Long-life cross-scale multi-degree-of-freedom micro-motion robot

Abstract

The invention discloses a long-life cross-scale multi-degree-of-freedom micro robot which comprises a clamping driving unit and a three-degree-of-freedom rotating driving unit, the three-degree-of-freedom rotating driving unit comprises three stages of rotating tables, and the rotating tables are driven by rotating piezoelectric driving units of the same structure; the rotary piezoelectric driving unit and the clamping driving unit are driven by adopting independent periodic excitation signals, and net displacement or net rotation angles are generated in a working period. In order to solve the problem that the service life of a driving device is limited due to frictional wear in piezoelectric cross-scale friction transmission, a magnetic coupling wear self-adaptive compensation mechanism is introduced, and after a friction plate or a shaft ring is worn, the friction plate or the shaft ring is subjected to self-adaptive compensation under multiple acting forces of repulsive force of a driving magnet and a pre-tightening magnet and adsorption force of the driving magnet and the shaft ring. The friction plate is in stable contact with the shaft ring all the time, and stable friction force is maintained; and cross-scale accurate movement and long-time service are realized.

Description

Technical Field

[0001] The present invention belongs to the field of micro-robots, and in particular relates to a long-life, cross-scale, multi-degree-of-freedom micro-robot. Background Art

[0002] Microrobots are widely used in precision manipulation, biomedical engineering, and micro-nano manufacturing. Piezoelectric-driven microrobots have attracted widespread attention due to their fast response speed, high positioning accuracy, and lack of magnetic interference. Currently, mainstream piezoelectric-driven microrobots utilize the inverse piezoelectric effect, using periodic electrical signals to achieve micron- and even nanometer-scale stepping motion. These robots typically incorporate linear motion mechanisms, rotational motion mechanisms, and multi-degree-of-freedom compound motion mechanisms to meet the needs of diverse application scenarios.

[0003] Although existing piezoelectric-driven microrobots have excellent performance in terms of precision and dynamic performance, they still have the following technical bottlenecks:

[0004] Poor cross-scale adaptability: Existing micro-robots are usually optimized for specific scales, and their motion performance is difficult to balance when applied across scales (e.g., from micron-scale manipulation to millimeter-scale movement);

[0005] Limited lifespan: During long-term operation, the drive mechanisms (such as friction pairs) of traditional cross-scale micro-robots are susceptible to wear, resulting in performance degradation and reduced reliability and lifespan of the equipment.

[0006] Limited degrees of freedom: Existing designs are mostly limited to a single or a few degrees of freedom, making it difficult to meet complex operational requirements and limiting their applicability in high-precision manipulation.

[0007] Insufficient wear compensation capability: Due to the accumulation of friction and wear, the existing system often leads to friction drive failure after long-term operation, and lacks an effective adaptive compensation mechanism; CN202411607812.2 discloses a durable three-axis drive mechanism for a minimally invasive cell puncture instrument, which achieves friction and wear adaptation through a cascaded magnet configuration, but requires three cascaded magnets to be coupled, and the piezoelectric ceramics will be subjected to additional tensile stress and shear stress when driven. Excessive amplitude will cause damage to the piezoelectric ceramics, making it necessary to use piezoelectric ceramics with a protective shell, which increases the volume and complexity of the system. Summary of the Invention

[0008] To solve the problems in the prior art, the present invention proposes a long-life, cross-scale, multi-degree-of-freedom micro-robot. The technical solution is as follows:

[0009] A long-life, cross-scale, multi-degree-of-freedom micro-manipulator robot comprises a clamping drive unit and a three-degree-of-freedom rotation drive unit, wherein the three-degree-of-freedom rotation drive unit comprises a first rotating platform, a second rotating platform, and a third rotating platform, each of which has a base; the first rotating platform is horizontally arranged on its base, and its output end is fixedly connected to the base of the second rotating platform, driving the second rotating platform and its base to rotate in a vertical direction; the output end of the second rotating platform is connected to the base of the third rotating platform, driving the third rotating platform and its base to rotate in a vertical plane; the output end of the third rotating platform is connected to the clamping drive unit, driving the clamping drive unit to rotate in a vertical plane; the first, second, and third rotating platforms are driven by rotary piezoelectric drive units with the same structure;

