We present a path tracking algorithm for navigation of an oceanographic unmanned aeronautical vehicle. Aircraft bank angle is used to maintain desired closing speeds along and normal to the desired track. The algorith...
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ISBN:
(纸本)9781424406340;142440634X
We present a path tracking algorithm for navigation of an oceanographic unmanned aeronautical vehicle. Aircraft bank angle is used to maintain desired closing speeds along and normal to the desired track. The algorithm is capable of tracking linear and circular path segments. Simulated flights under near gale force winds suggest the algorithm is sufficiently robust for practical navigation during off-shore research. The algorithm's simplicity permits a high frequency update by the autopilot's low-power processor.
The safety control problem for the class of block-triangular order preserving hybrid automata with imperfect state information is addressed. A dynamic feedback law is proposed, which exploits the order preserving prop...
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ISBN:
(纸本)9781424414970;1424414970
The safety control problem for the class of block-triangular order preserving hybrid automata with imperfect state information is addressed. A dynamic feedback law is proposed, which exploits the order preserving properties of the dynamics to construct state estimation and control algorithms that have linear complexity in the number of variables. The proposed algorithms are applied to a collision avoidance problem arising in the context of intelligent transportation.
We consider finding a time-optimal trajectory for an airplane from some starting point and orientation to some final point and orientation. Our model extends the Dubins car [15] to have altitude, which leads to Dubins...
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ISBN:
(纸本)9781424414970;1424414970
We consider finding a time-optimal trajectory for an airplane from some starting point and orientation to some final point and orientation. Our model extends the Dubins car [15] to have altitude, which leads to Dubins airplane. We assume that the system has independent bounded control over the altitude velocity as well as the turning rate in the plane. Through the use of the Pontryagin Maximum Principle, we characterize the time-optimal trajectories for the system. They are composed of turns with minimum radius, straight line segments, and pieces of planar elastica. One motivation for determining these elementary pieces is for use as motion primitives in modern planning and control algorithms that consider obstacles.
In this paper, a switching control algorithm for the stabilization of network control systems (NCS) with time-varying delay in the presence of disturbance is investigated. Discrete-time equivalent model of NCS with ti...
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ISBN:
(纸本)9781424414970;1424414970
In this paper, a switching control algorithm for the stabilization of network control systems (NCS) with time-varying delay in the presence of disturbance is investigated. Discrete-time equivalent model of NCS with time delay and disturbance is derived. It is assumed that the time delay is unknown and time-varying, nonetheless bounded with a known bound. It is also assumed that the system is highly uncertain, and a set of controllers are given, which stabilize the whole uncertain parameter space. A switching scheme is developed subsequently to find the stabilizing controller at any time. A thorough stability analysis for NCS under the mentioned control scheme is provided. Simulation results are presented to show the efficacy of the proposed method in stabilization of an unstable NCS subject to time-varying delay and disturbance.
This paper addresses the problem of using a team of UAVs to cooperatively monitor multiple forest fires (called hotspots) in a region. We deploy two types of agents: service agents that locally monitor the state of th...
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ISBN:
(纸本)9781424414970;1424414970
This paper addresses the problem of using a team of UAVs to cooperatively monitor multiple forest fires (called hotspots) in a region. We deploy two types of agents: service agents that locally monitor the state of the hotspots and detector agents that search for hotspots and assign service agents to those that are detected. We develop an assignment scheme based on auctions to perform the assignment of a hotspot to a group of service agents. While monitoring a hotspot, service agents are required to be equally spaced around the perimeter. In order to achieve equal spacing around the hotspot perimeter, we develop a splay state controller that ensures the convergence of the service agents to the equally spaced configuration. We also address the problems associated with tracking hotspots that expand in size and possibly combine together. Simulation results are presented to validate the assignment and control algorithms.
We analyze the effects of time-delay in optical communication networks. A link level power control scheme adjusts the OSNR value of the signals toward channel OSNR optimization. We utilize the model from [4] along wit...
