Double-finger 5-DOF piezoelectric micro gripper and driving method thereof

Abstract

The invention discloses a double-finger 5-DOF piezoelectric micro-gripper and a driving method thereof, belongs to the technical field of micro-nano operation, and particularly relates to the double-finger 5-DOF piezoelectric micro-gripper and the driving method thereof. The problem that the requirement for flexible operation cannot be met due to the fact that an existing piezoelectric micro gripper cannot achieve multi-degree-of-freedom (larger than three degrees of freedom) operation under the condition that large stroke and high precision are both considered is solved. The clamp holder comprises two three-dimensional piezoelectric actuators, two two-dimensional parallelogram flexible structures, a plurality of parallelism adjusting piezoelectric patches and a structure supporting component. The double-finger 5-DOF piezoelectric micro gripper and the driving method thereof are suitable for high-precision clamping and 5-DOF operation of micro objects, and have wide application prospects in the fields of biomedicine, life science, precision manufacturing, micro assembly, advanced optics and the like.

Description

Technical Field

[0001] The present invention relates to the field of micro-nano operation technology, and in particular to a dual-finger 5-DOF piezoelectric micro-gripper and a driving method thereof. Background Art

[0002] The rapid development of life sciences, advanced optics, precision engineering and other fields has put forward more stringent requirements on micro-nano operation technology, which requires not only flexible operation but also high-precision operation.

[0003] As the end effector for micro-nano manipulation tasks, microgrippers need to have large travel, high precision and multiple degrees of freedom. Currently, microgrippers are classified by driving mode, mainly into electrostatic, electromagnetic, electrothermal and piezoelectric types.

[0004] Among them, piezoelectric microgrippers have the advantages of fast response speed, high precision, low energy consumption, compact structure, predictable output displacement and no interference from magnetic fields. They are more suitable for scenarios that require high-precision operations on micro objects, such as biological micromanipulation, including cell separation, cell sorting, cell stiffness measurement, etc., or optical switching assembly based on MEMS chips, or assembly of microcomponents on chip substrates.

[0005] The typical configuration of existing piezoelectric micro-grippers is a piezoelectric stack plus a flexible amplification mechanism, which can achieve large stroke and high-precision operation. However, this typical configuration is limited by the characteristic that the piezoelectric stack can only output one-dimensional linear displacement, and it is difficult to achieve multi-degree-of-freedom operation. The operating degree of freedom of existing piezoelectric micro-grippers is mostly single-degree-of-freedom. In a few cases, 2-DOF (i.e., 2 degrees of freedom) can be achieved by increasing the number of piezoelectric stacks. As for higher degrees of freedom, it is still difficult for those skilled in the art to achieve, which is far from enough to meet the requirements of flexible operation. Summary of the invention

[0006] The present invention proposes a two-finger 5-DOF piezoelectric micro-gripper and a driving method thereof, which solves the problem that the existing piezoelectric micro-gripper cannot achieve multi-degree-of-freedom (greater than 3 degrees of freedom) operation while taking into account a large stroke and high precision, and thus cannot meet the requirements of flexible operation.

[0007] The two-finger 5-DOF piezoelectric micro-gripper described in the present invention has the following technical solution:

[0008] The clamp comprises: two three-dimensional piezoelectric actuators, two two-dimensional parallelogram flexible structures, a plurality of parallelism adjustment piezoelectric sheets and a structural support component;

[0009] The bottom of each three-dimensional piezoelectric actuator is fixed on the structural support component, and the top of each three-dimensional piezoelectric actuator is fixedly connected to the input end of a two-dimensional parallelogram flexible structure; the three-dimensional piezoelectric actuator is used to generate original output displacements along the X-axis direction, the Y-axis direction and the Z-axis direction respectively;

[0010] The fixed end of each two-dimensional parallelogram flexible structure is fixedly connected to the structural support component, and the top end thereof is a fingertip; the top end of the fingertip is a contact surface, and the contact surfaces of the two fingertips are arranged opposite to each other;

[0011] The two-dimensional parallelogram flexible structure is used to transfer the original output displacement of the three-dimensional piezoelectric actuator along the Z-axis direction to the fingertip output, and amplify and guide the original output displacement of the three-dimensional piezoelectric actuator along the X-axis direction and the Y-axis direction, so that the fingertip obtains the final output displacement along the X-axis direction, the Y-axis direction and the Z-axis direction;

[0012] The fingertips of the two two-dimensional parallelogram flexible structures are used to achieve clamping and opening actions, and operate the micro-object to move along the X-axis direction, the Y-axis direction and the Z-axis direction, rotate around the Z-axis direction, and deflect around the Y-axis direction under the coordination of the final output displacement along the X-axis direction, the Y-axis direction and the Z-axis direction;

[0013] The parallelism adjustment piezoelectric sheet is pasted on the surface of the two-dimensional parallelogram flexible structure and is used to adjust the parallelism between the end contact surfaces of the fingertips of the two two-dimensional parallelogram flexible structures.

[0014] Further, a preferred embodiment is provided, wherein the three-dimensional piezoelectric actuator comprises: a stacked pre-tightening screw, a bridge-type amplification structure, a piezoelectric stack, and a bending drive module;

[0015] The piezoelectric stack is embedded in the bridge-type amplification structure, and a stack pre-tightening screw is used to provide a given pre-tightening force to provide a driving displacement along the X-axis direction;

[0016] The bottom of the bridge-type amplifying structure is fixed on the structural support component, and the top of the bridge-type amplifying structure is fixedly connected to the bottom of the bending driving module; the bridge-type amplifying structure is used to amplify and guide the driving displacement along the X-axis direction provided by the piezoelectric stack to obtain the original output displacement along the Z-axis direction;

[0017] The top of the bending driving module is fixedly connected to the input end of a two-dimensional parallelogram flexible structure; the bending driving module is used to provide an original output displacement along the X-axis direction and an original output displacement along the Y-axis direction according to the piezoelectric effect.

