Self-adaptive compliant assembly mechanism for cross-scale micro-components

Abstract

The self-adaptive compliant assembly mechanism for cross-scale micro-components includes a compliant gripping mechanism, a first piezoelectric stack actuator, a second piezoelectric stack actuator, and a compliant cellular jaw, the first gripping arm and the second gripping arm are symmetrically arranged with respect to an axis, and one end of each is connected to a displacement amplification mechanism, the first piezoelectric stack actuator and the second piezoelectric stack actuator (3) are embedded and installed respectively on both sides of the displacement amplification mechanism, and the compliant cellular jaw is detachably installed on the free end of the first gripping arm and the second gripping arm. Compared with conventional assembly mechanisms, the self-adaptive clamping operation can be realized for micro-components with a feature range of microns to millimeters, and has the advantages of compact structure, small size, light weight, etc., and can complete precise assembly of micro-components.

Description

[Technical field]

[0001] The present invention relates to the field of micro-assembly technology, and in particular to a self-adaptive compliant assembly mechanism for cross-scale micro-components. [Background technology]

[0002] Microassembly is a technology that forms a microsystem by assembling tiny components ranging in size from microns to millimeters within a small tolerance range, and is widely used in the processing and manufacturing of products such as medical testing equipment, optical communication components, microsensors, and ultra-small satellite equipment, and is the core and foundation of the micro-nano manufacturing field. Assembly mechanisms are components that directly perform operations such as clamping, transporting, and placing on the micro-assembly objects, and play an important role in microassembly systems, directly restricting the quality and efficiency of microsystem assembly, and affecting the design and development and industrial applications of microelectromechanical systems.

[0003] The compliant mechanism is the most common type of assembly mechanism, which is a mechanical structure that transmits force, displacement and energy by its own elastic deformation, and has the advantages of no assembly required, no gap, no friction, and one-piece molding. However, due to the narrow environment of the micro assembly system and the limited loading capacity of the micromanipulator, the size and weight of the assembly mechanism are always severely restricted, and it is not possible to mount a piezoelectric actuator with a large stroke and a complex displacement amplification mechanism, so it is difficult to realize a large operating stroke.

[0004] However, as microelectromechanical systems develop toward multi-material, multi-function device integration, micromanipulation tasks need to involve microcomponents with different shapes and sizes, whose feature sizes range from microns to millimeters, and the size span far exceeds the maximum working stroke of the assembly mechanism, so that a single assembly mechanism has difficulty in meeting the assembly requirements of complex microelectromechanical systems. The conventional solution is generally to install multiple sets of micromanipulators or microgrippers to realize self-adaptive microassembly for components with different shapes and sizes. For example, the US Lawrence Livermore National Laboratory used six sets of manipulation robot systems to assemble an inertial confinement fusion micro-target involving components with multiple external dimensions, which greatly increases the difficulty and cost of automating the assembly equipment. Therefore, there is an urgent need to develop a self-adaptive assembly mechanism for cross-scale microcomponents. Lofroth and Avci designed a novel modular compliant gripper mechanism that has mounting holes at the end of the gripper mechanism for attaching grip tips applicable to different manipulation objects (Lofroth M, Avci E. Development of a novel modular compliant gripper for manipulation of micro objects[J]. Micromachines, 2019, 10(5):313.). However, the displacement amplification rate is small, the configuration is complicated, the structure size is large, and the gripper tip is easily damaged during the installation process because it is fixed with bolts, and automatic replacement is difficult to realize, which reduces the efficiency of micromanipulation tasks. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to solve the problems of poor versatility and small range of application of traditional assembly mechanisms, and provide a self-adaptive compliant assembly mechanism for cross-scale micro-components. The present invention can realize self-adaptive clamping operations for micro-components with feature sizes ranging from micron to millimeter levels, and has the advantages of compact structure, small size, light weight, etc., can complete precision assembly of micro-components, and can also be used for the self-adaptive assembly of multiple types and multi-batch micro-devices. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a self-adaptive compliant assembly mechanism for cross-scale micro-components, comprising a compliant grip mechanism, a first piezoelectric stack actuator, a second piezoelectric stack actuator, and a compliant cellular jaw; the compliant gripping mechanism has a symmetrical structure and includes a first gripping arm, a second gripping arm, and a displacement amplifying mechanism, the first gripping arm and the second gripping arm are disposed symmetrically with respect to an axis line, and one end of each of the first gripping arm and the second gripping arm is connected to the displacement amplifying mechanism; The first piezoelectric stack actuator and the second piezoelectric stack actuator are embedded and installed on both sides of the displacement amplification mechanism, respectively; The compliant cellular jaws are detachably installed on the free ends of the first gripping arm and the second gripping arm, the compliant cellular jaws are detachably installed, and are easy to assemble and replace, the compliant cellular jaws are replaceable modules, and can realize self-adaptive gripping of micro-components of multiple shapes and sizes, and even after the compliant cellular jaws are lowered, the compliant gripping mechanism can independently grip the micro-components of a certain shape or size.

