A Model Predictive Control Framework for Asymptotic Stabilization of Discretized Hybrid Dynamical Systems

We present a model predictive control (MPC) algorithm for the appropriate discretizations of (nondiscretized) hybrid dynamical systems. The optimization problem associated with the MPC algorithm is formulated with a set-based prediction horizon and the discretized hybrid dynamics as part of its constraints. Sufficient conditions guaranteeing structural properties of the problem and asymptotic stability of a closed set are revealed. These conditions include the existence of a control Lyapunov function assuring an invariance property on the terminal constraint set. In addition, we formulate a method to obtain numerical solutions to the hybrid optimal control problem, amenable to off-the-shelf optimization solvers, and demonstrate this method on the discretization of a prototypical hybrid system

Lessons for Remote Post-earthquake Reconnaissance from the 14 August 2021 Haiti Earthquake

On 14th August 2021, a magnitude 7.2 earthquake struck the Tiburon Peninsula in the Caribbean nation of Haiti, approximately 150 km west of the capital Port-au-Prince. Aftershocks up to moment magnitude 5.7 followed and over 1,000 landslides were triggered. These events led to over 2,000 fatalities, 15,000 injuries and more than 137,000 structural failures. The economic impact is of the order of US$1.6 billion. The on-going Covid pandemic and a complex political and security situation in Haiti meant that deploying earthquake engineers from the UK to assess structural damage and identify lessons for future building construction was impractical. Instead, the Earthquake Engineering Field Investigation Team (EEFIT) carried out a hybrid mission, modelled on the previous EEFIT Aegean Mission of 2020. The objectives were: to use open-source information, particularly remote sensing data such as InSAR and Optical/Multispectral imagery, to characterise the earthquake and associated hazards; to understand the observed strong ground motions and compare these to existing seismic codes; to undertake remote structural damage assessments, and to evaluate the applicability of the techniques used for future post-disaster assessments. Remote structural damage assessments were conducted in collaboration with the Structural Extreme Events Reconnaissance (StEER) team, who mobilised a group of local non-experts to rapidly record building damage. The EEFIT team undertook damage assessment for over 2,000 buildings comprising schools, hospitals, churches and housing to investigate the impact of the earthquake on building typologies in Haiti. This paper summarises the mission setup and findings, and discusses the benefits, and difficulties, encountered during this hybrid reconnaissance mission

Lessons for Remote Post-earthquake Reconnaissance from the 14 August 2021 Haiti Earthquake

On 14th August 2021, a magnitude 7.2 earthquake struck the Tiburon Peninsula in the Caribbean nation of Haiti, approximately 150 km west of the capital Port-au-Prince. Aftershocks up to moment magnitude 5.7 followed and over 1,000 landslides were triggered. These events led to over 2,000 fatalities, 15,000 injuries and more than 137,000 structural failures. The economic impact is of the order of US$1.6 billion. The on-going Covid pandemic and a complex political and security situation in Haiti meant that deploying earthquake engineers from the UK to assess structural damage and identify lessons for future building construction was impractical. Instead, the Earthquake Engineering Field Investigation Team (EEFIT) carried out a hybrid mission, modelled on the previous EEFIT Aegean Mission of 2020. The objectives were: to use open-source information, particularly remote sensing data such as InSAR and Optical/Multispectral imagery, to characterise the earthquake and associated hazards; to understand the observed strong ground motions and compare these to existing seismic codes; to undertake remote structural damage assessments, and to evaluate the applicability of the techniques used for future post-disaster assessments. Remote structural damage assessments were conducted in collaboration with the Structural Extreme Events Reconnaissance (StEER) team, who mobilised a group of local non-experts to rapidly record building damage. The EEFIT team undertook damage assessment for over 2,000 buildings comprising schools, hospitals, churches and housing to investigate the impact of the earthquake on building typologies in Haiti. This paper summarises the mission setup and findings, and discusses the benefits, and difficulties, encountered during this hybrid reconnaissance mission.</jats:p

A Model Predictive Control Framework for Hybrid Dynamical Systems⁎

This paper presents a model predictive control (MPC) algorithm that asymptotically stabilizes a compact set of interest for a given hybrid dynamical system. The considered class of systems are described by a general model, which identifies the dynamics by the combination of constrained differential and difference equations. The model allows for trajectories that exhibit multiple jumps at the same time instant, or portray Zeno behavior. At every optimization time, the proposed algorithm minimizes a cost functional weighting the state and the input during both the continuous and discrete phases, and at the terminal time via a terminal cost, without discretizing the continuous dynamics. To account for the structure of time domains defining solution pairs, the minimization is performed in a manner akin to free end-time optimal control. When the terminal cost is a control Lyapunov function on the terminal constraint set, recursive feasibility and asymptotic stability of the proposed algorithm can be guaranteed. A sample-and-hold control system and a bouncing ball model are two examples reported to demonstrate the applicability and effectiveness of the proposed approach

A Model Predictive Control Framework for Asymptotic Stabilization of Discretized Hybrid Dynamical Systems

We present a model predictive control (MPC) algorithm for the appropriate discretizations of (nondiscretized) hybrid dynamical systems. The optimization problem associated with the MPC algorithm is formulated with a set-based prediction horizon and the discretized hybrid dynamics as part of its constraints. Sufficient conditions guaranteeing structural properties of the problem and asymptotic stability of a closed set are revealed. These conditions include the existence of a control Lyapunov function assuring an invariance property on the terminal constraint set. In addition, we formulate a method to obtain numerical solutions to the hybrid optimal control problem, amenable to off-the-shelf optimization solvers, and demonstrate this method on the discretization of a prototypical hybrid system

Characterization of the Testis-Specific Angiotensin Converting Enzyme (tACE)-Interactome during Bovine Sperm Capacitation

A comprehensive understanding of molecular and biochemical changes during sperm capacitation is critical to the success of assisted reproductive technologies. We reported involvement of the testis-specific isoform of Angiotensin Converting Enzyme (tACE) in bovine sperm capacitation. The objective of this study was to characterize the tACE interactome in fresh and heparin-capacitated bovine sperm through immunoprecipitation coupled with mass spectrometry. These interactions were validated by co-localization of tACE with beta-tubulin as an identified interactome constituent. Although interactions between tACE and several proteins remained unchanged in fresh and capacitated sperm, mitochondrial aldehyde dehydrogenase 2 (ALDH2), inactive serine/threonine protein-kinase 3 (VRK3), tubulin-beta-4B chain (TUBB4B), and tubulin-alpha-8 chain (TUBA8) were recruited during capacitation, with implications for cytoskeletal and membrane reorganization, vesicle-mediated transport, GTP-binding, and redox regulation. A proposed tACE interactional network with identified interactome constituents was generated. Despite tACE function being integral to capacitation, the relevance of interactions with its binding partners during capacitation and subsequent events leading to fertilization remains to be elucidated