[0018] Further, a preferred embodiment is provided, wherein the bending drive module comprises: a bottom end cover, a plurality of four-partition piezoelectric ceramics, a plurality of four-partition electrode sheets, a plurality of ground electrode sheets, a top end cover and a No. 2 pre-tightening screw;

[0019] The bottom end cover, multiple four-partition piezoelectric ceramics, multiple four-partition electrode sheets, multiple ground electrode sheets and the top end cover are stacked in sequence from bottom to top along the Z-axis direction and fixed with No. 2 pre-tightening screws; the top of the top end cover is fixedly connected to the input end of a two-dimensional parallelogram flexible structure;

[0020] Every two partitions of the four-partition piezoelectric ceramics are grouped together, one group of partitions is arranged opposite to each other along the X-axis direction, and the other group of partitions is arranged opposite to each other along the Y-axis direction;

[0021] An excitation signal is used to excite a group of partitions of all four-partition piezoelectric ceramics, so as to make the bending drive module bend and deform along the X-axis direction, and obtain the original output displacement along the X-axis direction;

[0022] The excitation signal is used to excite another group of partitions of all four-partition piezoelectric ceramics, so as to make the bending drive module bend and deform along the Y-axis direction, and obtain the original output displacement along the Y-axis direction.

[0023] Furthermore, a preferred embodiment is provided in which two partitions of the same group of partitions of the four-partition piezoelectric ceramic have opposite polarization directions.

[0024] Further, a preferred embodiment is provided, wherein the fixed end of the two-dimensional parallelogram flexible structure is fixedly connected to the structural support component;

[0025] The input end of the two-dimensional parallelogram flexible structure is fixedly connected to the top of the three-dimensional piezoelectric actuator;

[0026] The top end output end of the two-dimensional parallelogram flexible structure is a fingertip;

[0027] The two-dimensional parallelogram flexible structure is used to guide the original output displacements generated by the three-dimensional piezoelectric actuator along the X-axis direction, the Y-axis direction and the Z-axis direction by utilizing the characteristics of the parallelogram being unstable and easy to deform and the opposite sides always remaining parallel; it is also used to amplify the original output displacements generated by the three-dimensional piezoelectric actuator along the X-axis direction and the Y-axis direction by utilizing the lever principle; it is also used to realize the decoupling of the final output displacements along the X-axis direction, the Y-axis direction and the Z-axis direction by utilizing the characteristic that the longitudinal stiffness of the flexible hinge is much greater than the lateral stiffness.

[0028] Furthermore, a preferred embodiment is provided, wherein the fingertip includes a connecting end at the bottom end, a connecting column at the bottom, a transverse beam in the middle, a thin beam structure at the top, and a clamping column at the top end; the end of the clamping column is a contact surface.

[0029] Furthermore, a preferred embodiment is provided, wherein the plurality of parallelism adjustment piezoelectric sheets are adhered to the fingertip surface of the two-dimensional parallelogram flexible structure to adjust the parallelism between the contact surfaces of the fingertips.

[0030] Further, a preferred embodiment is provided, wherein the clamp further comprises a strain gauge;

[0031] The strain gauge is attached to the thin beam structure of the fingertip and is used to measure the clamping force and provide feedback.

[0032] Further, a preferred embodiment is provided, wherein the structural support component comprises a packaging cover, an outer shell and an inner shell;

[0033] The inner shell includes a circular flat plate at the bottom and a cubic support column located at the center of the circular flat plate;

[0034] Two three-dimensional piezoelectric actuators are symmetrically fixed on the circular plate;

[0035] Two two-dimensional parallelogram flexible structures are symmetrically arranged on both sides of the cubic support column and are respectively fixedly connected to one side of the cubic support column;

[0036] The bottom end surface of the housing is fixedly arranged on the circular flat plate, and the top end surface thereof is fixedly connected to the packaging cover;

[0037] One side plane inner wall of the shell is located on one side of a two-dimensional parallelogram flexible structure, and the two are fixedly connected;

[0038] The other side of the inner plane wall of the shell is located on one side of another two-dimensional parallelogram flexible structure, and the two are fixedly connected.

[0039] The present invention also proposes a driving method for a two-finger 5-DOF piezoelectric micro-gripper, and its technical solution is as follows:

[0040] The driving method is used to drive the above-mentioned two-finger 5-DOF piezoelectric micro-gripper to realize the clamping and opening actions of the contact surfaces of the two fingertips, and to operate the micro-object to move along the X-axis direction, the Y-axis direction and the Z-axis direction, rotate around the Z-axis direction and deflect around the Y-axis direction;

[0041] The driving method shown comprises the following steps:

[0042] Step 1: Excite the original output displacements of two three-dimensional piezoelectric actuators along the X-axis direction to drive them in opposite directions and close to each other, so that the contact surfaces of the two fingertips are opened, which is used to place the micro-object between the two contact surfaces, or to release the clamped micro-object;

[0043] Step 2: Excite the original output displacements of the two three-dimensional piezoelectric actuators along the X-axis direction to drive in opposite directions and away from each other, so that the contact surfaces of the two fingertips are closed, which is used to clamp the micro-object;

[0044] Step 3: The original output displacements of the two three-dimensional piezoelectric actuators along the X-axis are driven in the same direction, so that the contact surfaces of the two fingertips move in the same direction along the X-axis, and the moving direction is opposite to the direction of the original output displacement along the X-axis, so as to manipulate the micro-object to move along the X-axis;

[0045] Step 4: The original output displacements of the two three-dimensional piezoelectric actuators along the Y-axis are driven in the same direction, so that the contact surfaces of the two fingertips move in the same direction along the Y-axis, and the moving direction is opposite to the direction of the original output displacement along the Y-axis, so as to manipulate the micro-object to move along the Y-axis;

[0046] Step 5: The original output displacements of the two three-dimensional piezoelectric actuators along the Z-axis are driven in the same direction, so that the contact surfaces of the two fingertips move in the same direction along the Z-axis, and the moving direction is the same as the direction of the original output displacement along the Z-axis, so as to manipulate the micro-object to move along the Z-axis;

[0047] Step 6: The original output displacements of the two three-dimensional piezoelectric actuators along the Y-axis are stimulated to drive in opposite directions, so that the contact surfaces of the two fingertips move in opposite directions along the Y-axis respectively, so as to twist the micro-object to rotate around the Z-axis;

[0048] Step 7: Excite the original output displacements of the two three-dimensional piezoelectric actuators along the X-axis direction to drive them in opposite directions and away from each other, and at the same time only excite the original output displacement of any one of the three-dimensional piezoelectric actuators along the Z-axis direction, so that the contact surfaces of the two fingertips are closed and moved in an offset manner along the Z-axis direction, which is used to twist the micro-object and deflect it around the Y-axis direction.

