A spherical multi-degree-of-freedom piezoelectric actuating mechanism and a driving method thereof

Abstract

The application discloses a spherical multi-degree-of-freedom piezoelectric actuating mechanism and a driving method thereof. The spherical piezoelectric actuating mechanism comprises a spherical vibrator, a rotor, a fixed base and a pre-tightening assembly. The vibrator comprises a piezoelectric vibrator base, a driving foot and a piezoelectric ceramic sheet. The rotor is composed of two half-spherical shells and is combined by the pre-tightening assembly to form a spherical structure and is wrapped on the piezoelectric vibrator. The fixed base is fixed by clamping a special position of the vibrator and is located on the other side away from the rotor. The vibrator drives the rotor composed of the two half-spherical shells through friction to output torque outward, and the direction of rotation can be changed by changing the excitation direction. The application has the advantages of less components, multi-degree-of-freedom movement, compact structure and the like.

Description

Technical Field

[0001] This invention relates to the field of robotics, and specifically to a spherical multi-degree-of-freedom piezoelectric actuator and its driving method. Background Technology

[0002] Traditional multi-degree-of-freedom (DOF) actuators typically employ multiple actuators in conjunction with complex transmission structures to achieve their purpose. This results in relatively large sizes, making miniaturization and high integration difficult. Existing technologies cannot meet the high precision and high integration requirements of the aerospace and robotics fields. Summary of the Invention

[0003] Purpose of the invention: This invention provides a structural design and driving method for a spherical multi-degree-of-freedom piezoelectric actuator, which solves the problems of large size and difficulty in miniaturization and high integration.

[0004] Technical Solution: This invention proposes a spherical multi-degree-of-freedom piezoelectric actuation mechanism, comprising a spherical rotor, a piezoelectric vibrator located inside the spherical rotor, and a fixed base connected to the piezoelectric vibrator; the spherical rotor includes a first hemispherical shell and a second hemispherical shell, which are fixedly connected by a pre-tightening assembly, forming a hollow spherical shell with a pre-reserved opening at the bottom; the piezoelectric vibrator includes several vibrating rings, several driving feet, and several piezoelectric ceramic plates, with driving feet on both sides of the diameter of each vibrating ring; the vibrating rings include a first vibrating ring, a second vibrating ring, and a third vibrating ring, which are orthogonal to each other; each of the first, second, and third vibrating rings includes a first end face, a second end face, and an outer wall; the driving feet are fixedly connected to the outer wall of the vibrating rings; the several ceramic plates are evenly distributed on the first and second end faces of the first, second, and third vibrating rings; the fixed base passes through the pre-reserved opening at the bottom of the first and second hemispherical shells to clamp the vibrating rings and fix the piezoelectric vibrator.

[0005] Preferably, the first, second, and third vibrating rings have the same shape, all being thin circular rings.

[0006] Preferably, the piezoelectric vibrator is formed by three thin, circular vibrating rings orthogonally forming a spherical cage shape.

[0007] Preferably, the first, second, and third vibration rings further include inner sidewalls, which are annular with the outer sidewalls and have the same axis.

[0008] Preferably, the fixed base includes a first fixed arm, a second fixed arm, and a base disc; the base disc is provided with a first fixed arm and a second fixed arm, and the first fixed arm and the second fixed arm clamp the first end face and the second end face of the vibration ring to fix the vibration ring.

[0009] Preferably, the pre-tightening assembly includes an adjusting bolt and a pre-tightening spring. The adjusting bolt includes a nut, a light post, and a stud, and the pre-tightening spring is sleeved on the light post.

[0010] Preferably, the upper and side wings of the outer wall of the first hemispherical shell are provided with countersunk holes, and the upper and side wings of the outer wall of the second hemispherical shell are provided with threaded holes corresponding to the countersunk holes; one end of the preload spring contacts the nut, and the other end contacts the countersunk hole on the first hemispherical shell; the adjusting bolt passes through the countersunk hole on the first hemispherical shell and is connected to the threaded hole on the second hemispherical shell; the sides of the first and second hemispherical shells abut against each other through the adjusting bolt and the preload spring.

[0011] Preferably, the piezoelectric ceramic sheet comprises forty-eight piezoelectric ceramic sheets, all of which are polarized along the thickness direction and have the same polarization direction.

