Local Control Design Methodologies for a Hierarchic Control Architecture

Jonathan P. How and Steven R. Hall


Abstract

The problems associated with the control of large intelligent space structures with many sensors and actuators have previously led to the development of a hierarchic control architecture. This control arrangement consists of a two level combination of a centralized global controller and a set of local controllers which are distributed to complement the dynamic behavior of the structure. Four decentralized control methodologies which are suitable for implementation at the lower level of the hierarchic architecture are developed and analyzed in this thesis.

The first design only allows colocated feedback. The second design allows feedback from within a region of the structure. The third allows communication between adjacent local controllers so that information from neighboring regions can be used for the feedback. The last employs a distributed implementation of the full state feedback. The simulation results for the control of a long beam in bending show that employing the more complicated decentralized designs at the lower level of the hierarchic architecture will slightly improve the overall performance. However, the implementation costs for these more sophisticated designs are shown to increase dramatically. The most efficient hierarchic design for this beam example is one which combines a good global design with a simple colocated feedback. This conclusion may change for structures which require more performance at the local level.


Serc Report #3-90, Feb. 1990

Local Control Design Methodologies for a Hierarchic Control Architecture