[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 rotating table; a clamping piezoelectric ceramic is fixed on both sides of the other end, and the movable end of the clamping piezoelectric ceramic is fixedly connected to a clamping plate; two carbon fiber rods are respectively fixed on the inner sides of the two clamping plates, and the two carbon fiber rods are arranged opposite to each other with a distance between the ends, and the 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, and 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 also includes a spring and a clamping pre-tightening screw; the slider includes a slider upper plate and a slider lower plate that are connected to each other, the slider upper plate and the slider lower plate are installed in parallel, and a carbon fiber rod mounting groove is formed therebetween, and a slider boss is provided on the wall surface on the slider lower plate side in the carbon fiber rod mounting groove, and the slider upper plate is provided with a slider through hole that passes through the slider upper plate in the thickness direction, and a slider threaded hole is provided on the slider lower plate at a position opposite to the slider through hole; after the carbon fiber rod is installed in the carbon fiber rod mounting groove, a clamping pre-tightening screw is used to pass 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 pre-tightening 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 sticking stage, the input voltage of the excitation signal changes slowly. In this stage, the clamped piezoelectric ceramics extend or retract with the slow change of voltage, and 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 action of the preload force, and the slow movement in 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 stage, the input voltage of the excitation signal changes rapidly. In this stage, the clamped piezoelectric ceramics extend or contract rapidly with the rapid change of voltage, and the combination also moves rapidly. Due to the rapid movement, relative motion will occur between the combination 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 change directions in the sticking stage and the sliding stage are opposite, so the clamping piezoelectric ceramic and the slider move in opposite directions in the two stages; within one cycle, each slider obtains a net displacement, the net displacement d2 = d1 - Δd, and the moving distance of the two parts of the clamping drive unit is 2*d2.

[0016] According to a specific embodiment of the present invention, the axis direction of the first rotating platform is vertical, and its output end rotates around the axis direction; the bases of the second rotating platform and the third rotating platform each include a base extension plate, the length direction of the base extension plate passes through the rotation center of the rotating platform on which it is located; the base extension plate of the second rotating platform is installed at the output end of the first rotating platform, and the length direction of the base extension plate is collinear with the axis direction of the first rotating platform;

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

[0018] According to a specific embodiment of the present invention, the rotary piezoelectric drive unit includes a shaft ring, 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 rotating piezoelectric drive unit, and the movable end of the piezoelectric ceramic is driven by an external excitation signal to extend or retract along a preset direction of movement; the pre-tightening magnet is arranged opposite to the movable end of the piezoelectric ceramic, and there is a distance between the two; the driving magnet and the friction plate are bonded, and the combination of the two is arranged between the pre-tightening magnet and the movable end of the piezoelectric ceramic, and the shaft ring is made of ferromagnetic material, and the driving magnet and the shaft ring are attracted by magnetic force and fix the friction plate between the two; the driving magnet and the pre-tightening magnet are both single-pole magnetized, and the 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 driving magnet and the pre-tightening magnet and the adsorption force between the driving magnet and the shaft ring, the driving magnet can only always fit 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 shaft ring includes an inner ring and an outer ring that can rotate relative to each other, the inner ring of the shaft ring is fixed on the base of the corresponding turntable, the combination of the friction plate and the driving magnet is connected to the outer ring of the shaft ring, and the output end of the corresponding turntable is fixedly connected to the outer ring of the shaft ring; the axial direction of the shaft ring is the axial direction of the corresponding turntable.

[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 sticking stage, the input voltage of the excitation signal changes slowly. In this stage, the piezoelectric ceramic extends or retracts with the slow change of voltage, driving the combination of the magnet and the friction plate to move slowly. Due to the friction between the combination and the collar under the action of the preload force, and due to the slow movement in 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 stage, the input voltage of the excitation signal changes rapidly. In this stage, the piezoelectric ceramics extend or contract rapidly with the rapid change of voltage, and the combination also moves rapidly. Due to the rapid movement, relative motion will occur between the combination and the collar. 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 stage and the sliding stage are in opposite directions, so the piezoelectric ceramic moves in opposite directions in the two stages, and the corresponding shaft ring rotates in opposite directions in the two stages; within one cycle, the shaft ring obtains a net rotation angle Δθ = θ1-θ2.

