In this paper, we present an approach for navigating a robotic wheelchair that provides users with multiple levels of autonomy and navigation capabilities to fit their individual needs and preferences. We focus on three main aspects: (i) egocentric computer vision based motion control to provide a natural human-robot interface to wheelchair users with impaired hand usage; (ii) techniques that enable user to initiate autonomous navigation to a location, object or person without use of the hands; and (iii) a framework that learns to navigate the wheelchair according to its user’s, often subjective, criteria and preferences. These contributions are evaluated qualitatively and quantitatively in user studies with several subjects demonstrating their effectiveness. These studies have been conducted with healthy subjects, but they still indicate that clinical tests of the proposed technology can be initiated.

Nonferrous materials such as copper and its alloys are sensitive to seawater corrosion. In this work, a hydrothermal carbonization coating was deposited on a C26000 brass and pure copper. The effectiveness of the coating on improving seawater corrosion performance was examined. First, hydrothermal carbonization of sugar (with 10 wt.% sucrose in water) at 200 °C and 1.35 MPa for 4 h was performed to generate the carbon-rich coating. The results of surface morphology, composition, hardness, thickness, and wettability to seawater were presented. Then, the corrosion resistance of the brass and pure copper with and without coating was evaluated by measuring the Tafel constants in seawater. Important parameters including the corrosion current, potentials of corrosion, and polarization resistance for the brass and pure copper with and without the coating were calculated from the polarization measurement data. It was found that the hydrothermal carbonization of sugar produced a relatively dense carbon-rich layer on the surface of the copper and brass specimens. This carbon layer has a thickness of 120 µm, and it is highly corrosion resistant. The corrosion current of the copper and its alloy in seawater is reduced significantly through the hydrothermal carbonization treatment. The carbonized coating reduced the corrosion current obviously, but only resulted in a small positive shift of 0.05–0.1 V in the corrosion potentials. The hydrothermally produced carbon layer is just like a passivation coating on the pure copper and copper alloy to slow down their corrosion rates in seawater.