Piezoelectric-driven two-degree-of-freedom pointing mechanism

Abstract

The invention discloses a two-degree-of-freedom pointing mechanism driven by piezoelectricity. The two-degree-of-freedom pointing mechanism comprises an L-shaped support, first piezoelectric ceramics, second piezoelectric ceramics, a first rotor, a second rotor, a first pressing plate, a second pressing plate, a first flange, a second flange, a first bearing, a second bearing, a first sensor and a second sensor. The piezoelectric stator is directly driven by single-phase sinusoidal voltage, the driving foot is in direct contact with the rotor, elliptical motion of the driving foot is converted into rotation motion of the rotor through a friction effect, and blades are driven to move to change pitching and longitudinal angles of the camera. The piezoelectric-driven two-degree-of-freedom pointing mechanism designed by the invention adopts a structural function integrated design method, and is more compact and larger in dynamic range.

Description

Technical Field

[0001] The invention belongs to the field of aerospace instruments, and in particular relates to a piezoelectric driven two-degree-of-freedom pointing mechanism. Background Art

[0002] Space pointing mechanisms are often used as one of the core components in many current mechanical devices. In remote sensing observation, optical imaging and other related equipment, the demand for lightweight, miniaturization and high precision is increasing, and the basic characteristics of stability, anti-interference and durability are gradually increasing.

[0003] The existing technology uses electromagnetic motor drive. Since it first converts current, then the magnetic field force drives the motor to rotate, and then the motor drives through gears or conveyor belts, its complex structure and the space volume required for electromagnetic drive. What is more important is that in order to improve the performance and reliability of this type of drive, the volume has to be continuously expanded. At the same time, additional means must be used to effectively shield the electromagnetic interference it generates, making its application prospects in space observation instruments not optimistic.

[0004] As a new type of actuator directly driven by the inverse piezoelectric effect and the friction principle, the piezoelectric motor has the advantages of fast response, no electromagnetic interference, high precision, and compact structure. It has been successfully used in the fields of aviation and precision drive. Using piezoelectric motors instead of electromagnetic motors to drive the two-dimensional pointing mechanism can greatly simplify the two-dimensional pointing structure, reduce complexity, and improve operation accuracy and stability. However, the existing two-degree-of-freedom pointing mechanisms have poor accuracy, slow response, and large size. Summary of the invention

[0005] The present invention aims to provide a piezoelectric driven two-degree-of-freedom pointing mechanism to solve the technical problems of large volume and low precision of the existing two-degree-of-freedom pointing mechanism.

[0006] A piezoelectric driven two-degree-of-freedom pointing mechanism comprises an L-shaped bracket, a first piezoelectric ceramic, a second piezoelectric ceramic, a first rotor, a second rotor, a first pressure plate, a second pressure plate, a first flange, a second flange, a first bearing, a second bearing, a first sensor and a second sensor;

[0007] The L-shaped bracket includes a first bracket and a second bracket; the first bracket and the second bracket are connected to form an L-shaped structure; the first bracket and the second bracket are U-shaped structures; the first stator base is connected to the groove of the first bracket through four flexible hinges; the second stator base is connected to the groove of the first bracket through four flexible hinges; the first fixing groove is connected to the top of the first bracket, and the second fixing groove is connected to the top of the second bracket; the second fixing groove is used to connect the first pressure plate, and the first fixing groove is used to connect the second pressure plate; the top of the first stator base and the second stator are both provided with two semicircular driving feet; the bottom of the groove of the first bracket and the second bracket are provided with a pre-pressure groove for placing a pre-pressure spring to provide positive pressure to the first stator base and the second stator base;

[0008] The first rotor and the second rotor are stepped cylindrical structures, which are sequentially connected by a cylindrical rotor driving surface, an inner ring boss and a third bearing, and the rotor driving surface is in direct contact with the driving foot; the first rotor causes the driving foot to make an elliptical motion through the vibration of the first stator base, and drives the first rotor to rotate around the X axis through the friction of the rotor driving surface; the second rotor causes the driving foot to make an elliptical motion through the vibration of the second stator base, and drives the second rotor to rotate around the Y axis through the friction of the rotor driving surface; the third bearing is used to fix the first bearing and the second bearing respectively, and the inner ring boss is in contact with the inner ring of the first bearing and the second bearing respectively to limit the position of the first bearing and the second bearing; the first bearing is respectively interference fit with the first rotor and the second rotor; the end of the third bearing is fixed to the part;

