Reconfigurable filtering system for sensorless signal acquisition in machining processes

Abstract

Tool condition monitoring is a major problem that must be handled in order to detect and prevent failures in machine tools. Most modern rotating machines have a servo driver whence it is possible to acquire without sensors a current signal which is associated with cutting forces and cutting tool condition. This paper presents a hardware signal processing unit implemented in a field programmable gate array to acquire and condition signals from several machining processes. The system has been tested in both industrial and laboratory processes, producing satisfactory results. The design is reconfigurable in situ, since a few internal registers are programmed dynamically without recompilation which allows the same unit to be applied in different processes; the content of this memory is a set of filter coefficients. This implementation guarantees an inexpensive stand-alone unit since it does not require computers or microprocessors to process signals from different machinery as preparation for further processing.