Performance enhancement of regulating systems via actuator saturation

Paul Andrew Herman, Purdue University

Abstract

All physical control systems are subject to actuator saturation. Existing controller design techniques often ignored or avoid actuator saturation at the expense of performance. The primary goal of this investigation is to develop a feedback control design technique that enhances performance of physical regulating systems by intentionally saturating the actuator. This methodology is based in the frequency domain where the effective synthesis of controllers for high order systems with parametric and/or unstructured uncertainty can be performed. This technique facilitates the design of linear controllers which saturate the actuators for large step disturbances while maintaining linear operation for smaller step disturbances. Therefore, this technique provides improved regulating performance relative to existing linear control technology as measured by the maximum step disturbance the system can reject subject to an output constraint. The amount of improvement is realized on a case-by-case basis and is a function of system dynamics and the actuator constraint. This additional regulating performance allows the use of smaller actuators which saturate opposed to larger actuators which operate linearly.

Degree

Ph.D.

Subject Area

Mechanical engineering|Electrical engineering

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