Inspection robot in complicated 3D environments

Half century ago, Japan started to increase her national wealth and to invest social infrastructures. Those activities could have accelerated its economy and brought further national wealth. Now spending many years almost all those facilities get old and are severely damaged. We started the limb mechanism project almost 20 years ago aiming at the robot application for rescuing as well as for inspection tasks in complicated 3D environments. We design and build first prototype, what we call ASTERISK, and demonstrated dexterous locomotion and manipulation capabilities including walk on ceiling underside, climbing up and down stairs and ladders, tightrope walk, and, of course, walk on rough terrains. Now we are applying our robot to attain the inspection of the underside of bridge. The robot has electro-magnetics at the tip of legs to approach and to access the underside. In the inspection task the robot has to walk around on side wall as well as underside, then to move from plane to plane. In the paper we will discuss the feasibility of walk on the underside of iron plate and the gait strategy in the transit from vertical plane to underside.