阅读说明：本技术 一种直线电机及三自由度平面运动台 (Linear motor and three-degree-of-freedom planar motion platform ) 是由 罗岩 陆海亮 谢扬 于 2020-08-03 设计创作，主要内容包括：本发明公开了一种三自由度平面运动台,其包括一种直线电机,所述直线电机包括线圈和磁铁,所述线圈和磁铁之间按一定的偏置距离进行偏置定位,使所述直线电机的动子可相对于所述直线电机的定子在与所述直线电机驱动方向的垂直方向运动；还包括可相对移动的平台定子和平台动子,所述平台定子上布置有若干所述直线电机,所述直线电机的磁铁部分固定在所述平台定子上,所述直线电机的线圈部分固定在所述平台动子上；或者,所述直线电机的线圈部分固定在所述平台定子上,所述直线电机的磁铁部分固定在所述平台动子上。本发明的结构精简紧凑、布局效率高、发热少且定位精度高。(The invention discloses a three-degree-of-freedom plane motion platform which comprises a linear motor, wherein the linear motor comprises a coil and a magnet, and the coil and the magnet are offset and positioned according to a certain offset distance, so that a rotor of the linear motor can move in a direction vertical to the driving direction of the linear motor relative to a stator of the linear motor; the linear motor comprises a platform stator and a platform rotor which can move relatively, wherein the platform stator is provided with a plurality of linear motors, the magnet parts of the linear motors are fixed on the platform stator, and the coil parts of the linear motors are fixed on the platform rotor; or the coil part of the linear motor is fixed on the platform stator, and the magnet part of the linear motor is fixed on the platform rotor. The invention has the advantages of compact structure, high layout efficiency, less heat generation and high positioning precision.)

1. A linear motor comprises a coil and a magnet, and is characterized in that: and the coil and the magnet are offset positioned according to a certain offset distance (D), so that the rotor of the linear motor can move in the direction vertical to the driving direction of the linear motor relative to the stator of the linear motor.

2. A three-degree-of-freedom plane motion platform is characterized in that: comprising a linear motor according to claim 1.

3. The three-degree-of-freedom planar motion table according to claim 2, wherein: the linear motor comprises a platform stator (1) and a platform rotor (2) which can move relatively, wherein the platform stator (1) is provided with a plurality of linear motors, the magnet parts of the linear motors are fixed on the platform stator (1), and the coil parts of the linear motors are fixed on the platform rotor (2).

4. The three-degree-of-freedom planar motion table according to claim 2, wherein: the linear motor comprises a platform stator (1) and a platform rotor (2) which can move relatively, wherein the platform stator (1) is provided with a plurality of linear motors, coil parts of the linear motors are fixed on the platform stator (1), and magnet parts of the linear motors are fixed on the platform rotor (2).

5. A three-degree-of-freedom planar motion table according to claim 3 or 4, characterized in that: the linear motors comprise three linear motors, namely a first linear motor (301), a second linear motor (302) and a third linear motor (303), wherein the first linear motor (301) and the second linear motor (302) are oppositely arranged at two sides of the platform rotor (2), are arranged in the X direction of the platform rotor (2), and are used for driving the platform rotor (2) to linearly move in the Y direction; the third linear motor (303) is arranged in the Y direction of the platform mover (2) and used for driving the platform mover (2) to move linearly in the X direction; the first linear motor (301) and the second linear motor (302) drive the platform mover (2) to rotate in the RZ direction together.

6. A three-degree-of-freedom planar motion table according to claim 3 or 4, characterized in that: the linear motors comprise three linear motors, namely a first linear motor (301), a second linear motor (302) and a third linear motor (303), the first linear motor, the second linear motor and the third linear motor (301, 302 and 303) are uniformly arranged on the outer side of the platform rotor (2), the third linear motor (303) is located on the Y direction of the platform rotor (2) and used for driving the platform rotor (2) to linearly move in the X direction, the first linear motor and the second linear motor (301 and 302) drive under the combined action of the platform rotor (2) to linearly move in the Y direction, and the first linear motor, the second linear motor and the third linear motor (301, 302 and 303) drive the platform rotor (2) to rotate in the RZ direction.

