A method and system for initial position identification of a linear motor with UVW feedback signal

Abstract

This solution discloses a method and system for initial position identification of linear motors with UVW feedback signals. Addressing the problem of linear motors without absolute position feedback being unable to perform normal start-up control, this method and system provides an initial position identification method and system for linear motors with UVW feedback signals. This method is simple, easy to operate, and convenient to implement. Utilizing UVW feedback signals for initial position identification not only enables the identification of the initial position but also solves the requirement that each motor only needs to be identified once. Furthermore, it enables real-time position calibration of the motor during operation, thereby preventing deviations.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of motor control, and particularly relates to a linear motor initial position identification method and system with UVW feedback signals. BACKGROUND

[0002] For an encoder without initial position information, the initial rotor position angle cannot be obtained. The initial position angle needs to be estimated through an algorithm. The accuracy of the rotor initial position estimation directly determines whether the motor can start, the motor operation performance and whether a high-performance control strategy can be implemented. Therefore, whether the rotor initial position can be accurately estimated is a prerequisite for implementing a high-performance control strategy of the motor. Many existing initial position estimation methods are based on a rotating permanent magnet motor and are too complex for a linear motor, depend on motor parameters, and are even not applicable to the linear motor.

[0003] To solve the above technical problems, the applicant proposes a linear motor initial position identification method and control system [application number: 202210444883.X]. The scheme continuously inputs current Id to the direct axis of the linear motor through the current output unit 1, controls the forward or reverse rotation of the permanent magnet mover through the rotation direction determination unit, calculates the feedback angle at this moment through the resolution of the feedback encoder through the angle recording unit, and then determines whether the permanent magnet mover is flipped and stalled, and finally calculates the final identified initial position angle through the initial angle calculation unit according to the recorded angle and the rotation direction determination.

[0004] The above scheme solves the problem that the two end clamping points of the linear motor cannot be accurately identified. The initial position angle of the linear motor can be accurately obtained, the accuracy of the initial position of the permanent magnet mover is high, and the starting and operation performance of the linear motor is improved, and the high-performance control strategy of the linear motor is completed.

[0005] The applicant continues to develop and research based on the previous scheme, and proposes a special initial position identification method and system different from the previous scheme for a linear motor with UVW feedback signals. The new scheme can also achieve the effect of identifying the position of a motor only once. During long-time operation, the position can be calibrated in real time to ensure that the fault problem caused by the deviation of the position information does not occur. SUMMARY

[0006] The purpose of the present application is to provide a linear motor initial position identification method and system with UVW feedback signals to solve the above problems.

[0007] To achieve the above purpose, the present application adopts the following technical scheme:

[0008] A linear motor initial position identification method with UVW feedback signal, comprising the following steps:

[0009] S1. Given the direct axis current Id, the mover is attracted to the position coinciding with the direct axis, and the position information Pos1 and U phase level U_Level_1 of the mover at this moment are recorded;

[0010] S2. Given displacement amount PosCycle, the mover is moved in the positive direction by a displacement amount PosCycle;

[0011] The U phase level is sampled during the movement, and the position information Pos2 of the mover at this moment is recorded when the change of the U phase level is captured;

[0012] When the displacement ends, the position information Pos3 of the mover at this moment is recorded;

[0013] S3. According to the position difference PosError1=Pos3-Pos1 and the given displacement amount PosCycle, it is judged whether the actual displacement amount of the mover meets the given amount, if yes, step S4 is executed, otherwise step S7 is executed;

[0014] S4. According to the position difference PosError2=Pos3-Pos2 and the U phase level U_Level_1, the initial position information is calculated, if the U phase level U_Level_1 is high, step S5 is executed, if the U phase level U_Level_1 is low, step S6 is executed;

[0015] S5. Initial position information PosInt=A-PosError2, step S8 is executed, A represents the position count value of 1 circle;

[0016] S6. Initial position information PosInt=B-PosError2, step S8 is executed, B represents the position count value of 1.5 circles;

[0017] S7. Initial position identification fails, and needs to be re-identified, and the identification this time is ended;

[0018] S8. Initial position identification is successful;

[0019] S9. After each motor stop running, the U phase level U_Level_2 is sampled and recorded, after the motor starts running, the U phase level is sampled, and the position information is calibrated each time the change of the U phase level is captured, and the position compensation value PosComp=PosInt-Pos used for calibration is PosInt, and Pos is the position information of the U phase level.

