Aulomatirn and Robotics in Construction XVI Swing-Free Cranes via Input Shaping of Operator Commands

Kenneth Groom, Gordon Parker, Rush Robi
unpublished
I Abstract This paper presents an open-loop control method for suppressing payload oscillation or swing caused by operator commanded maneuvers in rotary boom cranes and the method is experimentally verified on a one-sixteenth scale model of a Haggluncls shipboard crane. The crane configuration consists of a payload mass that swings like a spherical pendulum on the end of a lift-line which is attached to a boom capable of hub rotation (slewing) and elevation (luffing). Positioning of the payload
more » ... ning of the payload is accomplished through the hub and boom angles and the load-line length. Since the configuration of the crane affects the exci-tation and response of the payload, the swing control scheme must account for the varying geometry of the system. Adaptive forward path command filters are employed to remove components of the command signal which induce payload swing. moving supplies ashore in the absence of port facilities. The keystone of the system will be boom cranes mounted on a dedicated ship, which will move cargo from container ships to lighterages, small landing craft, for transport to shore. See Figure 1. 2 Introduction A recent trend for the U.S. Navy is to reduce the number of its auxiliary ships, those used for supply, and instead rely on commercial ships for logistical support. The commercial shipping industry, however , has been moving toward high speed, non-self-sustaining container ships which in general require large cranes to handle its containers. Military operations , as well as disaster relief operations, are often conducted on undeveloped beaches and response time often precludes the construction of port facilities. The Navy's Container Offloading and Transfer System (COTS) is currently under development to address the problem of offloading container ships and Figure 1: Crane ship transferring cargo from container ship to lighter Lack of a protective harbor during these operations subjects the crane ships to wave activity which results in undesirable oscillations, or swinging, of the container. Sandia National :Labs is currently developing crane control methods to eliminate unwanted payload swing in sea state three like conditions. A critical component of this control system is a filter for preventing swing induced by the operator's commands. This paper presents an open-loop control method for suppressing payload swing caused by operator commanded maneuvers in rotary boom cranes and the method is experimentally verified on a one-sixteenth scale model of a Haggluncls shipboard 417
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