[0012] Preferably, the first vibrating ring is formed by the intersection of the second and third vibrating rings, creating four arc-shaped segments. A first piezoelectric ceramic sheet, a second piezoelectric ceramic sheet, a third piezoelectric ceramic sheet, a fourth piezoelectric ceramic sheet, a fifth piezoelectric ceramic sheet, a sixth piezoelectric ceramic sheet, a seventh piezoelectric ceramic sheet, and an eighth piezoelectric ceramic sheet are evenly distributed along the circumference of the first end face of the first vibrating ring. The first and second piezoelectric ceramic sheets are located on the first arc-shaped segment, the third and fourth piezoelectric ceramic sheets are located on the second arc-shaped segment, the fifth and sixth piezoelectric ceramic sheets are located on the third arc-shaped segment, and the seventh and eighth piezoelectric ceramic sheets are located on the fourth arc-shaped segment. Located on the fourth arc segment; the ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, and sixteenth piezoelectric ceramic sheets are evenly distributed along the circumference of the second end face of the first vibrating ring, wherein the ninth and tenth piezoelectric ceramic sheets are located on the first arc segment, the eleventh and twelfth piezoelectric ceramic sheets are located on the second arc segment, the thirteenth and fourteenth piezoelectric ceramic sheets are located on the third arc segment, and the fifteenth and sixteenth piezoelectric ceramic sheets are located on the fourth arc segment;

[0013] The second vibrating ring is formed by the intersection of the first and third vibrating rings, creating four arc-shaped segments. The first end face of the second vibrating ring is uniformly distributed with seventeenth, eighteenth, nineteenth, twentieth, twenty-first, twenty-second, twenty-third, and twenty-fourth piezoelectric ceramic sheets along its circumference. The seventeenth and eighteenth piezoelectric ceramic sheets are located on the first arc-shaped segment, the nineteenth and twentieth piezoelectric ceramic sheets on the second arc-shaped segment, the twenty-first and twenty-second piezoelectric ceramic sheets on the third arc-shaped segment, and the twenty-third and twenty-fourth piezoelectric ceramic sheets on the second arc-shaped segment. The piezoelectric ceramic sheet is located on the fourth arc segment; the second end face of the second vibrating ring is uniformly distributed along the circumference of the second end face with the following piezoelectric ceramic sheets: the twenty-fifth piezoelectric ceramic sheet, the twenty-sixth piezoelectric ceramic sheet, the twenty-seventh piezoelectric ceramic sheet, the twenty-eighth piezoelectric ceramic sheet, the twenty-ninth piezoelectric ceramic sheet, the thirtieth piezoelectric ceramic sheet, the thirty-first piezoelectric ceramic sheet, and the thirty-second piezoelectric ceramic sheet, wherein the twenty-fifth and twenty-sixth piezoelectric ceramic sheets are located on the first arc segment, the twenty-seventh and twenty-eighth piezoelectric ceramic sheets are located on the second arc segment, the twenty-ninth and thirtieth piezoelectric ceramic sheets are located on the third arc segment, and the thirty-first and thirty-second piezoelectric ceramic sheets are located on the fourth arc segment;

[0014] The third vibrating ring is formed by the intersection of the first and second vibrating rings, creating four arc-shaped segments. Along the circumference of the first end face of the third vibrating ring, piezoelectric ceramic sheets numbered thirty-third, thirty-fourth, thirty-fifth, thirty-sixth, thirty-seventh, thirty-eighth, thirty-ninth, and fortieth are evenly distributed sequentially. The thirty-third and thirty-fourth piezoelectric ceramic sheets are located on the first arc-shaped segment, the thirty-fifth and thirty-sixth piezoelectric ceramic sheets are located on the second arc-shaped segment, the thirty-seventh and thirty-eighth piezoelectric ceramic sheets are located on the third arc-shaped segment, and the thirty-ninth and fortieth piezoelectric ceramic sheets are located on the fourth arc-shaped segment. Above; on the second end face of the third vibration ring, piezoelectric ceramic sheets numbered forty-first, forty-second, forty-third, forty-fourth, forty-fifth, forty-sixth, forty-seventh, and forty-eighth are evenly distributed along the circumference of the second end face. Among them, the forty-first and forty-second piezoelectric ceramic sheets are located on the first arc segment, the forty-third and forty-fourth piezoelectric ceramic sheets are located on the second arc segment, the forty-fifth and forty-sixth piezoelectric ceramic sheets are located on the third arc segment, and the forty-seventh and forty-eighth piezoelectric ceramic sheets are located on the fourth arc segment.