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ISBN:
(纸本)9781424414970;1424414970
We analyze the effects of time-delay in optical communication networks. A link level power control scheme adjusts the OSNR value of the signals toward channel OSNR optimization. We utilize the model from [4] along with its game-theoretic based control algorithm. We incorporate time-delay into the closed loop system, for the general case where every link has a unique time-delay. We derive sufficient conditions for stability under arbitrary time-delays and network configurations.
In this paper, we show that max-min fair congestion control methods with a stable symmetric Jacobian remain stable under arbitrary feedback delay and the stability condition of such methods does not involve any of the...
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ISBN:
(纸本)9781424414970;1424414970
In this paper, we show that max-min fair congestion control methods with a stable symmetric Jacobian remain stable under arbitrary feedback delay and the stability condition of such methods does not involve any of the delays. To demonstrate the practicality of the obtained result, we change the original algorithm in Kelly's work to become robust under random feedback delay and fixed constants of the control equation. The performance analysis shows that it offers smooth sending rate, exponential convergence to efficiency, and fast convergence to fairness, all of which make it be meaningful for future high-speed networks.
Commercially viable aerial robotic vehicles require low-cost attitude stabilisation systems that are robust to noise and sensor bias. A typical attitude stabilisation system consists of MEMs accelerometers, gyroscopes...
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ISBN:
(纸本)9781424414970;1424414970
Commercially viable aerial robotic vehicles require low-cost attitude stabilisation systems that are robust to noise and sensor bias. A typical attitude stabilisation system consists of MEMs accelerometers, gyroscopes linked to separate attitude estimator and attitude controller algorithms. This paper proposes a non-linear attitude stabiliser for low-cost aerial robotic vehicles that combines attitude and bias estimation with control. The attitude control algorithm is based on a non-linear control Lyapunov function analysis derived directly in terms of the rigid-body attitude dynamics and measurement signals.
This paper presents a new Digital Self-Oscillating Modulator (DiSOM) for DC/DC converters. The DiSOM modulator alllows the digital control algorithm to sample the output voltage at a sampling frequency higher than the...
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ISBN:
(纸本)9781424418718
This paper presents a new Digital Self-Oscillating Modulator (DiSOM) for DC/DC converters. The DiSOM modulator alllows the digital control algorithm to sample the output voltage at a sampling frequency higher than the converter switching frequency. This enables higher control loop bandwidth than for traditional digital PWM modulators given a certain switching frequency. A synchronised version of the DiSOM modulator is derived for interleaved converters. A prototype interleaved Buck converter for Point of Load applications has been designed and built to test the performance of DiSOM modulator. The DiSOM modulator and a digital control algorithm have been implemented in an FPGA. Experimental results show that the converter has a very fast transient response when a loadstep is applied to the output. For a loadstep of 50% of nominal output current the output voltage overshoot is less than 2.5% of the nominal output voltage and the settling time is just 8 switching periods.
In this letter, clonal selection algorithm (CSA) with singular value decomposition (SVD) method is investigated for the realization of two-dimentional (2D) infinite-impulse response (IIR) filters with arbitrary magnit...
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In this letter, clonal selection algorithm (CSA) with singular value decomposition (SVD) method is investigated for the realization of two-dimentional (2D) infinite-impulse response (IIR) filters with arbitrary magnitude responses. The CSA is applied to optimize the sampled frequencies of transition band of digital filters, then producing a planar response matrix of a 2D IIR digital filter. By using the SVD, 2D magnitude specifications can be decomposed into a pair of 1D filters, and thus the problem of designing a 2D digital filter can be reduced to the one of designing a pair of 1D digital filters or even only one 1D digital filter. The stimulation results show the proposed method has the better performance of the minimum attenuation between the passband and stopband. Copyright (C) 2007 Te-Jen Su et al.
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