A force couple dithered piezoelectric stick-slip rotary platform and a driving method thereof

Abstract

The application discloses a force couple stirring type piezoelectric stick-slip rotary platform and a driving method thereof, relates to the technical field of precise driving and positioning of piezoelectric linear feed drives, and comprises an outside platform and an inside platform nested in the inside of the outside platform, and a hinge is arranged above the inside platform; a piezoelectric linear feed drive is fixedly connected to the middle position of the hinge, an upper stick-slip pressure head is fixedly arranged below one end of the hinge, and a lower stick-slip pressure head is fixedly arranged below the other end of the hinge. The force couple stirring type piezoelectric stick-slip rotary platform and the driving method thereof adopt the above structure, can convert the high-frequency expansion and contraction movement of the piezoelectric linear feed drive into the rotation of the inside and outside platforms, can realize bidirectional rotation by adjusting the driving voltage, and can make the inside platform or the outside platform rotate by adjusting the different fixing modes of the inside and outside platforms, so that the application has the advantages of compact structure, large stroke, high positioning precision, rich movement modes and simple control.

Description

Technical Field

[0001] This invention relates to the field of precision driving and positioning technology for piezoelectric linear feed actuators, and in particular to a force couple-driven piezoelectric stick-slip rotary platform and its driving method. Background Technology

[0002] Piezoelectric linear feed actuators are widely used in precision drive and positioning systems in special environments due to their fast response speed, simple structure, and immunity to electromagnetic interference. Existing piezoelectric drive principles primarily rely on friction or tooth meshing for transmission, converting the periodic micro-motion of the piezoelectric stator into the stepping motion of the mover. However, friction is complex and uncertain, and tooth meshing can easily cause collisions and impacts. These motor drive methods suffer from complex control and unstable operation, requiring complex systems and sensor configurations for precise positioning and control. Complex closed-loop control systems not only require high-precision sensors and controllers across large scales, increasing equipment cost and size, limiting miniaturization, but also reducing reliability in practical applications.

[0003] Stick-slip actuators induce two processes within a single drive cycle: "stickiness" and "sliding." The output displacement during the "stickiness" process is the same as the output displacement for one drive cycle. To achieve effective stick-slip actuation and avoid significant friction during the "sliding" process that could cause the mechanism to retract, existing piezoelectric stick-slip actuators often use asymmetrical voltage signals to excite the piezoelectric motor. This utilizes the inverse piezoelectric effect to cause the piezoelectric material to slowly elongate and rapidly shorten. The different frictional forces generated during these two processes result in the "stickiness" and "sliding" processes. However, traditional rotary stick-slip actuators typically suffer from drawbacks such as non-compact structure, unbalanced forces, radial forces, and, over time, shaft deflection affecting platform accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide a force couple-driven piezoelectric stick-slip rotary platform and its driving method, which solves the problems of complex structure and low precision of existing stick-slip driving methods.

[0005] To achieve the above objectives, the present invention provides a force-couple driven piezoelectric stick-slip rotary platform, comprising an outer platform and an inner platform nested inside the outer platform. A hinge is provided above the inner platform, and washers are provided on both sides of the hinge. The hinge is fixed to the inner platform by the washers and connectors. A piezoelectric linear feed driver is fixedly connected to the middle position of the hinge. An upper stick-slip pressure head is fixedly provided below one end of the hinge, and a lower stick-slip pressure head is fixedly provided below the other end of the hinge. Both the lower stick-slip pressure head and the upper stick-slip pressure head are in contact with the outer platform.

[0006] Preferably, the outer platform, the inner platform, and the hinge are all provided with a plurality of through holes.

[0007] A driving method for a force-couple driven piezoelectric stick-slip rotary platform includes the following steps:

[0008] Step S1: In the initial state, the inner platform is fixed, the outer platform is in a free state, the piezoelectric linear feed driver is kept off, and the entire piezoelectric stick-slip micro-motion platform remains stationary.

[0009] Step S2: Apply a sawtooth voltage that rises slowly and falls rapidly to the piezoelectric linear feed driver. During the slow rise phase of the sawtooth voltage, the piezoelectric linear feed driver slowly elongates, the drive hinge slowly deforms, and the upper and lower stick-slip heads are offset in a clockwise direction. Friction is generated at the contact points between the upper and lower stick-slip heads and the outer platform, forming a couple that acts on the outer platform, creating a sticky state. The stick-slip heads cause the outer platform to rotate at an angle of α.