[0015] A driving method for a spherical multi-degree-of-freedom piezoelectric actuator includes the following steps: applying a first-phase driving voltage to the first, second, fourth, seventh, eleventh, thirteenth, fourteenth, and sixteenth piezoelectric ceramic plates; applying a second-phase driving voltage to the third, fifth, sixth, eighth, ninth, tenth, twelfth, and fifteenth piezoelectric ceramic plates, causing the spherical rotor to rotate in a first direction; applying a first-phase driving voltage to the seventeenth, eighteenth, twentieth, twenty-third, twenty-seventh, twenty-ninth, thirtieth, and thirty-second piezoelectric ceramic plates; and applying a second-phase driving voltage to the nineteenth piezoelectric ceramic plate. A second-phase driving voltage is applied to the 21st, 22nd, 24th, 25th, 26th, 28th, and 31st piezoelectric ceramic sheets, causing the spherical rotor to rotate in a second direction; a first-phase driving voltage is applied to the 33rd, 34th, 36th, 39th, 43rd, 45th, 46th, and 48th piezoelectric ceramic sheets, and a second-phase driving voltage is applied to the 35th, 37th, 38th, 40th, 41st, 42nd, 44th, and 47th piezoelectric ceramic sheets, causing the spherical rotor to rotate in a third direction;

[0016] Adjusting the first-phase drive voltage and the second-phase drive voltage to make the phase difference π / 2 causes the piezoelectric vibrator to generate orthogonal radial stretching vibration and axial bending vibration, causing the drive foot end point to make elliptical motion, which drives the first hemisphere and the second hemisphere to rotate under the action of friction. If it is necessary to drive the first hemisphere and the second hemisphere to rotate in opposite directions, adjust the first-phase drive voltage and the second-phase drive voltage to make the phase difference -π / 2.

[0017] Beneficial effects: 1. The actuation principle of the actuation mechanism proposed in this invention is piezoelectric drive technology, which adopts symmetrical multi-leg drive, improves the overall continuity of actuation, and at the same time improves the motion resolution during actuation;

[0018] 2. The actuation mechanism proposed in this invention can drive the rotor to rotate in multiple directions using only one piezoelectric vibrator unit. Due to the reduction of actuation units, the structure of this actuation device is more compact. Attached Figure Description

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

[0020] Figure 2 This is an exploded view of the structure of the present invention;

[0021] Figure 3 This is a schematic diagram of the fixed base structure of the present invention;

[0022] Figure 4 This is a schematic diagram of the piezoelectric oscillator structure of the present invention;

[0023] Figure 5 These are schematic diagrams of the first to sixteenth piezoelectric ceramic sheets of the present invention;

[0024] Figure 6 These are schematic diagrams of the seventeenth to thirty-second piezoelectric ceramic sheets of the present invention;

[0025] Figure 7 These are schematic diagrams of the thirty-third to forty-eighth piezoelectric ceramic sheets of the present invention;

[0026] Figure 8 This is a schematic diagram of the first hemispherical shell structure of the present invention;

[0027] Figure 9 This is a schematic diagram of the second hemispherical shell structure of the present invention;

[0028] Figure 10 This is a schematic diagram of the structure of the adjusting bolt of the present invention;

[0029] Figure 11 This is a schematic diagram of the radial vibration modes of the piezoelectric vibrator of the present invention;

[0030] Figure 12 This is a schematic diagram of the axial vibration modes of the piezoelectric vibrator of the present invention. Detailed Implementation

[0031] according to Figures 1 to 12 This invention discloses a spherical multi-degree-of-freedom piezoelectric actuator and its driving method, such as... Figure 1 and Figure 2 As shown, the spherical multi-degree-of-freedom piezoelectric actuator includes a piezoelectric oscillator 4, a spherical rotor 1, a preload assembly, and a fixed base 2. Figure 4As shown, the piezoelectric vibrator 4 includes a first vibrating ring 10, a second vibrating ring 11, a third vibrating ring 12, a driving foot 13, and first to forty-eight piezoelectric ceramic sheets. The first vibrating ring 10, the second vibrating ring 11, and the third vibrating ring 12 are all thin circular rings with the same shape. Each ring includes a first end face, a second end face, an inner side wall, and an outer side wall. The inner side wall and the outer side wall are both circular and have the same axis. The driving foot 13 is a cylinder. One end of the first and fourth driving feet is fixed to the outer side wall of the first vibrating ring, one end of the second and fifth driving feet is fixed to the outer side wall of the second vibrating ring, and one end of the third and sixth driving feet is fixed to the outer side wall of the third vibrating ring. The first and fourth driving feet are located on both sides of the diameter of the first vibrating ring, the second and fifth driving feet are located on both sides of the diameter of the second vibrating ring, and the third and sixth driving feet are located on both sides of the diameter of the third vibrating ring. The first to forty-eight piezoelectric ceramic sheets are all polarized along the thickness direction, and the polarization directions are the same.

