“…To that end, the focus has been on developing wheeled robots [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ], flying robots [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ], and snakelike robots [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Many recent studies focus on developing not only robots that perform risky or difficult tasks for humans, but also production robots in workplaces that face labor shortages [ 27 , 28 , 29 , 30 ], cleaning robots to support housework to meet the demands of our busy lives [ 31 , 32 , 33 , 34 , 35 ], and robots to support the medical sector. Besides fixed robots (e.g., arm robots), most robots move and perform tasks in a wide range of environments; if robots have a wide range of movement, their large size does not constitute a problem.…”