CN114963997A - Method and device for measuring and compensating displacement error of workbench in high-precision equipment - Google Patents

Abstract

The invention provides a method and a device for measuring and compensating displacement errors of a workbench in high-precision equipment, wherein the method comprises the steps of arranging at least 3 non-collinear displacement sensors on a movable carrying disc, measuring the projection distance from the movable carrying disc to a reference platform, and forming a virtual plane A at an initial position and a virtual plane B in motion; calculating a rotation angle c of the movable load carrying disc relative to the reference platform in the non-motion direction according to the virtual plane A and the virtual plane B; acquiring height deviations h of any 2 different positions on the movable carrying disc; calculating the displacement deviation in the moving carrying disc in the moving process according to a formula c h or sinc h, namely the displacement checking of the workbench; and the displacement deviation of the workbench is eliminated through an error compensation structure positioned between the workbench and the movable carrying disc. The method and the device designed by the invention can accurately detect and compensate the angle error generated by the workbench in the motion process so as to avoid the limitation of high-precision equipment space and the cost.

Description

Method and device for measuring and compensating table displacement error in high-precision equipment

technical field

The invention belongs to the field of micro-nano manufacturing, and relates to a displacement error measurement technology during the movement of a displacement table, in particular to a method and a device for measuring and compensating the displacement error of a table in high-precision equipment.

Background technique

In the fields of micro-nano manufacturing, optical alignment and other fields, with the rapid development of mechanical manufacturing, metrology science, material science and other disciplines and technologies, it is required to further improve the operating speed and operating efficiency of the workbench on the basis of ensuring the micro-nano level positioning accuracy. , motion stroke, but in practical applications, angular errors such as pitch and/or roll may occur when the worktable moves, which in turn causes the position of the horizontal plane of the worktable to change, which will directly affect the optical alignment, measurement and processing of products. accuracy, etc.

Among the current high-precision equipment, there are devices that use laser interferometers to measure errors. For example, Chinese patent CN103940348A discloses a device and method for multi-degree-of-freedom detection of table motion errors. It needs to install a reflector that reflects the laser light source. The light is adjusted for many times in the optical path, and interference fringes are generated in the detector, and then the interference fringes are processed to obtain the current deflection and displacement of the worktable. The above detection device adopts the laser light source, but the cost of the laser light source is expensive and requires a certain space in the equipment. In order to install a reflector and avoid the laser light path, the detection device is bulky and difficult to integrate into the equipment. There are also devices that use an electronic inclinometer, or a combination of an electronic inclinometer and a laser interferometer for error measurement, but the resolution of the electronic inclinometer can only reach micron-level accuracy, which is far from meeting the needs of precision measurement and processing. .

SUMMARY OF THE INVENTION

In order to accurately detect and compensate the angle error generated by the worktable of the high-precision equipment during the movement process, and avoid the limitation of the space of the high-precision equipment and the cost of construction, the invention discloses a measurement and compensation of the displacement error of the worktable in the high-precision equipment method and device.

The technical scheme for realizing the purpose of the invention is as follows:

In a first aspect, the present invention discloses a method for measuring and compensating the displacement error of a worktable in a high-precision device, comprising the following steps:

At least 3 non-collinear displacement sensors are arranged on the mobile carrier;

The displacement sensor is used to collect the projection distance between the mobile carrier plate and the reference platform below it in real time, and the measurement points of each displacement sensor are connected in sequence to form a virtual plane;

Obtain the virtual plane A where the mobile carrier is at the initial position, and the virtual plane B during the movement;

Calculate the rotation angle c of the virtual plane B relative to the virtual plane A, that is, to obtain the rotation angle of the worktable and the moving carrier plate relative to the reference platform in the non-moving direction;

Obtain the height deviation h between any two different positions on the moving carrier plate during the movement;

According to the formula c*h or sinc*h, calculate the displacement deviation of the moving carrier plate during the movement process, that is, the displacement deviation of the worktable;

Drive the error compensation structure between the worktable and the moving carrier plate to eliminate the displacement deviation of the worktable in real time.

The method designed by the invention can quickly and efficiently calculate the displacement deviation in the non-moving direction generated by the worktable in the process of following the moving carrier plate relative to its initial position, and at the same time, the generated displacement error can be corrected in time through the error compensation structure. Eliminate, so that the actual working surface of the workbench is highly consistent with the working surface at its initial position, so as to ensure the machining accuracy of the load on the workbench.