[0007] Preferably, a first notch and a second notch are provided on either side of the displacement amplification mechanism, and the first piezoelectric stack actuator and the second piezoelectric stack actuator are provided in the first notch and the second notch, respectively.

[0008] Preferably, the compliant grip mechanism further includes a mounting base, the root of the displacement amplification mechanism is connected to the mounting base, and a mounting hole is provided in the mounting base. The microgripper can be mounted to a micromanipulator or a precision positioning stage through the mounting hole.

[0009] Preferably, there is a snap fit between the compliant cellular jaw and the first and second gripping arms.

[0010] Preferably, the first gripping arm and the second gripping arm are provided at their ends with a first gripping surface and a second gripping surface, respectively, which are used not only for positioning and mounting the compliant cellular jaw but also for directly gripping the micro-component, the first gripping surface and the second gripping surface are provided with a first mating portion and a second mating portion, respectively, and the compliant cellular jaw is provided with a first cantilever beam and a second cantilever beam which engage with the first mating portion and the second mating portion, respectively, to unlock or lock the compliant cellular jaw, facilitating quick attachment, detachment and replacement of the compliant cellular jaw.

[0011] Preferably, the compliant cellular jaw has a symmetrical structure and includes a first docking mechanism, a second docking mechanism and a flexible beam, the first docking mechanism and the second docking mechanism are disposed opposite each other and connected by the flexible beam, and the compliant cellular jaw further includes a gripping surface.

[0012] Preferably, the grip surface may be located on the inside of the first docking mechanism, the inside of the second docking mechanism, or the outside of the flexible beam.

[0013] Preferably, each gripping surface is provided with bumps, and when gripping a component, each bump and the component maintain point contact. By providing bumps to maintain point contact with the micro-component, the surface forces such as adhesive force and capillary force between the gripping surface and the micro-component can be reduced, and the gripping stability can be ensured, and the micro-component can be released reliably.

[0014] Preferably, when more than one gripping surface is provided, the tips of the bumps on all gripping surfaces are located on the circumference of the same inscribed circle, and the radius of the inscribed circle is determined by the shape and size of the micro-component. Grip surfaces can be designed to accommodate micro-components of different shapes and sizes.

[0015] Specifically, two flexible beams are installed, and three grip surfaces are installed, which are defined as a third grip surface, a fourth grip surface, and a fifth grip surface, the third grip surface and the fourth grip surface are installed inside the first docking mechanism and the second docking mechanism, respectively, and the fifth grip surface is installed on the outside of the flexible beam, and bumps are installed on both ends of the third grip surface, the fourth grip surface, and the fifth grip surface, and the tips of all the bumps are all located on the circumference of the same inscribed circle, and the radius range of the inscribed circle is from micron to millimeter level, which is suitable for the size of micro-components.

[0016] Preferably, the first docking mechanism and the second docking mechanism are respectively provided with a first docking guide groove and a second docking guide groove, the cross sections of the first docking guide groove and the second docking guide groove match the first grip surface and the second grip surface respectively, and the first grip arm and the second grip arm are respectively detachably connected in the first docking guide groove and the second docking guide groove.

