Repetitive-predictive control of a robot arm with constraints

A multivariable predictive-repetitive controller was developed by the authors in their recent work, which uses a frequency response decomposition technique to detect the dominant frequency components in the reference signals and embeds these components in the predictive-repetitive controller. This paper presents new experimental results on a robot arm configured as a two inputs and two outputs system, which demonstrate the closed-loop performance of the predictive-repetitive control system in terms of reference trajectory following, disturbance rejection andmeasurement noise attenuation. Furthermore, it is shown that the bandwidth of the predictive repetitive control system is strongly depending on the number of frequencies embedded in the design. The larger the number of frequencies, the wider the bandwidth of the closed-loop system. As a result of wider bandwidth, measurement noise is amplified and unmodelled dynamics in the higher frequency band could cause the closed-loop system to become unstable