PENINGKATAN SENSITIVITAS SENSOR KOIL DATAR MEMPERGUNAKAN SOFT MAGNETIC VITROVAC

This study reports the design of non-magnetic plate thickness sensors based on Eddy Current principld in the form of flat coils. The principle used in the Eddy Current sensor is a change of mutual coil inductance due to the presence of objects in the magnetic field. The coil is made up of single and double layer coil designed using Corel Draw Software based on printed circuit board (PCB) material with dimensions of 152.4 mm x 101.6 mm, which has a track distance of 0.125 m. Single and double layer coil inductance evaluations are carried out using the EVB  LDC 1000 L/V Converter module which converts plate thickness into inductance values. The addition of a 30 mm Vitrovac thin film mounted in the direction of the winding in the 2 mm diameter coil core has been carried out to increase the sensitivity value of the sensor which gives an increase in sensitivity value of S = 0.321 uH / mm or 33.2%. The coil is able to measure plate thickness up to 10mm well

Design and Characterization of Tri-axis Soft Inductive Tactile Sensors

Tactile sensors are essential for robotic systems to safely and effectively interact with the environment and humans. In particular, tri-axis tactile sensors are crucial for dexterous robotic manipulations by providing shear force, slip or contact angle information. The Soft Inductive Tactile Sensor (SITS) is a new type of tactile sensor that measures inductance variations caused by eddy-current effect. In this paper, we present a soft tri-axis tactile sensor using the configuration of four planar coils and a single conductive film with hyperelastic material in between them. The working principle is explained and design methods are outlined. A 3D finite element model was developed to characterize the tri-axis SITS and to optimize the target design through parameter study. Prototypes were fabricated, characterized and calibrated, and a force measurement resolution of 0.3 mN is achieved in each axis. Demonstrations show that the sensor can clearly measure light touch (a few mN normal force) and shear force pulses (10 to 30 mN) produced by a serrated leaf when it is moved across the sensor surface. The presented sensor is low cost, high performance, robust, durable, and easily customizable for a variety of robotic and healthcare applications

Characteristics of Eddy Current Attenuation and Thickness Measurement of Metallic Plate

Abstract(#br)In eddy current testing, the law of attenuation of eddy current (EC) is of great concern. In conductive half space under the excitation of uniform magnetic field, the EC density decreases exponentially in the depth direction. However, in conductor with finite thickness tested by coil, the distribution of EC in the depth direction is more complicated. This paper studies the characteristics of EC attenuation in metallic plate of finite thickness. Simulation results show that there is an EC reflection at the bottom of plate, which changes the law of EC attenuation. A new concept, namely the equivalent attenuation coefficient, is proposed to quantify the speed of EC attenuation. The characteristics of EC attenuation are utilized to explain the nonmonotonic relation between coil..

Robust and High-Performance Soft Inductive Tactile Sensors based on the Eddy-Current Effect

Tactile sensors are essential for robotic systems to interact safely and effectively with the external world, they also play a vital role in some smart healthcare systems. Despite advances in areas including materials/composites, electronics and fabrication techniques, it remains challenging to develop low cost, high performance, durable, robust, soft tactile sensors for real-world applications. This paper presents the first Soft Inductive Tactile Sensor (SITS) which exploits an inductance-transducer mechanism based on the eddy-current effect. SITSs measure the inductance variation caused by changes in AC magnetic field coupling between coils and conductive films. Design methodologies for SITSs are discussed by drawing on the underlying physics and computational models, which are used to develop a range of SITS prototypes. An exemplar prototype achieves a state-of-the-art resolution of 0.82 mN with a measurement range over 15 N. Further tests demonstrate that SITSs have low hysteresis, good repeatability, wide bandwidth, and an ability to operate in harsh environments. Moreover, they can be readily fabricated in a durable form and their design is inherently extensible as highlighted by a 4x4 SITS array prototype. These outcomes show the potential of SITS systems to further advance tactile sensing solutions for integration into demanding real-world applications

Electromagnetic Behavior of Cu and Ni Nanofilms in the X-band

Currently, the presence of spurious microwave radiation is increasing in the environment, which has caused concern due to possible health problems in living beings and electromagnetic interference in electronic systems. To control this problem, studies in the materials area are taking place, aiming to attenuate the spurious radiation and meet requirements of good performance in broadband, low cost and low weight. The present work aimed to study Cu and Ni nanometric films with thicknesses of 65 and 200 nm, deposited on polyethylene terephthalate substrate by magnetron sputtering. Scanning electron microscopy with a field emission gun (FEGSEM) showed that the films produced have different morphological textures, due to the parameters used in the sputtering process and also the free energy of metals. Impedance spectroscopy measurements showed that the films have low conductivity values, due to the metallic oxides formed on the film surfaces, confirmed by X-ray diffraction, and also to the presence of defects. Electromagnetic characterization (8.2 – 12.4 GHz) showed that the Cu and Ni thin films had low performance, except the Ni_200 nm film, which showed a total shielding efficiency of about 30% in broadband. This result is promising considering the nanometric thickness of the Ni film

Contribuciones en el área de sondas y algoritmos aplicadas a la detección de discontinuidades, metrología de distancia y clasificación de materiales con técnicas no destructivas basadas en corrientes inducidas

Se presenta esta tesis doctoral sobre sondas y algoritmos de procesado de datos de técnicas de ensayos no destructivas basadas en corrientes inducidas. El objetivo ha sido proponer (i) sondas para la detección de discontinuidades, y la metrología de espesor de recubrimiento no conductor, y (ii) redes neuronales para tratar los datos base mono y multifrecuencia para la clasificación de piezas con diferente temple. Del Ensayo 1, la Sonda 1 inductiva ha proporcionado mejores resultados que la Sonda 2 con sensor Hall en (i) respuesta frecuencial, (ii) detección de agujeros y (iii) predicción de espesor. Del Ensayo 2, la Sonda 3 inductiva y las redes neuronales han proporcionado mejores resultados con el procesado multifrecuencia en cuanto a (iv) tasa de acierto, (v) carga computacional; y (vi) tiempo de ejecución. Los resultados sugieren utilizar las sondas inductivas puras y redes con procesado multifrecuencia para la resolución de los problemas inversos presentados.Departamento de Teoría de la Señal, Comunicaciones e Ingeniería TelemáticaDoctorado en Tecnologías de la Información y las Telecomunicacione