A smart 3D ultrasonic actuator for unmanned vehicle guidance industrial applications

A smart piezoelectric ultrasonic actuator with multidegree of freedom for unmanned vehicle guidance industrial applications is presented in this paper. The proposed actuator is aiming to increase the visual spotlight angle of digital visual data capture transducer. Furthermore research are still undertaken to integrate the actuator with an infrared sensor, visual data capture digital transducers and obtain the trajectory of motion control algorithm. The actuator consists of three main parts, the stator, rotor and housing unit. The stator is a piezoelectric ring made from S42 piezoelectric material, bonded to three electrodes made from a material that has a close Characteristics to the S42. The rotor is a ball made from steel material. The actuator working principles is based on creating micro elliptical motions of surface points, generated by superposition of longitudinal and bending vibration modes, of oscillating structures. Transferring this motion from flexible ring transducer through the three electrodes, to the attached rotor, create 3D motions. The actuator Design, structures, working principles and finite element analysis are discussed in this paper. A prototype of the actuator was fabricated and its characteristics measured. Experimental tests showed the ability of the developed prototype to provide multidegree of freedom with typical speed of movement equal to 35 rpm, a resolution of less than 5μm and maximum load of 3.5 Newton. These characteristics illustrated the potential of the developed smart actuator, to gear the spotlight angle of digital visual data capture transducers and possible improvement that such microactuator technology could bring to the unmanned vehicle guidance and machine vision industrial applications

Preparations for Variable-Gravity Regolith Penetration with an Ultrasonically-Active Probe

The set of experiments proposed in this paper intend to investigate the properties of ultrasonic penetration through granular materials in hypergravity. As part of ESA's 6 th 'Spin Your Thesis' campaign, the University of Glasgow will be allowed to use the Large Diameter Centrifuge at the ESTEC facilities in Noordwijk, Netherlands, to achieve these hypergravity conditions. This paper describes the progress of the design and manufacture of the experimental apparatus, analysis of structural integrity to insure the rig can be subjected to the rigors of hypergravity, and discussion of the anticipated results and implications

A smart ultrasonic actuator with multidegree of freedom for autonomous vehicle guidance industrial applications

A piezoelectric ultrasonic actuator with multidegree of freedom for autonomous vehicle guidance industrial applications is presented in this paper. The actuator is aiming to increase the visual spotlight angle of digital visual data capture transducer. It consists of three main parts, the stator, rotor and housing unit. The stator is a piezoelectric ring made from S42 piezoelectric ceramics material, bonded to three electrodes made from a material that has a close Characteristics to the S42. The rotor is a ball made from stainless steel materials. The actuator working principles is based on creating micro elliptical motions of surface points, generated by superposition of longitudinal and bending vibration modes, of oscillating structures. Transferring this motion from flexible ring transducer through the three electrodes, to the attached rotor, create 3D motions. The actuator Design, structures, working principles and finite element analysis are discussed in this paper. A prototype of the actuator was fabricated and its characteristics measured. Experimental tests showed the ability of the developed prototype to provide multidegree of freedom with typical speed of movement equal to 35 rpm, a resolution of less than 5μm and maximum load of 3.5 Newton. These characteristics illustrated the potential of the developed smart actuator, to gear the spotlight angle of digital visual data capture transducers and possible improvement that such micro-actuator technology could bring to the autonomous vehicle guidance and machine vision industrial applications. Furthermore research are still undertaken to develop a universal control prototype, integrate the actuator with an infrared sensor, visual data capture digital transducers and obtain the trajectory of motion control algorithm

Desktop microforming and welding system powered by a flextensional Terfenol-D transducer

