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International Solid-State Sensors, Actuators and Microsystems Conference

作者： Fang, Y.-J. Mukherjee, T. Fedder, G.K. Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA 15213 United States Robotics Institute Carnegie Mellon University Pittsburgh PA 15213 United States Institute for Complex Engineered Systems Carnegie Mellon University Pittsburgh PA 15213 United States

ISBN: (纸本)9781457701573

This paper presents a Si-CMOS-MEMS fabrication process that forms released structures out of a 10 m CMOS metal and oxide stack along with a 50 μm-thick section of the underlying silicon substrate. The process employs back-side silicon grinding that provides silicon mean roughness of 20 nm and maximum peak-to-valley roughness of 264 nm. The thinned MEMS substrate is bonded with solder preforms to a silicon base. Advanced Oxide Etch (AOE) of the CMOS MEMS stack has a rate of 527 nm/min and leaves no polymer residue. Three different thermal shunting methods during the silicon DRIE step are studied to alleviate isotropic silicon etch artifacts. Test of a Si-CMOS-MEMS crab-leg resonator validates the process. The device has a quality factor of 750 and resonant frequency of 36.4 kHz in air. © 2011 IEEE.

关键词： Natural frequencies

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The mapping of texture on VR polygonal models 2

The mapping of texture on VR polygonal models

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2nd International Conference on 3-D Digital Imaging and Modeling, 3DIM 1999

作者： Laurendeau, Denis Bertrand, Nathalie Houde, Régis Computer Vision and Systems Laboratory Department of Electrical Engineering and Computer Engineering Laval University QuebecQCG1K 7P4 Canada Robotics Division Hydro Quebec Research Institute VarennesQCJ3X 1S1 Canada

ISBN: (纸本)0769500625

The paper addresses the problem of choosing automatically, and without user intervention, the best possible 2D image that should be used to map as a texture on polygons of a geometric model of complex scenes made of several objects. The geometric models and the texture data are obtained separately: the models are built from range data while the texture information is obtained from 2D color images of the scene. The system does not make any assumption on the way the texture data has been acquired. Texture selection results are presented for an indoor scene. © 1999 IEEE.

关键词： Image texture

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Map building using fuzzy ART, and learning to navigate a mobile robot on an unknown world

Map building using fuzzy ART, and learning to navigate a mob...

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IEEE International Conference on robotics and Automation (ICRA)

作者： R. Araujo A.T. de Almeida Dept. of Electr. Eng. Coimbra Univ. Portugal Institute for Systems and Robotics (ISR) and Electrical Engineering Department University of Coimbra Portugal

This paper introduces a new approach, based on the application of the fuzzy ART neural architecture, for online map building from actual sensor data collected with a mobile robot. This method is then integrated as a complement, on the parti-game learning approach, allowing the system to make a more efficient use of collected sensor information. Also, a predictive online trajectory filtering method is introduced on the learning approach. Instead of having a mechanical device (robot) moving to search the world the idea is to have the system analysing trajectories in a predictive mode, by taking advantage of the improved world model. The real robot will only move to try trajectories that have been predicted to be successful, allowing lower exploration costs. This results on an overall new and powerful method for simultaneous and cooperative construction of a world model, and learning to navigate from an initial position to a goal region on an unknown world. It is assumed that the robot knows its own current world location. It is additionally assumed that the mobile robot is able to perform sensor-based obstacle detection (not avoidance), and straight-line motions. Results of experiments with a real Nomad 200 mobile robot will be presented, demonstrating the effectiveness of the proposed methods.

