An Analysis of Observed-System Sensitivity to Plant Parameter Variations.
Abstract
State-variable feedback is a modern control theory technique that is employed in system design to place closed-loop poles to achieve desired performance characteristics. Two problems associated with state-variable feedback are physical inaccessibility to plant states and output sensitivity to plant parameter variations. In this report an observer is employed to reconstruct all plant states. The plant-observer system is investigated with respect to sensitivity aspects of the following three areas: state-variable representation, extent of pole placement, and observer dynamics design. A comparison between physical, phase, and Jordan canonical variables indicated physical and phase variable representations yield identical sensitivity functions; Jordan canonical variables result in greater sensitivity than physical and phase variables. Placing plant poles close together creates a high system sensitivity to plant parameter variations; separation of poles reduces sensitivity. As a minimal requirement for low system sensitivity, observer poles should be placed to the left of dominant plant poles; further reductions in sensitivity are achieved by placing observer poles to the left of all plant poles. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1978
- Accession Number
- ADA055190
Entities
People
- Dennis Larry Hamme
Organizations
- Air Force Institute of Technology