News & Events

77 were found.


  •  NEWS   MERL researchers present 10 papers at the American Controls Conference
    Date: July 3, 2015
    MERL Contacts: Daniel Nikovski; Yebin Wang; Uros Kalabic; Stefano Di Cairano; Arvind Raghunathan; Avishai Weiss; Daniel Burns
    Research Areas: Mechatronics, Data Analytics
    Brief
    • MERL researchers presented 10 papers at the American Controls Conference, in Chicago, USA. The ACC is one of the most important conferences on control systems in the world. Topics ranged from theoretical, including new algorithms for Model Predictive Control and Co-Design, to applications including spacecraft control and HVAC systems.
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  •  NEWS   MERL and Mitsubishi Electric researchers presented at the SIAM Conference on Control and Its Applications 2015
    Date: July 13, 2015
    Where: SIAM Conference on Control and Its Applications 2015
    MERL Contact: Andrew Knyazev
    Research Areas: Algorithms, Mechatronics, Advanced Control Systems, Computational Sensing, Multimedia
    Brief
    • MERL and Mitsubishi Electric researchers presented talks at the SIAM Conference on Control and Its Applications 2015. The papers were published by SIAM in the conference proceedings.
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  •  NEWS   MERL's High-speed optimization algorithms showcased at Mitsubishi Electric Corporation annual R&D Open House
    Date: February 13, 2014
    MERL Contact: Matthew Brand
    Research Areas: Algorithms, Mechatronics, Computer Vision
    Brief
    • Mitsubishi Electric Corporation announced its development of advanced optimization algorithms and high-speed calculation methods aimed at optimizing the performance of three practical systems: laser-processing machines for high-speed cutting of sheet metal using the shortest possible trajectories, moon probes achieved with minimized fuel consumption, and particle beam therapies for prompt medical treatments.
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  •  TALK   The Wireless Control Network: A New Approach For Control Over Networks
    Date & Time: Friday, October 18, 2013; 12:00 PM
    Speaker: Dr. Shreyas Sundaram, University of Waterloo
    MERL Host: Mouhacine Benosman
    Research Area: Mechatronics
    Brief
    • This talk will describe a method to stabilize a plant with a network of resource-constrained wireless nodes. As opposed to traditional networked control schemes where the nodes simply route information to and from a dedicated controller, our approach treats the network itself as the controller. Specifically, we formulate a strategy where each node repeatedly updates its state to be a linear combination of the states of neighboring nodes. We show that this causes the entire network to behave as a linear dynamical system, with sparsity constraints imposed by the network topology. We provide a numerical design procedure to determine the appropriate linear combinations for each node so that the transmissions of the nodes closest to the actuators are stabilizing. We also make connections to decentralized control theory and the concept of fixed modes to provide topological conditions under which stabilization is possible. We show that this "Wireless Control Network" requires low computational and communication overhead, simplifies transmission scheduling, and enables compositional design. We also consider the issue of security in this control scheme. Using structured system theory, we show that a certain number of malicious or misbehaving nodes can be detected and identified provided that the connectivity of the network is sufficiently high.
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  •  TALK   Design of Active Inputs for Set-Based Fault Diagnosis
    Date & Time: Friday, September 6, 2013; 12:00 PM
    Speaker: Dr. Davide M. Raimondo, University of Pavia, Italy
    MERL Host: Stefano Di Cairano
    Research Area: Mechatronics
    Brief
    • Although there are many fault diagnosis algorithms available, there has been very little work on the design or modification of control inputs with the aim of increasing the detectability and isolability of faults. The use of such inputs has clear potential for overcoming a central difficulty in fault detection, which is to distinguish the effects of faults from those of disturbances, process uncertainties, etc. Accordingly, the use of active inputs could be a transformative technology in industry, provided that such inputs can be computed reliably and efficiently.
