Hisanori Nakamura

Estimation of robot's life expectancy based on deterioration model and development of a CAE system

The burden of robot maintenance in the car industry (e.g. overhaul) is increasing drastically year after year. Although inspection and maintenance are indispensable in view of preventive maintenance, it is most important to accurately know the life expectancy of mechanical parts constituting a robot in order to execute the inspection and maintenance operations at the minimum investment. We therefore discuss the fact that the wear of gears is a dominant life expectancy factor of mechanical parts and we make observations on wear phenomenon in view of tribology. Based on the observations, we propose wear estimation models with improved lubrication and the improvement is applied to actual robots. In addition, we integrated the models with the robot off-line programming system and developed a CAE system capable of estimating the robot life expectancy at the time of preparation of robot teaching data.

Nanotechnologies of photonic crystals and quantum dots for ultrasmall and ultrafast all-optical switches

We have fabricated several two-dimensional photonic-crystal (2DPC) slab waveguides by using fine EB lithography and dry etching. The 2DPC waveguides include straight, bend and directional coupler on the GaAs/AlGaAs substrate as an application to the ultra-small and ultra-fast all-optical switching device (PC-SMZ). Site-controlled InAs quantum dots (QDs) responsible for nonlinear phase shift in the PC-SMZ have been investigated by developing a nano-probe assisted in-situ process. Optical linear and nonlinear properties of stacked QDs were characterized. The result exhibited the π/2 phase shift required for the SMZ-type optical switching operation. These results are capable of achieving the PC-SMZ.