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  • 1.
    Alepuz, Javier Pérez
    et al.
    University of Alicante.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Pomares, Jorge
    University of Alicante.
    Direct image-based visual servoing of free-floating space manipulators2016In: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 55, 1-9 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents an image-based controller to perform the guidance of a free-floating robot manipulator. The manipulator has an eye-in-hand camera system, and is attached to a base satellite. The base is completely free and floating in space with no attitude control, and thus, freely reacting to the movements of the robot manipulator attached to it. The proposed image-based approach uses the system's kinematics and dynamics model, not only to achieve a desired location with respect to an observed object in space, but also to follow a desired trajectory with respect to the object. To do this, the paper presents an optimal control approach to guiding the free-floating satellite-mounted robot, using visual information and considering the optimization of the motor commands with respect to a specified metric along with chaos compensation. The proposed controller is applied to the visual control of a four-degree-of-freedom robot manipulator in different scenarios.

  • 2.
    Bazzocchi, Michael C. F.
    et al.
    University of Toronto, Institute for Aerospace Studies.
    de Decker, Nathan
    University of Liège.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Application of pseudo-equinoctial shaping to Near-Earth asteroid orbital transfer2017In: IEEE Aerospace Conference Proceedings, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, 7943777Conference paper (Refereed)
    Abstract [en]

    This paper determines the near-optimal transfer trajectory of a Near-Earth Asteroid (NEA) to an orbit in the Earth-Moon system through the use of an ion beam redirection method. The ion beam method is a hovering approach to asteroid redirection. The method operates through the use of two diametrically opposed thrusters. The redirection mission targets Arjuna-type asteroids, and uses a sample asteroid, 2013 RZ53, to demonstrate the applicability of the pseudo-equinoctial shaping to asteroid orbital transfer. The asteroid transfer from its initial orbit about the Sun to its final orbit in the Earth-Moon system is divided into two phases using a patched conics approximation. The first phase includes the transfer of the asteroid from its initial orbit to an optimized rendezvous point with Earth. The second phase begins as soon as the asteroid arrives within the Earth's sphere of influence and ends with the transfer of the asteroid into a stable orbit about Earth and Moon. The pseudo-equinoctial shaping approach is employed during each phase, and determines the near-optimal solution for the lowest combined delta-v required to complete the orbital transfer. The pseudo-equinoctial method is a shape-based approach to trajectory design which assumes the trajectory transfer can be modelled as a variation of a conic arc. The transfer considers the eccentricity, inclination, and semi-major axis, as well as optimizes several free parameters, such as the thrust, the start of transfer and the rendezvous point with Earth. The optimization is completed using a genetic algorithm, and the results of the optimization are presented in terms of time of flight, thrust, number of revolutions, and delta-v. Lastly, the results are detailed and the feasibility of a redirection mission for an Arjuna-type asteroid is discussed.

  • 3.
    Bazzocchi, Michael C.F.
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Application of asteroid redirection methods to orbital debris removal2016In: 2016 IEEE Aerospace Conference: AERO 2016, Big Sky, United States, 5 - 12 March 2016, Piscataway, NJ: IEEE Communications Society, 2016, 7500750Conference paper (Refereed)
    Abstract [en]

    This paper discusses the applicability of some of the asteroid redirection methods, prominently studied in the literature, to orbital debris removal. The tasks of asteroid redirection and orbital debris removal share the common goal of controlled redirection of an uncooperative target. Three asteroid redirection methods are systematically compared and analyzed to assess their viability for an orbital debris reentry mission, i.e., ion beam shepherd, laser sublimation, and tugboat. These methods are investigated in terms of the characteristics of the orbital debris population and based on the major criteria for mission design of controlled reentry of uncooperative objects. In addition, the uncertainty intrinsic to the orbital debris population is quantified through the use of a Monte Carlo simulation, which provides insight into the robustness of the methods for various ranges of orbital debris. The Analytical Hierarchy Process will be employed to assess the viability of each method in a logically consistent fashion, namely, through aggregation of the relative preference (of each method) and relative importance (of each criterion). The advantages and drawbacks of each redirection method are discussed in light of the assessment results for orbital debris reentry

  • 4.
    Bazzocchi, Michael C.F.
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Comparative analysis of redirection methods for asteroid resource exploitation2016In: Acta Astronautica, ISSN 0094-5765, E-ISSN 1879-2030, Vol. 120, 1-19 p.Article in journal (Refereed)
    Abstract [en]

    An in-depth analysis and systematic comparison of asteroid redirection methods is performed within a resource exploitation framework using different assessment mechanisms. Through this framework, mission objectives and constraints are specified for the redirection of an asteroid from a near-Earth orbit to a stable orbit in the Earth-Moon system. The paper provides a detailed investigation of five redirection methods, i.e., ion beam, tugboat, gravity tractor, laser sublimation, and mass ejector, with respect to their capabilities for a redirection mission. A set of mission level criteria are utilized to assess the performance of each redirection method, and the means of assigning attributes to each criterion is discussed in detail. In addition, the uncertainty in physical characteristics of the asteroid population is quantified through the use of Monte Carlo analysis. The Monte Carlo simulation provides insight into the performance robustness of the redirection methods with respect to the targeted asteroid range. Lastly, the attributes for each redirection method are aggregated using three different multicriteria assessment approaches, i.e., the analytical hierarchy process, a utility-based approach, and a fuzzy aggregation mechanism. The results of each assessment approach as well as recommendations for further studies are discussed in detail.

  • 5.
    Bohra, Murtaza M.
    et al.
    Space Mechatronics Group, Institute for Aerospace Studies, University of Toronto.
    Xu, Linsen
    Space Mechatronics Group, Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    CPG-based online trajectory generation for quadruped rovers2016In: 2015 IEEE International Conference on Robotics and Biomimetics (ROBIO): Zhuhai, 6-9 Dec. 2015, Piscataway, NJ: IEEE Communications Society, 2016, 1053-1058 p., 7418911Conference paper (Refereed)
    Abstract [en]

    Legged rovers are often considered as viable solutions for traversing unknown terrain. A 2D sagittal plane rover model, based on a domestic cat, is considered in this paper, and an online model-free gait planning framework is implemented using Central Pattern Generators. The framework is used to generate joint trajectories for any arbitrarily varying speed profile, and regulate locomotion transition and speed modulation, both continuously and endogenously. For a continuously changing speed profile, the gait transition is continuous as well. For a discontinuously changing speed profile, a hopping motion is observed, because the rover's thrust speed cannot increase discontinuously

