Trends in the Stability Properties of CLSS Controllers: A Root-Locus Analysis

The control of flexible systems includes a variety of control strategies that are implemented via numerous architectures (open-loop control, feedback loops, etc.). One useful form of vibration control is input shaping. Traditionally, input shaping is an open-loop control strategy utilizing the destructive interference of vibration waves to eliminate oscillations. However, some research has advanced the traditional use of input shaping by utilizing it within feedback loops. This paper focuses on the closed-loop stability of feedback loops containing input shapers by analyzing their dynamics via root locus plots. Experimental results on an industrial bridge crane support the theoretical conclusions.