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Input shaping is an effective means of eliminating vibration in many types of flexible systems. This paper discusses how input shaper performance is affected by a fixed acceleration limit. This type of limit is a common occurrence in many mechanical drive systems because it corresponds to a constant force or torque input. It is shown that some input shapers are not affected by an acceleration limit under certain conditions. A test criterion is developed to determine what types of input shapers are negatively affected, and a method is proposed to compensate for the detrimental effects of the constant acceleration limit. Experimental results from an industrial crane support the main theoretical results.

The conventional unity magnitude zero vibration (UM-ZV) command shaping technique is an effective means for eliminating vibration in linear mechanical systems with on-off actuators. This paper discusses how the UM-ZV command shaping technique is affected by a common nonlinearity: nonsymmetrical accelerating and braking dynamics. Two approaches for creating new types of UM-ZV shaped commands are presented: a closed-form analytic solution and a numerical optimization approach. Both methods reduce residual vibration of the nonlinear system more effectively than the conventional UM-ZV shaped commands. Simulations and experiments on a bridge crane confirm the effectiveness of the new commands.

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Cranes provide an excellent platform for teaching advanced controls. They have a simple pendulum-type oscillation that is useful for demonstrating basic control methods. However, cranes also have additional dynamic effects such as motor dynamics, velocity limits, and nonlinear slewing dynamics that make them well suited for advanced study. If the cranes are made remotely operable, then students can also study tele-operation and control of systems with time delays. An advanced control design course taught at the Georgia Institute of Technology has integrated tele-operated cranes into both the lecture and laboratory exercises. The laboratories lead the students through the use of two tele-operated cranes. The lab component of the course culminates with a five-week team project in which the students design and implement their own research project on the cranes. The primary goal of using the cranes is to provide hands-on experiences in implementing advanced controllers on real systems. This paper describes the cranes and the complementary curriculum.