  • 6.
    Browne Mwakyanjala, Moses
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Beek, Jaap van de
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Software-defined radio transceiver for QB50 CubeSat telemetry and telecommand2016In: Proceedings of the 34th AIAA International Communications Satellite Systems Conference (ICSSC 2016), American Institute of Aeronautics and Astronautics, 2016Conference paper (Refereed)
    Abstract [en]

    This paper presents the development of a ground system based on software-defined radio for supporting both ground testing and space telemetry and telecommand of one of the nanosatellites in the QB50 mission. The QB50 project is an ongoing European Commission Seventh Framework initiative, which aims at launching a constellation of 50 CubeSats in the lower thermosphere to carry out in-situ scientific measurements. The paper discusses the implementation of amateur radio protocols and telecommunication modulation schemes on the ground system. The system setup, deployment and scheduling are also discussed using two separate ground stations. The use of different software for testing the system is detailed, the results show the operability of the developed ground system. © 2016, American Institute of Aeronautics and Astronautics Inc

  • 7.
    Browne Mwakyanjala, Moses
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Verication of phase and frequency modulation for software-defined radio baseband systems using field data2017Conference paper (Refereed)
  • 8.
    Chhabra, Robin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Institute for Aerospace Studies, University of Toronto.
    A generalized exponential formula for forward and differential kinematics of open-chain multi-body systems2014In: Mechanism and machine theory, ISSN 0094-114X, E-ISSN 1873-3999, Vol. 73, 61-75 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a generalized exponential formula for Forward and Differential Kinematics of open-chain multi-body systems with multi-degree-of-freedom, holonomic and nonholonomic joints. The notion of lower kinematic pair is revisited, and it is shown that the relative configuration manifolds of such joints are indeed Lie groups. Displacement subgroups, which correspond to different types of joints, are categorized accordingly, and it is proven that except for one class of displacement subgroups the exponential map is surjective. Screw joint parameters are defined to parameterize the relative configuration manifolds of displacement subgroups using the exponential map of Lie groups. For nonholonomic constraints the admissible screw joint speeds are introduced, and the Jacobian of the open-chain multi-body system is modified accordingly. Computational aspects of the developed formulation for Forward and Differential Kinematics of open-chain multi-body systems are explored by assigning coordinate frames to the initial configuration of the multi-body system, employing the matrix representation of SE(3) and choosing a basis for se(3). Finally, an example of a mobile manipulator mounted on a spacecraft, i.e., a six-degree-of-freedom moving base, elaborates the computational aspects. © 2013 Elsevier Ltd.

  • 9.
    Chhabra, Robin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Institute for Aerospace Studies, University of Toronto.
    A holistic approach to concurrent engineering and its application to robotics2014In: Concurrent Engineering - Research and Applications, ISSN 1063-293X, E-ISSN 1531-2003, Vol. 22, no 1, 48-61 p.Article in journal (Refereed)
    Abstract [en]

    This article details a holistic concurrent design framework, based on fuzzy logic, which is suitable for multidisciplinary systems. The methodology attempts to enhance communication and collaboration between different disciplines through introducing the universal notion of satisfaction and expressing the holistic behavior of multidisciplinary systems using the notion of energy. Throughout the design process, it uses fuzzy logic to formalize subjective aspects of design including the impact of the designer's attitude, resulting in the simplification of the multi-objective constrained optimization process. In the final phase, the methodology adjusts the designer's subjective attitude based on a holistic system performance by utilizing an energy-based model of multidisciplinary systems. The efficiency of the resulting design framework is illustrated by improving the design of a 5-degree-of-freedom industrial robot manipulator. © The Author(s) 2013.

  • 10.
    Chhabra, Robin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Institute for Aerospace Studies, University of Toronto.
    A holistic concurrent design approach to robotics using hardware-in-the-loop simulation2013In: Mechatronics (Oxford), ISSN 0957-4158, E-ISSN 1873-4006, Vol. 23, no 3, 335-345 p.Article in journal (Refereed)
    Abstract [en]

    This paper discusses a practical approach to the concurrent design of robot manipulators, which is based on an alternative design methodology, namely Holistic Concurrent Design (HCD), as well as the utilization of a modular hardware-in-the-loop simulation. Holistic concurrent design is a systematic design methodology for mechatronic systems that formalizes subjective notions of design, resulting in the simplification of the multi-objective constrained optimization process. Its premise is to enhance the communication between designers with various backgrounds and customers, and to consider numerous design variables with different natures concurrently. The methodology redefines the ultimate goal of design based on the qualitative notion of satisfaction, and formalizes the effect of designer's subjective attitude in the process. The hardware-in-the-loop platform involves physical joint modules and the control unit of a manipulator in addition to the software simulation to reduce modeling complexities and to take into account physical phenomena that are hard to be captured mathematically. This platform is implemented in the HCD design architecture to reliably evaluate the design attributes and performance supercriterion during the design process. The resulting architecture is applied to redesigning kinematic, dynamic and control parameters of an industrial manipulator. Copyright © 2013 Published by Elsevier Ltd. All rights reserved.

  • 11.
    Chhabra, Robin
    et al.
    Department of Mathematics and Statistics, University of Calgary.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    A linguistic approach to concurrent design2015In: Journal of Intelligent & Fuzzy Systems, ISSN 1064-1246, E-ISSN 1875-8967, Vol. 28, no 5, 1985-2001 p.Article in journal (Refereed)
    Abstract [en]

    This paper outlines a concurrent design methodology for multidisciplinary systems, which employs tools of fuzzy theory for the tradeoff in the design space. This methodology enhances communication between designers from various disciplines through introducing the universal notion of satisfaction and expressing the behaviour of multidisciplinary systems using the notion of energy. It employs fuzzy rule-bases, membership functions and parametric connectives in fuzzy logic to formalize subjective aspects of design, resulting in a two-phase simplification of the multi-objective constrained optimization of a design process. The methodology attempts to find a pareto-optimal solution for the design problem. In the primary phase of the methodology, a fuzzy-logic model is utilized to identify a region in the design space that contains the pareto-optimal design state, and a proper initial state is suggested for the optimization in the secondary phase, where the pareto-optimal solution is found. Finally, the impact of the designer's subjective attitude on the design is adjusted based on a system performance by utilizing an energy-based model of multidisciplinary systems. As an application, it is shown that the design of a five-degree-of-freedom industrial robot manipulator can be enhanced by using the methodology.