[0025] According to a specific embodiment of the present invention, a counterweight block is further provided at the output end of the second rotating platform, and the counterweight block is installed on the extension line of the base extension plate of the third rotating platform to balance the weight of the third rotating platform;

[0026] The output end of the third rotating platform is also provided with a counterweight block, which is installed on the extension line of the clamping rod and is used to balance the weight of the clamping drive unit.

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

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

[0029] The present invention provides a long-life, cross-scale, multi-degree-of-freedom micro-manipulator with significantly improved service life. By introducing a magnetic coupling wear adaptive compensation mechanism, the present invention effectively reduces the wear effects of the friction pair. After wear of the friction plate or collar, the friction plate maintains stable contact with the collar and relatively stable friction under the combined forces of repulsion between the drive magnet and the preload magnet, and attraction between the drive magnet and the collar. Cross-scale precision motion is achieved by employing an optimized piezoelectric drive scheme, enabling the robot to achieve high-precision motion within the micron and nanometer ranges while maintaining stable stepping and positioning within the millimeter range through high-frequency periodic excitation, achieving cross-scale adaptability. Increased degrees of freedom of motion are achieved by designing a multi-degree-of-freedom drive structure that supports more complex motion modes, meeting the requirements of high-precision micro-manipulation and broadening its application scenarios. The robot can be widely used in fields such as biological cell manipulation, micro-nano manufacturing, and precision assembly, meeting the requirements of high precision and long-term stable operation. This invention provides a new solution for the development of high-precision micro-manipulator technology, enhancing the robot's capabilities in terms of long life, cross-scale adaptability, and high-degree-of-freedom control. It has important engineering application value and industrialization prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The overall schematic diagram of a long-life, cross-scale, multi-DOF micro-robot;

[0031] Figure 2 Schematic diagram of the clamping drive unit;

[0032] Figure 3 Schematic diagram of the slider structure;

[0033] Figure 4 Schematic diagram of the clamping plate structure;

[0034] Figure 5 Schematic diagram of the clamping rod structure;

[0035] Figure 6 Schematic diagram of the structure of a three-degree-of-freedom rotation drive unit;

[0036] Figure 7 Schematic diagram of the structure of the first rotating platform;

[0037] Figure 8 Schematic diagram of the base structure of the first rotating platform;

[0038] Figure 9 Schematic diagram of the base structure of the second rotating platform;

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

[0040] Figure 11This is the working principle diagram of the long-life, cross-scale, multi-degree-of-freedom micro-robot. DETAILED DESCRIPTION

[0041] The present invention will be further described and illustrated below in conjunction with specific embodiments. The embodiments are merely illustrative of the present disclosure and do not limit its scope. The technical features of the various embodiments of the present invention may be combined accordingly, provided that there is no conflict between them.

[0042] The overall schematic diagram of a long-life, cross-scale, multi-degree-of-freedom micro-robot designed by the present invention is as follows: 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-robot. In a specific embodiment of the present invention, Figure 6 As shown, the three-degree-of-freedom rotation drive unit includes a first rotation stage 1-2-1, a second rotation stage 1-2-2 and a third rotation stage 1-2-3, and all three rotation stages have a base; the first rotation stage 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 rotation stage, driving the second rotation stage and its base to rotate in a vertical direction; the output end of the second rotation stage is connected to the base of the third rotation stage, driving the third rotation stage and its base to rotate in a vertical plane; the output end of the third rotation stage is connected to the clamping drive unit 1-1, driving the clamping drive unit to rotate in a vertical plane; the first rotation stage, the second rotation stage and the third rotation stage are driven by a rotation piezoelectric drive unit with the same structure.

[0044] The clamping drive unit 1-1 is the action end of the multi-degree-of-freedom micro-robot. Figures 2 to 5 As shown, in a 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 pre-tightening screw 1-1-7, and a carbon fiber rod 1-1-8.