[0032] The first vibrating ring 10, the second vibrating ring 11, and the third vibrating ring 12 are orthogonal to each other, and the piezoelectric vibrator 4 is a spherical cage composed of three orthogonal thin circular rings.

[0033] like Figure 5 As shown, a first piezoelectric ceramic sheet 14, a second piezoelectric ceramic sheet 15, a third piezoelectric ceramic sheet 16, a fourth piezoelectric ceramic sheet 17, a fifth piezoelectric ceramic sheet 18, a sixth piezoelectric ceramic sheet 19, a seventh piezoelectric ceramic sheet 20, and an eighth piezoelectric ceramic sheet 21 are uniformly distributed on the first end face of the first vibrating ring 10. A ninth piezoelectric ceramic sheet 22, a tenth piezoelectric ceramic sheet 23, an eleventh piezoelectric ceramic sheet 24, a twelfth piezoelectric ceramic sheet 25, a thirteenth piezoelectric ceramic sheet 26, a fourteenth piezoelectric ceramic sheet 27, a fifteenth piezoelectric ceramic sheet 28, and a sixteenth piezoelectric ceramic sheet 29 are uniformly distributed on the second end face of the first vibrating ring 10.

[0034] like Figure 6 As shown, the seventeenth piezoelectric ceramic sheet 30, the eighteenth piezoelectric ceramic sheet 31, the nineteenth piezoelectric ceramic sheet 32, the twentieth piezoelectric ceramic sheet 33, the twenty-first piezoelectric ceramic sheet 34, the twenty-second piezoelectric ceramic sheet 35, the twenty-third piezoelectric ceramic sheet 36, and the twenty-fourth piezoelectric ceramic sheet 37 are evenly distributed on the first end face of the second vibration ring 11. The twenty-fifth piezoelectric ceramic sheet 38, the twenty-sixth piezoelectric ceramic sheet 39, the twenty-seventh piezoelectric ceramic sheet 40, the twenty-eighth piezoelectric ceramic sheet 41, the twenty-ninth piezoelectric ceramic sheet 42, the thirtieth piezoelectric ceramic sheet 43, the thirty-first piezoelectric ceramic sheet 44, and the thirty-second piezoelectric ceramic sheet 45 are evenly distributed on the second end face of the second vibration ring 11.

[0035] like Figure 7As shown, the third vibrating ring 12 has a piezoelectric ceramic sheet 46, 47, 48, 49, 50, 51, 52 and 53 evenly distributed on its first end face, and a piezoelectric ceramic sheet 54, 55, 56, 57, 58, 59, 60 and 61 evenly distributed on its second end face.

[0036] like Figure 8 , Figure 9 As shown, the spherical rotor 1 is composed of a first hemispherical shell 5 and a second hemispherical shell 3. Both the first hemispherical shell 5 and the second hemispherical shell 3 include an outer wall, an inner wall, a side surface and a lower surface. The hollow spherical shell composed of the first hemispherical shell 5 and the second hemispherical shell 3 has an opening at the bottom. The outer wall of the first hemispherical shell 5 is provided with a countersunk hole 62, and the second hemispherical shell 3 is provided with a corresponding threaded hole 63.

[0037] The pre-tightening assembly includes pre-tightening elements that correspond one-to-one with the countersunk holes 62 on the outer wall of the first hemisphere and the threaded holes 63 on the outer wall of the second hemisphere. The pre-tightening elements include an adjusting bolt 67 and a pre-tightening spring 6. The adjusting bolt 67 includes a nut 66, a post 65, and a stud 64. The pre-tightening spring 6 is sleeved on the post 65, with one end of the pre-tightening spring 6 in contact with the nut 66 and the other end in contact with the countersunk holes 62 on the first hemisphere 5. The adjusting bolt 67 passes through the countersunk holes 62 on the first hemisphere 5 and is connected to the threaded holes 63 on the second hemisphere 3. The sides of the first hemisphere 5 and the second hemisphere 3 abut against each other through the adjusting bolt 67 and the pre-tightening spring 6.

[0038] The fixed base 2 includes a first fixed arm 7, a second fixed arm 8 and a base disk 9; the base disk 9 is provided with the first fixed arm 7 and the second fixed arm 8; the first fixed arm 7 and the second fixed arm 8 are clamped on the first and second end faces of the vibration ring of the piezoelectric vibrator 4 to fix the piezoelectric vibrator 4.