  • 12.
    Chhabra, Robin
    et al.
    MacDonald, Dettwiler and Associates Ltd., Brampton.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    A Unified Approach to Input-output Linearization and Concurrent Control of Underactuated Open-chain Multi-body Systems with Holonomic and Nonholonomic Constraints2016In: Journal of dynamical and control systems, ISSN 1079-2724, E-ISSN 1573-8698, Vol. 22, no 1, 129-168 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a unified geometric framework to input-output linearization of open-chain multi-body systems with symmetry in their reduced phase space. This leads us to an output tracking controller for a class of underactuated open-chain multi-body systems with holonomic and nonholonomic constraints. We consider the systems with multi-degree-of-freedom joints and possibly with non-zero constant total momentum (in the holonomic case). The examples of these systems are free-base space manipulators and mobile manipulators. We first formalize the control problem, and rigorously state an output tracking problem for such systems. Then, we introduce a geometrical definition of the end-effector pose and velocity error. The main contribution of this paper is reported in Section 5, where we solve for the input-output linearization of the highly nonlinear problem of coupled manipulator and base dynamics subject to holonomic and nonholonomic constraints. This enables us to design a coordinate-independent controller, similar to a proportional-derivative with feed-forward, for concurrently controlling a free-base, multi-body system. Finally, by defining a Lyapunov function, we prove in Theorem 3 that the closed-loop system is exponentially stable. A detailed case study concludes this paper.

  • 13.
    Chhabra, Robin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Institute for Aerospace Studies, University of Toronto.
    Concurrent synthesis of robot manipulators using hardware-in-the-loop simulation2009In: IEEE International Conference on Robotics and Automation, ICRA, Kobe, Japan, 12-17 May 2009, Piscataway, NJ: IEEE Communications Society, 2009, 568-573 p., 5152416Conference paper (Refereed)
    Abstract [en]

    This paper discusses a practical approach to the concurrent synthesis of robot manipulators, which is based on the alternative design methodology of Linguistic Mechatronics (LM) as well as the utilization of a modular Robotic Hardwarein- the-loop Simulation (RHILS) platform. The RHILS platform involves physical joint modules and the control unit to reduce modeling complexities while taking into account various physical phenomena. The LM methodology simplifies the multi-objective constrained optimization problem into a singleobjective unconstrained formulation and also brings subjective notions of design into the scope. The new approach is applied to redesigning kinematic, dynamic and control parameters of an industrial manipulator. © 2009 IEEE.

  • 14.
    Chhabra, Robin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Institute for Aerospace Studies, University of Toronto.
    Holistic system modeling in mechatronics2011In: Mechatronics (Oxford), ISSN 0957-4158, E-ISSN 1873-4006, Vol. 21, no 1, 166-175 p.Article in journal (Refereed)
    Abstract [en]

    This paper outlines an alternative modeling scheme for mechatronic systems, as a basis for their concurrent design. The approach divides a mechatronic system into three generic subsystems, namely generalized executive, sensory and control, and links them together utilizing a combination of bond graphs and block diagrams. It considers the underlying principles of a multidisciplinary system, and studies the flow of energy and information throughout its different constituents. The first and second laws of thermodynamics are reformulated for mechatronic systems, and as a result three holistic design criteria, namely energy, entropy and agility, are defined. These criteria are formulated using the bond graph representation of a mechatronic system. As a case study, the three criteria are employed separately for concurrent design of a five degree-of-freedom industrial robot manipulator. © 2010 Elsevier Ltd. All rights reserved.

  • 15.
    Chhabra, Robin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Institute for Aerospace Studies, University of Toronto.
    Linguistic mechatronics2008In: IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM, Xi'an, China, 2-5 July 2008, Piscataway, NJ: IEEE Communications Society, 2008, 1315-1320 p., 4601852Conference paper (Refereed)
    Abstract [en]

    This paper outlines a systematic design methodology for mechatronic systems, which formalizes subjective notions and simplifies the optimization process, in the hope that communication between designers with various backgrounds and clients is enhanced and numerous design variables with different natures can be considered concurrently. The methodology redefines the ultimate goal of design based on the qualitative notions of wish and must satisfaction, and formalizes the effect of designer's subjective attitude in the process, which can be adjusted based on the reality of system performance. © 2008 IEEE.

  • 16.
    Chhabra, Robin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Institute for Aerospace Studies, University of Toronto.
    Nonholonomic dynamical reduction of open-chain multi-body systems: A geometric approach2014In: Mechanism and machine theory, ISSN 0094-114X, E-ISSN 1873-3999, Vol. 82, 231-255 p.Article in journal (Refereed)
    Abstract [en]

    This paper studies the geometry behind nonholonomic Hamilton's equation to present a two-stage reduction procedure for the dynamical equations of nonholonomic open-chain multi-body systems with multi-degree-of-freedom joints. In this process, we use the Chaplygin reduction and an almost symplectic reduction theorem. We first restate the Chaplygin reduction theorem on cotangent bundle for nonholonomic Hamiltonian mechanical systems with symmetry. Then, under some conditions we extend this theorem to include a second reduction stage using an extended version of the symplectic reduction theorem for almost symplectic manifolds. We briefly introduce the displacement subgroups and accordingly open-chain multi-body systems consisting of such joints. For a holonomic open-chain multi-body system, the relative configuration manifold corresponding to the first joint is a symmetry group. Hence, we focus on a class of nonholonomic distributions on the configuration manifold of an open-chain multi-body system that is invariant under the action of this group. As the first stage of reduction procedure, we perform the Chaplygin reduction for such systems. We then introduce a number of sufficient conditions for a reduced system to admit more symmetry due to the action of the relative configuration manifolds of other joints. Under these conditions, we present the second stage of the reduction process for nonholonomic open-chain multi-body systems with multi-degree-of-freedom joints. Finally, we explicitly derive the reduced dynamical equations in the local coordinates for an example of a two degree-of-freedom crane mounted on a four-wheel car to illustrate the results of this paper.

  • 17.
    Chhabra, Robin
    et al.
    Institute for Aerospace Studies, University of Toronto, MacDonald, Dettwiler and Associates Ltd., Brampton.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Symplectic reduction of holonomic open-chain multi-body systems with constant momentum2015In: Journal of Geometry and Physics, ISSN 0393-0440, E-ISSN 1879-1662, Vol. 89, 82-110 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a two-step symplectic geometric approach to the reduction of Hamilton's equation for open-chain, multi-body systems with multi-degree-of-freedom holonomic joints and constant momentum. First, symplectic reduction theorem is revisited for Hamiltonian systems on cotangent bundles. Then, we recall the notion of displacement subgroups, which is the class of multi-degree-of-freedom joints considered in this paper. We briefly study the kinematics of open-chain multi-body systems consisting of such joints. And, we show that the relative configuration manifold corresponding to the first joint is indeed a symmetry group for an open-chain multi-body system with multi-degree-of-freedom holonomic joints. Subsequently using symplectic reduction theorem at a non-zero momentum, we express Hamilton's equation of such a system in the symplectic reduced manifold, which is identified by the cotangent bundle of a quotient manifold. The kinetic energy metric of multi-body systems is further studied, and some sufficient conditions are introduced, under which the kinetic energy metric is invariant under the action of a subgroup of the configuration manifold. As a result, the symplectic reduction procedure for open-chain, multi-body systems is extended to a two-step reduction process for the dynamical equations of such systems. Finally, we explicitly derive the reduced dynamical equations in the local coordinates for an example of a six-degree-of-freedom manipulator mounted on a spacecraft, to demonstrate the results of this paper. (C) 2014 Elsevier B.V. All rights reserved.

