| 1. |
- Alepuz, Javier Pérez, et al.
(författare)
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Direct image-based visual servoing of free-floating space manipulators
- 2016
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Ingår i: Aerospace Science and Technology. - : Elsevier BV. - 1270-9638 .- 1626-3219. ; 55, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Anthony, Niklas, et al.
(författare)
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Asteroid engineering : The state-of-the-art of Near-Earth Asteroids science and technology
- 2018
-
Ingår i: Progress in Aerospace Sciences. - : Elsevier. - 0376-0421 .- 1873-1724. ; 100, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a comprehensive review of the science and technology of accessing near-Earth asteroids (NEAs), or making them accessible, for obtaining both information and resources. The survey is divided into four major groups of NEA study, namely a) discovery (population estimation and detection), b) Exploration (identification and characterization), c) deflection and redirection, and d) mining (prospecting, excavation, processing, refining, storage.). Recent research and development advancements from both industry and academia are discussed in each group, and certain specific future directions are highlighted. Some concluding remarks are made at the end, including the need for creating new educational programs to train competent engineers and researchers for the taskforce in the new field of asteroid engineering in near future
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| 3. |
- Anthony, Niklas, et al.
(författare)
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Cubesat Minimoon Rendezvous Mission Synthesis and Analysis
- 2018
-
Ingår i: IAC-18. - : International Astronautical Federation.
-
Konferensbidrag (refereegranskat)abstract
- This paper introduces a mission concept for the remote characterization of a temporarily-captured asteroid, or “minimoon”, based on the utilization of the CubeSat form-factor. Minimoons are a subpopulation of the estimated two million Near-Earth Objects (NEOs) under 2 meters in diameter, which pass within the Moon’s orbit every year. These temporarily-captured objects do not remain in the Earth-Moon system for long, typically less than one year, and are thus a challenge for developing conventional spacecraft missions. A potential solution to this problem is to utilize the typical rapid-development timelines that CubeSat missions possess. This paper will analyze the requirements and limitations in developing a mission for a CubeSat to rendezvous or fly by a minimoon. This includes exploring the capabilities and applicability of the CubeSat technologies for such a mission, analyzing the erratic nature of minimoon orbits, lying out how such a mission project would be managed, and finally presenting a case study of such missions on the only known minimoon so far, Asteroid 2006 RH120.
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| 4. |
- Bazzocchi, Michael C. F., et al.
(författare)
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A Systematic Assessment of Asteroid Redirection Methods for Resource Exploitation
- 2015
-
Konferensbidrag (refereegranskat)abstract
- This paper provides a systematic comparison of the primary asteroid redirection techniques from the perspective of resource exploitation. The goal is to examine the methods for the redirection of a near-Earth asteroid to a stable and easily accessible orbit in the Earth-moon system in order to exploit asteroid resources. The context of resource exploitation provides clear constraints on the asteroid redirection mission, and a systematic comparison can be established within this scope. This work describes each redirection method, and considers the major criteria for mission design. Moreover, a Monte Carlo analysis is performed to assess some attributes concerning the uncertainty intrinsic to asteroid redirection missions. The attributes for each redirection method are then aggregated using a multi-criteria decision making approach. Lastly, the results of the aggregation are presented and discussed.
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| 5. |
- Bazzocchi, Michael C. F., et al.
(författare)
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An Assessment of Multiple Spacecraft Formation for Asteroid Redirection
- 2016
-
Ingår i: Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan. - Tokyo : Japan Society for Aeronautical and Space Sciences. - 1884-0485. ; 14:ists30, s. Pk_137-Pk_146
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Bazzocchi, Michael C. F., et al.
(författare)
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Application of asteroid redirection methods to orbital debris removal
- 2016
-
Ingår i: 2016 IEEE Aerospace Conference. - Piscataway, NJ : IEEE Communications Society. - 9781467376761
-
Konferensbidrag (refereegranskat)abstract
- 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
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| 7. |
- Bazzocchi, Michael C. F., et al.
