KR0160674B1 - Communicating error protecting method of servo drive - Google Patents

Abstract

The commutation error prevention method of the servo motor drive according to the present invention comprises the steps of setting a predetermined current control address by reading the state of the u, v, w signal generated from the encoder; Setting a predetermined current control address by a microprocessor when the motor rotates after the setting and rises (polling) on u; And if the rising (polling) of u phase is normal or noise, the current control address is set to 1 or 1024 to control the motor, and if it is noise, the current control address of address 1 or 1024 is set. And controlling the motor with the current control address according to the position pulse counting by the microprocessor.

In this way, since the current control address is set by determining whether the rising (polling) of the u phase is normal or caused by noise, there is an advantage of preventing abnormal rotation or damage of the conventional motor.

Description

How to prevent the commutation error of the servo motor drive

1 is a schematic system configuration diagram of a control system of a conventional AC servo motor.

2 is a signal waveform diagram showing the mutual relationship between signals u, v, and w generated from an encoder when the motor rotates clockwise.

3 and 4 are schematic system flow diagrams of a servo motor drive control system according to a method for preventing commutation errors in a servo motor drive of the present invention.

* Explanation of symbols for main parts of the drawings

11 motor 12 encoder

13: microprocessor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC servo motor drive for controlling an AC servo motor with an encoder. In detail, an abnormal signal is generated due to external noise from an encoder attached to the servo motor. However, the present invention relates to a method of preventing a commutation error of a servo motor drive that can prevent abnormal rotation and damage of the motor by controlling the current of the motor normally.

In general, a motor requires a drive for driving the motor. An AC servo motor also needs a drive for driving the motor, and an encoder is provided in the drive for generating a predetermined signal for current control. In such an AC servo motor, in order to control the current of the motor, the motor drive receives a commutation signal from an encoder attached to the motor to control the current.

Figure 1 of the accompanying drawings schematically shows a control system of such a conventional AC servo motor.

Referring to this, the AC servo motor 11 is provided with an encoder 12 which transmits a predetermined commutation signal for controlling the current of the motor to the microprocessor 13 of the servo motor drive, and the encoder 12 and the microprocessor are installed. 13 is electrically connected. Here, the connection relationship will be described in more detail. The transmission lines of the position pulse signals A and B generated from the encoder 12 are connected to an up / down counter (not shown) of the microprocessor 13. It is. The transmission line of the commutation signals u, v, and w generated from the encoder 12 is connected to the interrupt port of the microprocessor 13, and the signal u and the remaining signals v, w The transmission line is connected to input ports of the microprocessor 13, that is, P0, P1, and P2, respectively.

Then, the operation of the control system of the conventional AC servo motor having such a system configuration will be described with reference to FIG.

2 is a signal waveform diagram showing the mutual relationship between the signals u, v, and w generated from the encoder when the motor rotates clockwise.

Referring to this, in the conventional servo motor control system, the microprocessor 13 (see FIG. 1) reads the state of the v-phase and the w-phase only in the rising (polling) of the u-phase, and sets the current control address. At the points a and d in the waveform diagram, the normal current control address is set. Therefore, if the rising (polling) on u occurs somewhere other than point a or point d, i.e. between point b or c, or between point a and point b, then the rising of phase u (polling) It is an error and therefore the current control address must not be set by the wrong rising (polling). However, in a conventional control system, when an abnormal commutation signal is input by external noise and a rising phase (polling) of the u phase occurs, the current control address is read by reading the state of the v phase and the w phase wherever it occurs. Set to 1 or 1024 unconditionally. As a result, the rotation of the motor becomes abnormal, or if the degree is severe, the motor may be damaged.

The present invention was created to solve the above problems, and even if abnormal signals are generated due to external noise, the commutation of the servo motor drive that can prevent abnormal rotation and damage of the motor by controlling the current of the motor normally. The purpose is to provide an error prevention method.

In order to achieve the above object, a method of preventing a commutation error of a servo motor drive according to the present invention includes: setting a predetermined current control address by reading states of u, v, and w signals generated from an encoder; Setting a predetermined current control address by a microprocessor when the motor rotates after the setting and rises (polling) on u; And counting the position pulse signal from the encoder by the microprocessor. If the current control address according to the counting is slightly different from 1 or 1024, the rising (polling) of the u phase is determined to be normal and the current control address is counted. Is set to 1 or 1024 to control the motor, and if the current control address according to the counting has a relatively large difference from 1 or 1024, the rising (polling) of the u-phase is determined as noise 1 It is characterized by including the step of controlling the motor by the current control address according to the counting, without setting the address or the current control address of 1024 address.