  • 18.
    Chhabra, Robin
    et al.
    MacDonald, Dettwiler and Ass. Ltd.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Karshon, Yael
    Department of Mathematics, University of Toronto.
    Reduction of Hamiltonian Mechanical Systems With Affine Constraints: A Geometric Unification2017In: Journal of Computational and Nonlinear Dynamics, ISSN 1555-1415, E-ISSN 1555-1423, Vol. 12, no 2, 021007Article in journal (Refereed)
    Abstract [en]

    This paper presents a geometrical approach to the dynamical reduction of a class of constrained mechanical systems. The mechanical systems considered are with affine nonholonomic constraints plus a symmetry group. The dynamical equations are formulated in a Hamiltonian formalism using the Hamilton-d'Alembert equation, and constraint forces determine an affine distribution on the configuration manifold. The proposed reduction approach consists of three main steps: (1) restricting to the constrained submanifold of the phase space, (2) quotienting the constrained submanifold, and (3) identifying the quotient manifold with a cotangent bundle. Finally, as a case study, the dynamical reduction of a two-wheeled rover on a rotating disk is detailed. The symmetry group for this example is the relative configuration manifold of the rover with respect to the inertial space. The proposed approach in this paper unifies the existing reduction procedures for symmetric Hamiltonian systems with conserved momentum, and for Chaplygin systems, which are normally treated separately in the literature. Another characteristic of this approach is that although it tracks the structure of the equations in each reduction step, it does not insist on preserving the properties of the system. For example, the resulting dynamical equations may no longer correspond to a Hamiltonian system. As a result, the invariance condition of the Hamiltonian under a group action that lies at the heart of almost every reduction procedure is relaxed

  • 19.
    Ekman, Jonas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Antti, Marta-Lena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Törlind, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Kuhn, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nilsson, Hans
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Öhrwall Rönnbäck, Anna
    Gustafsson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Zorzano Mier, Maria-Paz
    Milz, Mathias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Parida, Vinit
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Behar, Etienne
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Wolf, Veronika
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Dordlofva, Christo
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Mendaza de Cal, Maria Teresa
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Jamali, Maryam
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Roos, Tobias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Ottemark, Rikard
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nieto, Chris
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Soria Salinas, Álvaro Tomás
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Vázquez Martín, Sandra
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nyberg, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Neikter, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Lindwall, Angelica
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Fakhardji, Wissam
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Projekt: Rymdforskarskolan2015Other (Other (popular science, discussion, etc.))
    Abstract [en]

    The Graduate School of Space Technology

  • 20.
    Emami, Reza
    University of Toronto.
    Application of learning models to the engineering design pedagogy2009In: ASEE Annual Conference and Exposition, Austin, USA, 14-17 June 2009: Conference Proceedings, 2009Conference paper (Refereed)
    Abstract [en]

    This paper discusses the implementation of a hybrid framework for teaching cornerstone design courses based on the behaviourist and constructivist learning models, which ensures adequate instruction and scaffolding while students develop their design knowledge through hands-on projects. The instructional design methodology is based on the Elaboration Theory that allows a gradual transition from content-based instruction to project-based knowledge construction. The practical steps are detailed for a full-year design course at the sophomore level. © American Society for Engineering Education, 2009.

  • 21.
    Emami, Reza
    University of Toronto.
    Multidisciplinary Engineering Design: From Theory to Practice2014 (ed. 15)Book (Refereed)
  • 22.
    Emami, Reza
    University of Toronto.
    Numerical Computing With Simulink, Volume I: Creating Simulations2009In: Journal of the American Statistical Association, ISSN 0162-1459, E-ISSN 1537-274X, Vol. 63, no 3, 285- p.Article in journal (Refereed)
  • 23.
    Emami, Reza
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Bazzocchi, Michael C. F.
    Institute for Aerospace Studies, University of Toronto.
    Low-thrust orbit transfer of Arjuna-type asteroids2016In: AIAA/AAS Astrodynamics Specialist Conference, 2016, American Institute of Aeronautics and Astronautics, 2016Conference paper (Refereed)
    Abstract [en]

    This paper investigates the accessible low-thrust transfer trajectories for a near-Earth asteroid transfer mission. The target asteroids considered are Arjuna type asteroids, which are characterized by their Earth-like orbital paths including low-eccentricity and low-inclination. The asteroid range is characterized by specific semi-major axes and transfer angles to provide an overall assessment of the potential Arjuna transfer domain. A single hovering ion beam spacecraft is employed for the task of asteroid redirection. The method utilizes a continuous thrust over the duration of the transfer maneuver to redirect the asteroid to an Earth bound orbit. The transfer model employs a minimized form of Gauss's variational equations to determine the available trajectories for asteroid redirection. The transfer model employs, in addition to the aforementioned orbital equations, spacecraft thruster and sizing metrics, as well as mission cost analysis formulae. The system parameters and orbital transfer paths are assessed with regards to key mission parameters, namely, timeframe for redirection, number of orbital revolutions, system mass, propellant mass, thrust, power, system cost, and financial return rate

  • 24.
    Emami, Reza
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Chhabra, Robin
    Institute for Aerospace Studies, University of Toronto.
    Concurrent Engineering of Robot Manipulators2010In: Robot Manipulators New Achievements, Wien: I-Tech Education and Publishing KG, 2010, 211-240 p.Chapter in book (Refereed)
  • 25.
    Emami, Reza
    et al.
    University of Toronto.
    Goldenberg, Andrew A.
    University of Toronto.
    Turksen, I. Burhan
    University of Toronto.
    Fuzzy-logic dynamics modeling of robot manipulators1998In: 1998 IEEE International Conference on Robotics and Automation, Leuven, Belgium, 16-20 May 1998: Proceedings, Piscataway, NJ: IEEE Communications Society, 1998, Vol. 3, 2512-2517 p.Conference paper (Refereed)
    Abstract [en]

    A systematic approach of fuzzy-logic modeling from the system input-output data is applied to modeling dynamics behavior of a four degree-of-freedom robot manipulator. The output of the fuzzy model is compared with the experimental data and with that of an analytical simulation. The simplicity of the fuzzy model and its improved accuracy is significant.

