How do inner loops work? Using designated control inputs to simplify control design
Published in None, 2025
The traditional approach to synthesizing inner-loop/outer-loop controllers is to designate a control input, design an inner-loop controller to specify the actuator control input, close the inner loop by using a sensor to measure the designated control input, and then design the outer-loop controller to specify the requested value of the designated control input to be followed by the designated control input. This article illustrates how inner-loop/outer-loop control architectures are designed, and then investigates how the performance of the inner-loop controller impacts the performance of the overall control system. Three examples are presented to illustrate the design process for inner-loop/outer-loop control architectures.
Recommended citation: J. A. Paredes Salazar, R. A. Alhazmi, S. A. U. Islam, J. M. Portella Delgado, A. Goel, and D. S. Bernstein, “How do inner loops work? Using designated control inputs to simplify control design,” submitted to IEEE Contr. Syst. Mag.