CN103176270B - Two-degree-of-freedom high-speed parallel scanning platform and perpendicularity error calibration method thereof - Google Patents

Abstract

The invention relates to a two-degree-of-freedom high-speed parallel scanning platform and a method for calibrating the verticality error thereof, comprising a casing, a linear drive mechanism installed in the casing, a reflector shaft mechanism, a joint bearing and a PSD position sensor. A two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention adopts a single-mirror structure, and only one reflection is needed to complete the scanning work, avoiding the error amplification effect caused by double-mirror reflection. At the same time, the present invention adopts a two-input and two-output structure, which is much easier to control than the prior art; it also adopts a joint bearing structure, which can have greater rigidity and deflection angle; and because a two-dimensional PSD position sensor is used as a mirror method The feedback device to the position realizes a fully closed loop, which can achieve high precision. The two-degree-of-freedom high-speed parallel scanning platform provided by the invention has the characteristics of high precision, high rigidity and strong bearing capacity.

Description

Two-degree-of-freedom high-speed parallel scanning platform and its calibration method for verticality error

technical field

The invention relates to the field of precision optical scanning instruments, in particular to a two-degree-of-freedom high-speed parallel scanning platform and a method for calibrating its verticality error.

Background technique

The optical scanning mechanism is a servo actuator in the field of advanced laser processing and one of the key components of laser projection.

In recent years, parallel mechanisms with few degrees of freedom, especially three-degree-of-freedom parallel mechanisms, such as 3RPS parallel mechanisms, have received more and more attention and favor from researchers in the field of optical scanning. The existing optical scanning angle adjustment platform based on parallel mechanism simultaneously drives three motion branch chains connected between the moving platform and the base through three drivers, so as to realize the movement of the moving platform in three rotational degrees of freedom, or two rotational degrees of freedom and one additional translational degree of freedom for motion.

However, under normal circumstances, the optical scanning mechanism only needs two rotational degrees of freedom, and the extra degrees of freedom will increase the difficulty of kinematic analysis, making the system structure and control more complex. Secondly, if the structure of the kinematic branch chain is too complex, processing and assembly may lead to large system errors. At present, most optical scanning mechanisms adopt the series structure form (gimbal form), this technology is very mature, but due to its own structural characteristics (all the mass of the pitch axis is completely placed on the azimuth axis, the dynamic mass is relatively large ), unable to achieve high-speed scanning motion. There is also a platform system composed of two sets of single axes, which is mainly used in laser projection or incremental manufacturing technology (such as 3D printers), because its dynamic mass is almost only the reflector, and the inertia is very small, so the dynamic performance is very good. High bandwidth, but due to the use of double-mirror reflection, it will bring a certain amount of error accumulation and adverse effects of amplification, and the carrying capacity is very low. For the parallel mechanism with two rotational degrees of freedom, it is mostly used in the fast mirror structure, which can have a high scanning speed but a small scanning range. There are two main mechanical structures of fast mirrors, one is the X-Y axis frame type, also known as the shaft type structure, the inner and outer frames of which rotate around two mutually orthogonal axes to realize the two-dimensional deflection of the plane mirror; The other is a flexible shaftless structure, which mainly utilizes the flexibility of elastic elements to work. The advantages of the first structure are good structural rigidity, strong bearing capacity, and a wide range of rotation angles; its disadvantages are that it requires high precision for the shaft system, and the moment of inertia and frictional moment of the system are too large, which is not conducive to the improvement of the resonance frequency. The volume of this structure is relatively large and is severely limited by space. The second structural advantage is: simple structure, no frictional resistance torque, and fast response speed; but its disadvantage is that the requirements for elastic elements are high, that is, the elastic elements are required to have sufficient flexibility in the desired direction of movement, while in restricting movement It has sufficient rigidity in the direction, which makes the movement form of the plane mirror more complicated when the system is working (it will produce a small amount of linear displacement while generating the angular movement), and is not suitable for use under harsh working conditions such as vibration, impact, and rotation. . In addition, in order to make the structural design symmetrical, the above two structures both use four groups of motors distributed in pairs orthogonally, that is, four inputs are used to control two outputs, which makes the control more complicated and the cost is higher.

Contents of the invention

In view of this, it is necessary to provide a two-degree-of-freedom high-speed parallel scanning optical scanning platform with high-speed and high-precision characteristics for the defects in the existing technology, and to design a verticality error calibration method for the special structure of the scanning platform ;Compared with the fast mirror, while realizing a large deflection angle of the mirror, the complexity of the control mechanism of the scanning platform is reduced, and the original response speed and precision are maintained.

