Attenuation of residual vibration of maneuvering structures is of interest in numerous applications such as hard disk drives, cranes, wafer scanning machines, space robots etc. Prefiltering the reference input to the underdamped system is a technique of achieving this objective. Motivated by the Posicast control technique, there have been numerous contributions related to the design of input prefilters which are robust to modeling uncertainties. These include ...
Time-Delay Filtering and Input Shaping
Input shaping involves design of a series of impulses to force the residual energy at the end of a maneuver to be zero and can include additional constraints which force the variation of the residual energy with respect to system parameters to zero, or which require the residual energy to be below a specified threshold for a certain region of uncertainty.
Time-Delay filtering involves design of a prefilter which cancels the underdamped poles of the system. Cascading these filters results in increasing the robustness of the prefilter to modeling uncertainties.
These techniques have been extended to address the problem of design of controllers where the cost function could represent the maneuver time, the fuel consumed, power consumed etc. Additional constraints on the magnitude of the permissible control and the rate of change of control (jerk) can be included in the design. This page includes reference to work carried out in the Dept. of Mechanical and Aerospace Engineering at the State University of New York at Buffalo.