Magnetostrictive Terfenol-D was examined as a prime-mover for bulk motion in a microforming system. Careful design and analysis led to the creation of a Terfenol-D transducer capable of 3.8 kN of blocked force and 212 µm of displacement. A linear model of the Terfenol-D transducer to simulate its output as a function of displacement under saturation magnetic field was created that matched both force and displacement within 10%. Thermal drift occurred at a rate of 2 µm/ºC. A flextensional lever system was designed to amplify the displacement of the Terfenol-D transducer to levels sufficient for microforming. Sub-micron displacement resolution was observed, with no perceivable effects from friction or backlash. The full system provided 365 N of blocked force and 1.6 mm of displacement. A linear model of the full system was also created that used the linear model of the transducer\u27s output which matched experimental results for displacement with a 2% error and force with an 11% error, which was found to be useful for selection of design parameters. In ultrasonic-assisted punching, a circular punch of 3.2 mm diameter that vibrates transversely at 9.6 kHz was used to punch samples of 1100-O at several punching speeds and vibration intensities. Higher speed punching tests showed up to a 30% reduction in punching force accompanied by an apparent elimination of adiabatic strain rate effects. Lower speed punching showed a smaller degree of softening, but an increased burnished-to-fractured area ratio. A study on the effects of vibration waveform on a polymer vibration welding process on 0.25 and 0.5 mm ABS sheet was conducted using sine, square, and triangle waves at differing penetration depths. A preliminary study was first used to determine control levels of basic welding parameters that compared the effects of clamping load and penetration depth on the two sheet thicknesses. It was found that square waves provided slightly higher penetration rates than sine waves, and triangle waves significantly lower penetration rates than sine waves. Penetration rates and achievable penetration depths varied with sheet thickness. A minimum penetration rate threshold was found below which it was not possible to achieve adequate penetration; beyond this lower penetration rates generally resulted in higher strength

Novel Traveling Wave Sandwich Piezoelectric Transducer with Single Phase Drive: Theoretical Modeling, Experimental Validation, and Application Investigation

Most of traditional traveling wave piezoelectric transducers are driven by two phase different excitation signals, leading to a complex control system and seriously limiting their applications in industry. To overcome these issues, a novel traveling wave sandwich piezoelectric transducer with a single-phase drive is proposed in this study. Traveling waves are produced in two driving rings of the transducer while the longitudinal vibration is excited in its sandwich composite beam, due to the coupling property of the combined structure. This results in the production of elliptical motions in the two driving rings to achieve the drive function. An analytical model is firstly developed using the transfer matrix method to analyze the dynamic behavior of the proposed transducer. Its vibration characteristics are measured and compared with computational results to validate the effectiveness of the proposed analytical model. Besides, the driving concept of the transducer is investigated by computing the motion trajectory of surface points of the driving ring and the quality of traveling wave of the driving ring. Additionally, application example investigations on the driving effect of the proposed transducer are carried out by constructing and assembling a tracked mobile system. Experimental results indicated that 1) the assembled tracked mobile system moved in the driving frequency of 19410 Hz corresponding to its maximum mean velocity through frequency sensitivity experiments; 2) motion characteristic and traction performance measurements of the system prototype presented its maximum mean velocity with 59 mm/s and its maximum stalling traction force with 1.65 N, at the excitation voltage of 500 VRMS. These experimental results demonstrate the feasibility of the proposed traveling wave sandwich piezoelectric transducer

A short cylinder ultrasonic motor with novel excitation mode

This paper presents a short cylinder ultrasonic motor, which is featured by its new structure and novel excitation mode. The stator is composed of two piezoelectric disks and two short cylindrical blocks in which the disks are sandwiched by the blocks to form a special bolted Langevin type transducer. The corresponding vibrations are utilized to produce the driving force. A novel excitation mode is realized which can solve the problem of instability occurred in the conventional excitation mode. By using finite element analysis, the vibration pattern and driving mechanism are simulated. Finally, the proposed motor and its driving circuitry are prototyped to experimentally verify its validity and performance.published_or_final_versio

Modelización del estator de un motor piezoeléctrico de onda viajera: una revision integrada y nueva perspectiva

