An Automatic Verification of Simplified Robot Models

Abstract

The computer program ALMORO has been implemented by the author in 1987 to generate symbolically the forward solution and the complete Lagrangian dynamic robot model. The derived closed—form equations could become even extremally complex — especially for more complicated manipulators. At the same time model—based controllers require the on—line evaluation of the robot dynamics in the control law. This becomes computationally expensive and time—consuming task and often dictates the use of numerically simplified models. It also turned out that the simplification procedure applied without accounting some specific model properties (configuration dependence, interrelationships etc.) can violate the fundamental physical principles and destroy the structure of the controller. The objective of the present paper is to demonstrate a method of model simplifications based on systematic approach to simplification process. The complete closed—form robot models are simplified automatically using a set of symbolically generated simplification strategies. The author has expanded the capabilities of ALMORO to include the operations necessary for systematic simplification procedure.