To achieve the above object, the present invention adopts the following technical solutions:

A two-degree-of-freedom high-speed parallel scanning platform, including a casing and a linear drive mechanism installed in the casing, a mirror shaft mechanism, a joint bearing and a PSD position sensor;

The mirror shaft mechanism includes a main shaft, a mirror, a mirror bracket, a leveling screw and a laser emitter. The main shaft is a stepped shaft with a larger diameter at one end and a smaller diameter at the other end. hole, the reflector is fixed on the reflector bracket, and the reflector bracket is fixed on the end face of the main shaft end through a plurality of leveling screws, and the laser emitter is fixed in the through hole at the axis of the main shaft, and its laser emission direction Through the through hole along the axis of the main shaft, pointing to the small shaft end of the main shaft;

The large shaft end of the main shaft is fixed on the inner ring of the joint bearing, and the outer ring of the joint bearing is fixed on the casing;

The PSD position sensor is fixed on the bottom of the casing and is arranged opposite to the small shaft end of the main shaft;

Two linear drive mechanisms are movably installed in the casing, respectively the first linear drive mechanism and the second linear drive mechanism, the motion output ends of the first linear drive mechanism and the second linear drive mechanism are respectively connected to the main shaft, The drive spindle oscillates on the joint bearing around the center of rotation of the joint bearing.

The linear drive mechanism includes a voice coil motor, a movable frame and a guide rail; the movable frame is rotatably connected to the casing, the guide rail is rotatably connected to the movable frame, and the voice coil motor is fixed in the guide rail.

The linear drive mechanism also includes a grating sensor and a photoelectric limit switch fixed in the guide rail, and the grating sensor and the photoelectric limit switch are arranged opposite to the motion output end of the voice coil motor.

The motion output end of the voice coil motor is connected to the main shaft through a ball joint.

A rubber gasket is arranged between the reflector bracket and the main shaft.

The mirror surface of the reflector is perpendicular to the axis of the main shaft.

The rotation center of the joint bearing is located on the mirror surface of the reflector.

The reflector bracket is fixed on the end surface of the major axis end of the main shaft by four leveling screws, and the four screws are evenly distributed on the edge of the reflector bracket.

A connecting portion protrudes from the main shaft, and the connecting portion is elastically connected to the casing or the outer ring of the joint bearing through an elastic connecting piece.

The elastic connector is an elastic rope or a soft spring with an elastic coefficient greater than 300N/m and less than 500N/m.

A method for calibrating the verticality error of the two-degree-of-freedom high-speed parallel scanning platform as described above, comprising the following steps:

S1. Set the projection surface, adjustment bracket and adjustment platform in sequence along a straight line, fix the main shaft on the adjustment bracket, fix the laser emitter on the adjustment platform, and make the laser beam emitted by the laser emitter shoot to the end face of the main shaft end ;

S2. Adjust the axial direction of the spindle and the position of the laser emitter by adjusting the bracket and the platform, so that the laser beam emitted by the laser emitter passes through the through hole of the spindle axis and is projected onto the projection surface;

S3. Install the reflector and the reflector bracket on the main shaft through multiple leveling screws, and fine-tune the mirror direction of the reflector by tightening or loosening the leveling screws, so that the laser beam emitted by the laser transmitter follows the original path return.

The S2 also includes fine-tuning the axial direction of the main shaft by adjusting the bracket, so as to maximize the projection brightness of the laser beam on the projection surface.

A two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention adopts a single-mirror structure, and only one reflection is needed to complete the scanning work, avoiding the error amplification effect caused by double-mirror reflection. At the same time, the present invention adopts a two-input and two-output structure, which is much easier to control than the prior art; it also adopts a joint bearing structure, which can have greater rigidity and deflection angle; and because a two-dimensional PSD position sensor is used as a mirror method The feedback device to the position realizes a fully closed loop, which can achieve high precision. The two-degree-of-freedom high-speed parallel scanning platform provided by the invention has the characteristics of high precision, high rigidity and strong bearing capacity.

Description of drawings

FIG. 1 is a schematic structural diagram of a two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention.

FIG. 2 is a schematic diagram of the internal structure of a two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a mirror axis mechanism in a two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention.

FIG. 4 is a cross-sectional view of the mirror axis mechanism shown in FIG. 3 .

