Digital implementation of non-integer control and its application to a two-link robotic arm

This paper assesses relative merits and drawbacks of different digital implementations of non-integer order controllers. Twenty-eight formulas are considered. Their frequency behaviours, together with those of discretised CRONE controllers, are compared to the ideal ones. All those formulas are used for implementing controllers found in the literature for a robotic arm. Backward finite difference formulas, Tustin formula and a zero order hold discretisation of a CRONE controller achieve the best results.