A multi-degree-of-freedom micro-robot across scales

Abstract

The application discloses a cross-scale multi-degree-of-freedom micro-robot, which comprises a clamping driving unit and a three-degree-of-freedom rotary driving unit, wherein the three-degree-of-freedom rotary driving unit comprises three-stage rotary tables, each stage rotary table is driven by a rotary piezoelectric driving unit with the same structure; the rotary piezoelectric driving unit and the clamping driving unit are driven by independent periodic excitation signals, and net displacement or net rotation angle is generated in one working cycle. In view of the problem that the service life of the driving device is limited due to friction and wear in the piezoelectric cross-scale friction transmission, the application introduces a magnetic coupling wear self-adaptive compensation mechanism, after the friction plate or the shaft ring is worn, under the multiple forces of the repulsive force between the driving magnet and the pre-tightening magnet and the adsorption force between the driving magnet and the shaft ring, the friction plate always keeps stable contact with the shaft ring and maintains relatively stable friction force; cross-scale precise motion and long-time service are realized.

Description

Technical Field

[0001] This invention belongs to the field of micro-operation robots, specifically relating to a long-life, multi-scale, multi-degree-of-freedom micro-operation robot. Background Technology

[0002] Micro-operations are widely used in precision manipulation, biomedical engineering, and micro / nano manufacturing. Among them, piezoelectric-driven micro-operations have attracted widespread attention due to their advantages such as fast response speed, high positioning accuracy, and absence of magnetic interference. Currently, mainstream piezoelectric-driven micro-operations utilize the inverse piezoelectric effect, achieving micron- to nanometer-scale stepping motion through periodic electrical signal excitation. These robots typically include linear motion mechanisms, rotary motion mechanisms, and multi-degree-of-freedom composite motion mechanisms to meet the needs of various application scenarios.

[0003] Despite the excellent performance of existing piezoelectric-driven microrobots in terms of precision and dynamics, the following technical bottlenecks still exist:

[0004] Poor cross-scale adaptability: Existing micro-operation robots are usually optimized for specific scales, and their motion performance is difficult to maintain when applied across scales (such as from micrometer-level manipulation to millimeter-level movement).

[0005] Limited lifespan: During long-term operation, the drive mechanism (such as friction pairs) of traditional multi-scale micro-operation robots is susceptible to wear, leading to performance degradation and reducing the reliability and lifespan of the equipment;

[0006] Limited degrees of freedom: Existing designs are mostly limited to one or a few degrees of freedom, which makes it difficult to meet the needs of complex operations and limits their applicability in high-precision control;

[0007] Insufficient wear compensation capability: Due to the accumulation of friction and wear, existing systems often lead to friction drive failure after long-term operation, lacking an effective adaptive compensation mechanism; CN202411607812.2 discloses a durable triaxial drive mechanism for a cell minimally invasive puncture instrument, which achieves friction and wear adaptation through cascaded magnet configuration, but requires three cascaded magnets for coupling, and the piezoelectric ceramic will bear additional tensile and shear stress when driven, and excessive amplitude will cause damage to the piezoelectric ceramic, so it is necessary to use piezoelectric ceramic with a protective shell, which increases the size and complexity of the system. Summary of the Invention

[0008] To address the problems in existing technologies, this invention proposes a long-life, multi-scale, multi-degree-of-freedom microrobot, the technical solution of which is as follows:

[0009] A long-life, multi-scale, multi-DOF micro-operation robot includes a gripping drive unit and a three-DOF rotation drive unit. The three-DOF rotation drive unit comprises a first rotary table, a second rotary table, and a third rotary table, each with a base. The first rotary table is horizontally arranged on its base, and its output end is fixedly connected to the base of the second rotary table, driving the second rotary table and its base to rotate about the vertical direction. The output end of the second rotary table is connected to the base of the third rotary table, driving the third rotary table and its base to rotate in the vertical plane. The output end of the third rotary table is connected to the gripping drive unit, driving the gripping drive unit to rotate in the vertical plane. The first, second, and third rotary tables are driven by identical rotary piezoelectric drive units.

[0010] The clamping drive unit includes a clamp, a slider, a clamping plate, a clamping piezoelectric ceramic, a clamping rod, and a carbon fiber rod. One end of the clamping rod is fixed to the output end of the third rotary table. A clamping piezoelectric ceramic is fixedly installed on both sides of the other end. A clamping plate is fixedly connected to the movable end of the clamping piezoelectric ceramic. Two carbon fiber rods are fixed to the inner sides of the two clamping plates respectively. The two carbon fiber rods are arranged facing each other and there is a distance between their ends. Two sliders are respectively sleeved on the two carbon fiber rods and fixed to the carbon fiber rods under the action of pre-tightening force. The two parts of the clamp are respectively connected to the two sliders.