[0010] Step S3: During the rapid decrease of the sawtooth voltage, the piezoelectric linear feed actuator rapidly retracts and returns to its original length. The drive hinge quickly returns to its original shape, causing the upper and lower stick-slip pressure heads to slightly shift counterclockwise and return to their original positions. The frictional force generated at the contact point between the upper and lower stick-slip pressure heads and the outer platform is insufficient to cause the outer platform to shift, forming a sliding state. The upper and lower stick-slip pressure heads deflect counterclockwise and return to their original positions. The outer platform remains in the position it was in in step S2. The upper and lower stick-slip pressure heads deflect relative to the outer platform by an angle of α.

[0011] Preferably, in step S2, under the slowly increasing voltage drive, the upper and lower stick-slip pressure heads are in a sticky state with the outer platform, and the upper and lower stick-slip pressure heads drive the outer platform to deflect clockwise together, with a deflection angle of α.

[0012] Preferably, in step S3, under the rapidly decreasing voltage drive, the upper and lower stick-slip pressure heads are in a sliding state with the outer platform, the upper and lower stick-slip pressure heads deflect counterclockwise, the outer platform remains stationary, the relative deflection angle between the upper and lower stick-slip pressure heads and the outer platform is α, and within one cycle, the outer platform deflects by an angle α relative to the inner platform.

[0013] Therefore, the piezoelectric stick-slip rotary platform and its driving method based on the above-described structure have the following beneficial effects:

[0014] (1) It does not require setting up high-scale, high-precision sensors and controllers to achieve accurate positioning, thus reducing costs.

[0015] (2) During the movement, the upper stick-slip pressure head and the lower stick-slip pressure head form a “sticky” and “sliding” process with the outer platform through the slowly rising and rapidly falling sawtooth driving voltage. The hinge is controlled to deform through the high frequency extension and retraction of the piezoelectric linear feed driver, thereby realizing the reliable movement of the upper stick-slip pressure head and the lower stick-slip pressure head.

[0016] (3) It can realize bidirectional motion of the mover. No structural adjustment is required. Only by adjusting the driving voltage and changing the order of the "sticking" and "sliding" processes between the upper and lower stick-slip pressure heads and the outer platform, the deflection direction of the outer platform at any time can be controlled.

[0017] (4) The inner platform and the outer platform can move in both directions respectively. No structural adjustment is required. Only the fixing method of the inner platform and the outer platform needs to be adjusted. When the inner platform is fixed, the outer platform can move in both directions. When the outer platform is fixed, the inner platform can move in both directions.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention;

[0020] Figure 2 The state flowchart of the driving principle of this invention includes (a) the initial state diagram of the piezoelectric stick-slip micro-motion platform, (b) the state diagram of the outer platform rotating at a small angle, and (c) the state diagram of the upper stick-slip pressure head and the lower stick-slip pressure head being relatively deflected relative to the outer platform.

[0021] Figure 3 This is a voltage diagram of the piezoelectric linear feed driver when the outer platform is driven clockwise according to the present invention;

[0022] Figure 4 This is a diagram showing the deflection angle of the upper and lower adhesive-slip pressure heads when the outer platform is driven clockwise according to the present invention.

[0023] Figure 5 This is a diagram showing the deflection angle of the outer platform when it is driven clockwise according to the present invention.

[0024] Reference numerals: 1. Outer platform; 2. Inner platform; 3. Hinge; 4. Shim; 5. Piezoelectric linear feed driver; 6. Upper stick-slip pressure head; 7. Lower stick-slip pressure head. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] Example

