Effect of coupling point selection on distortion in internet-distributed hardware-in-the-loop simulation

The degree to which an Internet-Distributed Hardware-In-the-Loop (ID-HIL) simulation loses fidelity relative to the single-location alternative is referred to as distortion. This paper shows that, besides delay, the choice of coupling point, i.e., the port at which the system model is integrated across the Internet, also affects distortion. To quantify distortion, a frequency-domain metric is proposed using a linear systems framework. This metric is then used to analyse how the choice of coupling point affects distortion, leading to guidelines for selecting a coupling point that gives minimal distortion. The theory is demonstrated on a quarter-car model.