KR20130057335A - Commutation signal detecting device and an encoder using the same - Google Patents

Abstract

PURPOSE: A magnetic pole detecting element and an encoder using the same are provided to compatibly apply to a motor having various poles by providing the number of the pole of the motor to a firmware applied to the magnetic pole detecting element. CONSTITUTION: An encoder comprises an encoder element(110), a communication unit(120), and a magnetic pole detecting element(130). The encoder element generates encoder signals indicating rotation positions. The communication unit is respectively connected to the encoder element and the magnetic pole detecting element, thereby transceiving the data between the both elements. The magnetic pole detecting element connected to a pole number setting terminal(140) of a motor receives the encoder signals from the encoder element and generates magnetic pole detecting signals. The magnetic pole detecting element is utilized by being selected from a FPGA(Field-Programmable Gate Array) chip, an ASIC(Application-Specific Integrated Circuit) chip, or a microprocessor chip.

Description

Stimulation detection device and encoder using the same {Commutation signal detecting device and an encoder using the same}

The present invention relates to a magnetic pole detection element and an encoder using the same, and more particularly, magnetic pole detection for generating a magnetic pole detection signal (typically U, V, W signals) used for determining a motor rotation position in a control system. Implement the element and the encoder which adds the stimulus detection element to the incremental encoder which outputs A, B, Z phase signals which are widely used at low cost, and the absolute encoder circuit which outputs the absolute position angle. It is intended to be used as a sensor.

In the servo control system, an apparatus for detecting the position of a rotating motor for position control is called an encoder, and for speed control, the speed is measured by a speed sensor or by using position information measured from an encoder. The speed is also calculated from. As such, the encoder is a core component that senses and provides the position of a rotating motor to a servo system that controls the position or speed of industrial equipment including robots, numerically controlled machine tools, and the like.

Although encoders can be generally classified into optical, magnetic and inductive methods, the encoders related to the present invention can be referred to as a technology applied to all encoders regardless of the method.

For the sake of understanding, in the case of the optical encoder, for example, the basic structure detects the interruption of light passing through the rotating grating from the light emitting element and passing through the rotating grating in the light receiving element. The rotating lattice has slits formed at equal intervals on a glass plate installed on the shaft of the motor. As the rotating lattice rotates with the rotation of the motor, light interruptions occur, resulting in an analog signal in the light receiving element.

On the other hand, optical encoders can be classified into incremental and absolute types. FIG. 1 shows the structure of an incremental encoder used in a control system for a general position sensor.

As shown, the incremental encoders have A and B outputs generated at regular intervals from each other and a Z output generated once per motor revolution. That is, the light beam projected from the light emitting element 1 passes through the slit 3 of the rotating disk 2 and then each of the slits 6, 7, 8 corresponding to A, B, Z of the fixed slit plate 4. It passes through and is detected by the light receiving elements 5 of A, B, and Z. The slits of A and B on the fixed slit plate 4 are arranged to have a phase difference of 90 degrees, and an electric signal output with a waveform maintained also represents a square wave having a phase difference of 90 degrees. The Z-phase outputs a square wave representing one revolution of the encoder.

On the other hand, the absolute encoder has the same configuration and signal generation scheme as the incremental. In absolute encoders, however, the slit of the rotating disk is arranged differently than that of the incremental encoder. The slit is formed by a binary code string, so that the outer circumference of the rotating disk is the least significant bit and the required number of bits (rows) toward the center. Slits are arranged concentrically. Therefore, there is a light receiving element according to the number of bits, and finally the position of the rotation axis is generated by a sign such as binary or binary decimal number.

Therefore, incremental encoders and absolute encoders have different advantages and disadvantages. Incremental encoders are simple in structure, inexpensive, and have a small number of wires that transmit output signals. However, the output pulse of the incremental encoder does not represent the absolute value of the rotational position of the shaft, and the number of pulses proportional to the angle of rotation of the shaft is obtained.The controller accumulates the encoder output pulse on the counter to count the rotation amount and consequently calculates the movement amount. do. Since the amount of rotation is counted continuously, anti-noise measures must be taken during signal transmission. If the power is cut off, the original position cannot be displayed even if the power is turned on again.

