Papers by Roberto Galeazzi
Gas bearings are popular for their high speed capabilities, low friction and clean operation, but... more Gas bearings are popular for their high speed capabilities, low friction and clean operation, but su er from poor
damping, which poses challenges for safe operation in presence of disturbances. Enhanced damping can be achieved
through active lubrication techniques using feedback control laws. Such control design requires models with low
complexity, able to describe the dominant dynamics from actuator input to sensor output over the relevant range of
operation. The mathematical models based on first principles are not easy to obtain, and in many cases, they cannot
be directly used for control design due to their complexity and parameter uncertainties. As an alternative, this paper
presents an experimental technique for ”in situ” identification of low complexity models of the entire rotor-bearingactuator
system. Using grey-box identification techniques, the approach is shown to be easily applied to industrial
rotating machinery with gas bearings and to allow for subsequent control design. The paper shows how piezoelectric
actuators in a gas bearing are eciently used to perturb the gas film for identification over relevant ranges of rotational
speed and gas injection pressure. Parameter-varying linear models are found to capture the dominant dynamics of the
system over the range of operation. Based on the identified models, decentralised proportional control is designed and
is shown to obtain the required damping in theory as well as in a laboratory test rig.
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Papers by Roberto Galeazzi
damping, which poses challenges for safe operation in presence of disturbances. Enhanced damping can be achieved
through active lubrication techniques using feedback control laws. Such control design requires models with low
complexity, able to describe the dominant dynamics from actuator input to sensor output over the relevant range of
operation. The mathematical models based on first principles are not easy to obtain, and in many cases, they cannot
be directly used for control design due to their complexity and parameter uncertainties. As an alternative, this paper
presents an experimental technique for ”in situ” identification of low complexity models of the entire rotor-bearingactuator
system. Using grey-box identification techniques, the approach is shown to be easily applied to industrial
rotating machinery with gas bearings and to allow for subsequent control design. The paper shows how piezoelectric
actuators in a gas bearing are eciently used to perturb the gas film for identification over relevant ranges of rotational
speed and gas injection pressure. Parameter-varying linear models are found to capture the dominant dynamics of the
system over the range of operation. Based on the identified models, decentralised proportional control is designed and
is shown to obtain the required damping in theory as well as in a laboratory test rig.
damping, which poses challenges for safe operation in presence of disturbances. Enhanced damping can be achieved
through active lubrication techniques using feedback control laws. Such control design requires models with low
complexity, able to describe the dominant dynamics from actuator input to sensor output over the relevant range of
operation. The mathematical models based on first principles are not easy to obtain, and in many cases, they cannot
be directly used for control design due to their complexity and parameter uncertainties. As an alternative, this paper
presents an experimental technique for ”in situ” identification of low complexity models of the entire rotor-bearingactuator
system. Using grey-box identification techniques, the approach is shown to be easily applied to industrial
rotating machinery with gas bearings and to allow for subsequent control design. The paper shows how piezoelectric
actuators in a gas bearing are eciently used to perturb the gas film for identification over relevant ranges of rotational
speed and gas injection pressure. Parameter-varying linear models are found to capture the dominant dynamics of the
system over the range of operation. Based on the identified models, decentralised proportional control is designed and
is shown to obtain the required damping in theory as well as in a laboratory test rig.