A partial state feedback controller for tajectory tracking of rigid‐link fiexible‐joint robot using an observed backstepping approach

This article presents a partial state feedback controller for a rigid‐link flexible‐joint (RLFJ) robot using an observed integrator backstepping approach. The robot controller requires only link position and actuator position measurements, and eliminates the need for measuring link velocity and actuator velocity. The controller uses two exact knowledge, second‐order nonlinear observers to estimate the link and actuator velocities. The overall control system achieves a semiglobal exponential stability result for the link position and velocity tracking errors as well as the velocity observation errors. A stability proof and simulation results for the proposed partial state feedback controller are included in the article. © 1995 John Wiley & Sons, Inc.