Constrained Optimization for Hierarchical Control System Design
Abstract
This thesis presents a constrained convex optimization control design procedure that takes advantage of a decoupled hierarchical system structure. To achieve a hierarchical structure, a system is decoupled into primary channels that have its own dynamics, control actuator, and a resulting controller. These MIMO (multiple input/multiple output) channels are then decoupled into a hierarchical structure of SISO (single input/single output) loops. The constrained optimization procedure is then applied to each SISO loop to determine a solution controller. The procedure minimizes the closed loop H2 norm as the primary objective, while presenting the Q-minimization objective as a secondary option. The procedure applies closed loop frequency and transient response constraints to the constrained optimization, which utilizes Q-parameterization of the objective function. The Q-parameter optimization decision variables are the coefficients of a stable orthogonal basis. This basis is constructed using a presented Basis Function Algorithm, designed as a consistent procedure for basis selection. The algorithm is designed to create the most efficient basis from three forms of basis functions: Finite Impulse Response (FIR) functions, Laguerre functions, and Legendre functions. User defined Fixed Pole Model basis functions are also addressed. The design method is applied using the Draper Laboratory's Structural Control Toolbox (SCTB), a Computer Aided Design (CAD) tool. The design procedure is used on the Draper Small Autonomous Aerial Vehicle (DSAAV) helicopter as a design example. The solution procedure was able to make improvements in the design of the DSAAV forward motion channel. This design utilized the modularity of the hierarchical structure, using both constrained optimization and classical controller designs.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 25, 1999
- Accession Number
- ADA370665
Entities
People
- Michael B. Jamoom
Organizations
- Air Force Institute of Technology