[0045] See also Figure 2 The clamp 1-1-1 is used to clamp an object and includes two clamping arms with identical structures and symmetrical arrangement. One end of the two clamping arms is fixed on two sliders 1-1-2 respectively, and the other ends of the two clamping arms are suspended in the air 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 an embodiment of the present invention, the clamping arm is configured to be thin-sheet-shaped, and its material can be selected according to actual needs.

[0046] like Figure 3As shown, the slider includes a slider upper plate 1-1-2-2 and a slider lower plate connected to each other by a slider hinge 1-1-2-6. The slider upper plate 1-1-2-2 and the slider lower plate are installed in parallel, and a carbon fiber rod installation groove is formed between the two. The wall surface of the slider lower plate side in the carbon fiber rod installation groove is provided with a slider boss 1-1-2-4. The slider upper plate 1-1-2-2 is provided with a slider through hole 1-1-2-1 that passes through the slider upper plate in the thickness direction. The slider lower plate is provided with a slider threaded hole 1-1-2-1 at a position opposite to the slider through hole. -1-2-3; After the carbon fiber rod 1-1-8 is installed in the carbon fiber rod installation groove, the clamping pre-tightening screw 1-1-7 is used to pass 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 tightening degree of the clamping pre-tightening screw. The setting of the slider hinge 1-1-2-6 makes it easy to adjust the distance between the slider upper plate 1-1-2-2 and the slider lower plate to achieve the adjustment of the pre-tightening force.

[0047] like Figure 5 As shown, the clamping rod is a long strip of rod with a certain length, one end of which is fixed to the output end of the third rotating table 1-2-3 through the clamping rod through hole 1-1-5-2; the other end is provided with piezoelectric ceramic assembly grooves 1-1-5-1 on both sides of the end, on which a clamping piezoelectric ceramic 1-1-4 is fixedly provided, and is limited by the piezoelectric ceramic assembly surface 1-1-5-3 on the clamping rod.

[0048] The movable end of the clamping piezoelectric ceramic 1-1-4 is fixedly connected to a clamping plate 1-1-3; 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; one end of the two clamping piezoelectric ceramics 1-1-4 is glued to the piezoelectric ceramic assembly groove 1-1-5-1, and the other end is glued to the clamping plate main board 1-1-3-2 by gluing; then the two carbon fiber rods 1-1-8 are fixed in the clamping plate grooves 1-1-3-1 of the two clamping plates 1-1-3 by gluing; the two carbon fiber rods are arranged opposite to each other, and there is a distance between the ends. Then, the clamp 1-1-1 is screwed into the clamp fixing hole 1-1-2-5 to fix it on the slider 1-1-2, and the slider is nested on the two carbon fiber rods 1-1-8, wherein the slider upper plate 1-1-2-2 and the slider boss 1-1-2-4 limit the contact with the carbon fiber rod 1-1-8, and a long screw is used to pass 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, and the friction between the slider 1-1-2 and the carbon fiber rod 1-1-8 is adjusted by the tightening degree of the long screw. At this point, the clamping drive unit 1-1 is assembled.

[0049] 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;

[0050] During the sticking stage, the input voltage of the excitation signal changes slowly. In this stage, the clamped piezoelectric ceramics extend or retract with the slow change of voltage, and 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 action of the preload force, and the slow movement in 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 stage, the input voltage of the excitation signal changes rapidly. In this stage, the clamped piezoelectric ceramics extend or contract rapidly with the rapid change of voltage, and the combination also moves rapidly. Due to the rapid movement, relative motion will occur between the combination 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 change directions in the sticking stage and the sliding stage are opposite, so the clamping piezoelectric ceramic and the slider move in opposite directions in the two stages; within one cycle, each slider obtains a net displacement, the net displacement d2 = d1 - Δd, and the moving distance of the two parts of the clamping drive unit is 2*d2.

[0053] like Figure 9 As shown, the base 1-2-7 of the second rotating platform 1-2-2 and the third rotating platform 1-2-3 each includes 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 rotating platform on which it is located.

