Feed-back quality control in the baking industry using fuzzy sets

A methodology for the closed loop control of biscuit quality during baking is proposed and was validated during several experiments. This methodology involves expert knowledge which is captured in a modular way. Three modules are involved in the control strategy of the process. The first module reproduces sensory evaluation by the operator. The second module diagnoses the state of the process with respect to quality state of biscuits. Finally, a decision module supervises the actuators of the process. Different fuzzy concepts are applied within these modules and fuzzy information is processed through the control chain. Results show that using only II rules, all components of quality are controlled with accuracy and robustness. This is particularly interesting in the light of the complexity of the process. Such a modular approach makes it possible to follow the evolution of quality during the process, in successive steps which are easily recorded and interpreted by experts. This approach could be envisaged as an operator decision support system.