH signal applied to the digital position detector 14C by the synchronization unit 14A. Is the same as the CONVST # signal described above, and is a positive enable signal, which is a control signal for holding a current value to read the position information value from the DSP. The digital position detector 14C includes a counter circuit. The number of digital signals (ENC_4fold) output from the 4-multiplier (14B) is counted, and a function of increasing or decreasing the U / -D signal from the current counter number is performed. The U / -D signals include A_DIG, The B_DIG signal detects whether the current rotation of the motor rotates in the forward direction or in the reverse direction. Further, according to FIG. 6, the encoder signal receivers 11A and 11B include a low pass filter LPF and a differential amplifier. AMP). In the circuit shown in Fig. 6, R1 and R2 are adjusted so that the output voltage range is appropriate according to the reference voltage of the A / D converter 13 to be used.

Next, a method of obtaining 32-bit information for motor position (speed) detection will be described.

As shown in Fig. 7, the pulse information method (M method) is applied to obtain digital information through zero voltage detection of an analog signal input from the encoder signal receivers 11A and 11B for position and speed detection. In order to improve the resolution of the information signal, a pulse (4 multiplication) synchronized to the rising and falling edges of the ADIG_SENC and BDIG_SENC signals is generated, and the digital position value (θdigital) is detected as a coefficient of the digital pulse through a 24-bit counter.

In order to apply the T method to detect the micro position, the A / D converter 13 is applied to simultaneously sample, hold, and read the analog sin / cos signal output from the encoder signal receiver to read the arc tangent function. Apply to find the micro position (θanalog). Configures the lower 8 bits from the total 32 bits of location information. To detect the micro position.

Subsequently, the current position (32-bit information) is obtained, and the current position can be expressed by the sum of the digital position value θdigital and the small position value θanalog by analog signal detection. That is, θ = θ digital + θ analog.

In addition, as shown in FIG. 8, the instantaneous speed Δw is obtained using the speed sampling time Ts as shown in Equation 2 below.

The location information detection will be described in more detail.

Digital position (θdigital) detection uses an quadruple (14B) to quadruple the encoder signal to 4x (2048 x 4 = 8192ppr when using 2048 pulse encoders) to improve digital position accuracy and the 24-bit position built into the flex 14 The multiplier pulses are counted by the detector 14 to obtain a digital position value [theta] digital.

In the analog wave detection, the square wave pulse encoder can no longer obtain accurate position information between the edges of the encoder pulse, but in the analog signal output type encoder, the position value can be obtained by subdividing the angle by the analog value within one period. Can be.

The conditions required for obtaining the micro position information (dθ) using the analog signal output type encoder are shown below.

1) Input waveform consists of two waveforms, Sine / Cosine.

2) Time delay required for signal processing and input waveform detection using DSP is acceptable.

3) In addition to the A / D converter 13, a separate zero voltage detection unit 12A, 12B circuit is designed to obtain digital position information, and the digital information is counted using a 24-bit counter.

4) The input channel of the A / D converter 13 can be simultaneously sampled.

5) The encoder outputs 2048 sine waveforms per motor revolution.

Therefore, when the n-bit A / D converter 13 is used to detect the micro position assuming that the encoder signal is the ideal Sin / Cos signal, the micro position detection method is a method of dividing 1 rotation of sin wave into 2 ⁿ bits, It can be divided into 2 ^n-2 bit division method using 3 ⁿ and 2 ^n-3 bit division analysis method using 8 divisions.

The method of dividing 1 sinsin wave into 2 ⁿ bits is divided into 2 ⁿ bits (n = number of A / D converter bits) by dividing one cycle of the analog signal output encoder as shown in FIG. The minimum smile position size is Same as If, when using the (dividing one period into ²¹² of the encoder) 2048 output pulse encoder with the 12-bit A / D converter can be obtained per revolution of the motor up to 8,388,608 (= 2048 * ²¹²⁾ resolution.

2) The 2 ^n-2 bit division method using multiplication of 4 is a concept corresponding to dividing one period of the encoder by 2 ⁿ bit resolution as shown in FIG. 10, and the multiplication signal of ADIG_SENC and BDIG_SENC (2 ^2). By using), 0 ~ 2pi is divided into 4 parts, and the resolution between each multiplication signal is divided by 2 ^n-2 .

That is, 2 ⁿ (one cycle resolution) = 2 ² (four times multiplication signal) * 2 ^n-2 (micro position resolution from 0 to pi / 2).

