Gang Tao

Publications (7)2.11 Total impact

• Article: Adaptive Control of Piecewise Linear Systems: the State Tracking Case.

  Qian Sang, Gang Tao
  IEEE Trans. Automat. Contr. 01/2012; 57:522-528.
• Source

  Available from: ntnu.no

  Conference Proceeding: Adaptive control of piecewise linear systems: The output tracking case

  Qian Sang, Gang Tao
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  ABSTRACT: This paper studies the adaptive control problem of single-input, single-output (SISO) piecewise linear systems, a class of linear systems with switched parameters. A direct state feedback model reference adaptive control (MRAC) scheme is developed for such systems to achieve closed-loop signal boundedness and asymptotic output tracking performance. Simulation results on linearized NASA GTM models are presented to demonstrate the effectiveness of the proposed scheme.
  American Control Conference (ACC), 2011; 08/2011
• Source

  Available from: ntnu.no

  Conference Proceeding: Adaptive control of piecewise linear systems: The state tracking case

  Qian Sang, Gang Tao
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  ABSTRACT: This paper studies the adaptive state feedback for state tracking control problem for piecewise linear systems, which are approximations of nonlinear controlled systems at multiple operating points. Piecewise linear reference model systems are studied and used for generating state trajectories. Adaptive schemes are developed using Lyapunov design methods, and their stability and tracking performance are analyzed and evaluated by simulation examples. Asymptotic tracking performance of such an adaptive control system with a sufficiently rich reference input is shown by simulation results, indicating that certain persistent excitation conditions can be sufficient for ensuring the desired asymptotic tracking in the presence of repetitive system switchings.
  American Control Conference (ACC), 2010; 08/2010
• Source

  Available from: virginia.edu

  Article: Gain Margins of Adaptive Control Systems

  Qian Sang, Gang Tao
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  ABSTRACT: This paper presents a systematic study of the gain margins (GM) of adaptive control systems: the specification of the parameter range of a control gain matrix in a designed adaptive control system for maintaining the desired closed-loop signal boundedness and asymptotic tracking performance. It is proved that the GM is infinity for continuous-time direct model reference adaptive control (MRAC) schemes applied to multi-input, multi-output (MIMO) linear time-invariant (LTI) systems, while it is finite with an upper bound for the discrete-time case. The derived GM results are applicable to systems with adaptive nonlinear or pole placement control designs. Analytical GM result is also obtained for some indirect multivariable MRAC systems; in particular, the GM is infinity but with a lower bound for such systems. Methods for enlarging the GM by proper choices of design parameters are presented. Moreover, the effect of sample time on the GM of sampled-data adaptive control systems is studied, which establishes the relationship between the continuous-time and discrete-time GM results. A simulation example is provided to illustrate some of the theoretical results.
  IEEE Transactions on Automatic Control 02/2010; · 2.11 Impact Factor
• Source

  Available from: ntnu.no

  Conference Proceeding: Performance robustness of MRAC under reduction in actuator effectiveness

  Qian Sang, Gang Tao
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  ABSTRACT: The problem of performance robustness of model reference adaptive control (MARC) schemes under reduction in actuator effectiveness (loss-of-effectiveness) is studied in this paper. The reduction is modeled by an uncertain gain matrix representing the actuator effectiveness at the control inputs. MRAC systems are analyzed to determine the robustness of the desired closed-loop performance of stability and asymptotic tracking with respect to such reductions. Conclusions are drawn for direct multivariable MRAC as well as indirect MRAC for both continuous-time and discrete-time schemes. A simulation study is presented to illustrate some of the theoretical results.
  American Control Conference, 2009. ACC '09.; 07/2009
• Source

  Available from: ntnu.no

  Conference Proceeding: Gain margins of multivariable MRAC systems

  Qian Sang, Gang Tao
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  ABSTRACT: This paper studies the gain margins (GM) of multivariable model reference adaptive control (MRAC) systems: the parameter range of a control gain matrix in a designed MRAC system for maintaining the desired closed-loop signal boundedness and asymptotic output tracking. Analytical GM results are obtained for both continuous-time and discrete-time direct MRAC schemes applied to multi-input multi-output (MIMO) LTI systems. The GM problem is also studied for a class of indirect multivariable MRAC systems.
  Decision and Control, 2008. CDC 2008. 47th IEEE Conference on; 01/2009
• Source

  Available from: virginia.edu

  Conference Proceeding: Gain margins of model reference adaptive control systems

  Qian Sang, Gang Tao
  [show abstract] [hide abstract]
  ABSTRACT: This paper studies the gain margins of model reference adaptive control (MRAC)systems: the range of a control gain in a designed adaptive control system, which is sufficient for closed-loop signal boundedness and asymptotic tracking. Analytical results are obtained for four MRAC schemes: direct and indirect, continuous-time and discrete-time, applied to single-input single-output LTI systems. Simulation results are presented to illustrate some of the results.
  Intelligent Control and Automation, 2008. WCICA 2008. 7th World Congress on; 07/2008