[0049] The present invention has the following beneficial effects:

[0050] 1. The dual-finger 5-DOF piezoelectric micro-gripper described in the present invention utilizes a three-dimensional piezoelectric actuator for three-dimensional drive, amplifies and guides the displacement in the XY direction through a two-dimensional parallelogram flexible structure, and decouples it from the displacement in the Z direction. It has the advantages of fast response speed, high precision, low energy consumption, compact structure, predictable output displacement, and no interference from magnetic fields.

[0051] 2. The dual-finger 5-DOF piezoelectric micro-gripper described in the present invention uses a parallelism adjustment piezoelectric sheet to adjust the parallelism of the end contact surface in real time, so that the relative movement of the two contact surfaces always remains parallel, achieving parallel and stable clamping and preventing the clamped object from loosening.

[0052] The two-finger 5-DOF piezoelectric micro-gripper and the driving method thereof described in the present invention are suitable for high-precision clamping and 5-DOF operation of micro-objects, and have broad application prospects in the fields of biomedicine, life sciences, precision manufacturing, micro-assembly, and advanced optics. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0054] Figure 1 1 is a schematic diagram of the structure of a two-finger 5-DOF piezoelectric micro-gripper in one embodiment of the present invention; wherein (a) is a schematic diagram of the appearance of the piezoelectric micro-gripper; (b) is a top view of the piezoelectric micro-gripper after removing the packaging cover; (c) is a schematic diagram of the structure of the piezoelectric micro-gripper after the shell is cut open;

[0055] Figure 2 Schematic diagram of the structure of a three-dimensional piezoelectric actuator in one embodiment of the present invention;

[0056] Figure 3 A schematic diagram of a partition of a four-partition piezoelectric ceramic in one embodiment of the present invention;

[0057] Figure 4 Schematic diagram of the principle of a three-dimensional piezoelectric actuator in one embodiment of the present invention; wherein (a) is a schematic diagram of a bridge-type amplifying structure amplifying and guiding the driving displacement provided by the piezoelectric stack along the X-axis direction (obtaining the original output displacement along the Z-axis direction); (b) is a schematic diagram of the original output displacement provided by the bending driving module along the X (Y) axis direction;

[0058] Figure 5 This is a schematic diagram of a two-dimensional parallelogram flexible structure in one embodiment of the present invention;

[0059] Figure 6 Schematic diagram of the principle of the guiding and amplifying effect of the two-dimensional parallelogram flexible structure in one embodiment of the present invention; wherein (a) is the guiding and amplifying effect of the original output displacement along the X-axis direction; (b) is the guiding and amplifying effect of the original output displacement along the Y-axis direction; (c) is the guiding effect of the original output displacement along the Z-axis direction;

[0060] Figure 7 Schematic diagram of the clamping and opening action of the contact surface of two fingertips in one embodiment of the present invention; wherein (a) is the clamping action, and (b) is the opening action;

[0061] Figure 8 Schematic diagram of the principle of five-degree-of-freedom operation in one embodiment of the present invention; wherein (a) is movement along the X-axis direction, (b) is movement along the Y-axis direction, (c) is movement along the Z-axis direction, (d) is rotation around the Z-axis direction, and (e) is deflection around the Y-axis direction;

[0062] Fig. 9 A schematic diagram of the principle of adjusting the parallelism of a parallelism-adjusting piezoelectric sheet in one embodiment of the present invention;

[0063] Reference numerals:

[0064] 1. Three-dimensional piezoelectric actuator; 1-1. Stack pre-tightening screw; 1-2. Bridge amplification structure; 1-3. Piezoelectric stack; 1-4. Bending drive module; 1-4-1. Bottom cover; 1-4-2. Four-partition piezoelectric ceramic; 1-4-3. Four-partition electrode sheet; 1-4-4. Ground electrode sheet; 1-4-5. Top cover; 1-4-6. No. 2 pre-tightening screw; 2. Two-dimensional parallelogram flexible structure; 2-1. Pillar; 2-2. Flexible hinge; 2-3. Fingertip; 2-3-1. Connecting end; 2-3-2. Connecting column; 2-3-3. Transverse beam; 2-3-4. Thin beam structure; 2-3-5. Clamping column; 3. Parallelism adjustment piezoelectric sheet; 4. Strain gauge; 5. Structural support component; 5-1. Packaging cover; 5-2. Outer shell; 5-3. Inner shell. DETAILED DESCRIPTION

[0065] In order to make the technical solutions and advantages of the present invention more clearly described, the specific implementation methods of the present invention will be further described in detail and completely in conjunction with the accompanying drawings. The various implementation methods described below are only part of the preferred solutions of the present invention, rather than all implementation methods; the various implementation methods described below are intended to explain the present invention and cannot be understood as limitations on the present invention; the reasonable combination of technical features defined in the various implementation methods of the present invention, and all other implementation methods obtained by ordinary technicians in the field without creative work based on the implementation methods of the present invention, are within the scope of protection of the present invention.

[0066] Implementation Method 1: Combination Figures 1 to 9 This embodiment describes a two-finger 5-DOF piezoelectric micro-gripper, and the specific implementation contents are as follows:

[0067] The clamp comprises: two three-dimensional piezoelectric actuators 1, two two-dimensional parallelogram flexible structures 2, a plurality of parallelism adjustment piezoelectric sheets 3 and a structural support component 5;

[0068] The bottom of each three-dimensional piezoelectric actuator 1 is fixed on the structural support component 5, and the top thereof is fixedly connected to the input end of a two-dimensional parallelogram flexible structure 2; the three-dimensional piezoelectric actuator 1 is used to generate original output displacements along the X-axis direction, the Y-axis direction and the Z-axis direction respectively;

[0069] The fixed end of each two-dimensional parallelogram flexible structure 2 is fixedly connected to the structural support component 5, and the top end thereof is a fingertip 2-3; the top end of the fingertip 2-3 is a contact surface, and the contact surfaces of the two fingertips 2-3 are arranged opposite to each other;

[0070] The two-dimensional parallelogram flexible structure 2 is used to transmit the original output displacement of the three-dimensional piezoelectric actuator 1 along the Z-axis direction to the fingertips 2-3 for output, and to amplify and guide the original output displacement of the three-dimensional piezoelectric actuator 1 along the X-axis direction and the Y-axis direction, so that the fingertips 2-3 obtain the final output displacement along the X-axis direction, the Y-axis direction and the Z-axis direction;

[0071] The fingertips 2-3 of the two two-dimensional parallelogram flexible structures 2 are used to achieve clamping and opening actions, and operate the micro-object to move along the X-axis direction, the Y-axis direction and the Z-axis direction, rotate around the Z-axis direction, and deflect around the Y-axis direction under the cooperation of the final output displacement along the X-axis direction, the Y-axis direction and the Z-axis direction;

[0072] The parallelism adjustment piezoelectric sheet 3 is pasted on the surface of the two-dimensional parallelogram flexible structure 2 to adjust the parallelism between the end contact surfaces of the fingertips 2 - 3 of the two two-dimensional parallelogram flexible structures 2 .

