Parasitic inertia type piezoelectric actuator for realizing low frequency and high speed

Abstract

The invention relates to a parasitic inertia type piezoelectric actuator capable of realizing low frequency and high speed, and solves the technical problem that the parasitic inertia type piezoelectric actuator cannot realize high-speed motion during low-frequency signal driving. The actuator mainly comprises a piezoelectric stack, a two-stage lever flexible hinge mechanism and a movable guide rail. The two piezoelectric stacks are simultaneously electrified and driven, the displacement is doubled through a secondary lever and a Z-shaped beam in the secondary lever flexible hinge mechanism, and the unit step length of the driver is increased, so that the unit speed is greatly increased, and the low-frequency and high-speed target is realized; the two-stage lever flexible hinge mechanism is high in rigidity and can bear a large load, the rigidity of the piezoelectric stack in the main output direction is also fully utilized, and the output load of the driver is improved. The driver is simple in structure and can be applied to the fields of micro-operation robots and the like.

Description

Technical Field

[0001] The present invention relates to the fields of precision and ultra-precision machining, micro-nano operating robots and micro-electromechanical systems, and in particular to a parasitic inertia type piezoelectric driver that realizes low frequency and high speed. Background Art

[0002] As a new type of precision driving method, piezoelectric drive technology has been widely used in aerospace, semiconductor manufacturing, micro-nano processing, medical science fields due to its multiple outstanding advantages such as high precision, fast response, no electromagnetic interference, and good controllability, and has achieved many results.

[0003] According to their working principles, piezoelectric actuators can be roughly divided into four types: direct-acting type, ultrasonic type, bionic type, and stick-slip type. Among them, stick-slip piezoelectric actuators can be divided into parasitic inertia type and constant force contact type according to whether the contact force changes. Piezoelectric ultrasonic actuators often use the phase coupling of the excitation signal and use the resonance of the piezoelectric element to excite the stator to produce an elliptical trajectory, thereby driving the mover to produce linear or rotational motion. It has the advantages of large output force and fast speed. Since the piezoelectric ultrasonic actuator itself works under resonance conditions and uses the friction between the stator and the mover as the driving force, its wear is severe and the problem of heat generation is difficult to solve. Direct-drive piezoelectric actuators usually use piezoelectric stacks or combine flexible displacement amplification mechanisms to directly act on the mover. They have large output force and high positioning accuracy. However, due to the limitation of the elongation of the piezoelectric stack, the stroke of direct-drive piezoelectric actuators is usually only a dozen microns, which limits their practical application in micro-nano manufacturing and precision driving. Bionic piezoelectric actuators, such as the inchworm type, are based on the bionic design of the inchworm's motion. They usually use three or more piezoelectric elements in a collaborative design and have a large driving force, but the structure of the positioning platform is correspondingly complicated and the control is more complicated. Compared with other types of piezoelectric actuators, parasitic inertia actuators have the most advantages in realizing compact micro-motion devices due to their simple structure, fast speed, low cost, theoretically unlimited displacement and the possibility of mass production. However, the piezoelectric actuators currently designed based on the parasitic inertia principle usually increase the speed by increasing the driving frequency, which will cause the actuator itself to heat up and wear, limiting its further development and application in related fields. Summary of the invention

[0004] The purpose of the present invention is to provide a parasitic inertia piezoelectric driver that can achieve low frequency and high speed, so as to solve the technical problem that the existing parasitic inertia piezoelectric driver cannot achieve high speed motion when driven by a low frequency signal. The present invention has a simple and compact structure and can achieve high speed output under low frequency signal drive.