7. A three-degree-of-freedom planar motion table according to claim 3 or 4, characterized in that: the linear motors comprise a first linear motor, a second linear motor, a third linear motor and a fourth linear motor (301, 302, 303, 304), wherein the first linear motor and the second linear motor (301, 302) are oppositely arranged at two sides of the platform rotor (2), are arranged in the X direction of the platform rotor (2), and are used for driving the platform rotor (2) to linearly move in the Y direction; the third linear motor and the fourth linear motor (303, 304) are oppositely arranged on the other two sides of the platform rotor (2), arranged in the Y direction of the platform rotor (2) and used for driving the platform stator (1) to linearly move in the X direction; the first linear motor and the second linear motor (301 and 302) or the third linear motor and the fourth linear motor (303 and 304) drive the platform mover (2) to rotate in the RZ direction together.

8. A three-degree-of-freedom planar motion table according to claim 3 or 4, characterized in that: an air bearing (4) is arranged between the platform stator (1) and the platform rotor (2).

9. The three-degree-of-freedom planar motion table according to claim 8, wherein: four air bearings (4) are arranged and are respectively supported around the platform rotor (2).

Technical Field

The invention belongs to the field of semiconductor equipment manufacturing, relates to a micro-operation motion table mechanism, and particularly relates to a three-degree-of-freedom plane motion table.

Background

The existing three-degree-of-freedom plane motion platform (X, Y direction straight motion and RZ direction rotation) generally adopts two layout modes. One is a way of realizing the motion of three degrees of freedom by adopting independent mechanisms respectively and superposing three sets of mechanisms together, as shown in fig. 1, and is realized by superposing a plurality of conventional linear motor mechanisms (the linear motor is increasingly widely applied in the linear transmission field due to the high transmission efficiency of the linear motor compared with a rotating motor), and the structures of the conventional linear motors are shown in fig. 9 and 10; another arrangement is to use a customized planar motor to achieve three degrees of freedom motion, as shown in fig. 2.

Both of these layouts have their own disadvantages:

1) layout for mechanism stacking

Firstly, the final moving part is connected with the base through each layer of mechanism, and the disturbance of each layer of mechanism is transmitted to the final moving part, so that the positioning precision of the platform is poor;

secondly, a stacking mode is adopted, and the size of the platform in the vertical direction is large;

and the parts are many and the structure is complex.

2) Layout for customized planar motors

Firstly, the plane motor is customized, the design period and the delivery period are long, and the structure is complex;

secondly, the planar motor has large heat productivity and low efficiency.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a three-degree-of-freedom plane motion table which is simple and compact in structure, high in layout efficiency, less in heat generation and high in positioning accuracy.

Another object of the present invention is to provide a linear motor for implementing the three-degree-of-freedom planar motion of the motion stage.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a linear motor comprises a coil and a magnet, wherein the coil and the magnet are offset positioned according to a certain offset distance, so that a rotor of the linear motor can move in a direction perpendicular to the driving direction of the linear motor relative to a stator of the linear motor.

A three-degree-of-freedom planar motion platform comprises a platform stator and a platform rotor which can move relatively, wherein a plurality of linear motors are arranged on the platform stator, magnet parts of the linear motors are fixed on the platform stator, and coil parts of the linear motors are fixed on the platform rotor; or the coil part of the linear motor is fixed on the platform stator, and the magnet part of the linear motor is fixed on the platform rotor.

Further, an air bearing is arranged between the platform stator and the platform rotor.

Furthermore, four air bearings are arranged and are respectively supported around the platform rotor.

The working principle of the invention is as follows:

the invention adopts a linear motor to drive a platform rotor of a planar motion platform, and adopts a mode of offsetting and positioning the linear motor rotor and a stator by several millimeters to ensure that the motor rotor can move relative to the stator in a direction vertical to the driving direction of the motor, thereby realizing the planar motion (micro motion) of the platform in the X, Y and RZ directions. However, the offset positioning of the coil and the magnet of the linear motor in the present invention results in a reduction in the overlapping area of the coil and the magnet. Since F = B · I · L · N, which is a simplified formula for calculating the linear motor force, where F is the motor thrust, B is the magnetic field strength, I is the current in the coil, L is the effective length of the coil in the magnetic field B, and N is the number of coil turns, the coil and magnet offset positioning is equivalent to reducing L so that the motor thrust will be correspondingly reduced.

