Control of linear second-order systems by fuzzy logic-based algorithm

The control of flexible structures employing the passivity approach has bee n extended to systems having noncollocated input/output pairs by introducin g all observer that incorporates the nominal dynamical model of the plant. The passive observer-based control is applied to the American Control Confe rence benchmark problem, whereby; the control force emulates a dynamic vibr ation absorber attached to a virtual wall with passive control elements (sp ring, mass, and dashpot). The springs and mass elements of the controller a re constant, whereas the damping coefficients are selected as time dependen t ill all attempt to choose continuously the most appropriate amount of dum ping in compliance with the design goals, A novel approach is introduced, w hereby the passive observer-based control law is modified by varying the da mping coefficient of the virtual dashpot by means of an adaptive fuzzy logi c algorithm. This modified system exhibits quick settling times and desirab le performance characteristics. Results from the statistical robustness ana lysis for the developed controller are compared to 10 other (linear) soluti ons of the benchmark; problem. The comparison is based on robust stability robust performance (settling time), and control effort, The results obtaine d by the adaptive fuzzy logic algorithm are superior to those obtained by a ll other methods, and, consequently, further application of the fuzzy algor ithm is advocated.