A capacitive tactile sensor array for surface texture discrimination

A tactile-based fabric learning and classification architecture

“…It consists of a Cartesian robot equipped with a force/torque sensor used to measure the pressure exerted on fabrics, which are located on a horizontal plate. The Cartesian robot is a 5 DoF system with independent x, y and z-linear axis, as well as two rotating angles along the x and y-axis, which are actuated using high-precision motorised stages from ThorLabs 1 . The x and y-axis, as well as one rotational motor, move an instrumented platform where fabrics are fixed for all the experiments.…”

“…Providing robot with the capability of manipulating and recognising fabric is still a challenging task. Indeed a huge effort has been done in literature in order to classify various kinds of materials (polycotton, nylon, silicone, brass, wood plastic, foam, and PVC to name, but few) using tactile sensors based on different transduction principles [1], [2], [3] but with respect to the these examples, where materials have clear different geometric and mechanical characteristics, to classify fabrics is more challenging due to the high variability of existing types that in many cases could have really similar characteristics (i.e., consider for example a jumper that can be made from wool or acrylics). A multisensorial approach can be used for improving the fabric classification as in [4], where data coming from RGB-D, tactile, and photometric stereo sensors are used, but when only one sensor modality is available, the challenge is to find a fabric exploration technique that allow to detect all its discriminative characteristics and also to determine which are the sensor data features that are most effective for discriminating the different type of fabrics.…”

Dynamic Tactile Sensing

“…With sufficient response, small arrays of piezoresistive or capacitive sensors can also be used in a scanning mode, to discriminate among different textures [43][44][45][46] or to detect incipient object slippage based on the ratios of strains as an elastic fingertip is pressed against a surface and loaded in shear [47]. Optical tactile sensors can also detect changing textures and slip, depending on the frame rate of the associated optical imaging device [48].…”

Highly Sensitive Soft Tactile Sensors for an Anthropomorphic Robotic Hand

“…In order to cope with this increasingly pressing demand, over the past thirty years many tactile sensors have been proposed (see [7] for an extensive review, up to the year 2010). Even just during the last five years, a considerable number of solutions have been proposed, employing many different technologies: capacitive [8]- [11], optical [12], [13], piezoresistive [14]- [16] (see [17] for a recent review), piezoelectric [18]- [20], ultrasonic [21], magnetic [22]- [24], nanoparticles [25], carbon nanotubes [26], [27], conductive liquids [28]- [30], conductive polymers [31] and tunnel effect [32]. Unfortunately, only a few of these technologies have been tested in actual robots, and therefore it is not easy to evaluate to what extent the data extracted from these sensors is useful for robotic applications.…”