Search results for "75"

mplicit Identification of Contact Parameters in a Continuous Chain Model

2011

Accurate contact modeling is of great importance in the field of dynamic chain simulations. In this paper emphasis is on contact dynamics for a time-domain simulation model of large chains guided in a closed loop track. The chain model is based on theory for unconstrained rigid multibody dynamics where contact within the chain and with the track is defined through continuous point contacts using the contact indentation and rate as means. This paper presents an implicit method to determine contact parameters of the chain model through the use of none gradient optimization methods. The set of model parameters are estimated by minimizing the residual between simulated and measured results. The…

Discrete Learning Control with Application to Hydraulic Actuators

2015

In this paper the robustness of a class of learning control algorithms to state disturbances, output noise, and errors in initial conditions is studied. We present a simple learning algorithm and exhibit, via a concise proof, bounds on the asymptotic trajectory errors for the learned input and the corresponding state and output trajectories. Furthermore, these bounds are continuous functions of the bounds on the initial condition errors, state disturbance, and output noise, and the bounds are zero in the absence of these disturbances.

Computing Euclidean Steiner trees over segments

2020

In the classical Euclidean Steiner minimum tree (SMT) problem, we are given a set of points in the Euclidean plane and we are supposed to find the minimum length tree that connects all these points, allowing the addition of arbitrary additional points. We investigate the variant of the problem where the input is a set of line segments. We allow these segments to have length 0, i.e., they are points and hence we generalize the classical problem. Furthermore, they are allowed to intersect such that we can model polygonal input. As in the GeoSteiner approach of Juhl et al. (Math Program Comput 10(2):487–532, 2018) for the classical case, we use a two-phase approach where we construct a superse…

Pugnas por el control de la universidad después de la expulsión de los jesuitas

1990

Mi interés se centra en el análisis de los efectos del extrañamiento en los estudios universitarios y concretamente en Valencia. Resulta evidente que el decreto de extrañamiento produjo una efervescencia reformista en la Universidad. Es lógico porque, desde el momento en que empezó la campaña antijesuita, una de las razones alegadas fue la decadencia cultural que habían propiciado los padres de la Compañía a quienes se les atribuía el control de los instrumentos de poder. Así, los reformistas establecieron siempre una conexión entre la llegada al poder de los manteístas y la reforma de las letras. Desde esa perspectiva se comprende la expectación suscitada por el decreto de expulsión de los…

Experimental System Identification and Black Box Modeling of Hydraulic Directional Control Valve

2015

Directional control valves play a large role in most hydraulic systems. When modeling the hydraulic systems, it is important that both the steady state and dynamic characteristics of the valves are modeled correctly to reproduce the dynamic characteristics of the entire system. In this paper, a proportional valve (Brevini HPV 41) is investigated to identify its dynamic and steady state characteristics. The steady state characteristics are identified by experimental flow curves. The dynamics are determined through frequency response analysis and identified using several transfer functions. The paper also presents a simulation model of the valve describing both steady state and dynamic charac…

Analysis of Offshore Knuckle Boom Crane - Part Two: Motion Control

2013

In this paper design of electro-hydraulic motion control systems for offshore knuckle boom cranes is discussed. The influence of the control valve bandwidth along with the ramp time for the control signal are investigated both analytically with simplified system models and numerically with an experimentally verified crane model. The results of both types of investigations are related to general design rules for selection of control valves and ramp times and the relevance of these design rules is discussed. Generally, they are useful but may be too conservative for offshore knuckle boom cranes. However, as demonstrated in the paper, the only proper way to determine this is to evaluate the mo…

A Playful Experiential Learning System With Educational Robotics

2020

This article reports on two studies that aimed to evaluate the effective impact of educational robotics in learning concepts related to Physics and Geography. The reported studies involved two courses from an upper secondary school and two courses from a lower secondary school. Upper secondary school classes studied topics of motion physics, and lower secondary school classes explored issues related to geography. In each grade, there was an “experimental group” that carried out their study using robotics and cooperative learning and a “control group” that studied the same concepts without robots. Students in both classes were subjected to tests before and after the robotics laboratory, to c…

Gaig blau, Carraca (VER0000055)

Altres noms vulgars: European Roller (Anglès), Rollier d'Europe (Francès), Blauracke (Alemany) Gabinet de Vertebrats (Departament de Zoologia), Facultat de Ciències Biològiques (Campus de Burjassot), C/ Doctor Moliner, s/n, Bloque B. 5é plant, Burjassot (Valencia). Armari: 31-3 Adulto Adulto garrulus _

Pelicà, Pelícano común (VER0000063)

Altres noms vulgars: Great white pelican (Anglès), Pélican blanc (Francès), Rosapelikan (Alemany) Gabinet de Vertebrats (Departament de Zoologia), Facultat de Ciències Biològiques (Campus de Burjassot), C/ Doctor Moliner, s/n, Bloque B. 5é plant, Burjassot (Valencia). Armari: 5-2 Valencia Macho

_, Alcatraz atlántico (VER0000239)

Northern gannet (Anglès), _ (Francès), _ (Alemany) Gabinet de Vertebrats (Departament de Zoologia), Facultat de Ciències Biològiques (Campus de Burjassot), C/ Doctor Moliner, s/n, Bloque B. 5é plant, Burjassot (Valencia). Armari: 7-2