Adhesion Force Control and Active Gravitational Compensation for Autonomous Inspection in LPG Storage Spheres

This paper presents a climbing robot based in wheel locomotion and magnetic adherence, a common mechanical topology applicable to a wide range of industrial tasks. The robot is applied to perform internal/external inspection in liquefied petroleum gas (LPG) storage spheres, hence, some severe operation features like adherence and force balance impose necessary conditions to the robot. In order to satisfy these conditions, a dynamic control system is developed in two steps, active gravitational compensation and adhesion force control.