关键词： Subspace constraints Navigation Mobile robots Trajectory Robot sensing systems Buildings Mechanical sensors Sensor systems Filtering Predictive models

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Robot 3D force-based surface-tracking

Robot 3D force-based surface-tracking

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International Conference on Industrial Electronics, Control and Instrumentation

作者： R. Araujo U. Nunes A.T. de Almeida Dept. of Electr. Eng. Coimbra Univ. Portugal Institute of Systems and Robotics (ISR)Electrical Engineering Department University of Coimbra Coimbra Portugal

The problem of control of a robot manipulator performing compliant tasks is addressed. The force and position control is based on the Smith predictor design. For the overall control we are pursuing a behaviour-based architecture approach. The paper describes a 3D surface tracking behaviour controller. The tracking operation is performed in real-time using contact force feedback. Surface tracking is an important operation for self-teaching and exploratory tasks in unknown environments. It can be seen as a first step to the more general and important problem of surface following in contact. A method for tool tip contact frame calibration is presented. Results of simulations and real-time implementation are presented and discussed.< >

关键词： Force control Control systems Force feedback Force sensors Manipulator dynamics Robot control Position control Calibration Force measurement Geometry

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Nonlinear Model Predictive Control for Optimal Dose Administration in Radiotherapy 15th

Nonlinear Model Predictive Control for Optimal Dose Administ...

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15th Advanced Doctoral Conference on Computing, electrical and Industrial systems, DoCEIS 2024

作者： Araújo, João C. G. Guerreiro, Bruno J. Oliveira, Luis B. da Silva, Filipe Ferreira CTS-UNINOVA and LASI Department of Electrical and Computer Engineering NOVA School of Science and Technology Caparica2829-516 Portugal Institute for Systems and Robotics LARSyS Lisbon1049-001 Portugal CEFITEC Department of Physics NOVA School of Science and Technology Caparica2829-516 Portugal

ISBN: (纸本)9783031638503

This work discusses the nonlinear modeling of healthy and cancer cell population growth under the influence of radiotherapy, and proposes predictive control techniques to determine the optimal dose for tumor control, while sparing surrounding healthy tissue. Radiation effects are modelled by a linear-quadratic formalism, coupled with a novel population-specific delayed dose response. Numerical simulations of the open- and closed-loop system are conducted, and robustness against model uncertainty is studied. Results illustrate the controller’s performance when dealing with imperfect information and unexpected system behavior, and how it can be tuned to produce the desired treatment outcome. However, optimal operation is conditioned by a limited prediction horizon, as well as strict adherence to treatment schedules and dose restrictions. © IFIP International Federation for Information Processing 2024.

关键词： Nonlinear systems

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Harvesting Curvatures for Communication-Efficient Distributed Optimization

Harvesting Curvatures for Communication-Efficient Distribute...

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Asilomar Conference on Signals, systems & computers

作者： Diogo Cardoso Boyue Li Yuejie Chi João Xavier Department of Electrical and Computer Engineering Carnegie Mellon University USA Institute for Systems and Robotics IST-University of Lisbon Portugal

This paper considers the design of distributed optimization algorithms in the server-client setting, with the goal of achieving better communication efficiency, a crucial desiderata in modern distributed machine learning applications. One popular approach to reduce communication is to impose more computation between communication rounds, by letting each client optimize an approximation of the global objective function-constructed using the local objective function and aggregated history information-and exchange the updates with the parameter server for global consensus. In particular, judiciously incorporating second-order information in the local approximation often leads to better communication efficiency when the problem is ill-conditioned. However, existing methods construct the second-order correction term in an isotropic manner, without taking into account the curvature information of the global objective function accumulated over the course of the algorithm. This paper proposes a novel algorithm that refines this idea by constructing a second-order correction term using a BFGS-style update formula, where the kernel matrix is updated recursively using only history gradients to harvest curvature information for accelerating convergence. Numerical experiments demonstrate improved communication efficiency over competitive baseline algorithms on both synthetic and real datasets.

