A Hardware Test-Bed (HTB) is developed to serve as a platform for power grid emulation. For maximum flexibility, power converters, which can accommodate various control algorithms and behave distinctively based on the...
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ISBN:
(纸本)9781479957774
A Hardware Test-Bed (HTB) is developed to serve as a platform for power grid emulation. For maximum flexibility, power converters, which can accommodate various control algorithms and behave distinctively based on the applied model and control, is adopted. With the developed emulators, such as generator, load, wind turbine, and PV emulators, diverse research and experiments can be performed by using the HTB. This paper introduces the emulating method, hardware, control and communication structure of the HTB. At the same time, experimental results are compared with simulation to verify the emulation.
The primary concern of the present paper is the regulation of an uncertain wave process with collocated boundary sensing and Neumann-type actuation. It exhibits an unknown constant elasticity parameter and it is affec...
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ISBN:
(纸本)9781467357159
The primary concern of the present paper is the regulation of an uncertain wave process with collocated boundary sensing and Neumann-type actuation. It exhibits an unknown constant elasticity parameter and it is affected by a boundary disturbance, which is bounded in magnitude. The proposed robust synthesis is formed by the combination between linear PD-type control action and the Twisting second order sliding mode control algorithm. It is applied here to achieve the global asymptotic stabilization of an infinite dimensional system in a suitable Sobolev space. The proposed boundary control algorithm is also applied to design an observer for a wave PDE of the same type as that dealt with in the boundary controller design. The effectiveness of the developed controller scheme is supported by simulation results.
This paper proposes a decentralized secondary control for islanded microgrids based on consensus algorithms. In a microgrid, the secondary control is implemented in order to eliminate the frequency changes caused by t...
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ISBN:
(纸本)9781479957774
This paper proposes a decentralized secondary control for islanded microgrids based on consensus algorithms. In a microgrid, the secondary control is implemented in order to eliminate the frequency changes caused by the primary control when coordinating renewable energy sources and energy storage systems. Nevertheless, the conventional decentralized secondary control, although does not need to be implemented in a microgrid central controller (MGCC), it has the limitation that all decentralized controllers must be mutually synchronized. In a clear cut contrast, the proposed secondary control requires only a more simplified communication protocol and a sparse communication network. Moreover, the proposed approach based on dynamic consensus algorithms is able to achieve the coordinated secondary performance even when all units are initially out-of-synchronism. The control algorithm implemented in an islanded microgrid system is tested in different scenarios by means of hardware-in-the-loop results.
The focus of this paper is distributed control of multiagent systems in a-priori given, user-defined finite-time interval using a recently developed time transformation approach. In particular, we utilize a time trans...
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ISBN:
(纸本)9781538679012;9781538679265
The focus of this paper is distributed control of multiagent systems in a-priori given, user-defined finite-time interval using a recently developed time transformation approach. In particular, we utilize a time transformation function to convert a user-defined finite-time interval to a stretched infinite-time interval such that a distributed control algorithm can be designed on this stretched interval and then it can be transformed back to the original finite-time interval in order to satisfy a given multiagent system objective. In addition, the robustness of the resulting finite-time distributed control algorithm against vanishing and non-vanishing system uncertainties is also discussed. In contrast to existing finite-time approaches, the presented algorithm can preserve apriori given, user-defined finite-time convergence regardless of the initial conditions of the multiagent system and without the need for a knowledge of the upper bounds of the considered system uncertainty classes.
Model-free approaches such as Artificial Neural Networks and Fuzzy Controllers are widely used in the control of Antilock Braking System (ABS) due to its strongly nonlinear structure and uncertainties involved. In thi...
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ISBN:
(纸本)9781479902255
Model-free approaches such as Artificial Neural Networks and Fuzzy Controllers are widely used in the control of Antilock Braking System (ABS) due to its strongly nonlinear structure and uncertainties involved. In this paper the design of a Spiking Neural Network (SNN) controller is considered for the regulation of the wheel slip value at its optimum value. For the training of the network a gradient descent based approach is followed. To formulate the generation of a new spike train from the incoming spikes, the Spike Response Model (SRM) is used. Delay coding is utilized to convert real numbers into spike times. The control algorithm is applied to a quarter vehicle model, and it is verified through simulations indicating fast convergence and good performance of the designed controller.
Current off-the-shelf underwater gliders (UGs) are large, heavy, expensive, and difficult to modify, both in hardware and software, which limits their use for multivehicle coordination experiments and deployment in hi...
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ISBN:
(纸本)9781479901777
Current off-the-shelf underwater gliders (UGs) are large, heavy, expensive, and difficult to modify, both in hardware and software, which limits their use for multivehicle coordination experiments and deployment in high-risk environments. To address these challenges, the Nonlinear and Autonomous Systems Laboratory (NAS Lab) at Michigan Tech has designed two types of UGs for concept development, testing, and problem solving, and additionally, for scaffolding advanced interest and education in engineering. The first, a Glider for Underwater Presentation and Promoting Interest in Engineering (GUPPIE), nationally targets high school students and undergraduates to provide these students a UG platform for hands-on experience in concept development, testing, and problem solving. The second platform is a Glider for Autonomous Littoral Underwater Research (GALUR). At 10% of the cost of current models, the GALUR was designed to serve as a low cost multivehicle control testbed for disparate research groups who need to test and validate control algorithms. Still a highly-maneuverable UG, the GALUR allows researchers to address underwater communication issues by implementing control strategies for individual and multiple vehicle underwater data collection and mapping. Through the process of developing and testing these two UGs, the research team is ultimately working toward their long term goal of developing a fleet of low cost highly maneuverable underwater gliders. This paper details the challenges and milestones of the development process, and outlines the future research trajectory and goals.
