Evolvable hardware: From on-chip circuit synthesis to evolvable space systems

Evolvable Hardware (EHW) refers to HW design and self-reconfiguration using evolutionary/genetic mechanisms. The paper presents an overview of some key concepts of EHW, comments on selected applications, and presents a perspective on the development of the field. A fine-grained Field Programmable Transistor Array (FPTA) architecture for reconfigurable hardware is presented as an example of an initial effort toward evolution-oriented devices. Evolutionary experiments in simulations and with a FPTA chip in-the-loop demonstrate automatic synthesis of electronic circuits. Unconventional circuits, for which there are no textbook design guidelines, are particularly appealing to evolvable hardware. To illustrate this situation, one demonstrates here the evolution of circuits implementing parametrical connectives for fuzzy logics. In addition to synthesizing circuits for new functions, evolvable hardware can be used to preserve existing functions and achieve fault-tolerance, determining circuit configurations that circumvent the faults. These characteristics are extremely important for enabling spacecraft to survive harsh environments and to have long life. Expanding reconfiguration to other types of spacecraft hardware (i.e. optics, MEMS, etc) could lead to evolvable space systems. 1