A leveling system and a moving stage

Abstract

The present invention relates to a leveling system and a moving stage. It includes: a calculation unit, a control valve, an air isolator, a first type of compensator, and a first type of sensor. The calculation unit is used to calculate the pressure trajectory curve of the isolator according to the centroid change trajectory of the platform. The control valve is respectively connected to the calculation unit and the air isolator, and the control valve is used to control the operation of the air isolator according to the pressure trajectory curve. The first type of sensor is used to obtain the vertical actual position value of the platform. The first type of compensator is connected to the first type of sensor, and the first type of compensator is used to calculate the air pressure value to be compensated according to the difference between the actual position value and the set position value. Since the pressure trajectory curve is calculated in advance, the air isolator can operate according to the pressure trajectory curve, which is beneficial to improving the reaction speed and reaction accuracy. And since the air isolator is used to support the platform, it will not cause excessive heat generation during long-term use. The system of the present application can work stably for a long time.

Description

Technical Field

[0001] The present invention relates to the field of motion platform control, and particularly to a leveling system and a motion stage. Background Art

[0002] In precision semiconductor equipment, especially in a motion stage for precise positioning of workpieces, due to the movement of the moving mass of the motion stage, the centroid of the entire motion stage will change, and the change in the centroid of the motion stage will cause the motion stage to tilt. The traditional solution is to use a mechanical spring plus a vertical force compensation motor to form an active leveling system. This system will actively control the vertical force compensation motor according to the change in the centroid of the motion stage to compensate for the change in the spring force caused by the change in the centroid. Therefore, the response time is determined by the vertical force compensation motor, and the corresponding speed is very fast. However, the problem with this method is that when the moving mass of the motion stage stays at a certain position of the motion stage, the vertical force compensation motor needs to continuously output force, resulting in large heat generation and high power consumption of the vertical force compensation motor. Maintaining this state for a long time will affect the performance of the vertical force compensation motor itself and also the performance of the motion stage. Summary of the Invention

[0003] Based on this, a leveling system is provided, which can work stably for a long time, has a relatively fast reaction speed and less heat generation.

[0004] A leveling system includes: a calculation unit, a control valve, an air isolator, a first type of compensator, and a first type of sensor.

[0005] The calculation unit is used to calculate the pressure trajectory curve of the isolator according to the centroid change trajectory of the platform.

[0006] The control valve is respectively connected to the calculation unit and the air isolator, and the control valve is used to control the operation of the air isolator according to the pressure trajectory curve.

[0007] The first type of sensor is used to obtain the vertical actual position value of the platform.

[0008] The first type of compensator is connected to the first type of sensor, and the first type of compensator is used to calculate the air pressure value to be compensated according to the difference between the actual position value and the set position value.

[0009] Since the pressure trajectory curve is calculated in advance in the above system, the air isolator can operate according to the pressure trajectory curve, which is beneficial to improving the reaction speed and reaction accuracy, and since the air isolator is used to support the platform, it will not cause excessive heat generation during long-term use. The system of the present application can work stably for a long time.

[0010] In one embodiment, the leveling system further includes a second type of sensor, a second type of compensator, and a vertical force compensation motor.

[0011] The second type of sensor is used to obtain the end pressure value of the air isolator.

[0012] The second type of compensator is connected to the second type of sensor, and the second type of compensator is used to calculate the force difference to be compensated according to the end pressure value and the set pressure value.

[0013] The vertical force compensation motor is connected to the second type of compensator, and the vertical force compensation motor is used to output a compensation force, and the magnitude of the compensation force is equal to the force difference.

[0014] In one embodiment, the second type of sensor is a barometric pressure sensor.

[0015] In one embodiment, the calculation unit includes a centroid calculation module and a pressure calculation module. The centroid calculation module is used to calculate the centroid change trajectory of the platform according to the movement trajectory of the platform, and the pressure calculation module is used to calculate the pressure trajectory curve of the isolator according to the centroid change trajectory.

[0016] In one embodiment, the number of the air isolators is multiple, the number of the vertical force compensation motors is the same as the number of the air isolators, and the vertical force compensation motors are arranged in one-to-one correspondence with the air isolators.

[0017] In one embodiment, the first type of sensor is a vertical position sensor.

[0018] In one embodiment, the control valve is a pressure proportional valve.

[0019] A motion stage includes a platform, a motion mechanism is arranged on the platform, and further includes the leveling system, and the platform is supported by the leveling system. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the leveling system according to the embodiment of the present application.

[0021] Figure 2 It is a schematic diagram of the relationship between the centroid of the platform and the output force of each air isolator according to the embodiment of the present application.

[0022] Figure 3 It is a schematic diagram of the designed pressure curve and the actual pressure curve of the air isolator of the leveling system according to the embodiment of the present application.