[0017] The overall connection relationship of the modular compliant microgripper used in the above-mentioned micro-assembly is as follows: the first piezoelectric stack actuator and the second piezoelectric stack actuator are respectively mounted in the first notch and the second notch, the engagement relationship is an interference fit, and the clamping of the flexible beam can be realized by calculating the relationship between the clamping force and the interference, and the compliant cellular jaws are mounted on the first grip arm and the second grip arm, and are engaged and locked by the mating part of the grip surface and the cantilever of the docking guide groove. Effect of the Invention

[0018] Compared with the prior art, the beneficial effects of the present invention are at least as follows: (1) The present invention can realize self-adaptive clamping of objects in the micron to millimeter size range by replacing different modular compliant cellular jaws according to the shape and size of the micro-components, and can complete the precision assembly of micro-components. It can also be used for flexible assembly of multi-variety and multi-batch micro-devices. (2) The piezoelectric stack actuator is embedded inside the compliant gripping mechanism, has a large displacement amplification factor and a large operating stroke, is simple and compact in structure, small in size, lightweight, and easy to install and attach to the micromanipulation stage; (3) The compliant gripping mechanism and compliant cellular jaws are snap-fit, with a simple structure, few components, stable connections, and easy to realize automated installation and replacement. (4) The compliant grip mechanism is integrally formed by low-speed wire cutting, has high rigidity, excellent overall integrity, and high motion accuracy. (5) The compliant cellular jaws can grip micro-parts using a multi-grip surface, point-contact method, ensuring stable gripping and reliable release of micro-parts. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is an overall structural diagram of a self-adaptive compliant assembly mechanism for cross-scale micro-components. [Diagram 2] FIG. 13 is a plan view of a compliant grip mechanism. [Diagram 3] FIG. 2 is a schematic diagram of a first gripping arm and a second gripping arm of a compliant gripping mechanism. [Figure 4] FIG. 1 is a schematic diagram of a compliant cellular jaw structure. [Diagram 5] FIG. 2 is a cross-sectional view taken along line AA of a side view of a compliant cellular jaw. [Figure 6] FIG. BB cross-sectional view of the top view of the compliant cellular jaws. [Figure 7] FIG. 13 is a snap-fit ​​schematic of the compliant cellular jaws and compliant gripping mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, specific embodiments of the present invention will be described in more detail in conjunction with the drawings. It should be noted that the specific embodiments are merely illustrative and do not limit the present invention.

[0021] Referring to FIG. 1, the self-adaptive compliant assembly mechanism for cross-scale micro-components provided by the present invention has a replaceable compliant cellular jaw 4, and is applicable to the self-adaptive assembly of micro-components with feature dimensions at the micron to millimeter level, and can complete lot assembly for micro-components, and can also be used for flexible assembly of small lots, multi-variety, and multi-batch micro-devices. Referring to FIG. 1, the self-adaptive compliant assembly mechanism for cross-scale micro-components provided by the present invention includes a compliant grip mechanism 1, a first piezoelectric stack actuator 2, a second piezoelectric stack actuator 3, and a compliant cellular jaw 4.

[0022] In the present invention, referring to FIG. 2, the compliant gripping mechanism 1 is of symmetrical structure, is machined by low speed wire cutting, and includes a first gripping arm 1-1, a second gripping arm 1-2, a displacement amplification mechanism 1-3 and a mounting base 1-4. The first grip arm 1-1 and the second grip arm 1-2 are arranged symmetrically with respect to an axis and are connected to a displacement amplification mechanism 1-3, the base of the displacement amplification mechanism 1-3 is connected to a mounting base 1-4, there are a first notch 1-3-1 and a second notch 1-3-2 on both sides of the displacement amplification mechanism 1-3, the cross-sectional shapes of the first notch 1-3-1 and the second notch 1-3-2 are adapted to the shapes of the piezoelectric stack actuators, the first piezoelectric stack actuator 2 and the second piezoelectric stack actuator 3 are installed in the first notch 1-3-1 and the second notch 1-3-2, respectively, the displacement amplification mechanism 1-3 is used to amplify the output displacement of the piezoelectric actuator, and two mounting holes are drilled in the mounting base 1-4 and are used to mount the compliant assembly mechanism provided by the present invention to another stage.

[0023] In some embodiments of the present invention, the compliant gripping mechanism 1 is a planar symmetric structure. In other embodiments, the gripping mechanism can be arranged to be a three-dimensional axisymmetric structure, and comprise multiple gripping arms.