(författare)
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Application of pseudo-equinoctial shaping to Near-Earth asteroid orbital transfer
- 2017
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Ingår i: IEEE Aerospace Conference Proceedings. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509016136
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 8. |
- Bazzocchi, Michael C. F., et al.
(författare)
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Asteroid detumbling for redirection missions
- 2018
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Ingår i: 2018 IEEE Aerospace Conference. - : IEEE Computer Society. - 9781538620144
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Konferensbidrag (refereegranskat)abstract
- In order to accomplish most asteroid redirection missions, rotational control of the asteroid body is required. Small near-Earth asteroids tend to exhibit a significant range of rotational and tumbling properties. This work provides an analysis of asteroid detumbling using a formation of spacecraft. Through an orbiter and three landed thruster spacecraft, a low-thrust detumbling maneuver is performed on two illustrative asteroids. The asteroid scenarios are designed such that they reflect the characteristics of possible redirection scenarios. In particular the geometries, densities, angular velocities, and masses of the asteroids are adjusted according to available asteroid data to provide two unique redirection scenarios. The asteroid and spacecraft specifications are outlined, as well as the formulations for the detumbling maneuver. The results of the maneuver are discussed along with the key detumbling parameters and timeframe required.
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| 9. |
- Bazzocchi, Michael C. F., et al.
(författare)
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Asteroid Redirection Mission Evaluation Using Multiple Landers
- 2018
-
Ingår i: The Journal of the astronautical sciences. - : Springer. - 0021-9142 .- 2195-0571. ; 65:2, s. 183-204
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, a low-thrust tugboat redirection method is assessed using multiple spacecraft for a target range of small near-Earth asteroids. The benefits of a landed configuration of tugboat spacecraft in formation are examined for the redirection of a near-Earth asteroid. The tugboat method uses a gimballed thruster with a highly collimated ion beam to generate a thrust on the asteroid. The target asteroid range focuses on near-Earth asteroids smaller than 150 m in diameter, and carbonaceous (C-type) asteroids, due to the volatiles available for in-situ utilization. The assessment focuses primarily on the three key parameters, i.e., the asteroid mass redirected, the timeframe for redirection, and the overall system cost. An evaluation methodology for each parameter is discussed in detail, and the parameters are employed to determine the expected return and feasibility of the redirection mission. The number of spacecraft employed is optimized along with the electrical power needed for each spacecraft to ensure the highest possible return on investment. A discussion of the optimization results and the benefits of spacecraft formation for the tugboat method are presented.
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| 10. |
- Bazzocchi, Michael C.F., et al.
(författare)
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Comparative analysis of redirection methods for asteroid resource exploitation
- 2016
-
Ingår i: Acta Astronautica. - : Elsevier BV. - 0094-5765 .- 1879-2030. ; 120, s. 1-19
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 11. |
- Bazzocchi, Michael C. F., et al.
(författare)
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Concurrent Redirection and Attitude Control of an Asteroid
- 2019
-
Ingår i: 2019 IEEE Aerospace Conference. - : IEEE.
-
Konferensbidrag (refereegranskat)abstract
- This paper demonstrates the applicability of two low-thrust spacecraft for the task of concurrently redirecting an asteroid and controlling its attitude. Through the use of available observational data, a synthetic near-Earth asteroid, with suitable characteristics for a resource utilization mission, is designed. The asteroid is given an initial orientation and angular velocity, such that it is in a tumbling state. The two spacecraft are attached to the asteroid surface, and employ low-thrust ion thrusters for the attitude control and redirection of the asteroid. The spacecraft first detumble the asteroid body using their torque-inducing thrusters, and then re-orient the asteroid such that the redirection thrusters are aligned with the redirection thrust vector. The spacecraft then ensure the asteroid's orientation is aligned with the redirection thrust vector throughout the entire trajectory transfer maneuver, while ensuring the angular velocity remains bounded around zero. The trajectory design is a low-thrust maneuver, based on Gauss' variational equations, which redirects the asteroid from its orbit about the Sun to rendezvous with Earth. A linear control law is employed for both the detumbling and redirection maneuver with attitude control. The overall performance of the system and the applicability of the approach are discussed.
