Recent decades have been witness to explosive leaps in manufacturing productivity. Advances in communication technology, computing speed, control theory, and sensing technology have been significant contributors toward the increased productivity and efficiency that industry has exhibited. The continued growth of technological equipment and engineering knowledge challenges engineers to fully utilize these advancements in more sophisticated and useful automation systems. One such application involves enhancing bridge and gantry crane operation. These systems are used throughout the globe, and are critical aspects of industrial productivity. Consequently, improving the operational effectiveness of cranes can be extremely valuable. Effective control of cranes can be largely attributed to two distinct, but related aspects crane manipulation: 1) the expertise of operators, which are responsible for issuing commands to the structures, and 2) the dynamic properties of cranes, which influence how the structures respond to issued commands. Accordingly, the operational efficiency of cranes can be influenced by changing both the way that operators issue commands to cranes, and also how the crane responds to issued commands. This thesis is concerned with dynamic control theory of flexible machines, and human/machine interaction, especially as these areas relate to industrial crane control. In the area of dynamic control, this thesis investigates control strategies that are specifically suited for use on systems that possess common actuator nonlinearities, like saturation, rate limiting, dead-zone, backlash, and finite-state actuation. In the area of human/machine interaction, this thesis investigates the effects of different crane interface devices on the operational efficiency of cranes.

A helicopter can be used to transport a load hanging from a suspension cable. This technique is frequently used in construction, firefighting, and disaster relief operations, among other applications. Unfortunately, the suspended load swings, which makes load positioning difficult and can degrade control of the helicopter. This dissertation investigates the use of input shaping (a command-filtering technique for reducing vibration) to mitigate the load swing problem. The investigation is conducted using two different, but complementary, approaches. One approach studies manual tracking tasks, where a human attempts to make a cursor follow an unpredictably moving target. The second approach studies horizontal repositioning maneuvers on small-scale helicopter systems, including a novel testbed that limits the helicopter and suspended load to move in a vertical plane. Both approaches are used to study how input shaping affects control of a flexible element (the suspended load) and a driven base (the helicopter). In manual tracking experiments, conventional input shapers somewhat degraded control of the driven base but greatly improved control of the flexible element. New input shapers were designed to improve load control without negatively affecting base control. A method for adjusting the vibration-limiting aggressiveness of any input shaper between unshaped and fully shaped was also developed. Next, horizontal repositioning maneuvers were performed on the helicopter testbed using a human-pilot-like feedback controller from the literature, with parameter values scaled to match the fast dynamics of the model helicopter. It was found that some input shapers reduced settling time and peak load swing when applied to Attitude Command or Translational Rate Command response types. When the load was used as a position reference instead of the helicopter, the system was unstable without input shaping, and adding input shaping to a Translational Rate Command was able to stabilize the load-positioning system. These results show the potential to improve the safety and efficiency of helicopter suspended load operations.