[0039] The present invention also discloses a driving method for the spherical multi-degree-of-freedom piezoelectric actuator, comprising the following steps:

[0040] A first-phase driving voltage is applied to the first piezoelectric ceramic sheet 14, the second piezoelectric ceramic sheet 15, the fourth piezoelectric ceramic sheet 17, the seventh piezoelectric ceramic sheet 20, the eleventh piezoelectric ceramic sheet 24, the thirteenth piezoelectric ceramic sheet 26, the fourteenth piezoelectric ceramic sheet 27, and the sixteenth piezoelectric ceramic sheet 29. A first-phase driving voltage is applied to the third piezoelectric ceramic sheet 16, the fifth piezoelectric ceramic sheet 18, the sixth piezoelectric ceramic sheet 19, the eighth piezoelectric ceramic sheet 21, the ninth piezoelectric ceramic sheet 22, the tenth piezoelectric ceramic sheet 23, and the twelfth piezoelectric ceramic sheet. 25. A second-phase driving voltage is applied to the fifteenth piezoelectric ceramic plate 28, causing the spherical rotor 1 to rotate in the first direction; a first-phase driving voltage is applied to the seventeenth piezoelectric ceramic plate 30, the eighteenth piezoelectric ceramic plate 31, the twentieth piezoelectric ceramic plate 33, the twenty-third piezoelectric ceramic plate 36, the twenty-seventh piezoelectric ceramic plate 40, the twenty-ninth piezoelectric ceramic plate 42, the thirtieth piezoelectric ceramic plate 43, and the thirty-second piezoelectric ceramic plate 45, and a first-phase driving voltage is applied to the nineteenth piezoelectric ceramic plate 32 and the twenty-first piezoelectric ceramic plate 36. 4. A second-phase driving voltage is applied to the 22nd piezoelectric ceramic sheet 35, the 24th piezoelectric ceramic sheet 37, the 25th piezoelectric ceramic sheet 38, the 26th piezoelectric ceramic sheet 39, the 28th piezoelectric ceramic sheet 41, and the 31st piezoelectric ceramic sheet 44, causing the spherical rotor 1 to rotate in a second direction; a first-phase driving voltage is applied to the 33rd piezoelectric ceramic sheet 46, the 34th piezoelectric ceramic sheet 47, the 36th piezoelectric ceramic sheet 49, the 39th piezoelectric ceramic sheet 52, the 43rd piezoelectric ceramic sheet 56, the 45th piezoelectric ceramic sheet 58, the 46th piezoelectric ceramic sheet 59, and the 48th piezoelectric ceramic sheet 61, and a second-phase driving voltage is applied to the 35th piezoelectric ceramic sheet 48, the 37th piezoelectric ceramic sheet 50, the 38th piezoelectric ceramic sheet 51, the 40th piezoelectric ceramic sheet 53, the 41st piezoelectric ceramic sheet 54, the 42nd piezoelectric ceramic sheet 55, the 44th piezoelectric ceramic sheet 57, and the 47th piezoelectric ceramic sheet 60, causing the spherical rotor 1 to rotate in a third direction;

[0041] Adjusting the first-phase drive voltage and the second-phase drive voltage to make their phase difference π / 2 causes the piezoelectric vibrator 4 to generate orthogonal radial stretching vibration and axial bending vibration, causing the endpoint of the drive foot 13 to make elliptical motion, which drives the first hemispherical shell 5 and the second hemispherical shell 3 to rotate under the action of friction. If it is necessary to drive the first hemispherical shell 5 and the second hemispherical shell 3 to rotate in opposite directions, adjust the first-phase drive voltage and the second-phase drive voltage to make their phase difference -π / 2.

