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Reproducing the capabilities of the human sense of touch in machines is an important step in enabling robot manipulation to have the ease of human dexterity. A combination of robotic technologies will be needed, including soft robotics, biomimetics and the high-resolution sensing offered by optical tactile sensors. This combination is considered here as a SoftBOT (Soft Biomimetic Optical Tactile) sensor. This article reviews the BRL TacTip as a prototypical example of such a sensor. Topics include the relation between artificial skin morphology and the transduction principles of human touch, the nature and benefits of tactile shear sensing, 3D printing for fabrication and integration into robot hands, the application of AI to tactile perception and control, and the recent step-change in capabilities due to deep learning. This review consolidates those advances from the past decade to indicate a path for robots to reach human-like dexterity., Comment: 13 pages. Accepted, IEEE Sensors

We report on a new, single-step and scalable method to fabricate highly ordered, multi-directional and complex surface structures that mimic the unique morphological features of certain species found in nature. Biomimetic surface structuring was realized by exploiting the unique and versatile angular profile and the electric field symmetry of cylindrical vector (CV) femtosecond (fs) laser beams. It is shown that, highly controllable, periodic structures exhibiting sizes at nano-, micro- and dual-scale micro and nano scales can be directly written on Ni upon line and large area scanning with radial and azimuthal polarization beams. Depending on the irradiation conditions, new complex multi-directional nanostructures, inspired by the Shark skin morphology, as well as superhydrophobic dual-scale structures mimicking the Lotus leaf water repellent properties can be attained. It is concluded that the versatility and features variations of structures formed upon scanning with CV beams is by far superior to those obtained via laser processing with linearly polarized beams. More important, by exploiting the capabilities offered by fs CV optical fields, the present technique can be further extended to fabricate even more complex and unconventional structures. We believe that our approach provides a new concept in laser processing of materials, which can be further exploited for expanding the breadth and novelty of potential applications.

Carbon fibres (CF) represent a significant volume fraction of modern structural airframes. Embedded into polymer matrices, they provide significant strength and stiffness gains over unit weight as compared to other competing structural materials. Nevertheless, no conclusive structural model yet exists to account for their extraordinary properties. In particular, polyacrynonitrile (PAN) derived CF are known to be fully turbostratic: the graphene layers are slipped sideways relative to each other, which leads to an inter-graphene distance much greater than graphite. Here, we demonstrate that CF derive their mechanical properties from those of graphene itself. By monitoring the Raman G peak shift with strain for both CF and graphene, we develop a universal master plot relating the G peak strain sensitivity of all types of CF to graphene over a wide range of tensile moduli. A universal value of - average- shift rate with axial stress of ~ -5{\omega}0^-1 (cm^-1 MPa^-1)is calculated for both graphene and all CF exhibiting annular ("onion-skin") morphology., Comment: 25 pages, 5 figs