Development of traveling wave actuators using waveguides of different geometrical forms

The paper covers the research and development of piezoelectric traveling wave actuators using different types of the waveguides. The introduced piezoelectric actuators can be characterized by specific areas of application, different resolution, and torque. All presented actuators are ultrasonic resonant devices and theywere developed to increase amplitudes of the travelingwave oscillations of the contact surface.Three different waveguides are introduced, that is, symmetrical, asymmetrical, and cone type waveguide. A piezoelectric ring with the sectioned electrodes is used to excite traveling wave oscillations for all actuators. Operating principle, electrode pattern, and excitation regimes of piezoelectric actuators are described. A numerical modelling of the actuators was performed to validate the operating principle and to calculate trajectories of the contact points motion. Prototype actuators were made and experimental study was performed.The results of numerical and experimental analysis are discussed

Excitation of 2D resonant oscillations in piezoelectric plate with additional masses

This article presents results of investigation of piezoelectric transducer which consists of rectangle homogeneous piezoceramic plate with two additional masses glued on the top surface of the transducer. Because of additional masses and a certain sectioning of piezoelectric electrodes, the vibration forms of the plate and resonant frequencies are changed, therefore, the plate generates 3D longitudinal and bending vibrations. Numerical and experimental investigation showed that the masses glued at the surface of piezoelectric plate obtain elliptical trajectories of motion when the first mode of longitudinal vibrations of the plate is excited. Such form of vibrations of the masses enables using them for various piezoelectric drive mechanisms as contact elements and to transform high-frequency vibrations into the directional or rotational movement of the rotor or slider. In order to examine the deformations and dynamic characteristics of the homogenous piezoelectric plate with two additional masses, the numerical modelling of such piezo transducer and the experimental study have been carried out

Cylindrical piezorobot’s trajectory planning and control

This paper analyses the movement of piezoelectric actuator. The goal of this work was to create an algorithm for trajectory planning of piezorobot, create a system for trajectory control, develop software and verify the functioning of the algorithm in practice. Movements of piezorobot are very small and very frequent therefore it is difficult to measure trajectories using standard equipment. Design of a novel measurement system and trajectory adjustment was created in this paper. An experimental system for control and trajectory movement tracking of piezorobot was developed. It consists of cylindrical piezorobot, control signal forming and image processing system for trajectory tracking. The cylindrical piezorobot moves in specific trajectories on the plane and is controlled with sinusoidal signals. They are generated by trajectory forming and control software using MATLAB and LabVIEW. The control signals are monitored using a system with oscilloscope. The trajectory of piezorobot was monitored and measured using video camera and video processing software developed by LabVIEW. The software contains image processing and object path tracking, and is implemented using LabVEW and MATLAB. Experimental results showed that trajectories forming algorithm and developed control software is suitable for controlling robots moving on plane

Single Cylinder-Type Piezoelectric Actuator with Two Active Kinematic Pairs

There is an ever-increasing demand for small-size, low-cost, and high-precision positioning systems. Therefore, investigation in this field is performed to search for various solutions that can meet technical requirements of precise multi-degree-of-freedom (DOF) positioning systems. This paper presents a new design of a piezoelectric cylindrical actuator with two active kinematic pairs. This means that a single actuator is used to create vibrations that are transformed into the rotation of the sphere located on the top of the cylinder and at the same time ensure movement of the piezoelectric cylinder on the plane. Numerical and experimental investigations of the piezoelectric cylinder have been performed. A mathematical model of contacting force control was developed to solve the problem of positioning of the rotor when it needs to be rotated or moved according to a specific motion trajectory. The numerical simulation included harmonic response analysis of the actuator to analyze the trajectories of the contact points motion. A prototype actuator has been manufactured and tested. Obtained results confirmed that such a device is suitable for both positioning and movement of the actuator in the plane.This article belongs to the Special Issue Piezoelectric Transducers: Materials, Devices and ApplicationsThis research was funded by the European Regional Development Fund according to the supported activity No. 01.2.2-LMT-K-718 under the project No. DOTSUT-234

Three degree of freedom piezoelectric actuator for precise positioning

A novel three degrees of freedom actuator is introduced and investigated in this paper. Actuator comprises a single cylinder type piezoelectric transducer with a disc shaped resonator glued on the top of the cylinder and a reflecting mirror. Ring shaped permanent magnet is used to clamp mirror on a steel hemisphere that is located in the center of the disc resonator. Actuator can realize up to three degrees of freedom i.e. to rotate the mirror about three axes independently. Harmonic vibrations of the resonator are excited by piezoelectric transducer and are employed to rotate the mirror. Bi-directional rotation of the mirror is obtained by switching excitation signals between different electrodes of the transducer. Both numerical simulation and physical prototype are used to verify the operating principle and results. Numerical investigation of the piezoelectric actuator was performed to investigate modal-frequency and harmonic response analysis of the piezoelectric actuator. Experimental study was used to measure electrical and mechanical output characteristics of the piezoelectric actuator. Results are analyzed and discussedKauno technologijos universitetasVilniaus Gedimino technikos universitetasVytauto Didžiojo universitetasŠvietimo akademij

Miniature high resolution laser beam deflectors with multi DOF piezoelectric kinematic pairs

Research and development of high resolution miniature piezoelectric 1DOF and 2DOF laser beam deflectors are presented in the paper. All deflectors feature a simple design and practically unlimited angular displacement. The first group of the presented deflectors includes devices with an active mirror. External surface of the mirror is covered by piezoelectric layer with sectioned electrodes. Two and four electrode sections are used for 1DOF and 2 DOF deflector respectively. The second group of the deflectors contains application of the “shaking beam” type actuators. Two different designs of actuators are presented. Both of the actuators have driving tip located in the center of the actuator. A harmonic electric signal is used to drive deflectors of the both groups. The experimental results confirmed the operating principle of the deflectors. A high resolution of the deflectors was achieved during experimental studyKauno technologijos universitetasVilniaus Gedimino technikos universitetasVytauto Didžiojo universitetasŠvietimo akademij