On the other hand, since the absolute encoder can detect the absolute position of the input shaft, the error due to noise generated during signal transmission does not accumulate, and even when the power is disconnected and re-input, the original position as the incremental type is used. It is possible to detect the correct current position normally without losing. The disadvantage is that as the number of bits increases, the number of output signal lines increases, making it difficult to miniaturize and lower the cost.

In a system for controlling various types of motors using such an encoder as a sensor, it is sometimes necessary to determine the position of the motor magnetic pole when the motor is started, and to detect the magnetic pole position in order to rotate without irregularities when the motor is rotated. As described above, since a general encoder is provided without a detection function for detecting a magnetic pole, a signal capable of recognizing the position of the motor magnet is additionally required for motor control.

In order to solve the problems of the encoder, various prior arts such as KR 10-0170331 (Samsung Electronics, Prior Art 1), KR 10-0153641 (Hyosung Heavy Industries, Prior Art 2), and KR 10-0293380 (Kang Seok-hee, Prior Art 3) The technology has been filed for registration. However, in the case of the prior art 1, a circuit in which the stimulus detection signals (U, V, W) are output to the incremental encoder chip is included, and the position is detected based on the output information. The price is very high. On the other hand, in the case of the prior art 2, a specific logic circuit is used to generate a Z-phase signal in the forward and reverse directions, and to determine the position of the rotor using the count value of the reverse signal and the count value of the encoder pulse. I adopt it. In the case of the prior art 3, a separate sensor dog and a sensor are installed, and the current position is obtained by using the length of each section of the sensor dog, the number of Z phase pulses and the offset value of each section.

As a result, in the prior art, a method of obtaining a UVW signal using an expensive encoder chip, employing a large number of separate complicated logic circuits, or using a separate sensor and sensor dog to implement a method of obtaining a current position of a motor. However, it is considerably more expensive than conventionally used encoders, and its configuration is complicated by using various logic hardware.

The present invention has been filed to provide a practical device for having a function as an encoder for servo control by utilizing an existing low cost encoder.

That is, the present invention has an object of implementing an encoder for servo that enables servo control by adding an element for detecting a stimulus to a general encoder circuit widely used as a general industrial sensor by implementing an element for detecting a stimulus.

In addition, the present invention has an object to use the firmware to be implanted in the stimulus detection element to be used in various types of motor control by allowing the number of poles of the motor and the signal for stimulus detection to interwork with each other.

In order to achieve the object of the present invention, there is provided a magnetic pole detection element for generating a magnetic pole detection signal by receiving the rotational position signal from the encoder element which is a sensor for detecting the rotational position of the motor.

The encoder further comprises: an encoder element for generating an encoder signal for each phase indicating a rotation position; Communication means implemented in each of the encoder element and the following magnetic pole detection element, the communication means being configured to transmit and receive data between the two elements; And a stimulus detection element connected to the motor pole number setting terminal to receive the number of motor poles and receive a signal from the encoder element to generate a stimulus detection signal.

In addition, the stimulus detection element is selected from among an FPGA chip, an ASIC chip, or a microprocessor chip, and the stimulus detection signal of the stimulus detection element is linked to the number of poles of the motor used. In addition, the communication means is characterized in that the serial communication scheme is adopted.

Further, the magnetic pole detecting element receives the number of poles of the motor from the pole number setting terminal, calculates the machine angle from the encoder pulse transmitted through the communication means, converts the electric angle from the machine angle and the number of motor poles, It comprises a means for generating a stimulus detection signal using the electric angle, characterized in that the electric angle converted from the machine angle is defined as [machine angle * number of poles / 2] mod 360.

