First generation scalar CRONE control: application to a two DOF manipulator and comparison with non linear decoupling control

The dynamic model of a robot manipulator is described by a set of nonlinear, highly coupled differential equations. Linear control schemes (namely PD or PID independent joint controllers) are often used, the manipulator being regarded as a set of linear independent dynamic systems with the nonlinear and coupling effects acting as disturbances. The performance of these simple schemes greatly deteriorates in the presence of uncertainty (e.g. payload variations), or if dynamic effects are not negligible as when tracking of high-speed, high-acceleration trajectories is required. The paper discusses the application of the CRONE concept to the robust control of a two degree of freedom (DOF) manipulator. CRONE is the French abbreviation for “Commande Robuste d´Ordre Non Entier” (NonInteger Order Robust Control). Such a control is based on the noninteger derivative operator. The control performances are evaluated and compared to those obtained with the nonlinear decoupling control. The obtained results show the good performances of the CRONE control proving control scheme can be a valid alternative model based control algorithms