[0024] In some embodiments of the present invention, the mounting holes are circular through holes.

[0025] In some embodiments of the present invention, the first notch 1-3-1 and the second notch 1-3-2 are located on either side of the center of the displacement amplification mechanism 1-3. The shape of the piezoelectric stack actuator, the first notch 1-3-1 and the second notch 1-3-2 are all rectangular, and of course, in other embodiments, if the shape of the piezoelectric actuator is other, the first notch 1-3-1 and the second notch 1-3-2 are also adjusted according to the shape of the piezoelectric actuator.

[0026] 3, in the present invention, a first grip surface 1-1-1 and a second grip surface 1-2-1 are provided at the ends of the first grip arm 1-1 and the second grip arm 1-2, respectively, and a first mating portion 1-1-2 and a second mating portion 1-2-2 with bumps are provided on the upper surfaces of the roots of the first grip surface 1-1-1 and the second grip surface 1-2-1, respectively, so that the bumps can improve the fastening function. In other embodiments, the snap fit can be provided in other forms or at other positions according to actual needs.

[0027] In some embodiments of the present invention, the cross-sectional shape of the first gripping surface 1-1-1 and the second gripping surface 1-2-1 is wedge-shaped.

[0028] In some embodiments of the present invention, referring to FIG. 4, the compliant cellular jaw 4 has a symmetrical structure and includes a third gripping surface 4-1, a fourth gripping surface 4-2, a fifth gripping surface 4-3, a first flexible beam 4-4, a second flexible beam 4-5, a first docking mechanism 4-6 and a second docking mechanism 4-7, the first docking mechanism 4-6 and the second docking mechanism 4-7 being symmetrically arranged with respect to an axis and connected to each other by the fifth gripping surface 4-3, the first flexible beam 4-4 and the second flexible beam 4-5. The third grip surface 4-1 and the fourth grip surface 4-2 are connected to the first docking mechanism 4-6 and the second docking mechanism 4-7 respectively. The third grip surface 4-1, the fourth grip surface 4-2 and the fifth grip surface 4-3 are all provided with bumps on both ends to maintain point contact with the micro-component and ensure grip stability and reliable release of the micro-component. The tips of the bumps are all located on the circumference of the same inscribed circle, and the radius of the inscribed circle is determined by the micro-component. Thus, grip surfaces can be designed to suit micro-components of different shapes and sizes.

[0029] Here, the function of the flexible beam is to connect the two docking mechanisms and also to increase the stiffness of the whole structure. In other embodiments, one or other quantity of flexible beams can be provided.

[0030] However, the number of gripping surfaces in the compliant cellular jaws 4 can also be set to other values.

[0031] In some embodiments of the present invention, referring to FIG. 5, a first docking guide groove 4-6-1 and a second docking guide groove 4-7-1 are provided in the first docking mechanism 4-6 and the second docking mechanism 4-7, respectively.

[0032] In some embodiments of the present invention, referring to FIG. 6, the first and second docking guide grooves 4-6-1 and 4-7-1 are provided with a first cantilever 4-6-2 and a second cantilever 4-7-2 with bumps at their bases, respectively, to engage with the first and second mating parts 1-1-2 and 1-2-2 to complete the locking of the compliant cellular jaw 4. Here, the docking guide groove can guide the compliant cellular jaw to the mounting position, thereby reducing the requirements for the absolute positioning accuracy of the micromanipulation mechanism and making it easy to realize automatic mounting and replacement. The function of fastening can be enhanced by providing a bump.

