A six-degree-of-freedom redundant drive flexible parallel platform based on cubic configuration

Abstract

This invention discloses a spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge, comprising a moving platform, a fixed platform, and multiple drive modules. Each drive module consists of a driver and a two-axis flexible hinge. The driver provides linear displacement, and the elastic deformation of the two-axis flexible hinge achieves complete decoupling from the motion platform. The drive modules are divided into longitudinal drive modules and transverse drive modules. All components are connected by screws. The moving platform is fixedly connected to each drive module by screws. By energizing the drivers in each drive module, the desired motion is achieved and transmitted to the moving platform, realizing the movement of the moving platform in six degrees of freedom. Each drive module in this invention is directly or indirectly fixedly connected to the fixed platform at the bottom, forming a parallel motion platform capable of high-precision movement along the corresponding strokes in the X, Y, and Z directions, as well as precise rotation around the X, Y, and Z axes.

Description

Technical Field

[0001] This invention belongs to the field of precision drive and control technology, and particularly relates to a flexible six-degree-of-freedom redundant drive parallel platform based on a cubic configuration with three translational and three rotational axes. Background Technology

[0002] In recent years, with the development of precision machinery technology, the development of micro- and nano-motion platforms has greatly aided precision manufacturing and metrology. For example, micro- and nano-motion platforms are indispensable instruments in laser welding, photolithography processes for semiconductors and thin-film transistor liquid crystal displays, probe and object positioning in atomic force microscopes and scanning probe microscopes, as well as in cell biology and medical research. This practical need has spurred extensive research into the design of micro- and nano-motion platforms in recent years.

[0003] While traditional mechanical transmission mechanisms are widely used in current precision motion platforms, they often face problems such as friction and backlash, which limit their performance in precision motion. Friction leads to energy loss and instability, while backlash can introduce uncertainties and errors in motion. To address these challenges, more and more research and engineering practices are exploring new solutions, such as flexible hinge drives, piezoelectric stacks, and magnetostrictive material drives.

[0004] As our understanding of parallel mechanisms deepens, classic parallel motion platforms, such as the Stewart mechanism, have received extensive research. This mechanism achieves motion in six degrees of freedom through the coordinated drive of six links. However, due to the structural characteristics of the Stewart mechanism, the coupled motion of each drive shaft is highly complex, making control difficult and posing challenges to precise control. Summary of the Invention

[0005] The purpose of this invention is to provide a six-degree-of-freedom redundant drive flexible parallel platform based on a cubic configuration, which has a small spatial size, strong mechanical decoupling capability, and simple control.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] A spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge includes: a moving platform, a fixed platform, a drive module assembly, and a motion control module; the drive module assembly consists of a linear actuator and a flexible hinge mechanism, and the motion guidance and complete mechanical decoupling are achieved through the elastic deformation of the flexible hinge mechanism; the motion control module is used to drive the platform to achieve six-degree-of-freedom motion.

[0008] In some embodiments of the present invention, the drive modules are configured as eight redundant drive modules, including four drive modules that provide longitudinal displacement and four drive modules that provide lateral displacement. The linear actuators of the longitudinal drive modules and the lateral drive modules are arranged orthogonally in space, together providing drive capability for six degrees of freedom motion.

[0009] In some embodiments of the present invention, the above-mentioned flexible hinge mechanism includes a decoupling flexible hinge and a guiding flexible hinge; the decoupling flexible hinge is a two-axis flexible hinge or a two-axis double-through flexible hinge, the two-axis flexible hinge realizes the connection between a single set of drive modules and the moving platform and the rotational decoupling around two axes, and the two-axis double-through flexible hinge realizes the connection between two sets of drive modules and the moving platform and the bidirectional decoupling; the guiding flexible hinge is a straight beam moving pair flexible hinge or a quasi-elliptical variable cross-section flexible hinge.

[0010] In some embodiments of the present invention, the linear actuator is a piezoelectric drive assembly, a voice coil motor drive assembly, or a linear motor; the linear actuator may integrate a rhombic displacement amplification mechanism or a lever displacement amplification mechanism to adapt to micro-nano to centimeter-level stroke requirements.