[0023] Figure 4 It is a schematic diagram of the pneumatic principle of the leveling system according to the embodiment of the present application.

[0024] Figure 5 It is a schematic diagram of the first implementation manner of the leveling system according to the present application.

[0025] Figure 6 Schematic diagram for setting up the platform on the leveling system.

[0026] Figure 7 Schematic diagram of the second implementation manner of the leveling system of the present application.

[0027] Figure 8 Schematic diagram of the third implementation manner of the leveling system of the present application.

[0028] Wherein:

[0029] 110, air isolator; 120, vertical force compensation motor; 130, first type of sensor; 140, control valve; 150, second type of sensor; 200, platform. Detailed implementation manners

[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0031] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0033] As Figure 1 、 Figure 4 、 Figure 5 and Figure 6 shown, the embodiments of the present application provide a leveling system, which includes: a calculation unit, a control valve 140, an air isolator 110, a first type of compensator, and a first type of sensor 130.

[0034] The calculation unit is used to calculate the pressure trajectory curve of the isolator according to the centroid change trajectory of the platform 200.

[0035] The control valve 140 is respectively connected to the computing unit and the air vibration isolator 110, and the control valve 140 is configured to control the operation of the air vibration isolator 110 according to the pressure trajectory curve.

[0036] The first type of sensor 130 is configured to obtain the vertical actual position value of the platform 200.

[0037] The first type of compensator is connected to the first type of sensor 130, and the first type of compensator is configured to calculate the air pressure value to be compensated according to the difference between the actual position value and the set position value.

[0038] When the above system of the present application is in use, the computing unit first calculates the pressure trajectory curve of the vibration isolator. Here, various calculation methods can be applied to calculate the pressure trajectory curve. The above pressure trajectory curve reflects the change in the supporting force that needs to be applied to the platform 200 during the change of the centroid of the corresponding air vibration isolator 110 along with the preset trajectory, that is, when the position of the centroid of the platform 200 changes, the supporting force that the corresponding air vibration isolator 110 needs to output also changes accordingly.

[0039] Specifically, the computing unit includes a centroid calculation module and a pressure calculation module. The centroid calculation module is configured to calculate the centroid change trajectory of the platform 200 according to the preset movement trajectory of the platform 200. That is, the centroid calculation module calculates the correspondence between the centroid of the moving platform and the movement trajectory of the moving platform. After the 3D model of the moving platform is built, the relationship between the centroid of the moving platform and the trajectory of the moving platform can be obtained by measuring the centroid of the moving platform at different positions in the model.

[0040] The pressure calculation module is configured to calculate the pressure trajectory curve of the vibration isolator according to the centroid change trajectory. Since F = PA, where A is the force application area, that is, the force application area of the air vibration isolator 110, and A is a constant value. First, the force values that each air vibration isolator 110 needs to output can be calculated, and then through the above formula, the corresponding required air pressure value can be calculated. Therefore, when the moving platform is about to start running a pre-determined trajectory, the pressure calculation module has already calculated the pressure trajectory curves of each air vibration isolator 110 during the running of this trajectory. When the moving platform starts to run the trajectory, the pressure calculation module transmits the corresponding pressure to the control valve 140 in real time, so as to control the air pressure of each air vibration isolator 110 in real time according to the movement trajectory of the moving platform.

[0041] Specifically, as Figure 2As shown, when calculating the pressure that the corresponding air isolator 110 needs to output when the centroid of the platform 200 is located at a certain position through the following formula. Among them, F1, F2, and F3 are the pressures that each air isolator 110 needs to output. mg is the weight of the centroid. L represents the corresponding moment. Among them, F3 can be the resultant force value of two air isolators 110.

[0042]

[0043]

[0044]

[0045] After each air isolator 110 is determined according to its respective pressure trajectory curve, each control valve 140 is controlled according to the pressure trajectory curve, and then the air pressure of each air isolator 110 is controlled, so that the magnitude of the output force of each air isolator 110 can be accurately controlled. Furthermore, the attitude of the platform 200 can be accurately adjusted through the air isolator 110.

[0046] In this embodiment, the first type of sensor 130 is used to obtain the actual position value in the vertical direction of the platform 200. Relative to the reference plane of the platform 200, the above vertical direction is the direction perpendicular to the reference plane.

[0047] The first type of compensator is connected to the first type of sensor 130, and the first type of compensator is used to calculate the air pressure value that needs to be compensated according to the difference between the actual position value and the set position value. Here, the air pressure difference that needs to be supplemented can be obtained by multiplying the position difference by a coefficient. The above system can be obtained through a limited number of tests according to the actual situation.

[0048] The first type of compensator is also connected to the control valve 140, and the control valve 140 controls the operation of the isolator according to the pressure trajectory curve and the air pressure value that needs to be compensated.

