Nonlinear control of mass flow controller devices using sliding mode
AssigneeIllinois Tool Works Inc.
InventorsAhmed H. EL-SHAER, Jeffrey L. WHITELEY
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Abstract
The disclosed embodiments include a mass flow controller that implements a systematic sliding mode control algorithm that achieves robust and consistent flow-rate set-point tracking. Advantages of the disclosed embodiments include, but not limited to, rapid prototyping of easy-to-maintain embedded firmware and ease-of-tuning of controller parameters, which significantly reduces complexity of controller tuning. Other embodiments, advantages, and novel features are set forth in the detailed description.
Claims20
A method of implementing a closed loop sliding mode control for a mass flow controller, the method comprising:
- implementing a model for the indicated flow rate dynamics as function of key system parameters;
- defining a flow tracking error;
- defining a sliding surface function;
- estimating a rate of change of the flow tracking error;
- and
- deriving a control input function.
A mass flow controller for controlling a flow of a fluid, the mass flow controller comprising:
- an inlet for receiving the fluid;
- a flow path in which the fluid passes through the mass flow controller;
- a mass flow meter for providing a signal corresponding to mass flow of the fluid through the flow path;
- a control valve for regulating the flow of the fluid out of an outlet of the mass flow controller;
- and
- a controller configured to execute a closed loop sliding mode control algorithm to apply a valve control signal to adjust the control valve to a desired valve position to control the flow of the fluid out of an outlet of the mass flow controller.
Dependencies are inferred from the claim text.