Control of Robotic Crawler Cranes in Tandem Lifting Operations

Abstract

Moving heavy and over-sized loads poses significant control challenges. A single crawler crane may be insufficient for such lifting tasks if the payload exceeds the capacity, or if the payload’s size and shape make it difficult to secure it to a single crane hook. To solve these problems, it may be necessary to manipulate such items by tandem lifting with two cranes. These cranes are usually driven by two operators whose actions are coordinated by a lift director. In this paper, a pseudo-dynamic model describing the behavior of such a system, when the bases of the cranes are moving in a straight line, is derived. The paper also sets basic guidelines that prevent tip-over accidents. Finally, it presents a control system that eliminates the need for a second crane operator by making one crane mimic the behavior of the other crane, thus reducing the possibility of human errors.