As a result, the stimulus detection signals converted from the electric angles generate corresponding U, V, and W signals, respectively, according to the magnitude of the specific electric angle.

The present invention implements an encoder in which a stimulus detection element is added to a low-cost encoder which is a position sensor widely used in a general industrial control system, thereby implementing an encoder having a simple structure and a low cost.

In addition, the present invention provides the number of poles of the motor to be used in the firmware to be implanted in the element for detecting the stimulus, it can be used interchangeably with a motor having a variety of poles, maximizing flexibility and convenience that can be applied to various types It also has the effect.

1 is a structural diagram of an optical encoder used in a servo control system.
2 is a block diagram of an encoder according to the present invention.
3 is a flowchart for generating a stimulus detection signal in the stimulus detection device according to the present invention.
4 is a view showing the relationship between the mechanical angle and the electrical angle calculated in the magnetic pole detection element according to the present invention.
5 is a U, V, W stimulus detection signal calculated and formed based on the electrical angle

The above mentioned problem is solved by the improved encoder of the present invention. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of an encoder according to the present invention.

As illustrated, a stimulus detection device 130 is provided to generate a stimulus detection signal by receiving a rotational position signal from an encoder element 110 which is a sensor for detecting a rotational position of a motor.

That is, the encoder used in the servo control system is composed of an encoder element 110, a communication means 120, and a stimulus detection element 130.

The encoder element 110 generates an encoder pulse signal of each of the A phase 151, the B phase 152, and the Z phase 153. The encoder element 110 is mass produced as a semiconductor chip and is commonly used in most encoders.

On the other hand, the communication means 120 is implemented in each of the encoder element 110 and the following magnetic pole detection element 130 is provided to transmit and receive data between the two elements, the absolute generated by the encoder element 110 The location value is transmitted via the communication means 120. Preferably, the communication means 120 is characterized in that the communication in the serial (serial) communication method.

The magnetic pole detection element 130 is directly connected to receive data from the number of terminals of the motor poles 140, and communicates the position information generated from the encoder element 110 with the communication means 120. The stimulus detection signals U (171), V (172), and W (173) are finally generated.

The stimulus detection device 130 is a hardware device additionally connected to the existing encoder device 110, and may use an FPGA chip or a dedicated ASIC chip equipped with firmware for generating a stimulus detection signal. On the other hand, a stimulus detection signal generation algorithm may be programmed and used in the internal memory of a low-cost microprocessor.

3 is a flowchart of generating a stimulus detection signal in the stimulus detection element 130 of the encoder according to the present invention.

A method of generating a stimulus detection signal performed by the stimulus detection element can be summarized as follows. That is, the pole number of the motor is input from the pole number setting terminal, the machine angle is calculated from the signal transmitted through the communication means, the electric angle is converted from the machine angle and the number of motor poles, and the magnetic pole is detected using the electric angle. Generate a signal.

First, when the power is turned on, the system initialization proceeds and global variables or local variables are reset to prepare the on-board calculation means to be driven (S210).

The encoder device according to the present invention includes a motor pole number setting terminal 140, and scans the terminal to read the value of the corresponding register to recognize the number of poles of the motor in which the encoder is used (S220).

The next step is to recognize the machine angle from the encoder signal input through the communication port 120 (S230). The machine angle is usually in the form of a non-inverted binary code, and can be represented by information from as small as 8 bits to as many as tens of bits.

4 is a view showing the relationship between the mechanical angle and the electrical angle, the mechanical angle means the actual mechanical angle having an angle of 360 degrees in one rotation, the electrical angle is determined differently depending on the number of poles of the magnet mounted on the motor Lose.

That is, in the case of an 8-pole motor, eight magnets (four pairs of N / S magnets) are installed, and when they are unfolded linearly, as shown in FIG. An electric angle that is repeated once is formed, and a mechanical angle that rotates 360 degrees by each rotation of the motor shaft is defined.

The relationship between the electrical angle and the mechanical angle is summarized as follows.