[0049] The above settings form a vertical direction feedback control mechanism for the platform 200. This is beneficial to more accurately control the attitude adjustment of the platform 200.

[0050] In this embodiment, the first type of sensor 130 is a sensor such as a vertical position sensor. The first type of sensor 130 is used to obtain the position information in the vertical direction of the platform 200.

[0051] In this embodiment, the leveling system further includes a second type of sensor 150, a second type of compensator, and a vertical force compensation motor 120.

[0052] The second type of sensor 150 is used to obtain the end pressure value of the air isolator 110.

[0053] The second type of compensator is connected to the second type of sensor 150, and the second type of compensator is configured to calculate the force difference to be compensated based on the end pressure value and the set pressure value.

[0054] The vertical force compensation motor 120 is connected to the second type of compensator, and the vertical force compensation motor 120 is configured to output a compensation force, and the magnitude of the compensation force is equal to the force difference.

[0055] Specifically, the above-mentioned vertical force compensation motor 120 can be a voice coil motor or a linear motor or other types of motors. In this application, the air isolator 110 and the vertical force compensation motor 120 are used in combination. Since the air isolator 110 is driven by gas, there will be a certain hysteresis. As Figure 3 shown, the pressure in the air isolator 110 does not change precisely along the set pressure line, but along the actual pressure line. Due to the pressure difference between the set pressure and the actual pressure, there will be a difference between the actual output force and the theoretical output force of each air isolator 110. At this time, the vertical force compensation motor 120 with rapid and sensitive response can be used to compensate the corresponding force difference. This makes the above-mentioned system of this application respond quickly and sensitively, with less heat generation and stable long-term operation.

[0056] This application has a pressure feedforward control mechanism and a pressure feedback control mechanism. The pressure feedforward control mechanism is mainly implemented by a calculation unit, and the pressure feedback control mechanism is mainly implemented by the second type of sensor 150, the second type of compensator, and the vertical force compensation motor 120.

[0057] When the above-mentioned leveling system is in use, the platform 200 is supported by a plurality of air isolators 110, and each air isolator 110 is equipped with a vertical force compensation motor 120.

[0058] The second type of sensor 150 is used to detect the actual input air pressure value at the end of the air isolator 110. If the detected end pressure value is different from the set pressure value, the force output by the air isolator 110 is insufficient. At this time, the vertical force compensation motor 120 provided on one side of the air isolator 110 can output a compensation force. The magnitude of the specific compensation force can be obtained by the following method: the second type of compensator is configured to calculate the force difference to be compensated based on the end pressure value and the set pressure value. That is, after the air pressure difference is determined, since the force application area of the air isolator 110 is constant, the magnitude of the force to be compensated is also determined, that is, △F = △P * S.

[0059] When the output force of the air isolator 110 reaches the preset value, the vertical force compensation motor 120 no longer outputs a compensation force. Finally, the platform 200 is supported by the air isolator 110.

[0060] In the above - mentioned manner, the attitude adjustment of the platform 200 can be quickly realized to keep the platform 200 in a horizontal state. Moreover, the vertical - force compensation motor 120 only plays an auxiliary compensation role, with low power consumption and little heat generation. Furthermore, finally, the platform 200 is supported by the air isolators 110, rather than by the vertical - force compensation motor 120. Therefore, the situation where the vertical - force compensation motor 120 has excessive heat generation and excessive power consumption will not occur.

[0061] In this embodiment, the second - type sensor 150 can be a sensor for detecting air pressure values, such as a barometric pressure sensor, a pressure sensor, etc.

[0062] In this embodiment, the control valve 140 is a pressure - proportional valve. The operation of the corresponding air isolator 110 can be precisely controlled through the pressure - proportional valve.

[0063] In this embodiment, the number of the air isolators 110 is multiple, the number of the vertical - force compensation motors 120 is the same as that of the air isolators 110, and the vertical - force compensation motors 120 and the air isolators 110 are arranged in one - to - one correspondence.

[0064] The following describes the implementation manners of the present application in detail through specific examples.

[0065] For example, as Figure 5 and Figure 6 shown, 4 air isolators 110 and 4 vertical - force compensation motors 120 are arranged in the vertical direction. Among them, the 4 air isolators 110 are arranged at the four top corners of the welding frame. The stators of the 4 air isolators 110 are connected to the lower welding frame, and the rotors of the 4 air isolators 110 are connected to the lower surface of the marble - material platform 200 of the upper moving table. The 4 vertical - force compensation motors 120 are respectively arranged in one - to - one correspondence with the 4 air isolators 110. The stators of the 4 vertical - force compensation motors 120 are connected to the lower welding frame, and the rotors of the 4 vertical - force compensation motors 120 are connected to the lower surface of the marble platform 200 of the upper moving table. 3 pressure - proportional valves are used to precisely control the air pressure of the 4 air isolators 110, and 1 pressure - proportional valve controls 2 air isolators 110. 3 vertical - position sensors are used to form a position - feedback closed - loop in the vertical direction to precisely control the vertical displacement of the 4 air isolators 110. 3 pressure sensors are used to monitor the actual air pressure of the isolators at the ends close to the air isolators 110 to form an air - pressure feedback closed - loop.

