LGR-MPC: A user-friendly software based on Legendre-Gauss-Radau pseudo spectral method for solving Model Predictive Control problems

Active components, such as actuators, constitute a fundamental aspect of engineering systems, affording the freedom to shape system behavior as desired. However, this capability necessitates energy consumption, primarily in the form of electricity. Thus, a trade-off emerges between energy usage and desired outcomes. While open-loop optimal control methods strive for efficiency, practical implementation is hampered by disturbances and model discrepancies, underscoring the need for closed-loop controllers. The Proportional- Integral-Derivative (PID) controller is widely favored in industry due to its simplicity, despite sub-optimal responses in many cases. To bridge this gap, Model Predictive Control (MPC) offers a solution, yet its complexity limits its broad applicability. This paper introduces user-friendly Python-based MPC software, enabling easy access to MPC. The effectiveness of this software is demonstrated through multiple examples, including those with a known analytical solution.Comment: 19 pages, 16 figure

What’s in a Friendship? Partner Visibility Supports Cognitive Collaboration between Friends

Not all cognitive collaborations are equally effective. We tested whether friendship and communication influenced collaborative efficiency by randomly assigning participants to complete a cognitive task with a friend or non-friend, while visible to their partner or separated by a partition. Collaborative efficiency was indexed by comparing each pair’s performance to an optimal individual performance model of the same two people. The outcome was a strong interaction between friendship and partner visibility. Friends collaborated more efficiently than non-friends when visible to one another, but a partition that prevented pair members from seeing one another reduced the collaborative efficiency of friends and non-friends to a similar lower level. Secondary measures suggested that verbal communication differences, but not psychophysiological arousal, contributed to these effects. Analysis of covariance indicated that females contributed more than males to overall levels of collaboration, but that the interaction of friendship and visibility was independent of that effect. These findings highlight the critical role of partner visibility in the collaborative success of friends

Pressures to Comply or Defy: How Social Values Influence Perceptions of Healthcare Workers as Villains

During the Covid-19 pandemic, politicians, the media, and the public labeled frontline workers as heroes. The goal of this article is to examine how certain aspects of the Covid-19 pandemic—such as the nature of the Covid-19 virus, coupled with insufficient governmental and institutional responses—created a situation where it became possible for people to characterize healthcare workers as villains. This approach to medical professionals is rather novel in heroism studies and social sciences. A qualitative review of available data sources provided evidence that frontline healthcare workers were perceived negatively. Experiencing a lack of cooperation from patients and their families, healthcare personnel were forced to deal with institutional constraints that exacerbated these conflicts. Variables that could influence being villainized included the social value orientation and political persuasion of perceivers, as well as structural factors related to the transmission of effective and accurate information, including biased mass media presentations and genuine uncertainty from scientific sources

Leadership and Sexuality: Power, Principles and Processes

Although both leadership and sexuality are important and heavily researched topics, there is little work that addresses the interaction of the two areas. Leadership and Sexuality: Power, Principles, and Processes is a scholarly synthesis of leadership principles with issues related to sexuality and sexual policy-making. The authors\u27 multi-disciplinary analysis of the topic examines sexuality in the context of many different kinds of leadership, exploring both the good and the bad aspects of leadership and sexuality. These integrated topics are examined through three broad areas of study. The first involves individuals who become leaders in sexual domains by advancing new views of human sexuality. The second involves problems that leaders of businesses and other institutions must address as a result of issues related to human sexuality, including sexual harassment and sexually-based discrimination in the workplace. The third area involves understanding how being a leader influences sexual desire and sexual attraction, and may impact the course of workplace romance and the expression of sexuality.Written to be accessible to both laypeople and scholars, this book will appeal to academics and scientists interested in human sexuality as well as many related disciplines, including psychology, sociology, leadership studies, heroism science, political science, religion, and economics.https://scholarship.richmond.edu/bookshelf/1309/thumbnail.jp

