A method and implementation device for reducing motor tracking error based on micro-drive unit

Abstract

The present invention relates to the field of mechanical precision manufacturing technology, and specifically to a method and an implementation device for reducing motor tracking errors based on a micro-drive unit. A method for reducing motor tracking errors based on a micro-drive unit is specifically that the motor mover is a working output end, and the sensor feeds back the position information of the motor mover to the micro-drive controller in real time; the micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover; the tracking error of the motor mover after displacement compensation is corrected, and the corrected tracking error information is fed back to the motor controller. The error reduction method and implementation device in the present invention reduce the motor tracking error and solve the problem of coupling interference. In addition, the use of single position feedback reduces production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical precision manufacturing, and in particular to a method for reducing motor tracking errors based on a micro-drive unit and an implementation device thereof. Background Art

[0002] With the advancement of technology, the performance of products is improving, and the corresponding product processing accuracy requirements are also getting higher and higher. Among them, motors are widely used in various manufacturing and processing equipment, such as laser cutting machines, machine tools, semiconductor manufacturing equipment, etc.

[0003] At present, the motor system has mechanical / electrical parameter uncertainty, thrust fluctuation, nonlinear friction and other problems, resulting in large position tracking errors in the motor mover movement process. The stroke of the high-precision feed motion platform in existing equipment is generally short, and the accuracy of ordinary macro motion equipment with large stroke cannot meet the actual needs. If a dedicated large-stroke high-precision motion equipment is used, the manufacturing cost of the product will increase significantly. Therefore, the current method mainly combines the general precision macro motion and the high-precision small-stroke micro motion to achieve large-stroke high-precision feeding to reduce tracking errors.

[0004] However, in the prior art, micro-motion is used as the output working end to achieve higher tracking accuracy. The workpiece is placed on the micro-motion part. After the micro-motion part reaches the expected position, the controller drives the micro-motion part to compensate for the displacement of the macro-motion part. However, this compensation method does not reduce the tracking error of the motor mover. At the same time, the macro-micro motion system requires dual position feedback, which will also increase the detection cost of the absolute sensor. In addition, in actual applications, for the feeding of large workpieces, the workpiece is placed on the micro-motion platform, and the mass of the micro-motion part cannot be ignored. When performing displacement compensation, the micro-motion will produce coupling interference to the macro-motion that is difficult to eliminate, increasing the complexity of the macro-motion controller and worsening the trajectory accuracy. Summary of the invention

[0005] In view of the problems of large motor tracking error and coupling interference in the prior art, the present invention provides a method for reducing motor tracking error based on a micro-drive unit and an implementation device.

[0006] A method for reducing motor tracking error based on a micro-drive unit, wherein the motor mover is a working output end, and a sensor feeds back position information of the motor mover to a micro-drive controller in real time;

[0007] The micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover;

[0008] The tracking error of the motor mover after displacement compensation is corrected, and the corrected tracking error information is fed back to the motor controller.

[0009] Optionally, the micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover, specifically including: determining the driving direction and driving amount of the micro-drive unit, the micro-drive unit including a piezoelectric actuator, and extending or shortening the length of the piezoelectric actuator according to the determined driving direction and driving amount to perform displacement compensation on the motor mover.

[0010] Optionally, the driving amount is calculated using the following expression:

[0011]

[0012] Among them, D i is the i-th drive of the motor mover by the micro-drive unit, e i is the sampling error of the i-th transmission cycle, D max is the maximum driving amount of the micro drive unit to the motor mover, D min It is the minimum driving amount of the micro drive unit on the motor mover.

[0013] Optionally, the correction of the tracking error of the motor mover after displacement compensation is specifically as follows:

[0014]

[0015] Among them, E i (e i ) is the corrected feedback error of the motor controller in the i-th transmission cycle.

[0016] A device for implementing a method for reducing motor tracking errors based on a micro-drive unit, comprising a base, a micro-drive unit, a motor assembly, a micro-drive controller connected to the micro-drive unit, a motor controller connected to the motor assembly, and a sensor mounted on the base, wherein the micro-drive unit and the motor assembly are both arranged on the base;

[0017] The motor assembly includes a motor mover, the motor mover is used to place a workpiece, and the sensor is used to feed back position information of the motor mover to the micro-drive controller;

[0018] The micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover, and corrects the compensated tracking error of the motor mover and feeds it back to the motor controller.