In a first improved embodiment of the above method, the method for acquiring the virtual plane is: using displacement sensors to acquire the projection distance between each displacement sensor and its vertical projection point on the reference platform in real time; according to each displacement sensor and its projection distance, After they are connected in sequence, a virtual plane of the mobile carrier plate relative to the reference platform is formed.

In a second improved embodiment of the above method, among the displacement sensors on the upper surface of the moving carrier, a part of the displacement sensors are distributed along the movement direction of the worktable, and the other part of the displacement sensors are distributed along the movement direction perpendicular to the worktable.

In a third improved embodiment of the above method, the rotation angle c includes the pitch angle β along the movement direction of the parallel worktable, and the displacement deviation of the worktable is the pitch displacement deviation β*h or sinβ*h;

In a further improvement of the above method and the third improved embodiment, the rotation angle c includes the roll angle θ along the movement direction of the vertical table, and the roll displacement deviation of the table is displacement deviation θ*h or sinθ*h.

In the second aspect, the present invention discloses a device for measuring and compensating the displacement error of the worktable in high-precision equipment. The mobile carrier plate is arranged on the guide mechanism of the reference platform, and the mobile carrier plate is provided with a worktable.

The device includes an error compensation structure and at least three displacement sensors, and the displacement sensors and the error compensation structure are all electrically connected to the controller.

Displacement sensors are distributed on the moving carrier plate and are used to collect the vertical projection distance between the moving carrier plate and the reference platform.

The controller is used to calculate the displacement deviation of the worktable and the movement of the carrier plate in the non-moving direction, and is used to output displacement adjustment instructions.

The error compensation structure is located between the worktable and the moving carrier plate, and is used to eliminate the displacement deviation of the worktable in the non-moving direction according to the adjustment instruction.

In an embodiment of the above device, among the at least three displacement sensors, a part of the displacement sensors are distributed along the movement direction of the worktable, and the other part of the displacement sensors are distributed along the movement direction perpendicular to the worktable.

Further, there are four displacement sensors mentioned above, which are respectively located at the four corners of the moving carrier plate.

Further, the above-mentioned displacement sensor includes any one of a spectral confocal sensor, a point laser, a capacitive sensor, and an eddy current sensor.

In another embodiment of the above device, the table displacement deviation includes a pitch displacement deviation in a non-moving direction, and/or a roll displacement deviation in the non-moving direction.

Compared with the prior art, the beneficial effects of the present invention are: the method and device for measuring and compensating the displacement error of the worktable designed by the present invention can firstly avoid the space caused by arranging the reflective structure in the device; secondly, The use of displacement sensors instead of laser sensors can greatly reduce the manufacturing cost of the equipment; in the third aspect, the device designed in the present invention is especially suitable for high-precision equipment and can greatly improve the processing of workpieces (such as substrate exposure, overlay engraving, optical component follow-up alignment) etc.) accuracy.

Description of drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that are used in the description of the embodiments.

Fig. 1 is the flow chart of the method for measuring and compensating the displacement error of the table in the high-precision equipment in the embodiment 1;

FIG. 2 is a schematic structural diagram of a device for measuring and compensating table displacement errors in high-precision equipment;

Among them, 1. reference platform; 2. displacement sensor; 3. error compensation structure; 4. worktable; 5. moving carrier plate; 6. guiding mechanism.

Detailed ways

The present invention will be further described below with reference to specific embodiments, and the advantages and characteristics of the present invention will become clearer with the description. However, these examples are only exemplary and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention can be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the protection scope of the present invention.

Example 1:

This embodiment provides a method for measuring and compensating a table displacement error in a high-precision device. In this embodiment, referring to FIG. 1 and FIG. 2 , FIG. 1 is a flowchart of a method for measuring and compensating for a table displacement error. In the figure, 2 is the reference platform, 2 is the displacement sensor, 3 is the error compensation structure, 4 is the worktable, 5 is the moving carrier plate, and 6 is the guiding mechanism.

As shown in Figure 1, the method for measuring and compensating the table displacement error includes the following steps:

S1. At least three non-collinear displacement sensors are arranged on the mobile carrier plate.