[0073] In this embodiment, the 5-DOF (ie 5 degrees of freedom) movement includes: moving along the X-axis direction (positive and negative directions), the Y-axis direction (positive and negative directions) and the positive direction of the Z-axis, rotating around the Z-axis direction and deflecting around the Y-axis direction.

[0074] In this embodiment, if Figure 1 As shown, the positive direction of the X-axis is horizontally toward the right; the positive direction of the Y-axis is horizontally toward the rear; and the positive direction of the Z-axis is vertically toward the upward direction.

[0075] In this embodiment, the original output displacement along the Z-axis direction will not be amplified and guided by the two-dimensional parallelogram flexible structure 2; therefore, the original output displacement along the Z-axis direction and the final output displacement along the Z-axis direction are the same in displacement amount and direction.

[0076] In this embodiment, the original output displacement along the X-axis direction will be amplified and guided by the two-dimensional parallelogram flexible structure 2; therefore, the original output displacement along the X-axis direction and the final output displacement along the X-axis direction are not the same in displacement amount and direction; the displacement amount of the final output displacement along the X-axis direction is greater than the displacement amount of the original output displacement along the X-axis direction; the direction of the final output displacement along the X-axis direction is opposite to the direction of the original output displacement along the X-axis direction, and if the direction of the original output displacement along the X-axis direction is the positive direction along the X-axis direction, then the direction of the final output displacement along the X-axis direction is the negative direction along the X-axis direction.

[0077] In this embodiment, the original output displacement along the Y-axis direction will be amplified and guided by the two-dimensional parallelogram flexible structure 2; therefore, the original output displacement along the Y-axis direction and the final output displacement along the Y-axis direction are not the same in displacement amount and direction; the displacement amount of the final output displacement along the Y-axis direction is greater than the displacement amount of the original output displacement along the Y-axis direction; the direction of the final output displacement along the Y-axis direction is opposite to the direction of the original output displacement along the Y-axis direction. If the direction of the original output displacement along the Y-axis direction is the positive direction along the Y-axis direction, the direction of the final output displacement along the Y-axis direction is the negative direction along the Y-axis direction.

[0078] In this embodiment, the pinching and opening action of the two fingertips 2 - 3 refers to the pinching and opening of the contact surfaces of the two fingertips 2 - 3 .

[0079] In this embodiment, the two fingertips 2 - 3 form a double-finger structure by providing contact surfaces and arranging the two contact surfaces opposite to each other.

[0080] Implementation Method 2: Combination Figures 1 to 9 This embodiment is described as a further limitation of the two-finger 5-DOF piezoelectric micro-gripper described in the first embodiment. The specific implementation contents are as follows:

[0081] The three-dimensional piezoelectric actuator 1 comprises: a stack pre-tightening screw 1-1, a bridge amplification structure 1-2, a piezoelectric stack 1-3 and a bending driving module 1-4;

[0082] The piezoelectric stack 1-3 is embedded in the bridge-type amplifying structure 1-2, and uses the stack pre-tightening screw 1-1 to provide a given pre-tightening force, so as to provide a driving displacement along the X-axis direction;

[0083] The bottom of the bridge-type amplifying structure 1-2 is fixed on the structural support component 5, and the top of the bridge-type amplifying structure 1-2 is fixedly connected to the bottom of the bending driving module 1-4; the bridge-type amplifying structure 1-2 is used to amplify and guide the driving displacement along the X-axis direction provided by the piezoelectric stack 1-3 to obtain the original output displacement along the Z-axis direction;

[0084] The top of the bending driving module 1-4 is fixedly connected to the input end of a two-dimensional parallelogram flexible structure 2; the bending driving module 1-4 is used to provide an original output displacement along the X-axis direction and an original output displacement along the Y-axis direction according to the piezoelectric effect.

[0085] In this embodiment, when the piezoelectric stack 1-3 stretches under the stimulation of the voltage excitation signal (i.e., generates a driving displacement along the X-axis direction), the bridge-type amplification structure 1-2 stretches laterally and widens longitudinally, outputting an original output displacement along the Z-axis direction, and according to the amplification principle, the displacement of the original output displacement along the Z-axis direction is greater than the displacement of the driving displacement along the X-axis direction.

[0086] In this embodiment, the original output displacement along the Z-axis direction obtained by the bridge-type amplification structure 1-2 is transmitted to the two-dimensional parallelogram flexible structure 2 through the bending drive module 1-4 to obtain the final output displacement along the Z-axis direction (compared with the original output displacement, the displacement amount and direction remain unchanged).

[0087] Implementation Method 3: Combination Figures 1 to 9 This embodiment is described as a further limitation of the two-finger 5-DOF piezoelectric micro-gripper described in the second embodiment. The specific implementation contents are as follows:

[0088] The bending drive module 1-4 includes: a bottom end cover 1-4-1, a plurality of four-partition piezoelectric ceramics 1-4-2, a plurality of four-partition electrode sheets 1-4-3, a plurality of grounding electrode sheets 1-4-4, a top end cover 1-4-5 and a No. 2 pre-tightening screw 1-4-6;

[0089] The bottom end cover 1-4-1, multiple four-partition piezoelectric ceramics 1-4-2, multiple four-partition electrode sheets 1-4-3, multiple grounding electrode sheets 1-4-4 and top end cover 1-4-5 are stacked in sequence from bottom to top along the Z-axis direction and fixed with No. 2 pre-tightening screws 1-4-6; the top of the top end cover 1-4-5 is fixedly connected to the input end of a two-dimensional parallelogram flexible structure 2;

[0090] Every two partitions of the four-partition piezoelectric ceramics 1-4-2 are grouped together, one group of partitions is arranged relatively along the X-axis direction, and the other group of partitions is arranged relatively along the Y-axis direction;

[0091] An excitation signal is used to excite a group of partitions of all four-partition piezoelectric ceramics 1-4-2, so as to make the bending drive module 1-4 bend and deform along the X-axis direction, and obtain an original output displacement along the X-axis direction;

[0092] An excitation signal is used to excite another group of partitions of all four-partition piezoelectric ceramics 1-4-2, so as to make the bending drive module 1-4 bend and deform along the Y-axis direction to obtain the original output displacement along the Y-axis direction.

