Precise six-foot displacement table

Abstract

A precise six-foot displacement table provided by the present invention comprises a top plate, driving legs and a base, each driving leg comprises an outer shell, an inner shell, a motor stator and a motor rotor, the outer shell sleeves the inner shell and is slidably connected with the inner shell, a support is installed at the top of the inner side of the inner shell, the motor stator is installed at the bottom of the inner side of the inner shell, and the motor rotor is installed in the motor stator. A lead screw is installed in the motor rotor, a bearing is installed in the support, a ball nut is installed above the bearing and connected with an inner ring of the bearing, a coded disc is installed below the bearing and connected with the inner ring of the bearing, an installation groove is formed in the same horizontal position of the inner shell and the coded disc, and a grating ruler reading head is installed on the installation groove. Through the design of an incremental rotating grating system, a measuring point and a load moving point are on the same axis, and Abbe errors caused by deviation of a measuring axis and a moving axis are reduced to the maximum extent; through the design of an incremental rotating grating system, closed-loop control is achieved, the positioning precision can reach the nanoscale, and the minimum positioning precision is 20 nm.

Description

Technical Field

[0001] This invention relates to the field of displacement control technology, specifically a precision six-legged displacement stage. Background Technology

[0002] Traditional six-legged displacement stages rely on a long transmission chain of "motor-coupling-rotating screw" for displacement drive. The coupling introduces backlash and elastic deformation, resulting in sluggish dynamic response. Indirect measurement at the motor end cannot sense the actual displacement at the end, making it impossible to correct Abbe error and transmission error through closed-loop control. These limitations make it difficult for the system accuracy to break through the micrometer level. Summary of the Invention

[0003] The purpose of this invention is to provide a precision six-legged displacement stage to solve the problems existing in the background art.

[0004] The technical solution of this invention is implemented as follows: A precision six-legged displacement stage includes a top plate, driving legs, and a base. There are six driving legs, arranged in pairs, with each pair arranged in a figure-eight pattern. The top of each driving leg is connected to the bottom of the top plate via an upper Hooke's hinge, and the bottom of each driving leg is connected to the top of the base via a lower Hooke's hinge. Each driving leg includes an outer shell, an inner shell, a motor stator, and a motor rotor. The outer shell is slidably fitted over the inner shell. A bracket is installed on the top inner side of the inner shell, and the motor stator is installed on the bottom inner side of the inner shell. The motor rotor is installed inside the motor stator, and a lead screw is installed inside the motor rotor. A bearing is installed inside the bracket. A ball nut is installed above the bearing and connected to the inner ring of the bearing. A code disk is installed below the bearing and connected to the inner ring of the bearing. The lead screw passes through the code disk, the bearing, and the ball nut, and is in rolling connection with it. The inner shell and the code disk are opened at the same horizontal position. The device has an installation slot on which a grating ruler reading head is installed. An opening is formed at the same horizontal position as the bracket, the encoder, and the grating ruler reading head. A slider is installed at the bottom of the lead screw, and a connecting rod is installed at the top of the lead screw. A fixing plate is installed at the bottom of the upper Hooke hinge. The connecting rod passes through the fixing plate and is vertically connected to the upper Hooke hinge by screws. A limit plate is installed at the top of the motor rotor. A positioning sleeve is installed at the bottom of the encoder and is fixedly connected to the limit plate. An internal thread is provided on the inner side of the top of the outer shell, and an external thread is provided on the outer side of the bottom of the inner shell. An internal thread is provided on the inner side of the upper part of the lower Hooke hinge, and an external thread is provided on the lower part of the upper Hooke hinge. The outer shell is connected to the upper Hooke hinge via the internal thread and locked in place by a lock nut. The inner shell is connected to the lower Hooke hinge via the external thread. The motor stator and the grating ruler reading head are connected to a controller via cables.

[0005] Furthermore, both the top plate and the base are made of stainless steel plates in a circular structure.

[0006] Furthermore, the top plate is provided with fixing holes.

[0007] Furthermore, the base is provided with mounting holes.

[0008] Furthermore, the outer shell, inner shell, and support are all made of stainless steel in a cylindrical structure.

[0009] Furthermore, the code disk is engraved with uniform bright and dark scale lines and a zero-position scale line. The code disk and the grating ruler reading head form an incremental rotating grating system. When the code disk rotates, the bright and dark scale lines on the code disk pass through the grating ruler reading head, generating periodic changes in light intensity. The system can measure the angular displacement of the ball nut rotation with extreme precision.

