The complexity of linear, fixed-point arithmetic digital controllers is investigated from a Kolmogorov-Chaitin perspective. Based on the idea of Kolmogorov-Chaitin complexity, practical measures of complexity are deve...
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The complexity of linear, fixed-point arithmetic digital controllers is investigated from a Kolmogorov-Chaitin perspective. Based on the idea of Kolmogorov-Chaitin complexity, practical measures of complexity are developed for statespace realizations, parallel and cascade realizations, and for a newly proposed generalized implicit state-space realization. The complexity of solutions to a restricted complexitycontroller benchmark problem is investigated using this measure. The results show that from a Kolmogorov-Chaitin viewpoint, higher-order controllers with a shorter word-length may have lower complexity and better performance, than lower-order controllers with longer word-length.
A novel design methodology of corrective control is proposed for fault-tolerance against transient faults in input/output asynchronous sequential machines. The main objective is to lessen controller complexity by prop...
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A novel design methodology of corrective control is proposed for fault-tolerance against transient faults in input/output asynchronous sequential machines. The main objective is to lessen controller complexity by proposing a structure of corrective control that employs no state observer, which is required in the former studies for input/output control of asynchronous machines. The form of the output feedback is also simplified as a unit character instead of bursts. Although the exact identification of the machine's state is infeasible, the proposed controller achieves immediate fault-tolerance against transient faults that cause unauthorised state transitions. As a case study, the authors apply the proposed control scheme to implementing configuration controllers for space-borne field programmable gate array with hardware redundancy in which single event upset faults may happen by the radiation effect.
Linear quadratic optimal control theory is applied to the problem of bank-to-turn control in a CLOS guidance system. Both stationary and moving targets are treated, and the trade-off between controller complexity and ...
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Linear quadratic optimal control theory is applied to the problem of bank-to-turn control in a CLOS guidance system. Both stationary and moving targets are treated, and the trade-off between controller complexity and autopilot realisability examined. The optimality of conventional control ideas is assessed. Finally, simulation results using a practical autopilot model confirm that these new controllers give improved guidance accuracy and reduced susceptibility to pitch-yaw crosscoupling.
The optimiser of a (multi) parametric linear program (pLP) is a piecewise affine function defined over a polyhedral subdivision of the set of feasible states. Once this affine function has been pre-calculated, the opt...
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The optimiser of a (multi) parametric linear program (pLP) is a piecewise affine function defined over a polyhedral subdivision of the set of feasible states. Once this affine function has been pre-calculated, the optimal solution can be computed for a particular parameter by determining the region that contains it. This is the so-called point location problem. In this paper, we show that this problem can be written as an additively weighted nearest neighbour search that can be solved in time linear in the dimension of the state space and logarithmic in the number of regions. It is well-known that linear model predictive control (MPC) problems based on linear control objectives (e.g., l- or infinity-norm) can be posed as pLPs, and on-line calculation of the control law involves the solution to the point location problem. Several orders of magnitude sampling speed improvement are demonstrated over traditional MPC and closed-form MPC schemes using the proposed scheme. (c) 2006 Elsevier Ltd. All rights reserved.
Self-excited oscillation is becoming a major issue in low-emission, lean partially premixed combustion systems, and active control has been shown to be a feasible method to suppress such instabilities. A number of rob...
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Self-excited oscillation is becoming a major issue in low-emission, lean partially premixed combustion systems, and active control has been shown to be a feasible method to suppress such instabilities. A number of robust control methods are employed to obtain a feedback controller and it is observed that the robustness to system uncertainty is significantly better for a low complexitycontroller in spite of the norms being similar. Moreover, we demonstrate that closed-loop stability for such a complex system can be proved via use of the integral quadratic constraint method. Open- and closed-loop nonlinear simulations are provided.
Closed-form Model Predictive Control (MPC) results in a polytopic subdivision of the set of feasible states, where each region is associated with an affine control law. Solving the MPC problem on-line then requires de...
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Closed-form Model Predictive Control (MPC) results in a polytopic subdivision of the set of feasible states, where each region is associated with an affine control law. Solving the MPC problem on-line then requires determining which region contains the current state measurement. This is the so-called point location problem. For MPC based on linear control objectives (e.g., 1- or ∞-norm), we show that this problem can be written as an additively weighted nearest neighbour search that can be solved on-line in time linear in the dimension of the state space and logarithmic in the number of regions. We demonstrate several orders of magnitude sampling speed improvement over traditional MPC and closed-form MPC schemes.
A breakthrough in the study of chaos control and synchronization was made in 1990 by,*** et al using a closed-loop feedback method,and Pecora and Carroll using replacement *** various techniques have been proposed for...
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A breakthrough in the study of chaos control and synchronization was made in 1990 by,*** et al using a closed-loop feedback method,and Pecora and Carroll using replacement *** various techniques have been proposed for the control and synchronization of chaotic *** particular,the active control scheme proposed by Bai and Lonngren has received considerable attention in the last decade due to its simplicity and *** important modification of this technique is the recently introduced active control technique based on the Lyapunov stability theory and Routh-Hurwitz criteria by Lei.
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