Control of a nonlinear two-mass system with uncertain parameters and unknown states

In this paper, three different kinds of position controls for a nonlinear two-mass system are presented. The control design for all three kinds directly takes the backlash into account. Uncertainties of parameters and nonlinear friction are also considered. The presented nonlinear control design is based on “exact linearization” in combination with an approximation of the backlash. The design results in three control structures, depending on whether the angle is measured at the drive side only, both sides or the load side only. Results of a test set-up are presented for the first two control structures. The third control structure has been tested in simulations