[0093] Furthermore, a preferred embodiment is provided, in which, for a plurality of stacked four-partition piezoelectric ceramics 1-4-2, the partitions of two upper and lower adjacent four-partition piezoelectric ceramics 1-4-2 correspond one to one, and the polarization directions of the two partitions in the same position area are opposite.

[0094] Furthermore, a preferred embodiment is provided in which the polarization directions of two partitions of the same group of partitions of the four-partition piezoelectric ceramic 1-4-2 are opposite.

[0095] Implementation Method 4: Combination Figures 1 to 9 This embodiment is described as a further limitation of the two-finger 5-DOF piezoelectric micro-gripper described in the first embodiment. The specific implementation contents are as follows:

[0096] The fixed end of the two-dimensional parallelogram flexible structure 2 is fixedly connected to the structural support component 5;

[0097] The input end of the two-dimensional parallelogram flexible structure 2 is fixedly connected to the top of the three-dimensional piezoelectric actuator 1;

[0098] The top end output end of the two-dimensional parallelogram flexible structure 2 is a fingertip 2-3;

[0099] The two-dimensional parallelogram flexible structure 2 is used to guide the original output displacements generated by the three-dimensional piezoelectric actuator 1 along the X-axis direction, the Y-axis direction and the Z-axis direction by utilizing the characteristics of the parallelogram being unstable and easy to deform and the opposite sides always remaining parallel; it is also used to amplify the original output displacements generated by the three-dimensional piezoelectric actuator 1 along the X-axis direction and the Y-axis direction by utilizing the lever principle; it is also used to realize the decoupling of the final output displacements along the X-axis direction, the Y-axis direction and the Z-axis direction by utilizing the characteristic that the longitudinal stiffness of the flexible hinge is much greater than the lateral stiffness.

[0100] In this embodiment, each two-dimensional parallelogram flexible structure is mainly composed of an input end, four parallel pillars 2-1, a flexible hinge 2-2 and a fingertip 2-3;

[0101] The bottom of each column 2-1 is connected to the input end via a flexible hinge 2-2 arranged along the Z-axis direction;

[0102] The fixed end of the side surface of the bottom of each column 2-1 is connected to the structural support component 5 through a flexible hinge 2-2 arranged along the X-axis direction;

[0103] The top of each pillar 2-1 is connected to the fingertip 2-3 via a flexible hinge 2-2 arranged along the Z-axis direction.

[0104] In this embodiment, the pillar 2-1 and the input end are equivalent to rigid bodies in theoretical modeling.

[0105] In this embodiment, each two-dimensional parallelogram flexible structure is driven by a corresponding three-dimensional piezoelectric actuator, so each two-dimensional parallelogram flexible structure can independently output the final output displacement along the X-axis direction (positive and negative directions), the Y-axis direction (positive and negative directions) and the positive direction of the Z-axis.

[0106] In this embodiment, the two-dimensional parallelogram flexible structure utilizes the characteristic that the longitudinal stiffness of the flexible hinge is much greater than the transverse stiffness to achieve the decoupling of three-dimensional motion, and utilizes the lever principle and the parallelogram principle to achieve displacement amplification and guidance. The specific principle is: when the input end of the two-dimensional parallelogram flexible structure inputs the displacement in the X direction, the flexible hinge arranged along the X axis does not undergo a large deformation due to the large longitudinal stiffness, thereby playing the role of a fixed fulcrum, and the flexible hinge arranged along the Z axis undergoes bending deformation due to the small transverse stiffness, thereby playing the role of a revolving pair. According to the lever principle and the parallelogram principle, the two-dimensional parallelogram flexible structure amplifies the input displacement and guides it to the fingertip output, thereby achieving the movement in the X direction, and the same is true for the Y direction; when the input end of the two-dimensional parallelogram flexible structure inputs the displacement in the Z direction, the two flexible hinges arranged along the X axis are difficult to deform due to the large longitudinal stiffness, thereby limiting the movement of the parallelogram structure in the X direction, and the transverse stiffness is small and the bending deformation occurs, and the movement of the parallelogram structure in the Z direction is not limited, thereby playing the role of a moving pair. The flexible hinges arranged along the Z direction do not deform due to their large longitudinal stiffness. Therefore, the two-dimensional parallelogram flexible structure is equivalent to a rigid body except for the two flexible hinges arranged along the X axis, which directly transmits the input displacement to the fingertips to achieve Z-direction motion output.

[0107] Implementation Method 5: Combination Figures 1 to 9 This embodiment is described as a further limitation of the two-finger 5-DOF piezoelectric micro-gripper described in the first embodiment. The specific implementation contents are as follows:

[0108] The fingertip 2-3 includes a connecting end 2-3-1 at the bottom end, a connecting column 2-3-2 at the bottom, a transverse beam 2-3-3 in the middle, a thin beam structure 2-3-4 at the top and a clamping column 2-3-5 at the top end; the end of the clamping column 2-3-5 is a contact surface.

[0109] In this embodiment, the contact surface is used to contact with the micro-object to achieve 5-DOF manipulation.

[0110] In this embodiment, the transverse beam 2-3-3 and the thin beam structure 2-3-4 of the fingertip 2-3 are flexible structures such as flexible hinges. The other parts of the fingertip 2-3 are equivalent to rigid bodies in theoretical modeling.

[0111] Implementation Method 6: Combination Figures 1 to 9This embodiment is described as a further limitation of the two-finger 5-DOF piezoelectric micro-gripper described in the first embodiment. The specific implementation contents are as follows:

[0112] The plurality of parallelism adjustment piezoelectric sheets 3 are adhered to the surfaces of the fingertips 2 - 3 of the two-dimensional parallelogram flexible structure 2 , and are used to adjust the parallelism between the contact surfaces of the fingertips 2 - 3 .

[0113] Further, a preferred embodiment is provided.

[0114] The plurality of parallelism adjustment piezoelectric sheets 3 are divided into two groups:

[0115] A set of symmetrically attached to the upper and lower sides of the transverse beam 2-3-3 of the fingertips 2-3 is used to adjust the parallelism of the contact surfaces at the ends of the two fingertips 2-3 in the XZ plane;

[0116] A set of symmetrically attached to the front and rear sides of the transverse beam 2-3-3 of the fingertips 2-3 is used to adjust the parallelism of the contact surfaces at the ends of the two fingertips 2-3 in the XY plane.