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| 12. |
- Bazzocchi, Michael C. F., et al.
(författare)
-
Formation of Multiple Landers for Asteroid Detumbling
- 2018
-
Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177 .- 1879-1948. ; 62:3, s. 732-744
-
Tidskriftsartikel (refereegranskat)abstract
- This work develops a method for ascertaining the landing locations and thruster orientations of a formation of multiple spacecraft on an irregular asteroid for discrete time optimal detumbling control, as a prerequisite to asteroid redirection. Asteroid geometries are known to be extremely irregular, especially for small asteroids, which are the typical targets for redirection missions. The method entails the modelling of asteroids as convex polyhedra with triangular facets, and computing the mass and inertial properties through the divergence theorem and Green’s theorem. Given the asteroid geometry, mass, and inertial properties, the feasible lander locations and thruster orientations are determined. The model ensures full attitude control of the asteroid, using multiple spacecraft with fixed-orientation, low-thrust modules, through measures imposed on the location and orientation of each thruster. A linear control scheme is employed to assess the time and fuel requirements of the asteroid detumbling maneuver, given feasible spacecraft formation configurations and thruster orientations. The method then assesses the detumbling time performance of each formation configuration to determine the discrete optimal landed formation configuration for a given asteroid. Simulations are performed to demonstrate the method using an irregular asteroid with characteristics derived from available asteroid data. Extensions of the method are further discussed in light of the results.
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| 13. |
- Bazzocchi, Michael C. F., et al.
(författare)
-
Low-thrust orbit transfer of Arjuna-type asteroids
- 2016
-
Ingår i: AIAA/AAS Astrodynamics Specialist Conference, 2016. - Reston, Virginia : American Institute of Aeronautics and Astronautics. - 9781624104459
-
Konferensbidrag (refereegranskat)abstract
- 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
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| 14. |
- Bazzocchi, Michael C.F., et al.
(författare)
-
Stochastic optimization of asteroid three-dimensional trajectory transfer
- 2018
-
Ingår i: Acta Astronautica. - : Elsevier. - 0094-5765 .- 1879-2030. ; 152, s. 705-718
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, an approach to designing near-optimal nonplanar transfer trajectories for asteroids is introduced, taking into account the uncertainty in asteroid parameters. The approach is demonstrated using a specific known Near-Earth Asteroid (NEA) as a model for the transfer scenario. The designed trajectory redirects the NEA from its current orbit about the Sun to a new orbit in the Earth-Moon system. The approach utilizes a low-thrust redirection method, namely the ion beam method, to execute the transfer; however, the work can be extrapolated to most low-thrust redirection methods. Asteroid parameters, such as absolute magnitude, albedo and density, are modelled, and a Monte Carlo analysis is employed to investigate the redirection maneuver in light of the expected variation in parameters. The trajectory transfer is modelled in three dimensions through the use of pseudo-equinoctial shaping, and is subsequently optimized. Due to the large design space created by the 21 decision variables, the optimization is parsed into two main steps; first, a global optimization that employs a genetic algorithm, followed by a local optimization that utilizes sequential quadratic programming to refine the result from the global optimization. Lastly, the results of the Monte Carlo analysis for the near-optimal trajectory transfer of the NEA are discussed.
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| 15. |
- Bazzocchi, Michael C. F., et al.
(författare)
-
Study of Arjuna-Type Asteroids for Low-Thrust Orbital Transfer
- 2018
-
Ingår i: Journal of Spacecraft and Rockets. - : American Institute of Aeronautics and Astronautics. - 0022-4650 .- 1533-6794. ; 55:1, s. 37-48
-
Tidskriftsartikel (refereegranskat)abstract
- 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 a specific range of semimajor 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 uses 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 regard to key mission parameters, namely, time frame for redirection, number of orbital revolutions, system mass, propellant mass, thrust, power, system cost, and financial return rate
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| 16. |
- Bohra, Murtaza M., et al.