FIG. 5 is a schematic structural diagram of a linear drive mechanism in a two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention.

FIG. 6 is a schematic diagram of a side structure of a two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention.

FIG. 7 is a schematic diagram of another connection mode of the two-degree-of-freedom high-speed parallel scanning platform provided by the embodiment of the present invention.

FIG. 8 is a schematic diagram of the internal bottom surface structure of the two-degree-of-freedom high-speed parallel scanning platform provided by the embodiment of the present invention.

FIG. 9 is a verticality error calibration method for a two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention.

Detailed ways

The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the specification of the present invention.

For reasons of convenience only, in the following description, specific directional terms, such as "up", "down", "left", "right", etc., are used with reference to the corresponding drawings and It should not be regarded as a limitation on the present invention, and when the defined direction of the drawings changes, the directions indicated by these words should be interpreted as correspondingly different directions.

As shown in Figures 1 and 2, a two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention includes a casing 1, a linear drive mechanism installed in the casing 1, a mirror shaft mechanism 3, a joint bearing 4 and PSD position sensor5.

Specifically, as shown in FIGS. 3 and 4 , the mirror shaft mechanism 3 includes a main shaft 31 , a mirror 33 , a mirror bracket 32 , a leveling screw 35 and a laser emitter 34 . The main shaft 31 is a stepped shaft with a larger diameter at one end and a smaller diameter at the other end. There is an axial through hole 310 at the center of the shaft. The mirror 33 is fixed on the mirror bracket 32. The edge of the mirror bracket 32 has Four fixing claws 320 are evenly distributed along the circumference, and the reflector bracket 32 is fixed to the end surface of the major axis end of the main shaft 31 through four leveling screws 35 on the fixing claws 320 . The laser emitter 34 is fixed in the through hole 310 at the axis of the main shaft 31, and is sealed inside the main shaft 31 by the reflector bracket 32. The laser emission direction passes through the through hole 310 along the axis of the main shaft 31 and points to the main shaft 31. small shaft end.

As an improvement, a rubber gasket 36 is also provided between the mirror bracket 32 and the main shaft 31 to provide elastic support for the mirror bracket 32. By adjusting the tightness of the four leveling screws 35 respectively, the mirror bracket 32 can be adjusted. The mirror orientation of the upper mirror 33 is finely tuned and calibrated so that it is perpendicular to the axis of the main shaft 31 to meet the requirements of the two-degree-of-freedom high-speed parallel scanning platform of the embodiment of the present invention.

As shown in Figure 1, the joint bearing 4 includes an inner ring 42 and an outer ring 41, and the outer ring 41 is fixed on the upper cover of the casing 1 (the upper cover in Figure 1 has been removed for easy understanding of the internal structure ), the large shaft end of the main shaft 31 is fixed on the inner ring 42 of the joint bearing 4 .

As shown in Figure 2, the PSD position sensor 5 is fixed on the casing 1 through a flange base 51, arranged under the joint bearing 4, opposite to the small shaft end of the main shaft 31, and used to receive the laser transmitter 34 from the small shaft end. The laser beam signal emitted from the through hole 310 at the shaft end.

There are two linear drive mechanisms, namely a first linear drive mechanism 21 and a second linear drive mechanism 22, and the first linear drive mechanism 21 and the second linear drive mechanism 22 move through a pivot assembly 20 respectively. Installed in the casing 1, they can respectively rotate around a vertical axis.

Specifically, as shown in Figure 5, each linear drive mechanism includes a voice coil motor 23, a movable frame 24, a guide rail 25, a grating ruler sensor 26 and a photoelectric limit switch 27, and the movable frame 24 is rotatably connected to the The casing 1 can rotate around a vertical axis. The guide rail 25 is pivotally connected to the movable frame 24 and can rotate around a horizontal axis. The voice coil motor 23, the grating ruler sensor 26 and the photoelectric limit switch 27 are fixed on the guide rail 25, wherein the voice coil motor 23 is arranged along the extending direction of the guide rail 25 and is fixed on the bottom of the guide rail 25; the grating ruler sensor 26 and the photoelectric limit switch The switch 27 is fixed on the side wall of the guide rail 25 and is arranged opposite to the motion output end of the voice coil motor 23 (ie, the mover 230 ). Among them, the grating ruler sensor 26 is used to feed back the displacement and speed information of the output end of the voice coil motor 23, which is convenient for the control system to control the elongation of the output end of the voice coil motor 23; the photoelectric limit switch 27 is used to limit the position of the voice coil The maximum and minimum motion strokes of the motor 23.