[0117] In this embodiment, the upper and lower sides of the transverse beam are the two sides along the Z-axis direction.

[0118] In this embodiment, the front and rear sides of the transverse beam are both sides along the Y-axis direction.

[0119] In this embodiment, the XZ plane refers to a plane parallel to the X-axis and the Z-axis.

[0120] In this embodiment, the XY plane refers to a plane parallel to the X-axis and the Y-axis.

[0121] In this embodiment, the piezoelectric sheets attached to the upper and lower sides of the transverse beam of the fingertip are shortened and elongated under the stimulation of the voltage excitation signal, so that the contact surface at the end of the fingertip rotates a certain angle around the Y axis, which is used to adjust the parallelism of the two contact surfaces in the XZ plane.

[0122] In this embodiment, the piezoelectric sheets attached to the front and rear sides of the transverse beam of the fingertip are shortened and elongated under the stimulation of the voltage excitation signal, so that the contact surface at the end of the fingertip rotates a certain angle around the Z axis, which is used to adjust the parallelism of the two contact surfaces in the XY plane.

[0123] In this embodiment, the piezoelectric sheet 3 is adjusted in parallel so that the two contact surfaces of the clamper and the manipulated micro-object are always kept parallel, thereby achieving stable parallel clamping and reducing stress concentration.

[0124] Implementation Method 7: Combination Figures 1 to 9 This embodiment is described as a further limitation of the two-finger 5-DOF piezoelectric micro-gripper described in Embodiment 5. The specific implementation contents are as follows:

[0125] The clamp also includes a strain gauge 4;

[0126] The strain gauge 4 is attached to the thin beam structure 2-3-4 of the fingertip 2-3 and is used to measure the clamping force and provide feedback.

[0127] In this embodiment, the clamping force is measured and fed back by the strain gauge 4, and the magnitude of the clamping force is further adjusted according to the measurement result.

[0128] Implementation Method 8: Combination Figures 1 to 9 This embodiment is described as a further limitation of the two-finger 5-DOF piezoelectric micro-gripper described in the first embodiment. The specific implementation contents are as follows:

[0129] The structural support component 5 includes a packaging cover 5-1, an outer shell 5-2 and an inner shell 5-3;

[0130] The inner shell 5-3 includes a circular flat plate at the bottom and a cubic support column located at the center of the circular flat plate;

[0131] Two three-dimensional piezoelectric actuators 1 are symmetrically fixed on the circular flat plate;

[0132] Two two-dimensional parallelogram flexible structures 2 are symmetrically arranged on both sides of the cubic support column and are respectively fixedly connected to one side of the cubic support column;

[0133] The bottom end surface of the housing 5-2 is fixedly arranged on a circular flat plate, and the top end surface thereof is fixedly connected to the packaging cover 5-1;

[0134] One side plane inner wall of the housing 5-2 is located on one side of a two-dimensional parallelogram flexible structure 2, and the two are fixedly connected;

[0135] The other side planar inner wall of the shell 5 - 2 is located on one side of another two-dimensional parallelogram flexible structure 2 , and the two are fixedly connected.

[0136] In this embodiment, the cubic support column is a hollow cube.

[0137] Implementation Method 9: Combination Figures 1 to 9 This embodiment describes a driving method of a two-finger 5-DOF piezoelectric micro-gripper. The specific implementation contents are as follows:

[0138] The driving method is used to drive a two-finger 5-DOF piezoelectric micro-gripper described in the above embodiment; to achieve the clamping and opening actions of the contact surfaces of the two fingertips 2-3, and to operate the micro-object to move along the X-axis direction, the Y-axis direction and the Z-axis direction, rotate around the Z-axis direction and deflect around the Y-axis direction;

[0139] The driving method shown comprises the following steps:

[0140] Step 1: Excite the original output displacements of the two three-dimensional piezoelectric actuators 1 along the X-axis direction to drive in opposite directions and close to each other, so that the contact surfaces at the ends of the two fingertips 2-3 are opened, so as to place the micro-object between the two contact surfaces, or to release the clamped micro-object;

[0141] Step 2: Excite the original output displacements of the two three-dimensional piezoelectric actuators 1 along the X-axis direction to drive in opposite directions and away from each other, so that the end contact surfaces of the two fingertips 2-3 are closed, so as to clamp the micro-object;

[0142] Step 3: The original output displacements of the two three-dimensional piezoelectric actuators 1 along the X-axis are stimulated to drive in the same direction, so that the contact surfaces of the two fingertips 2-3 move in the same direction along the X-axis, and the moving direction is opposite to the direction of the original output displacement along the X-axis, so as to manipulate the micro-object to move along the X-axis;

[0143] Step 4: The original output displacements of the two three-dimensional piezoelectric actuators 1 along the Y-axis are stimulated to drive in the same direction, so that the contact surfaces of the two fingertips 2-3 move in the same direction along the Y-axis, and the moving direction is opposite to the direction of the original output displacement along the Y-axis, so as to manipulate the micro-object to move along the Y-axis;

[0144] Step 5: The original output displacements of the two three-dimensional piezoelectric actuators 1 along the Z-axis are stimulated to drive in the same direction, so that the contact surfaces of the two fingertips 2-3 move in the same direction along the Z-axis, and the moving direction is the same as the direction of the original output displacement along the Z-axis, so as to manipulate the micro-object to move along the Z-axis;

[0145] Step 6: The original output displacements of the two three-dimensional piezoelectric actuators 1 along the Y-axis are stimulated to drive in opposite directions, so that the contact surfaces of the two fingertips 2-3 move in opposite directions along the Y-axis, respectively, to twist the micro-object to rotate around the Z-axis.

[0146] Step 7: Excite the original output displacements of the two three-dimensional piezoelectric actuators 1 along the X-axis direction to drive them in opposite directions and away from each other, and at the same time only excite the original output displacement of any one of the three-dimensional piezoelectric actuators 1 along the Z-axis direction, so that the end contact surfaces of the two fingertips 2-3 are closed and displaced along the Z-axis direction, which is used to twist the micro-object and deflect it around the Y-axis direction.