[0011] In some embodiments of the present invention, the linear actuator of the above-mentioned drive module assembly is divided into a fixed type and a floating type; one end of the fixed type drive module is connected to the moving platform through a decoupled flexible hinge, and the other end is fixed to the fixed platform, and its position remains unchanged during operation; both ends of the floating type drive module are connected through a decoupled flexible hinge, and it can swing slightly during operation.

[0012] In some embodiments of the present invention, the above-mentioned drive module assembly can be replaced by four sets of two-axis drive module groups. Each set of two-axis drive module groups includes two orthogonally arranged linear actuators, an elliptical guide mechanism, a two-axis flexible hinge and a two-axis double-pass flexible hinge. Each set of two-axis drive module groups can output orthogonal displacement in the horizontal and vertical directions.

[0013] In some embodiments of the present invention, the motion control module can perform inverse kinematics solution on the external control signal to generate control commands for each linear actuator, thereby driving the motion platform to achieve translation along the X, Y, and Z directions and rotation around the X, Y, and Z axes.

[0014] In some embodiments of the present invention, the motion control module integrates a strain sensor, which detects the elongation of the linear actuator and generates a displacement feedback signal to achieve closed-loop control of the platform motion.

[0015] In some embodiments of the present invention, the components of the moving platform, the fixed platform, and the drive module assembly are all fastened together by screws, and the whole assembly adopts a cubic configuration.

[0016] In some embodiments of the present invention, the above-mentioned spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge can realize the rotation of the moving platform around the X-axis or Y-axis by controlling the relative linear actuators to apply equal voltages of "one rising and one falling"; and can realize the rotation of the moving platform around the Z-axis by controlling four sets of linear actuators to "diagonally rise and fall equally".

[0017] Specifically, in some embodiments of the present invention, the drive module consists of a linear driver and a flexible hinge mechanism, relying on the elastic deformation of the flexible hinge mechanism to achieve complete mechanical decoupling of the motion platform.

[0018] Specifically, in some embodiments of the present invention, the drive modules constitute a drive module assembly, which consists of eight single-axis drive modules or four two-axis drive module groups. The drive module assembly consisting of eight single-axis drive modules is divided into four longitudinal drive modules and four transverse drive modules. The drivers in the longitudinal drive modules are placed vertically to provide longitudinal displacement, while the drivers in the four transverse drive modules are placed transversely to provide transverse displacement. In the drive module assembly consisting of four two-axis drive module groups, each two-axis drive module group can generate a pair of orthogonal movements, including a horizontal displacement and a vertical displacement. The moving platform is fixedly connected to each drive module by screws. By energizing the drivers in each drive module, the corresponding displacement is achieved. The drivers are protected by guide flexible hinges, and the displacement is transmitted to the moving platform through two-axis flexible hinges or two-axis double-through flexible hinges, thus realizing the movement of the moving platform. The moving platform, through the cooperation between the various drive modules, achieves high-precision movement along the required stroke in the X, Y, and Z directions, as well as precise rotation around the X, Y, and Z axes.

[0019] Specifically, all components are connected by screws for secure fastening. One end of the drive module is fixedly connected to the moving platform via a two-axis flexible hinge or a two-axis double-through flexible hinge within the drive module, while the other end is fixedly connected to the stationary platform via a driver (or a two-axis flexible hinge at the other end of the drive module). In summary, this achieves the assembly of a novel, fully decoupled parallel precision motion platform with six degrees of freedom.

[0020] Specifically, the drive section is connected to a motion control module, which performs inverse kinematics calculations on the control signals to control the platform's motion via the drive components.