In addition, the 2n-3 bit segmentation analysis method using 8 divisional divisions is not considered in the method of detecting one cycle with 2 ⁿ bit resolution without 4 multiplication or detecting signals from 0 to pi / 2 through 4 multiplication. As a matter of fact, the Sin / Cos signal does not have linearity above pi / 4. Accordingly, as shown in FIG. 11, a method of improving A / D precision by improving A / D conversion of only 0 to pi / 4 interval values having linearity by dividing 0 to 2 pi into eight sections is required.

Since one encoder has a position resolution of 2 ⁿ , when divided into 8 sections, resolution between 0 and pi / 4 is 2 ^nS (where S is a bit value 3 for 8 sections (2S = 8 sections)). to be.

That is, 2 ⁿ (one cycle resolution) = 2 ^S (8 sections) * 2 ^nS (micro position resolution from 0 to pi / 4).

For example, the position resolution when the number of encoder pulses is 2048 [ppr] and the A / D converter 13 is 12 bits is 8,388,608 (= 2048 * 2 ³ * 2 ^12-3 ).

The above-described methods for detecting the small position are concepts arranged under the assumption that the encoder signal is ideal. However, in general circuits, the influence of noise is not negligible, especially noise in a drive system driving a motor is an important item to consider in signal processing. In general, the lower two bits of the signal detected by the A / D converter 13 are bits that are likely to be contaminated with noise, and thus, it may be difficult to secure reliability.

The high-resolution position detection method implemented in consideration of this point is the same as the one-cycle interpolation method of Sin / Cos wave using ④ arc tangent function.

④ In the case of one period interpolation of Sin / Cos wave using the arc tangent function (Atan function), FIG. 13 (a) shows the signal output from the encoder and the absolute value of the Sin / Cos signal inputted to discriminate eight classified sections. Obtain

The result of taking an absolute value for eight periods of one period of the Sin / Cos wave is shown in Fig. 13B. The micro position of each section is obtained by the arc tangent function, and it is necessary to find the magnitude of the position value to prevent the saturation of the arc tangent function.

FIG. 13 (c) shows the result of linearizing one section (0 to 2 pi) of Sin wave by adding the calculated values (Δθ) to each of eight sections, and in the case of the 12-bit A / D converter 13, 1024 (= It is divided into 2 ¹⁰ (=> 8 intervals (2 ³ ) * resolution of each interval (2 ⁷ )).

The implementation of this high resolution position interpolation algorithm is made as shown in Figs. 14 is an algorithm implemented in actual software, and FIG. 15 is a flowchart of the implemented program.

According to Fig. 14, a method of dividing a period into eight sections of the micro position detection method is applied, and sign_A and sign_B are software flags for discriminating whether A phase and B phase are positive values or negative values.

Fig. 15 calculates the position values of the A and B signals detected from the two channels of the 12-bit A / D converter 13 by using the arc tangent function, and the calculated values are currently displayed in any mode (8 sections). It is a flow chart for determining whether there exists according to the algorithm defined in FIG.

More specifically, a standard arc tangent table is prepared, and the A / D converter 13 samples / holds the encoder input signal and detects the motor position θdigital by the M number method (ST221 to ST23).

Subsequently, a micrometer (θanalog) is detected by a period measuring method, and | a |, which is the absolute value of the sine of the encoder signal respectively input to the channels A and B, is | b | Set Cal.a1 depending on whether it is larger (ST24 to ST27).

Then, | A | and | B | are compared with each other, the position value Cal.θ is calculated according to the sign of Sign_A and Sign_B (ST28 to ST42).

The instantaneous speed of the motor can be obtained from the calculated position value Calc.θ (ST43).

That is, θ = θdigital + θanalog

In order to improve the digital position resolution, the actual signal processing method has improved the resolution of the digital pulse by using the quadratic signal, and the method of using the arc tangent function by dividing the linear section of the sin wave into 8 sections to find the micro position. I use it at the same time.

Fig. 16 is the sum of the position information values finally calculated is the sum of the digital position values and the micro position (the maximum information of one period of Sin / Cos wave composed of 10 bits) interpolated by the A / D converter and the arc tangent function. Of these, the upper two bits are equivalent to the effect of multiplication.

According to the high resolution encoder signal processing apparatus and method for controlling the motor of the present invention, the following effects are obtained.

In general, the performance of the speed control loop is limited by the sensor's bandwidth and noise. However, the high speed position processing allows the sensor's bandwidth to be expanded and the quantization noise to be reduced, so the performance of the speed control loop is not limited by the sensor. Can be ignored. In other words, speed measurement is ideal.

