VIBRATION REDUCTION USING MULTI-HUMP INPUT SHAPERS

Input shaping is a method for reducing residual vibrations in computer -controlled machines. Vibration is eliminated by convolving an input s haper, which is a sequence of impulses, with a desired system command to produce a shaped input. The shaped input then becomes the command t o the system. Requiring the vibration reduction to be robust to modeli ng errors and system nonlinearities is critical to the success of the shaping process on any real system. Input shapers can be made very ins ensitive to parameter uncertainty; however, increasing robustness usua lly increases system delays. A design process is presented that genera tes input shapers with insensitivity-to-time-delay ratios that are muc h larger than traditionally designed input shapers. The advantages of the new shapers are demonstrated with computer simulations and their p erformance is verified with experimental results from the MIT Middeck Active Control Experiment, which was performed on board the Space Shut tle Endeavor.