Hand-motion crane control using radio-frequency real-time location systems

Human operators have difficulty driving cranes quickly, accurately, and safely because the heavy structure of the crane responds slowly and its payload oscillates. Manipulation difficulty is increased by nonintuitive control interfaces (such as buttons, levers, and joysticks) that require substantial experience to master. This paper presents a new type of interface that allows operators to drive a crane by simply moving a hand-held radio-frequency tag through the desired path. Real-time location sensors are used to track the movements of the tag and its position is used in a feedback control loop to drive the crane. Unfortunately, crane movements usually induce large-amplitude payload oscillations. Therefore, an input-shaping control element is used to limit payload swing. Experimental results on an industrial bridge crane validate the controller performance.