Thus, according to the present invention, there is an effect of improving the speed response characteristics. Speed detection with sufficient accuracy is possible even in short sampling periods, and the speed control cycle can be set to 1 to 2 times the current, thereby reducing the delay of the control loop to improve responsiveness. This can shorten the response time due to the load torque variation and reduce the speed drop. That is, the influence of the sensor delay can be reduced and the bandwidth of the sensor can be improved.

And it has the effect of improving the low speed driving capability and the speed control range. By reducing the quantization error of the speed measurement, the minimum measurable speed is smaller, which improves the low speed control characteristics and increases the speed control range. The noise reduction of the sensor can lead to an extension of the control range.

The speed detection using the high resolution encoder processing technique and the minimum speed control range in the case of using the commonly used square wave pulse type encoder will be compared with reference to FIG.

In FIG. 17, assume that the sampling time of the speed controller is 250 ms for the minimum speed detection.

The formula for finding the minimum velocity is Is,

1) (Analog Output Encoder) For 2 million resolutions with high resolution processing:

2) (Square wave pulse output type encoder) In case of 5,000ppr using general M / T method:

The use of an interpolation method for detecting a micro position as in the above calculation has the advantage that the motor can be controlled from an extremely low speed.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Therefore, the above description does not limit the scope of the following claims.

Claims (8)

In the analog output incremental encoder, An encoder signal receiver including a low pass filter and a differential amplifier, the phase current and motor position information being fed back according to the driving of the motor; A zero voltage detector detecting a time point at which the Sin / Cos analog signal output from the encoder signal receiver passes 0V; A flex for extracting digital position information from the signal output from the zero voltage detector; An A / D converter capable of simultaneously sampling a plurality of channels or more, and converting an analog signal output from the encoder signal receiving unit into a digital signal and providing the signal as necessary for calculating a micro position; And a DSP for calculating the position and speed of the motor by calculating the digital signal processing output from the A / D converter and the flex. The method of claim 1, wherein the encoder signal receiving unit, A low pass filter for passing only signals in the low frequency band; A differential amplifier for differentially amplifying a low frequency signal passing through the low pass filter; And a plurality of resistors in which an output voltage range is set according to a reference voltage of the A / D converter. The method of claim 1, wherein the flex is A synchronization unit for synchronizing the digital position detection time and the analog signal detection time of the motor with respect to the control clock of the controller; A multiplier for improving the resolution of the digital position information of the motor; And a digital position detector for detecting a digital position of the motor with an improved resolution by the quadruple multiplier. (a) By applying the pulse counting method, the analog signal input from the encoder is converted into a digital signal for detecting the position and speed of the motor, and synchronized to the rising and falling edges of the digital signal to improve the resolution of the digital signal. Counting pulses of multiplication to detect a digital position value; (b) when the digital position value is detected, sampling and holding an analog Sin / Cos signal converted into digital information by an A / D converter by applying a periodic measurement method, reading and applying an arc tangent function to obtain a micro position; ; (c) calculating the current position of the motor by adding up the detected digital position value and the micro position value by analog signal detection when the micro position is detected; (d) calculating the instantaneous speed by using the velocity sampling time at the calculated current position. The method of claim 4, wherein In the step (a), the digital position detection is performed by multiplying the encoder signal using a multiplier by a set multiple in order to improve digital position accuracy, and counting the multiplier pulse with a digital position detector built in the flex to calculate the digital position value. High resolution encoder signal processing method for a motor control, characterized in that the. The method of claim 4, wherein In the step (b), the minute position detection may be performed by dividing one rotation of a sin wave into 2 ⁿ bits when an n-bit A / D converter is used to detect the minute position when the encoder signal is a Sin / Cos signal. A high resolution encoder signal processing method for a motor control, comprising a 2 ^n-2 bit division method using multiplication and a 2 ^{n- 3} bit division analysis method using eight interval divisions. The method of claim 6, wherein the step micro-position detection is performed by applying a period interpolation method of a sin / cos wave using an arc tangent function, and inputting sin / cos to discriminate intervals of signals output from the encoder by a predetermined number. The absolute value of the signal is calculated, the minute position of each section is calculated using the arc tangent function, and the calculated minute position of each section is summed to detect the minute position of one section of the Sin / Cos wave. High resolution encoder signal processing method for a motor control comprising a. delete