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

Analysis of planned motion trajectories for scalable micro-robots

Prototypes of micro-robots and geometric path planning algorithms are presented in this paper. Geometric motion trajectories are generated by switching contacts, control points and tangents methods. Analysis of high-speed formation of trajectories using switching contacts method revealed that the geometric path depends on orientation angle of a micro-robot. Investigation of formation of high-precision trajectories demonstrated that there is minimal deviation from the given motion trajectory at which micro-robot stops. This paper presents methodologies for evaluation of optimal orientation angle of a micro-robot and minimum deflection from the given trajectory. The methodologies are verified by experiments

Piezoelectric actuator with traveling wave waveguide

A novel design of traveling wave piezoelectric actuator with a special waveguide is investigated in the paper. Actuator consists of cylinder type waveguide and piezo ceramic ring. Waveguide has conical hole inside. Such configuration of the waveguide allows increasing amplitudes of the traveling wave vibrations. Electrodes of piezoceramic ring are divided into four equal sections. Four electric signals with shifted phases by π/2 are used for the excitation. Numerical simulation was carried out to optimize the shape and dimensions of the waveguide and to maximize oscillation amplitudes at the contact surface of the waveguide. Mathematical model of the contact interface between stator and rotor was developed. A prototype piezoelectric actuator was made and experimental investigation was performed. Results of numerical and experimental investigation are discussed

Novel attitude control devices for CubeSat satellites

In recent years a very modern trend of space exploration activities – constructing, launching and operating nano-satellites, became very popular. One of the main problems in implementation and control of nano-satellite is ensuring accurate yet simple and small-sized attitude control equipment. Most of the equipment implemented for that task in the past was large, bulky and could be hardly used on extremely small CubeSat standard nano-satellites. The equipment under development for attitude control of the satellites is described in this paper. The equipment relies on implementation of piezoelectric transducers for rotation of spherical body – reaction sphere, thus ensuring precise three-axis attitude control of the satellite by means of single device. Description of the device under development with some calculations and examples of implementation of such instrumentation is further described in the paper

Piezoelectric mirror with an active kinematic pair

Accuracy of laser optical beam steering strongly depends on dynamic characteristics of the positioning mechanism of the mirror. Novel design of the beam steering mirror with an integrated piezoelectric active kinematic pair is introduced in the paper. Rotation mechanism of the mirror has a simple design and allows achieving nano-scale resolution. Rotation of the mirror is achieved by exciting harmonic vibrations in the special clamping mechanism. Plate type piezoelectric transducer is used to generate vibrations. Two different electrode patterns and excitation schemes of the actuator are analyzed. Numerical modelling was performed to confirm operating principle of the rotation mechanism. Experimental prototype of the piezoelectric mirror was made and corresponding measurements were performed. Results of numerical and experimental studies are discussed

Analysis of planned motion trajectories for scalable micro-robots

Prototypes of micro-robots and geometric path planning algorithms are presented in this paper. Geometric motion trajectories are generated by switching contacts, control points and tangents methods. Analysis of high-speed formation of trajectories using switching contacts method revealed that the geometric path depends on orientation angle of a micro-robot. Investigation of formation of high-precision trajectories demonstrated that there is minimal deviation from the given motion trajectory at which micro-robot stops. This paper presents methodologies for evaluation of optimal orientation angle of a micro-robot and minimum deflection from the given trajectory. The methodologies are verified by experiments

Design and the main parameters of tube-shaped ultrasound wave guide wire

Cardiovascular diseases are the leading cause of death among people up to 65 years old. One of the most common cardiovascular diseases is arterothrombosis. For recanalization of arteries usage of advanced invasive mechanical devices is required. The tube-shaped ultrasound waveguide wire was designed, investigated and validated by computational finite element method and experimental techniques

Cost-value pricing model in Green marketing mix

Straipsnyje autoriai apžvelgia marketingo koncepcijų evoliuciją, žaliojo marketingo sampratą, akcentuoja kainodaros svarbą marketingo komplekse. Nagrinėjama vartotojų suvokiamos produkto vertės analizės svarba jo priimamiems pirkimo sprendimams. Vertinamos kaštų - vertės kainos nustatymo modelio panaudojimo perspektyvos žaliojo marketingo komplekseVytauto Didžiojo universiteta

Trapezoidal Cantilevers with Irregular Cross-Sections for Energy Harvesting Systems

The results of numerical and experimental investigation of trapezoidal cantilevers with irregular cross-sections are presented in this paper. Modifications of the cross-section were made in order to increase strain and improve its distribution in the piezo ceramic layer of a cantilever. The proposed modifications allowed improving the energy conversion coefficient and increasing the power density. The numerical investigation revealed that modifications have a positive influence on strain and its distribution characteristics. Moreover, the electrical characteristics of piezoelectric cantilevers were investigated by employing a numerical model. The analysis of the results revealed that modifications of the cross-section have positively affected the electrical outputs of the cantilevers. The results of the numerical investigation were validated by experimental investigation. Experimental investigation showed that output voltage density was increased by 9.9%, output current density by 6.9% and power density by more than three-times compared with a conventional cantilever

Elektroninis marketingas : [mokomoji knyga]

Bibliogr.: p. 180-183Šioje mokomojoje studijų knygoje nagrinėjama marketingo raida, elektroninio verslo pagrindai ir elektroninio marketingo orientacija. Apibrėžiama internetinio marketingo samprata ir esmė. Elektroninis marketingas analizuojamas kaip procesas, kurio metu sukuriami ir palaikomi santykiai su klientu naudojant internetines technologijas, norint palengvinti informacijos, produktų ir paslaugų, kurios tenkina abiejų pusių reikalavimus, kaitą. Studijų knyga parengta remiantis įvairių užsienio ir Lietuvos autorių publikacijomis. Knyga skirta VDU magistrantams, studijuojantiems Elektroninį marketingą, Elektroninę komerciją, studentams, specialistams, dirbantiems elektroninio marketingo srityje (ar ketinantiems jais tapti)Ekonomikos ir vadybos fakultetasVytauto Didžiojo universiteta