In this step, the positions of the at least three displacement sensors on the upper surface of the moving carrier plate 5 can be set on the same straight line along the movement direction or the vertical movement direction, or can be arbitrarily set along other directions. In this embodiment, a part of the displacement sensors are distributed along the moving direction of the worktable, and the other part of the displacement sensors are distributed along the moving direction of the vertical worktable. The purpose of this setting is: when the worktable 4 moves to different positions, the projection distance between the mobile carrier plate 5 and the reference platform 1 is obtained through the displacement sensor 2 on each displacement sensor, and a virtual plane can be formed after each displacement sensor is connected, and then It is convenient to calculate the angle change that occurs during the movement of the workbench 4 .

S2. Use displacement sensors to collect the projection distance between the mobile carrier plate and the reference platform below it in real time, and connect the measurement points of each displacement sensor in sequence to form a virtual plane.

S3. Acquire the virtual plane A where the mobile carrier is at the initial position, and the virtual plane B during the movement.

In this step S2 and S3, the acquisition method of the virtual plane is: using the displacement sensor 2 to acquire the projection distance between each displacement sensor 2 and its vertical projection point on the reference platform 1 in real time; according to each displacement sensor 2 and its projection distance, After they are connected in sequence, a virtual plane of the moving tray 5 relative to the reference platform 1 is formed.

S4. Calculate the rotation angle c of the virtual plane B relative to the virtual plane A, that is, to obtain the rotation angle of the worktable and the moving carrier plate relative to the reference platform in the non-moving direction.

In this step, the value of the displacement sensor 2 will keep changing during the power movement process, so the virtual plane B will also keep changing relative to the virtual plane A, which will generate a certain rotation angle c, which will cause the worktable to have a Displacement in the non-motion direction.

Specifically, the rotation angle c is calculated according to the change amount of the displacement sensor and the distance between the displacement sensors using the existing general method, which will not be described in detail here.

S5. Acquire the height deviation h between two different positions on the moving carrier plate during the movement.

In this step, if the rotation angle of the moving carrier plate changes during the movement (either one or both of the pitch angle and the roll angle), the heights of different positions on the moving carrier plate will also change accordingly, so that When the height deviation h is generated, the offsets of two different positions on the moving carrier plate 5 can be calculated by combining the angle between the virtual plane A and the virtual plane.

S6. According to the formula c*h or sinc*h, calculate the displacement deviation of the moving carrier plate during the movement process, that is, the displacement deviation of the worktable.

In steps S4 to S6, as shown in FIG. 1, the worktable 4 is located above the moving carrier plate 5. When the moving carrier plate 5 moves relative to the reference platform 6, it may be in the direction of movement (also referred to as the Y direction or the first direction). direction), a pitch angle occurs, or a roll angle occurs in the vertical motion direction (also known as the X direction or the second direction), or the angle changes in both directions, thereby causing the working surface of the workbench 4 to be different from the Inconsistency of the working face in the initial state.

In one method of steps S4 and S5, during the movement of the moving carrier plate 5, when there is only a pitch angle relative to the reference platform 6, that is, the rotation angle c is the pitch angle β parallel to the movement direction of the table, at this time The worktable only produces a pitch displacement deviation along the movement direction (ie, the Y direction or the first direction), which is β*h or sinβ*h.

In another method of steps S4 and S5, when the moving carrier plate 5 moves to the working position, when it only has a tumbling angle relative to the reference platform 6, the rotation angle c is the tumbling angle θ perpendicular to the movement direction of the table, At this time, the table only produces a rolling displacement deviation along the vertical movement direction (ie, the X direction or the second direction), which is θ*h or sinθ*h.

In the third method of steps S4 and S5, when the moving carrier plate 5 moves to the working position, when the roll angle and the pitch angle occur simultaneously with respect to the reference platform 6, that is, the rotation angle c includes a direction parallel to the movement direction of the table. The pitch angle β and the roll angle θ along the vertical motion direction of the worktable, at this time, the worktable is generated in both the motion direction (ie the Y direction or the first direction) and the vertical motion direction (ie the X direction or the second direction) The displacement deviations are θ*h and β*h (or sinβ*h and sinθ*h).

S7. Drive the error compensation structure located between the worktable and the moving carrier plate to eliminate the displacement deviation of the worktable in real time.

In this step, as described with reference to FIG. 2 , since the moving carrier plate moves along the track or the guide mechanism on the reference platform, in this step, through the function of the error compensation structure, the worktable above the moving carrier plate is performed according to the calculated displacement deviation. Reverse compensation to eliminate changes in the working surface of the table caused by changes in the angle of the moving carrier.