The Dynamic Negotiated Exchange Model of Heroism and Heroic Leadership: Lessons From the COVID-19 Pandemic

This article proposes a new model of heroism and heroic leadership that conceptualizes the exchange relationship between heroic leaders and the recipients of heroic action as dynamic and negotiated. Previous exchange models portraying heroic leadership exchange as static and passive are shown to be inadequate under conditions of major societal upheaval. Underlying the Dynamic Negotiated Exchange (DNE) model is the idea that equitable hero–recipient exchange during times of societal crises becomes strained and subject to negotiated revision. The terms of the negotiation are first manifest in media dialogue and then translate to individual or structural reforms offering more equitable exchange outcomes. To illustrate our model, we use examples from the COVID-19 pandemic, during which dynamic negotiated exchanges are demonstrated in phenomena such as the Great Resignation and the Great Upgrade

Nested Control Co-design of a Spar Buoy Horizontal-axis Floating Offshore Wind Turbine

Floating offshore wind turbine (FOWT) systems involve several coupled physical analysis disciplines, including aeroelasticity, multi-body structural dynamics, hydrodynamics, and controls. Conventionally, physical structure (plant) and control design decisions are treated as two separate problems, and generally, control design is performed after the plant design is complete. However, this sequential design approach cannot fully capitalize upon the synergy between plant and control design decisions. These conventional design practices produce suboptimal designs, especially in cases with strong coupling between plant and control design decisions. Control co-design (CCD) is a holistic design approach that accounts fully for plant-control design coupling by optimizing these decisions simultaneously. CCD is especially advantageous for system design problems with complex interactions between physics disciplines, which is the case for FOWT systems. This paper presents and demonstrates a nested CCD approach using open-loop optimal control (OLOC) for a simplified reduced-order model that simulates FOWT dynamic behavior. This simplified model is helpful for optimization studies due to its computational efficiency, but is still sufficiently rich enough to capture important multidisciplinary physics couplings and plant-control design coupling associated with a horizontal-axis FOWT system with a spar buoy floating platform. The CCD result shows an improvement in the objective function, annual energy production (AEP), compared to the baseline design by more than eleven percent. Optimization studies at this fidelity level can provide system design engineers with insights into design directions that leverage design coupling to improve performance. These studies also provide a template for future more detailed turbine CCD optimization studies that utilize higher fidelity models and design representations.Comment: 21 pages, 15 figures, 5 table

Curb Your Heroism: How Larry David, an Old, Bald Misanthrope, Won the Hearts of Millions

For eleven television seasons, viewers of the series Curb Your Enthusiasm have been witness to a main character in Larry David who paradoxically displays attributes that are both endearing and revolting. This article offers an analysis of Larry David’s character with the goal of ascertaining his heroic nature, specifically focusing on whether he best meets the scientific criteria for a hero or for an antihero. Drawing from the literature of heroism science, we examine a large body of evidence from episodes of the series supporting arguments for both heroism and antiheroism in Larry’s character. Consistent with definitions of heroism, Larry manifests deviance, humility, loyalty to principles, and a growth mindset. Yet consistent with antiheroism, Larry shows selfishness, social insensitivity, manipulativeness, and resistance to growth. We conclude that any inconsistencies in his character can be understood through a consideration of Curb Your Enthusiasm’s comedic goals and sensibilities

SPOAC and Hinge Integrated MSAC: Non-holonomic Attitude Control Systems for Spacecraft