[EN] Articles from different areas which are closely related to the modelling of the stator of travelling wave ultrasonic motors (TWUMs) are reviewed in this work. Thus, important issues relevant to this problem are identified from the areas of vibration of annular plates, laminated plate theories, and modelling of piezoelectric transducers. From this integrated point of view, it becomes clear that there are some very important issues yet to be addressed in the modelling of TWUMs. Firstly, the influence of material properties and stator dimensions on output efficiency, electromechanical coupling coefficients (EMCC) and maximum output energy is to be investigated in more detail. Secondly, the modelling of the electric potential field (by explicitly including the charge equation) for TWUMs seems to be a must for better prediction of displacements and electric fields close to the resonance, as suggested by some recent works [1]. Moreover, the improvement of current models by using shear deformation (or higher order) laminated plate theories (LPTs) in conjunction with approximated methods of solution are discussed. In addition to analytical models, those works using Finite Element and Finite difference Methods (FEM and FDM) for the modelling and simulation of the TWUM stator dynamics are reviewed.[ES] En este trabajo se realiza una revisión de los trabajos de investigación realizados en diversas áreas sobre el modelado del estátor de los motores ultrasónicos de onda viajera (TWUMs). Entre los problemas relevantes que se han estudiado podemos citar la vibración de placas anulares, las teorías de placas laminadas y el modelado de transductores piezoeléctricos. A raíz de este punto de vista integral se hace manifiesto que todavía quedan asuntos importantes que estudiar en el modelado de los TWUMs. En primer lugar, la influencia de las propiedades del material y las dimensiones del estátor en la eficiencia del motor, los coeficientes de acoplamiento electromecánico (EMCC) y la máxima energía entregada deberían ser estudiados más detenidamente. En segundo lugar, el modelado de la distribución del campo eléctrico en los TWUMs (incluyendo la ecuación de carga explícitamente) parece imprescindible para lograr una predicción mejor del desplazamiento y del campo eléctrico cerca de la resonancia, como se ha apuntado en referencias actuales [1]. Además, se discute las mejoras que incorporaría a los modelos existentes en la actualidad la inclusión de las teorías de placas laminadas (LPTs) con deformaciones de corte (o de orden superior), resueltas mediante métodos aproximados. Como complemento a los modelos analíticos, se realiza asimismo una revisión de las técnicas de elementos finitos (FEM) y diferencias finitas (FDM) empleadas en la simulación de la dinámica del estátor de los motores TWUM.The authors are thankful for the support from the National Science and Research Office (Senacyt), the Institute for Human Resource Development and Proficiency (IFARHU), both of Panama, and the European Union for its support through grant DE-4205.Peer reviewe

A parametric study for the design of an optimized ultrasonic-percussive planetary drill tool

Traditional rotary drilling for planetary rock sampling, in situ analysis, and sample return are challenging because the axial force and holding torque requirements are not necessarily compatible with lightweight spacecraft architectures in low-gravity environments. This paper seeks to optimize an ultrasonic percussive drill tool to achieve rock penetration with lower reacted force requirements, with a strategic view toward building an ultrasonic planetary core drill (UPCD) device. The UPCD is a descendant of the ultrasonic/sonic driller/corer technique. In these concepts, a transducer and horn (typically resonant at around 20 kHz) are used to excite a toroidal free mass that oscillates chaotically between the horn tip and drill base at lower frequencies (generally between 10 Hz and 1 kHz). This creates a series of stress pulses that is transferred through the drill bit to the rock surface, and while the stress at the drill-bit tip/rock interface exceeds the compressive strength of the rock, it causes fractures that result in fragmentation of the rock. This facilitates augering and downward progress. In order to ensure that the drill-bit tip delivers the greatest effective impulse (the time integral of the drill-bit tip/rock pressure curve exceeding the strength of the rock), parameters such as the spring rates and the mass of the free mass, the drill bit and transducer have been varied and compared in both computer simulation and practical experiment. The most interesting findings and those of particular relevance to deep drilling indicate that increasing the mass of the drill bit has a limited (or even positive) influence on the rate of effective impulse delivered