[0005] To achieve the above-mentioned purpose, the present invention provides a parasitic inertia type piezoelectric driver for achieving low frequency and high speed, which mainly includes a positioning hole 1, a single degree of freedom displacement platform 2, a preload block I3, a piezoelectric stack I4, a movable guide rail 7, a fixed guide rail 8, a fixing screw 12, a piezoelectric stack II14, a preload block II15, a secondary lever flexible hinge mechanism 16, a metal connecting plate 17, a metal base 18, and a preload knob 19. The secondary lever flexible hinge mechanism 16 is composed of a first-level lever mechanism I5, a first-level lever mechanism II13, a second-level lever mechanism I6, a second-level lever mechanism II11, a driving foot 9, a Z-beam 10, a right-angle flexible hinge and a fixed base. The first-level lever mechanism I5, the first-level lever mechanism II13, the second-level lever mechanism I6 and the second-level lever mechanism II11 are arranged in parallel, and the angle with the moving direction of the moving guide rail is 120°. The first-level lever mechanism I5 and the first-level lever mechanism II13 have the same structure, and the second-level lever mechanism I6 and the second-level lever mechanism II11 have the same structure. The first-level lever mechanism I5 is on the right side of the second-level lever mechanism I6, and the first-level lever mechanism II13 is on the right side of the second-level lever mechanism II11. The first-level lever mechanism I5 and the first-level lever mechanism II13 are respectively connected to the second-level lever mechanism I6 and the second-level lever mechanism II11 through right-angle flexible hinges. The second-level lever mechanism is composed of a second-level lever mechanism I6 and a second-level lever mechanism II11 connected by a Z-shaped beam 10 to form a whole. The Z-shaped beam 10 is provided with a driving foot 9, which can drive the movable guide rail 7 to perform linear motion. Among them, the second-level lever mechanism, the right-angle flexible hinge, and the Z-shaped beam 10 all have good deformation effects. Under the drive of the piezoelectric stack, they are deformed and accumulated layer by layer to drive the movable guide rail to move; the piezoelectric stack I4 and the piezoelectric stack II14 are located inside the second-level lever flexible hinge mechanism 16, and are in contact with the first-level lever mechanism I5 and the first-level lever mechanism II13 respectively. The main output directions of the piezoelectric stacks I4 and II14 are consistent with the movement of the movable guide rail. The angle in the moving direction is 30°; the movable guide rail 7 adopts a high-precision linear guide rail with a slider, and the fixed guide rail 8 is fixed to the metal base 18 by screws to achieve high-precision linear motion. The secondary lever flexible hinge mechanism 16 is installed on the metal connecting plate 17 by screws, and the metal connecting plate 17 is installed on the metal base 18 by screws. The piezoelectric stack I4 and the piezoelectric stack II14 can be pre-tightened by the pre-tightening block I3 and the pre-tightening block II15 respectively. The positioning hole 1 can roughly adjust the relative position between the secondary lever flexible hinge mechanism 16 and the movable guide rail 7, and the pre-tightening knob 19 can finely adjust the initial pre-tightening force between the secondary lever flexible hinge mechanism 16 and the movable guide rail 7.

[0006] The advantages of the present invention are as follows: the first-level lever mechanism I5 and the first-level lever mechanism II13 are respectively connected with the second-level lever mechanism I6 and the second-level lever mechanism II11 through a right-angle flexible hinge to form a secondary lever mechanism, and the second-level lever mechanism I6 and the second-level lever mechanism II11 are connected by a Z-shaped beam 10 to form a whole, and the Z-shaped beam 10 is provided with a driving foot 9, which can drive the movable guide rail 7 to perform linear motion, wherein the secondary lever mechanism, the right-angle flexible hinge, and the Z-shaped beam all have good deformation effects, and when the piezoelectric stack I4 and the piezoelectric stack II14 are driven simultaneously, large deformations are generated and accumulated layer by layer, which has a good displacement amplification effect, and finally drives The movable guide rail 7 is used to produce a larger single-step displacement, thereby greatly increasing the driving speed; the secondary lever flexible hinge mechanism has high rigidity and can withstand a larger load. The main output direction of the piezoelectric stack I4 and the piezoelectric stack II14 is at an angle of 30° to the movement direction of the movable guide rail, and is pre-tightened and positioned with pre-tightening blocks I3 and II15. This arrangement makes full use of the larger rigidity of the main output direction of the piezoelectric stack, which can cause the driving foot to produce parasitic motion, thereby improving the load performance and motion stability of the entire device; it can be applied to important scientific and engineering fields such as precision and ultra-precision machining, micro-manipulation robots, micro-electromechanical systems, large-scale integrated circuit manufacturing, and biotechnology. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a front view of the present invention; Figure 3 It is a left side schematic diagram of the present invention; Figure 4 It is a two-stage lever flexible hinge mechanism of the present invention. DETAILED DESCRIPTION