[0028] Please see Figure 1-5 This invention provides a force-couple driven piezoelectric stick-slip rotary platform, comprising an outer platform 1 and an inner platform 2 nested inside the outer platform 1, which can rotate relative to the outer platform 1. A hinge 3 is provided on the upper part of the inner platform 2, and washers 4 are provided on both sides of the hinge 3. The hinge 3 is fixed to the inner platform 2 by the washers 4 and connecting parts, which are screws. A piezoelectric linear feed driver 5 is fixedly connected at the middle position of the hinge 3, and the piezoelectric linear feed driver 5 can drive the hinge 3 to deform. An upper stick-slip pressure head 6 is fixedly provided below one end of the hinge 3, and a lower stick-slip pressure head 7 is fixedly provided below the other end of the hinge 3. Both the lower stick-slip pressure head 7 and the upper stick-slip pressure head 6 are in contact with the outer platform 1, and the stick-slip effect is achieved through friction. Several through holes are provided on the outer platform 1, the inner platform 2, and the hinge 3, and screws are passed through the through holes for fixation. During the driving process, the piezoelectric linear feed driver 5 is driven by a sawtooth driving voltage that rises slowly and falls rapidly. The piezoelectric linear feed driver 5 undergoes relative deformation, which in turn causes the hinge 3 to deform. The deformation of the hinge 3 causes the upper stick-slip pressure head 6 and the lower stick-slip pressure head 7 to undergo "sticky" and "sliding" movements with the outer platform 1, which in turn causes the outer platform 1 to rotate relative to the inner platform 2.

[0029] Figure 2 The flowchart of the driving process of this invention is shown in the figure. A driving method for a force couple-driven piezoelectric stick-slip rotating platform can drive the inner and outer platforms to rotate separately. When driving a certain platform, it can generate bidirectional rotation. Taking the clockwise driving of the outer platform 1 as an example, the method includes the following steps:

[0030] Step S1: In the initial state, the inner platform 2 is fixed, the outer platform 1 is in a free state, the piezoelectric linear feed driver 5 is kept de-energized, and the entire piezoelectric stick-slip micro-motion platform remains stationary without displacement.

[0031] Step S2: A sawtooth voltage with a slow rise and rapid fall is applied to the piezoelectric linear feed driver 5. During the slow rise of the sawtooth voltage, the piezoelectric linear feed driver 5 slowly elongates, and the drive hinge slowly deforms, causing the upper stick-slip head 6 and the lower stick-slip head 7 to shift slightly in the clockwise direction. Due to the slow shift speed, a large frictional force is generated at the contact point between the upper stick-slip head 6 and the lower stick-slip head 7 and the outer platform 1, forming a force couple that acts on the outer platform, creating a sticky state. The stick-slip head causes the outer platform 1 to rotate slightly, with a deflection angle of α.

[0032] Step S3: During the rapid decrease of the sawtooth voltage, the piezoelectric linear feed driver 5 rapidly retracts and returns to its original length. The drive hinge quickly returns to its original shape, causing the upper stick-slip head 6 and the lower stick-slip head 7 to shift slightly counterclockwise and return to their original positions. Due to the fast shift speed, the frictional force generated at the contact point between the upper stick-slip head 6 and the lower stick-slip head 7 and the outer platform 1 is very small and insufficient to cause the outer platform 1 to shift, forming a sliding state. The upper stick-slip head 6 and the lower stick-slip head 7 deflect counterclockwise and return to their original positions. The outer platform 1 remains in the position it was in in step S2. The upper stick-slip head 6 and the lower stick-slip head 7 deflect relative to the outer platform 1 by an angle of α.

[0033] In step S2, under the slowly increasing voltage drive, the upper stick-slip pressure head 6 and the lower stick-slip pressure head 7 are in a sticky state with the outer platform 1. The upper stick-slip pressure head 6 and the lower stick-slip pressure head 7 drive the outer platform 1 to deflect clockwise together, and the deflection angle is α.

[0034] In step S3, driven by a rapidly decreasing voltage, the upper stick-slip pressure head 6 and the lower stick-slip pressure head 7 are in a sliding state with the outer platform 1. The upper stick-slip pressure head 6 and the lower stick-slip pressure head 7 deflect counterclockwise, while the outer platform 1 remains stationary. The relative deflection angle between the upper stick-slip pressure head 6 and the lower stick-slip pressure head 7 and the outer platform 1 is α. Within one cycle, the outer platform 1 deflects by an angle α relative to the inner platform 2.

[0035] This embodiment takes clockwise driving of the outer platform 1 as an example. If counterclockwise driving of the outer platform 1 is required, the sawtooth voltage shape in the above steps can be changed. This is only a change in the driving voltage, without adjusting the structure, and the outer platform 1 can move clockwise or counterclockwise at any time. When driving the inner platform 2, it is only necessary to fix the outer platform 1 and allow the inner platform 2 to rotate. The specific driving principle is the same.

