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The Output Regulation Problem for Unmodeled Reference/Disturbance Signals Using High-gain Observers
Jesús Alberto Meda-Campaña,Ricardo Ismael Ancona-Bravo,Jonathan Omega Escobedo-Alva,Tonatiuh Hernández-Cortés,Ricardo Tapia-Herrera 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.4
Based on the regulation theory and high-gain observers, in this paper, a controller for tracking and/or rejecting unmodeled but measurable signals is designed. Considering that the measurable reference/disturbance signals are bounded and smooth, it is proven that the missing dynamical models for such signals can be estimated by high-gain observers of dimensions equal to or greater than one. Then, the corresponding high-gain observers are embedded into an auxiliary system, known as the exosystem, allowing in this way, that the regulation theory can be applied and the new equations to be solved are also given. Because the exosystem is directly constructed from the high-gain observers, the proposed controller is robust in the sense that it is capable of tracking/rejecting any bounded and smooth signal as long as the estimations of the high-gain observers are sufficiently accurate. The existence conditions for such a controller are given, and numerical experiments are used to illustrate the efficacy of the proposed approach.
Hwarangs and Yueguang Tongzi: A New Analysis of the Relationship, With the Help of Textual Philology
Marco Campa 한국학중앙연구원 한국학중앙연구원 2023 THE REVIEW OF KOREAN STUDIES Vol.26 No.1
In this article I will address the question of religion the hwarang group professed and its relationship with Chinese heterodox sects. Particularly, those sects were built around the cult of Candraprabhākumāra, a minor character becoming the center of devotion not unlike that of Maitreya during the post-Han era, specifically during Sui-Tang dynasties. The major concerns of this paper are if Silla and hwarangs may have known about this heterodox figure, and if so, how and when. There will be a tentative of verification of Prof. Pankaj Mohan’s thesis in the light of other scholars, in particular Hubert Michael Seiwert, and most importantly Erich Zürcher, who tried first to study the Candraprabhākumāra’s cults. There will be an assessment of what we know about the hwarangs and what we know about Candraprabhākumāra that could be more related to them. More specifically, the Shouluo biqiu jing, a text examined by all there three scholars, will be analyzed in philological terms. On this basis and on the historical accounts known to us, new hypotheses will be formulated. The conclusions are that the Shouluo jing and the Candraprabhākumāra’s cults were known in Silla though the text was likely written in China as opposed to Pankaj Mohan’s hypothesis of its origin in the southern Korean kingdom. The hwarangs likely also knew that, by mediation of Baekje: the neighbor kingdom likely acted as a mediator for this particular form of Maitreya’s cult.
Kinematics and dynamics modeling of the 6-3-PUS-type Hexapod parallel mechanism
Jaqueline Bernal,Ricardo Campa,Israel Soto 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10
Modeling and analyzing the dynamics of mechanical systems is important for purposes of simulation, design and control. In the case of parallel manipulators, dynamics modeling becomes a complex task mainly due to the constraints imposed by the closed kinematic chains, and several methods have been proposed for solving that problem. Some authors suggest first using a non-minimal set of coordinates and then computing a minimal dynamics model by means of the so-called projection method. This paper reports the use of such procedure for obtaining the dynamics model of a particular parallel mechanism of the type known as 6-3-PUS. To compute the non-minimal dynamics we employed the Euler-Lagrange formulation. The computed kinematics and dynamics models were validated via numerical simulations. This modeling approach can be employed for similar mechanisms.
On Output Feedback Tracking Control of Robot Manipulators with Bounded Torque Input
Javier Moreno-Valenzuela,Victor Santibanez,Ricardo Campa 대한전기학회 2008 International Journal of Control, Automation, and Vol.6 No.1
Motivated by the fact that in many industrial robots the joint velocity is estimated from position measurements, the trajectory tracking of robot manipulators with output feedback is addressed in this paper. The fact that robot actuators have limited power is also taken into account. Let us notice that few solutions for the torque-bounded output feedback tracking control problem have been proposed. In this paper we contribute to this subject by presenting a theoretical reexamination of a known controller, by using the theory of singularly perturbed systems. Motivated by this analysis, a redesign of that controller is introduced. As another contribution, we present an experimental evaluation in a two degrees-of-freedom revolute-joint direct-drive robot, confirming the practical feasibility of the proposed approach.
