KR20000008601A - Motor speed detector - Google Patents

Abstract

PURPOSE: A motor speed detector is provided to successively detect a motor speed without a delay time. CONSTITUTION: A motor speed detector for obtaining a motor speed by an encode pulse generated from encoder. An encoder counter(120) counts the encoder pulse and a timer counter(130) counts timer clocks for counting an interval between the encoder pulses. A sampling counter(140) generates an interrupt signal according to a predetermined sampling period. An encoder counter memory(150) stores an encoder pulse count value counted by the encoder counter, and outputs a stored encoder pulse count value if the interrupt signal is received from the sampling counter. A timer counter memory(160) stores a timer clock count value counted by the timer counter(130), and outputs a stored timer clock count value if the interrupt signal is received from the sampling counter. If the interrupt signal is received from the sampling counter(140), a controller(170) operates each count value which is generated from the encoder counter memory and the timer counter memory for a present sampling period, operates a timer clock count value for a previous sampling period, and obtains a motor speed. Thereby, a motor speed detector successively detects a motor speed without a delay time, and a motor speed is precisely controlled.

Description

Motor speed detection device

The present invention relates to a speed detecting apparatus for a motor, and more particularly, to a speed detecting apparatus for a motor capable of continuously detecting the speed of the motor without a delay time.

In general, as shown in FIG. 1, a conventional motor speed detecting apparatus includes an encoder 10 that outputs an encoder pulse corresponding to a rotational speed of a motor, and the number of encoder pulses output from the encoder 10. Count the number of Encoder Counters (hereinafter referred to as "M counters") and timer clocks for counting the intervals between the encoder pulses. A timer counter 30, hereinafter referred to as "T counter", a sampling counter 40 for generating an interrupt signal at each predetermined sampling period, and the M counter 20 Calculates the speed of the motor by calculating the value counted through the T counter 30 and outputs a drive control signal for controlling the driving of the motor according to the obtained motor speed to the motor driving unit, not shown. Article It consists of a part 50.

An operation process of the conventional motor speed detection device configured as described above will be described with reference to FIG.

First, when the motor is driven, encoder pulses corresponding to the rotational speed of the motor shaft are output from the encoder 10, and the number of encoder pulses output from the encoder 10 is counted by the M counter 20, and the encoder is counted. The pulse count value m1 is input from the M counter 20 to the controller 50.

At the same time, the number of T clocks generated from the T clock generating means not shown is counted by the T counter 30, and the count value m2 of this T clock is input from the T counter 30 to the controller 50. do.

In addition, the X clock serving as a reference for the sampling period Tc generated from the X clock generating means, not shown, is counted by the sampling counter 40, and the interrupt signal is received from the sampling counter 40 every predetermined sampling period Tc. Is generated and this interrupt signal is input to the controller 50.

Here, when the interrupt signal is input from the sampling counter 40, the controller 50 waits until the encoder pulse is input from the encoder 10 (ΔT), and when the encoder pulse is input, the motor according to Equations 1 to 4 below. Find the speed Nf.

Here, "?" Is obtained by the following equation (2) as the angular displacement.

Here, "P" is the number of magnetic poles of the motor.

Here, "fc" is the frequency of the T clock [Hz].

In addition, the controller 50 compares the speed Nf of the motor obtained through Equations 1 to 4 with the target speed, and applies a driving control signal for controlling the motor to the target speed to the motor driving unit, not shown. The motor driving unit controls the speed of the motor by adjusting the current or voltage applied to the motor by the drive control signal from the controller 50.

However, in the conventional motor speed detector as described above, the encoder pulse count value m1 from the time when the first encoder pulse is input during the sampling period until the new encoder pulse is input after the sampling period has passed (Td). And since the speed of the motor is calculated according to the T clock count value m2, the speed of the motor is continuously detected by the delay time ΔT until the encoder pulse is input after the sampling period Tc has passed. There is a problem that can not control the speed of the motor quickly and precisely.

For example, the slower the speed of the motor, the faster the delay time ΔT until the encoder pulse is input after the sampling period Tc passes and the longer the speed detection time of the motor is, the faster the speed of the motor is controlled. In case of requiring an immediate response as in the position servo system, if the speed of the motor is not immediately controlled as described above, there is a problem that the position control cannot be performed quickly and precisely.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, by calculating the speed of the motor by calculating the count value before the current sampling period starts and the count value during the current sampling cycle, delay time It is an object of the present invention to provide a speed detecting apparatus for a motor capable of continuously detecting the speed of the motor without using the same.