The motion output end of the voice coil motor 23 is the motion output end of the linear drive mechanism. The motion output ends of the first linear drive mechanism 21 and the second linear drive mechanism 22 are respectively connected to the small shaft end of the main shaft 31 from two directions perpendicular to each other on the horizontal plane, and the drive main shaft 31 is wound around the joint bearing 4 on the joint bearing 4 The center of rotation swings. Specifically, the motion output ends of the first linear drive mechanism 21 and the second linear drive mechanism 22 are movably connected to the small shaft end of the main shaft 31 through a ball joint. In practical applications, the motion output ends of the first linear drive mechanism 21 and the second linear drive mechanism 22 can be respectively connected to the main shaft 31 one by one through a ball joint, as shown in FIG. 6 ; It is also possible to connect the motion output ends of the first linear drive mechanism 21 and the second linear drive mechanism 22 to the same plane on the main shaft 31 , as shown in FIG. 7 .

During the swinging process of the drive spindle 31, the motion output ends of the two linear drive mechanisms are mutually restricted. When the motion output end of one of the linear drive mechanisms elongates or contracts, due to the motion output The restriction of end elongation can produce the kinetic energy of lateral swing, which makes itself swing around the vertical axis of movable frame 24, and also makes another linear drive mechanism swing simultaneously. Therefore, during the swinging process of the main shaft 31 , both the first linear drive mechanism 21 and the second linear drive mechanism 22 will swing on the horizontal plane, and the motion output ends of the two linear drive mechanisms are not kept vertical. However, due to the limitation of the joint bearing 4 , the main shaft 31 can only perform three-dimensional rotational swing around the rotation center of the joint bearing 4 .

Since the joint bearing 4 is used as the rotation supporting part of the main shaft 31 , the main shaft 31 also has a degree of freedom along the rotation direction of the joint bearing 4 . And because the power line of the laser transmitter 34 needs to be connected from the outside of the main shaft 31, in the process of swinging the main shaft 31 driven by the two linear drive mechanisms, this degree of freedom of the main shaft 31 in the direction of rotation will affect the layout of the power line; therefore , it is necessary to restrict the degree of freedom of the rotation direction of the main shaft 31 on the joint bearing 4 . As shown in FIG. 6 and FIG. 8 , in the embodiment of the present invention, an elastic connecting member 8 is used to limit the rotational freedom of the main shaft 31 . Specifically, the main shaft 31 has a protruding cylindrical connecting portion 310, and the outer ring 41 of the joint bearing 4 (or the upper cover plate of the casing 1) is also protrudingly provided with a fixing column 40. One end of the connector 8 is fixedly connected to the columnar connecting portion 310, and the other end is fixedly connected to the fixed column 40, so that the main shaft 31 establishes an axial elastic connection with the outer ring 41 of the joint bearing 4, so as to limit the rotation of the main shaft 31 in the direction of rotation. degrees of freedom. Further, in order to meet the requirements of use, an elastic connector 8 with an appropriate elastic coefficient should be selected; in the embodiment of the present invention, the elastic connector 8 is an elastic rope or soft spring with an elastic coefficient greater than 300N/m but less than 500N/m.

In particular, in the embodiment of the present invention, the rotation center of the joint bearing 4 is located on the mirror surface of the mirror 33 , that is, the rotation center of the mirror shaft mechanism 3 is located on the mirror surface. Therefore, no matter where the mirror axis mechanism 3 swings to, the spatial position of the rotation center on the mirror surface of the mirror 33 remains constant.

During the movement, each set of elongation data of the first linear drive mechanism 21 and the second linear drive mechanism 22 corresponds to a three-dimensional swing position of the shaft center of the main shaft 31, that is, corresponds to a normal direction of the mirror 33 Correspondingly, the angle also corresponds to the position of the laser beam emitted by the laser emitter 34 on the PSD position sensor 5 . Therefore, the PSD position sensor 5 located below the mirror shaft mechanism 3 can directly feed back the three-dimensional normal direction of the mirror 33 .

