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Pressure perception is an important element for robot tactile sensing. We developed a two-range pressure sensor based on fiber Bragg grating (FBG) that can detect slight pressure with higher sensitivity, and can also adapt to a larger range of forces to sense. The sensor was designed by nesting two elastomers, which convert the pressure signal into a displacement signal and then turn into wavelength information under the processing of the bottom FBG that wrapped in silicone. This design makes the robot to cope with more complex and changeable environments. Moreover, the sensor unit has strong anti-interference ability which is applied to complex robot skin array sensing systems, because it is located in the inner layer that is divided into sensing part and signal processing part. This ranged sensor with three-layer elastomer has crucial practical significance for robot tactile.

This paper introduces a novel shape and texture recognizing technique based on the design of bionic whisker. Whisker arrays are installed on both sides of the robot. In the experiment, the whisker sweeps around to detect the unidentified object. The center wavelength of fiber Bragg grating (FBG) pasted on the whisker shifts when the whisker touches the obstacle. Shape recognition is realized by processing and further calculating the wavelength shift data. At the same time, the whisker sweeps over the surface texture, and the texture information is obtained by processing the wavelength shift data with the time-frequency analysis method. The results show that the whisker sensor can identify the three-dimensional profile shapes of contacted objects and the texture features of touched surfaces effectively. K: Data analysis; Detector design and construction technologies and materials 1Corresponding author.

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Force/strain sensitivity and fringe contrast are important parameters of spheroidal Fabry-Perot interferometers (FPIs). A static structural model and a ray optics model are proposed in this paper for analyses of force/strain sensitivity and fringe contrast. The models proposed show that the sensitivity and fringe contrast of FPIs with spheroidal cavities can be controlled through the dimensions of the spheroids. To corroborate the analyses, three spheroidal FPIs are fabricated via a chemical etching method and static force experiments are carried out. The maximum relative errors of force sensitivity and fringe contrast are 5.2% and -6.4%, respectively. We believe that this research will contribute to improvements in the performance of spheroidal FPIs.