[0019] Optionally, the micro-drive unit includes a piezoelectric actuator, an elastic component and an auxiliary mass block, the elastic component is arranged between the motor mover and the auxiliary mass block, the piezoelectric actuator is respectively connected to the motor mover and the auxiliary mass block, and the piezoelectric actuator is used for displacement compensation of the motor mover.

[0020] Optionally, the sensor is an absolute grating ruler.

[0021] Optionally, the motor assembly further includes a guide rail, a slider and a motor stator, the slider is slidably mounted on the guide rail, and the motor mover and the micro-drive unit are arranged on the slider.

[0022] Optionally, an absolute grating encoder is also provided on the base.

[0023] Optionally, the piezoelectric actuator is a piezoelectric ceramic actuator.

[0024] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0025] The present invention uses the motor mover as the working output end, and after the position information of the motor mover is fed back to the micro-drive controller in real time, the micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover, and corrects the tracking error after the displacement compensation of the motor mover. The tracking error fed back to the motor controller is corrected. The present application achieves the reduction of tracking error and solves the problem of coupling interference. At the same time, the single position feedback adopted reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 A flowchart of a method for reducing motor tracking error based on a micro-drive unit provided in Embodiment 1 of the present invention;

[0028] Figure 2 A schematic diagram of the compensation principle of a micro-drive unit provided in the first embodiment of the present invention;

[0029] Figure 3 A tracking error variation diagram provided in the first embodiment of the present invention;

[0030] Figure 4 A schematic diagram of a device for implementing a method for reducing motor tracking errors based on a micro-drive unit provided in Embodiment 2 of the present invention.

[0031] Illustration: micro drive unit 1, auxiliary mass block 11, elastic component 12, piezoelectric actuator 13, motor assembly 2, motor mover 21, motor stator 22, sensor 23, guide rail 24, absolute grating encoder 25, base 3 DETAILED DESCRIPTION

[0032] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it is to be understood that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally disposed component. When a component is considered to be "disposed on" another component, it may be directly disposed on the other component or there may be a centrally disposed component.

[0034] In addition, terms such as "long", "short", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention. They do not indicate or imply that the device or component referred to must have this specific direction or operate with a specific direction structure, and should not be understood as a limitation of the present invention.

[0035] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0036] Embodiment 1

[0037] See also Figures 1 to 3 This embodiment provides a method for reducing the motor tracking error based on a micro-drive unit, with the motor mover as the working output end, and the sensor feeds back the position information of the motor mover to the micro-drive controller in real time; the micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover; the tracking error of the motor mover after displacement compensation is corrected, and the corrected tracking error information is fed back to the motor controller.

[0038] Specifically, in this embodiment, the workpiece can be placed on the motor mover, with the motor mover as the working output end. This method can directly reduce the tracking error of the motor mover. After the sensor feeds back the position information of the motor mover, the micro-drive controller drives the micro-drive unit to perform displacement compensation according to the feedback information. Since displacement compensation will affect the output of the motor controller to produce a suitable control amount, in order to avoid the interference effect of displacement compensation on the motor, the tracking error of the compensated motor mover is corrected. Finally, the corrected tracking error value is fed back to the motor controller to drive the motor assembly to move.

[0039] In specific operations, the micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover, and needs to determine the drive direction and drive amount of the micro-drive unit. In an optional embodiment, the micro-drive unit includes a piezoelectric actuator, and the length of the piezoelectric actuator is extended or shortened according to the determined drive direction and drive amount to compensate for the displacement of the motor mover. The piezoelectric actuator can directly convert electrical energy into mechanical energy. When the voltage is changed, it can be extended or shortened, and can achieve movement in the sub-nanometer range. Therefore, high-precision movement can be achieved, and the compensation working output end can achieve higher position accuracy. Specifically, the drive amount of the micro-drive unit is determined by calculation using the following expression:

[0040]

[0041] Among them, D i is the i-th drive of the motor mover by the micro-drive unit, e i is the tracking error of the ith transmission cycle, D max is the maximum driving amount of the micro drive unit to the motor mover, D min It is the minimum driving amount of the micro drive unit on the motor mover.