[0020] The initial position recognition is realized through the above process, and after the initial position recognition is successful, the initial position recognition is not needed for the subsequent use of the motor again, and only the position information of the U phase level and the recognized position information are subtracted and compensated to realize the real-time position calibration. The problem of deviation is avoided while realizing the initial position recognition through simple processing, and the effect is very prominent.

[0021] In the above linear motor initial position recognition method with UVW feedback signals, in step S2, when the rising edge or falling edge of the U phase level is captured during the movement, the position information Pos2 of the mover at this moment is recorded.

[0022] In the above linear motor initial position recognition method with UVW feedback signals, in step S1, the current output unit inputs the current Id to the direct axis of the linear motor to give the given direct axis current Id, and the mover is attracted to the position coinciding with the direct axis.

[0023] In the above linear motor initial position recognition method with UVW feedback signals, in steps S1 and S2, the position information Pos1, Pos2 and Pos3 are recorded by the position information recording unit.

[0024] In steps S3-S6, the position difference PosError1 and PosError2 and the initial position PosInt are calculated by the initial position calculation unit.

[0025] In the above linear motor initial position recognition method with UVW feedback signals, the position information recording unit is connected to the encoder, and the position information is obtained and recorded according to the counting value of the encoder.

[0026] In the above linear motor initial position recognition method with UVW feedback signals, in step S2, the mover is controlled by the position moving unit to move at a stable moving speed for a given displacement amount PosCycle.

[0027] In the above linear motor initial position recognition method with UVW feedback signals, in steps S1, S2, S8 and S9, the U phase level is sampled by the U phase level unit, and the rising edge and falling edge changes of the U phase level are judged.

[0028] In the above linear motor initial position recognition method with UVW feedback signals, in step S9, the position real-time calibration unit calculates the position compensation value according to the recognized initial position information and the U phase level edge information during operation to calibrate the position information.

[0029] In the above linear motor initial position recognition method with UVW feedback signals, the direct axis is the direct axis in the vector algorithm.

[0030] The application discloses a linear motor initial position identification system with UVW feedback signals, which comprises a control module, and the control module comprises a current output unit, a position moving unit, a position information recording unit, a U-phase level unit, an initial position calculation unit and a position real-time calibration unit.

[0031] The current output unit is used for outputting a direct-axis current for the linear motor to attract the movement of a moving part.

[0032] The position moving unit is used for moving the moving part to move to a set position at a stable speed.

[0033] The position information recording unit is used for recording required position information during the identification process.

[0034] The initial position calculation unit is used for calculating the final identified initial position according to the recorded position information.

[0035] The U-phase level unit is used for sampling a U-phase level and judging the rising and falling edge changes of the U-phase level.

[0036] The position real-time calibration unit is used for calculating and adjusting the position information in real time according to the identified initial position information and the U-phase level edge information during operation.

[0037] The application has the advantages that the method and system can be used for the linear motor without absolute position feedback to solve the problem of normal starting control, the method is simple and easy to operate, and the initial position identification is realized by using the UVW feedback signals, so that the initial position identification is realized, the requirement that a motor is identified only once is met, and the real-time calibration position of the motor during operation is further realized, so that the deviation is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The application discloses a linear motor initial position identification and real-time calibration method unit flow chart with UVW feedback signals.

[0039] Figure 2 The application discloses a linear motor initial position identification and real-time calibration method unit flow chart with UVW feedback signals.

[0040] The application discloses a linear motor initial position identification and real-time calibration method unit flow chart with UVW feedback signals. DETAILED DESCRIPTION

[0041] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0042] The scheme discloses a linear motor initial position identification method and system with UVW feedback signals.

[0043] Specifically, the control module comprises a current output unit 1, a position moving unit 2, a position information recording unit 3, a U-phase level unit 4, an initial position calculation unit 5 and a position real-time calibration unit 6.

[0044] The current output unit 1 is used for outputting a direct-axis current for the linear motor to attract the permanent magnet mover to move, for example, outputting a direct-axis current Id for the linear motor to attract the mover to move to a position coinciding with the direct axis, the direct-axis current Id is a direct-axis current when a fixed electric angle is 0, and the current can make the mover move to the position coinciding with the direct axis;

[0045] The position moving unit 2 is used for moving the permanent magnet mover to move to a set position at a stable speed, for example, moving a given displacement amount PosCycle at a stable moving speed.

[0046] The position information recording unit 3 is used for recording required position information in the identification process.

[0047] The initial position calculation unit 5 is used for calculating the final identified initial position according to the recorded position information.

[0048] The U-phase level unit 4 is used for sampling the U-phase level and judging rising and falling edge changes of the U-phase level.