[0009] The first pressing plate is used to fix the first bearing; the second pressing plate is used to fix the second bearing;

[0010] The first piezoelectric ceramic and the second piezoelectric ceramic are rectangular structures, the negative electrode is a complete rectangular electrode, and the positive electrode is divided into four rectangular pieces; the negative electrode of the first piezoelectric ceramic is directly attached to both sides of the first stator substrate; the negative electrode of the second piezoelectric ceramic is directly attached to both sides of the second stator substrate; the first stator substrate and the second stator substrate generate elliptical motion through diagonal excitation;

[0011] The first sensor and the second sensor are fixed on the first bracket and the second bracket respectively, and are used to measure the rotation speed of the first rotor and the second rotor.

[0012] Furthermore, the piezoelectric ceramic is excited by single-phase electricity to generate vibration through the inverse piezoelectric effect, and at the same time, the first stator matrix is ​​excited to form the same vibration, so that the driving foot generates standing wave motion and drives the first rotor to rotate.

[0013] Furthermore, the first stator matrix and the second stator matrix are combined with the second piezoelectric ceramic and the first piezoelectric ceramic to form two piezoelectric stators, and the piezoelectric stators are driven by a composite mode of first-order longitudinal vibration and second-order bending vibration.

[0014] Furthermore, the third bearing end is fixed with a flange or bolts.

[0015] Furthermore, both sides of the first pressing plate and the second pressing plate are connecting surfaces, four second bolt holes are arranged on the connecting surfaces, and an inner boss is arranged between the first pressing plate and the second pressing plate; a circular through hole is arranged in the center of the first pressing plate and the second pressing plate, a circle of circular bosses is arranged on the inner side of the bottom of the circular through hole, the surface of the circular boss is the side contact surface of the bearing, and the side wall of the circular through hole is the outer ring contact surface of the bearing;

[0016] The contact surface of the outer ring of the bearing contacts the surface of the outer ring of the first bearing, and the two are interference fit; the contact surface of the side surface of the bearing contacts the plane of the outer ring of the first bearing for limiting position; the first pressing plate is fixed in the second fixing groove, and is limited by the inner boss and the connecting surface, and the first fixing bolt cooperates with the second bolt hole and the threaded hole on the second fixing groove to tighten the first pressing plate;

[0017] The contact surface of the bearing outer ring contacts the surface of the second bearing outer ring, and the two are interference fit; the contact surface of the bearing side contacts the plane of the second bearing outer ring for limiting position; the second pressure plate is fixed in the second fixing groove, and is limited by the inner boss and the connecting surface; the second fixing bolt cooperates with the second bolt hole and the threaded hole on the second fixing groove to tighten the second pressure plate.

[0018] The piezoelectric driven two-degree-of-freedom pointing mechanism of the present invention has the following advantages:

[0019] The stator base and the L-shaped bracket of the present invention adopt an integrated design method, and the structure is compact. The present invention adopts a piezoelectric driving method, which can avoid electromagnetic interference and improve accuracy and response speed.

[0020] The piezoelectric motor in the present invention is a new type of actuator directly driven by the inverse piezoelectric effect and the friction principle, and has the advantages of fast response, no electromagnetic interference, high precision, compact structure, etc. Using a piezoelectric motor instead of an electromagnetic motor to drive a two-dimensional spatial pointing mechanism can greatly simplify the two-dimensional spatial pointing structure, reduce complexity, and improve operating accuracy and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a piezoelectric driven two-degree-of-freedom pointing mechanism;

[0022] Figure 2 It is an exploded diagram of a piezoelectric driven two-degree-of-freedom pointing mechanism according to the present invention;

[0023] Figure 3 It is a schematic diagram of the L-shaped bracket structure in the present invention;

[0024] Figure 4 It is a structural schematic diagram of the pressing plate in the present invention;

[0025] Figure 5 is a schematic diagram of the rotor structure of the present invention;

[0026] Figure 6 is a schematic diagram of the movement of the piezoelectric stator after excitation in the present invention;

[0027] Figure 7 is a schematic diagram of a piezoelectric ceramic sheet in the present invention;

[0028] Explanation of the marks in the figure: 1. first flange; 2. first pressure plate; 3. first fixing bolt; 4. first bearing; 5. first rotor; 6. first sensor; 7. second flange; 8. second pressure plate; 9. second fixing bolt; 10. second bearing; 11. second rotor; 12. second sensor; 13. first piezoelectric ceramic; 14. L-shaped bracket; 15. second piezoelectric ceramic; 16. load; 141. first bracket 1; 142. second bracket; 143. first stator base; 144. second stator base; 145. flexible hinge; 146. pre-pressure groove; 147. driving foot; 148. first fixing groove; 149. second fixing groove; 21. second bolt hole; 22. inner boss; 23. bearing side contact surface; 24. bearing outer ring contact surface; 25. connection surface; 51. third bearing; 52. inner ring boss; 53. rotor driving surface. DETAILED DESCRIPTION

[0029] In order to better understand the purpose, structure and function of the present invention, a piezoelectric driven two-degree-of-freedom pointing mechanism of the present invention is further described in detail below with reference to the accompanying drawings.