  • 26.
    Emami, Reza
    et al.
    University of Toronto.
    Goldenberg, Andrew A.
    University of Toronto.
    Turksen, I. Burhan
    University of Toronto.
    Robust model-based fuzzy-logic controller for robot manipulators1998In: 1998 IEEE International Conference on Robotics and Automation, Leuven, Belgium, 16-20 May 1998: Proceedings, Piscataway, NJ: IEEE Communications Society, 1998, Vol. 3, 2500-2505 p.Conference paper (Refereed)
    Abstract [en]

    This paper represents a fuzzy-logic control structure, containing the fuzzy-logic model of the dynamic system and fuzzy control rules that ensure the stability and robust performance. The robust fuzzy rules are designed based on a generalized formulation of sliding mode control for a class of nonlinear multi-input multi-output systems. The proposed fuzzy-logic control scheme was applied to the trajectory control of a four degree-of-freedom robot, and compared with the high-gain PID controllers. A superior tracking performance was achieved.

  • 27.
    Emami, Reza
    et al.
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Goldenberg, Andrew A.
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Türksen, I. Burhan
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Systematic design and analysis of fuzzy-logic control and application to robotics: Part 1. Modeling2000In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 33, no 2-3, 65-88 p.Article in journal (Refereed)
    Abstract [en]

    A systematic methodology for synthesis and analysis of fuzzy-logic controllers is proposed in this paper (Part I) and its follow up (Part II) [M.R. Emami, et al., Robotics and Autonomous Systems 33 (2000) 89–108]. A robust model-based control structure is suggested that includes a fuzzy-logic inverse dynamics model and several robust fuzzy control rules. The model encapsulates the knowledge of the system dynamics in the form of IF–THEN rules. The paper focuses on how to obtain this knowledge systematically from the input–output data of a complex system; one that is ill-defined or contains complicated phenomena that are difficult to interpret analytically. All practical steps, from data acquisition to model validation, are illustrated using a four degree-of-freedom robot manipulator. Comparing the results with those of a complete analytical model and a heuristic fuzzy modeling technique illustrates the strength of the proposed methodology in terms of capturing effects that are difficult to model. In the follow-up paper, this model is used in the proposed control structure.

  • 28.
    Emami, Reza
    et al.
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Goldenberg, Andrew A.
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Türksen, I. Burhan
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Systematic design and analysis of fuzzy-logic control and application to robotics: Part II. Control2000In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 33, no 2-3, 89-108 p.Article in journal (Refereed)
    Abstract [en]

    This paper (Part II) follows the task of systematic synthesis and analysis of fuzzy-logic control (FLC) systems introduced in Part I [M.R. Emami, et al., Robotics and Autonomous Systems 33 (2000) 65–88]. First, a generalized formulation of the sliding mode control is obtained for a class of nonlinear multi-input–multi-output systems. This formulation has two distinguishing features that are necessary for the formulation of the proposed approach: (i) it is applicable to “black box” systems with no need to identify the internal parameters or to assume a specific structure; (ii) it is possible to design the robust controller for each system state independently while the stability and robustness of the entire system is guaranteed. The robust fuzzy control rules are designed based on the generalized formulation to guarantee the stability and satisfactory system performance. The proposed FLC has been applied to trajectory control of the four degree-of-freedom IRIS arm (Emami et al., 2000), and was compared with high-gain PID controllers. A superior tracking performance was achieved.

  • 29.
    Emami, Reza
    et al.
    Space Mechatronics group, Aerospace and Design Laboratories, University of Toronto.
    Helander, Michael G.
    Department of Materials Science, University of Toronto.
    An outline of eDesign2010In: ASEE Annual Conference and Exposition, Louisville, USA, 20-23 June 2010: Conference Proceedings, 2010Conference paper (Refereed)
    Abstract [en]

    This paper discusses the relevance of distance learning to the engineering design education. Some key characteristics of design pedagogy seem to fall beyond the scope of current content-based eLearning solutions, including contextual social and collaborative interaction and iterative experimentation. Consequently, an effective eLearning solution for design pedagogy must bridge the gap between the physical and virtual worlds by establishing a virtual collaborative community and providing students with remote access to software and hardware resources. The paper outlines a comprehensive architecture of the eDesign portal that integrates the traditional courseware technology with remotely-accessible hardware-in-the-loop simulation, eCollaboration, and virtual classroom and learning community. The required hardware and software for implementing the eDesign architecture are detailed, and a preliminary assessment of using the eDesign portal for a second-year design course is discussed. © American Society for Engineering Education, 2010.

  • 30.
    Emami, Reza
    et al.
    Aero-Design Undergraduate Laboratories, Institute for Aerospace Studies, University of Toronto.
    Kereluk, Jason
    Space Mechatronics Group, Institute for Aerospace Studies, University of Toronto.
    A remotely-accessible reconfigurable platform for robotics education2013In: ASEE Annual Conference and Exposition, Atlanta, USA, 23-26 June 2013: Conference Proceedings, 2013Conference paper (Refereed)
    Abstract [en]

    This paper discusses a new remotely-Accessible, serial-manipulator platform for robotics education. The hardware is an 18 degree of freedom manipulator that can lock any combination of its joints in any position in their continuous range to emulate a manipulator with fewer degrees of freedom. The manipulator is controlled by an integrated design and simulation environment running on a host workstation, which links through a target processor to the manipulator hardware. The software application is remotely accessible by students via an eLaboratory portal, which manages students' remote experimentation and on-line collaboration. The purpose of this system is to provide a unified educational platform with which students can experience a wide range of serial-manipulator configurations without the need of multiple hardware setups. © American Society for Engineering Education, 2013.

  • 31.
    Emami, Reza
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Institute for Aerospace Studies, University of Toronto.
    Kereluk, Jason Alexander
    Space Mechatronics Group, Institute for Aerospace Studies, University of Toronto.
    System, method and computer program for autonomously emulating robot manipulators of continuously-varying configurationsPatent (Other (popular science, discussion, etc.))
    Abstract [en]

    The invention is a modular and autonomously reconfigurable manipulator system which introduces a new dimension to the versatility of robot manipulation for diverse tasks. The hardware component is a redundant mechanism which can lock any number of its joints at any relative position to form a particular configuration with a certain number of degrees of freedom and specific values for kinematic, dynamic and control parameters, optimum for a given task to be performed. The process of identifying the optimum configuration for a given task and implementing it on the manipulator is done autonomously through the system software. Therefore, no manual interaction is required to form a new configuration most suitable for a given task. The kinematic, dynamic and control parameters of the system can vary continuously enabling the manipulator to form virtually an infinite number of configurations.

