In this paper, we addressed the problem of controlling the position of a group of unicycle-type robots to follow in formation a time-varying reference avoiding obstacles when needed. We propose a kinematic control scheme that, unlike existing methods, is able to simultaneously solve the both tasks involved in the problem, effectively combining control laws devoted to achieve formation tracking and obstacle avoidance. The main contributions of the paper are twofold: first, the advantages of the proposed approach are not all integrated in existing schemes, ours is fully distributed since the formulation is based on consensus including the leader as part of the formation, scalable for a large number of robots, generic to define a desired formation, and it does not require a global coordinate system or a map of the environment. Second, to the authors’ knowledge, it is the first time that a distributed formation tracking control is combined with obstacle avoidance to solve both tasks simultaneously using a hierarchical scheme, thus guaranteeing continuous robots velocities in spite of activation/deactivation of the obstacle avoidance task, and stability is proven even in the transition of tasks. The effectiveness of the approach is shown through simulations and experiments with real robots.
This investigation builds on the Alvarez et al. (2021) Project Completion Report (PCR) analysis and its aim is to assess the implications of that study for the current portfolio of projects under execution at the Inter-American Development Bank (IDB). We use the sample of PCRs which reached operational closure (CO) in 2017 and 2018 to estimate the impact that design and execution performance characteristics of projects played in the likelihood of ending as successful and/or effective. Based on the estimated coefficients, we construct risk curves to isolate the effect specific characteristics have on the likelihood of a project being classified as unsuccessful/ineffective. We then use the estimated coefficients and, using the actual values for the current portfolio of projects in execution, identify the fraction of the portfolio that is at risk of ending as unsuccessful/ineffective projects. According to our analysis, of the 249 projects assessed, 39 have a 50% or less chance of being successful. Thirteen (13) projects have less than a 10% chance. For about 70% of the projects analyzed, given the characteristics they exhibit, the likelihood that they end up successful has already been curtailed. The type of analysis presented here can help IDB Management identify key performance indicators to keep track of during execution to periodically assess the level of risk it is willing to accept in terms of projects ending unsuccessful/ineffective as rated by the current PCR methodology.
The goal of development assistance is to deliver measurable results. At the Inter-American Development Bank (IDB), the Development Effectiveness Framework (DEF) was adopted to enhance the likelihood this goal is met. The key objective of this analysis is to enhance our understanding of the role the set of tools and processes adopted at the IDB, from project design to completion, play in the assessment of a projects success and effectiveness. Specifically, we are interested in teasing out the role different dimensions of project design, assessed through the Development Effectiveness Matrix (DEM), and execution performance indicators, as per the Project Monitoring Report (PMR), have on the delivery of effective and successful projects measured through the Project Completion Report (PCR) methodology implemented at the IDB. We also explore the validation process of PCRs and delve into the effectiveness analysis at the level of specific objectives and result indicators, identifying key pitfalls associated with objectives not being met. Overall, our findings provide strong validation for the DEF and its tools. We find robust evidence for the importance of the quality at entry assessment conducted through the DEM. In particular, the quality of the results matrix at approval is a strong determinant of project success and effectiveness at closure, and the quality of the Evaluation Plan is strongly associated with the effectiveness of a project. In terms of execution performance, our analysis finds that, on average, projects that execute a lower share of their approved loan amount, are put on Alert, or are classified as a Problem, in its first three years of execution; and projects that experience a higher share of their outputs discontinued, with respect to their first results matrix, are most likely to be ineffective in achieving their objectives and will likely be rated as unsuccessful.
Las Facultades de Ciencias e Ingeniería y el Departamento de Diseño industrial de la Facultad de Artes, de la Universidad Nacional de Colombia sede de Bogotá, ofrecen el programa de formación profesional de Ingeniería Mecatrónica con el propósito de fundamentar la innovación y el desarrollo de productos y procesos inteligentes en Colombia. La naturaleza de la mecatrónica es en esencia conocimiento y tecnología de carácter transdisciplinario que cubre los límites de la frontera común entre la mecánica, la microelectrónica, la computación (informática) y el control automatizado. Así, la mecatrónica agrupa un conjunto de diversas áreas de la tecnología relacionadas con los sensores y los sistemas de medición, los sistemas de impulsión (o transmisión) y operación, el análisis del comportamiento de sistemas mecánicos, los sistemas de control y los sistemas de microprocesadores y el correspondiente soporte de software. La creación de la carrera y la apertura del programa fueron autorizadas por el Consejo Académico de la Universidad Nacional de Colombia mediante los Acuerdos N° 014 y 015, respectivamente, del 22 de agosto de 2001.
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