Current Issue : October - December Volume : 2013 Issue Number : 4 Articles : 5 Articles
We present a satellite attitude control system design using low-cost hardware and software for a 1U CubeSat. The attitude control\r\nsystem architecture is a crucial subsystem for any satellite mission since precise pointing is often required to meet mission objectives.\r\nThe accuracy and precision requirements are even more challenging for small satellites where limited volume, mass, and power are\r\navailable for the attitude control system hardware. In this proposed embedded attitude control system design for a 1U CubeSat,\r\npointing is obtained through a two-stage approach involving coarse and fine control modes. Fine control is achieved through the\r\nuse of three reaction wheels or three magnetorquers and one reaction wheel along the pitch axis. Significant design work has been\r\nconducted to realize the proposed architecture. In this paper, we present an overview of the embedded attitude control system\r\ndesign; the verification results fromnumerical simulation studies to demonstrate the performance of a CubeSat-class nanosatellite;\r\nand a series of air-bearing verification tests on nanosatellite attitude control system hardware that compares the performance of the\r\nproposed nonlinear controller with a proportional-integral-derivative controller....
We present a constructive solution to the problem of full output feedback equivalence, of linear, minimal, time-invariant systems.\r\nThe equivalence relation on the set of systems is transformed to another on the set of invertible block Bezout/Hankel matrices\r\nusing the isotropy subgroups of the full state feedback group and the full output injection group. The transformation achieving\r\nequivalence is calculated solving linear systems of equations.We give a polynomial version of the results proving that two systems\r\nare full output feedback equivalent, if and only if they have the same family of generalized Bezoutians. We present a new set of\r\noutput feedback invariant polynomials that generalize the breakaway polynomial of scalar systems....
We consider a design problem of a variable gain robust output feedback controller with guaranteed L2 gain performance for a\r\nclass of Lipschitz uncertain nonlinear systems. The proposed variable gain robust output feedback controller achieves not only\r\nrobust stability but also a specified L2 gain performance. In this paper, we show that sufficient conditions for the existence of the\r\nproposed variable gain robust output feedback controller with guaranteedL2 gain performance are given in terms of linear matrix\r\ninequalities (LMIs). Finally, a simple numerical example is included....
The new hybrid active filter (HAF) is composed of the larger-capacity passive filter banks and the smaller-capacity active filter. It is\r\ndifficult to tune the parameters of a PI controller using the DC capacitor voltage control. In this paper, the improved particle swarm\r\noptimization (improved PSO) algorithm is proposed to solve the coordinated design problem, and the neural network weights as\r\nthe particle swarm optimization are adopted to optimize the system parameters. Comparing with the conventional PI controller,\r\nthe results of PINN controller prove the effectiveness of designed method on both the transient and steady-state performance of\r\nthe hybrid active filter DC bus voltage (HAFDV) controllers....
For a class of ItÃ?â? o stochastic linear systems with the Markov jumping and linear fractional uncertainty, the stochastic stabilization\r\nproblem is investigated via state feedback and dynamic output feedback, respectively. In order to guarantee the stochastic stability\r\nof such uncertain systems, state feedback and dynamic output control law are, respectively, designed by using multiple Lyapunov\r\nfunction technique and LMI approach. Finally, two numerical examples are presented to illustrate our results....
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