(författare)
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CPG-based online trajectory generation for quadruped rovers
- 2016
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Ingår i: 2015 IEEE International Conference on Robotics and Biomimetics (ROBIO). - Piscataway, NJ : IEEE Communications Society. - 9781467396745 ; , s. 1053-1058
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Konferensbidrag (refereegranskat)abstract
- 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
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| 17. |
- Browne Mwakyanjala, Moses, et al.
(författare)
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Concurrent development and verification of an all‐software baseband for satellite ground operations
- 2020
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Ingår i: International Journal of Satellite Communications And Networking. - : John Wiley & Sons. - 1542-0973 .- 1542-0981. ; 38:2, s. 209-227
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Tidskriftsartikel (refereegranskat)abstract
- Communication systems are adopting all‐software architectures, because of their scalability, extensibility, flexibility, and cost‐effectiveness. This paper introduces a concurrent approach to the development and verification of baseband systems for satellite ground operations based on the behaviour‐driven development methodology. The open‐source GNU Radio development kit is used for developing the software‐defined radio baseband signal processing, as well as simulating the satellite and realistic channel impairments. The system performance at the end shows deviations of less than 1 dB with respect to the ideal performance and the Green Book standards specified by the Consultative Committee for Space Data Systems.
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| 18. |
- Browne Mwakyanjala, Moses, et al.
(författare)
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Functional Analysis of Software-Defined Radio Baseband for Satellite Ground Operations
- 2019
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Ingår i: Journal of Spacecraft and Rockets. - : American Institute of Aeronautics and Astronautics. - 0022-4650 .- 1533-6794. ; 56:2, s. 458-475
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents functional analysis and system specifications of a baseband system using software-defined radio (SDR) technology. The analysis is primarily based on the latest blue-book standards from the Consultative Committee for Space Data Systems (CCSDS). It covers telemetry, telecommand, and ranging, as well as some specifications of the associated physical layers. The SDR-based baseband system is envisioned to support ground operations in the form of a software-as-a-Service (SaaS) private cloud.
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| 19. |
- Browne Mwakyanjala, Moses, et al.
(författare)
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Software-defined radio transceiver for QB50 CubeSat telemetry and telecommand
- 2016
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Ingår i: Proceedings of the 34th AIAA International Communications Satellite Systems Conference (ICSSC 2016). - Reston, Virginia : American Institute of Aeronautics and Astronautics.
-
Konferensbidrag (refereegranskat)abstract
- 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
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| 20. |
- Browne Mwakyanjala, Moses, et al.
(författare)
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Verification of phase and frequency modulation for software-defined radio baseband systems using field data
- 2017
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Ingår i: 35th AIAA International Communications Satellite Systems Conference, ICSSC 2017. - Reston, Virginia : American Institute of Aeronautics and Astronautics.
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the verification of phase and frequency modulation schemes for a software-defined radio baseband system that is being prototyped to support satellite telemetry, telecommand and ranging. It presents the theory behind the two modulation schemes, implementation and verification against emulated signals from a space-qualified hardware-based baseband system as well as from the Odin satellite.
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| 21. |
- Chhabra, Robin, et al.
(författare)
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A generalized exponential formula for forward and differential kinematics of open-chain multi-body systems
- 2014
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Ingår i: Mechanism and machine theory. - : Elsevier BV. - 0094-114X .- 1873-3999. ; 73, s. 61-75
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 22. |
- Chhabra, Robin, et al.
(författare)
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A holistic approach to concurrent engineering and its application to robotics
- 2014
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Ingår i: Concurrent Engineering - Research and Applications. - 1063-293X .- 1531-2003. ; 22:1, s. 48-61
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 23. |
- Chhabra, Robin, et al.
(författare)
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A holistic concurrent design approach to robotics using hardware-in-the-loop simulation
- 2013
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Ingår i: Mechatronics (Oxford). - : Elsevier BV. - 0957-4158 .- 1873-4006. ; 23:3, s. 335-345
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 24. |
- Chhabra, Robin, et al.