关键词： Machine learning algorithms Memory management Machine learning Approximation algorithms Linear programming Servers History

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Mobile Robot Path Learning on an Unknown Environment

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IFAC Proceedings Volumes 1997年第3期30卷 185-190页

作者： R. Araújo A.T. de Almeida Institute for Systems and Robotics (ISR) and Electrical Engineering Department University of Cosmbra Pólo II Pinhal de Marrocos 3030 Coimbra Portugal Telephone: +351 (39) 7006276/00 Fax: +351 (39) 35672

This paper deals with the problem of finding a mobile robot path on an unknown world environment. It is desired that the robot navigates to a known goal-region without colliding with physical obstracles. A learning approach will be presented for this purpose. It is supposed that the root has no initial map of Its environment. The robot uses its own infrared distance-sensors to detect obstacles present on its path. Simulation results will be presented that validate the effectiveness of the approach, where, besides detecting obstacles, the only other initial robot's ability is to perform straight-line motions.

关键词： Learning control path planning mobile robots

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Job shop scheduling problems with Genetic Algorithms

Job shop scheduling problems with Genetic Algorithms

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International Conference on computer engineering and systems

作者： Antonio Ferrolho Manuel Crisostomo Robert Wojcik Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Coimbra Portugal Department of Electrical Engineering Superior School of Technology of Viseu Polytechnic Institute of Viseu Viseu Portugal Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wroclaw Poland

ISBN: (纸本)1424413656;9781424413652

The Job-Shop Scheduling Problem (JSSP) is an extremely difficult problem because it requires very large combinational search space and the precedence constraint between machines. A software tool called Hybrid and Flexible Genetic Algorithm (HybFlexGA) was developed for solving the JSSP. Computational results demonstrate that the proposed HybFlexGA is very efficient and potentially useful in solving the JSSP. The results obtained with standard JSSP benchmark demonstrate its efficiency.

关键词： Job shop scheduling Genetic algorithms Artificial neural networks Space technology Simulated annealing Control engineering computing Genetic engineering Robot control Control systems Orbital robotics

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Synchronous Reluctance Motor Drive for Electric Vehicles Including Cross-Magnetic Saturation

Synchronous Reluctance Motor Drive for Electric Vehicles Inc...

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IEEE Conference on Vehicle Power and Propulsion (VPPC)

作者： A. P. Goncalves S. M. A. Cruz F. J. T. E. Ferreira A. M. S. Mendes Anibal T. De Almeida Institute of Systems and Robotics University of Coimbra Coimbra Portugal Department of Electrical and Computer Engineering University of Coimbra/IT Coimbra Portugal

This paper proposes a high-efficiency synchronous reluctance motor drive for the traction system of an electric vehicle. A vector control system, along with a maximum torque per ampere strategy was implemented taking into account the cross-magnetic saturation in the motor, to achieve a high- efficiency drive with a good dynamic behavior. Experimental results obtained in the laboratory, both in steady-state and transient regimes, demonstrate the feasibility and applicability of the developed control system for the target application.

关键词： Torque Induction motors Rotors Reluctance motors Stator windings

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Vision-based quadrotor stabilization using a pan and tilt camera

Vision-based quadrotor stabilization using a pan and tilt ca...

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2010 49th IEEE Conference on Decision and Control

作者： D. Cabecinhas C. Silvestre R. Cunha Department of Electrical Engineering and Computer Science and Institute for Systems and Robotics Instituto Superior Tecnico 1049-001 Lisboa Portugal

ISBN: (纸本)9781424477456

This paper proposes a nonlinear control architecture for the stabilization of a quadrotor vehicle based on image measurements of a set of landmarks obtained from a pan and tilt camera. The vehicle is stabilized vertically using an additional vertical position sensor and lateral-longitudinal stabilization is achieved with a nested saturation control law by feedback of image measurements, body attitude, and angular rate. Additionally, the pan and tilt camera is actively actuated to to keep the landmarks visible in the image sensor for most operating conditions. Simulation results are presented to assess the performance of the proposed control architecture.

关键词： Control Architecture Sensors (image) Cameras TILT landmarks position sensor

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