  • 32.
    Emami, Reza
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Mousavi, S Fazlolah
    Department of Aerospace Engineering, K.N.T University of Technology, Tehran.
    Roshanian, Jafar
    Department of Aerospace Engineering, K.N.T University of Technology, Tehran.
    Quaternion-based attitude control design and hardware-in-the-loop simulation of suborbital modules with cold gas thrusters2015In: Journal of Aerospace Engineering, ISSN 0893-1321, E-ISSN 1943-5525, Vol. 229, no 4, 717-735 p.Article in journal (Refereed)
    Abstract [en]

    This paper discusses design and implementation of a quaternion-based attitude control system for the short-duration mission of suborbital modules using cold-gas thrusters. The quaternion-based controller generates a command torque for each channel, and a pulse-width pulse-frequency (PWPF) modulator determines the required fire signals for the thrusters. The system performance is examined through both numerical and hardware-in-the-loop simulations.

  • 33.
    Emami, Reza
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Ng, Larry
    Institute for Aerospace Studies, University of Toronto.
    Concurrent Individual And Social Learning In Robot Teams2016In: Computational intelligence, ISSN 0824-7935, E-ISSN 1467-8640, Vol. 32, no 3, 420-438 p.Article in journal (Refereed)
    Abstract [en]

    This article discusses effective mechanisms that enable a group of robots to autonomously generate, adapt, and enhance team behaviors while improving their individual performance simultaneously. Two promising team learning concepts, namely, cooperative learning and advice-sharing, are integrated to provide a platform that encompasses a comprehensive approach to team-performance enhancement. These methods were examined in relation to the performance characteristics of standard single-robot Q-learning to ascertain whether they retain viable learning characteristics despite the integration of individual learning into team behaviors

  • 34.
    Emami, Reza
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Ragusila, Victor
    Institute for Aerospace Studies, University of Toronto.
    Mechatronics by analogy and application to legged locomotion2016In: Mechatronics (Oxford), ISSN 0957-4158, E-ISSN 1873-4006, Vol. 35, 173-191 p.Article in journal (Refereed)
    Abstract [en]

    A new design methodology for mechatronic systems, dubbed as Mechatronics by Analogy (MbA), is introduced. It argues that by establishing a similarity relation between a complex system and a number of simpler models it is possible to design the former using the analysis and synthesis means developed for the latter. The methodology provides a framework for concurrent engineering of complex systems while maintaining the transparency of the system behavior through making formal analogies between the system and those with more tractable dynamics. The application of the MbA methodology to the design of a monopod robot leg, called the Linkage Leg, is also presented. A series of simulations show that the dynamic behavior of the Linkage Leg is similar to that of a combination of a double pendulum and a spring-loaded inverted pendulum, based on which the system kinematic, dynamic, and control parameters can be designed concurrently.

  • 35.
    Emami, Reza
    et al.
    Space Mechatronics Group, Institute for Aerospace Studies, University of Toronto.
    Tedesco, Michael Anthony
    Space Mechatronics Group, Institute for Aerospace Studies, University of Toronto.
    A modular and turn-key remote-access hardware-in-the-loop platform for testing electric motors2014In: Journal of Advanced Mechanical Design, Systems, and Manufacturing, ISSN 1881-3054, E-ISSN 1881-3054, Vol. 8, no 1Article in journal (Refereed)
    Abstract [en]

    This paper details the architecture, hardware and software of a platform for testing electric motors over the Internet that enables users to test multiple physical motors remotely under the specific loading conditions of the real-world application for which a motor is required. The system is divided into three major modules: the Server Software Application, the Target Software Application and the Motor Test Platform. The system is unique as it combines modularity, scalability and deliverability. It is modular, as it is capable of readily testing a variety of electric motors, scalable, as new motors can be quickly added to the system for testing, and is turn-key, easily deployed and installed. The proof-of-concept prototype was developed and examined against benchmark tests to determine its capabilities. The platform was effective as a remote access emulation and evaluation tool.

  • 36.
    Emami, Reza
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Institute for Aerospace Studies, University of Toronto.
    Tedesco, Michael Anthony
    Space Mechatronics Group, University of Toronto, Toronto.
    System, method and computer program for remotely testing system components over a networkPatent (Other (popular science, discussion, etc.))
    Abstract [en]

    The invention is a turn-key, modular platform, including software and hardware, for testing physical system components such as motors remotely over the Internet. The system allows remote customers to test multiple physical system components under the specific loading conditions of the real-world application. This will provide more detailed and accurate information than what is usually given in the data sheets for system component performance, enabling the user to make a more-reliable decision. With respect to motors, the hardware consists of a torque motor that moves autonomously in xy plane to couple to the individual test motors, through a unique coupling mechanism, and emulate various load profiles on them. Test motors are mounted onto modular fixtures that allow for one-time manual positioning in xyz space. The software, consisting of server and target applications, creates user accounts and profiles, controls user access by means of a scheduler, and enables each user to connect to the hardware via Internet and run a customized experiment.

  • 37.
    Felicetti, Leonard
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    A multi-spacecraft formation approach to space debris surveillance2016In: Acta Astronautica, ISSN 0094-5765, E-ISSN 1879-2030, Vol. 127, 491-504 p.Article in journal (Refereed)
    Abstract [en]

    This paper proposes a new mission concept devoted to the identification and tracking of space debris through observations made by multiple spacecraft. Specifically, a formation of spacecraft has been designed taking into account the characteristics and requirements of the utilized optical sensors as well as the constraints imposed by sun illumination and visibility conditions. The debris observations are then shared among the team of spacecraft, and processed onboard of a “hosting leader” to estimate the debris motion by means of Kalman filtering techniques. The primary contribution of this paper resides on the application of a distributed coordination architecture, which provides an autonomous and robust ability to dynamically form spacecraft teams once the target has been detected, and to dynamically build a processing network for the orbit determination of space debris. The team performance, in terms of accuracy, readiness and number of the detected objects, is discussed through numerical simulations.

  • 38.
    Felicetti, Leonard
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Attitude Coordination of Multiple Spacecraft for Space Debris Surveillance2017In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 59, no 5, 1270-1288 p.Article in journal (Refereed)
    Abstract [en]

    This paper discusses the attitude coordination of a formation of multiple spacecraft for space debris surveillance. Off-the-shelf optical sensors and reaction wheels, with limited field of view and control torque, respectively, are considered to be used onboard the spacecraft for performing the required attitude maneuvers to detect and track space debris. The sequence of attitude commands are planned by a proposed algorithm, which allows for a dynamic team formation, as well as performing suitable maneuvers to eventually point towards the same debris. A control scheme based on the nonlinear state dependent Riccati equation is designed and applied to the space debris surveillance mission scenario, and its performance is compared with those of the classic linear quadratic regulator and quaternion feedback proportional derivative controllers. The viability and performance of the coordination algorithm and the controllers are validated through numerical simulations.