[0049] The position real-time calibration unit 6 is used for calculating and adjusting the position information in real time according to the identified initial position information and the U-phase level edge information in operation.

[0050] As shown in Figure 1 and Figure 2 , the implementation steps of the scheme are as follows:

[0051] S1. The current output unit 1 inputs a direct-axis current Id to the direct axis of the linear motor to give a given direct-axis current Id, and based on the given direct-axis current Id, the permanent magnet mover is attracted to a position coinciding with the direct axis, the position information recording unit 3 records the position information Pos1 of the mover at this moment, and the U-phase level unit 4 records the U-phase level U_Level_1 at this moment.

[0052] S2. The control module gives a displacement amount PosCycle, and the position moving unit 2 controls the mover to move in a positive direction at a stable moving speed by the displacement amount PosCycle, and the displacement amount PosCycle is usually a periodic position count.

[0053] In the process of moving the mover, the U-phase level unit 4 continuously samples the U-phase level, and informs the position information recording unit 3 to record the position information Pos2 of the mover at the moment when the U-phase level is changed for the first time; the change of the U-phase level refers to the change of the U-phase level from low to high or from high to low, i.e. the rising edge or the falling edge;

[0054] When the displacement ends, the position information recording unit 3 records the position information Pos3 of the mover at the moment;

[0055] S3. The initial position calculation unit 5 calculates the position difference PosError1 = Pos3-Pos1, and judges whether the displacement amount of the actual mover movement conforms to the given amount according to the position difference PosError1 and the given displacement amount PosCycle, if yes, step S4 is executed, otherwise step S7 is executed;

[0056] S4. The initial position calculation unit 5 calculates the position difference PosError2 = Pos3-Pos2, and calculates the initial position information according to the position difference PosError2 and the U-phase level U_Level_1.

[0057] Specifically, the high level of the U-phase level U_Level_1 indicates that the falling edge is sampled at the moment, and the low level of the U-phase level U_Level_1 indicates that the rising edge is sampled at the moment, the position information recorded by the rising edge and the falling edge is different, so the calculated value is different. In the present scheme, if the U-phase level U_Level_1 is high, the initial position information is calculated through step S5; if the U-phase level U_Level_1 is low, the initial position information is calculated through step S6;

[0058] S5. The initial position information PosInt = A-PosError2, step S8 is executed, A represents the position count value of 1 circle, and the subtraction of PosError2 can calculate the real position information of the U-phase edge;

[0059] S6. The initial position information PosInt = B-PosError2, step S8 is executed, B represents the position count value of 1.5 circles, and the subtraction of PosError2 can calculate the real position information of the U-phase edge;

[0060] S7. The initial position is identified as a fault, and needs to be re-identified, and the present identification process is ended;

[0061] S8. The initial position is identified successfully, and step S9 is executed to perform real-time calibration of the position information;

[0062] S9. After each time the motor stops running, the U-phase level unit 4 samples and records the U-phase level U_Level_2, after the motor starts running, the U-phase level unit 4 constantly samples the U-phase level U_Level_3, each time the U-phase level changes, the position real-time calibration unit 6 is informed to calibrate the position information once, and the position compensation value used for calibration is PosComp = PosInt-Pos, Pos is the position information of the U-phase level, and PosInt is the initial position information identified. During the movement, as long as the U-phase level changes are sampled, the difference compensation position information is made, and the actual position information is corrected.

[0063] The UVW three-phase signals are feedback signals, the present scheme uses the feedback signals existing in the linear motor itself to realize initial position identification, and only needs to be identified once, without the need to identify once every time the power is turned on. In addition, the present scheme also uses the identified position information as an input parameter to realize real-time calibration of the position, and ensures that there is no fault problem caused by the offset of the position information.

[0064] The present scheme records the position information of the rising edge and the falling edge of the U-phase, and makes a difference between the position information and the displacement position information (i.e. the position of the mover coinciding with the straight shaft), so that the installation position of the U-phase can be known. There are six states of the UVW three-phase signals, 001, 010, 011, 100, 101 and 110, and the installation position of the U-phase can be known to obtain the rough position corresponding to the six states. A cycle angle is 360 degrees, and according to the reading of the state value of UVW, the position information can be roughly judged in which angle range, for example: 001 corresponds to the range of 0-60 degrees, and 010 corresponds to the range of 60-120 degrees. In the subsequent process, according to the rough position information of the UVW three-phase signals when the power is turned on, the initial position when the power is turned on can be known, and through position correction, the accurate position can be corrected.