      This presentation discusses new methods for computing active inputs that guarantee that the input-output data of a process will be sufficient to correctly identify a fault from a given library of possible faults. This problem is inherently nonconvex and has a combinatorial dependence on the number of faults considered. To address this, a new formulation is considered, along with related approximations, that is amenable to efficient solution using standard optimization packages (e.g. CPLEX). The theoretical contributions combine ideas from reachability analysis, set-based computations, and optimization theory to exploit detailed problem structure and thereby manage the problem complexity. Comparisons with an existing method show that the proposed formulation provides a dramatic reduction in the required computational effort.
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  •  TALK   Decoupling Systems By Design
    Date & Time: Friday, August 23, 2013; 12:00 PM
    Speaker: Dr Cornel Sultan, Virginia Tech
    Research Area: Mechatronics
    Brief
    • Coordinate coupling raises serious numerical, analysis, and control design problems that grow with the size of the system. On the other hand, decoupled dynamic equations facilitate all of the above processes since each equation can be treated independently. Unfortunately, due to the inherent heterogeneity typical of most practical, complex systems, these are not naturally decoupled so developing accurate enough decoupled approximations is of interest.

      In this talk the issue of building such accurate decoupled approximations is addressed by leveraging concepts from robust control theory. Specifically, system gains (e.g. energy gain, peak to peak gain) are used to characterize the approximation error. Then some system parameters are selected to minimize this approximation error. The advantage of using system gains is that the decoupling approximation is guaranteed to be accurate over an entire class of signals (e.g. finite energy/finite peak signals). These ideas are illustrated on linearized models of tensegrity structures which are designed to yield accurate decoupled models with respect to all signals of finite energy and finite peak. Further analysis corrects several misconceptions regarding decoupling, system properties, and control design.
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  •  TALK   Topics in Intelligent Building Systems Control
    Date & Time: Tuesday, July 23, 2013; 12:00 PM
    Speaker: Dr. Sandipan Mishra, Renssealer Polytechnic Institute
    MERL Host: Stefano Di Cairano
    Research Area: Mechatronics
    Brief
    • This talk will present the breadth of research activities in the Intelligent Systems, Automation & Control Laboratory at Rensselaer Polytechnic Institute, ranging from building systems control to additive manufacturing and adaptive optics. In particular, we will focus on the modeling and control design paradigms for intelligent building systems and smart LED lighting systems. Since building systems have substantial variability of occupancy, usage, ambient environment, and physical properties over time, strategies for "model-free" control algorithms for building temperature control will be illustrated. The seminar will also discuss the state-of-the-art in feedback control of lighting systems and demonstrate the efficacy of distributed control and consensus type algorithms for these large-scale lighting systems. Finally, some interesting examples of bio-inspired estimation from blurry images for adaptive optics will be presented.
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  •  TALK   Challenges in Model-Based System Engineering: Past, Present and Future
    Date & Time: Tuesday, July 16, 2013; 12:00 PM
    Speaker: Dr. Michael Tiller, Xogeny
    MERL Host: Daniel Burns
    Research Area: Mechatronics
    Brief
    • Model-based System Engineering has been recognized, for some time, as a way for companies to improve their product development processes. However, change takes time in engineering and we still have only scratched the surface of what is possible. New ideas and technologies are constantly emerging that can improve a model-based approach. In this talk, I will discuss some of my past experiences with model-based system engineering in the automotive industry. I'll also discuss the shifts I see from numerical approaches to more symbolic approaches and how this manifests itself in a shift from imperative representations of engineering models to more declarative ones. I'll cover some of the interesting challenges I've seen trying to model automotive systems and how I think those challenges can be overcome moving forward. Finally, I'll talk about some of the exciting possibilities I see on the horizon for modeling.
