A projection method for simplifying robot manipulator models

Abstract

The equations of motion for a robotic manipulator are a very lengthy and complicated set of nonlinear, highly coupled differential equations. A simplified model that reveals the dominant dynamics would be valuable for purposes of utilizing modern control theory. In this work, a method is presented for obtaining a reduced model for a nonlinear system. The structure of the simplified model is assembled from a library of the nonlinear basis terms that were present in the original model. This p-term structure is selected from the library in p-stages using a recently developed optimization scheme based on projection matrices and conjugate direction ideas. The algorithm is used to identify the dominant dynamics of several robot manipulator models and the results are verified on the GCA P300V robot in RPI's Robotics and Automation Laboratory.