Bionic creeping type piezoelectric actuator
Technical Field
The invention relates to the field of precise and ultra-precise machining, micro-nano operation robots and micro electro mechanical systems, in particular to a bionic crawling type piezoelectric driver.
Background
The precise driving technology with micro/nano positioning precision is a key technology in high-end scientific and technical fields such as ultra-precision machining and measurement, optical engineering, modern medical treatment, aerospace technology and the like. In order to realize the micro/nano-scale output precision, the application of the modern precision driving technology puts higher requirements on the precision of the driving device. The traditional driving device has low output precision and large integral size, and cannot meet the requirements of a precision system in the modern advanced technology on micro/nano-scale high precision and small size of the driving device. The piezoelectric ceramic driver has the advantages of small volume size, high displacement resolution, large output load, high energy conversion rate and the like, can realize micro/nano-scale output precision, and is increasingly applied to micro positioning and precise ultra-precision machining. In the conventional piezoelectric inertia driving device, a piezoelectric element and a rotor mass block are usually arranged in parallel in the motion direction of the piezoelectric element, the pretightening force is perpendicular to the main output direction of the piezoelectric element, and the output load of the whole device mainly depends on the friction force generated by the pretightening force. However, a piezoelectric element such as a piezoelectric stack generally adopts a d33 operating mode, and the rigidity of the piezoelectric element on a cross section perpendicular to the main output direction is small, so that the generated pretightening force is small, the output load of the whole device is greatly reduced, and the large rigidity of the piezoelectric element in the main output direction is not fully utilized; the output load provided by a single piezoelectric stack is small; the rollback phenomenon in motion further degrades output performance. Therefore, it is necessary to design a piezoelectric driver that fully utilizes the stiffness of the piezoelectric stack in the main output direction, eliminates the rollback phenomenon, improves the output load, and further improves the output load of the piezoelectric driving device by generating the pretightening force and the driving force through the parasitic inertia motion of the asymmetric thin-wall flexible hinge mechanism.
Disclosure of Invention
The invention aims to provide a bionic crawling type piezoelectric actuator, which solves the problems in the prior art. The invention has the characteristics of simple and compact structure, high output precision, high output rigidity and output load and high output frequency, and can realize the linear motion output function.
The bionic crawling type piezoelectric power generator adopts two groups of piezoelectric driving units, the main output direction of the piezoelectric stacks and the motion direction of the rotor are obliquely arranged, two asymmetric flexible hinge mechanisms connected by four thin-wall flexible hinges are adopted, and parasitic inertia motion is sequentially realized by the asymmetric thin-wall flexible hinge mechanisms according to time sequence under the alternate driving of the two piezoelectric stacks.
The above object of the present invention is achieved by the following technical solutions:
a bionic creeping type piezoelectric driver comprises a piezoelectric stack (3), an asymmetric thin-wall flexible hinge mechanism (4), a piezoelectric stack (7), an asymmetric thin-wall flexible hinge mechanism (6), a rotor (5), a pre-tightening wedge block (2), a pre-tightening wedge block (8), a pre-tightening knob (1), a pre-tightening knob (10) and a base (9), wherein the precise driving device realizes micro-nano bionic creeping type precise linear driving by utilizing a parasitic inertia principle. The rotor (5) adopts a high-precision linear guide rail with a slide block, and the guide rail is fixed on the base (9) through a screw; the asymmetric thin-wall flexible hinge mechanism (4) and the asymmetric thin-wall flexible hinge mechanism (6) are arranged on the base (9) through screws; the pre-tightening wedge block (2) is arranged between the piezoelectric stack (3) and the asymmetric thin-wall flexible hinge mechanism (4), the pre-tightening wedge block (8) is arranged between the piezoelectric stack (7) and the asymmetric thin-wall flexible hinge mechanism (6), and the piezoelectric stack (3) and the piezoelectric stack (7) can be pre-tightened through the pre-tightening wedge block (2) and the pre-tightening wedge block (8) respectively; the pre-tightening knob (1) and the pre-tightening knob (10) are fastened on the base (9) and are in contact with the lower ends of the asymmetric thin-wall hinge mechanism (4) and the asymmetric thin-wall hinge mechanism (6); the asymmetric thin-wall hinge mechanism (4) and the asymmetric thin-wall hinge mechanism (6) are formed in an asymmetric mode by connecting four thin-wall flexible hinges, and the arc-shaped structure at the upper end of the asymmetric thin-wall hinge mechanism is in contact with the rotor (5); the base (9) plays a role in supporting and installing and fixing other parts.
