Fuzzy logic comes into sharper focus

Fuzzy logic comes into sharper focus
Ten years after the initial flurry of interest in fuzzy logic for embedded control, STMicroelectronics (ST) has decided to revisit the field with a hybrid microcontroller architecture the company has aimed at domestic appliances and industrial controls.

The Five architecture combines a conventional register-based microcontroller with what the company calls a "decision processor" that implements the fuzzy logic routines.

The company has developed two 8bit architectures so far with plans for a 32bit device in the future. The core microcontroller performs arithmetic and conventional operations but hands off fuzzy logic operations to the decision processor.

The decision processor has hardwired routines for performing typical fuzzy logic operations, which are typically a combination of maths-intensive operations and if-then decisions.

The idea behind adding the decision processor is to speed up operations that take a long time on classic low-end microcontrollers.

One application that ST has identified is in sensor fusion or conversion. A cheap thermistor can be used in place of a pressure sensor in a vacuum cleaner because the temperature rises as the airflow falls.

By developing fuzzy rules, ST claims its approach can be handled in 20 instructions using the decision processor in place of 80 or more on the host microcontroller.