[0042] See also Figure 2 Schematic diagram of compensation principle of micro-drive unit. The uncompensated trajectory is the actual motion trajectory of the motor mover without compensation. The reference trajectory is the ideal motion trajectory of the motor mover without tracking error. The difference between the reference trajectory and the compensation trajectory of the current transmission cycle can determine the driving direction and driving amount of the next transmission cycle, which are pre-set in the micro-drive controller. Optionally, if the difference is positive, the motor mover is driven to move right, and if the difference is negative, the motor mover is driven to move left. In the implementation of this method, due to the servo calculation and transmission cycle of the motor system, the micro-drive unit does not perform driving in the first transmission cycle, but performs the i-1th drive in the i-th transmission cycle. Specifically, in the i-th transmission cycle, the difference between the driving amount limit and the previous driving amount of the micro-drive unit for the motor mover and the actual tracking error e of the motor mover are equal. i The actual compensation drive amount D is determined by the relationship i , when e i When the value exceeds the limit value that the micro-drive unit can drive and the driving value of the i-1th time, the driving amount that can be driven in the i-th transmission cycle is the limit value D max or D min On the contrary, the amount that can be driven in the i-th transmission cycle is the amount D of the i-1th drive cycle. i-1 Add the tracking error value e of the ith time i .

[0043] After compensation by the micro-drive unit, the tracking error value of the motor rotor is iIf the tracking error after the above compensation is reduced i Direct feedback to the motor controller will cause the electromagnetic thrust of the motor to fluctuate, resulting in unstable motion of the workbench, that is, coupling interference. In order to stabilize the motion of the motor, the compensated tracking error value needs to be corrected and fed back to the motor controller. The tracking error of the motor mover after displacement compensation is corrected as follows:

[0044]

[0045] Among them, E i (e i ) is the feedback error fed back to the motor controller after correction in the i-th transmission cycle.

[0046] In the implementation of this method, for the first two transmission cycles (i≤2), the feedback error of the motor controller is equal to the tracking error E i (e i )=e i When i>2, the feedback error of the motor controller is the sum of the tracking error and the current drive amount of the micro-drive unit.

[0047] In summary, this embodiment provides a method for reducing motor tracking errors based on a micro-drive unit, with the motor mover as the working output end. After receiving the position information feedback of the motor mover, the micro-drive controller drives the micro-drive unit to perform displacement compensation on the motor mover, and corrects the tracking error after displacement compensation and feeds it back to the motor controller, solving the problems of large tracking errors and coupling interference in the current prior art. In addition, the macro-micro system of this application adopts single position feedback, which greatly reduces the cost of sensor detection.

[0048] Embodiment 2

[0049] See also Figure 4 , this embodiment 2 provides a device for reducing the motor tracking error based on a micro-drive unit, which is used to implement the motor tracking error reduction method of embodiment 1, and specifically includes a base 3, a micro-drive unit 1, a motor assembly 2, a micro-drive controller (not shown) connected to the micro-drive unit 1, a motor controller (not shown) connected to the motor assembly 2, and a sensor 23 installed on the base 3, wherein the micro-drive unit 1 and the motor assembly 2 are both arranged on the base 3; the motor assembly 2 includes a motor mover 21, a workpiece is placed on the motor mover 21, and the sensor 23 is used to feed back the position information of the motor mover 21 to the micro-drive controller; the micro-drive controller controls the micro-drive unit 1 to perform displacement compensation on the motor mover 21, and corrects the compensated tracking error of the motor mover and feeds it back to the motor controller.

[0050] In an optional embodiment, the micro-drive unit 1 includes a piezoelectric actuator 13, an elastic component 12 and an auxiliary mass block 11, the elastic component 12 is arranged between the motor mover 21 and the auxiliary mass block 11, the piezoelectric actuator 13 is respectively connected to the motor mover 21 and the auxiliary mass block 11, and the piezoelectric actuator 13 is used for displacement compensation of the motor mover 21. Optionally, the piezoelectric actuator 13 is a piezoelectric ceramic actuator. Optionally, the elastic component 12 is an elastic component such as a spring, elastic rubber, etc., preferably a high-rigidity spring with higher stiffness. The high-rigidity spring presets a preload force to press the piezoelectric ceramic actuator onto the motor mover 21. When the micro-drive controller confirms the driving amount, it changes the voltage of the piezoelectric ceramic actuator to extend or shorten the length of the piezoelectric ceramic actuator. The length of the piezoelectric ceramic actuator changes, generating a driving force acting on the elastic component 12, and the motor mover 21 and the auxiliary mass block 11 move. The motor mover 21 moves to a predetermined position, thereby achieving displacement compensation for the motor mover 21, and the motor mover 21 achieves higher position accuracy.