[0010] The beneficial effects of this invention are as follows: This invention utilizes an incremental rotating grating system design to ensure that the measurement point and the load movement point are on the same axis, minimizing Abbe errors caused by misalignment between the measurement and movement axes. The motor rotor is connected to the encoder disk, driving the rolling nut to rotate synchronously without a coupling. This highly integrated, direct drive method without mechanical transmission links reduces connection gaps, improves positioning accuracy, and provides a higher natural frequency and faster acceleration / deceleration capabilities for rapid response. The incremental rotating grating system design allows for real-time measurement and feedback of the encoder disk's rotation angle. The controller compares the target angle with the measured angle and immediately drives the rolling nut to rotate again for error compensation until the measured value perfectly matches the target value, achieving closed-loop control. Positioning accuracy can reach the nanometer level, with a minimum positioning accuracy of 20 nm.

[0011] The displacement stage of this invention consists of six variable-length drive legs, each of which is connected to the top plate and the base via a Hooke hinge, enabling six degrees of freedom of movement. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the present invention.

[0013] Figure 2 This is a schematic diagram of the drive leg of the present invention.

[0014] In the diagram: 1-Top plate, 2-Drive leg, 201-Outer shell, 202-Inner shell, 203-Bracket, 204-Motor stator, 205-Motor rotor, 206-Lead screw, 207-Bearing, 208-Ball nut, 209-Code disc, 210-Mounting slot, 211-Raster ruler reading head, 212-Opening, 213-Slider, 214-Connecting rod, 215-Screw, 216-Fixing plate, 217-Limiting plate, 218-Positioning sleeve, 219-Internal thread one, 220-External thread one, 217-3-Base, 4-Upper Hooke hinge, 401-External thread two, 402-Locking nut, 5-Lower Hooke hinge, 501-Internal thread two, 6-Fixing hole, 7-Mounting hole. Detailed Implementation

[0015] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] like Figure 1-2As shown, a precision six-legged displacement stage includes a top plate 1, drive legs 2, and a base 3. There are six drive legs 2, arranged in pairs in a V-shape. The top ends of the drive legs 2 are connected to the bottom of the top plate 1 via upper Hooke hinges 4, and the bottom ends of the drive legs 2 are connected to the top of the base 3 via lower Hooke hinges 5. Each drive leg 2 includes an outer shell 201, an inner shell 202, a motor stator 204, and a motor rotor 205. The outer shell 201 is slidably fitted onto the outer shell 202. A bracket 203 is installed on the top inner side of the inner shell 202, and a bracket 203 is installed on the bottom inner side of the inner shell 202. The system includes a motor stator 204, inside which a motor rotor 205 is installed. A lead screw 206 is installed inside the motor rotor 205. A bearing 207 is installed inside a bracket 203. A ball nut 208 is installed above the bearing 207 and connected to its inner ring. A code disk 209 is installed below the bearing 207 and connected to its inner ring. The lead screw 206 passes through the code disk 209, the bearing 207, and the ball nut 208, and is in rolling contact with them. An installation groove 210 is provided on the inner shell 202 at the same horizontal position as the code disk 209. A grating ruler reading head 211 is installed on the 0. An opening 212 is formed at the same horizontal position as the code disk 209 and the grating ruler reading head 211 on the bracket 203. A slider 213 is installed at the bottom of the lead screw 206, and a connecting rod 214 is installed at the top of the lead screw 206. A fixing plate 216 is installed at the bottom of the upper Hooke hinge 4. The connecting rod 214 passes through the fixing plate 216 and is vertically connected to the upper Hooke hinge 4 by screws 215. A limit plate 217 is installed at the top of the motor rotor 205, and a positioning sleeve 218 is installed at the bottom of the code disk 209. The positioning sleeve 218 and the limit plate 217 are connected. 7. Connection and fixation: The inner side of the top of the outer shell 201 is provided with an internal thread 219, the outer side of the bottom of the inner shell 202 is provided with an external thread 220, the inner side of the upper part of the lower Hooke hinge 5 is provided with an internal thread 501, the lower part of the upper Hooke hinge 4 is provided with an external thread 401, the outer shell 201 is connected to the external thread 401 of the upper Hooke hinge 4 through the internal thread 219, and is locked and fixed by a locking nut 402, the inner shell 202 is connected to the internal thread 501 of the lower Hooke hinge 5 through the external thread 220, and the motor stator 205 and the grating ruler reading head 211 are connected to the controller 8 through a cable.

[0017] Both the top plate 1 and the base 3 are made of stainless steel plates in a circular structure.

[0018] The top plate 1 is provided with fixing holes 6.

[0019] The base 2 is provided with mounting holes 7.

