2-STAGE STRATEGY FOR SIMULTANEOUS SLEWING AND VIBRATION SUPPRESSION OF FLEXIBLE STRUCTURES

This paper presents an open loop near-minimum-time solution for simult aneous slewing and vibration suppression of flexible structures. The p roblem is formulated as an open-loop, minimum-system energy and/or con trol effort optimal control problem in modal space. With parametric co ntrol law, a two-level problem-solving strategy is presented. In the f irst stage, a sequence of rigid mode-based time-optimal control proble ms is solved and the minimum maneuver time is found by gradually reduc ing the maneuver time until the solution converges. In the second stag e, the optimal parameters of the control law are evaluated using nonli near programming with prescribed performance index as its objective fu nction. The proposed strategy, through time-optimal control of the rig id mode combined with the parametric quadratic control of the elastic modes, determines the control profiles which give both minimum maneuve r time and desired value of performance index. As an example, the opti mal control of a slewing flexible beam is presented, and high performa nce slewing maneuver is achieved.