A control method for a multi-zero signal quadrature encoder

Abstract

The present invention provides a control method for a multi-zero-point signal orthogonal encoder, comprising the following steps: selecting a corresponding pulse accumulation mode and a pole pair number mode according to the rotation angle; setting a desired zero point position through an orthogonal encoder controller; and finally setting a Z-phase zero-point signal pulse width to remain unchanged within a certain speed through an orthogonal encoder counting mode to ensure pulse width stability. The present invention realizes the adaptation of multi-pole-pair motors and dynamic correction of multi-line motors through the control method of a multi-zero-point signal orthogonal encoder, and improves the accuracy of position reading for different working conditions.

Description

Technical Field

[0001] The invention relates to the technical field of orthogonal encoder control, and in particular to a control method for a multi-zero signal orthogonal encoder. Background Art

[0002] The encoder is a sensor installed on the motor to measure the motor's rotation angle and speed. The most commonly used encoder is the orthogonal encoder, which determines the motor's rotation direction and speed by outputting three sets of square wave pulses A, B and Z. There is a 90° phase difference between the A and B phase pulse outputs, so the rotation direction can be determined based on the timing phase relationship of the two signals, and the speed and displacement can be measured based on the number of A and B phase pulse signals; the Z phase is the zero point signal, which is used for reference point positioning after one mechanical cycle. When the encoder rotates to the zero point, the Z signal will send a pulse indicating that it is now at the zero position, which can be used to record the number of encoder rotations, so as to know the running distance. Due to the simple principle and structure of the orthogonal encoder, strong anti-interference ability and high reliability, it is widely used in the field of motors.

[0003] Traditional orthogonal encoders use a single zero-point control method. During the processing of the single-chip microcomputer, the more pulses there are, the greater the impact on the chip processing. That is, when counting in quadrature, disturbances will occur, resulting in frame loss. The single zero-point control method can only be corrected once in a mechanical cycle, which will cause inaccurate position reading and large errors. In addition, if the motor has multiple pole pairs, only the mechanical angle can be corrected during correction, not the electrical angle. The few methods on the market that use multiple zero-point control have relatively large limitations in setting methods.

[0004] The present invention proposes a control method for a multi-zero signal quadrature encoder to achieve the adaptation of multi-pole motors and dynamic correction of multi-line motors, including two control modes: pulse accumulation mode and pole pair mode. The pulse accumulation mode uses multi-zero signal and dynamic correction to make the position reading more accurate; the pole pair mode can flexibly select the control mode according to the motor pole pair number to achieve multi-pole electrode angle correspondence. Summary of the invention

[0005] Purpose of the invention: In order to solve the problem that the current encoder control method has low adaptability to multi-pole motors and the dynamic correction of multi-line motors is unstable, the present invention provides a control method for a multi-zero signal quadrature encoder, including two control modes: pulse accumulation mode and pole pair mode. The pulse accumulation mode uses multi-zero signal and dynamic correction to make the position reading more accurate; the pole pair mode can flexibly select the control mode according to the number of motor poles to achieve multi-pole electrode angle correspondence.

[0006] Technical solution: A control method for a multi-zero signal quadrature encoder, the use method includes the following steps:

[0007] S1: Select the corresponding pulse accumulation mode and pole pair mode according to the motor pole pair number, rotation angle and encoder frequency multiple;

[0008] S2: Run pulse accumulation mode. When the mechanical angle is less than or equal to 360°, set the output of the correction zero point signal after the pulse accumulation reaches a certain number;

[0009] S3: Run the pole pair number mode. When the mechanical angle is greater than 360°, obtain the current pole pair number of the motor and input it into the orthogonal encoder controller. The orthogonal encoder generates a zero point signal with the same pole pair number, and the number of A-phase and B-phase signal pulses generated between each zero point signal is consistent.

[0010] S4: Set the desired zero position of the motor through the orthogonal encoder controller;

[0011] S5: Through the orthogonal encoder counting mode, when the number of pulses reaches a certain number, the rising edge of the B phase is no longer used as the action reference of the falling edge of the Z phase zero point signal.

[0012] The method for determining the encoder frequency multiplication number in step S1 is as follows: when the encoder counts, only the rising edge acts, then there is no frequency multiplication; when the single-phase pulse rises and falls, it acts, then it is 2 times the frequency; when all the rising edges of the orthogonal pulse act, then it is 2 times the frequency; when all the rising edges and falling edges of the orthogonal pulse act, then it is 4 times the frequency.

[0013] The pulse accumulation mode in step S2 works as follows: the 1024-line orthogonal encoder, in the 4x frequency mode, generates a zero-point signal for correction every 1024 pulses to ensure that the rotation is less than one mechanical cycle, and multiple zero-point signals can be generated for correction.