(författare)
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A linguistic approach to concurrent design
- 2015
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Ingår i: Journal of Intelligent & Fuzzy Systems. - 1064-1246 .- 1875-8967. ; 28:5, s. 1985-2001
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 25. |
- Chhabra, Robin, et al.
(författare)
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A Unified Approach to Input-output Linearization and Concurrent Control of Underactuated Open-chain Multi-body Systems with Holonomic and Nonholonomic Constraints
- 2016
-
Ingår i: Journal of dynamical and control systems. - : Springer Science and Business Media LLC. - 1079-2724 .- 1573-8698. ; 22:1, s. 129-168
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 26. |
- Chhabra, Robin, et al.
(författare)
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Concurrent synthesis of robot manipulators using hardware-in-the-loop simulation
- 2009
-
Ingår i: IEEE International Conference on Robotics and Automation, ICRA, Kobe, Japan, 12-17 May 2009. - Piscataway, NJ : IEEE Communications Society. - 9781424427895 ; , s. 568-573
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 27. |
- Chhabra, Robin, et al.
(författare)
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Holistic system modeling in mechatronics
- 2011
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Ingår i: Mechatronics (Oxford). - : Elsevier BV. - 0957-4158 .- 1873-4006. ; 21:1, s. 166-175
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 28. |
- Chhabra, Robin, et al.
(författare)
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Linguistic mechatronics
- 2008
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Ingår i: IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM, Xi'an, China, 2-5 July 2008. - Piscataway, NJ : IEEE Communications Society. - 9781424424955 ; , s. 1315-1320
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 29. |
- Chhabra, Robin, et al.
(författare)
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Nonholonomic dynamical reduction of open-chain multi-body systems : A geometric approach
- 2014
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Ingår i: Mechanism and machine theory. - : Elsevier BV. - 0094-114X .- 1873-3999. ; 82, s. 231-255
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 30. |
- Chhabra, Robin, et al.
(författare)
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Reduction of Hamiltonian Mechanical Systems With Affine Constraints : A Geometric Unification
- 2017
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Ingår i: Journal of Computational and Nonlinear Dynamics. - : The American Society of Mechanical Engineers (ASME). - 1555-1415 .- 1555-1423. ; 12:2
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 31. |
- Chhabra, Robin, et al.
(författare)
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Symplectic reduction of holonomic open-chain multi-body systems with constant momentum
- 2015
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Ingår i: Journal of Geometry and Physics. - : Elsevier BV. - 0393-0440 .- 1879-1662. ; 89, s. 82-110
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 32. |
- Daniluk, S., et al.
(författare)
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An advice mechanism for heterogeneous robot teams
- 2020
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Ingår i: International Journal of Robotics and Automation. - : ACTA Press. - 0826-8185 .- 1925-7090. ; 35:1, s. 53-68
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an advice mechanism compatible with heterogeneous advisers that incorporates advice into the advisee's policy via a method guaranteeing convergence to an optimal policy. Further, the mechanism has the capability to use multiple advisers at each time step and decide when advice should be requested and accepted, such that the use of advice decreases over time. Experiments are formed with a simulated team of heterogeneous robots performing a foraging task. We show that the proposed mechanism can provide a performance improvement for homogeneous and heterogeneous robot teams, and the use of advice decreases over time.
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| 33. |
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| 34. |
- Emami Khoonsari, Payam, et al.
