5,596 research outputs found
Cooperative Adaptive Control for Cloud-Based Robotics
This paper studies collaboration through the cloud in the context of
cooperative adaptive control for robot manipulators. We first consider the case
of multiple robots manipulating a common object through synchronous centralized
update laws to identify unknown inertial parameters. Through this development,
we introduce a notion of Collective Sufficient Richness, wherein parameter
convergence can be enabled through teamwork in the group. The introduction of
this property and the analysis of stable adaptive controllers that benefit from
it constitute the main new contributions of this work. Building on this
original example, we then consider decentralized update laws, time-varying
network topologies, and the influence of communication delays on this process.
Perhaps surprisingly, these nonidealized networked conditions inherit the same
benefits of convergence being determined through collective effects for the
group. Simple simulations of a planar manipulator identifying an unknown load
are provided to illustrate the central idea and benefits of Collective
Sufficient Richness.Comment: ICRA 201
Improved Distributed Estimation Method for Environmental\ud time-variant Physical variables in Static Sensor Networks
In this paper, an improved distributed estimation scheme for static sensor networks is developed. The scheme is developed for environmental time-variant physical variables. The main contribution of this work is that the algorithm in [1]-[3] has been extended, and a filter has been designed with weights, such that the variance of the estimation errors is minimized, thereby improving the filter design considerably\ud
and characterizing the performance limit of the filter, and thereby tracking a time-varying signal. Moreover, certain parameter optimization is alleviated with the application of a particular finite impulse response (FIR) filter. Simulation results are showing the effectiveness of the developed estimation algorithm
Event-triggering architectures for adaptive control of uncertain dynamical systems
In this dissertation, new approaches are presented for the design and implementation of networked adaptive control systems to reduce the wireless network utilization while guaranteeing system stability in the presence of system uncertainties. Specifically, the design and analysis of state feedback adaptive control systems over wireless networks using event-triggering control theory is first presented. The state feedback adaptive control results are then generalized to the output feedback case for dynamical systems with unmeasurable state vectors. This event-triggering approach is then adopted for large-scale uncertain dynamical systems. In particular, decentralized and distributed adaptive control methodologies are proposed with reduced wireless network utilization with stability guarantees.
In addition, for systems in the absence of uncertainties, a new observer-free output feedback cooperative control architecture is developed. Specifically, the proposed architecture is predicated on a nonminimal state-space realization that generates an expanded set of states only using the filtered input and filtered output and their derivatives for each vehicle, without the need for designing an observer for each vehicle. Building on the results of this new observer-free output feedback cooperative control architecture, an event-triggering methodology is next proposed for the output feedback cooperative control to schedule the exchanged output measurements information between the agents in order to reduce wireless network utilization. Finally, the output feedback cooperative control architecture is generalized to adaptive control for handling exogenous disturbances in the follower vehicles.
For each methodology, the closed-loop system stability properties are rigorously analyzed, the effect of the user-defined event-triggering thresholds and the controller design parameters on the overall system performance are characterized, and Zeno behavior is shown not to occur with the proposed algorithms --Abstract, page iv
CoMIX: A Multi-agent Reinforcement Learning Training Architecture for Efficient Decentralized Coordination and Independent Decision Making
Robust coordination skills enable agents to operate cohesively in shared
environments, together towards a common goal and, ideally, individually without
hindering each other's progress. To this end, this paper presents Coordinated
QMIX (CoMIX), a novel training framework for decentralized agents that enables
emergent coordination through flexible policies, allowing at the same time
independent decision-making at individual level. CoMIX models selfish and
collaborative behavior as incremental steps in each agent's decision process.