The method designed in this embodiment can quickly and efficiently calculate the displacement error generated by the worktable relative to its initial position when it follows the moving carrier plate to move to different work positions, and at the same time, through the action of the error compensation structure, the generated displacement error can be corrected in time. Eliminate it so that the actual working surface of the worktable keeps the same height as the working surface at its initial position, so as to ensure the machining accuracy of the load on the worktable.

Example 2:

This embodiment provides a method for measuring and compensating the displacement error of a worktable in a high-precision device. The difference between this embodiment and Embodiment 1 is:

In step S1, at least two displacement sensors are arranged on the moving carrier plate, and the at least two displacement sensors are located on the same straight line along the moving direction of the parallel worktable or along the moving direction of the vertical worktable.

In step S2, each displacement sensor is connected in sequence to form a virtual straight line of the moving carrier plate relative to the reference platform, and the virtual straight line C of the worktable at the initial position and the virtual straight line D of the working position are obtained.

In step S4, the rotation angle c between the virtual straight line C and the virtual straight line D is calculated.

In step S5, according to the formula c*h or sinc*h, the displacement deviation of the worktable in the non-moving direction is calculated. At this time, there are two kinds of displacement deviations. When the reference platform 6 only has a pitch angle, that is, the rotation angle c is the pitch angle β along the movement direction of the parallel table, at this time, the table only produces a pitch displacement deviation along the movement direction (ie, the Y direction or the first direction), and The displacement deviation c is β*h or sinβ*h; the other is: during the movement of the moving carrier plate 5, when there is only a tumbling angle relative to the reference platform 6, the rotation angle c is the tumbling along the movement direction of the vertical table The included angle θ, at this time, the table only produces a rollover displacement deviation along the vertical movement direction (ie, the X direction or the second direction), and the displacement deviation c is θ*h or sinθ*h.

The method designed in this embodiment can quickly and efficiently calculate the displacement error generated by the worktable relative to its initial position when it follows the moving carrier plate to move to different work positions, and at the same time, through the action of the error compensation structure, the generated displacement error can be corrected in time. Eliminate it so that the actual working surface of the worktable keeps the same height as the working surface at its initial position, so as to ensure the machining accuracy of the load on the worktable.

Example 3:

This embodiment discloses a device for measuring and compensating the displacement error of a worktable in a high-precision device, which can measure and compensate the displacement error of the worktable in a high-precision device by using the methods in Embodiment 1 and Embodiment 2. As shown in FIG. 2 , in the high-precision equipment, the mobile carrier plate 5 is arranged on the guide mechanism 3 of the reference platform 1, and the mobile carrier plate 5 is provided with a worktable 4, and the mobile carrier plate 5 moves on the guide mechanism 3 to adjust the work. The position of the table 4, the load on the table 4 is moved to the processing position.

As shown in Fig. 2, the device for measuring and compensating the displacement error of the worktable includes an error compensation structure 3 and at least three displacement sensors 2. The displacement sensor 2 and the error compensation structure 3 are both electrically connected to the controller, and the controller can be externally installed or installed In the workbench 4, it is not limited here.

As shown in FIG. 2 , the displacement sensors 2 are distributed on the moving carrier plate 5 , and are used to collect the vertical projection distance between the moving carrier plate 5 and the reference platform 1 .

In order to be able to obtain the vertical projection distances of the moving carrier plate 5 relative to the different positions of the reference platform 1, to obtain the offset caused by the pitch angle generated by the moving carrier plate 5 along the movement direction of the table, and the resulting vertical table movement For the offset caused by the roll angle generated by the direction, in this embodiment, a part of the displacement sensors 2 are distributed along the movement direction of the worktable, and the other part of the displacement sensors 2 are distributed along the movement direction perpendicular to the worktable. Preferably, as shown in FIG. 2 , there are four displacement sensors 2 in this embodiment, and they are respectively located at the four corners of the moving carrier plate 5 .

In this embodiment, any displacement sensor among spectral confocal sensors, point lasers, capacitive sensors, and eddy current sensors can be selected according to factors such as high-precision equipment, distribution spacing, resolution, installation space, and cost.

In this embodiment, the controller is used to calculate the displacement deviation of the worktable and to output the displacement adjustment command for moving the carrier plate in the non-moving direction.