(författare)
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Interoperable and scalable data analysis with microservices : Applications in metabolomics
- 2019
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Ingår i: Bioinformatics. - : Oxford University Press (OUP). - 1367-4803 .- 1367-4811. ; 35:19, s. 3752-3760
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Tidskriftsartikel (refereegranskat)abstract
- MotivationDeveloping a robust and performant data analysis workflow that integrates all necessary components whilst still being able to scale over multiple compute nodes is a challenging task. We introduce a generic method based on the microservice architecture, where software tools are encapsulated as Docker containers that can be connected into scientific workflows and executed using the Kubernetes container orchestrator.ResultsWe developed a Virtual Research Environment (VRE) which facilitates rapid integration of new tools and developing scalable and interoperable workflows for performing metabolomics data analysis. The environment can be launched on-demand on cloud resources and desktop computers. IT-expertise requirements on the user side are kept to a minimum, and workflows can be re-used effortlessly by any novice user. We validate our method in the field of metabolomics on two mass spectrometry, one nuclear magnetic resonance spectroscopy and one fluxomics study. We showed that the method scales dynamically with increasing availability of computational resources. We demonstrated that the method facilitates interoperability using integration of the major software suites resulting in a turn-key workflow encompassing all steps for mass-spectrometry-based metabolomics including preprocessing, statistics and identification. Microservices is a generic methodology that can serve any scientific discipline and opens up for new types of large-scale integrative science.
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| 35. |
- Emami, M. Reza, et al.
(författare)
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An outline of eDesign
- 2010
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Ingår i: ASEE Annual Conference and Exposition, Louisville, USA, 20-23 June 2010.
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 36. |
- Emami, Reza, et al.
(författare)
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A modular and turn-key remote-access hardware-in-the-loop platform for testing electric motors
- 2014
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Ingår i: Journal of Advanced Mechanical Design, Systems, and Manufacturing. - : Japan Society of Mechanical Engineers. - 1881-3054. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 37. |
- Emami, Reza, et al.
(författare)
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A remotely-accessible reconfigurable platform for robotics education
- 2013
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Ingår i: ASEE Annual Conference and Exposition, Atlanta, USA, 23-26 June 2013.
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 38. |
- Emami, Reza, et al.
(författare)
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A robust model-based fuzzy-logic controller for robot manipulators
- 1998
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Ingår i: 1998 IEEE International Conference on Robotics and Automation, Leuven, Belgium, 16-20 May 1998. - Piscataway, NJ : IEEE Communications Society. ; , s. 2500-2505
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 39. |
- Emami, Reza
(författare)
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Application of learning models to the engineering design pedagogy
- 2009
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Ingår i: ASEE Annual Conference and Exposition, Austin, USA, 14-17 June 2009.
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 40. |
- Emami, Reza, et al.
(författare)
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Concurrent Engineering of Robot Manipulators
- 2010
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Ingår i: Robot Manipulators New Achievements. - Wien : I-Tech Education and Publishing KG. - 9789533070902 ; , s. 211-240
-
Bokkapitel (refereegranskat)
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| 41. |
- Emami, Reza, et al.
(författare)
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Development of a systematic methodology of fuzzy logic modeling
- 1998
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Ingår i: IEEE transactions on fuzzy systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1063-6706 .- 1941-0034. ; 6:3, s. 346-361
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposs a systematic methodology of fuzzy logic modeling as a generic tool for modeling of complex systems. The methodology conveys three distinct features: 1) a unified parameterized reasoning formulation; 2) an improved fuzzy clustering algorithm; and 3) an efficient strategy of selecting significant system inputs and their membership functions. The reasoning mechanism introduces four parameters whose variation provides a continuous range of inference operation. As a result, we are no longer restricted to standard extremes in any step of reasoning. Unlike traditional approach of selecting the inference mechanism a priori, the fuzzy model itself can then adjust the reasoning process by optimizing the inference parameters based on input-output data. The fuzzy rules are generated through fuzzy c-means (FCM) clustering algorithm. Major bottle-necks of the algorithm are addressed and analytical solutions are suggested. Furthermore, we also address the classification process in fuzzy modelng to extend the derived fuzzy partition to the entire output space. This issue remains unattained in the current literature. In order to select suitable input variables among a finite number of candidates (unlike traditional approaches) we suggest a new strategy through which dominant input parameters are assigned in one step and no iteration process is required. Furthermore, a clustering technique called fuzzy line clustering is introduced to assign the input membership functions. In order to evaluate the proposed methodology, two examples - a nonlinear function and a gas furnace dynamic procedure - are investigated in detail. The significant improvement of the model is concluded compared to other fuzzy modeling approaches. © 1998 IEEE.