  • 39.
    Felicetti, Leonard
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Spacecraft formation for debris surveillance2017In: IEEE Aerospace Conference Proceedings, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, 7943750Conference paper (Refereed)
    Abstract [en]

    This paper explores the viability and performance of a new algorithm for in-orbit space debris surveillance, which utilizes a network of distributed optical sensors carried onboard multiple spacecraft flying in formation. The resulting network of spacecraft is able to autonomously detect unknown debris, as well as track the existing ones, estimate their trajectories, and send the estimation results directly to the mission control centers for planning the required collision avoidance maneuvers. The proposed concept includes (a) an estimation algorithm that allows for sharing observations of common debris objects among spacecraft; (b) a coordination algorithm for the re-orientation of an ad hoc team of spacecraft to align their onboard optical sensors towards common targets; and (c) a control algorithm for the detection and tracking of the debris which uses vision-based attitude maneuvers.

  • 40.
    Garg, Kanika
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. kanika.garg@ltu.se .
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Aerobot design for planetary explorations2016In: AIAA Space and Astronautics Forum and Exposition, SPACE 2016, American Institute of Aeronautics and Astronautics, 2016Conference paper (Refereed)
    Abstract [en]

    This paper studies the design of planetary aerobots with different types and shapes under various atmospheric conditions. The design framework and specifications are discussed. The development of a simulation tool is described, which is used for analyzing the behaviour of aerobots on Venus, Mars and Titan. The software is verified through the comparison of its performance with some experimental data as well as the state-of-the-art simulation tools. Based on the simulation results, some recommendations are made for different aerobot exploration missions

  • 41.
    Girard, Justin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    A robust approach to robot team learning2016In: Autonomous Robots, ISSN 0929-5593, E-ISSN 1573-7527, Vol. 40, no 8, 1441-1457 p.Article in journal (Refereed)
    Abstract [en]

    The paper achieves two outcomes. First, it summarizes previous work on concurrent Markov decision processes (CMDPs) currently demonstrated for use with multi-agent foraging problems. When using CMDPs, each agent models the environment using two Markov decision process (MDP). The two MDPs characterize a multi-agent foraging problem by modeling both a single-agent foraging problem, and multi-agent task allocation problem, for each agent. Second, the paper studies the effects of state uncertainty on a heterogeneous robot team that utilizes the aforementioned CMDP modelling approach. Furthermore, the paper presents a method to maintain performance despite state uncertainty. The resulting robust concurrent individual and social learning (RCISL) mechanism leads to an enhanced team learning behaviour despite state uncertainty. The paper analyzes the performance of the concurrent individual and social learning mechanism with and without a particle filter for a heterogeneous foraging scenario. The RCISL mechanism confers statistically significant performance improvements over the CISL mechanism

  • 42.
    Girard, Justin
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Concurrent Markov decision processes for robot team learning2015In: Engineering applications of artificial intelligence, ISSN 0952-1976, E-ISSN 1873-6769, Vol. 39, 223-234 p., 12Article in journal (Refereed)
    Abstract [en]

    Multi-agent learning, in a decision theoretic sense, may run into deficiencies if a single Markov decision process (MDP) is used to model agent behaviour. This paper discusses an approach to overcoming such deficiencies by considering a multi-agent learning problem as a concurrence between individual learning and task allocation MDPs. This approach, called Concurrent MDP (CMDP), is contrasted with other MDP models, including decentralized MDP. The individual MDP problem is solved by a Q-Learning algorithm, guaranteed to settle on a locally optimal reward maximization policy. For the task allocation MDP, several different concurrent individual and social learning solutions are considered. Through a heterogeneous team foraging case study, it is shown that the CMDP-based learning mechanisms reduce both simulation time and total agent learning effort.

  • 43.
    Goldenberg, Andrew A.
    et al.
    University of Toronto.
    Emami, Reza
    University of Toronto.
    Kinematics and Dynamics of Robot Manipulators1999In: Handbook of Industrial Robotics, Hoboken: John Wiley & Sons Ltd , 1999, 2, 79-98 p.Chapter in book (Refereed)
  • 44.
    Goldenberg, Andrew A.
    et al.
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Türksen, I. Burhan
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Emami, Reza
    Department of Mechanical and Industrial Engineering, University of Toronto.
    Fuzzy-logic control of dynamic systems: From modeling to design2000In: Engineering applications of artificial intelligence, ISSN 0952-1976, E-ISSN 1873-6769, Vol. 13, no 1, 47-69 p.Article in journal (Refereed)
    Abstract [en]

    A systematic methodology for the synthesis and analysis of fuzzy-logic controllers for multi-input multi-output nonlinear dynamic systems is proposed in this paper. A robust model-based control structure is suggested that includes the fuzzy-logic dynamics model of the system and several robust fuzzy control rules. The fuzzy-logic model is systematically constructed from the input-output data, and the robust control rules are designed using the sliding-mode control theory. The stability and completeness of the control structure is guaranteed, based on a generalized formulation of the sliding-mode control developed in this paper. The proposed fuzzy-logic control scheme has been applied to trajectory control of a four-degree-of-freedom robot manipulator, and was compared with high-gain PID controllers. Superior tracking performance was achieved.

  • 45.
    Hakima, Houman
    et al.
    University of Toronto Institute for Aerospace Studies, 4925 Dufferin Street, Toronto.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Debris detumbler: An alternative approach to active debris removal2016In: Proceedings of the International Astronautical Congress, IAC, 2016Conference paper (Refereed)
    Abstract [en]

    Since the launch of the first artificial satellite, i.e., Sputnik in 1957, several thousand man-made objects have been launched into the Earth orbits, great majority of which remained in their orbit despite the termination of their mission. A number of viable solutions have been suggested in the research community for actively removing the orbital debris, some of which require the capturing of the debris, while others are contactless methods. A challenging aspect of capturing an orbital debris using any method is due to the tumbling motion of the debris. A majority of the suggested methods require zero or very low rates of debris attitude to perform successfully, or need to follow a synchronization phase with the debris before the capturing and removal operation. This is technically costly and challenging, if not infeasible. This paper proposes an alternative approach to orbital debris removal, which can make various state-of-the-art methods of active debris removal perform at lower costs and risks. The approach utilizes one or more detumbler platforms, in the form of miniaturized cubesats, which are de-signed to be lunched from the remover spacecraft, attach to the target debris, and reduce its attitude rate to zero using the onboard attitude determination sensors and control actuators. The paper outlines the operation of debris detumblers. The conceptual design of such platforms is also presented, based on the one- to three-unit cubesat bus and commercial off-the-shelf technologies. Orbital insertion, rendezvous and attachment maneuvers are also discussed. Finally, through simulations the performance of the proposed approach is compared with that of some well-studied methods in various scenarios using several catalogued debris, based on performance metrics such as delta-v, operation time, trajectory simplicity, total thrust, etc