Aiming at the problem, the invention adopts the following method to solve the problem: the change of the motor output when the coil and the magnet are positioned in a biased mode in the same input current is measured through an experiment, a curve of the relation between the coil bias and the change of the thrust constant is obtained, the measured curve is used as a compensation curve to be input into a control system in advance when a motor control algorithm is designed, and therefore the motor coil and the magnet have constant thrust when the coil and the magnet are biased at different distances, and accurate and stable control is achieved.

Meanwhile, the rotor of the invention isolates the interference of the outside world, and the invention can realize the positioning precision of nanometer level by matching with a high-precision measurement system. As shown in fig. 3, the solid straight line represents the change in the motor constant when the magnet and coil of the linear motor are positioned in an offset manner, and the imaginary straight line represents the change in the corresponding compensation current in the compensator. The current change corresponds to the motor constant change one by one, thereby realizing stable control. Fig. 8 is a simplified control schematic diagram of the present invention, where the experimentally measured curve is stored in a look-up table, and the sensor detects the offset distance between the coil and the magnet and then transmits the information to the look-up table, so as to compensate the corresponding current value into the control loop.

Advantageous effects

Compared with the prior art, the three-degree-of-freedom plane motion platform has the following beneficial effects:

1. the invention adopts a mode of offsetting and positioning the linear motor rotor and the stator by a plurality of millimeters to ensure that the motor rotor can move relative to the stator in a direction vertical to the driving direction of the motor, thereby realizing the planar motion (micro motion) of the platform in the X, Y and RZ directions.

2. The four standard linear motors are adopted to drive the platform rotor, so that the customizing time is saved, the uncontrollable risk of customization is reduced, and the development period is greatly shortened. Meanwhile, because the linear motor is adopted, an additional coil is not needed, and therefore the layout efficiency is higher and the heat generation is less compared with a planar motor.

3. Compared with the existing layout adopting a laminated structure, the structure of the invention is simpler. Because there is not any mechanical connection between platform active cell and the platform stator, consequently can completely cut off external interference, reach higher positioning accuracy. Meanwhile, because the laminated structure is not arranged, the size of the invention in the vertical direction is smaller, and the structure is more compact.

4. In particular, the invention adopts a special compensation control algorithm to ensure that the motor has constant thrust output under the condition of changing thrust constant.

Drawings

Fig. 1 is a schematic structural diagram of a three-degree-of-freedom motion stage implemented by a mechanism stacking layout in the prior art.

Fig. 2 is a schematic diagram of a customized planar motor implemented three-degree-of-freedom motion stage product in the prior art.

Fig. 3 is a schematic diagram of a thrust constant variation curve of the motor in the invention.

Fig. 4 is a schematic structural diagram of an embodiment of a three-degree-of-freedom planar motion stage according to the present invention.

FIG. 5 is a side view of the embodiment disclosed in FIG. 4.

Fig. 6 is a schematic structural diagram of another embodiment of a three-degree-of-freedom planar motion stage according to the present invention.

FIG. 7 is a side view of the embodiment disclosed in FIG. 6.

Fig. 8 is a simplified control schematic of the present invention.

Fig. 9 is a schematic structural diagram of a linear motor in the prior art.

Fig. 10 is a sectional view taken along line a-a in fig. 9.

Fig. 11 is a mechanism diagram of the linear motor in the present invention.

Fig. 12 is a sectional view taken along line B-B in fig. 11.

FIG. 13 is a schematic structural diagram of a three-degree-of-freedom planar motion stage of the present invention, which is driven by three linear motors; fig. 13(a) is a schematic diagram of a magnet part fixed on a platform stator and a coil part fixed on a platform mover, and fig. 13(b) is a schematic diagram of a magnet part fixed on a platform mover and a coil part fixed on a platform stator.

FIG. 14 is a schematic structural diagram of another embodiment of the three-degree-of-freedom planar motion stage of the present invention, which is driven by three linear motors; fig. 14(a) is a schematic diagram of a magnet part fixed on a platform stator and a coil part fixed on a platform mover, and fig. 14(b) is a schematic diagram of a magnet part fixed on a platform mover and a coil part fixed on a platform stator.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.