[0021] Specifically, the motion control module includes a strain sensor or other types of sensors. The strain sensor detects the position and attitude of the platform through the signal generated by its deformation, and uses it as a displacement feedback signal for the controller to achieve closed-loop control.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention is a six-degree-of-freedom redundant driven flexible parallel platform based on a cubic configuration. Its key feature is that it can achieve motion in all six degrees of freedom through simple control of the corresponding drive modules. This invention possesses strong mechanical decoupling capabilities and is easy to control; furthermore, it has a small spatial size, and all component units can be manufactured using wire cutting. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional perspective view of the single-axis drive module on the platform of the present invention;

[0026] Figure 2 This is a three-dimensional perspective view of the two-axis drive module assembly on the platform of this invention;

[0027] Figure 3 This is an assembly diagram of the fixed / lateral drive module assembly on the single-axis drive module of the present invention.

[0028] Figure 4 This is a schematic diagram of the assembly of the longitudinal drive module of the single-axis drive module on the platform of the present invention;

[0029] Figure 5 This is the two-axis drive module group in the platform of the present invention;

[0030] Figure 6 It is the dual-axis double-through flexible hinge in the platform of this invention;

[0031] Figure 7 It refers to the piezoelectric ceramic and elliptical guide mechanism in the platform of this invention.

[0032] In the diagram: 1. Cover plate; 2. Upper fixed / lateral drive module assembly; 2-1. Upper fixed outer frame; 2-2. Upper fixed inner frame; 2-3. Guide beam; 2-4. Piezoelectric ceramic; 2-5. Two-axis flexible hinge; 2-6. Pre-tightening device; 3. Column; 4. Fixed platform 1; 5. Moving platform connection; 6. Moving platform 1; 7-1. Two-axis flexible hinge; 7-2. Guide beam; 7-3. Piezoelectric ceramic; 7-4. Pre-tightening device; 7. Longitudinal drive module; 8. Moving platform 2; 9. Two-axis drive module assembly; 9-1. Piezoelectric ceramic; 9-2. Elliptical guide mechanism; 9-3. Two-axis double-pass flexible hinge; 9-4. Two-axis flexible hinge; 10. L-shaped fixed frame; 11. Fixed platform 2. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] Example 1

[0036] like Figure 1 As shown, the present invention relates to a six-degree-of-freedom redundant drive flexible parallel platform based on a cubic configuration (composed of eight single-axis drive modules), the main structure of which includes a cover plate 1, an upper fixed / lateral drive module assembly 2, a column 3, a fixed platform 4, a moving platform connection 5, a moving platform 6, and a longitudinal drive module 7.

[0037] like Figure 1 As shown, the column 3 and the longitudinal drive module 7 are fixedly connected to the lower fixed assembly by screws, and the four longitudinal drive mechanisms are directly connected and fastened to each other by screws. The biaxial flexible hinge 7-1 is located on the longitudinal drive module 7, and together with the guide beam 7-2, the piezoelectric ceramic 7-3, and the pre-tensioning device 7-4, it forms the longitudinal drive module 7. A biaxial flexible hinge 2-5 is also connected to the corresponding position in the upper fixed / lateral drive module assembly 2, and together with the upper fixed outer frame 2-1, the upper fixed inner frame 2-2, the guide beam 2-3, the piezoelectric ceramic 2-4, and the pre-tensioning device 2-6, it forms the upper fixed / lateral drive module assembly 2. For the specific composition of the longitudinal drive module 7 and the upper fixed / lateral drive module assembly 2, please refer to... Figure 3 and Figure 4 The moving platform 6 is fastened to the biaxial flexible hinge 7-1 in the longitudinal drive module 7 by screws, and to the biaxial flexible hinge 2-5 in the upper fixed / lateral drive module assembly 2 by screws, thereby realizing the transmission of motion. The moving platform connecting plate 5 is close to the upper part of the moving platform 6 and is connected to the moving platform 6 by screws to reinforce the moving platform 6. At the same time, the threaded hole on the top can be used to fix the external platform. The cover plate 1 is located above the upper fixed / lateral drive module assembly 2 and is connected to the upper fixed / lateral drive module assembly 2 by screws to further support and fix the upper fixed outer frame 2-1 and the upper fixed inner frame 2-2.