For two-pole motors, the electrical and mechanical angles coincide. Thus electrical angle = mechanical angle.

For 4-pole motors, electrical angle = [machine angle * 2] mod 360.

For 6-pole motors, electrical angle = [machine angle * 3] mod 360.

For 8-pole motors, electrical angle = [machine angle * 4] mod 360.

For N-pole motors, electrical angle = [machine angle * N / 2] mod 360 is defined.

Therefore, the electric angle can be calculated using the motor pole number read from the motor pole number setting terminal 140 and the mechanical angle calculated in step S230 (S240).

The final step generates a U (171), V (172), W (173) signal using the electrical angle calculated above (S250).

FIG. 5 shows U, V, and W stimulus detection signals that are calculated based on the calculated electric angles. The stimulus detection signals are generated by calculating the electric angles calculated in the previous step as the following determination condition.

If electric angle is (0 ~ 180), U phase ---> High

If electrical angle is (! (0 ~ 180)), U phase ---> Low

If electric angle is (120 ~ 300), V phase ---> High

If electrical angle is (! (120 ~ 300)), V phase ---> Low

If electric angle is (! (60 ~ 240)), W phase ---> High

If electric angle is (60 ~ 240), W phase ---> Low

Accordingly, the U, V, and W signals are repeated in steps S230 to S250 according to the change in the input machine angle, thereby forming the continuous U, V, and W waveforms shown in FIG. 5.

As a result, the stimulus detection signal converted from the electric angle can be seen that the corresponding U, V, and W signals are generated according to the magnitude of a specific electric angle, and the stimulus detection signal of the stimulus detection element is used. It can be seen that it is calculated in conjunction with the number of poles of the motor.

As described above, it is possible to implement a control encoder by utilizing a conventional low-cost encoder by adding a stimulus detection element that generates U, V, and W signals to a conventional encoder.

As described above, the encoder according to the present invention is not limited to the above-described embodiment and the accompanying drawings, and it is understood that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those skilled in the art to which the invention pertains.

1: light emitting element 2: rotating disk
3: slit 4: fixed slit plate
5: light receiving element 6,7,8: optical slit
110: encoder element 120: communication means
130: magnetic pole detection element 140: motor pole number setting terminal

Claims (9)

In the sensor element,
A magnetic pole detection element for generating a magnetic pole detection signal by receiving a rotational position signal from a sensor for detecting the rotational position of the motor. The method of claim 1, wherein
And the magnetic pole detection signal is linked to the number of poles of the motor to be used. 3. The method according to claim 1 or 2,
The stimulus detection element
A stimulus detection device characterized in that it is selected from among an FPGA chip, an ASIC chip, or a microprocessor chip. In encoders used in control systems,
An encoder element for generating an encoder signal of each phase indicative of a rotation position;
Communication means connected to each of the encoder element and the following magnetic pole detection element so as to transmit and receive data between the two elements; And
A stimulus detection element connected to a motor pole number setting terminal to receive a motor pole and receive an encoder signal from the encoder element to generate a stimulus detection signal;
An encoder characterized by consisting of. 5. The method of claim 4,
The stimulus detection element
An encoder characterized by being selected from an FPGA chip, an ASIC chip, or a microprocessor chip. 5. The method of claim 4,
And said communication means employs a serial communication scheme. 5. The method of claim 4,
The stimulus detection element,
The pole number of the motor is input from the pole number setting terminal, the machine angle is calculated from the signal transmitted through the communication means, the electric angle is converted from the machine angle and the motor pole number, and the magnetic pole is detected using the electric angle. An encoder characterized in that it comprises a means for generating a signal. 8. The method of claim 7,
The electric angle converted from the machine angle is
Electric angle = [machine angle * number of poles / 2] mod 360
An encoder characterized by a point defined as. 8. The method of claim 7,
The stimulus detection signal converted from the electrical angle is characterized in that the corresponding U, V, and W signals are generated according to the size of a specific electrical angle.

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