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  •  NEWS   International Journal of Control: publication by Matthew E. Brand, Scott A. Bortoff and Stefano Di Cairano
    Date: July 9, 2013
    Where: International Journal of Control
    MERL Contacts: Stefano Di Cairano; Matthew Brand; Scott Bortoff
    Research Areas: Algorithms, Mechatronics, Advanced Control Systems
    Brief
    • The article "Projection-free Parallel Quadratic Programming for Linear Model predictive Control" by Di Cairano, S., Brand, M. and Bortoff, S.A. was published in International Journal of Control
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  •  TALK   On distributed conflict resolution at road intersections
    Date & Time: Wednesday, June 26, 2013; 12:00 PM
    Speaker: Gabriel Rodrigues de Campos, Chalmers University
    MERL Host: Mouhacine Benosman
    Research Area: Mechatronics
    Brief
    • In this talk, we consider a scenario where several vehicles have to coordinate among them in order to cross a traffic intersection. Thus, the control problem relies on the optimization of global cost function while guaranteeing collision avoidance and the satisfaction of local constraints. We propose a decentralized solution, where vehicles sequentially solve local optimization problems allowing them to cross, in a safe way, the intersection. Such approach pays a special attention to how quantify the degrees of freedom that each vehicle disposes to avoid a potential collision and lead to an adequate formalism in which collision avoidance is enforced through local state constraints at given time instants. Finally, simulations results on the efficiency, performance and optimality of the proposed approach are presented at the end of the talk.
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  •  NEWS   ACC 2013: 7 publications by Yebin Wang, Arvind U. Raghunathan, Scott A. Bortoff, Yiming Zhao, Zafer Sahinoglu and Stefano Di Cairano
    Date: June 17, 2013
    Where: American Control Conference (ACC)
    MERL Contacts: Scott Bortoff; Stefano Di Cairano; Yebin Wang; Arvind Raghunathan
    Research Areas: Mechatronics, Electronics & Communications, Data Analytics
    Brief
    • The papers "Sub-optimal Control Design of a Semi-active Vibration Reduction System" by Wang, Y. and Utsunomiya, K., "Adaptive Estimation of State of Charge for Lithium-ion Batteries" by Fang, H., Wang, Y., Sahinoglu, Z., Wanda, T. and Hara, S., "Vehicle Yaw Dynamics Control by Torque-based Assist Systems Enforcing Driver's Steering Feel Constraints" by Zafeiropoulos, S. and Di Cairano, S., "Speed Profile Optimization for Optimal Path Tracking" by Zhao, Y. and Tsiotras, P., "Real-Time Energy-Optimal Trajeactory Generatin for a Servo Motor" by Zhao, Y., Wang, Y., Bortoff, S.A. and Ueda, K., "Global Optimization of Multi-period Optimal Power Flow" by Gopalakrishnan, A., Raghunathan, A.U., Nikovski, D., Biegler, L.T. and "Semismooth Equation Approach to Network Utility Maximization (NUM)" by Bai, L. and Raghunathan, A.U. were presented at the American Control Conference (ACC)
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  •  NEWS   CLIMA 2013: publication by Daniel N. Nikovski and others
    Date: June 16, 2013
    Where: REHVA World Congress (CLIMA)
    MERL Contact: Daniel Nikovski
    Research Areas: Data Analytics, Advanced Control Systems
    Brief
    • The paper "A Method for Computing Optimal Set-Point Schedule for HVAC Systems" by Nikovski, D., Xu, J. and Nonaka, M. was presented at the REHVA World Congress (CLIMA)
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  •  NEWS   IEEE Transactions on Control Systems Technology: publication by Stefano Di Cairano and others
    Date: June 14, 2013
    Where: IEEE Transactions on Control Systems Technology
    MERL Contact: Stefano Di Cairano
    Research Area: Mechatronics
    Brief
    • The article "Vehicle Yaw Stability Control by Coordinated Active Front Steering and Differential Braking in the Tire Sideslip Angles Domain" by Di Cairano, S., Tseng, H.E., Bernardini, D. and Bemporad, A. was published in IEEE Transactions on Control Systems Technology
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  •  NEWS   CIRP CMMO 2013: publication by Alan Sullivan and others
    Date: June 13, 2013
    Where: CIRP Conference on Modeling of Machining Operations (CIRP CMMO)
    MERL Contact: Alan Sullivan
    Research Areas: Mechatronics, Computational Geometry
    Brief
