Abstract:
Geotechnical centrifuges are valuable instruments for physical modelling of complex
geotechnical problems in a controlled laboratory setting. In comparison to full-scale testing, scaled models are cost effective to construct and instrument and, when tested in a
geotechnical centrifuge at increased centrifugal accelerations, are capable of replicating
full-scale stress–strain soil behaviour. Centrifuge modellers require specialised hardware
and instruments capable of functioning under high accelerations. Such hardware is costly,
nearly always purpose built, and often rely on commercial, closed-source data acquisition
systems, hardware and control systems.
This paper demonstrates a novel and versatile, low cost, open source logger and control
system that works in parallel alongside existing centrifuge hardware. This solution, termed
Fly-by-Pi, was developed using the Raspberry Pi microcomputer. The system provides
closed-loop control of linear actuators with the ability to operate in either cyclic, monotonic, or static load- or displacement-control. The control mechanism can be reprogrammed according to experimental requirements, even during flight in the centrifuge.
Three independent experiments are described which included the Fly-by-Pi controller as
a key component in their operation. Based on the experience gained during these experiments, the authors encourage wide-spread adoption of open-sourced hardware solutions
in extreme testing environments.