In this embodiment, the table displacement deviation includes the pitch displacement deviation in the non-moving direction and/or the roll displacement deviation in the non-moving direction. Refer to the description in Embodiment 1 for the pitch displacement deviation and the roll displacement deviation.

As shown in FIG. 2 , the error compensation structure 3 is located between the worktable 4 and the moving carrier plate 5, and is used to eliminate the displacement deviation of the worktable according to the adjustment command output by the controller, so that the actual working surface of the worktable remains at its initial position The height of the working surface is the same at all times to ensure the machining accuracy of the load on the working table. The error compensation structure 3 can be selected as a micro-moving table. It should be noted that: in this embodiment, the error compensation structure 3 can adjust the worktable 4 so that the height of the work surface when the worktable 4 is at the working position and the initial position can be adjusted. It only needs to be consistent, and no specific limitation is made here.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention. within the scope of protection.

In addition, it should be understood that although this specification is described in terms of embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims (9)

1. a method for measuring and compensating table displacement error in high-precision equipment, is characterized in that: comprise the following steps: At least 3 non-collinear displacement sensors are arranged on the mobile carrier; The displacement sensor is used to collect the projection distance between the mobile carrier plate and the reference platform below it in real time, and the measurement points of each displacement sensor are connected in sequence to form a virtual plane; Obtain the virtual plane A where the mobile carrier is at the initial position, and the virtual plane B during the movement; Calculate the rotation angle c of the virtual plane B relative to the virtual plane A, that is, to obtain the rotation angle of the worktable and the moving carrier plate relative to the reference platform in the non-moving direction; Obtain the height deviation h between any two different positions on the moving carrier plate during the movement; According to the formula c*h or sinc*h, calculate the displacement deviation of the moving carrier plate during the movement process, that is, the displacement deviation of the worktable; Drive the error compensation structure between the worktable and the moving carrier plate to eliminate the displacement deviation of the worktable in real time. 2. method according to claim 1, is characterized in that: the acquisition method of virtual plane is: The displacement sensor is used to obtain the projection distance between each displacement sensor and its vertical projection point on the reference platform in real time; According to the displacement sensors and their projection distances, they are connected in sequence to form a virtual plane of the moving carrier plate relative to the reference platform. 3 . The method according to claim 1 , wherein among the displacement sensors on the moving carrier plate, a part of the displacement sensors are distributed along the movement direction of the worktable, and the other part of the displacement sensors are distributed along the movement direction perpendicular to the worktable. 4 . 4 . The method according to claim 1 , wherein the rotation angle c includes the pitch angle β along the movement direction of the worktable, and the displacement deviation of the worktable is the pitch displacement deviation β*h or sinβ*h. 5 . 5. The method according to claim 1 or 4, characterized in that: the rotation angle c includes the roll angle θ along the vertical table movement direction, and the displacement deviation of the table is the roll displacement deviation θ*h or sin θ*h . 6. A device for measuring and compensating the displacement error of a worktable in a high-precision equipment, the mobile carrier plate is arranged on the guide mechanism of the reference platform, and the mobile carrier plate is provided with a worktable, characterized in that: the device comprises an error compensation structure and a At least 3 displacement sensors, the displacement sensors and the error compensation structure are all electrically connected to the controller; The displacement sensors are distributed on the moving carrier plate, and are used to collect the vertical projection distance between the moving carrier plate and the reference platform; The controller is used to calculate the displacement deviation of the worktable and the moving carrier plate in the non-moving direction, and is used to output the displacement adjustment instruction; The error compensation structure is located between the worktable and the moving carrier plate, and is used to eliminate the displacement deviation of the worktable according to the adjustment instruction. 7 . The device for measuring and compensating worktable displacement error according to claim 6 , wherein among the at least three displacement sensors, a part of the displacement sensors is distributed along the movement direction of the worktable, and the other part of the displacement sensors is distributed along the movement direction of the worktable. 8 . Distributed along the vertical table movement direction. 8 . The device for measuring and compensating worktable displacement error according to claim 7 , wherein there are four displacement sensors, and they are respectively located at four corners of the moving carrier plate. 9 . 9. The device for measuring and compensating worktable displacement error according to claim 6, wherein the worktable displacement deviation comprises pitch displacement deviation in the non-moving direction, and/or rolling in the non-moving direction displacement deviation.

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