A new suboptimal control design technique is proposed for a class of cascaded non-linear systems. The design is based on a forward recursive design rather than a backstepping design, and it utilizes a non-linear tracker derived using the state-dependent algebraic Riccati equation approach. The proposed design has two distinct features. First, it provides suboptimal performance with respect to a...

In this note suboptimal distributed and boundary control strategies for uid ows governed by the Navier-Stokes equation (NSE) together with aspects of the numerical and practical implementation of the underlying algorithms are presented. The objective of our numerical investigations is the development of practically relevant feedback control laws for ows over the backward facing step. For what f...

We address the inherent robustness properties of nonlinear systems controlled by suboptimal model predictive control (MPC), i.e., when a suboptimal solution of the (generally nonconvex) optimization problem, rather than an element of the optimal solution set, is used for the control. The suboptimal control law is then a set-valued map, and consequently, the closed-loop system is described by a ...

The problem of time optimal control design is considered for a chain of integrators. The suboptimal solution based on Implicit Lyapunov Function (ILF) method is presented in the form of continuous stabilizing feedback. The Semi-Definite Programming (SDP) problem with the constraints in the form of Linear Matrix Inequalities (LMI) is obtained for tuning the optimal parameters. The suboptimal sol...

This paper discusses a new iterative method for designing an H∞ low-order controller. The method is based on the optimization of a structurally constrained constant gain feedback controllers with linear matrix inequalities as the design constraints. In this new approach, the control gains are independent of any Riccati equation solutions. Controller constraints such as decentralization and posi...

The effectiveness of norm-based control methodologies heavily relies on the quality of the model that describes the dynamic behavior of the plant. In practical applications, the requirement to accurately describe the system at hand often results in high-order plant-models. On the other hand, low-order models are desired to end-up with low-order controllers that reduce implementational costs. Th...

A quadratic cheap control of linear systems with multiple state delays is considered. This optimal control problem is transformed to an optimal control problem of singularly perturbed systems. A composite suboptimal control of the latter is designed based on its asymptotic decomposition into two much simpler parameter-free subproblems, the slow and fast ones. Using this composite control, a sub...

Background Few Antiretroviral Therapy (ART) adherence trials investigate the reasons for intervention success or failure among HIV-positive individuals. Objectives To conduct qualitative research to explore the reasons for effectiveness of a 6-month mHealth (mobile health) trial that improved adherence among ART patients in China. The intervention utilized Wireless Pill Containers (WPCs) to p...

OBJECTIVE To evaluate the occurrence and nature of suboptimal intrapartum care in cases with metabolic acidosis in the newborn, and to estimate the degree to which this may be prevented. DESIGN Case-control study. Clinical audit. Setting Delivery units at two university hospitals in Sweden. POPULATION Out of 28 486 deliveries, 161 neonates > or =34 weeks of gestational age were born with me...

Background: Health promotion among health workers requires appropriate evidence of relevant determinants. Objective: This study was conducted to investigate the relationship between mental health and its measured covariates with self-rated health (SRH) among health workers during the COVID-19 pandemic in northwest Iran. Methods: In this cross-sectional study, we recruited 569 health workers f...