K-modification and a novel approach to output feedback adaptive control

State feedback;Adaptive control;Flexible system;Uncertain system;Output feedback

Kim, Kilsoo ; Aerospace Engineering

University:Georgia Institute of Technology

Department:Aerospace Engineering

关键词: State feedback;    Adaptive control;    Flexible system;    Uncertain system;    Output feedback;   

Others  :  https://smartech.gatech.edu/bitstream/1853/39579/1/kim_kilsoo_201105_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

This dissertation presents novel adaptive control laws in both state feedback and output feedback forms. In the setting of state feedback adaptive control K-modification provides a tunable stiffness term that results in a frequency dependent filtering effect, smoothertransient responses, and time delay robustness in an adaptive system. K-modificationis combined with the recently developed Kalman filter (KF) based adaptive control andderivative-free (DF) adaptive control. K-modification and its combinations with KF adaptivecontrol and DF adaptive control preserve the advantages of each of these methods andcan also be combined with other modification methods such as - and e-modification. Anadaptive output feedback control law based on a state observer is also developed. The mainidea behind this approach is to apply a parameter dependent Riccati equation to outputfeedback adaptive control. The adaptive output feedback approach assumes that a stateobserver is employed in the nominal controller design. The observer design is modifiedand employed in the adaptive part of the design in place of a reference model. This iscombined with a novel adaptive weight update law. The weight update law ensures thatestimated states follow both the reference model states and the true states so that bothstate estimation errors and state tracking errors are bounded. Although the formulation isin the setting of model following adaptive control, the realization of the adaptive controlleruses the observer of the nominal controller in place of the reference model to generate anerror signal. Thus the only components that are added by the adaptive controller are therealizations of the basis functions and the weight adaptation law. The realization is evenless complex than that of implementing a model reference adaptive controller in the case ofstate feedback. The design procedure of output feedback adaptive control is illustrated withtwo examples: a simple wingrock dynamics model and a more complex aeroelastic aircrafttransport model.