[0066] For example, as Figure 7As shown in the figure, three air vibration isolators 110 and three vertical force compensation motors 120 are arranged in the vertical direction. The stators of the three air vibration isolators 110 are connected to the lower welding frame, and the rotors of the three air vibration isolators 110 are connected to the lower surface of the marble platform 200 of the upper moving table. The stators of the three vertical force compensation motors 120 are connected to the lower welding frame. The rotors of the three vertical force compensation motors 120 are connected to the lower surface of the marble platform 200 of the upper moving table. Three pressure proportional valves are used to precisely control the air pressure of the three air vibration isolators 110. Three vertical position sensors are used to form a vertical position feedback closed loop to precisely control the vertical displacement of the three air vibration isolators 110. Three pressure sensors are used to monitor the actual air pressure of the vibration isolators at the ends near the air vibration isolators 110 to form an air pressure feedback closed loop.

[0067] For example, as Figure 8 shown in the figure, four air vibration isolators 110 and four vertical force compensation motors 120 are arranged in the vertical direction. The layout method of placing the air vibration isolators 110 inside the vertical force compensation motors 120 is adopted, that is, the four vertical force compensation motors 120 are arranged on the outer circle, and the four air vibration isolators 110 are arranged on the inner circle. The advantage of this layout is that the deformation of the marble platform 200 caused by the support of the air vibration isolators 110 is smaller, so that the force that the vertical force compensation motors 120 need to output will be smaller.

[0068] An embodiment of the present application further provides a moving table, which includes a platform 200, a motion mechanism is arranged on the platform 200, and further includes the leveling system, and the platform 200 is supported by the leveling system.

[0069] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0070] The above-described embodiments only represent several implementation manners of the present invention, and the description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A leveling system, characterized in that, Comprising: A calculation unit, a control valve, an air vibration isolator, a first type of compensator, and a first type of sensor, The calculation unit is configured to calculate the pressure trajectory curve of the vibration isolator according to the centroid change trajectory of the platform. The calculation unit includes a centroid calculation module and a pressure calculation module. The centroid calculation module is configured to calculate the centroid change trajectory of the platform according to the preset movement trajectory of the platform, and the pressure calculation module is configured to calculate the pressure trajectory curve of the vibration isolator according to the centroid change trajectory, The control valve is respectively connected to the calculation unit and the air vibration isolator. The control valve is configured to control the operation of the air vibration isolator according to the pressure trajectory curve, The first type of sensor is configured to obtain the vertical actual position value of the platform, The first type of compensator is connected to the first type of sensor. The first type of compensator is configured to calculate the air pressure value to be compensated according to the difference between the actual position value and the set position value, The leveling system further includes a second type of sensor, a second type of compensator, and a vertical force compensation motor, The second type of sensor is configured to obtain the end pressure value of the air vibration isolator, The second type of compensator is connected to the second type of sensor. The second type of compensator is configured to calculate the force difference to be compensated according to the end pressure value and the set pressure value, The vertical force compensation motor is connected to the second type of compensator. The vertical force compensation motor is configured to output a compensation force, and the magnitude of the compensation force is equal to the force difference, When the moving stage is about to start running a pre-determined trajectory, the pressure calculation module has already calculated the pressure trajectory curves of each air vibration isolator during the running of this trajectory. When the moving stage starts running the trajectory, the pressure calculation module transmits the corresponding pressure to the control valve in real time, so as to control the air pressure of each air vibration isolator in real time according to the movement trajectory of the moving stage, When the output force of the air vibration isolator reaches the preset value, the vertical force compensation motor no longer outputs the compensation force. Finally, the air vibration isolator supports the platform. In the above manner, the attitude of the platform is quickly adjusted to maintain the horizontal state of the platform.

2. The leveling system according to claim 1, wherein The second type of sensor is a pressure sensor.

3. The leveling system according to claim 1, characterized in that The number of the air vibration isolators is multiple, the number of the vertical force compensation motors is the same as the number of the air vibration isolators, and the vertical force compensation motors are arranged in one-to-one correspondence with the air vibration isolators.

4. The leveling system according to claim 1, characterized in that, The first type of sensor is a vertical position sensor.

5. The leveling system according to claim 1, wherein The control valve is a pressure proportional valve.

6. A moving platform, comprising a platform, wherein a moving mechanism is arranged on the platform, and is characterized in that, It further includes the leveling system according to any one of claims 1 to 5, and the platform is supported by the leveling system.

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