Model-Based Suppression Control for Liquid Vessels Carried by a Humanoid Robot While Stair-Climbing

This paper presents a study to evaluate the effects of sloshing phenomena while a humanoid robot climbs stairs while carrying water containers. Currently humanoid robots can perform a wide range of tasks including handling tools, climbing ladders, and patrolling rough terrain. However, when it comes to manipulation of objects humanoids are fairly limited. This becomes more apparent when humanoids have to handle non-rigid objects. Although many full-sized humanoids cost an extensive amount of money, they fail to respond to common tasks during disaster relief such as delivering water to the victims or possible fires. After disasters such as Hurricane Maria, the need for humanoid robots to assist in these scenarios is becoming increasingly evident. In previous work the authors have developed an algorithm which allows the robot to walk while carrying water buckets. Experiments conducted use the full-sized humanoid DRC-Hubo as an experimental platform. Moreover, a sloshing reduction controller is implemented in order to suppress rocking disturbances. The system was integrated via ROS (Robot Operating System). Additionally, the sloshing reduction was evaluated based on sensor data evaluation.