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

[0055] The first rotating platform 1-2-1, the second rotating platform 1-2-2 and the third rotating platform 1-2-3 of the present embodiment are all driven by the rotating piezoelectric drive unit with the same structure. Wherein, the second rotating platform 1-2-2 and the third rotating platform 1-2-3 are identical in structure, and the difference between the two is that the weight of the counterweight 1-2-6 is different. Wherein, the weight of the counterweight of the second rotating platform is greater than the counterweight of the third rotating platform, and the weight of the counterweight also needs to be adjusted accordingly according to the weight of the object being clamped. Ideally, the weight selection of the counterweight should make the second rotating platform 1-2-2 and the third rotating platform 1-2-3 remain stationary (i.e., do not rotate) when no excitation signal is input. The first rotating platform does not need a counterweight, and its base structure does not need a base extension plate. Other structures are the same as the second rotating platform 1-2-2 and the third rotating platform 1-2-3. The output ends of the three rotating platforms are all called output end cover plates.

[0056] like Figure 10 As shown, the output end cover plate can be customized to have connection holes 1-2-4-2, connection grooves 1-2-4-1 and other structures as needed to facilitate the installation and fixation of the next level mechanism. The output form of each level of the rotary table is the rotation of the output end cover plate around its axis. Figure 10 This is a schematic diagram of the output end cover plate of the second turntable 1-2-2 and the third turntable 1-2-3. Two connecting grooves 1-2-4-1 are set in the same diameter direction on the output end cover plate, which are used to install the lower mechanism and the counterweight block respectively. The connecting holes 1-2-4-2 in the connecting grooves 1-2-4-1 are used to fix the lower mechanism and the counterweight block (which can be fixed by screws); a partition 1-2-4-3 is set between the two connecting grooves 1-2-4-1 so that they are not connected.

[0057] The rotary piezoelectric drive unit is now introduced by taking the first rotary table 1-2-1 as an example. The rotary piezoelectric drive unit structure and working principle of each level of rotary table are exactly the same. The rotary piezoelectric drive unit mainly includes a shaft ring 1-2-1-2, a friction plate 1-2-1-3, a pre-tightening magnet 1-2-1-4, a piezoelectric ceramic 1-2-1-7, and a driving magnet 1-2-1-8; wherein the fixed end of the piezoelectric ceramic 1-2-1-7 and the pre-tightening magnet 1-2-1-4 are both fixed on the installation base of the rotary piezoelectric drive unit (i.e., the base 1-2-1-1), and the movable end of the piezoelectric ceramic is driven by an external excitation signal to extend or retract along the preset movement direction; the pre-tightening magnet 1-2-1-4 is arranged opposite to the movable end of the piezoelectric ceramic, and there is a distance between the two; the driving magnet 1-2-1-8 and the friction plate 1-2-1-3 are bonded, and the two are The combined body is arranged between the pre-tightening magnet 1-2-1-4 and the active end of the piezoelectric ceramic, the collar 1-2-1-2 is a ferromagnetic material, the driving magnet 1-2-1-8 and the collar 1-2-1-2 are attracted by magnetic force and fix the friction plate 1-2-1-3 between the two; the driving magnet 1-2-1-8 and the pre-tightening magnet 1-2-1-4 are both single-pole magnetized, and the 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 adsorption force between the driving magnet and the collar, the driving magnet can only fit the active end of the piezoelectric ceramic and drive the shaft to rotate around its axis.

[0058] In this embodiment, the shaft ring 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-level friction plate 1-2-1-3 provides sufficient service life for the rotating table I1-2-1.

[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 sticking stage, the input voltage of the excitation signal changes slowly. In this stage, the piezoelectric ceramic extends or retracts with the slow change of voltage, driving the combination of the magnet and the friction plate to move slowly. Due to the friction between the combination and the collar under the action of the preload force, and due to the slow movement in 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 stage, the input voltage of the excitation signal changes rapidly. In this stage, the piezoelectric ceramics extend or contract rapidly with the rapid change of voltage, and the combination also moves rapidly. Due to the rapid movement, relative motion will occur between the combination and the collar. The friction force is dynamic friction. Under the action of dynamic friction, the collar retreats a certain angle Δθ, reducing the rotation angle from θ1 to θ2.