[0008] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0009] A parasitic inertia piezoelectric driver for achieving low frequency and high speed mainly comprises a positioning hole 1, a single degree of freedom displacement platform 2, a preload block I3, a piezoelectric stack I4, a moving guide rail 7, a fixed guide rail 8, a fixing screw 12, a piezoelectric stack II14, a preload block II15, a secondary lever flexible hinge mechanism 16, a metal connecting plate 17, a metal base 18, and a preload knob 19. The secondary lever flexible hinge mechanism 16 has a good displacement amplification effect. The secondary lever flexible hinge mechanism 16 is composed of a first-level lever mechanism I5, a first-level lever mechanism II13, a second-level lever mechanism I6, a second-level lever mechanism II11, and a driving mechanism. The first-level lever mechanism I5, the first-level lever mechanism II13, the second-level lever mechanism I6 and the second-level lever mechanism II11 are arranged in parallel, and the angle with the moving direction of the moving guide rail is 120°. The first-level lever mechanism I5 and the first-level lever mechanism II13 have the same structure, and the second-level lever mechanism I6 and the second-level lever mechanism II11 have the same structure. The first-level lever mechanism I5 is on the right side of the second-level lever mechanism I6, and the first-level lever mechanism II13 is on the right side of the second-level lever mechanism II11. The first-level lever mechanism I5 and the first-level lever mechanism II13 are arranged in parallel, and the angle with the moving direction of the moving guide rail is 120°. The rod mechanism II13 is connected with the second-level lever mechanism I6 and the second-level lever mechanism II11 through a right-angle flexible hinge to form a secondary lever mechanism, and the second-level lever mechanism I6 and the second-level lever mechanism II11 are connected by a Z-shaped beam 10 to form a whole. The Z-shaped beam 10 is provided with a driving foot 9, which can drive the movable guide rail 7 to perform linear motion. Among them, the secondary lever mechanism, the right-angle flexible hinge, and the Z-shaped beam all have good deformation effects. Under the drive of the piezoelectric stack, large deformations are generated and accumulated layer by layer, and finally the movable guide rail is driven to produce a large single-step displacement, thereby greatly increasing the driving speed; the movable guide rail 7 adopts A high-precision linear guide with a slider is used. The fixed guide rail 8 is fixed to the metal base 18 by screws to achieve high-precision linear motion. The secondary lever flexible hinge mechanism 16 is installed on the metal connecting plate 17 by screws. The metal connecting plate 17 is installed on the metal base 18 by screws. The piezoelectric stack I4 and the piezoelectric stack II14 can be pre-tightened by the pre-tightening block I3 and the pre-tightening block II15 respectively. The positioning hole 1 can roughly adjust the relative position between the secondary lever flexible hinge mechanism 16 and the movable guide rail 7. The pre-tightening knob 19 can finely adjust the initial pre-tightening force between the secondary lever flexible hinge mechanism 16 and the movable guide rail 7.

[0010] The parasitic inertia type piezoelectric driver for achieving low frequency and high speed uses the parasitic inertia principle to achieve piezoelectric linear precision drive. The piezoelectric stack I4 and the piezoelectric stack II14 are located inside the secondary lever flexible hinge mechanism 16, and are in contact with the first-level lever mechanism I5 and the first-level lever mechanism II13 respectively. The main output direction of the piezoelectric stack I4 and the piezoelectric stack II14 forms an angle of 30° with the movement direction of the moving guide rail, making full use of the larger stiffness of the main output direction of the piezoelectric stack I4 and the piezoelectric stack II14; the secondary lever flexible hinge mechanism 16 generates a large deformation under the simultaneous drive of the two piezoelectric stacks to drive the moving guide rail 7 and achieve parasitic inertial motion. This motion mode of increasing the unit step length can greatly increase the speed of the moving guide rail 7 within the motion cycle, improve the output performance of the driver, and achieve linear motion of the moving guide rail 7 along a certain direction.

[0011] The length of the two piezoelectric stacks is changed by adjusting the voltage and frequency of the two piezoelectric stacks at the same time. Since the secondary lever flexible hinge mechanism 16 amplifies the length change of the piezoelectric stack, the drive can drive the movable guide rail to produce a unit step length far exceeding the elongation of the piezoelectric stack.