[0020] The outer shell 201, inner shell 202, and support 203 are all made of stainless steel in a cylindrical structure.

[0021] The code disk 209 is engraved with uniform light and dark scale lines and a zero-position scale line. The code disk 209 and the grating ruler reading head 211 form an incremental rotating grating system. When the code disk 209 rotates, the light and dark scale lines on the code disk 209 pass through the grating ruler reading head 211, producing periodic changes in light intensity. The system can measure the angular displacement of the ball nut 209 rotation with extremely high precision.

[0022] During installation or calibration, the controller 8 controls the movement of the drive leg 2 so that the grating ruler reading head 211 passes through the zero-position mark on the code disk 209. At this time, the controller 8 records this physical position as the system zero position. Under continuous power supply, the controller 8 will continuously count the incremental pulses to confirm the accurate angle of the ball nut 208 relative to the zero position at any time.

[0023] During operation, after receiving the movement command of the top plate 1, the controller 8 controls the rotating magnetic field of the motor stator 204 of the drive leg 2, thereby controlling the rotation of the motor rotor 205, which in turn drives the encoder 209 and the ball nut 208 to rotate synchronously, thereby driving the lead screw 206 to move up and down, thereby driving the outer shell 202 and the upper Hooke hinge 4 to move, thus realizing the movement of the top plate 1. When the encoder 208 rotates, the grating ruler reading head 211 measures and provides feedback on the rotation angle of the encoder 208 in real time. By comparing the difference between the target angle and the measured angle, the controller 8 will immediately adjust the current of the motor stator 204, drive the ball nut 208 to rotate again for error compensation, until the measured value is completely consistent with the target value, thus realizing closed-loop control.

[0024] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A precision six-legged displacement stage, comprising a top plate, drive legs, and a base, characterized in that, The drive legs consist of six legs, arranged in pairs, with each pair forming a V-shape. The top of each drive leg is connected to the bottom of the top plate via an upper Hooke's hinge, and the bottom of each drive leg is connected to the top of the base via a lower Hooke's hinge. Each drive leg includes an outer shell, an inner shell, a motor stator, and a motor rotor. The outer shell is slidably fitted over the inner shell. A bracket is mounted on the top inner side of the inner shell, and the motor stator is mounted on the bottom inner side of the inner shell. The motor rotor is installed inside the motor stator, and a lead screw is installed inside the motor rotor. A bearing is installed inside the bracket, and a ball nut is installed above the bearing and connected to its inner ring. A code disk is installed below the bearing and connected to its inner ring. The lead screw passes through the code disk, the bearing, and the ball nut, and is in rolling connection with it. An installation groove is formed at the same horizontal position as the code disk on the inner shell, and a grating ruler is installed in the installation groove. The device includes a reading head, a bracket with an opening at the same horizontal position as the encoder and the grating ruler reading head, a slider installed at the bottom of the lead screw, a connecting rod installed at the top of the lead screw, a fixing plate installed at the bottom of the upper Hooke hinge, the connecting rod passing through the fixing plate and vertically connected to the upper Hooke hinge by screws, a limit plate installed at the top of the motor rotor, a positioning sleeve installed at the bottom of the encoder, the positioning sleeve being connected and fixed to the limit plate, an internal thread on the inner side of the top of the outer shell, an external thread on the outer side of the bottom of the inner shell, an internal thread on the inner side of the upper part of the lower Hooke hinge, and an external thread on the lower part of the upper Hooke hinge, the outer shell being connected to the external thread of the upper Hooke hinge via the internal thread and locked by a lock nut, the inner shell being connected to the internal thread of the lower Hooke hinge via the external thread, and the motor stator and the grating ruler reading head being connected to a controller via cables.

2. The precision hexapod displacement stage according to claim 1, characterized in that, Both the top plate and the base are made of stainless steel plates in a circular structure.

3. A precision six-legged displacement stage according to claim 1, characterized in that, The top plate is provided with fixing holes.

4. A precision six-legged displacement stage according to claim 1, characterized in that, The base is provided with mounting holes.

5. A precision hexapod displacement stage according to claim 1, characterized in that, The outer shell, inner shell, and support are all made of stainless steel in a cylindrical structure.

6. A precision hexapod displacement stage according to claim 1, characterized in that, The code disk is engraved with uniform light and dark scale lines and a zero-position scale line. The code disk and the grating ruler reading head form an incremental rotating grating system. When the code disk rotates, the light and dark scale lines on the code disk pass through the grating ruler reading head, producing periodic changes in light intensity. The system can measure the angular displacement of the ball nut rotation with extreme precision.

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