Closed-loop Reference Models for Output-Feedback Adaptive Systems

Closed-loop reference models have recently been proposed for states accessible adaptive systems. They have been shown to have improved transient response over their open loop counter parts. The results in the states accessible case are extended to single input single output plants of arbitrary relative degree.Comment: v1 Submitted to European Control Conference 2013, v2 Typos correcte

Connections Between Adaptive Control and Optimization in Machine Learning

This paper demonstrates many immediate connections between adaptive control and optimization methods commonly employed in machine learning. Starting from common output error formulations, similarities in update law modifications are examined. Concepts in stability, performance, and learning, common to both fields are then discussed. Building on the similarities in update laws and common concepts, new intersections and opportunities for improved algorithm analysis are provided. In particular, a specific problem related to higher order learning is solved through insights obtained from these intersections.Comment: 18 page

Psychobiological factors of resilience and depression in late life.

In contrast to traditional perspectives of resilience as a stable, trait-like characteristic, resilience is now recognized as a multidimentional, dynamic capacity influenced by life-long interactions between internal and environmental resources. We review psychosocial and neurobiological factors associated with resilience to late-life depression (LLD). Recent research has identified both psychosocial characteristics associated with elevated LLD risk (e.g., insecure attachment, neuroticism) and psychosocial processes that may be useful intervention targets (e.g., self-efficacy, sense of purpose, coping behaviors, social support). Psychobiological factors include a variety of endocrine, genetic, inflammatory, metabolic, neural, and cardiovascular processes that bidirectionally interact to affect risk for LLD onset and course of illness. Several resilience-enhancing intervention modalities show promise for the prevention and treatment of LLD, including cognitive/psychological or mind-body (positive psychology; psychotherapy; heart rate variability biofeedback; meditation), movement-based (aerobic exercise; yoga; tai chi), and biological approaches (pharmacotherapy, electroconvulsive therapy). Additional research is needed to further elucidate psychosocial and biological factors that affect risk and course of LLD. In addition, research to identify psychobiological factors predicting differential treatment response to various interventions will be essential to the development of more individualized and effective approaches to the prevention and treatment of LLD

Adaptive Output-Feedback Control for A Class of Multi-Input-Multi-Output Plants with Applications to Very Flexible Aircraft

A dominant presence of parametric model uncertainties necessitates an adaptive approach for control of very flexible aircraft (VFA). This paper proposes an adaptive controller that includes a baseline design based on observers and parameter adaptation based on a closed-loop reference model (CRM), and is applicable for a class of multi-input multi-output (MIMO) plants where number of outputs exceeds number of inputs. In particular, the proposed controller allows the plant to have first-order actuator dynamics and parametric uncertainties in both plant and actuator dynamics. Conditions are delineated under which this controller can guarantee stability and asymptotic reference tracking, and the overall design is validated using simulations on a nonlinear VFA model.Boeing Strategic University Initiativ

Supplementary Materials to "Adaptive Output-Feedback Control for A Class of Multi-Input-Multi-Output Plants with Applications to Very Flexible Aircraft"

A dominant presence of parametric model uncertainties motivates an adaptive approach for control of very flexible aircraft (VFA). This paper proposes an adaptive controller that includes a baseline design based on observers and parameter adaptation based on a closed-loop reference model (CRM), and is applicable for a class of multi-input multi-output (MIMO) plants where number of outputs exceeds number of inputs. In particular, the proposed controller allows the plant to have first-order actuator dynamics and parametric uncertainties in both plant and actuator dynamics. Conditions are delineated under which this controller can guarantee stability and asymptotic reference tracking, and the overall design is validated on a nonlinear VFA model.Boeing Strategic University Initiative

Squaring-Up Method for Relative Degree Two Plants

Abstract--- Non-square multi-input-multi-output (MIMO) plants are becoming increasingly common, as the addition of multiple sensors is becoming prevalent. However, square systems are needed sometimes as an leverage when it comes to design and analysis, as they possess desirable properties such as strict positive realness. This paper presents a squaring up method that adds artificial inputs to a class of MIMO plants with relative degree two and stable transmission zeros, where number of outputs exceeds number of inputs. The proposed method is able to produce a square plant that has stable transmission zeros and uniform/nonuniform relative degree, and is used to carry out adaptive control of this class of plants and shown to lead to satisfactory performance in a numerical study.Boeing Strategic University Initiativ