The two-degree-of-freedom high-speed parallel scanning platform provided by the embodiment of the present invention is a two-input and two-output system, which controls the normal direction of the mirror 33 by separately controlling the elongation of the two linear voice coil motors 23 . Since the voice coil motor 23 has a high acceleration, the scanning speed of the mirror 33 can be very fast. In some scanning platform systems in the prior art, since the motion of the two motors is not linearly corresponding to the normal motion of the mirror, there is coupling between the two; and because the mirror does not have a fixed center of rotation, the rotation The center cannot coincide with the reflection point, which makes it difficult to solve the equation of motion of the two motors given the equation of motion of the reflected light.

However, in the embodiment of the present invention, the center of rotation of the mirror shaft mechanism 3 is fixed and located on the mirror surface of the mirror 33, that is, the reflection point coincides with the center of rotation, and the related mathematical model is much simpler. In the motion control method, the information of the PSD position sensor 5 is discretized, so that each discrete point on the PSD position sensor 5 corresponds to the unique elongation of the two voice coil motors 23, and a data table is established. In actual control, by discretizing the equation of motion of the given reflected light to find the elongation length of each group of the corresponding two voice coil motors 23, the corresponding discrete points can be fitted to the equation of motion corresponding to the reflected light The equations of motion of the two voice coil motors 23. In the two-degree-of-freedom high-speed parallel scanning platform provided by the embodiment of the present invention, the scanning accuracy mainly depends on the accuracy of the PSD position sensor 5 and the grating ruler sensor 26, the perpendicularity between the reflective surface of the mirror 33 and the through hole 310 of the main shaft 31. degree, and the distance error between the reflective surface of the mirror 33 and the center of rotation of the mirror (that is, the center of rotation of the joint bearing 4).

Since the accuracy of the PSD position sensor 5 and the grating ruler sensor 26 can be improved by selecting different product models, the distance error between the reflective surface of the mirror 33 and the center of rotation can be overcome by improving the installation process, so no more details here . In the prior art, the error of the PSD position sensor 5 can reach several micrometers, and the accuracy of the grating ruler sensor 26 can reach the highest nanometer level.

As shown in Figure 8, the present invention also provides a method for calibrating the verticality error of the two-degree-of-freedom high-speed parallel scanning platform, specifically, the verticality refers to the reflection surface of the mirror 33 and the main axis The verticality of the through hole 310 of 31.

Described perpendicularity error calibration method specifically comprises the following steps:

S1, set the projection surface 61, the adjustment bracket 62 and the adjustment platform 63 sequentially along a straight line, fix the main shaft 31 on the adjustment bracket 62, fix a laser emitter 7 on the adjustment platform 63, and make the laser emitter 7 emit The laser beam shoots to the end face of the main axis end of the main shaft 31; wherein, the adjustment bracket 62 has two degrees of freedom of adjustment in the rotation direction, which are respectively used to adjust the horizontal and vertical directions of the axis center of the main shaft 31; the adjustment platform 63 has three The degrees of freedom for adjusting the translation direction are respectively used to adjust the displacement of the laser emitter 7 in the X-axis, Y-axis and Z-axis directions.

S2. Adjust the axial direction of the main shaft 31 and the position of the laser emitter 7 respectively by adjusting the bracket 62 and the adjustment platform 63, so that the laser beam emitted by the laser emitter 7 passes through the through hole 310 of the shaft center of the main shaft 31 and is projected onto the On the projection surface 61; the positions of the main shaft 31 and the laser emitter 7 are preliminarily fixed; further, the axial direction of the main shaft 31 is fine-tuned by adjusting the bracket 62, so that the brightness of the projection point P of the laser beam on the projection surface 61 reaches the maximum , which indicates that the direction of the laser beam coincides with the direction of the through hole 310 of the axis of the main shaft 31 at the highest degree of coincidence; after the adjustment, the main shaft 31 is locked and fixed on the adjustment bracket 62 .

S3, reflector 33 and reflector support 32 are installed on the main shaft 31 through described four leveling screws 35, and the laser beam can be reflected by reflector 33 at this moment; By tightening or loosening leveling screw 35, reflector The direction of the mirror surface of 33 is fine-tuned, so that the laser beam emitted by the laser transmitter 7 returns along the original path.

Correction by the above method can make the mirror surface of the reflector 33 and the through hole 310 of the main shaft 31 have a high degree of perpendicularity. Wherein, during the correction process, the greater the distance L between the mirror surface of the reflector 33 and the laser reflector 7, the higher the adjustment accuracy and the higher the finally corrected perpendicularity.