  • 46.
    Helander, Michael G.
    et al.
    Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Institute for Aerospace Studies, University of Toronto.
    Engineering eLaboratories: Integration of remote access and eCollaboration2008In: International Journal of Engineering ,Science and Innovative Technology, ISSN 0949-149X, E-ISSN 2277-3754, Vol. 24, no 3, 466-479 p.Article in journal (Refereed)
    Abstract [en]

    A significant portion of the development efforts on remote access laboratories has focused on demonstrating their technical feasibility instead of investigating their implications for engineering pedagogy. Further, current implementations of remote access laboratories lack the social interactions that are fundamental to the engineering learning process. In response to these limitations a new paradigm for remote access laboratories, namely the eLaboratory, is introduced in this paper, which is a convergence of remote access technologies and collaboration-based eLearning. It implements web-portal technology to establish a seamless integration of content-delivery, collaboration tools, and direct access to hardware resources as well as software applications. The paper presents a generic and modular architecture for such a framework, and discusses its implementation. Students' evaluation of the learning outcomes of the eLaboratory paradigm, applied to Aerospace Engineering laboratory courses at the University of Toronto, is also analyzed. © 2008 TEMPUS Publications.

  • 47.
    Helander, Michael G.
    et al.
    University of Toronto.
    Emami, Reza
    University of Toronto.
    The effects of computer interface on learning outcomes in remote access laboratories2009In: ASEE Annual Conference and Exposition, Austin, USA, 14-17 June 2009: Conference Proceedings, 2009Conference paper (Refereed)
    Abstract [en]

    Remote access laboratories are increasingly being integrated into undergraduate engineering curricula on a global scale. Despite the vast body of literature dealing with remotely-accessible laboratories, the majority of papers have focused on the technical merits of a particular implementation, rather than on the implications of remote access experimentation on engineering pedagogy. Recently, a few studies have attempted to quantify the effects of the remote access modality on students' learning outcomes. These initial pedagogical studies have indicated that there is indeed a difference between proximal and remote experimentation in terms of learning outcomes. However, the question still unanswered is if these observed differences are a result of the physical separation between student and hardware, or rather are a result of the computermediated interface used to control the remote hardware. This paper discusses the results of a comprehensive study comparing the pedagogical effects of remote vs. proximal experimentation that includes control over the effects of the computer-mediated interface. Two groups of students performed the same experiment proximally and remotely using the same computer interface, and the learning outcomes are examined. © American Society for Engineering Education, 2009.

  • 48.
    Houman, Hakima
    et al.
    University of Toronto, Institute for Aerospace Studies.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Prioritizing orbital debris for active debris removal missions2017In: IEEE Aerospace Conference Proceedings, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, 7943788Conference paper (Refereed)
    Abstract [en]

    This paper introduces a method of prioritizing orbital debris for future active debris removal missions, based on the evaluation of the total collision probability of each cataloged debris. The United States Space Surveillance Network actively monitors, tracks, and catalogs space debris orbiting Earth. The catalog is updated routinely, and is available to the public in the form of two-line element data. The total collision probability of a debris is defined as the overall probability of the debris colliding with any other debris in a given time window. The proposed method uses the two-line element data pertaining to each debris in the catalog to project the future state of the debris, i.e., the classical orbital elements, at predefined time steps for a given time window. The effects of orbital perturbations are considered wherever applicable. The relative distances between all debris are estimated in each time step, and pairwise collision probabilities are calculated for any two debris objects in the catalog. To obtain the total collision probability for a debris, the pairwise collision probabilities pertaining to the debris are summed. Further, for every debris object the trend in the total collision probability as the time window progresses is quantified, and debris objects are ranked based on their chance of collision in the time window. The outcome of the study is compared with target debris proposed in other studies.

  • 49.
    Kereluk, Jason A.
    et al.
    University of Toronto, Institute for Aerospace Studies.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Task-based optimization of reconfigurable robot manipulators2017In: Advanced Robotics, ISSN 0169-1864, E-ISSN 1568-5535, Vol. 31, no 16, 836-850 p.Article in journal (Refereed)
    Abstract [en]

    Reconfigurable Manipulators are structurally redundant robots that utilize a subset of their joints to perform a specific task optimally. This paper presents a method of finding a task-based optimal configuration for a new type of reconfigurable robot manipulator, called the modular autonomously reconfigurable serial (MARS) manipulator. The reconfiguration optimization treats the joint space of the MARS manipulator as a 12-dimensional smooth configuration manifold. The manifold is discretized and ranked based on a variety of criteria, and then clustered into attractive and repellent regions. The user then specifies which regions are desired in the target configuration, and the manifold is reduced in dimension in order to maximize the number of attractive regions and minimize the number of repellent regions. Six manipulator configurations are synthesized using this approach, and their effectiveness is compared.

  • 50.
    Kereluk, Jason Alexander
    et al.
    Space Mechatronics Group, Institute for Aerospace Studies, University of Toronto.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    A New Modular, Autonomously Reconfigurable Manipulator Platform2015In: International Journal of Advanced Robotic Systems, ISSN 1729-8806, E-ISSN 1729-8814, Vol. 12, 71Article in journal (Refereed)
    Abstract [en]

    This paper discusses the design and development of a new Modular, Autonomously Reconfigurable Serial manipulator platform for advanced manufacturing, termed as the MARS manipulator. The platform consists of i) an 18-Degree-of-Freedom (DOF) serial-link manipulator capable of locking any of its joints at any position in their continuous range, such that it can emulate fewer-DOF serial manipulators with different kinematic and dynamic parameters, and ii) an integrated simulation and design environment that provides control over the manipulator hardware as well as a toolset for the design, implementation and optimization of a desired manipulator configuration for a given task. The effectiveness of the MARS manipulator to adapt its configuration to various tasks is examined by assuming two well-known configurations, SCARA and articulated, and by performing a specific task with each of them. The variation in effectiveness of the two configurations in terms of the end-effector trajectory, end-effector accuracy and power consumption is discussed. Further, these configurations are optimized with respect to their performance accuracy, and compared to their pre-optimized versions. Finally, the accuracy model of the simulation is compared against the physical hardware system, running the same task.

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