[0011] According to a specific embodiment of the present invention, the clamping drive unit further includes a spring and a clamping preload screw; the slider includes an upper slider plate and a lower slider plate connected to each other, the upper slider plate and the lower slider plate are installed in parallel, forming a carbon fiber rod mounting groove between them, a slider boss is provided on the wall surface of the lower slider plate side in the carbon fiber rod mounting groove, the upper slider plate is provided with a slider through hole in the thickness direction, and the lower slider plate is provided with a slider threaded hole at the position directly opposite the slider through hole; after the carbon fiber rod is inserted into the carbon fiber rod mounting groove, the clamping preload screw is passed through the spring and the slider through hole and screwed into the slider threaded hole, and the friction between the slider and the carbon fiber rod is adjusted by the tightening degree of the clamping preload screw.

[0012] According to a specific embodiment of the present invention, the clamping drive unit is driven by a periodic excitation signal, and one working cycle of the periodic excitation signal includes a stationary phase, a sticking phase, and a sliding phase; wherein, during the stationary phase, the excitation signal is zero, and the clamping drive unit is stationary;

[0013] During the adhesion stage, the input voltage of the excitation signal changes slowly. During this stage, the clamping piezoelectric ceramic elongates or retracts with the slow change of voltage. The combination of the clamping plate and the carbon fiber rod moves slowly. Due to the friction between the combination and the slider under the pre-tightening force, and because of the slow movement during this stage, the friction is static friction. Under the action of static friction, the combination drives the two sliders to move a distance d1 respectively.

[0014] During the sliding phase, the input voltage of the excitation signal changes rapidly. During this phase, the clamping piezoelectric ceramic rapidly elongates or contracts with the rapid change of voltage, and the assembly also moves rapidly. Due to the rapid movement during this phase, relative motion will occur between the assembly and the slider. The friction force is dynamic friction. Under the action of dynamic friction, the two sliders will each have a small retraction displacement Δd, and the slider movement distance is reduced to d2.

[0015] The voltage changes in the sticking and sliding stages are opposite in direction, so the piezoelectric ceramic and the slider move in opposite directions in the two stages; within one cycle, each slider gains a net displacement, the net displacement d2 = d1 - Δd, and the distance the two parts of the clamp of the clamping drive unit move is 2 × d2.

[0016] According to a specific embodiment of the present invention, the axis of the first rotary table is vertical, and its output end rotates about the axis; the bases of the second and third rotary tables each include a base extension plate, the length direction of which passes through the rotation center of the rotary table; the base extension plate of the second rotary table is installed at the output end of the first rotary table, and the length direction of the base extension plate is collinear with the axis of the first rotary table.

[0017] The axis of the second rotary table is horizontal. The base extension plate of the third rotary table is installed at the output end of the second rotary table and is perpendicular to the axis of the second rotary table. The axis of the third rotary table is horizontal. One end of the clamping rod is fixed on the third rotary table, and the length of the clamping rod is perpendicular to the axis of the third rotary table.

[0018] According to a specific embodiment of the present invention, the rotary piezoelectric drive unit includes a collar, a friction plate, a preload magnet, a piezoelectric ceramic, and a drive magnet;

[0019] The fixed end of the piezoelectric ceramic and the pre-tightening magnet are both fixed on the mounting base of the rotary piezoelectric drive unit. The movable end of the piezoelectric ceramic is driven by an external excitation signal to extend or retract along a preset motion direction. The pre-tightening magnet is positioned opposite the movable end of the piezoelectric ceramic, with a distance between them. The drive magnet and the friction plate are bonded together, and the combined body is positioned between the pre-tightening magnet and the movable end of the piezoelectric ceramic. The collar is made of ferromagnetic material, and the drive magnet and the collar are attracted by magnetic force, fixing the friction plate between them. Both the drive magnet and the pre-tightening magnet are single-stage magnetized, and their internal magnetic fields are in opposite directions. When the piezoelectric ceramic is driven by an excitation signal, under the action of the repulsive force between the drive magnet and the pre-tightening magnet and the attraction force between the drive magnet and the collar, the drive magnet can only adhere to the movable end of the piezoelectric ceramic and drive the shaft to rotate around its axis.

[0020] According to a specific embodiment of the present invention, the collar includes an inner ring and an outer ring that are rotatable relative to each other. The inner ring of the collar is fixed on the base of the corresponding rotary table, and a combination of a friction plate and a driving magnet is connected to the outer ring of the collar. The output end of the corresponding rotary table is fixedly connected to the outer ring of the collar. The axial direction of the collar is the axial direction of the corresponding rotary table.

[0021] According to a specific embodiment of the present invention, the rotary piezoelectric drive unit is driven by a periodic excitation signal, and one working cycle of the periodic excitation signal includes a stationary phase, a sticking phase, and a sliding phase; wherein, during the stationary phase, the excitation signal is zero, and the clamping drive unit is stationary;

[0022] During the adhesion stage, the input voltage of the excitation signal changes slowly. During this stage, the piezoelectric ceramic elongates or retracts with the slow change in voltage, driving the combination of magnet and friction plate to move slowly. Due to the friction between the combination and the collar under the preload, and because of the slow movement during this stage, the friction is static friction. Under the action of static friction, the combination drives the collar to rotate by an angle θ1.