[0030] like Figure 1 As shown, the piezoelectrically driven two-degree-of-freedom pointing mechanism with load diagram includes the designed piezoelectrically driven two-degree-of-freedom pointing mechanism and load 16.

[0031] like Figure 2 The piezoelectric driven two-degree-of-freedom pointing mechanism of the present invention comprises an L-shaped bracket 14, a first piezoelectric ceramic 13, a second piezoelectric ceramic 15, a first rotor 5, a second rotor 11, a first pressure plate 2, a second pressure plate 8, a first flange 1, a second flange 7, a first bearing 4, a second bearing 10, a first sensor 6 and a second sensor (12).

[0032] like Figure 3As shown, the L-shaped bracket 14 includes a first bracket 141 and a second bracket 142; the first bracket 141 and the second bracket 142 are connected to form an L-shaped structure; the first bracket 141 and the second bracket 142 are U-shaped structures; the first stator base 143 is connected to the groove of the first bracket 141 through four flexible hinges 145; the second stator base 144 is connected to the groove of the first bracket 142 through four flexible hinges 145; the first fixing groove 148 is connected to the top of the first bracket 141, and the second fixing groove 149 is connected to the top of the second bracket 142; the second fixing groove 149 is used to connect the first pressure plate 2, and the first fixing groove 148 is used to connect the second pressure plate 8; the tops of the first stator base 143 and the second stator 144 are both provided with two semicircular driving feet 147; the bottoms of the grooves of the first bracket 141 and the second bracket 142 are both provided with pre-pressure grooves 146 for placing pre-pressure springs to provide positive pressure to the first stator base 143 and the second stator base 144.

[0033] Figure 5 As shown, the first rotor 5 and the second rotor 11 are stepped cylindrical structures, which are sequentially connected by a cylindrical rotor driving surface 53, an inner ring boss 52 and a third bearing 51. The rotor driving surface 53 is in direct contact with the driving foot 147. The first rotor 5 causes the driving foot 147 to make an elliptical motion through the vibration of the first stator base 143, and the first rotor 5 is driven by the friction of the rotor driving surface 53 to rotate around the X axis. The second rotor 11 causes the driving foot 147 to make an elliptical motion through the vibration of the second stator base 144, and the second rotor 11 is driven by the friction of the rotor driving surface 53 to rotate around the Y axis. The third bearing surface 51 is used to fix The first bearing 4 is fixed, and the inner ring boss 52 contacts the inner ring of the first bearing 4 to limit the position of the first bearing 4; the first bearing 4 and the first rotor 5 have an interference fit, and can also be fastened by other fixing methods; the end of the third bearing 51 cooperates with the first flange 1 and can be fixed by bolts and other parts; the third bearing surface 51 is used to fix the second bearing 10, and the inner ring boss 52 contacts the inner ring of the second bearing 10 to limit the position of the second bearing 10; the second bearing 10 and the second rotor 11 have an interference fit, and can also be fastened by other fixing methods; the end of the third bearing surface 51 cooperates with the second flange 7 and can be fixed by bolts and other parts.

[0034] The second flange 7 has the same structure as the first flange 1 and is used to fix the load.

[0035] like Figure 4 As shown, the first pressure plate 2 is used to fix the first bearing 4; the second pressure plate 8 is used to fix the second bearing 10;

[0036] Both sides of the first pressing plate 2 and the second pressing plate 8 are connecting surfaces 25, and four second bolt holes 21 are provided on the connecting surface 25. An inner boss 22 is provided between the first pressing plate 2 and the second pressing plate 8. A circular through hole is provided in the center of the first pressing plate 2 and the second pressing plate 8, and a circle of circular bosses is provided on the inner side of the bottom of the circular through hole. The surface of the circular boss is the bearing side contact surface 23, and the side wall of the circular through hole is the bearing outer ring contact surface 24.

