Modeling Human-Structure Interaction Using Control Models When Bobbing on a Flexible Structure

Abstract

High performance materials has enabled engineers to design civil structures with smaller dead loads than in the past. However, lower dead loads results in a higher live to dead load ratio and the possibility of excessive vibrations due to human loading. This paper extends a controller theory based model to model the human-structure-interaction (HSI) problem. Prior work focused on modeling a standing individual with bent knees using a proportional, integrative and derivative (PID) controller model. This work extends this idea to a person bobbing or performing short movement up and down by bending his or her knees at the frequency provided by a metronome. Prior work considered the input to the human-structure system was a force applied to the structure. This work consider the bit produced by a metronome as the input to the overall human-structure system. The force applied to the structure is modeled as the output of the human, while the structure’s acceleration is fed back into the control human system. Experiments performed at the University of South Carolina using a flexible platform that behaves as a single degree of freedom system are used to test the model. A force plate is installed in the platform to measure the forces exerted by the person on the platform as he or she moves. Model parameters and their corresponding uncertainty are quantified in a probabilistic fashion using Bayesian inference with the force plate forces as well as the acceleration measurements of the structure as observations. The model performance is evaluated by comparing probabilistic predictions with force and acceleration measurements found experimentally.