Claims

1. A spherical multi-degree-of-freedom piezoelectric actuator, characterized in that, The system includes a spherical rotor (1), a piezoelectric vibrator (4) located inside the spherical rotor (1), and a fixed base (2) connected to the piezoelectric vibrator (4); the spherical rotor (1) includes a first hemispherical shell (5) and a second hemispherical shell (3), the first hemispherical shell (5) and the second hemispherical shell (3) are fixedly connected by a pre-tightening assembly, the first hemispherical shell (5) and the second hemispherical shell (3) form a hollow spherical shell with a pre-reserved opening at the bottom; the piezoelectric vibrator (4) includes several vibrating rings, several driving feet (13) and several piezoelectric ceramic plates, the vibrating rings are provided with driving feet (13) on both sides of the diameter, the vibrating rings include a first vibrating ring (10) and a second vibrating ring (11) The first vibration ring (10), the second vibration ring (11), and the third vibration ring (12) are orthogonal to each other. The first vibration ring (10), the second vibration ring (11), and the third vibration ring (12) each include a first end face, a second end face, and an outer side wall. The driving foot (13) is fixedly connected to the outer side wall of the vibration ring. The several ceramic pieces are evenly distributed on the first end face and the second end face of the first vibration ring (10), the second vibration ring (11), and the third vibration ring (12). The fixed base (2) passes through the reserved hole below the first hemispherical shell (5) and the second hemispherical shell (3) to clamp the vibration ring and fix the piezoelectric vibrator (4). The first vibrating ring (10), the second vibrating ring (11), and the third vibrating ring (12) have the same shape, all being thin circular rings. The piezoelectric vibrator (4) is formed by three thin circular ring vibrating rings orthogonally forming a spherical cage. The first vibrating ring (10), the second vibrating ring (11), and the third vibrating ring (12) also include inner sidewalls, which are circular with the outer sidewalls and have the same axis. The fixed base (2) includes a first fixed arm (7), a second fixed arm (8), and a base disc (9). The base disc (9) is provided with the first fixed arm (7) and the second fixed arm (8), which clamp the first and second end faces of the vibrating rings to fix them. The pre-tightening assembly includes an adjusting bolt (67) and a pre-tightening spring (6). The adjusting bolt includes a nut (66), a light post (65), and a stud (64). The preload spring (6) is sleeved on the light post (65). The upper and side wings of the outer wall of the first hemispherical shell (5) are provided with countersunk holes (62), and the upper and side wings of the outer wall of the second hemispherical shell (3) are provided with threaded holes (63) corresponding to the countersunk holes (62). One end of the preload spring (6) is in contact with the nut (66), and the other end is in contact with the countersunk hole (62) on the first hemispherical shell (5). The adjusting bolt (67) passes through the countersunk hole (62) on the first hemispherical shell (5) and is connected to the threaded hole (63) on the second hemispherical shell (3). The sides of the first hemispherical shell (5) and the second hemispherical shell (3) abut against each other through the adjusting bolt (67) and the preload spring (6).

2. The spherical multi-degree-of-freedom piezoelectric actuator according to claim 1, characterized in that, The piezoelectric ceramic sheet comprises forty-eight piezoelectric ceramic sheets, all of which are polarized along the thickness direction and have the same polarization direction.