A data-based policy for iterative control task is presented. The proposed strategy is model-free and can be applied whenever safe input and state trajectories of a system performing an iterative task are available. Th...
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ISBN:
(纸本)9781538679012;9781538679265
A data-based policy for iterative control task is presented. The proposed strategy is model-free and can be applied whenever safe input and state trajectories of a system performing an iterative task are available. These trajectories, together with a user-defined cost function, are exploited to construct a piecewise affine approximation to the value function. The approximated value function is then used to evaluate the control policy by solving a linear program. We show that for linear system subject to convex cost and constraints, the proposed strategy guarantees closed-loop constraint satisfaction and performance bounds for the closed-loop trajectory. We evaluate the proposed strategy in simulations and experiments, the latter carried out on the Berkeley Autonomous Race Car (BARC) platform. We show that the proposed strategy is able to reduce the computation time by one order of magnitude while achieving the same performance as our model-based control algorithm.
This work introduces a novel methodology to assist the evaluation of a wide class of control algorithms for all-type aircrafts using Hardware-in-the-Loop (HiL) based flight simulation. The originality of this paper is...
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ISBN:
(纸本)9781479916191
This work introduces a novel methodology to assist the evaluation of a wide class of control algorithms for all-type aircrafts using Hardware-in-the-Loop (HiL) based flight simulation. The originality of this paper is using Microsoft Flight Simulator (MSFS) as the environment to embed both dynamic and graphic models of Ascending Technologies Pelican MAV (Mini Aerial Vehicle) flying robot, and using an external embedded system to control the attitude of this virtual aircraft. The full duplex communication between the virtual aircraft and the control algorithm is achieved by a custom Delphi software named FVMS (Flight Variables Management System), presented in its first version in Aeroconf 2013, fully developed by Aerial Robots Team (ART). FVMS software is able to reach (read/write) a large number of flight variables from MSFS, send them to the external hardware and receive back the control signals to actuate in the virtual aircraft. We first completely present FVMS system architecture and main features. Later, the synthesis and the application of the optimal H-Infinity robust control algorithm in the external embedded system, connected to FMVS through USB interface at 115.200 bits/s of baud rate. The microcontroller used was the Microchip 16-bits dsPIC33FJ128MC706A, which assumes the complete attitude control of the virtual Pelican MAV robot. Regarding MAVs control evaluation, HiL simulation, considerably contributes to save battery time, to ease control synthesis and prototyping and to prevent accidents during tests with the real robot. The final goal is to evaluate the stability of the Pelican platform in hovering tasks in flight simulation focusing on the efficiency of the external hardware to properly deal with the optimal H-Infinity robust control algorithm actions. The HiL control of the MAV capabilities can be extended to assist the design of other classes of controllers. Such methodology allows designers to expedite control changes, e.g., gain modification in
Laser Metal Deposition (LMD) is a layer-based manufacturing process in which a laser and powdered metal are used to create a molten bead that is then traced along a path to create functional parts. The properties of t...
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ISBN:
(纸本)9781479901777
Laser Metal Deposition (LMD) is a layer-based manufacturing process in which a laser and powdered metal are used to create a molten bead that is then traced along a path to create functional parts. The properties of the structure, including shape and material microstructure, are the result of complex interactions between the laser, the powder, the part substrate and other factors. Thus, a control algorithm is needed to accurately produce the designed part. However, feedback control of the process can create phase lag in the resulting control structure, which in turn can create dimensional instability. Additionally, the LMD process has been shown to change with part height or layer number. Taking these issues into account, a feed-forward, adaptive-type controller that changes with each fabricated layer, should be used. This paper first presents a dynamic model for the LMD process that incorporates the dependency of the process on part height. Then, an optimal Iterative Learning Process Control algorithm is presented to regulate the melt pool morphology of a deposited part using layer number as the iteration axis. A simulation study on the LMD process using the designed process controller shows that it is able to achieve good tracking performance.
This paper presents a disturbance observer for the sigma.7 haptic device. External torques on the haptic device links are observed to distinguish between intended user interaction and accidental collisions of the link...
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ISBN:
(纸本)9781467363563
This paper presents a disturbance observer for the sigma.7 haptic device. External torques on the haptic device links are observed to distinguish between intended user interaction and accidental collisions of the links. Collisions can be unintentional contact of the human operator, e.g. with his knee, other people accidentally getting in contact with the haptic device or objects falling on it. The observer is based on the dynamic model of the device and sensor measurements from the joint's position sensors and an integrated force/torque sensor. Is is implemented concurrently with a control algorithm that uses the force/torque sensor to effectively reduce the inertia and friction of the sigma.7. Furthermore, forces and torques applied on the grasping unit by the human operator are observed. Experiments are done with the sigma.7 customized for the German Aerospace Center (DLR) by Force Dimension.
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