    • The paper "Cutter Workpiece Engagement Calculations for Five-axis Milling using Composite Adaptively Sampled Distance Fields" by Erdim, H. and Sullivan, A. was presented at the CIRP Conference on Modeling of Machining Operations (CIRP CMMO)
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  •  NEWS   Hybrid Systems: Computation and Control (HSCC) 2013: publication by Stefano Di Cairano and others
    Date: April 8, 2013
    Where: Hybrid Systems: Computation and Control (HSCC)
    MERL Contact: Stefano Di Cairano
    Research Areas: Mechatronics, Advanced Control Systems
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  •  NEWS   SIAM Journal of Scientific Computing: publication by Andrew Knyazev and others
    Date: March 14, 2013
    Where: SIAM Journal of Scientific Computing
    MERL Contact: Andrew Knyazev
    Research Area: Algorithms
    Brief
    • The article "Absolute Value Preconditioning for Symmetric Indefinite Linear Systems" by Vecharynski, E. and Knyazev, A.V. was published in SIAM Journal of Scientific Computing
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  •  NEWS   Mitsubishi Electric Develops Ultra-High Resolution 3D Shape Representation Technology
    Date: February 12, 2013
    MERL Contact: Alan Sullivan
    Research Area: Mechatronics
    Brief
    • Mitsubishi Electric Corporation (TOKYO: 6503) announced today it has developed ultra-high resolution 3D shape representation technology for numerically controlled (NC) machine tools. The technology displays detailed shapes of machined surfaces down to a resolution of 1 micrometer (um) in a 3D machining simulation, which machine operators can use to evaluate surface textures without trial cutting through a high quality machining process.
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  •  NEWS   Journal of Computational and Nonlinear Dynamics: publication by Tamas Kalmar-Nagy and others
    Date: January 25, 2013
    Where: Journal of Computational and Nonlinear Dynamics
    Research Areas: Mechatronics, Dynamical Systems
    Brief
    • The article "Characterization of Flow-Magnetic Field Interactions in Magneto-Hydrodynamic Turbulence" by Richard, J.C., Kumar, G., Kalmar-Nagy, T. and Girimaji, S.S. was published in Journal of Computational and Nonlinear Dynamics
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  •  NEWS   International Journal of Robust and Nonlinear Control: publication by Stefano Di Cairano and others
    Date: January 24, 2013
    Where: International Journal of Robust and Nonlinear Control
    MERL Contact: Stefano Di Cairano
    Research Area: Mechatronics
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  •  TALK   Estimation of time-varying parameters in nonlinear systems: Application to building systems and Extremum seeking control
    Date & Time: Tuesday, December 18, 2012; 12:00 PM
    Speaker: Prof. Martin Guay, Queen's University
    MERL Host: Daniel Burns
    Research Area: Mechatronics
    Brief
    • In this presentation, an adaptive estimation technique for the estimation of time-varying parameters for a class of continuous-time nonlinear system is proposed. In the first part of the talk, we present an application of the estimation routine for the estimation of unknown heat loads and heat sinks in building systems. The technique proposed is a set-based adaptive estimation that can be used to estimate the time-varying parameters along with an uncertainty set. The proposed method is such that the uncertainty set update is guaranteed to contain the true value of the parameters. Unlike existing techniques that rely on the use of polynomial approximations of the time-varying behaviour of the parameters, the proposed technique does not require a functional representation of the time-varying behaviour of the parameter estimates.

      In the second part of the talk, we consider the application of the estimation technique for the solution of a class of real-time optimization problems. It is assumed that the equations describing the dynamics of the nonlinear system and the cost function to be minimized are unknown and that the objective function is measured. The main contribution is to formulate the extremum-seeking problem as a time-varying estimation problem. The proposed approach is shown to avoid the need for averaging results which minimizes the impact of the choice of dither signal on the performance of the extremum seeking control system.
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