Control of flexible joint manipulators using only motor position feedback: A separation principle approach

We consider the problem of output feedback tracking of flexible joint manipulators where the link angle is the output to be controlled and the motor angle is the measured output. We allow the use of any globally stabilizing full state feedback control. We show recovery of the stability and trajectory performance of the state feedback by using a high gain observer-based output feedback control. Finally, we demonstrate the effectiveness of the proposed scheme in the single link case, where the zero dynamics are not asymptotically stable.