[0014] The pole pair mode in step S3 works as follows: a 1024-line orthogonal encoder is used for an n-pole motor. In the 4x frequency mode, a zero point signal is generated every 1024 / n pulse signals, that is, a zero point signal is generated every 360° electrical cycle, ensuring that multiple zero point signals are generated for correction within one mechanical cycle.

[0015] In step S4, the desired zero point position is set, the initial zero point position of the encoder is set by the orthogonal encoder controller, and the zero point signal generation position is set to be consistent with the rising edge of the A phase or the direction in which the motor sweeps across the α axis.

[0016] In the step S5, the counting mode of the encoder is used to set the number of pulses per unit time or the rotation angle per unit time, and a certain rotation speed is set to control the pulse width of the Z-phase zero point signal. When the motor speed is less than the set speed, the rising edge of the A-phase pulse is used as the reference for the rising edge of the Z-phase pulse, and the rising edge of the B-phase pulse is used as the reference for the falling edge of the Z-phase pulse; when the motor speed is greater than the set speed, the rising edge of the A-phase pulse is used as the reference for the rising edge of the Z-phase pulse, and the falling edge of the A-phase pulse is used as the reference for the falling edge of the Z-phase pulse, so as to ensure that the Z-phase pulse width remains unchanged within a certain speed.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0018] 1. The present invention proposes a multi-zero signal quadrature encoder control method to realize dynamic correction of multi-line motors. Compared with the traditional single zero control method, multiple corrections can be performed when the motor rotates less than one mechanical cycle in the case of frequency doubling, making the position reading more accurate.

[0019] 2. The present invention proposes a multi-zero-point signal orthogonal encoder control method to achieve the adaptation of multi-pole motors. Compared with the traditional orthogonal encoder control method, while ensuring the angle accuracy, when the multi-pole motor rotates more than 360°, it ensures that the motor mechanical angle corresponds to the electrical angle, and ensures that multiple zero-point signals are generated within one mechanical cycle for correction, thereby improving the correction accuracy.

[0020] 3. In the Z signal pulse width control method of the present invention, the Z signal pulse width is set to remain unchanged within a certain rotation speed, thereby improving the accuracy of A phase pulse detection and ensuring the stability of Z phase pulse width. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of the present invention;

[0022] Figure 2 This is an example diagram of the A-phase, B-phase, and Z-phase pulses in the pulse accumulation mode of the present invention;

[0023] Figure 3 This is an example diagram of A-phase, B-phase, and Z-phase pulses in the pole pair mode of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0025] A control method for a multi-zero signal quadrature encoder, such as Figure 1 As shown, the following steps are included:

[0026] Step S1: Select the corresponding pulse accumulation mode and pole pair mode according to the motor pole pair number, rotation angle and encoder frequency multiple;

[0027] Step S2: Pulse accumulation mode: when the mechanical angle is less than or equal to 360°, it is set that when the pulse accumulation reaches a certain number, the correction zero point signal is output;

[0028] Step S3: Pole pair number mode: When the mechanical angle is greater than 360°, the current pole pair number of the motor is obtained and input into the orthogonal encoder controller. The orthogonal encoder generates a zero point signal with the same pole pair number, and the number of A-phase and B-phase signal pulses generated between each zero point signal is consistent;

[0029] Step S4: Setting the motor's corresponding desired zero position by using an orthogonal encoder controller;

[0030] Step S5: Set the counting mode through the orthogonal encoder, and set that when the number of pulses reaches a certain number, the rising edge of the B phase is no longer used as the action reference of the falling edge of the Z phase zero point signal.

[0031] Furthermore, in the method for determining the encoder frequency multiplication number in step S1, when the encoder counts, only the rising edge acts, then there is no frequency multiplication; when the single-phase pulse rises and falls, it acts at 2 times the frequency; when all the rising edges of the orthogonal pulse act at 2 times the frequency; when all the rising edges and falling edges of the orthogonal pulse act at 4 times the frequency;

[0032] Furthermore, the specific working mode of the pulse accumulation mode in step S2 is, for example: a 1024-line orthogonal encoder has a line number of 1024×4=4096 in a 4x frequency mode, that is, 4096 pulses are generated when rotating one mechanical cycle, and a zero point signal can be generated every 1024 pulses for correction, ensuring that even if the rotation is less than one mechanical cycle, multiple zero point signals can be generated for correction, thereby improving the position reading accuracy when the rotation angle is small;

[0033] Further, the specific working mode of the pole pair mode in step S3 is, for example: a two-pole motor, a 1024-line encoder, and a line number of 1024×4=4096 in a 4x frequency mode, that is, 4096 pulses are generated when rotating one mechanical cycle, and a zero point signal can be generated every 512 pulse signals, that is, a zero point signal is generated every 360° electrical cycle, to ensure that multiple zero point signals are generated for correction within multiple mechanical cycles;