Thromboprophylaxis in Abdominoplasty: Efficacy and Safety of a Complete Perioperative Protocol
Marangi, Giovanni Francesco,Segreto, Francesco,Poccia, Igor,Campa, Stefano,Tosi, Daniele,Lamberti, Daniela,Persichetti, Paolo Korean Society of Plastic and Reconstructive Surge 2016 Archives of Plastic Surgery Vol.43 No.4
Background Venous thromboembolism, a spectrum of diseases ranging from deep venous thrombosis to pulmonary embolism, is a major source of morbidity and mortality. The majority of cases described in plastic surgery involve abdominoplasty. Risk assessment and prophylaxis are paramount in such patients. General recommendations were recently developed, but the evidence in the literature was insufficient to prepare exhaustive guidelines regarding the medication, dosage, timing, or length of the prophylaxis. Methods A thromboprophylaxis protocol was developed for patients undergoing abdominoplasty. The protocol consisted of preoperative, intraoperative, and postoperative measures. Enoxaparin was administered as chemoprophylaxis in selected patients. The study involved 253 patients. The patients were analyzed for age, body mass index, enoxaparin dosage, risk factors, and complications. Results Deep venous thrombosis was documented in two cases (0.8%). No pulmonary embolism occurred. Three patients (1.2%) presented mild subcutaneous abdominal hematoma within the first postoperative week that spontaneously resorbed with neither aesthetic nor functional complications. Two patients (0.8%) presented severe hematoma requiring surgical re-intervention for drainage and hemostasis revision. Statistical analysis showed no significant correlation between enoxaparin dosage and hematoma (P=0.18) or deep venous thrombosis (P=0.61). Conclusions The described thromboprophylaxis protocol proved to be effective in the prevention of thrombotic events, with an acceptable risk of hemorrhagic complications. Furthermore, it provides new evidence regarding the currently debated variables of chemoprophylaxis, namely type, dosage, timing, and length.
Comesana-Gandara, B.,Hernandez, A.,de la Campa, J.G.,de Abajo, J.,Lozano, A.E.,Lee, Y.M. Elsevier Scientific Pub. Co 2015 Journal of membrane science Vol.493 No.-
Ortho-hydroxypolyimides (HPIs) undergo thermal rearrangement processes in a solid state at high temperatures to produce thermally rearranged polybenzoxazoles (TR-PBOs), which are promising materials for gas separation membranes due to their exceptional permeability-selectivity performance. The strong dependence between the structure of HPIs and the final properties of the TR-PBOs and the high cost of the HPI precursors are considered excellent reasons for their continued study. In this work, a set of low-cost HPIs were synthetized via the reaction of 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) with 2,4-diaminophenol dihydrochloride (DAP-Cl) and 4,6-diaminoresorcinol dihydrochloride (DAR-Cl). The polyimide made from 6FDA and m-phenylene diamine (MPD) was also obtained for comparison purposes. The polyimide precursors and the corresponding TR-PBOs, which were tested as films, were thoroughly characterized. The glass transition temperature of these precursor polyimides was shown to be a function of the number of hydroxyl groups such that the lowest value corresponded to the polyimide from MPD and the highest value corresponded to that derived from DAR. The conversion rate of HPIs to PBO at different processing temperatures was determined, and the highest conversion rate matched the DAP derived polyimide. With respect to their gas separation properties after thermal treatment at 450<SUP>o</SUP>C, these HPIs gave rise to TR-PBOs with very high permeability and satisfactory permselectivity values for several gas pairs.
Thromboprophylaxis in Abdominoplasty: Efficacy and Safety of a Complete Perioperative Protocol
Giovanni Francesco Marangi,Francesco Segreto,Igor Poccia,Stefano Campa,Daniele Tosi,Daniela Lamberti,Paolo Persichetti 대한성형외과학회 2016 Archives of Plastic Surgery Vol.43 No.4
Background Venous thromboembolism, a spectrum of diseases ranging from deep venous thrombosis to pulmonary embolism, is a major source of morbidity and mortality. The majority of cases described in plastic surgery involve abdominoplasty. Risk assessment and prophylaxis are paramount in such patients. General recommendations were recently developed, but the evidence in the literature was insufficient to prepare exhaustive guidelines regarding the medication, dosage, timing, or length of the prophylaxis. Methods A thromboprophylaxis protocol was developed for patients undergoing abdominoplasty. The protocol consisted of preoperative, intraoperative, and postoperative measures. Enoxaparin was administered as chemoprophylaxis in selected patients. The study involved 253 patients. The patients were analyzed for age, body mass index, enoxaparin dosage, risk factors, and complications. Results Deep venous thrombosis was documented in two cases (0.8%). No pulmonary embolism occurred. Three patients (1.2%) presented mild subcutaneous abdominal hematoma within the first postoperative week that spontaneously resorbed with neither aesthetic nor functional complications. Two patients (0.8%) presented severe hematoma requiring surgical re-intervention for drainage and hemostasis revision. Statistical analysis showed no significant correlation between enoxaparin dosage and hematoma (P=0.18) or deep venous thrombosis (P=0.61). Conclusions The described thromboprophylaxis protocol proved to be effective in the prevention of thrombotic events, with an acceptable risk of hemorrhagic complications. Furthermore, it provides new evidence regarding the currently debated variables of chemoprophylaxis, namely type, dosage, timing, and length.
A Practical PID Regulator with Bounded Torques for Robot Manipulators
Victor Santibanez,Karla Camarillo,Javier Moreno-Valenzuela,Ricardo Campa 제어·로봇·시스템학회 2010 International Journal of Control, Automation, and Vol.8 No.3
This paper proposes a saturated nonlinear PID regulator for industrial robot manipulators. Our control-ler considers the natural saturation problem given by the output of the control computer, the saturation phenomena of the internal PI velocity controller in the servo driver, and the actuator torque constraints of the robot manipulator. An approach based on the singular perturbations method is used to analyze the exponential stability of the closed-loop system. Experimental essays show the feasibility of the proposed controller. Furthermore, the theoretical results justify why the classical PID used in industrial robots preserves its exponential stability despite the saturation effects of the electronic control devices and the actuator torque constraints.