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

[0063] Now take the first rotating table 1-2-1 as an example to introduce the assembly. Figure 7 The figure shows a schematic diagram of the structure of the first rotating table, which includes a base 1-2-1-1, a shaft ring 1-2-1-2, a friction plate 1-2-1-3, a pre-tightening magnet 1-2-1-4, a magnet pressing 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 pressing 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 figure specifically illustrates the base structure of the first rotating table, which mainly includes a bearing limit platform 1-2-1-1-1, a shaft 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 driving magnet mounting platform 1-2-1-1-5, a wiring hole 1-2-1-1-6, a ceramic mounting groove 1-2-1-1-7 and a shaft ring fixing threaded hole 1-2-1-1-8.

[0064] During assembly, first fix the piezoelectric ceramic 1-2-1-7 in the ceramic mounting groove 1-2-1-1-7 by gluing, and discharge its wires through the wire arrangement hole 1-2-1-1-6; then embed the inner ring of the shaft collar 1-2-1-2 into the bearing limit platform 1-2-1-1-1, and limit it with the shaft shoulder 1-2-1-1-2; then insert the inner ring pressing cover into the inner ring of the shaft collar 1-2-1-2, wherein the inner ring pressing cover 1-2-1-9 is used for limiting; fix the shaft collar 1-2-1-2 on the base 1-2-1-1 by passing the screw through the countersunk hole of the inner ring pressing cover and screwing it into the threaded hole; fix the outer ring connecting cover 1-2-1-1 by gluing. 0 is fixed on the outer ring of the shaft ring 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 in the pre-tightening magnet mounting platform 1-2-1-1-4, and a screw is used to pass through the countersunk hole 1-2-1-5-2 of the magnet pressing cover and screwed into the corresponding threaded hole 1-2-1-1-3 to fix the pre-tightening magnet 1-2-1-4, and the friction plate 1-2-1-3 and the driving magnet 1-2-1-8 are glued and connected, and then they are nested together in the groove between the pre-tightening magnet 1-2-1-4 and the piezoelectric ceramic 1-2-1-7, and the pre-tightening magnet 1-2-1- 4 and the driving magnet 1-2-1-8 are both unipolar magnetized magnets, and the two repel each other, so that the driving magnet 1-2-1-8 is in close contact with the piezoelectric ceramic 1-2-1-7 after assembly. The pre-tightening magnet 1-2-1-4 is slightly higher than the driving magnet 1-2-1-8 in the axial height direction, so that the driving magnet 1-2-1-8 can be in close contact with the driving magnet mounting platform 1-2-1-1-5 after being driven by the piezoelectric ceramic 1-2-1-7. The shaft ring 1-2-1-2 is made of ferromagnetic material. Under the action of magnetic attraction, the connection body composed of the friction plate 1-2-1-3 and the driving magnet 1-2-1-8 can still be connected after the friction plate 1-2-1-3 is worn to a certain height. In order to maintain stable adsorption and friction with the shaft ring 1-2-1-2 and realize self-adsorption due to wear, the friction plate 1-2-1-3 is made of wear-resistant material, and the friction plate 1-2-1-3 provides sufficient service life for the turntable; then the screw is passed through the cover countersunk hole on 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, wherein the cover boss can be used for limiting the assembly; then the connection cover 1-2-1-11 is fixed to the outer ring connection 1-2-1-10 by passing the screw through the connection cover countersunk hole and screwing it into the outer ring connection cover threaded hole.

[0065] During operation, the microrobot of the present invention utilizes independent excitation signals to drive the gripping drive unit and the rotary piezoelectric drive units of the first, second, and third rotary stages. The excitation signals can be in the form of periodic sawtooth signals, with a single cycle of the signal waveform comprising a sticking phase in which the voltage varies linearly, and a sliding phase in which the voltage varies linearly. During the sticking phase, the absolute value of the slope of the voltage variation curve is small, and relative movement between the assembly and the output platform (the slider or collar in the present invention) does not occur. During the sliding phase, the absolute value of the slope of the voltage variation curve is large, and relative sliding occurs between the assembly and the output platform.