3. The spherical multi-degree-of-freedom piezoelectric actuator according to claim 2, characterized in that, The first vibrating ring (10) is formed by the intersection of the second vibrating ring (11) and the third vibrating ring (12) into four arc-shaped segments. The first vibrating ring (10) has a first piezoelectric ceramic sheet (14), a second piezoelectric ceramic sheet (15), a third piezoelectric ceramic sheet (16), a fourth piezoelectric ceramic sheet (17), a fifth piezoelectric ceramic sheet (18), a sixth piezoelectric ceramic sheet (19), a seventh piezoelectric ceramic sheet (20), and an eighth piezoelectric ceramic sheet (21) evenly distributed along the circumference of the first end face. The first piezoelectric ceramic sheet (14) and the second piezoelectric ceramic sheet (15) are located on the first arc-shaped segment, the third piezoelectric ceramic sheet (16) and the fourth piezoelectric ceramic sheet (17) are located on the second arc-shaped segment, the fifth piezoelectric ceramic sheet (18) and the sixth piezoelectric ceramic sheet (19) are located on the third arc-shaped segment, and the seventh piezoelectric ceramic sheet (20) and the eighth piezoelectric ceramic sheet (21) are located on the third arc-shaped segment. (21) Located on the fourth arc segment; The ninth piezoelectric ceramic sheet (22), the tenth piezoelectric ceramic sheet (23), the eleventh piezoelectric ceramic sheet (24), the twelfth piezoelectric ceramic sheet (25), the thirteenth piezoelectric ceramic sheet (26), the fourteenth piezoelectric ceramic sheet (27), the fifteenth piezoelectric ceramic sheet (28) and the sixteenth piezoelectric ceramic sheet (29) are evenly distributed along the circumference of the second end face of the first vibration ring (10), wherein the ninth piezoelectric ceramic sheet (22) and the tenth piezoelectric ceramic sheet (23) are located on the first arc segment, the eleventh piezoelectric ceramic sheet (24) and the twelfth piezoelectric ceramic sheet (25) are located on the second arc segment, the thirteenth piezoelectric ceramic sheet (26) and the fourteenth piezoelectric ceramic sheet (27) are located on the third arc segment, and the fifteenth piezoelectric ceramic sheet (28) and the sixteenth piezoelectric ceramic sheet (29) are located on the fourth arc segment; The second vibrating ring (11) is formed by the intersection of the first vibrating ring (10) and the third vibrating ring (12) into four arc-shaped segments. The first end face of the second vibrating ring (11) is uniformly distributed with the seventeenth piezoelectric ceramic sheet (30), the eighteenth piezoelectric ceramic sheet (31), the nineteenth piezoelectric ceramic sheet (32), the twentieth piezoelectric ceramic sheet (33), the twenty-first piezoelectric ceramic sheet (34), the twenty-second piezoelectric ceramic sheet (35), the twenty-third piezoelectric ceramic sheet (36), and the twenty-fourth piezoelectric ceramic sheet (37) along the circumference of the first end face. The seventeenth piezoelectric ceramic sheet (30) and the eighteenth piezoelectric ceramic sheet (31) are located on the first arc-shaped segment; the nineteenth piezoelectric ceramic sheet (32) and the twentieth piezoelectric ceramic sheet (33) are located on the second arc-shaped segment; the twenty-first piezoelectric ceramic sheet (34) and the twenty-second piezoelectric ceramic sheet (35) are located on the third arc-shaped segment; and the twenty-third piezoelectric ceramic sheet (36) and the twenty-fourth piezoelectric ceramic sheet (37) are located on the second arc-shaped segment. The ceramic sheet (37) is located on the fourth arc segment; the second end face of the second vibration ring (11) is uniformly distributed along the circumference of the second end face with the twenty-fifth piezoelectric ceramic sheet (38), the twenty-sixth piezoelectric ceramic sheet (39), the twenty-seventh piezoelectric ceramic sheet (40), the twenty-eighth piezoelectric ceramic sheet (41), the twenty-ninth piezoelectric ceramic sheet (42), the thirtieth piezoelectric ceramic sheet (43), the thirty-first piezoelectric ceramic sheet (44) and the thirty-second piezoelectric ceramic sheet (45), of which the twenty-fifth piezoelectric ceramic sheet (38) and the twenty-sixth piezoelectric ceramic sheet (39) are located on the first arc segment, the twenty-seventh piezoelectric ceramic sheet (40) and the twenty-eighth piezoelectric ceramic sheet (41) are located on the second arc segment, the twenty-ninth piezoelectric ceramic sheet (42) and the thirtieth piezoelectric ceramic sheet (43) are located on the third arc segment, and the thirty-first piezoelectric ceramic sheet (44) and the thirty-second piezoelectric ceramic sheet (45) are located on the fourth arc segment; The third vibrating ring (12) is formed by the intersection of the first vibrating ring (10) and the second vibrating ring (11) into four arc-shaped segments. The third vibrating ring (12) has a 33rd piezoelectric ceramic sheet (46), a 34th piezoelectric ceramic sheet (47), a 35th piezoelectric ceramic sheet (48), a 36th piezoelectric ceramic sheet (49), a 37th piezoelectric ceramic sheet (50), a 38th piezoelectric ceramic sheet (51), a 39th piezoelectric ceramic sheet (52), and a 40th piezoelectric ceramic sheet (53) evenly distributed along the circumference of the first end face. The 33rd piezoelectric ceramic sheet (46) and the 34th piezoelectric ceramic sheet (47) are located on the first arc-shaped segment, the 35th piezoelectric ceramic sheet (48) and the 36th piezoelectric ceramic sheet (49) are located on the second arc-shaped segment, the 37th piezoelectric ceramic sheet (50) and the 38th piezoelectric ceramic sheet (51) are located on the third arc-shaped segment, and the 39th piezoelectric ceramic sheet (52) and the 40th piezoelectric ceramic sheet (53) are located on the fourth arc-shaped segment. On the second end face of the third vibration ring (12), piezoelectric ceramic sheets 41 (54), 42 (55), 43 (56), 44 (57), 45 (58), 46 (59), 47 (60), and 48 (61) are evenly distributed along the circumference of the second end face. Among them, piezoelectric ceramic sheets 41 (54) and 42 (55) are located on the first arc segment, piezoelectric ceramic sheets 43 (56) and 44 (57) are located on the second arc segment, piezoelectric ceramic sheets 45 (58) and 46 (59) are located on the third arc segment, and piezoelectric ceramic sheets 47 (60) and 48 (61) are located on the fourth arc segment.

