This article introduces an observer-based control strategy tailored for regulating plasma glucose in type 1 diabetes mellitus patients, addressing challenges like unknown time-varying delays and meal disturbances. This control strategy is based on an extended Bergman minimal model, a nonlinear glucose-insulin model to encompass unknown inputs, such as unplanned meals, exercise disturbances, or delays. The primary contribution lies in the design of an observer-based state feedback control in the presence of unknown long delays, which seeks to support and enhance the performance of the traditional artificial pancreas by considering realistic scenarios. The observer and control gains for the observer-based control are computed through linear matrix inequalities formulated from Lyapunov conditions that guarantee closed-loop stability. This design deploys a soft and gentle dynamic response, similar to a natural pancreas, despite meal disturbances and input delays. Numerical tests demonstrate the scheme's effectiveness in glycemic level regulation and hypoglycemic episode avoidance.
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http://dx.doi.org/10.1002/cnm.3826 | DOI Listing |
ISA Trans
December 2024
State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110169, China. Electronic address:
For Electro-Hydraulic Actuators (EHA) with parametric uncertainties and mismatched and matched disturbances, most existing robust adaptive control strategies can achieve only uniformly ultimately bounded tracking errors. An Extended-State-Observer (ESO) based asymptotic control scheme is proposed by incorporating the prescribed performance control into the backstepping framework to ensure satisfied tracking performance and anti-disturbance ability of EHA systems. A novel ESO is designed to acquire an asymptotic estimation without prior bounds of the mismatched disturbance and its derivatives.
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December 2024
National Key Laboratory of Aerospace Flight Dynamics, School of Astronautics, Northwestern Polytechnical University, Xi'an 710072, China; Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, China. Electronic address:
This paper investigates an integrated model-control scheme for large-scale spacecraft, focusing on orbit-attitude-vibration dynamics subject to strong time-varying coupling characteristics. The proposed scheme aims to achieve cooperative modeling and control for orbit maintenance, attitude stabilization and vibration suppression simultaneously. An integrated dynamic model is established using the Absolute Nodal Coordinate Formulation and Lagrangian mechanics, where time-varying coupling terms are preserved to enhance model integrity, contrasting with the reduction and decoupling methods commonly adopted in existing literature.
View Article and Find Full Text PDFInt J Environ Res Public Health
December 2024
Design Studies Department, University of Wisconsin-Madison, Madison, WI 53706, USA.
An increasing body of literature has investigated the implications of housing quality on health, confirming the negative consequences of poor housing quality on physical and mental health. Despite this increased focus on the salutogenic impacts of housing, the relationship between housing quality and cognitive health remains understudied. This study examined how the housing quality in urban informal settlements, where living conditions are often substandard, affects women's cognitive functioning, with a specific focus on executive function (EF) skills.
View Article and Find Full Text PDFInt J Med Robot
February 2025
Faculty of Health, Education, Medicine and Social Care, Medical Technology Research Centre, The Institute of Excellence in Robotic Surgery, Anglia Ruskin University, Chelmsford, UK.
Background: The human eye consists of highly sensitive, hydrated, and relatively thin tissues, making precise control and accurate force estimation crucial in robotic eye surgery. This paper introduces a novel control method and state observer designed for a gripper surgical instrument used on the external ocular surface during robotic eye surgery.
Methods: A novel state observer, operating in tandem with the controller, estimates the applied force.
ISA Trans
December 2024
Department of Automation, Key Laboratory of System Control and Information Processing of Ministry of Education, Key Laboratory of Marine Intelligent Equipment and System of Ministry of Education, Shanghai Engineering Research Center of Intelligent Control and Management, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address:
This paper presents the design of a disturbance rejection-based control strategy for a quadrotor unmanned aerial vehicle subject to model uncertainties and external disturbances described by turbulent wind gusts of severe intensity. First, an extended state observer is introduced to supply full-state and total disturbance estimations within a fixed time regardless of initial estimation errors. Then, an adaptive non-singular fast terminal sliding mode controller with a single-gain structure is proposed to reduce the tuning complexity and drive the pose of the rotorcraft while providing practical finite-time convergence, robustness to bounded external disturbances, non-overestimation of its control gain, and chattering attenuation.
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