A Systematic Review of Hardware-in-The-Loop (HiL) Frameworks for Internet of Things Applications.

Hardware-in-the-Loop (HiL) testing has emerged as a pivotal technique for validating and enhancing the performance of control systems across various industries, notably in automotive and embedded manufacturing sectors. This paper provides an extensive exploration of HiL testing methodologies and their application in the Internet of Things (IoT) domain. HiL testing involves simulating real-world conditions by integrating specialized simulation software and hardware components, facilitating realistic evaluation of controllers' functionality and behaviour. Different variants of HiL, such as Model-in-the-Loop (MiL), Software-in-the-Loop (SiL), Processor-in-the-Loop (PiL), and Hardware-in-the-Loop (HiL), are discussed within the broader context of XiL (Anything-in-the-Loop) models. The paper underscores the significance of HiL testing in optimizing the development process, reducing costs, and minimizing hazards. It elaborates on the utilization of HiL testing to validate intricate control algorithms, simulate fault scenarios, and assess system behaviour under diverse conditions. The integration of HiL testing with IoT applications is examined, highlighting the potential benefits in areas like smart cities, industrial IoT, healthcare, agriculture, and energy management. The study presents a novel fault injection framework within HiL testing, allowing real-time analysis of complex systems' responses to simulated faults. This framework aids in identifying vulnerabilities and evaluating system reliability, thereby enhancing safety and performance. The authors introduce the concept of sensor schema, Observations & Measurements (O&M), and Sensor Web Enablement (SWE) as key components for efficient sensor data integration, sharing, and interoperability. The paper concludes by emphasizing the indispensable role of Hardware-in-the-Loop testing in fostering innovation, safety, and efficiency in the IoT landscape. By offering a comprehensive overview, analysis, and practical insights into the application of HiL testing methodologies, this research contributes to the advancement of robust and reliable IoT systems. [ABSTRACT FROM AUTHOR]