[0012] The specific working process of the present invention is as follows: The realization of the linear motion of the movable guide rail 7, the initial state: by selecting the positioning hole 1, the secondary lever flexible hinge mechanism 16 is roughly positioned to a suitable position away from the movable guide rail 7, and the preload knob 19 is adjusted to finely adjust the contact distance between the secondary lever flexible hinge mechanism 16 and the movable guide rail 7, that is, the initial preload force during the parasitic motion process; the piezoelectric stack I4 and the piezoelectric stack II14 are simultaneously controlled by an electrical signal in the form of a sawtooth wave or a triangular wave, and the piezoelectric stack I4 and the piezoelectric stack II14 are not charged, and the system In a free state, that is, both piezoelectric stacks are not extended, and the secondary lever flexible hinge mechanism 16 is not deformed; when the piezoelectric stack I4 and the piezoelectric stack II14 are energized at the same time, the piezoelectric stacks I4 and II14 are extended due to the inverse piezoelectric effect, pushing the secondary lever flexible hinge mechanism 16 to deform. The specific deformation process is that after the piezoelectric stacks I4 and II14 are extended, the first-stage lever mechanism I5 and the first-stage lever mechanism II13 inside the secondary lever flexible hinge mechanism 16 are deformed. The force and displacement of the two secondary levers are integrated by the Z-shaped beam 10, and the driving foot 9 thereon drives the movable guide rail 7 to perform linear motion in a certain direction, wherein the lever mechanism, the right-angle flexible hinge, and the Z-shaped beam all have good deformation effects, and produce large deformations and accumulate layer by layer under the drive of the piezoelectric stack I4 and the piezoelectric stack II14, and finally drive the movable guide rail 7 to produce a large single-step displacement, thereby greatly increasing the driving speed; the piezoelectric stack I4 and the piezoelectric stack II14 lose power and shorten, the deformation of the secondary lever flexible hinge mechanism 16 disappears, and the driving foot 9 moves in the opposite direction, but due to inertia, the displacement of the retreating motion is much smaller than the displacement during the forward motion, therefore, a large step length is accumulated within a unit period, and thus, the parasitic inertia type piezoelectric driver for achieving low frequency and high speed completes a motion cycle. By repeating the above steps, the driver can achieve low-frequency and high-speed linear motion in the desired direction.

Claims

1. A parasitic inertia type piezoelectric driver for achieving low frequency and high speed, mainly comprising a positioning hole (1), a single degree of freedom displacement platform (2), a preload block I (3), a piezoelectric stack I (4), a movable guide rail (7), a fixed guide rail (8), a fixing screw (12), a piezoelectric stack II (14), a preload block II (15), a secondary lever flexible hinge mechanism (16), a metal connecting plate (17), a metal base (18), and a preload knob (19), characterized in that: The secondary lever flexible hinge mechanism (16) is composed of a first-level lever mechanism I (5), a first-level lever mechanism II (13), a second-level lever mechanism I (6), a second-level lever mechanism II (11), a driving foot (9), a Z-shaped beam (10), a right-angle flexible hinge and a fixed base, wherein the first-level lever mechanism I (5), the first-level lever mechanism II (13), the second-level lever mechanism I (6) and the second-level lever mechanism II (11) are arranged in parallel and form an angle of 120° with the moving direction of the moving guide rail, the first-level lever mechanism I (5) and the first-level lever mechanism II (13) have the same structure, the second-level lever mechanism I (6) and the second-level lever mechanism II (11) have the same structure, the first-level lever mechanism I (5) is on the right side of the second-level lever mechanism I (6), and the first-level lever mechanism I (5) is on the right side of the second-level lever mechanism I (6). The second-stage lever mechanism II (13) is on the right side of the second-stage lever mechanism II (11); the first-stage lever mechanism I (5) and the first-stage lever mechanism II (13) are respectively connected with the second-stage lever mechanism I (6) and the second-stage lever mechanism II (11) through a right-angle flexible hinge to form a secondary lever mechanism, and the second-stage lever mechanism I (6) and the second-stage lever mechanism II (11) are connected by a Z-shaped beam (10) to form a whole, and the Z-shaped beam (10) is provided with a driving foot (9); the piezoelectric stack I (4) and the piezoelectric stack II (14) are located inside the secondary lever flexible hinge mechanism (16), and are in contact with the first-stage lever mechanism I (5) and the first-stage lever mechanism II (13) respectively, and the main output direction of the piezoelectric stack I (4) and the piezoelectric stack II (14) form an angle of 30° with the movement direction of the movable guide rail.

2. The parasitic inertia type piezoelectric actuator for achieving low frequency and high speed according to claim 1, characterized in that: The secondary lever mechanism, the right-angle flexible hinge, and the Z-shaped beam (10) are deformed and accumulated layer by layer under the drive of the piezoelectric stack, thereby driving the movable guide rail to move.

3. The parasitic inertia type piezoelectric actuator for achieving low frequency and high speed according to claim 1, characterized in that: The movable guide rail (7) adopts a high-precision linear guide rail with a slider, the fixed guide rail (8) is fixed to the metal base (18) by screws to achieve high-precision linear motion, the secondary lever flexible hinge mechanism (16) is installed on the metal connecting plate (17) by screws, and the metal connecting plate (17) is installed on the metal base (18) by screws, the piezoelectric stack I (4) and the piezoelectric stack II (14) can be pre-tightened by the pre-tightening block I (3) and the pre-tightening block II (15) respectively, the positioning hole (1) can roughly adjust the relative position between the secondary lever flexible hinge mechanism (16) and the movable guide rail (7), and the pre-tightening knob (19) can adjust the initial pre-tightening force between the secondary lever flexible hinge mechanism (16) and the movable guide rail (7).

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