[0051] In an optional embodiment, the sensor 23 is an absolute grating ruler. In addition, an absolute grating encoder is also provided on the base 3 for measuring the displacement value of the motor mover 21 .

[0052] In an optional embodiment, the motor assembly 2 further includes a guide rail 24, a slider and a motor stator 22, the slider is slidably mounted on the guide rail 24, and the motor mover 21 and the micro-drive unit 1 are arranged on the slider. The macro motion and the micro motion share the same motor stator 22, and the motor mover 21 and the micro-drive unit 1 are driven to achieve motions with different strokes, which has a simple structure and simplifies the production process.

[0053] In summary, by applying the method and device of the embodiment of the present invention, the position information is fed back through the sensor 23, the micro-drive controller receives the information and responds, controls the micro-drive unit 1 to perform displacement compensation on the motor mover 21, and corrects the compensated tracking error and feeds it back to the motor controller to realize the normal operation of the motor, thereby simplifying the structure of the motor, reducing the motor tracking error and solving the problem of coupling interference. In addition, the use of a single position feedback reduces production costs.

[0054] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reducing motor tracking error based on a micro-drive unit, characterized in that: The micro-drive unit and the motor mover are arranged on the base, the motor mover is the working output end, and the sensor feeds back the position information of the motor mover to the micro-drive controller in real time; The micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover; The tracking error of the motor mover after displacement compensation is corrected, and the corrected tracking error information is fed back to the motor controller.

2. The method for reducing motor tracking error based on a micro-drive unit according to claim 1, characterized in that: The micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover, specifically including: determining the driving direction and driving amount of the micro-drive unit, the micro-drive unit including a piezoelectric actuator, and extending or shortening the length of the piezoelectric actuator according to the determined driving direction and driving amount to perform displacement compensation on the motor mover.

3. The method for reducing motor tracking error based on a micro-drive unit according to claim 2, characterized in that: The driving amount is calculated using the following expression: Among them, D i is the i-th drive of the motor mover by the micro-drive unit, e i is the sampling error of the i-th transmission cycle, D max is the maximum driving amount of the micro drive unit to the motor mover, D min It is the minimum driving amount of the micro drive unit on the motor mover.

4. The method for reducing motor tracking error based on a micro-drive unit according to claim 3, characterized in that: The correction of the tracking error of the motor mover after displacement compensation is specifically as follows: Among them, E i (e i ) is the corrected feedback error of the motor controller in the i-th transmission cycle.

5. A device for implementing a method for reducing motor tracking error based on a micro-drive unit, characterized in that: It includes a base, a micro-drive unit, a motor assembly, a micro-drive controller connected to the micro-drive unit, a motor controller connected to the motor assembly, and a sensor installed on the base, wherein the micro-drive unit and the motor assembly are both arranged on the base; The motor assembly includes a motor mover, the motor mover is used to place a workpiece, and the sensor is used to feed back position information of the motor mover to the micro-drive controller; The micro-drive controller controls the micro-drive unit to perform displacement compensation on the motor mover, and corrects the compensated tracking error of the motor mover and feeds it back to the motor controller.

6. The device for implementing the method for reducing motor tracking error based on a micro-drive unit according to claim 5, characterized in that: The micro-drive unit includes a piezoelectric actuator, an elastic component and an auxiliary mass block, the elastic component is arranged between the motor mover and the auxiliary mass block, the piezoelectric actuator is connected to the motor mover and the auxiliary mass block respectively, and the piezoelectric actuator is used for displacement compensation of the motor mover.

7. The device for implementing the method for reducing motor tracking error based on a micro-drive unit according to claim 5, characterized in that: The sensor is an absolute grating ruler.

8. The device for implementing the method for reducing motor tracking error based on a micro-drive unit according to claim 5, characterized in that: The motor assembly further comprises a guide rail, a slider and a motor stator. The slider is slidably mounted on the guide rail, and the motor mover and the micro-driving unit are arranged on the slider.

9. The device for implementing the method for reducing motor tracking error based on a micro-drive unit according to claim 7, characterized in that: An absolute grating encoder is also arranged on the base.

10. The device for implementing the method for reducing motor tracking error based on a micro-drive unit according to claim 6, characterized in that: The piezoelectric actuator is a piezoelectric ceramic actuator.

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