[0065] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or use similar ways to replace, but will not deviate from the spirit of the present application or exceed the scope defined by the appended claims.

Claims

1. A method for initial position identification of a linear motor with UVW feedback signal, characterized in that, Includes the following steps: S1. Given the direct-axis current Id, attract the mover to a position that coincides with the direct axis, and record the mover's position information Pos1 and U-phase level U_Level_1 at this moment; S2. Given a displacement PosCycle, move the mover in the positive direction by a displacement PosCycle. During the movement, the U-phase level is sampled, and when a change in the U-phase level is detected, the position information Pos2 of the mover is recorded at that moment. After the displacement is completed, record the position information Pos3 of the mover at this moment; S3. Based on the position difference PosError1 = Pos3 - Pos1 and the given displacement PosCycle, determine whether the actual displacement of the mover matches the given amount. If it matches, proceed to step S4; otherwise, proceed to step S7. S4. Calculate the initial position information based on the position difference PosError2=Pos3-Pos2 and the U-phase level U_Level_1. If the U-phase level U_Level_1 is high, proceed to step S5; if the U-phase level U_Level_1 is low, proceed to step S6. S5. Initial position information PosInt=A-PosError2, execute step S8, where A represents the position count value for 1 lap; S6. Initial position information PosInt=B-PosError2, execute step S8, where B represents the position count value of 1.5 laps; S7. Initial position identification is faulty, re-identification is required, end this identification; S8. Initial position identification successful; S9. Sample and record the U-phase level U_Level_2 after each motor stop. After the motor starts running, sample the U-phase level. When a change in the U-phase level is detected, calibrate the position information. The position compensation value used for calibration is PosComp=PosInt-Pos, where Pos is the position information of the U-phase level and PosInt is the initial position information identified.

2. The method for initial position identification of a linear motor with UVW feedback signal according to claim 1, characterized in that, In step S2, when the rising or falling edge of the U-phase level is captured during the movement, the position information Pos2 of the mover at that moment is recorded.

3. The method for initial position identification of a linear motor with UVW feedback signal according to claim 1, characterized in that, In step S1, the current output unit (1) inputs current Id to the direct axis of the linear motor to give the direct axis current Id, and thereby attracts the mover to the position that coincides with the direct axis.

4. The method for initial position identification of a linear motor with UVW feedback signal according to claim 1, characterized in that, In steps S1 and S2, the location information recording unit (3) records the location information Pos1, Pos2 and Pos3; In steps S3-S6, the position difference PosError1, PosError2 and the initial position PosInt are calculated by the initial position calculation unit (5).

5. The method for initial position identification of a linear motor with UVW feedback signal according to claim 4, characterized in that, The location information recording unit (3) is connected to the encoder and obtains and records location information based on the encoder's count value.

6. The method for initial position identification of a linear motor with UVW feedback signal according to claim 1, characterized in that, In step S2, the position moving unit (2) controls the mover to move a given displacement PosCycle at a stable moving speed.

7. The method for initial position identification of a linear motor with UVW feedback signal according to claim 1, characterized in that, In steps S1, S2, S8, and S9, the U-phase level is sampled by the U-phase level unit (4), and the rising and falling edges of the U-phase level are determined.

8. The method for initial position identification of a linear motor with UVW feedback signal according to claim 1, characterized in that, In step S9, the real-time position calibration unit (6) calculates the position compensation value based on the identified initial position information and the U-phase level edge information during operation to calibrate the position information.

9. The method for initial position identification of a linear motor with UVW feedback signal according to claim 1, characterized in that, The straight axis mentioned is the straight axis in the vector algorithm.

10. A linear motor initial position recognition system with UVW feedback signal, characterized in that, The method for identifying the initial position of a linear motor as described in any one of claims 1 to 9 includes a control module, wherein the control module includes a current output unit (1), a position movement unit (2), a position information recording unit (3), a U-phase level unit (4), an initial position calculation unit (5), and a real-time position calibration unit (6), wherein... The current output unit (1) is used to output direct-axis current to the linear motor to attract the movement of the mover. The position moving unit (2) is used to move the mover so that the mover moves to a set position at a stable speed; Location information recording unit (3) is used to record the required location information during the identification process; The initial position calculation unit (5) is used to calculate the final identified initial position based on the recorded position information; U-phase level unit (4) is used to sample the U-phase level and determine the changes in the rising and falling edges of the U-phase level; The real-time position calibration unit (6) is used to calculate and adjust the position information in real time based on the identified initial position information and the U-phase level edge information during operation.

Images