[0036] Figure 3 This is a voltage diagram of the piezoelectric linear feed driver 5 when the outer platform is driven clockwise according to the present invention. The horizontal axis t represents time, and the vertical axis U represents voltage.

[0037] Figure 4 This is a diagram showing the deflection angles of the upper stick-slip pressure head 6 and the lower stick-slip pressure head 7 when the outer platform 1 is driven clockwise according to the present invention. The horizontal axis t represents time, and the vertical axis represents angle.

[0038] Figure 5 This is a diagram showing the deflection angle of the outer platform 1 when it is driven clockwise according to the present invention. The horizontal axis t represents time, and the vertical axis represents angle.

[0039] Therefore, the present invention provides a force couple-driven piezoelectric stick-slip rotary platform and its driving method, which can convert the high-frequency extension and retraction motion of the piezoelectric linear feed driver into the rotation of the inner and outer platforms. By adjusting the driving voltage, bidirectional rotation can be achieved. By adjusting the different fixing methods of the inner and outer platforms, the inner or outer platform can be rotated respectively. It has the advantages of large stroke, high positioning accuracy, compact structure, rich motion modes, and simple control.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A force-couple driven piezoelectric stick-slip rotary platform, characterized in that: The device includes an outer platform and an inner platform nested inside the outer platform. A hinge is provided above the inner platform, and washers are provided on both sides of the hinge. The hinge is fixed to the inner platform by the washers and connectors. A piezoelectric linear feed driver is fixedly connected to the middle position of the hinge. An upper stick-slip pressure head is fixedly provided below one end of the hinge, and a lower stick-slip pressure head is fixedly provided below the other end of the hinge. Both the lower stick-slip pressure head and the upper stick-slip pressure head are in contact with the outer platform. The driving method for the above-mentioned torque-driven piezoelectric stick-slip rotary platform includes the following steps: Step S1: In the initial state, the inner platform is fixed, the outer platform is in a free state, the piezoelectric linear feed driver is kept off, and the entire piezoelectric stick-slip micro-motion platform remains stationary. Step S2: Apply a sawtooth voltage that rises slowly and falls rapidly to the piezoelectric linear feed driver. During the slow rise phase of the sawtooth voltage, the piezoelectric linear feed driver slowly elongates, the drive hinge slowly deforms, and the upper and lower stick-slip heads are offset in a clockwise direction. Friction is generated at the contact points between the upper and lower stick-slip heads and the outer platform, forming a couple that acts on the outer platform, creating a sticky state. The stick-slip heads cause the outer platform to rotate at an angle of α. Step S3: During the rapid decrease of the sawtooth voltage, the piezoelectric linear feed driver rapidly retracts and returns to its original length. The drive hinge quickly returns to its original shape, causing the upper and lower stick-slip pressure heads to shift counterclockwise and return to their original positions. The frictional force generated at the contact point between the upper and lower stick-slip pressure heads and the outer platform is insufficient to cause the outer platform to shift, forming a sliding state. The upper and lower stick-slip pressure heads deflect counterclockwise and return to their original positions. The outer platform remains in the position it was in in step S2. The upper and lower stick-slip pressure heads deflect relative to the outer platform by an angle of α. In step S2, under the slowly increasing voltage, the upper and lower stick-slip pressure heads are in a sticky state with the outer platform. The upper and lower stick-slip pressure heads drive the outer platform to deflect clockwise together, with a deflection angle of α.

2. The force-couple driven piezoelectric stick-slip rotary platform according to claim 1, characterized in that: The outer platform, the inner platform, and the hinge are all provided with several through holes.

3. The force-couple driven piezoelectric stick-slip rotary platform according to claim 2, characterized in that: In step S3, under the rapidly decreasing voltage, the upper and lower stick-slip pressure heads are in a sliding state with the outer platform. The upper and lower stick-slip pressure heads deflect counterclockwise, while the outer platform remains stationary. The relative deflection angle between the upper and lower stick-slip pressure heads and the outer platform is α. Within one cycle, the outer platform deflects by an angle α relative to the inner platform.

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