4. A driving method for a spherical multi-degree-of-freedom piezoelectric actuator according to claim 3, characterized in that, Includes the following steps: A first-phase driving voltage is applied to the first piezoelectric ceramic sheet (14), the second piezoelectric ceramic sheet (15), the fourth piezoelectric ceramic sheet (17), the seventh piezoelectric ceramic sheet (20), the eleventh piezoelectric ceramic sheet (24), the thirteenth piezoelectric ceramic sheet (26), the fourteenth piezoelectric ceramic sheet (27), and the sixteenth piezoelectric ceramic sheet (29). A first-phase driving voltage is applied to the third piezoelectric ceramic sheet (16), the fifth piezoelectric ceramic sheet (18), the sixth piezoelectric ceramic sheet (19), the eighth piezoelectric ceramic sheet (21), the ninth piezoelectric ceramic sheet (22), the tenth piezoelectric ceramic sheet (23), and the twelfth piezoelectric ceramic sheet (29). A second-phase driving voltage is applied to ceramic plate (25) and the fifteenth piezoelectric ceramic plate (28) to cause the spherical rotor (1) to rotate in the first direction; a first-phase driving voltage is applied to the seventeenth piezoelectric ceramic plate (30), the eighteenth piezoelectric ceramic plate (31), the twentieth piezoelectric ceramic plate (33), the twenty-third piezoelectric ceramic plate (36), the twenty-seventh piezoelectric ceramic plate (40), the twenty-ninth piezoelectric ceramic plate (42), the thirtieth piezoelectric ceramic plate (43), and the thirty-second piezoelectric ceramic plate (45), and a second-phase driving voltage is applied to the nineteenth piezoelectric ceramic plate (32) and the twenty-first piezoelectric ceramic plate (28). (34), the 22nd piezoelectric ceramic sheet (35), the 24th piezoelectric ceramic sheet (37), the 25th piezoelectric ceramic sheet (38), the 26th piezoelectric ceramic sheet (39), the 28th piezoelectric ceramic sheet (41), and the 31st piezoelectric ceramic sheet (44) are subjected to a second phase driving voltage, causing the spherical rotor (1) to rotate in a second direction; the 33rd piezoelectric ceramic sheet (46), the 34th piezoelectric ceramic sheet (47), the 36th piezoelectric ceramic sheet (49), the 39th piezoelectric ceramic sheet (52), the 43rd piezoelectric ceramic sheet (56), and the 35th piezoelectric ceramic sheet (44) are subjected to a second phase driving voltage, causing the spherical rotor (1) to rotate in a second direction; the 33rd piezoelectric ceramic sheet (46), the 34th piezoelectric ceramic sheet (47), the 36th piezoelectric ceramic sheet (49), the 39th piezoelectric ceramic sheet (52), and the 43rd piezoelectric ceramic sheet (56) are subjected to a second phase driving voltage, causing the spherical rotor (1) to rotate in a second direction; the 35th ...5th piezoelectric ceramic sheet (47), the 36th piezoelectric ceramic sheet (49), the 39th piezoelectric ceramic sheet (52), and the 43rd piezo The first phase driving voltage is applied to the forty-fifth piezoelectric ceramic sheet (58), the forty-sixth piezoelectric ceramic sheet (59), and the forty-eighth piezoelectric ceramic sheet (61), and the second phase driving voltage is applied to the thirty-fifth piezoelectric ceramic sheet (48), the thirty-seventh piezoelectric ceramic sheet (50), the thirty-eighth piezoelectric ceramic sheet (51), the fortieth piezoelectric ceramic sheet (53), the forty-first piezoelectric ceramic sheet (54), the forty-second piezoelectric ceramic sheet (55), the forty-fourth piezoelectric ceramic sheet (57), and the forty-seventh piezoelectric ceramic sheet (60), so that the spherical rotor (1) will rotate in the third direction; Adjusting the first phase driving voltage and the second phase driving voltage to make the phase difference π / 2, the piezoelectric vibrator (4) generates orthogonal radial stretching vibration and axial bending vibration, causing the end point of the driving foot (13) to make elliptical motion, and under the action of friction, driving the first hemispherical shell (5) and the second hemispherical shell (3) to rotate. If it is necessary to drive the first hemispherical shell (5) and the second hemispherical shell (3) to rotate in opposite directions, adjust the first phase driving voltage and the second phase driving voltage so that the phase difference is -π / 2.

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