The piezoelectric stacks (3) and (7) are respectively arranged in the asymmetric thin-wall flexible hinge mechanism (4) and the asymmetric thin-wall flexible hinge mechanism (6), the piezoelectric stacks (3) are driven to drive the asymmetric thin-wall flexible hinge mechanism (4) to extend, the piezoelectric stacks (7) are driven to drive the asymmetric thin-wall flexible hinge mechanism (6) to extend, and the bionic crawling type motion among the asymmetric thin-wall flexible hinge mechanism (4), the asymmetric thin-wall flexible hinge mechanism (6) and the rotor (5) is realized by controlling the time sequence between the piezoelectric stacks (3) and the piezoelectric stacks (7), so that the rotor (5) is driven to linearly and precisely move.
The initial pretightening force among the asymmetric thin-wall flexible hinge mechanism (4), the asymmetric thin-wall flexible hinge mechanism (6) and the rotor (5) is respectively adjusted through the pretightening knob (1) and the pretightening knob (10);
the piezoelectric stacks (3) and (7) adopt piezoelectric ceramic stacks PZT with controllable shapes and surfaces, parasitic inertial motion is realized by controlling the voltage of the piezoelectric stacks (3) and (7), and bionic crawling type linear driving can be realized by orderly controlling the voltage of the piezoelectric stacks (3) and (7).
The main advantages of the invention are: the main output direction of the piezoelectric stack and the motion direction of the rotor are obliquely arranged by utilizing a parasitic inertial motion principle; two asymmetric flexible hinge mechanisms connected by four thin-wall flexible hinges are adopted; under the alternate driving of the two piezoelectric stacks, the asymmetric thin-wall flexible hinge mechanism sequentially performs parasitic inertia motion according to time sequence, and the bionic crawling motion can eliminate the backspacing phenomenon of the rotor in the motion period; the invention can greatly improve the output performance of the device, realizes the linear motion of the rotor along a certain direction, and has the advantages of high driving reliability, good stability, high working efficiency and the like; the method can be applied to the important scientific engineering fields of precision ultra-precision machining, micro-operation robots, micro-electro-mechanical systems, large-scale integrated circuit manufacturing, biotechnology and the like; the invention has the advantages of simple structure, compact arrangement, stable movement, high efficiency, low investment, high benefit and the like, and has wider application prospect.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic front view of the present invention;
FIG. 3 is a schematic left side view of the present invention;
FIG. 4 is a schematic view of an asymmetric thin wall flexible hinge mechanism of the present invention.
Detailed Description
The details of the present invention and its embodiments are further described below with reference to the accompanying drawings.
Referring to fig. 1 to 4, the bionic crawling type piezoelectric driver mainly comprises a rotor (5), a piezoelectric stack (3), a piezoelectric stack (7), a pre-tightening wedge block (2), a pre-tightening wedge block (8), a pre-tightening knob (1), a pre-tightening knob (10), an asymmetric thin-wall flexible hinge mechanism (4), an asymmetric thin-wall flexible hinge mechanism (6) and a base (9), and the precise driving device realizes piezoelectric linear precise driving through a parasitic inertia principle. The rotor (5) adopts a high-precision linear guide rail with a slide block, and the guide rail is fixed on the base through a screw; the asymmetric thin-wall flexible hinge mechanism (4) and the asymmetric thin-wall flexible hinge mechanism (6) are arranged on the base through screws; the piezoelectric stacks (3) and (7) are respectively arranged in the asymmetric thin-wall flexible hinge mechanism (4) and the asymmetric thin-wall flexible hinge mechanism (6), and the main output direction of the piezoelectric stacks and the motion direction of the rotor (5) are obliquely arranged; the pre-tightening wedge block (2) is arranged between the piezoelectric stack (3) and the asymmetric thin-wall flexible hinge mechanism (4), the pre-tightening wedge block (8) is arranged between the piezoelectric stack (7) and the asymmetric thin-wall flexible hinge mechanism (6), and the piezoelectric stack (3) and the piezoelectric stack (7) can be pre-tightened through the pre-tightening wedge block (2) and the pre-tightening wedge block (8) respectively; the pre-tightening knob (1) and the pre-tightening knob (10) are fastened on the base (9) and are in contact with the lower ends of the asymmetric thin-wall hinge mechanism (4) and the asymmetric thin-wall hinge mechanism (6); the asymmetric thin-wall hinge mechanism (4) and the asymmetric thin-wall hinge mechanism (6) are formed in an asymmetric mode by connecting four thin-wall flexible hinges, and the arc-shaped structure at the upper end of the asymmetric thin-wall hinge mechanism is in contact with the rotor (5); the base (9) plays a role in supporting and installing and fixing other parts, and the asymmetric thin-wall flexible hinge mechanism (4), the asymmetric thin-wall flexible hinge mechanism (6) and the rotor (5) are installed on the base (9) through screws.