[0037] The bearing outer ring contact surface 24 contacts the outer ring surface of the first bearing 4, and the two are interference fit; the bearing side contact surface 24 contacts the outer ring plane of the first bearing 4 for limiting position; the first pressure plate 2 is fixed in the second fixing groove 149, and is limited by the inner boss 22 and the connecting surface 25, and the first fixing bolt 3 cooperates with the second bolt hole 21 and the threaded hole on the second fixing groove 149 to tighten the first pressure plate 2;

[0038] The bearing outer ring contact surface 24 contacts the outer ring surface of the second bearing 10, and the two are interference fit; the bearing side contact surface 23 contacts the outer ring plane of the second bearing 10 for limiting; the second pressure plate 8 is fixed in the second fixing groove 149, and is limited by the inner side boss 22 and the connecting surface 25, and the second fixing bolt 9 cooperates with the second bolt hole 21 and the threaded hole on the second fixing groove (149) to tighten the second pressure plate 8.

[0039] The first piezoelectric ceramic 13 and the second piezoelectric ceramic 15 are rectangular structures, the negative electrode of which is a complete rectangular electrode, and the positive electrode is divided into four rectangular blocks; the negative electrode of the first piezoelectric ceramic 13 is directly attached to both sides of the first stator substrate 143; the negative electrode of the second piezoelectric ceramic 15 is directly attached to both sides of the second stator substrate 144; the first stator substrate 143 and the second stator substrate 144 generate elliptical motion through diagonal excitation;

[0040] The first sensor 6 and the second sensor 12 are fixed on the first bracket 141 and the second bracket 142 respectively, and are used to measure the rotation speed of the first rotor 5 and the second rotor 11 .

[0041] The piezoelectric stator 13 adopts a single-phase electrical excitation method, and through the inverse piezoelectric effect, the piezoelectric stator driving foot 147 generates a standing wave motion, drives the first rotor 5 to rotate, and the rotor drives the blades to move to change the pitch and longitudinal angles of the camera.

[0042] The first stator matrix 143 and the second stator matrix 144 are combined with the second piezoelectric ceramic 15 and the first piezoelectric ceramic 13 to form two piezoelectric stators. The piezoelectric stators are driven by a composite mode of first-order longitudinal vibration and second-order bending vibration.

[0043] like Figure 6 FIG. 1 is a schematic diagram of the movement of the piezoelectric stator after excitation in the present invention. Figure 7 Shown is a schematic diagram of the piezoelectric ceramic sheet in the present invention.

[0044] Compared with the traditional electromagnetic driving method and the memory alloy driving method, the piezoelectric driven two-degree-of-freedom pointing mechanism designed in the present invention is more compact, thinner and has a larger dynamic range.

[0045] The piezoelectric motor in the present invention is a new type of actuator directly driven by the inverse piezoelectric effect and the friction principle, and has the advantages of fast response, no electromagnetic interference, high precision, compact structure, etc. Using a piezoelectric motor instead of an electromagnetic motor to drive a two-dimensional spatial pointing mechanism can greatly simplify the two-dimensional spatial pointing structure, reduce complexity, and improve operating accuracy and stability.