[0066] like Figure 11 As shown, in this embodiment, the bonding stage is selected as the voltage rising stage, and the sliding stage is selected as the voltage falling stage; in the clamping drive unit, the slider generates a net displacement d2 in the direction of the piezoelectric ceramic extension in each cycle, and the distance between the clamping arms of the clamp increases, thereby realizing the clamp release action. Figure 11 Under the action of the excitation signal shown, the rotating piezoelectric drive unit generates a net rotation angle θ2 in the clockwise direction in each cycle. It should be noted that by changing the waveform of the excitation signal (for example, the bonding stage is selected as the voltage drop stage, and the sliding stage is selected as the voltage rise stage), the output platform can generate a net displacement movement or a net rotation angle in the retraction direction of the piezoelectric ceramic. The present invention effectively reduces the wear effect of the friction pair by introducing a magnetic coupling wear adaptive compensation mechanism. After the friction plate or the collar 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 collar, the friction plate always maintains stable contact with the collar and maintains a relatively stable friction force; achieving cross-scale precise motion: using an optimized piezoelectric drive scheme, the robot can achieve high-precision motion in the micron and nanometer ranges, and can maintain stable stepping and positioning in the millimeter range through high-frequency periodic excitation, achieving cross-scale adaptability.

[0067] The above-described embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. Persons skilled in the art will readily appreciate that variations and modifications may be made without departing from the scope of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A long-life, cross-scale, multi-degree-of-freedom micro-robot, characterized in that: It comprises a clamping drive unit and a three-degree-of-freedom rotation drive unit, wherein the three-degree-of-freedom rotation drive unit comprises a first rotating platform, a second rotating platform and a third rotating platform, and all three rotating platforms have a base; the first rotating platform is horizontally arranged on its base, and its output end is fixedly connected to the base of the second rotating platform, driving the second rotating platform and its base to rotate in a vertical direction; the output end of the second rotating platform is connected to the base of the third rotating platform, driving the third rotating platform and its base to rotate in a vertical plane; the output end of the third rotating platform is connected to the clamping drive unit, driving the clamping drive unit to rotate in a vertical plane; the first rotating platform, the second rotating platform and the third rotating platform are driven by a rotary piezoelectric drive unit with the same structure; 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 rotating table; a clamping piezoelectric ceramic is fixed on both sides of the other end, and the movable end of the clamping piezoelectric ceramic is fixedly connected to a clamping plate; two carbon fiber rods are respectively fixed on the inner sides of the two clamping plates, and the two carbon fiber rods are arranged opposite to each other with a distance between the ends, and the 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, and the two parts of the clamp are respectively connected to the two sliders.

2. The long-life, cross-scale, multi-DOF micro-robot according to claim 1, characterized in that: The clamping drive unit also includes a spring and a clamping pre-tightening screw; the slider includes an upper slider plate and a lower slider plate that are connected to each other, and the upper slider plate and the lower slider plate are installed in parallel to form a carbon fiber rod mounting groove. The wall surface of the lower slider plate side in the carbon fiber rod mounting groove is provided with a slider boss, and the upper slider plate is provided with a slider through hole that passes through the upper slider plate in the thickness direction, and the lower slider plate is provided with a slider threaded hole at a position opposite to the slider through hole; after the carbon fiber rod is installed in the carbon fiber rod mounting groove, a clamping pre-tightening screw is used to pass 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 pre-tightening screw.

3. The long-life, cross-scale, multi-DOF micro-robot according to claim 2, characterized in that: 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; During the sticking stage, the input voltage of the excitation signal changes slowly. In this stage, the clamped piezoelectric ceramics extend or retract with the slow change of voltage, and 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 action of the preload force, and the slow movement in 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; During the sliding stage, the input voltage of the excitation signal changes rapidly. In this stage, the clamped piezoelectric ceramics extend or contract rapidly with the rapid change of voltage, and the combination also moves rapidly. Due to the rapid movement, relative motion will occur between the combination 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; The voltage change directions in the sticking stage and the sliding stage are opposite, so the clamping piezoelectric ceramic and the slider move in opposite directions in the two stages; within one cycle, each slider obtains a net displacement, the net displacement d2 = d1 - Δd, and the moving distance of the two parts of the clamping drive unit is 2*d2.