[0023] During the sliding phase, the input voltage of the excitation signal changes rapidly. During this phase, the piezoelectric ceramic elongates or contracts rapidly with the rapid change of voltage, and the assembly also moves rapidly. Due to the rapid movement during this phase, relative movement will occur between the assembly and the collar, and the friction force is dynamic friction. Under the action of dynamic friction, the collar rotates by an angle θ2.

[0024] The voltage changes in the sticking and sliding stages are opposite in direction, so the piezoelectric ceramic moves in opposite directions in the two stages, and the corresponding collar rotates in opposite directions in the two stages; within one cycle, the collar obtains a net rotation angle Δθ=θ1-θ2.

[0025] According to a specific embodiment of the present invention, the output end of the second rotary table is further provided with a counterweight, which is installed on the extension line of the base extension plate of the third rotary table to balance the weight of the third rotary table.

[0026] The output end of the third rotary table is also equipped with a counterweight, which is installed on the extension line of the clamping rod to balance the weight of the clamping drive unit.

[0027] According to a specific embodiment of the present invention, the clamping drive unit, as well as the rotary piezoelectric drive units of the first rotary table, the second rotary table, and the third rotary table, are driven by independent excitation signals respectively.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention provides a long-life, multi-scale, multi-degree-of-freedom micro-operation robot, significantly improving its service life. By introducing a magnetic coupling wear adaptive compensation mechanism, the invention effectively reduces the wear impact of friction pairs. Even after wear on the friction plates or collar, the friction plates maintain stable contact with the collar and a relatively stable frictional force under the combined forces of the repulsive force between the driving magnet and the pre-tightening magnet, and the attraction force between the driving magnet and the collar. It achieves precise cross-scale motion: employing an optimized piezoelectric drive scheme, the robot can achieve high-precision motion in the micrometer and nanometer scales, and maintain stable stepping and positioning in the millimeter scale through high-frequency periodic excitation, achieving cross-scale adaptability. It increases motion degrees of freedom: the design features a multi-degree-of-freedom drive structure, supporting more complex motion modes, meeting the needs of high-precision micro-manipulation, and broadening application scenarios. This robot can be widely used in fields such as biological cell manipulation, micro / nano manufacturing, and precision assembly, suitable for high-precision and long-term stable operation. This invention provides a new solution for the development of high-precision micro-operation robot technology, improving the capabilities of micro-operation robots in terms of long lifespan, cross-scale adaptability, and high-degree-of-freedom manipulation, possessing significant engineering application value and industrialization prospects. Attached Figure Description

[0030] Figure 1 A schematic diagram of a long-life, multi-scale, multi-degree-of-freedom microrobot.

[0031] Figure 2 This is a schematic diagram of the clamping drive unit;

[0032] Figure 3 This is a schematic diagram of the slider structure;

[0033] Figure 4 This is a schematic diagram of the clamping plate structure;

[0034] Figure 5 This is a schematic diagram of the clamping rod structure;

[0035] Figure 6 This is a schematic diagram of a three-degree-of-freedom rotational drive unit.

[0036] Figure 7 This is a schematic diagram of the first rotary table structure;

[0037] Figure 8 This is a schematic diagram of the base structure of the first rotating platform;

[0038] Figure 9 This is a schematic diagram of the base structure of the second rotating platform;

[0039] Figure 10 A schematic diagram of the output end cover structure of the third rotary table;

[0040] Figure 11This is a schematic diagram illustrating the working principle of a long-life, multi-scale, multi-degree-of-freedom microrobot. Detailed Implementation

[0041] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0042] A schematic diagram of the long-life, multi-scale, multi-degree-of-freedom microrobot designed in this invention is shown below. Figure 1 As shown, it mainly includes a clamping drive unit 1-1 and a three-degree-of-freedom rotation drive unit 1-2, which are connected by screws.

[0043] The three-degree-of-freedom rotation drive unit 1-2 provides three degrees of freedom for the multi-degree-of-freedom micro-operation robot. In a specific embodiment of the present invention, as shown... Figure 6 As shown, the three-degree-of-freedom rotary drive unit includes a first rotary table 1-2-1, a second rotary table 1-2-2, and a third rotary table 1-2-3, each with a base. The first rotary table is horizontally arranged on its base 1-2-1-1, and its output end is fixedly connected to the base 1-2-7 of the second rotary table, driving the second rotary table and its base to rotate in the vertical direction. The output end of the second rotary table is connected to the base of the third rotary table, driving the third rotary table and its base to rotate in the vertical plane. The output end of the third rotary table is connected to the clamping drive unit 1-1, driving the clamping drive unit to rotate in the vertical plane. The first, second, and third rotary tables are driven by rotary piezoelectric drive units with identical structures.

[0044] The clamping drive unit 1-1 is the end effector of a multi-degree-of-freedom micro-operation robot, such as... Figures 2 to 5 As shown, in one specific embodiment, the clamping drive unit 1-1 includes a clamp 1-1-1, a slider 1-1-2, a clamping plate 1-1-3, a clamping piezoelectric ceramic 1-1-4, a clamping rod 1-1-5, a spring 1-1-6, a clamping preload screw 1-1-7, and a carbon fiber rod 1-1-8.

