CONTROL SYSTEMS DESIGN FOR MULTIVARIABLE SYSTEMS WITH MULTIPLE TIME DELAYS.

摘要

The control problem posed by the presence of multiple time delays is solved by introducing a compensator which eliminates the delays from the system characteristic equation. The resulting controller (structurally similar to the linear quadratic optimal feedback controller) is demonstrated to be very effective as well as easy to implement and reduces to the well known Smith Predictor (and Moore Predictor) for the special case of a single time delay.; This design technique is incorporated into a computer-aided control systems design package for handling processes with multiple time delays without using polynomial approximations for the irrational e('-(tau)s) function. The package also provides dynamic simulations for the purpose of evaluating controller performance.; Through the introduction of operator matrices and the partioning of the state vector space, a new approach to the design of stable observers for general time delay systems is developed. A judicious resolution of the state vector into two component vectors allows one to make an appeal to standard, finite-dimensional Luenberger theory thus restoring the desired situation in which the observer eigenvalues can be designer-specified. Open- and closed-loop performances of the observer are demonstrated and its application to multidelay compensation explicitly presented.; The theoretical developments are experimentally evaluated on a pilot scale binary distillation column. The performance under traditional single loop PI control is compared with performance using the delay compensator in response to set point changes and disturbances.