Motor speed detecting apparatus according to the present invention for achieving the above object, an encoder counter for counting the encoder pulse output from the encoder, a timer counter for counting the timer clock for counting the interval between the encoder pulse, and a predetermined A memory for an encoder counter that stores the sampling counter that generates an interrupt signal according to the sampling period and the encoder pulse count value counted by the encoder counter, and outputs the stored encoder pulse count value when an interrupt signal is input from the sampling counter. And a timer counter memory device for storing the timer clock count value counted by the timer counter and outputting the stored timer clock count value when the interrupt signal is input from the sampling counter. When the interrupt signal is input from the sampling counter. String sampling And a control unit for calculating the speed of the motor by calculating each count value output from the encoder counter memory device and the timer counter memory device during the period and the timer clock count value for the previous sampling period.

1 is a schematic block diagram of a speed detecting apparatus for a motor according to a conventional example;

2 is a view for explaining the input-output relationship of the main components shown in FIG.

Figure 3 is a schematic block diagram of a speed detection device of a motor according to an embodiment of the present invention,

4 is a view for explaining the input-output relationship of the main components shown in FIG.

<Explanation of symbols for the main parts of the drawings>

110: encoder 120: encoder counter

130: timer counter 140: sampling counter

150: encoder counter register 160: timer counter register

170: control unit

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

3 is a schematic block diagram of a speed detecting device for a motor according to a preferred embodiment of the present invention. The speed detecting device for a motor according to the present invention, as can be seen with reference to the same drawing, the encoder 110 and M Counter 120, T Counter 130, Sampling Counter 140, Encoder Counter Register (150, hereinafter referred to as “M Counter Register”) and Timer Counter Register (Encoder Counter Register; 160, below , "T counter register" and a control unit 170.

In FIG. 3, the encoder 110 outputs encoder pulses corresponding to the rotational speed of the motor shaft, and the M counter 120 counts the number of encoder pulses output from the encoder 110 and counts the encoder pulses. The pulse count value m1 is output.

In addition, the T counter 130 counts the number of T clocks generated by the T clock generator, not shown, to count the interval between the encoder pulses, and outputs the count value m2 of the counted T clocks. Each time the encoder pulse is input from 110, the count value m2 of the accumulated T clocks is reset and counted.

In addition, the sampling counter 140 generates an interrupt signal every predetermined sampling period and inputs the M counter register 150, the T counter register 160, and the controller 170.

The M counter register 150 stores the encoder pulse count value m1 output from the M counter 120 and controls the stored encoder pulse count value m1 when an interrupt signal is input from the sampling counter 140. Enter (170).

In addition, the T counter register 160 stores the count value m2 of the T clock output from the T counter 130, and when the interrupt signal is input from the sampling counter 140, the T counter register 160 stores the count value m2 of the stored T clock. Input to the controller 170.

When the interrupt signal is input from the sampling counter 140, the control unit 170 receives an encoder pulse count value m1, a T clock count value m2, and an M counter register 150 and a T counter register 160. The motor speed is calculated by calculating the T clock count value (T1m2) after the last encoder signal is input among the sampling cycles of the previous cycle, and comparing the obtained motor speed with the target speed to control the motor at the target speed. The driving control signal is applied to the motor driving section not shown.

FIG. 4 is a view for explaining the input / output relation of the main components shown in FIG. 3, and the T clock count value m2 and the T clock counted by the encoder pulse and the T counter 130 output from the encoder 110 are shown. It is shown.

An operation example of the present invention configured as described above will be described in detail with reference to FIGS. 3 and 4.

First, when the motor is driven by the motor driving unit (not shown), an encoder pulse corresponding to the speed of the motor rotation shaft is output from the encoder 110.

The number of encoder pulses output from the encoder 110 is counted by the M counter 120 and the count value m1 of the encoder pulse is stored in the M counter register 150.

At the same time, the number of T clocks generated from the T clock generating means not shown is counted by the T counter 130, and the count value m2 of this T clock is stored in the T counter register 160.