[0045] See Figure 2 The clamp 1-1-1 is used to clamp an object. It includes two clamping arms with identical structures and symmetrical arrangement. One end of each clamping arm is fixed to two sliders 1-1-2. The other ends of the two clamping arms are suspended and close to each other. The distance between the suspended ends of the two clamping arms can be controlled by moving the sliders, thereby clamping or releasing the object. In the embodiment of the present invention, the clamping arms are set as thin plates, and their material can be selected according to actual needs.

[0046] like Figure 3As shown, the slider includes an upper slider plate 1-1-2-2 and a lower slider plate connected to each other by slider hinges 1-1-2-6. The upper slider plate 1-1-2-2 and the lower slider plate are installed in parallel, forming a carbon fiber rod mounting groove between them. A slider boss 1-1-2-4 is provided on the wall of the lower slider plate side in the carbon fiber rod mounting groove. The upper slider plate 1-1-2-2 is provided with a slider through hole 1-1-2-1 penetrating the upper slider plate in the thickness direction. A slider threaded hole 1 is provided on the lower slider plate at a position directly opposite the slider through hole. -1-2-3; After the carbon fiber rod 1-1-8 is installed into the carbon fiber rod mounting slot, the clamping pre-tightening screw 1-1-7 is passed through the spring 1-1-6 and the slider through hole 1-1-2-1 and screwed into the slider threaded hole 1-1-2-3. The friction between the slider 1-1-2 and the carbon fiber rod 1-1-8 is adjusted by the tightness of the clamping pre-tightening screw. The slider hinge 1-1-2-6 makes it easy to adjust the distance between the upper slider plate 1-1-2-2 and the lower slider plate to achieve the adjustment of the pre-tightening force.

[0047] like Figure 5 As shown, the clamping rod is a long strip rod of a certain length. One end of the rod is fixed to the output end of the third rotating stage 1-2-3 through the clamping rod through hole 1-1-5-2. The other end has piezoelectric ceramic assembly grooves 1-1-5-1 on both sides, and a clamping piezoelectric ceramic 1-1-4 is fixedly installed on it and limited by the piezoelectric ceramic assembly surface 1-1-5-3 on the clamping rod.

[0048] A clamping plate 1-1-3 is fixedly connected to the movable end of the piezoelectric ceramic 1-1-4; the structure of the clamping plate is as follows: Figure 4 As shown, it includes a clamping plate groove 1-1-3-1 and a clamping plate main board 1-1-3-2; two clamping piezoelectric ceramics 1-1-4 are glued to each other by means of adhesive bonding, with one end attached to the piezoelectric ceramic assembly groove 1-1-5-1 and the other end attached to the clamping plate main board 1-1-3-2; then two carbon fiber rods 1-1-8 are fixed in the clamping plate groove 1-1-3-1 of the two clamping plates 1-1-3 by means of adhesive bonding; the two carbon fiber rods are arranged facing each other and there is a distance between their ends. Then, clamp 1-1-1 is fixed to slider 1-1-2 by screwing screws into clamp fixing holes 1-1-2-5. Slider is nested into two carbon fiber rods 1-1-8. The upper plate 1-1-2-2 and slider boss 1-1-2-4 limit the contact between carbon fiber rods 1-1-8. Long screws are passed through spring 1-1-6 and slider through hole 1-1-2-1 and screwed into slider threaded hole 1-1-2-3. The friction between slider 1-1-2 and carbon fiber rod 1-1-8 is adjusted by the tightness of the long screws. At this point, clamping drive unit 1-1 is assembled.

[0049] The clamping drive unit is driven by a periodic excitation signal. One working cycle of the periodic excitation signal includes a stationary phase, a sticking phase, and a sliding phase. During the stationary phase, the excitation signal is zero, and the clamping drive unit is stationary.

[0050] During the adhesion stage, the input voltage of the excitation signal changes slowly. During this stage, the clamping piezoelectric ceramic elongates or retracts with the slow change of voltage. The combination of the clamping plate and the carbon fiber rod moves slowly. Due to the friction between the combination and the slider under the pre-tightening force, and because of the slow movement during this stage, the friction is static friction. Under the action of static friction, the combination drives the two sliders to move a distance d1 respectively.

[0051] During the sliding phase, the input voltage of the excitation signal changes rapidly. During this phase, the clamping piezoelectric ceramic rapidly elongates or contracts with the rapid change of voltage, and the assembly also moves rapidly. Due to the rapid movement during this phase, relative motion will occur between the assembly and the slider. The friction force is dynamic friction. Under the action of dynamic friction, the two sliders will each have a small retraction displacement Δd, and the moving distance is reduced to d2.

[0052] The voltage changes in the sticking and sliding stages are opposite in direction, so the piezoelectric ceramic and the slider move in opposite directions in the two stages; within one cycle, each slider gains a net displacement, the net displacement d2 = d1 - Δd, and the distance the two parts of the clamp of the clamping drive unit move is 2 × d2.