[0033] The overall connection relationship of the self-adaptive compliant assembly mechanism of cross-scale micro-components provided in the embodiment of the present invention is as follows: the first piezoelectric stack actuator 2 and the second piezoelectric stack actuator 3 are respectively mounted in the first notch 1-3-1 and the second notch 1-3-2, and the engagement relationship is interference fit, so as to realize the clamping of the flexible beam, and the compliant cellular jaw 4 is mounted on the first grip arm 1-1 and the second grip arm 1-2 and fixed by snapping, referring to FIG. 7, the specific fixing form is that the first grip surface 1-1-1 is inserted into the first docking guide groove 4-6-1 and locked to the first cantilever beam 4-6-2 at the first mating portion 1-1-2, and the second grip surface 1-2-1 is inserted into the second docking guide groove 4-7-1 and locked to the second cantilever beam 4-7-2 at the second mating portion 1-2-2. Here, by embedding the piezoelectric stack actuator inside the compliant gripping mechanism, the position of the actuator and the configuration of the compliant mechanism can be optimized simultaneously, so as to obtain a compliant mechanism with a larger operating stroke; according to the principle of leverage, after the piezoelectric stack actuator is embedded inside the compliant gripping mechanism, the ratio of the power arm to the resistance arm can be made larger, thereby realizing a larger displacement amplification rate and operating stroke.

[0034] The compliant cellular jaw 4 is an interchangeable module, and the bump tips of the third gripping surface 4-1, the fourth gripping surface 4-2 and the fifth gripping surface 4-3 are located on the circumference of the same inscribed circle, and the radius of the inscribed circle conforms to the shape and size of the micro-component, thereby realizing self-adaptive gripping of micro-components of multiple shapes and sizes, and the compliant gripping mechanism 1 can also operate alone, and the first gripping arm 1-1 and the second gripping arm 1-2 clamp the micro-component.

[0035] The operation process of the compliant assembly mechanism provided in the embodiment of the present invention is as follows: First, the compliant assembly mechanism is assembled as shown in the figure, and the compliant assembly mechanism is attached to the micromanipulation stage. When a micro component is to be gripped, a driving voltage is applied to the first piezoelectric stack actuator 2 and the second piezoelectric stack actuator 3, respectively, and the output of the actuator forcibly deforms the displacement amplification mechanism 1-3, and moves the first grip arm 1-1 and the second grip arm 1-2 to move in opposite directions, at this time, a micro component of a fixed size can be gripped. When the compliant cellular jaw 4 is installed, the compliant cellular jaw 4 can also be moved to operate. When the compliant cellular jaw 4 is installed on the compliant grip mechanism 1, the first grip arm 1-1 and the second grip arm 1-2 have a third grip surface 4-1, a fourth grip surface 4-2 and a fifth grip surface 4-3. the third gripping surface 4-1 and the fourth gripping surface 4-2 move in a counter-moving manner perpendicular to the axis, and the direction of movement of the fifth gripping surface 4-3 is parallel to the axis, thereby realizing a three-finger grip on the micro-component; when it is necessary to grip a micro-component of a different size and shape, the original compliant cellular jaw 4 can be removed and replaced with a matching compliant cellular jaw 4, thereby realizing gripping a micro-component of a different size and shape; when the micro-component is to be released, the first piezoelectric stack actuator 2 and the second piezoelectric stack actuator 3 are powered off, the compliant gripping mechanism 1 returns to its original state, the first gripping arm 1-1 and the second gripping arm 1-2 open, and the third gripping surface 4-1, the fourth gripping surface 4-2 and the fifth gripping surface 4-3 are moved to open, thereby releasing the micro-component.

[0036] The above examples of the present invention are merely examples for clearly explaining the present invention, and do not limit the embodiments of the present invention. Those skilled in the art can make other different forms of changes or modifications based on the above description. It is not necessary or possible to cover all the embodiments here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the scope of protection of the claims of the present invention. [Explanation of symbols]

[0037] 1...Compliant grip mechanism, 1-1...First grip arm, 1-1-1...First grip surface, 1-1-2...First mating portion, 1-2...Second grip arm, 1-2-1...Second grip surface, 1-2-2...Second mating portion, 1-3...Displacement amplification mechanism, 1-3-1...First notch, 1-3-2...Second notch, 1-4...Mounting base, 2...First piezoelectric stack actuator, 3...Second piezoelectric stack actuator actuator, 4...compliant cellular jaw, 4-1...third gripping surface, 4-2...fourth gripping surface, 4-3...fifth gripping surface, 4-4...first flexible beam, 4-5...second flexible beam, 4-6...first docking mechanism, 4-6-1...first docking guide groove, 4-6-2...first cantilever beam, 4-7...second docking mechanism, 4-7-1...second docking guide groove, 4-7-2...second cantilever beam.