[0147] In this implementation mode, in step 3:

[0148] If the original output displacements of the two three-dimensional piezoelectric actuators 1 along the X-axis direction are both driven along the positive direction of the X-axis direction, the contact surfaces of the two fingertip ends move in the opposite direction of the X-axis direction;

[0149] If the original output displacements of the two three-dimensional piezoelectric actuators 1 along the X-axis direction are both driven in the opposite direction of the X-axis direction, the contact surfaces of the two fingertip ends move in the positive direction of the X-axis direction.

[0150] In this implementation mode, in step 4:

[0151] If the original output displacements of the two three-dimensional piezoelectric actuators 1 along the Y-axis direction are both driven along the positive direction of the Y-axis direction, the contact surfaces of the two fingertip ends move in the opposite direction of the Y-axis direction;

[0152] If the original output displacements of the two three-dimensional piezoelectric actuators 1 along the Y-axis direction are both driven in the opposite direction of the Y-axis direction, the contact surfaces of the two fingertip ends move in the positive direction of the Y-axis direction.

[0153] In this implementation mode, in step 5:

[0154] Since the piezoelectric stack can only be stretched and deformed, the original output displacement in the Z direction can only be in the positive direction, that is, the original output displacements along the Z axis direction of the two three-dimensional piezoelectric actuators 1 are driven in the positive direction of the Z axis direction, and the contact surfaces of the two fingertip ends move in the positive direction of the Z axis direction;

[0155] In this implementation mode, in step 6:

[0156] If the original output displacements of the two three-dimensional piezoelectric actuators 1 along the Y-axis direction are driven in opposite directions, that is, one of them is driven in the positive direction of the Y-axis direction and the other is driven in the negative direction of the Y-axis direction, then one of the contact surfaces at the ends of the two fingertips moves in the negative direction of the Y-axis direction and the other moves in the positive direction of the Y-axis direction, thereby twisting the micro-object to rotate clockwise or counterclockwise around the Z-axis direction.

[0157] The technical solution provided by the present invention is further described in detail above through several specific implementation modes in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific implementation modes described above are not intended to be used as limitations on the present invention. Any reasonable changes and improvements to the present invention, reasonable combinations of implementation modes and equivalent substitutions based on the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A two-finger 5-DOF piezoelectric micro-gripper, characterized in that: The clamp comprises: two three-dimensional piezoelectric actuators (1), two two-dimensional parallelogram flexible structures (2), a plurality of parallelism adjustment piezoelectric sheets (3) and a structural support component (5); The bottom of each three-dimensional piezoelectric actuator (1) is fixed on a structural support component (5), and the top of each three-dimensional piezoelectric actuator (1) is fixedly connected to the input end of a two-dimensional parallelogram flexible structure (2); the three-dimensional piezoelectric actuator (1) is used to generate original output displacements along the X-axis direction, the Y-axis direction and the Z-axis direction respectively; The fixed end of each two-dimensional parallelogram flexible structure (2) is fixedly connected to the structural support component (5), and the top end thereof is a fingertip (2-3); the top end of the fingertip (2-3) is a contact surface, and the contact surfaces of the two fingertips (2-3) are arranged opposite to each other; The two-dimensional parallelogram flexible structure (2) is used to transmit the original output displacement of the three-dimensional piezoelectric actuator (1) along the Z-axis direction to the fingertip (2-3) for output, and to amplify and guide the original output displacement of the three-dimensional piezoelectric actuator (1) along the X-axis direction and the Y-axis direction, so that the fingertip (2-3) obtains the final output displacement along the X-axis direction, the Y-axis direction and the Z-axis direction; The fingertips (2-3) of the two two-dimensional parallelogram flexible structures (2) are used to realize clamping and opening actions in coordination with the final output displacements along the X-axis direction, the Y-axis direction and the Z-axis direction, and to operate the micro-object to move along the X-axis direction, the Y-axis direction and the Z-axis direction, rotate around the Z-axis direction and deflect around the Y-axis direction; The parallelism adjustment piezoelectric sheet (3) is adhered to the surface of the two-dimensional parallelogram flexible structure (2) and is used to adjust the parallelism between the end contact surfaces of the fingertips (2-3) of the two two-dimensional parallelogram flexible structures (2).

2. A two-finger 5-DOF piezoelectric micro-gripper according to claim 1, characterized in that: The three-dimensional piezoelectric actuator (1) comprises: a stacked pre-tightening screw (1-1), a bridge-type amplification structure (1-2), a piezoelectric stack (1-3) and a bending drive module (1-4); The piezoelectric stack (1-3) is embedded in the bridge-type amplifying structure (1-2), and uses the stack pre-tightening screw (1-1) to provide a given pre-tightening force, so as to provide a driving displacement along the X-axis direction; The bottom of the bridge-type amplifying structure (1-2) is fixed on the structural support component (5), and the top of the bridge-type amplifying structure (1-2) is fixedly connected to the bottom of the bending driving module (1-4); the bridge-type amplifying structure (1-2) is used to amplify and guide the driving displacement along the X-axis direction provided by the piezoelectric stack (1-3) to obtain the original output displacement along the Z-axis direction; The top of the bending drive module (1-4) is fixedly connected to the input end of a two-dimensional parallelogram flexible structure (2); the bending drive module (1-4) is used to provide an original output displacement along the X-axis direction and an original output displacement along the Y-axis direction according to the piezoelectric effect.

3. A two-finger 5-DOF piezoelectric micro-gripper according to claim 2, characterized in that: The bending drive module (1-4) comprises: a bottom end cover (1-4-1), a plurality of four-partition piezoelectric ceramics (1-4-2), a plurality of four-partition electrode sheets (1-4-3), a plurality of grounding electrode sheets (1-4-4), a top end cover (1-4-5) and No. 2 pre-tightening screws (1-4-6); The bottom end cover (1-4-1), a plurality of four-partition piezoelectric ceramics (1-4-2), a plurality of four-partition electrode sheets (1-4-3), a plurality of grounding electrode sheets (1-4-4) and a top end cover (1-4-5) are stacked in sequence from bottom to top along the Z-axis direction and fixed with No. 2 pre-tightening screws (1-4-6); the top of the top end cover (1-4-5) is fixedly connected to the input end of a two-dimensional parallelogram flexible structure (2); Every two partitions of the four-partition piezoelectric ceramic (1-4-2) are grouped together, one group of partitions is arranged opposite to each other along the X-axis direction, and the other group of partitions is arranged opposite to each other along the Y-axis direction; An excitation signal is used to excite a group of partitions of all four partitioned piezoelectric ceramics (1-4-2) to cause the bending drive module (1-4) to bend and deform along the X-axis direction, thereby obtaining an original output displacement along the X-axis direction; An excitation signal is used to excite another group of partitions of all four partitioned piezoelectric ceramics (1-4-2) to cause the bending drive module (1-4) to bend and deform along the Y-axis direction, thereby obtaining an original output displacement along the Y-axis direction.