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| 42. |
- Emami, Reza, et al.
(författare)
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Engineering design pedagogy : a performance analysis
- 2020
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Ingår i: International journal of technology and design education. - : Springer. - 0957-7572 .- 1573-1804. ; 30:3, s. 553-585
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Tidskriftsartikel (refereegranskat)abstract
- Cornerstone design courses have become a major part of engineering curricula, where students with different personality types and learning styles work together to design, develop, build, and demonstrate the functionality of a prototype within the duration of a term. This study analyzes student and team performance against gender, personality types, and learning styles in a second-year engineering design course. Further, the correlations between several assessment mechanisms are studied, and the effects of three different instructional design approaches on students’ performance are explored. Data have been collected on student performance and psychometrics, including marks, gender, personality type, and learning style from 2001 to 2018. To identify students’ personality types and learning styles, Myers–Briggs Type Indicators (MBTI) and Neil Fleming’s Learning VARK tests were administered. To evaluate students’ performance in the course, a number of assessment mechanisms have been defined. Several statistical methods are used to analyze data, and to determine correlation between datasets. Over nearly two decades of marks, gender, MBTI, and VARK data for 2637 students are presented for an engineering design course. The results demonstrated that there was no significant difference in performance across most assessments based on gender or gender distribution on a team. A better performance was observed from VK bimodal and quadmodal learning styles in most assessment mechanisms. Further, certain MBTI groups, namely, judging types outperformed their peers in engineering design assessments, with interesting interplay between MBTI dimensions for specific assessments and team dynamics. Traditional assessment mechanisms, such as engineering notebook and design proposals, are shown to be good predictors of student success. Lastly, scaffolded design activities and front-loading of lecture content were shown to be beneficial for student learning. There is negligible performance difference between female and male students in the engineering design course. Students whose preferred learning styles align with the assessment themes showed better performance in the course. The outcomes of this paper can be readily applied by instructors for design of assessment mechanisms, course materials, team formation, and instructional design.
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| 43. |
- Emami, Reza, et al.
(författare)
-
Fuzzy-logic dynamics modeling of robot manipulators
- 1998
-
Ingår i: 1998 IEEE International Conference on Robotics and Automation, Leuven, Belgium, 16-20 May 1998. - Piscataway, NJ : IEEE Communications Society. ; , s. 2512-2517
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 44. |
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| 45. |
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| 46. |
- Emami, Reza, et al.
(författare)
-
Quaternion-based attitude control design and hardware-in-the-loop simulation of suborbital modules with cold gas thrusters
- 2015
-
Ingår i: Journal of Aerospace Engineering. - : SAGE Publications. - 0893-1321 .- 1943-5525. ; 229:4, s. 717-735
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 47. |
- Emami, Reza, et al.
(författare)
-
System, method and computer program for autonomously emulating robot manipulators of continuously-varying configurations
- 2013
-
Patent (populärvet., debatt m.m.)abstract
- 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.
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| 48. |
- Emami, Reza, et al.
(författare)
-
System, method and computer program for remotely testing system components over a network
- 2010
-
Patent (populärvet., debatt m.m.)abstract
- 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.
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| 49. |
- Emami, Reza, et al.
(författare)
-
Systematic design and analysis of fuzzy-logic control and application to robotics : Part II. Control
- 2000
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Ingår i: Robotics and Autonomous Systems. - 0921-8890 .- 1872-793X. ; 33:2-3, s. 89-108
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 50. |
- Emami, Reza, et al.
(författare)
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Systematic design and analysis of fuzzy-logic control and application to robotics : Part 1. Modeling
- 2000
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Ingår i: Robotics and Autonomous Systems. - 0921-8890 .- 1872-793X. ; 33:2-3, s. 65-88
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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