Claims

1. a compliant gripping mechanism (1), a first piezoelectric stack actuator (2), a second piezoelectric stack actuator (3), and a compliant cellular jaw (4); The compliant grip mechanism (1) has a symmetrical structure and includes a first grip arm (1-1), a second grip arm (1-2), and a displacement amplification mechanism (1-3), the first grip arm (1-1) and the second grip arm (1-2) being arranged symmetrically with respect to an axis, and one end of each being connected to the displacement amplification mechanism (1-3); The first piezoelectric stack actuator (2) and the second piezoelectric stack actuator (3) are embedded and installed on both sides of the displacement amplification mechanism (1-3), respectively; A self-adaptive compliant assembly mechanism for cross-scale micro-components, characterized in that compliant cellular jaws (4) are detachably installed on the free ends of the first grip arm (1-1) and the second grip arm (1-2).

2. The self-adaptive compliant assembly mechanism for cross-scale micro-components of claim 1, characterized in that a first notch (1-3-1) and a second notch (1-3-2) are respectively installed on both sides of the displacement amplification mechanism (1-3), and the first piezoelectric stack actuator (2) and the second piezoelectric stack actuator (3) are respectively installed in the first notch (1-3-1) and the second notch (1-3-2).

3. The self-adaptive compliant assembly mechanism for cross-scale micro-components according to claim 1, characterized in that the compliant gripping mechanism (1) can be installed to be a three-dimensional axisymmetric structure including multiple gripping arms.

4. The self-adaptive compliant assembly mechanism for cross-scale micro-components according to claim 1, characterized in that there is a snap fit between the compliant cellular jaw (4) and the first gripping arm (1-1) and the second gripping arm (1-2).

5. 5. The self-adaptive compliant assembly mechanism for cross-scale micro-components according to claim 4, wherein a first grip surface (1-1-1) and a second grip surface (1-2-1) are provided at the ends of the first grip arm (1-1) and the second grip arm (1-2), respectively, a first mating portion (1-1-2) and a second mating portion (1-2-2) are provided on the first grip surface (1-1-1) and the second grip surface (1-2-1), respectively, and a first cantilever beam (4-6-2) and a second cantilever beam (4-7-2) are provided on the compliant cellular jaw (4) to engage with the first mating portion (1-1-2) and the second mating portion (1-2-2), respectively, to unlock or lock the compliant cellular jaw (4).

6. The self-adaptive compliant assembly mechanism for cross-scale micro-components according to any one of claims 1 to 5, characterized in that the compliant cellular jaw (4) has a symmetrical structure and includes a first docking mechanism (4-6), a second docking mechanism (4-7) and a flexible beam (4-5), the first docking mechanism (4-6) and the second docking mechanism (4-7) are installed opposite each other and are connected between the first docking mechanism (4-6) and the second docking mechanism (4-7) by the flexible beam (4-5), and the compliant cellular jaw (4) further has a gripping surface.

7. The self-adaptive compliant assembly mechanism for cross-scale micro-components according to claim 6, characterized in that the grip surface can be installed on the inside of the first docking mechanism (4-6), the inside of the second docking mechanism (4-7), or the outside of the flexible beam (4-5).

8. The self-adaptive compliant assembly mechanism for cross-scale micro-components as described in claim 7, characterized in that each gripping surface is provided with a bump, and when gripping a component, each bump maintains point contact with the component.

9. The self-adaptive compliant assembly mechanism for cross-scale micro-components described in claim 7, characterized in that when two or more gripping surfaces are installed, the tips of the bumps on all gripping surfaces are located on the circumference of the same inscribed circle, and the radius of the inscribed circle is determined by the shape and size of the micro-component.

10. The self-adaptive compliant assembly mechanism for cross-scale micro-components as described in claim 6, characterized in that the first docking mechanism (4-6) and the second docking mechanism (4-7) are provided with a first docking guide groove (4-6-1) and a second docking guide groove (4-7-1), respectively, and the first gripping arm (1-1) and the second gripping arm (1-2) are detachably connected in the first docking guide groove (4-6-1) and the second docking guide groove (4-7-1), respectively.

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