Title :
Anti-windup compensation for nonlinear systems via gradient projection: Application to adaptive control
Author :
Teo, Justin ; How, Jonathan P.
Author_Institution :
Dept. of Aeronaut. & Astronaut., MIT, Singapore, Singapore
Abstract :
Control saturation is an important limitation in practical control systems and it is well known that performance degradation or instability may result if this limitation is not effectively addressed. Using ideas from the gradient projection method in nonlinear programming, we propose a new anti-windup scheme for multi-input, multi-output nonlinear dynamic controllers. The key idea is to project the controller state update law onto the tangent plane of the active saturation constraints. To do this, we first extend the gradient projection method to the continuous-time case that can accommodate multiple nonlinear constraints. This is then used for anti-windup compensation, resulting in a hybrid controller that switches its state update law over arbitrary combinations of saturating controls. Simulations on a nonlinear two-link robot driven by an adaptive sliding mode controller illustrates its effectiveness and limitations.
Keywords :
MIMO systems; adaptive control; nonlinear control systems; nonlinear programming; stability; variable structure systems; adaptive control; adaptive sliding mode controller; antiwindup compensation; continuous-time case; control saturation; gradient projection method; hybrid controller; instability; multiinput multioutput nonlinear dynamic controllers; multiple nonlinear constraints; nonlinear programming; nonlinear systems; nonlinear two-link robot; performance degradation; practical control systems; state update law; Adaptive control; Control systems; Degradation; Dynamic programming; Nonlinear control systems; Nonlinear systems; Programmable control; Robots; Sliding mode control; Windup;
Conference_Titel :
Decision and Control, 2009 held jointly with the 2009 28th Chinese Control Conference. CDC/CCC 2009. Proceedings of the 48th IEEE Conference on
Conference_Location :
Shanghai
Print_ISBN :
978-1-4244-3871-6
Electronic_ISBN :
0191-2216
DOI :
10.1109/CDC.2009.5400075