XtokaxtikoX: A stochastic computing-based autonomous cyber-physical system

Abstract

This paper presents XtokaxtikoX, a fully autonomous cyber-physical system employing only stochastic arithmetic to perform computations on its data-path. Traditional implementations of stochastic computing systems benefit from fast and compact implementation of arithmetic operators, and high tolerance to errors, but depend heavily on the conversion between stochastic bitstreams and binary to implement many parts of the system. Furthermore, if a system requires any interaction with analog electronic components it must have additional ADC/DAC conversion circuitry, which further increases the complexity of the system. Conversely, the proposed work is able to directly translate analog signals into stochastic bitstreams, process the stochastic bitstreams and finally control analog actuators relying only on the information on the stochastic bitstreams. Details on the architectures to accomplish such functionality are presented as well as other stochastic arithmetic units. This paper also presents a small stochastic computing-based autonomous cyberphysical system implemented on a Cyclone IV FPGA to carry out a proof-of-concept.