Two novel spacecraft attitude control system technologies are introduced that both rely on the same nonholonomic control trajectory concept but that utilize distinct system implementations. The first of these two technologies is Hinge Integrated Multifunctional Structures for Attitude Control (MSAC), which is a new attitude control system that utilizes deployable panels to provide a spacecraft with both fine pointing and large angle slewing attitude control capabilities. Given its potential for high reliability and these control capabilities, Hinge Integrated MSAC is a viable alternative to conventional momentum exchange-based attitude control systems. This study details the Technology Readiness Level (TRL) advancement for MSAC systems toward TRL 6 and introduces potential flight opportunities. We also introduce the Suspended Phased Oscillators for Attitude Control (SPOAC) system concept and mission design (which leverages MSAC control concepts), along with a prototype validation of the system. The Hinge Integrated MSAC system utilizes the deployable panel flexure/compliance to induce phased non-holonomic vibrations that generate largeangle slewing. Using flexure-based techniques, MSAC eliminates the need for sliding contact systems such as mechanical bearings, thereby eliminating a key failure mode of conventional reaction wheel assemblies (RWAs) and control moment gyroscopes (CMGs). The SPOAC operating concept is similar to that of MSAC, but instead of deployable panels, it employs levitating reaction masses that are oscillated using phased nonholonomic magnetic fields. The breakthrough SPOAC technology is ideal for small spacecraft and larger spacecraft that do not have large appendages, such as solar panels

Optimal Partitioning and Coordination Decisions in Decomposition-based Design Optimization.

Successful design of complex modern products is a grand challenge for design organizations. The task is becoming increasingly important due to economic competition and concern over safety, reliability, and energy efficiency. Automotive and aerospace products, for example, are composed of numerous interdependent subsystems with a level of complexity that surpasses the capability of a single design group. A common approach is to partition complex design problems into smaller, more manageable design tasks that can be solved by individual design groups. Effective management of interdependency between these subproblems is critical, and a successful design process ultimately must meet the needs of the overall system. Decomposition-based design optimization techniques provide a mathematical foundation and computational tools for developing such design processes. Two tasks must be performed so that decomposition-based design optimization can be used to solve a system design problem: partitioning the system into subproblems, and determining a coordination method for guiding subproblem solutions toward the optimal system design. System partition and coordination strategy have a profound impact on the design process. The effect of partitioning and coordination decisions have been studied independently, while interaction between these decisions has been largely ignored. It is shown here that these two sets of decisions do interact: how a system is partitioned influences appropriate coordination decisions, and vice versa. Consequently, addressing partitioning and coordination decisions simultaneously leads to improved system design processes. The combined partitioning and coordination decision problem is a difficult combinatorial problem. An evolutionary algorithm that solves this decision problem effectively is presented. The set of all partitioning and coordination options for a specific formulation framework, augmented Lagrangian coordination (ALC), is derived, and a method for choosing Pareto-optimal solutions from amongst these options is described. Concepts and techniques are demonstrated using several engineering example problems. A detailed model for an electric vehicle design problem is presented that considers three vehicle systems: powertrain, chassis, and structure, and partitioning and coordination decisions for this problem are analyzed.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/58449/1/jtalliso_1.pd

Impact of Strain-Actuated Attitude Control Systems for Variant Mission Classes

The University of Illinois, in collaboration with NASA Jet Propulsion Laboratory (JPL) and NASA Ames Research Center, has developed a novel Attitude Control System (ACS) called the Strain Actuated Solar Arrays (SASA), with sub-milli-arcsecond pointing capability. SASA uses strain-producing actuators to deform flexible deployable structures, and the resulting reaction forces rotate the satellite. This momentum transfer strategy is used for jitter reduction and small-angle slew maneuvers. The system is currently at a Technology Readiness Level of 4-5 and has an upcoming demonstration flight on the CAPSat CubeSat mission. An extension to the SASA concept, known as Multifunctional Structures for Attitude Control (MSAC), enables arbitrarily large-angle slew maneuvers in addition to jitter cancellation. MSAC can potentially replace reaction wheels and control moment gyroscopes for attitude control systems, thereby eliminating a key source of jitter noise. Both SASA and MSAC are more reliable because of fewer failure modes and lower failure rates as compared to conventional ACS, while having an overall smaller mass, volume, and power budget. The paper discusses the advantages of using SASA and MSAC for a wide range of spacecraft and variant mission classes.NSF Grant No. CMMI-1653118,NASA Contract No. NNX17CA25POpe