Mems Teknikleri Kullanarak Esnek Piezoelektrik Dokunsal Algılayıcı Dizini Üretimi

Abstract

Tactile sensor is used in many applications such as robotics, computer hardware, manufacturing of automobiles (brakes, door seals, gaskets), security systems and dentistry. The most known application of tactile sensors is touch screen that is used in mobile phones and computer screen. In recent years, tactile sensors are studied and developed in robotics and minimally invasive surgery. In robotics, the emphasis is on building humanlike robots. In traditional industrial robotics, robots perform simple work on production line like painting/coating, welding and assembly. On the other hand, human being need specific robots, which assist human life for many areas, like hazardous work, medical services. Tactile sensors define as a device that can measure a given property of an object or contact event through physical contact between the sensor and the object. Tactile sensor is mimicking a human finger, which is the most sensitive sensor for touching. The human finger can feel at a spatial resolution of about 40 m over a contact area of 1 cm2 and at stress level of 10-40 kPa. In this work, sensing of the pressure is focused and studied and this work aims at designing and producing micro polymer fiber arrays of integrated tactile sensor. Tactile sensor is fabricated by using micro- electro-mechanical-systems (MEMS). A common problem seen in the current tactile sensors that mimic the human skin are spatial resolution, sensing in a wide range and flexibility. Produced piezoelectric tactile sensor can be solution these problems. Piezoelectric polymer material is used for flexibility of tactile sensor. Nowadays, polyvinylidene flüoride (PVDF) is studied as a piezoelectric polymer in researches due to its excellent features like flexibility, workability and chemical stability. Otherwise, PVDF-TrFe, PVDF copolymers, is used in this work because it has ferroelectric properties without mechanical stretching at specific temperature. Piezoelectric tactile sensor need high quality film with thin, uniform, non-porous structure and also, deposited thin film in high quality that is necessary to deposit electrodes without causing short circuit. Therefore, PVDF-TrFe thin film is produced and characterized to obtain qualified thin film. Morphology of the films is analyzed by using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), differential scanning calorimeter (DSC), thermo gravimetric analyses (TGA). After morphological analyses, metal electrodes are deposited and patterned by using lift off technique. After that, micro polymer fiber arrays are grown on the electrodes with using lithography techniques. In general, micro polymer fibers are only used for adaptation of surface. When polymer fibers are integrated to tactile sensor, we get some solutions for common limitations. Finally, experimental setup is prepared for the tactile sensor calibration. Experiments are including response of micro polymer arrays of integrated tactile sensor and standard tactile sensor. As a result of experiments, micro polymer arrays of integrated tactile sensor have higher sensitivity than standard tactile sensor. Sensitivity of micro polymer arrays of integrated tactile sensor is computed 1.66 V/N and sensitivity of standard tactile is computed 0.94 V/N. Another experiment is about frequency response of micro polymer arrays integrated tactile sensor and this sensor is observed to be approximately stable up to 42 Hz frequency.