4. The long-life, cross-scale, multi-DOF micro-robot according to claim 1, characterized in that: The axis of the first rotating platform is vertical, and its output end rotates around the axis. The bases of the second and third rotating platforms each include a base extension plate, the length of which passes through the rotation center of the rotating platform on which it is located. The base extension plate of the second rotating platform is mounted on the output end of the first rotating platform, and the length of the base extension plate is collinear with the axis of the first rotating platform. The axis direction of the second rotating table is horizontal, and the base extension plate of the third rotating table is installed at the output end of the second rotating table and is perpendicular to the axis direction of the second rotating table; the axis direction of the third rotating table is horizontal, and one end of the clamping rod is fixed on the third rotating table, and the length direction of the clamping rod is perpendicular to the axis direction of the third rotating table.

5. The long-life, cross-scale, multi-DOF micro-robot according to claim 4, characterized in that: The rotary piezoelectric drive unit includes a shaft ring, a friction plate, a preload magnet, piezoelectric ceramics, 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 rotating piezoelectric drive unit, and the movable end of the piezoelectric ceramic is driven by an external excitation signal to extend or retract along a preset direction of movement; the pre-tightening magnet is arranged opposite to the movable end of the piezoelectric ceramic, and there is a distance between the two; the driving magnet and the friction plate are bonded, and the combination of the two is arranged between the pre-tightening magnet and the movable end of the piezoelectric ceramic, and the shaft ring is made of ferromagnetic material, and the driving magnet and the shaft ring are attracted by magnetic force and fix the friction plate between the two; the driving magnet and the pre-tightening magnet are both single-pole magnetized, and the 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 driving magnet and the pre-tightening magnet and the adsorption force between the driving magnet and the shaft ring, the driving magnet can only always fit the movable end of the piezoelectric ceramic and drive the shaft to rotate around its axis.

6. The long-life, cross-scale, multi-DOF micro-robot according to claim 4, characterized in that: The shaft collar includes an inner ring and an outer ring that can rotate relative to each other. The inner ring of the shaft collar is fixed to the base of the corresponding turntable, the combination of the friction plate and the driving magnet is connected to the outer ring of the shaft collar, and the output end of the corresponding turntable is fixedly connected to the outer ring of the shaft collar; the axial direction of the shaft collar is the axial direction of the corresponding turntable.

7. The long-life, cross-scale, multi-DOF micro-robot according to claim 4, characterized in that: 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; During the sticking stage, the input voltage of the excitation signal changes slowly. In this stage, the piezoelectric ceramic extends or retracts with the slow change of voltage, driving the combination of the magnet and the friction plate to move slowly. Due to the friction between the combination and the collar under the action of the preload force, and due to the slow movement in 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 stage, the input voltage of the excitation signal changes rapidly. In this stage, the piezoelectric ceramics extend or contract rapidly with the rapid change of voltage, and the combination also moves rapidly. Due to the rapid movement, relative motion will occur between the combination and the collar. The friction force is dynamic friction. Under the action of dynamic friction, the collar retreats a certain angle Δθ, reducing the rotation angle from θ1 to θ2. The voltage changes in the sticking stage and the sliding stage are in opposite directions, so the piezoelectric ceramic moves in opposite directions in the two stages, and the corresponding shaft ring rotates in opposite directions in the two stages; within one cycle, the shaft ring obtains a net rotation angle θ2 = θ1 - Δθ.

8. The long-life, cross-scale, multi-DOF micro-robot according to claim 4, characterized in that: The output end of the second rotating platform is further provided with a counterweight block, which is installed on the extension line of the base extension plate of the third rotating platform to balance the weight of the third rotating platform; The output end of the third rotating platform is also provided with a counterweight block, which is installed on the extension line of the clamping rod and is used to balance the weight of the clamping drive unit.

9. The long-life, cross-scale, multi-DOF micro-robot according to claim 1, characterized in that: The clamping drive unit, and the rotary piezoelectric drive units of the first rotary stage, the second rotary stage, and the third rotary stage are driven respectively by independent excitation signals.

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