This allows agents to dynamically adapt their behavior to different situations
balancing independence and collaboration. Experiments using a variety of
simulation environments demonstrate that CoMIX outperforms baselines on
collaborative tasks. The results validate our incremental policy approach as
effective technique for improving coordination in multi-agent systems
Stability Boundaries for Offshore Wind Park Distributed Voltage Control
In order to identify mechanisms causing slow reactive power oscillations observed in an existing offshore wind power plant, and be able to avoid similar events in the future, voltage control is studied in this paper for a plant with a static synchronous compensator, type-4 wind turbines and a park pilot control. Using data from the actual wind power plant, all stabilizing subsystem voltage proportional-integral controller parameters are first characterized based on their Hurwitz signature. Inner loop current control is then designed using Internal Mode Control principles, and guidelines for feed forward filter design are given to obtain required disturbance rejection properties. The paper contributes by providing analytical relations between power plant control, droop, sampling time, electrical parameters and voltage control characteristics, and by assessing frequencies and damping of reactive power modes over a realistic envelope of electrical impedances and control parameters
Advanced Islanded-Mode Control of Microgrids
This thesis is focused on modeling, control, stability, and power management of electronically-interfaced distributed energy resource (DER) units for microgrids. Voltage amplitude and frequency regulation in an islanded microgrid is one of the main control requirements. To that end, first a mathematical model is developed for an islanded DER system and then, based on the developed model, amplitude and frequency control schemes are proposed for (i) balanced and linear loads and (ii) unbalanced and nonlinear loads. The proposed control strategy for unbalanced and nonlinear loads, utilizes repetitive control scheme to reject the effects of unbalanced and/or distorted load currents. Moreover, a new approach is proposed to maintain the effectiveness of the repetitive control under variable-frequency operational scenarios. The thesis also presents an adaptive feedforward compensation strategy to enhance the stability and robustness of the droop-controlled microgrids to droop coefficients and network uncertainties. The proposed feedforward strategy preserves the steady-state characteristics that the conventional droop control strategy exhibits and, therefore, does not compromise the steady-state power shares of the DER systems or the voltage/frequency regulation of the microgrid. Finally, a unified control strategy is proposed to enable islanded and grid-connected operation of DER systems, with no need to detect the microgrid mode of operation or to switch between different controllers, simplifying the control of the host microgrid. The effectiveness of the proposed control strategies are demonstrated through time-domain simulation studies conducted in the PSCAD/EMTDC software environment
Regional Data Archiving and Management for Northeast Illinois
This project studies the feasibility and implementation options for establishing a regional data archiving system to help monitor
and manage traffic operations and planning for the northeastern Illinois region. It aims to provide a clear guidance to the
regional transportation agencies, from both technical and business perspectives, about building such a comprehensive
transportation information system. Several implementation alternatives are identified and analyzed. This research is carried
out in three phases.
In the first phase, existing documents related to ITS deployments in the broader Chicago area are summarized, and a
thorough review is conducted of similar systems across the country. Various stakeholders are interviewed to collect
information on all data elements that they store, including the format, system, and granularity. Their perception of a data
archive system, such as potential benefits and costs, is also surveyed. In the second phase, a conceptual design of the
database is developed. This conceptual design includes system architecture, functional modules, user interfaces, and
examples of usage. In the last phase, the possible business models for the archive system to sustain itself are reviewed. We
estimate initial capital and recurring operational/maintenance costs for the system based on realistic information on the
hardware, software, labor, and resource requirements. We also identify possible revenue opportunities.
A few implementation options for the archive system are summarized in this report; namely:
1. System hosted by a partnering agency
2. System contracted to a university
3. System contracted to a national laboratory
4. System outsourced to a service provider
The costs, advantages and disadvantages for each of these recommended options are also provided.ICT-R27-22published or submitted for publicationis peer reviewe
Sliding mode controller applied to coupled inductor dual boost inverter
A coupled inductor-dual boost-inverter (CIDBI) with differential structure has been presented to be applied to micro-inverter photovoltaic module system because of its turn ratio of high-voltage level. However, it is hard for CIDBI converter with conventional PI regulator to be designed stable and achieve good dynamic performance, given the fact that it is a high order system. In view of this situation, a sliding mode control (SMC) strategy is introduced in this paper, and two different sliding mode controllers (SMCs) are proposed and adopted in the left and right side of the two Boost sub-circuits respectively to implement corresponding regulation of voltage and current. The schemes of the SMCs have been elaborated in this paper including the establishment of the system variable structure model, the selection of the sliding surface, the determination of the control law, and the presentation of the reaching conditions and sliding domain. Finally, the mathematic analysis and the proposed SMC are verified by the experimental results
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