In this way, since the current control address is set by determining whether the rising (polling) of the u phase is normal or caused by noise, there is an advantage of preventing abnormal rotation or damage of the conventional motor.

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

3 and 4 are schematic system flow diagrams of a servo motor drive control system according to the method for preventing commutation errors of the servo motor drive of the present invention.

Referring to these, in the initializing steps 31 and 41, since the power is supplied to the encoder 12 (see FIG. 1) and the motor does not rotate, the rising or falling of the phase of u does not occur, and therefore, the microprocessor 13 By reading the state of v, w, current control address is set as indicated by 'middle address' of FIG. In the state where u phase is 1 and both v phase and w phase are 0 ('section' 1 in FIG. 2), the current control address is set to 512 as shown in the 'current control address'. After the current control address is set in this way, when the motor 11 rotates, a u-phase rising (polling) is generated (32, 42). At this time, the microprocessor 13 reads the v-phase and w-phase, and the v-phase is 0. If w phase is 1, the current control address is set to address 1 (steps 33 to 35), or if v phase is 1 and w phase is 0, the current control address is set to address 1024 (43 to 45). When the motor continues to rotate in this state, the current control address is continuously set to 1 or 1024 at rising (polling) of u phase. At this time, the microprocessor 13 counts 'up' or 'down' at the counter using the position pulse signals A and B generated from the encoder 12 and based on the current control address 1 or 1024. Calculate.

In the above-described series of operations, when noise occurs on the u phase signal among the commutation signals of the encoder 12 and rise (polling) of the u phase occurs, between f and a continuous in the u phase signal waveform diagram of FIG. ('Section' ④) or between a and b ('section' ⑤), the v phase is 0 and the w phase is 1, so the current control address is set to address 1. That is, in section ④ and section ⑤, the current control address is set to address 1 as long as the rising (polling) of u phase occurs. More precisely, the u phase rising (polling) occurs only at the point 'a' in the u phase signal waveform diagram of FIG. 2, and therefore, only the current control address is set to address 1 at this time.

On the other hand, in the present invention, when the rising (polling) of the u phase occurs when noise is included in the u in the sections ④ and ⑤, the rising (polling) of the u phase generated at that time is noise or at a desired rising (position to be generated). The current control address is set by determining whether the generated signal is a point 'a') signal in the signal waveform diagram of the u phase of FIG.

First, when rising (polling) of u phase occurs at the normal point `a '(see FIG. 2), the current control address is set, and when the motor 11 rotates, a position pulse generated by the encoder 12 A and B are counted by the microprocessor 13 and the current control address is calculated and set until the next u phase rise (polling) occurs. That is, in the signal waveform diagram of the u phase of FIG. 2, the current control address is set by the rising (polling) signal of the u phase and the current control address between the points 'a' and 'd'. The microprocessor 13 counts the position pulses A and B generated by the encoder 12 to set the current control address. At this time, the current control address immediately before and after address 1 at the point 'a' where the motor 11 rotates to generate the rising (polling) of u phase (the microprocessor moves the position pulses A and B of the encoder). Set the current control address by counting). On the basis of this fact, when u rise (polling) occurs, the microprocessor 13 counts the position pulses A and B from the encoder 12 before unconditionally setting address 1 or address 1024. If the current control address has a slight difference (△ x) with reference to 1 or 1024, then the rising signal on u generated at that time is considered to be generated at the point 'a' or 'd'. Control address is set. When the rising (polling) of u phase occurs, if the current control address counted by the microprocessor 13 has a value larger than the slight difference (Δx) based on 1 or 1024 addresses, In this case, the motor is controlled by the current control address counted by the microprocessor 13 without setting address 1 or address 1024 (step 46).

As described above, in the method of preventing the commutation error of the servo motor drive according to the present invention, the current control address is set by determining whether the rising (polling) of u phase is normal or caused by noise. There is an advantage that can prevent the damage in advance.

Claims (1)

Reading a state of u, v, w signals generated from an encoder and setting a predetermined current control address; Setting a predetermined current control address by a microprocessor when a rotation (u) of u phase occurs after the setting; And counting the position pulse signal from the encoder by the microprocessor, and if the current control address according to the counting has a slight difference from 1 or 1024, the rising (polling) of the u phase is determined to be normal. The motor is controlled by setting the address to 1 or 1024. If the current control address according to the counting has a relatively large difference with 1 or 1024, the rising (polling) of the u phase is determined as noise. And controlling the motor by the current control address according to the counting, without setting the current control address of the first address or the 1024 address.