A Case Study on the Application of Digital Twins for Enhancing CPS Operations

TL;DR

The paper addresses the challenge of maintaining high availability in complex CPS with limited onboard resources by leveraging Digital Twins (DTs) to offload computations and provide fault-tolerance. It presents an empirical evaluation on the fortissimo rover using FMI-based co-simulation (Maestro on the DT, ROSCo on the PT) and AMQP/RabbitMQ for communication, including fault injection to test fallback mechanisms. The key findings show that a DT can (i) augment the physical system’s functionality, exemplified by an advanced Adaptive Cruise Control (ACC), and (ii) enhance fault tolerance by autonomously taking over tasks from malfunctioning components, thereby reducing downtime. The work highlights practical implications for industry, offering a concrete DT-PT integration pattern while acknowledging limitations in realism and real-time guarantees, and suggests future directions toward safety-critical validation and DevOps-aligned DT-PT co-development.

Abstract

To ensure the availability and reduce the downtime of complex cyber-physical systems across different domains, e.g., agriculture and manufacturing, fault tolerance mechanisms are implemented which are complex in both their development and operation. In addition, cyber-physical systems are often confronted with limited hardware resources or are legacy systems, both often hindering the addition of new functionalities directly on the onboard hardware. Digital Twins can be adopted to offload expensive computations, as well as providing support through fault tolerance mechanisms, thus decreasing costs and operational downtime of cyber-physical systems. In this paper, we show the feasibility of a Digital Twin used for enhancing cyber-physical system operations, specifically through functional augmentation and increased fault tolerance, in an industry-oriented use case.

Figures (1)

• Figure 1: (a) Example PT and DT models generated from the fortissimo rover development model for functional augmentation, i.e. for Experiment 1. The red arrows represent the the input-output connections between the PT and DT. The Supervisor component provides visualisation of the PT's and DT's ACC behavior to operators. (b) Left side, Exp. 1: Rover drives, ACC is activated at 08:38:46. DT heartbeat received on the PT (top). Target Acceleration values from the ACC on the DT and PT respectively (middle). Target Velocity values from the ACC on the DT and PT respectively (bottom). Until 08:38:46 the PT is controlled by the DT (dashed blue line). After, the PT takes over (red line). Right side, Exp. 2: Rover drives, ACC is activated at 09:03:04. At 09:05:04 the PT ACC is killed and DT ACC takes over. DT heartbeat received on the PT (top). Target Acceleration values from the ACC on the DT and PT respectively (middle). Target Velocity values from the ACC on the DT and PT respectively (bottom). Before 09:05:50, the PT uses its own ACC (red line). After, it is controlled by the DT (blue line).