[0053] like Figure 9 As shown, the bases 1-2-7 of both the second rotary table 1-2-2 and the third rotary table 1-2-3 include a base extension plate 1-2-7-2, and the base extension plate 1-2-7-2 is provided with a base extension plate connecting through hole 1-2-7-1 for connection and installation. The length direction of the base extension plate passes through the rotation center of the rotary table to which it is located.

[0054] like Figure 1 and Figure 6 As shown, the first rotary table 1-2-1 has a vertical axis, and its output end rotates around the axis. The base extension plate of the second rotary table is installed at the center of the output end of the first rotary table, and the length direction of the base extension plate is collinear with the axis of the first rotary table; the axis of the second rotary table is horizontal, and the base extension plate of the third rotary table is installed at the output end of the second rotary table and is perpendicular to the axis of the second rotary table; the axis of the third rotary table 1-2-3 is horizontal, and one end of the clamping rod 1-1-5 is fixed on the third rotary table 1-2-3, with the length direction of the clamping rod perpendicular to the axis of the third rotary table.

[0055] In this embodiment, the first rotary stage 1-2-1, the second rotary stage 1-2-2, and the third rotary stage 1-2-3 are all driven by a rotary piezoelectric drive unit with identical structure. The second rotary stage 1-2-2 and the third rotary stage 1-2-3 are structurally identical, differing only in the weight of the counterweight 1-2-6. The counterweight of the second rotary stage is heavier than that of the third rotary stage, and its weight is adjusted according to the weight of the object being held. Ideally, the weight of the counterweight should be chosen so that the second rotary stage 1-2-2 and the third rotary stage 1-2-3 remain stationary (i.e., do not rotate) when no excitation signal is input. The first rotary stage does not require a counterweight, and its base structure does not require a base extension plate; its other structures are the same as those of the second rotary stage 1-2-2 and the third rotary stage 1-2-3. The output end of each of the three rotary stages is referred to as an output end cover.

[0056] like Figure 10 As shown, the output end cover can be customized with connection holes 1-2-4-2, connection grooves 1-2-4-1, etc., to facilitate the installation and fixation of the next stage mechanism. The output form of each rotary table is the rotation of the output end cover around its axis. Figure 10 The diagram shows the output end cover plates of the second rotary table 1-2-2 and the third rotary table 1-2-3. Two connecting grooves 1-2-4-1 are provided on the output end cover plates in the same diameter direction, which are used to install the lower-level mechanism and the counterweight respectively. The connecting hole 1-2-4-2 in the connecting groove 1-2-4-1 is used to fix the lower-level mechanism and the counterweight (which can be fixed with screws). A partition 1-2-4-3 is provided between the two connecting grooves 1-2-4-1 so that they are not connected.

[0057] The rotary piezoelectric drive unit is introduced using the first rotary stage 1-2-1 as an example. The structure and working principle of the rotary piezoelectric drive unit are exactly the same for each stage of the rotary stage. The rotary piezoelectric drive unit mainly includes a collar 1-2-1-2, a friction plate 1-2-1-3, a preload magnet 1-2-1-4, a piezoelectric ceramic 1-2-1-7, and a drive magnet 1-2-1-8. The fixed end of the piezoelectric ceramic 1-2-1-7 and the preload magnet 1-2-1-4 are both fixed on the mounting base (i.e., base 1-2-1-1) of the rotary piezoelectric drive unit. The movable end of the piezoelectric ceramic is driven by an external excitation signal to extend or retract along a preset motion direction. The preload magnet 1-2-1-4 is positioned opposite the movable end of the piezoelectric ceramic, with a distance between them. The drive magnet 1-2-1-8 and the friction plate 1-2-1-3 are bonded together. The assembly is positioned between the pre-tightening magnet 1-2-1-4 and the movable end of the piezoelectric ceramic. The collar 1-2-1-2 is made of ferromagnetic material. The driving magnet 1-2-1-8 and the collar 1-2-1-2 are attracted by magnetic force, and the friction plate 1-2-1-3 is fixed between them. Both the driving magnet 1-2-1-8 and the pre-tightening magnet 1-2-1-4 are single-stage magnetized, and their internal magnetic fields are in opposite directions. When the piezoelectric ceramic 1-2-1-7 is driven by an excitation signal, under the action of the repulsive force between the driving magnet and the pre-tightening magnet and the attraction force between the driving magnet and the collar, the driving magnet can only adhere to the movable end of the piezoelectric ceramic and drive the shaft to rotate around its axis.

[0058] In this embodiment, the collar 1-2-1-2 can be made of ferromagnetic materials such as bearing steel, and the friction plate 1-2-1-3 can be made of non-ferromagnetic wear-resistant materials such as chromium and manganese. The millimeter-sized friction plate 1-2-1-3 provides sufficient service life for the rotary table I 1-2-1.

[0059] The rotary piezoelectric drive unit of the present invention is driven by a periodic excitation signal. One working cycle of the periodic excitation signal includes a stationary phase, a sticking phase, and a sliding phase. During the stationary phase, the excitation signal is zero, and the clamping drive unit is stationary.

