Quasilinear Control of Systems with Time-Delays and Nonlinear Actuators and Sensors

We investigate Quasilinear Control (QLC) of time-delay systems with nonlinear actuators and sensors. QLC leverages the method of stochastic linearization to replace each nonlinearity with an equivalent gain. The existence of the equivalent gain for a closed loop time-delay system is discussed. To co...

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Bibliographic Details
Main Authors: Huang, Wei-Ping, Brahma, Sarnaduti, Ossareh, Hamid R.
Format: Conference Proceeding
Language:English
Subjects:
Actuators
Delays
Mathematical model
Sensor systems
Stochastic processes
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Summary:We investigate Quasilinear Control (QLC) of time-delay systems with nonlinear actuators and sensors. QLC leverages the method of stochastic linearization to replace each nonlinearity with an equivalent gain. The existence of the equivalent gain for a closed loop time-delay system is discussed. To compute the equivalent gain, both the delay Lyapunov method and the Padé approximant are explored. The method of saturated-root locus (S-RL) is extended to nonlinear time-delay systems, and a QLC-based optimal controller design is presented. Statistical experiments are performed to investigate the accuracy of stochastic linearization compared to a system without time-delay. Results show that stochastic linearization effectively linearizes a nonlinear time-delay system, even though delays generally degrade accuracy. Finally, pitch control in a wind turbine system is introduced as a practical example of a nonlinear time-delay system, and its performance is analyzed to demonstrate the applicability and efficacy of the approach.
ISSN:2378-5861
DOI:10.23919/ACC.2019.8814452