The bionic creeping type piezoelectric actuator realizes piezoelectric linear precision driving by utilizing a parasitic inertia principle. The main output directions of the piezoelectric stacks (3) and (7) and the motion direction of the rotor (5) are obliquely arranged, so that the large rigidity of the piezoelectric stacks (3) and (7) in the main output directions is fully utilized; the asymmetric thin-wall flexible hinge mechanism (4) and the asymmetric thin-wall flexible hinge mechanism (6) have good rigidity output performance, can bear larger pretightening force, and move stably and efficiently, the piezoelectric stack (3) and the piezoelectric stack (7) are electrified to transmit the driving force of the linear motion of the rotor (5) and the pretightening force between the asymmetric thin-wall flexible hinge mechanism (4) and the asymmetric thin-wall flexible hinge mechanism (6) and the rotor (5) respectively through the asymmetric thin-wall flexible hinge mechanism (4) and the asymmetric thin-wall flexible hinge mechanism (6), so that the output load of the piezoelectric driving device is greatly improved, and the linear motion along a certain direction is realized.
The initial pretightening force between the asymmetric thin-wall flexible hinge mechanism (4), the asymmetric thin-wall flexible hinge mechanism (6) and the rotor (5) is adjusted through the pretightening knob (1) and the pretightening knob (10).
The piezoelectric stacks (3) and (7) adopt piezoelectric ceramic stacks PZT with controllable surface shapes, and parasitic inertial motion is realized by controlling the voltage of the piezoelectric stacks (3) and (7).
Referring to fig. 1 to 4, the specific working process of the present invention is as follows:
realizing linear motion of the rotor, and in an initial state: adjusting a pre-tightening knob (1) to adjust the contact distance between the asymmetric thin-wall flexible hinge mechanism (4) and the rotor (5), and adjusting a pre-tightening knob (10) to adjust the contact distance between the asymmetric thin-wall flexible hinge mechanism (6) and the rotor (5), namely the initial pre-tightening force in the parasitic motion process; the piezoelectric stack (3) and the piezoelectric stack (7) are controlled by adopting a piezoelectric signal in a sawtooth wave or triangular wave form, and the piezoelectric stack (3) and the piezoelectric stack (7) are sequentially electrified according to a time sequence by controlling voltage; the piezoelectric stacks (3) and (7) are not electrified, and the system is in a free state; when the piezoelectric stack (3) is electrified, the piezoelectric stack is extended through the inverse piezoelectric effect to push the asymmetric thin-wall flexible hinge mechanism (4) to deform, the rotor (5) is pressed by the asymmetric thin-wall flexible hinge mechanism (4), and the rotor (5) is driven to move by the asymmetric thin-wall flexible hinge mechanism (4) under the action of the static friction force between the rotor (5) and the rotor; when the piezoelectric stack (3) loses power and rapidly returns to an initial position, the asymmetric thin-wall flexible hinge mechanism (4) also returns to the initial state, the rotor (5) is still kept at the moved position under the action of inertia force, meanwhile, the piezoelectric stack (7) is electrified, the piezoelectric stack is extended through the inverse piezoelectric effect to push the asymmetric thin-wall flexible hinge mechanism (6) to deform, the asymmetric thin-wall flexible hinge mechanism (6) compresses the rotor (5), and the asymmetric thin-wall flexible hinge mechanism (6) drives the rotor (5) to move under the action of static friction force between the rotor (5) and the rotor (6); when the piezoelectric stack (7) loses power and rapidly retracts to the initial position, the asymmetric thin-wall flexible hinge mechanism (6) also restores to the initial state, and the mover (5) is still kept at the position after the second movement under the action of inertia force, so that one movement cycle of the driving device is completed. By repeating the steps, the driving device can realize linear motion in the required direction, and large output displacement is obtained.
The bionic creeping type piezoelectric actuator adopts two groups of piezoelectric stacks as driving sources and an asymmetric thin-wall type flexible hinge mechanism as a power transmission element, has the characteristics of small heat, stable driving, reliability and high efficiency, and can realize the functions of linear precise motion and the like.