Vertical motion control of building façade maintenance robot with built-in guide rail

Recently, the number of high-rise building has increased along with the development of technology to cope with the increase in population. Because of this, many researches on an automatic building façade maintenance system have been conducted to satisfy the increasing demands of façade maintenance. However, most researches have focused on the mechanism and system composition, while working safety issues have not been sufficiently dealt with. This paper deals with the motion control issues of the building façade maintenance robot system which is composed of a vertical robot and a horizontal robot moving along the rail of the façade. With consideration for the vertical robot, these issues include the safety of docking process and the stability of vertical motion. During the docking process for the inter-floor circulation of the horizontal robot, shocks and positioning errors are generated due to increasing load. To solve this, the rail brake system is operated to suppress the shock during the docking process, and a re-leveling process is conducted to compensate the gap which is equal to the positioning error between the built-in transom rail of the robot and the transom rail of the building. In addition, many noises are generated from the surroundings that significantly affect the motion of the vertical robot due to vibration. To enhance the motion stability of the vertical robot, vibration suppression control is developed in this paper, using the state estimation which considers the dynamic properties of the wire rope. For the feasibility of this algorithm, the field experiment of the building façade maintenance robot is conducted.