4. A two-finger 5-DOF piezoelectric micro-gripper according to claim 3, characterized in that: The polarization directions of two partitions of the same group of partitions in the four-partition piezoelectric ceramic (1-4-2) are opposite.

5. A two-finger 5-DOF piezoelectric micro-gripper according to claim 1, characterized in that: The fixed end of the two-dimensional parallelogram flexible structure (2) is fixedly connected to the structural support component (5); The input end of the two-dimensional parallelogram flexible structure (2) is fixedly connected to the top of the three-dimensional piezoelectric actuator (1); The top end output end of the two-dimensional parallelogram flexible structure (2) is a fingertip (2-3); The two-dimensional parallelogram flexible structure (2) is used to guide the original output displacements generated by the three-dimensional piezoelectric actuator (1) along the X-axis direction, the Y-axis direction and the Z-axis direction by utilizing the characteristics of the parallelogram being unstable and easy to deform and the opposite sides always remaining parallel; it is also used to amplify the original output displacements generated by the three-dimensional piezoelectric actuator (1) along the X-axis direction and the Y-axis direction by utilizing the principle of a lever; and it is also used to achieve decoupling of the final output displacements along the X-axis direction, the Y-axis direction and the Z-axis direction by utilizing the characteristic that the longitudinal stiffness of the flexible hinge is much greater than the transverse stiffness.

6. A two-finger 5-DOF piezoelectric micro-gripper according to claim 1, characterized in that: The fingertip (2-3) comprises a connecting end (2-3-1) located at the bottom end, a connecting column (2-3-2) located at the bottom, a transverse beam (2-3-3) located in the middle, a thin beam structure (2-3-4) located at the top, and a clamping column (2-3-5) located at the top end; the end of the clamping column (2-3-5) is a contact surface.

7. A two-finger 5-DOF piezoelectric micro-gripper according to claim 1, characterized in that: The plurality of parallelism adjustment piezoelectric sheets (3) are adhered to the surfaces of the fingertips (2-3) of the two-dimensional parallelogram flexible structure (2) and are used to adjust the parallelism between the contact surfaces of the fingertips (2-3).

8. A two-finger 5-DOF piezoelectric micro-gripper according to claim 6, characterized in that: The clamp also includes a strain gauge (4); The strain gauge (4) is adhered to the thin beam structure (2-3-4) of the fingertip (2-3) and is used to measure the clamping force and provide feedback.

9. A two-finger 5-DOF piezoelectric micro-gripper according to claim 1, characterized in that: The structural support component (5) comprises a packaging cover (5-1), an outer shell (5-2) and an inner shell (5-3); The inner shell (5-3) comprises a circular flat plate at the bottom and a cubic support column located at the center of the circular flat plate; Two three-dimensional piezoelectric actuators (1) are symmetrically fixed on the circular plate; Two two-dimensional parallelogram flexible structures (2) are symmetrically arranged on both sides of the cubic support column and are respectively fixedly connected to one side of the cubic support column; The bottom end surface of the housing (5-2) is fixedly arranged on a circular flat plate, and the top end surface thereof is fixedly connected to the packaging cover (5-1); One side plane inner wall of the shell (5-2) is located on one side of a two-dimensional parallelogram flexible structure (2), and the two are fixedly connected; The other side planar inner wall of the shell (5-2) is located on one side of another two-dimensional parallelogram flexible structure (2), and the two are fixedly connected.

10. A method for driving a two-finger 5-DOF piezoelectric micro-gripper, characterized in that: The driving method is used to drive a two-finger 5-DOF piezoelectric micro-gripper as described in any one of claims 1 to 9, so as to realize the clamping and opening actions of the contact surfaces at the ends of the two fingertips (2-3), and to operate the micro-object to move along the X-axis direction, the Y-axis direction and the Z-axis direction, rotate around the Z-axis direction and deflect around the Y-axis direction; The driving method shown comprises the following steps: Step 1: Excite the original output displacements of two three-dimensional piezoelectric actuators (1) along the X-axis direction to drive them in opposite directions and close to each other, so that the contact surfaces at the ends of the two fingertips (2-3) are opened, so as to place the micro-object between the two contact surfaces, or to release the clamped micro-object; Step 2: Exciting the original output displacements of the two three-dimensional piezoelectric actuators (1) along the X-axis direction to drive them in opposite directions and away from each other, so that the contact surfaces at the ends of the two fingertips (2-3) are closed, so as to clamp the micro-object; Step 3: The original output displacements of the two three-dimensional piezoelectric actuators (1) along the X-axis are driven in the same direction, so that the contact surfaces of the two fingertips (2-3) move in the same direction along the X-axis, and the moving direction is opposite to the direction of the original output displacement along the X-axis, so as to manipulate the micro-object to move along the X-axis; Step 4: The original output displacements of the two three-dimensional piezoelectric actuators (1) along the Y-axis are driven in the same direction, so that the contact surfaces of the two fingertips (2-3) move in the same direction along the Y-axis, and the moving direction is opposite to the direction of the original output displacement along the Y-axis, so as to manipulate the micro-object to move along the Y-axis; Step 5: The original output displacements of the two three-dimensional piezoelectric actuators (1) along the Z-axis are driven in the same direction, so that the contact surfaces of the two fingertips (2-3) move in the same direction along the Z-axis, and the moving direction is the same as the direction of the original output displacement along the Z-axis, so as to manipulate the micro-object to move along the Z-axis; Step 6: Excite the original output displacements of the two three-dimensional piezoelectric actuators (1) along the Y-axis direction to drive in opposite directions, so that the contact surfaces of the two fingertips (2-3) move in opposite directions along the Y-axis direction, so as to twist the micro-object to rotate around the Z-axis direction; Step 7: The original output displacements of the two three-dimensional piezoelectric actuators (1) along the X-axis are stimulated to be driven in opposite directions and away from each other, and at the same time, only the original output displacement of any one of the three-dimensional piezoelectric actuators (1) along the Z-axis is stimulated, so that the contact surfaces at the ends of the two fingertips (2-3) are closed and displaced along the Z-axis, so as to twist the micro-object and deflect it around the Y-axis.

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