A two-degree-of-freedom high-speed parallel scanning platform provided by an embodiment of the present invention adopts a single-mirror structure, and only one reflection is needed to complete the scanning work, avoiding the error amplification effect caused by double-mirror reflection. At the same time, the present invention adopts a two-input and two-output structure, which is much easier to control than the prior art; it also adopts a joint bearing structure, which can have greater rigidity and deflection angle; and because a two-dimensional PSD position sensor is used as a mirror method The feedback device to the position realizes a fully closed loop, which can achieve high precision. The two-degree-of-freedom high-speed parallel scanning platform provided by the invention has the characteristics of high precision, high rigidity and strong bearing capacity.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. a two-freedom high speed parallel scan platform, is characterized in that, comprises casing and the straight line driving mechanism be installed in casing, mirror axis mechanism, oscillating bearing and PSD position transducer;

Described mirror axis mechanism comprises main shaft, catoptron, mirror support, levelling bolt and generating laser, described main shaft is the multidiameter that one end diameter larger one end diameter is less, its axle center place has the through hole of an axis, described catoptron is fixed on mirror support, mirror support is fixed on the end face of the large axle head of main shaft by multiple levelling bolt, described generating laser is fixed in the through hole at spindle axis place, through hole is passed along the axle center of main shaft in its Laser emission direction, points to the little axle head of main shaft;

The minute surface of described catoptron is perpendicular to the axle center of main shaft; The rotation center of described oscillating bearing is positioned on the minute surface of catoptron;

The large axle head of described main shaft is fixed on the inner ring of oscillating bearing, and the outer ring of oscillating bearing is fixed on casing;

Described PSD position transducer is fixed on casing, is oppositely arranged with the little axle head of main shaft;

Two straight line driving mechanisms are movably installed in casing, be respectively the first straight line driving mechanism and the second straight line driving mechanism, described first straight line driving mechanism is connected with main shaft respectively with the movement output end of the second straight line driving mechanism, and drive shaft swings around the rotation center of oscillating bearing on oscillating bearing.

2. two-freedom high speed parallel scan platform according to claim 1, it is characterized in that, described straight line driving mechanism comprises voice coil motor, movable frame and guide rail; Described movable frame is rotatably connected on casing, and described guide rail is rotatably connected on movable frame, and described voice coil motor is fixed in guide rail.

3. two-freedom high speed parallel scan platform according to claim 2, it is characterized in that, described straight line driving mechanism also comprises the grating scale sensor, the photoelectric limit switch that are fixed in guide rail, and the movement output end of described grating scale sensor and photoelectric limit switch and voice coil motor is oppositely arranged.

4. two-freedom high speed parallel scan platform according to claim 2, it is characterized in that, the movement output end of described voice coil motor is connected by ball pivot with main shaft.

5. two-freedom high speed parallel scan platform according to claim 1, is characterized in that, be provided with rubber sheet gasket between described mirror support and main shaft.

6. two-freedom high speed parallel scan platform according to claim 1, it is characterized in that, described mirror support is fixed on the end face of the large axle head of main shaft by four levelling bolts, and described four screws are uniformly distributed in the edge of mirror support.

7. two-freedom high speed parallel scan platform according to claim 1, is characterized in that, described main shaft is convexly equipped with a junction, and described connecting portion is connected with the outer ring elasticity of casing or oscillating bearing by a Flexible Connector.

8. two-freedom high speed parallel scan platform according to claim 7, is characterized in that, described Flexible Connector is elastic threads or the soft spring that elasticity coefficient is greater than 300N/m and is less than 500N/m.

9. a calibration steps for the error of perpendicularity of two-freedom high speed parallel scan platform as claimed in claim 1, is characterized in that, comprise the following steps:

S1, set gradually projecting plane, adjusting pole and adjustment platform along a straight line, main shaft is fixed on adjusting pole, generating laser is fixed on adjustment platform, the end face of the large axle head of laser beam directive main shaft that laser transmitter projects is gone out;

S2, by adjusting pole and adjustment platform, the adjustment axial direction of main shaft and the position of generating laser, the laser beam that laser transmitter projects is gone out, through the through hole of spindle axis, projects on projecting plane;

S3, be arranged on main shaft by catoptron and mirror support by multiple levelling bolt, by screwing or loosening levelling bolt, finely tune the minute surface direction of catoptron, the laser beam that laser transmitter projects is gone out returns along former road.

10. method according to claim 9, is characterized in that, described S2 is also comprised and being finely tuned by the axial direction of adjusting pole to main shaft, makes laser beam projection brightness on the projection surface reach maximum.