[0060] During the adhesion stage, the input voltage of the excitation signal changes slowly. During this stage, the piezoelectric ceramic elongates or retracts with the slow change in voltage, driving the combination of magnet and friction plate to move slowly. Due to the friction between the combination and the collar under the preload, and because of the slow movement during this stage, the friction is static friction. Under the action of static friction, the combination drives the collar to rotate by an angle θ1.

[0061] During the sliding phase, the input voltage of the excitation signal changes rapidly. During this phase, the piezoelectric ceramic elongates or contracts rapidly with the rapid change of voltage, and the assembly also moves rapidly. Due to the rapid movement during this phase, relative movement will occur between the assembly and the collar. The friction force is dynamic friction. Under the action of dynamic friction, the collar retracts by a certain angle Δθ, reducing the rotation angle from θ1 to θ2.

[0062] The voltage changes in the sticking and sliding stages are opposite in direction, so the piezoelectric ceramic moves in opposite directions in the two stages, and the corresponding collar rotates in opposite directions in the two stages; within one cycle, the collar obtains a net rotation angle θ2=θ1-Δθ.

[0063] The assembly process will now be described using the first rotary table 1-2-1 as an example. Figure 7 The diagram shows the structure of the first rotary table, which includes a base 1-2-1-1, a collar 1-2-1-2, a friction plate 1-2-1-3, a pre-tightening magnet 1-2-1-4, a magnet clamping cover 1-2-1-5, a sealing cover 1-2-1-6, a piezoelectric ceramic 1-2-1-7, a driving magnet 1-2-1-8, an inner ring clamping cover 1-2-1-9, an outer ring connecting cover 1-2-1-10, and a connecting cover 1-2-1-11. Figure 8 The diagram illustrates the base structure of the first rotary table, which mainly includes a bearing limiting platform 1-2-1-1-1, a shoulder 1-2-1-1-2, a threaded hole 1-2-1-1-3, a pre-tightening magnet mounting platform 1-2-1-1-4, a drive magnet mounting platform 1-2-1-1-5, a cable routing hole 1-2-1-1-6, a ceramic mounting groove 1-2-1-1-7, and a collar fixing threaded hole 1-2-1-1-8.

[0064] During assembly, firstly, the piezoelectric ceramic 1-2-1-7 is glued to the ceramic mounting groove 1-2-1-1-7, and its wires are discharged through the cable routing hole 1-2-1-1-6; then, the inner ring of the collar 1-2-1-2 is embedded into the bearing limiting platform 1-2-1-1-1, and the shoulder 1-2-1-1-2 limits its movement; then, the inner ring clamping cap is fitted onto the inner ring of the collar 1-2-1-2, with the inner ring clamping cap 1-2-1-9 providing limiting; the collar 1-2-1-2 is fixed to the base 1-2-1-1 by screws passing through the countersunk hole of the inner ring clamping cap and screwing into the threaded hole; finally, the outer ring connecting cap 1-2-1-1 is glued to the base. 0 is fixed on the outer ring of the collar 1-2-1-2, and the outer ring connecting cover 1-2-1-10 can rotate relative to the base 1-2-1-1; then, the pre-tightening magnet 1-2-1-4 is embedded into the pre-tightening magnet mounting platform 1-2-1-1-4, and the pre-tightening magnet 1-2-1-4 is fixed by passing a screw through the countersunk hole 1-2-1-5-2 of the magnet clamping cover and screwing it into the corresponding threaded hole 1-2-1-1-3. The friction plate 1-2-1-3 and the driving magnet 1-2-1-8 are glued together, and then nested together into the groove between the pre-tightening magnet 1-2-1-4 and the piezoelectric ceramic 1-2-1-7. Both the drive magnet 1-2-1-8 and the ferromagnetic magnet 1-2-1-8 are unipolar magnets, and they repel each other, ensuring that the drive magnet 1-2-1-8 is tightly attached to the piezoelectric ceramic 1-2-1-7 after assembly. The pre-tightening magnet 1-2-1-4 is slightly higher than the drive magnet 1-2-1-8 in the axial height direction, allowing the drive magnet 1-2-1-8 to be tightly attached to the drive magnet mounting platform 1-2-1-1-5 after being driven by the piezoelectric ceramic 1-2-1-7. The collar 1-2-1-2 is made of ferromagnetic material, and under the action of magnetic attraction, the connector composed of the friction plate 1-2-1-3 and the drive magnet 1-2-1-8 can still maintain its connection even after the friction plate 1-2-1-3 has worn to a certain height. To maintain a stable adsorption force and friction with the collar 1-2-1-2, wear self-adsorption is achieved. The friction plate 1-2-1-3 is made of wear-resistant material, providing sufficient service life for the rotary table. Then, screws are passed through the countersunk hole of the cover 1-2-1-6 and screwed into the corresponding threaded hole 1-2-1-1-3 to encapsulate the piezoelectric ceramic 1-2-1-7 and the driving magnet 1-2-1-8. The cover boss can be used for positioning during assembly. Then, the connecting cover 1-2-1-11 is fixed to the outer ring connecting 1-2-1-10 by screws passing through the countersunk hole of the connecting cover and screwing into the threaded hole of the outer ring connecting cover.