[0034] Furthermore, in step S4, the desired zero position of the motor is set, and the initial zero position of the encoder is set by setting the orthogonal encoder controller. Usually, the zero signal generation position is set to be consistent with the rising edge of the A phase or the direction in which the motor sweeps across the α axis;

[0035] Further, in step S5, the encoder's own timing mode is used to set the number of pulses per unit time or the rotation angle per unit time, that is, to set a certain speed to control the pulse width of the Z-phase zero-point signal. When the motor speed is less than the set speed, the rising edge of the A-phase pulse is used as the reference for the rising edge of the Z-phase pulse, and the rising edge of the B-phase pulse is used as the reference for the falling edge of the Z-phase pulse; when the motor speed is greater than the set speed, the rising edge of the A-phase pulse is used as the reference for the rising edge of the Z-phase pulse, and the falling edge of the A-phase pulse is used as the reference for the falling edge of the Z-phase pulse, so as to ensure that the Z-phase pulse width remains unchanged within a certain speed, thereby ensuring the pulse width stability;

[0036] like Figure 2 In the pulse accumulation mode shown, the orthogonal encoder with 1024 lines has a line number of 1024×4=4096 in the 4x frequency mode. If the motor rotates only 180°, a zero point correction signal can be generated every 256 pulses to ensure that multiple zero point corrections can be performed even when the mechanical cycle is less than one circle, thereby improving the position reading accuracy.

[0037] like Figure 3 In the pole pair mode shown, a two-pole motor, and a 1024-line encoder, the line number in the 4x frequency mode is 1024×4=4096 (i.e., 4096 pulses are generated when rotating one mechanical cycle). It is possible to generate a zero point signal every 512 pulse signals to ensure that multiple zero point signals are generated within multiple mechanical cycles for correction.

Claims

1. A control method for a multi-zero signal quadrature encoder, the use method comprising the following steps: S1: Select the corresponding pulse accumulation mode and pole pair mode according to the motor pole pair number, rotation angle and encoder frequency multiple; S2: When the mechanical angle is less than or equal to 360°, the pulse accumulation mode is run, and the correction zero point signal is output when the pulse accumulation reaches a certain number; S3: When the mechanical angle is greater than 360°, the pole pair number mode is run to obtain the current pole pair number of the motor and input it into the orthogonal encoder controller. The orthogonal encoder generates a zero point signal with the same pole pair number, and the number of A-phase and B-phase signal pulses generated between each zero point signal is consistent. S4: Set the desired zero position of the motor through the orthogonal encoder controller; S5: Through the counting mode of the encoder, set the number of pulses per unit time or the rotation angle per unit time, and set a certain speed to control the pulse width of the Z-phase zero signal. When the motor speed is less than the set speed, the rising edge of the A-phase pulse is used as the reference for the rising edge of the Z-phase pulse, and the rising edge of the B-phase pulse is used as the reference for the falling edge of the Z-phase pulse; when the motor speed is greater than the set speed, the rising edge of the A-phase pulse is used as the reference for the rising edge of the Z-phase pulse, and the falling edge of the A-phase pulse is used as the reference for the falling edge of the Z-phase pulse, to ensure that the Z-phase pulse width remains unchanged within a certain speed.

2. The control method of a multi-zero signal quadrature encoder according to claim 1, characterized in that: The method for determining the encoder frequency multiplication number in step S1 is as follows: when the encoder counts, only the rising edge acts, then there is no frequency multiplication; when the single-phase pulse rises and falls, it acts, then it is 2 times the frequency; when all the rising edges of the orthogonal pulse act, then it is 2 times the frequency; when all the rising edges and falling edges of the orthogonal pulse act, then it is 4 times the frequency.

3. The control method of a multi-zero signal quadrature encoder according to claim 1, characterized in that: The pulse accumulation mode in step S2 works as follows: the 1024-line orthogonal encoder, in the 4x frequency mode, generates a zero-point signal for correction every 1024 pulses to ensure that the rotation is less than one mechanical cycle, and multiple zero-point signals can be generated for correction.

4. The control method of a multi-zero signal quadrature encoder according to claim 1, characterized in that: The pole pair mode in step S3 works as follows: a 1024-line orthogonal encoder is used for an n-pole motor. In the 4x frequency mode, a zero point signal is generated every 1024 / n pulse signals, that is, a zero point signal is generated every 360° electrical cycle, ensuring that multiple zero point signals are generated for correction within one mechanical cycle.

5. The control method of a multi-zero signal quadrature encoder according to claim 1, characterized in that: In step S4, the desired zero point position is set, the initial zero point position of the encoder is set by the orthogonal encoder controller, and the zero point signal generation position is set to be consistent with the rising edge of the A phase or the direction in which the motor sweeps across the α axis.

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