At this time, the count value (m2) of the T clock counted by the T counter 130 as shown in Figure 4, each time the encoder pulse is input from the encoder 110, the accumulated value is reset to count do.

In addition, the sampling counter 140 generates an interrupt signal every predetermined sampling period by the X clock input from the X clock generating means, which is not shown according to the start signal input from the control unit 170, so that the M counter register 150 is generated. And the T counter register 160 and the control unit 170.

Here, the X clock is a reference frequency of the sampling period.

The count value m1 of the encoder pulse stored during the current sampling period Tc is inputted from the M counter register 150 to the controller 50 by the interrupt signal from the sampling counter 140 and the M counter register 150. The count value stored in is reset and the count value m1 of the encoder pulse of the next sampling period is stored.

At the same time, the T clock count value Tcm2 stored during the current sampling period Tc by the interrupt signal from the sampling counter 140 is input from the T counter register 160 to the controller 170.

Here, the control unit 170 is the count value (m1) of the encoder pulse input from the M counter register 150 and the T counter register 160 during the current sampling period (Tc) by the interrupt signal from the sampling counter 140. ) And the T clock count value Tcm2 and the T clock count value input from the T counter register 160 during the previous sampling period are substituted into Equation 5 below to obtain the angular speed? Of the motor.

Here, "T1m2" is the T clock count value after the last encoder pulse is input (T1) of the previous sampling period, "Tcm2" is the T clock count value during the current sampling period (Tc), and "n" is one sampling. If no encoder pulse is input during the cycle, the number of repeated samplings until the encoder pulse is input, "T2m2" is the T clock count value after the last encoder pulse is input (T2), and m1 is the current sampling cycle. Encoder pulse count value during the period Tc.

Then, the controller 170 compares each speed ω of the motor obtained by Equation 5 with the target speed, and applies a driving control signal for controlling the motor to the target speed to the motor driving unit, not shown. The motor driving unit controls the speed of the motor by adjusting the current or voltage applied to the motor by the drive control signal from the controller 170.

That is, in the prior art, since the motor speed is obtained by calculating the count value of the encoder pulse and the T clock after the first encoder pulse is input from the sampling cycle until the last encoder pulse is input, the sampling cycle is obtained. There was a problem that the speed control is not performed quickly and precisely because the delay time is generated until the encoder pulse is input afterwards. By using the value stored in the previous sampling cycle, the speed of the motor can be calculated immediately and continuously in every sampling cycle without delay, allowing the speed of the motor to be controlled quickly and precisely.

As described above, according to the present invention, the count value is stored in the memory device at each sampling period, and the speed of the motor is calculated immediately and continuously by using the count value stored in the memory device and the count value of the previous sampling period. The speed is detected immediately and continuously without delay, so that the speed control of the motor can be performed quickly and precisely.

Claims (3)

In the speed detection device of the motor that obtains the speed of the motor by the encoder pulse output from the encoder, An encoder counter for counting the encoder pulses; A timer counter for counting a timer clock for counting the interval between the encoder pulses; A sampling counter for generating an interrupt signal according to a predetermined sampling period; An encoder counter memory device that stores the encoder pulse count value counted by the encoder counter and outputs the stored encoder pulse count value when an interrupt signal is input from the sampling counter; A timer counter memory device for storing the timer clock count value counted by the timer counter and outputting the stored timer clock count value when an interrupt signal is input from the sampling counter; When the interrupt signal is input from the sampling counter, each count value output from the encoder counter memory device and the timer counter memory device during the current sampling period and the timer clock count value for the previous sampling period are calculated to calculate the speed of the motor. Speed detection device for a motor, characterized in that consisting of a control unit for obtaining the. The method of claim 1, wherein the control unit, The timer clock count value after the last encoder pulse input in the previous sampling cycle is added to the value obtained by subtracting the timer clock count value after the last encoder pulse input in the current sampling cycle from the timer clock count value during the current sampling cycle. The motor speed detection device, characterized in that the speed of the motor is obtained by dividing the encoder pulse count value during the current sampling period. 3. The motor speed detection according to claim 2, wherein when there is no input of the encoder pulse during one sampling period, the number of times of sampling repeated until the input of the encoder pulse is multiplied by the timer clock count value during the current sampling period. Device.