[0065] When the microrobot of this invention is working, the clamping drive unit, as well as the rotational piezoelectric drive units of the first, second, and third rotary stages, are driven by independent excitation signals. The excitation signal can be a periodic sawtooth wave signal. The signal waveform of a single cycle includes a sticking phase with linear voltage changes and a sliding phase with linear voltage changes. During the sticking phase, the absolute value of the slope of the voltage change curve is small, and there is no relative movement between the assembly and the output platform (the slider or collar in this invention). During the sliding phase, the absolute value of the slope of the voltage change curve is large, and there is relative sliding between the assembly and the output platform.

[0066] like Figure 11 As shown, in this embodiment, the bonding section is selected as the voltage rise stage, and the sliding stage is selected as the voltage fall stage; in the clamping drive unit, the slider moves a net displacement d2 in the elongation direction of the piezoelectric ceramic in each cycle, increasing the distance between the clamping arms of the clamp, thus realizing the release action of the clamp. Figure 11 Under the excitation signal shown, in each cycle, the rotating piezoelectric drive unit generates a net rotation angle θ2 in the clockwise direction. It should be noted that by changing the waveform of the excitation signal (e.g., selecting the voltage drop phase for the bonding segment and the voltage rise phase for the sliding phase), the output platform can generate a net displacement or net rotation angle in the direction of piezoelectric ceramic retraction. This invention effectively reduces the wear effect of the friction pair by introducing a magnetic coupling wear adaptive compensation mechanism. After the friction plate or collar wears, under the combined forces of the repulsive force between the driving magnet and the pre-tightening magnet, and the attraction force between the driving magnet and the collar, the friction plate always maintains stable contact with the collar and maintains a relatively stable friction force; achieving cross-scale precise motion: by adopting an optimized piezoelectric drive scheme, the robot can achieve high-precision motion in the micrometer and nanometer range, and can also maintain stable stepping and positioning in the millimeter range through high-frequency periodic excitation, achieving cross-scale adaptability.

[0067] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A multi-scale, multi-degree-of-freedom micro-operation robot, characterized in that, The system includes a clamping drive unit and a three-degree-of-freedom rotary drive unit. The three-degree-of-freedom rotary drive unit comprises a first rotary table, a second rotary table, and a third rotary table, each with a base. The first rotary table is horizontally arranged on its base, and its output end is fixedly connected to the base of the second rotary table, driving the second rotary table and its base to rotate in the vertical direction. The output end of the second rotary table is connected to the base of the third rotary table, driving the third rotary table and its base to rotate in the vertical plane. The output end of the third rotary table is connected to the clamping drive unit, driving the clamping drive unit to rotate in the vertical plane. The first, second, and third rotary tables are driven by rotary piezoelectric drive units with identical structures. The rotary piezoelectric drive unit includes a collar, a friction plate, a preload magnet, a piezoelectric ceramic, and a drive magnet; The fixed end of the piezoelectric ceramic and the pre-tightening magnet are both fixed on the mounting base of the rotary piezoelectric drive unit. The movable end of the piezoelectric ceramic is driven by an external excitation signal to extend or retract along a preset motion direction. The pre-tightening magnet is positioned opposite the movable end of the piezoelectric ceramic, with a distance between them. The drive magnet and the friction plate are bonded together, and the combined body is positioned between the pre-tightening magnet and the movable end of the piezoelectric ceramic. The collar is made of ferromagnetic material, and the drive magnet and the collar are attracted by magnetic force, fixing the friction plate between them. Both the drive magnet and the pre-tightening magnet are single-stage magnetized, and their internal magnetic fields are in opposite directions. When the piezoelectric ceramic is driven by an excitation signal, under the action of the repulsive force between the drive magnet and the pre-tightening magnet and the attraction force between the drive magnet and the collar, the drive magnet can only adhere to the movable end of the piezoelectric ceramic and drive the shaft to rotate around its axis. The clamping drive unit includes a clamp, a slider, a clamping plate, a clamping piezoelectric ceramic, a clamping rod, and a carbon fiber rod. One end of the clamping rod is fixed to the output end of the third rotary table. A clamping piezoelectric ceramic is fixedly installed on both sides of the other end. A clamping plate is fixedly connected to the movable end of the clamping piezoelectric ceramic. Two carbon fiber rods are fixed to the inner sides of the two clamping plates respectively. The two carbon fiber rods are arranged facing each other and there is a distance between their ends. Two sliders are respectively sleeved on the two carbon fiber rods and fixed to the carbon fiber rods under the action of pre-tightening force. The two parts of the clamp are respectively connected to the two sliders.

2. The multi-scale, multi-degree-of-freedom micro-operation robot according to claim 1, characterized in that, The clamping drive unit further includes a spring and a clamping preload screw; the slider includes an upper slider plate and a lower slider plate connected to each other, the upper slider plate and the lower slider plate are installed in parallel, forming a carbon fiber rod mounting groove between them, a slider boss is provided on the wall of the lower slider plate side in the carbon fiber rod mounting groove, the upper slider plate is provided with a slider through hole in the thickness direction, and the lower slider plate is provided with a slider threaded hole at the position directly opposite the slider through hole; after the carbon fiber rod is inserted into the carbon fiber rod mounting groove, the clamping preload screw is passed through the spring and the slider through hole and screwed into the slider threaded hole, and the friction between the slider and the carbon fiber rod is adjusted by the tightening degree of the clamping preload screw.