[0046] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A piezoelectric driven two-degree-of-freedom pointing mechanism, characterized in that: It comprises an L-shaped bracket (14), a first piezoelectric ceramic (13), a second piezoelectric ceramic (15), a first rotor (5), a second rotor (11), a first pressure plate (2), a second pressure plate (8), a first flange (1), a second flange (7), a first bearing (4), a second bearing (10), a first sensor (6) and a second sensor (12); The L-shaped bracket (14) comprises a first bracket (141) and a second bracket (142); the first bracket (141) and the second bracket (142) are connected to form an L-shaped structure; the first bracket (141) and the second bracket (142) are U-shaped structures; the first stator base (143) is connected to the groove of the first bracket (141) through four flexible hinges (145); the second stator base (144) is connected to the groove of the first bracket (142) through four flexible hinges (145); the first fixing groove (148) is connected to the groove of the first bracket (141); The top end of the second bracket (142) is provided with a second fixing groove (149) connected to the top end of the second bracket (142); the second fixing groove (149) is used to connect the first pressing plate (2), and the first fixing groove (148) is used to connect the second pressing plate (8); the top ends of the first stator base (143) and the second stator (144) are both provided with two semicircular driving feet (147); the bottom ends of the grooves of the first bracket (141) and the second bracket (142) are both provided with pre-pressure grooves (146) for placing pre-pressure springs to provide positive pressure to the first stator base (143) and the second stator base (144); The first rotor (5) and the second rotor (11) are stepped cylindrical structures, which are sequentially connected to form a cylindrical rotor driving surface (53), an inner ring boss (52) and a third bearing (51); the rotor driving surface (53) is in direct contact with the driving foot (147); the first rotor (5) causes the driving foot (147) to perform elliptical motion through the vibration of the first stator base (143), and the first rotor (5) is driven to rotate around the X-axis through the friction of the rotor driving surface (53); the second rotor (11) causes the driving foot (147) to perform elliptical motion through the vibration of the second stator base (144); The driving foot (147) is caused to perform elliptical motion, and the friction force of the rotor driving surface (53) drives the second rotor (11) to rotate around the Y axis; the third bearing (51) is used to fix the first bearing (4) and the second bearing (10), and the inner ring boss (52) is respectively in contact with the inner ring of the first bearing (4) and the second bearing (10) to limit the position of the first bearing (4) and the second bearing (10); the first bearing (4) is respectively interference fit with the first rotor (5) and the second rotor (11); the end of the third bearing (51) is fixed to the part; The first pressing plate (2) is used to fix the first bearing (4); the second pressing plate (8) is used to fix the second bearing (10); The first piezoelectric ceramic (13) and the second piezoelectric ceramic (15) are rectangular structures, the negative electrodes are complete rectangular electrodes, and the positive electrodes are evenly divided into four rectangular blocks; the negative electrode of the first piezoelectric ceramic (13) is directly adhered to the two sides of the first stator matrix (143); the negative electrode of the second piezoelectric ceramic (15) is directly adhered to the two sides of the second stator matrix (144); the first stator matrix (143) and the second stator matrix (144) generate elliptical motion through diagonal excitation; The first sensor (6) and the second sensor (12) are respectively fixed on the first bracket (141) and the second bracket (142), and are used to measure the rotation speed of the first rotor (5) and the second rotor (11).

2. The piezoelectric driven two-degree-of-freedom pointing mechanism according to claim 1, characterized in that: The piezoelectric ceramic (13) is caused to vibrate by the inverse piezoelectric effect using a single-phase electrical excitation method, and simultaneously excites the first stator base (143) to form the same vibration, thereby causing the driving foot (147) to generate standing wave motion and drive the first rotor (5) to rotate.

3. The piezoelectric driven two-degree-of-freedom pointing mechanism according to claim 1, characterized in that: The first stator matrix (143) and the second stator matrix (144) are combined with the second piezoelectric ceramic (15) and the first piezoelectric ceramic (13) to form two piezoelectric stators, and the piezoelectric stators are driven by a composite mode of first-order longitudinal vibration and second-order bending vibration.

4. The piezoelectric driven two-degree-of-freedom pointing mechanism according to claim 1, characterized in that: The end of the third bearing (51) is fixed with a flange or bolts.

5. The piezoelectric driven two-degree-of-freedom pointing mechanism according to claim 1, characterized in that: Both sides of the first pressing plate (2) and the second pressing plate (8) are connecting surfaces (25), four second bolt holes (21) are provided on the connecting surfaces (25), and an inner boss (22) is provided between the first pressing plate (2) and the second pressing plate (8); a circular through hole is provided in the center of the first pressing plate (2) and the second pressing plate (8), a circle of circular bosses is provided on the inner side of the bottom of the circular through hole, the surface of the circular boss is the bearing side contact surface (23), and the side wall of the circular through hole is the bearing outer ring contact surface (24); The bearing outer ring contact surface (24) contacts the outer ring surface of the first bearing (4), and the two are interference fit; the bearing side contact surface (24) contacts the outer ring plane of the first bearing (4) for limiting position; the first pressure plate (2) is fixed in the second fixing groove (149), and is limited by the inner side boss (22) and the connecting surface (25); the first fixing bolt (3) cooperates with the second bolt hole (21) and the threaded hole on the second fixing groove (149) to tighten the first pressure plate (2); The bearing outer ring contact surface (24) contacts the outer ring surface of the second bearing (10), and the two are interference fit; the bearing side contact surface (23) contacts the outer ring plane of the second bearing (10) for limiting position; the second pressure plate (8) is fixed in the second fixing groove (149), and is limited by the inner side boss (22) and the connecting surface (25); the second fixing bolt (9) cooperates with the second bolt hole (21) and the threaded hole on the second fixing groove (149) to tighten the second pressure plate (8).

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