Multivariable tuning regulators for unknown systems

The problem of determining a multivariable robust PI-controller for an unknown linear multivariable stable plant is discussed. A method for constructing a multivariable P-controller, which uses interactions of the plant, is developed. These interactions are detected by observing the output of the plant subject to step-inputs. The developed P-controller form together with the robust multivariable I-controller (Davison, 1976) a robust multivariable PI-controller, the construction of which is also based on step-responses. The controllers are applied to a laboratory-scaled concentration-flow process.