[0038] Furthermore, the six-degree-of-freedom redundant driven flexible parallel platform (single-axis drive module) based on a cubic configuration can achieve complete mechanical decoupling of the six degrees of freedom through two-axis flexible hinges 2-5 and 7-1, and the motion control is simple. After the piezoelectric ceramics 7-3 in the four longitudinal drive modules 7 are energized, the longitudinal displacement of the moving platform 6 can be achieved by controlling the voltage magnitude; after the piezoelectric ceramics 7-3 in any two opposite longitudinal drive modules 7 are energized, by controlling the voltage of one piezoelectric ceramic 7-3 to increase and the voltage of the other piezoelectric ceramic 7-3 to decrease by an equal amount, the flipping motion of the moving platform 6 around the two axes of the plane can be achieved; in the upper fixed / lateral drive module assembly 2, the four piezoelectric ceramics 2-4 are energized simultaneously, and the rotation of the moving platform 6 can be achieved by controlling the voltage magnitude; after the piezoelectric ceramics 2-4 in any two opposite piezoelectric ceramics 2-4 in the upper fixed / lateral drive module assembly 2 are energized, by controlling the voltage of one piezoelectric ceramic 2-4 to increase and the voltage of the other piezoelectric ceramic 2-4 to decrease by an equal amount, the translational motion of the moving platform 6 along the two axes of the plane can be achieved. Ultimately, six degrees of freedom motion is achieved.

[0039] Furthermore, the drive unit is connected to a motion control module, which performs inverse kinematics calculations on the control signals to direct the linear drive assembly to control the platform's movement. The motion control module includes a strain sensor or other type of sensor. The strain sensor detects the elongation of the linear drive through the signal generated by its deformation, which serves as the displacement feedback signal for the controller to achieve closed-loop control.

[0040] Example 2

[0041] like Figure 2 As shown, the present invention relates to a six-degree-of-freedom redundant drive flexible parallel platform based on a cubic configuration (composed of four two-axis drive module groups), the main structure of which includes a moving platform 8, two-axis drive module group 9, L-shaped fixed frame 10, and fixed platform 11.

[0042] like Figure 2 As shown, the piezoelectric ceramic 9-1, the elliptical guide mechanism 9-2, the biaxial double-pass flexible hinge 9-3, and the biaxial flexible hinge 9-4 constitute a two-axis drive module group 9. The biaxial flexible hinges 9-3 at both ends of the two-axis drive module group 9 are fixed to the L-shaped fixed frame 10 by screws, and the rigid part in the middle of the biaxial double-pass flexible hinge 9-4 is fixed to the moving platform 8 by screws. The L-shaped fixed frame is fixedly connected to the fixed platform 11.

[0043] Furthermore, the six-degree-of-freedom redundant driven flexible parallel platform (two-axis drive module group) based on a cubic configuration can achieve complete mechanical decoupling of the six degrees of freedom through the two-axis flexible hinge 9-4 and the two-axis double-through flexible hinge 9-3, and the motion control is simple. In the two-axis drive module group 9, the longitudinally placed piezoelectric ceramics 9-1 are simultaneously supplied with equal voltages, which can realize the longitudinal movement of the moving platform 8; by controlling the longitudinally placed piezoelectric ceramics 9-1 in the two sets of two-axis drive module groups 9 to increase the voltage of one set of piezoelectric ceramics and decrease the voltage of the other set of piezoelectric ceramics by an equal amount, the rotating motion of the moving platform 8 around the two axes of the plane can be realized. In the two-axis drive module group 9, the transversely placed piezoelectric ceramics 9-1 are simultaneously supplied with equal voltages, which can realize the rotation of the moving platform 8; by controlling the transversely placed piezoelectric ceramics 9-1 in the two sets of two-axis drive module groups 9 to increase or decrease the voltage of the two piezoelectric ceramics, the translating motion of the moving platform 8 along the two axes of the plane can be realized. Finally, six-degree-of-freedom motion is achieved.

[0044] Furthermore, the drive unit is connected to a motion control module, which performs inverse kinematics calculations on the control signals to direct the linear drive assembly to control the platform's movement. The motion control module includes a strain sensor or other type of sensor. The strain sensor detects the elongation of the linear drive through the signal generated by its deformation, which serves as the displacement feedback signal for the controller to achieve closed-loop control.

