Abstract
The main objective of this work is to investigate a causal inverse dynamics of a flexible single hub-arm system with a variable tip mass and to control the end point motion. The joint trajectory was assumed and the end point trajectory was obtained directly through the solution of the inverse dynamic problem. Although the flexible link is nonminimum phase in nature, the use of feedforward torque with end point acceleration feedback gives very good performance specially for variable tip mass. A robust controller was designed for tracking the desired trajectory based on classical control methodologies.