3. The multi-scale, multi-degree-of-freedom micro-operation robot according to claim 2, characterized in that, The clamping drive unit is driven by a periodic excitation signal. One working cycle of the periodic excitation signal includes a stationary phase, a sticking phase, and a sliding phase. During the stationary phase, the excitation signal is zero, and the clamping drive unit is stationary. During the adhesion stage, the input voltage of the excitation signal changes slowly. During this stage, the clamping piezoelectric ceramic elongates or retracts with the slow voltage change, and the assembly consisting of the clamping plate and carbon fiber rod moves slowly. Due to the friction between the assembly and the slider under the preload, and because of the slow movement during this stage, the friction is static friction. Under the action of static friction, the assembly drives the two sliders to move a distance respectively. d 1; During the sliding phase, the input voltage of the excitation signal changes rapidly. During this phase, the clamping piezoelectric ceramic rapidly elongates or contracts with the rapid voltage change, and the assembly also moves rapidly. Due to this rapid movement, relative motion occurs between the assembly and the slider, resulting in kinetic friction. Under the action of kinetic friction, both sliders exhibit a small retraction displacement Δ. d The slider movement distance is reduced to d 2; The voltage changes in the sticking and sliding stages are in opposite directions, therefore the piezoelectric ceramic and the slider move in opposite directions in the two stages; within one cycle, each slider gains a net displacement, the net displacement amount... d 2 =d 1-Δ d The two parts of the clamp holding the drive unit move a distance of 2. c×d 2.

4. The multi-scale, multi-degree-of-freedom micro-operation robot according to claim 1, characterized in that, The first rotary table has a vertical axis and its output end rotates around the axis. The bases of the second and third rotary tables each include a base extension plate, the length of which passes through the rotation center of the rotary table. The base extension plate of the second rotary table is installed at the output end of the first rotary table, and the length of the base extension plate is collinear with the axis of the first rotary table. The axis of the second rotary table is horizontal. The base extension plate of the third rotary table is installed at the output end of the second rotary table and is perpendicular to the axis of the second rotary table. The axis of the third rotary table is horizontal. One end of the clamping rod is fixed on the third rotary table, and the length of the clamping rod is perpendicular to the axis of the third rotary table.

5. The multi-scale, multi-degree-of-freedom micro-operation robot according to claim 4, characterized in that, The collar includes an inner ring and an outer ring that can rotate relative to each other. The inner ring of the collar is fixed on the base of the corresponding rotary table. The combination of the friction plate and the driving magnet is connected to the outer ring of the collar. The output end of the corresponding rotary table is fixedly connected to the outer ring of the collar. The axial direction of the collar is the axial direction of the corresponding rotary table.

6. The multi-scale, multi-degree-of-freedom micro-operation robot according to claim 4, characterized in that, The rotary piezoelectric drive unit is driven by a periodic excitation signal. One working cycle of the periodic excitation signal includes a stationary phase, a sticking phase, and a sliding phase. During the stationary phase, the excitation signal is zero, and the clamping drive unit is stationary. During the adhesion stage, the input voltage of the excitation signal changes slowly. During this stage, the piezoelectric ceramic elongates or retracts with the slow change in voltage, driving the combination of magnet and friction plate to move slowly. Due to the friction between the combination and the collar under the preload, and because of the slow movement during this stage, the friction is static friction. Under the action of static friction, the combination drives the collar to rotate by an angle θ1. During the sliding phase, the input voltage of the excitation signal changes rapidly. During this phase, the piezoelectric ceramic elongates or contracts rapidly with the rapid change of voltage, and the assembly also moves rapidly. Due to the rapid movement during this phase, relative movement will occur between the assembly and the collar. The friction force is dynamic friction. Under the action of dynamic friction, the collar retracts by a certain angle Δθ, reducing the rotation angle from θ1 to θ2. The voltage changes in the sticking and sliding stages are in opposite directions, therefore the piezoelectric ceramic moves in opposite directions in the two stages, and correspondingly the collar rotates in opposite directions in the two stages; within one cycle, the collar acquires a net rotation angle θ2. = θ1-Δθ.

7. The multi-scale, multi-degree-of-freedom micro-operation robot according to claim 4, characterized in that, The output end of the second rotary table is also provided with a counterweight, which is installed on the extension line of the base extension plate of the third rotary table to balance the weight of the third rotary table. The output end of the third rotary table is also equipped with a counterweight, which is installed on the extension line of the clamping rod to balance the weight of the clamping drive unit.

8. The multi-scale, multi-degree-of-freedom micro-operation robot according to claim 1, characterized in that, The clamping drive unit, as well as the rotary piezoelectric drive units of the first rotary table, the second rotary table, and the third rotary table, are driven by independent excitation signals.

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