Development of ladder climbing inspection robot with horizontal mobile function

In Japan, where earthquakes occur frequently, aging infrastructure such as bridges, chimneys, power lines and tunnels have become very severe concern. Aging infrastructure is extremely dangerous as it has possibility to collapse due to earthquake shaking. Therefore, it is necessary to find a dangerous point in infrastructures immediately to prevent accident. Inspection was mostly carried out by inspector climbing the attached ladders. However, the inspection climbing the ladder becomes dangerous, because it uses uncertain ladder and unpredictable weather and conditions occur. Based on the situation, the automatic ladder climbing inspection robot that can climb up and down the ladder by using flexible robot arms without giving damage to the ladder was developed in the previous study. The previous flexible robot arm that consists of three Extension type Flexible Pneumatic Actuators (EFPAs) that can extend about 2.5 times from its original length. In this study, as assuming investigations in hazardous environments where toxic / flammable gas exit or inside of a nuclear reactor, a ladder climbing inspection robot with horizontal mobile function was proposed and tested. The theoretical estimation for ladder climbing up motion of the robot based on the analytical model was carried out. As a result, it was confirmed that the tested robot could climb up the ladder, although only slightly. Also, the driving tests using the tested robot for ladder climbing down motion and horizontal mobile motion were also carried out. As a result, it was confirmed that the tested robot could realize both vertical and horizontal movements.