Control-Oriented MIMO Modeling for Optical Tissue Microdissection

Optical tissue microdissection selectively heats up highly light absorbing tumor tissue samples to achieve cancer cell extraction, thus, reducing misdiagnoses resulted from contamination of noncancerous cells. Several physics-based models have been proposed and validated for describing the photothermal effect during the microdissection process. However, control-oriented models that can be used for feedback control design are severely deficient. In this study, we propose a multiple input multiple output (MIMO) control model for the process. By mass and heat balance, the model is presented in Hammerstein form, which consists of a nonlinear steady state block coupled by a linear dynamic element, and uses laser power and scan speed as inputs and melt pool height and temperature as outputs. The lumped parameters of the model are identified by matching with the response of the height and the temperature that are obtained by our proposed physical model. The result shows highly close between the outputs of both models. This model can be used for feedback control design to optimize the microdissection process.

Chang-Mu Han and Benjamin Shapiro, "Control-Oriented MIMO Modeling for Optical Tissue Microdissection," in preparation.