[0045] Example 3

[0046] The difference between this implementation case and Implementation Case 1 and Implementation Case 2 lies in the different driving methods of the drive module, as follows: The linear driver in the drive module can be replaced with a rhombic displacement amplification mechanism, lever displacement amplification mechanism, etc., which have displacement amplification functions to achieve larger displacement movements. It can also be replaced with a piezoelectric drive component with millimeter-level or centimeter-level stroke. The piezoelectric drive form in the drive module can also be replaced with a voice coil drive component, linear motor, or other linear drive components to suit different scenario requirements.

[0047] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0048] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge, characterized in that... include: The system comprises a moving platform, a fixed platform, a drive module assembly, and a motion control module. The drive module assembly consists of a linear actuator and a flexible hinge mechanism. Motion guidance and complete mechanical decoupling are achieved through the elastic deformation of the flexible hinge mechanism. The motion control module is used to drive the platform to achieve six degrees of freedom motion.

2. The spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 1, characterized in that: The drive module assembly consists of eight redundant drive configurations, including four drive modules that provide longitudinal displacement and four drive modules that provide lateral displacement. The linear actuators of the longitudinal and lateral drive modules are arranged orthogonally in space, together providing drive capability for six degrees of freedom motion.

3. The spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 1, characterized in that: The flexible hinge mechanism includes a decoupling flexible hinge and a guiding flexible hinge; the decoupling flexible hinge adopts a two-axis flexible hinge or a two-axis double-through flexible hinge. The two-axis flexible hinge realizes the connection between a single set of drive modules and the moving platform and the decoupling of rotation around two axes. The two-axis double-through flexible hinge realizes the connection between two sets of drive modules and the moving platform and the decoupling of both directions; the guiding flexible hinge is a straight beam moving pair flexible hinge or a quasi-elliptical variable cross-section flexible hinge.

4. The spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 1, characterized in that: The linear actuator is a piezoelectric drive assembly, a voice coil motor drive assembly, or a linear motor; the linear actuator can integrate a rhombic displacement amplification mechanism or a lever displacement amplification mechanism to adapt to micro-nano to centimeter-level stroke requirements.

5. A spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 2, characterized in that: The linear actuators of the drive module assembly are divided into fixed type and floating type; one end of the fixed type drive module is connected to the moving platform through a decoupled flexible hinge, and the other end is fixed to the fixed platform, so its position remains unchanged during operation; both ends of the floating type drive module are connected through a decoupled flexible hinge, so it can swing slightly during operation.

6. The spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 4, characterized in that: The drive module assembly can be replaced by four sets of two-axis drive module groups. Each set of two-axis drive module groups includes two orthogonally arranged linear actuators, an elliptical guide mechanism, a two-axis flexible hinge, and a two-axis double-pass flexible hinge. Each set of two-axis drive module groups can output orthogonal displacement in the horizontal and vertical directions.

7. A spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 4, characterized in that: The motion control module can perform inverse kinematics solutions on external control signals to generate control commands for each linear actuator, driving the motion platform to achieve translation along the X, Y, and Z directions and rotation around the X, Y, and Z axes.

8. A spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 4, characterized in that: The motion control module integrates a strain sensor, which detects the elongation of the linear actuator and generates a displacement feedback signal to achieve closed-loop control of the platform motion.

9. A spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 1, characterized in that: The components of the moving platform, fixed platform, and drive module assembly are all fastened together with screws, and the whole assembly adopts a cubic configuration.

10. A spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge according to claim 1, characterized in that: The spatial six-degree-of-freedom parallel precision motion platform based on a two-axis flexible hinge can achieve rotation of the moving platform around the X-axis or Y-axis by controlling the relative linear actuators to apply equal voltages of "one rising and one falling"; and can achieve rotation of the moving platform around the Z-axis by controlling four sets of linear actuators to "diagonally rise and fall equally".

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