A Generic Interface for x-in-the-Loop Simulations Based on Distributed Co-Simulation Protocol

Abstract

Co-simulation is a key step in the development of today's complex cyber-physical systems (CPS), specially in the integration and validation activities. However, performing a co-simulation involving models developed in different environments and possibly deployed in different platforms with mixed real-time and non real-time constraints is a challenging engineering task. A promising technology that could help overcome communication and synchronisation difficulties is the non-proprietary standard Distributed Co-simulation Protocol (DCP). This standard defines an application-level communication protocol, independent of the platform and the communication medium, that regulates the exchange of information between the co-simulation entities. This paper presents a co-simulation interface based on the DCP standard. It offers a novel approach to apply the DCP standard. Instead of using it as a model encapsulation mechanism, having to develop an specific DCP slave for each application, it is proposed to use it as a generic co-simulation interface. To this end, a Simulink library has been developed, allowing to connect models developed in Simulink with the outside world in an standardised way. Moreover, by exploiting the code generation potential of Simulink, a wide variety of devices become accessible, thus enabling x-in-the-loop simulations, which are commonly used tests in the verification and validation process of CPSs. This library has been tested in a soft real-time co-simulation application between a Simulink instance and an application running on a Xilinx Zynq Ultrascale+ System-on-Chip. As an additional contribution, an analysis of DCP synchronisation problems when simulating closed-loop systems composed of two slaves is performed. Finding that the main causes are the occurrence of random delays and that the simulations of the two slaves start at an arbitrary time. A possible solution to this problem is also presented. INDEX TERMSControl systems, co-simulation interface, distributed co-simulation protocol, model-based design, model testing, simulink, x-in-the-loop.

Testing the Verification and Validation Capability of a DCP-Based Interface for Distributed Real-Time Applications

“…To bridge this gap, we proposed [6] and presented [7], a co-simulation architecture based on non-proprietary standards that facilitates coupling between different M&S environments and hardware platforms. By relying on a non-proprietary standard such as the Distributed Co-Simulation Protocol (DCP) [17], the architecture is implementable without any intellectual property restrictions and, on top of that, it is compatible with any other DCP secondary.…”

“…In comparison with the DCP, we propose a generic cosimulation interface, i.e., the system to be communicated is independent to the interface and there is no need to develop a specific secondary for each application. This is explained in [7], where we extended the scope of the DCP by creating a Simulink library, allowing for Simulink to be easily integrated not only into our architecture, but also into any DCP application.…”

“…The motivation for this work is to develop a tool-agnostic method that enables the linking of different modeling and simulation tools and various hardware platforms. In [6], we argued the lack of a language and platform-independent co-simulation architecture to address this problem, and in [7], we proposed a solution, presenting an architecture based on the non-proprietary Distributed Co-Simulation Protocol (DCP) standard. Nevertheless, we did not explore how this could be deployed on different hardware platforms nor demonstrate how the verification and validation process can be simplified.…”

Intelligent Embedded Systems Platform for Vehicular Cyber-Physical Systems

“…They propose that effective hardware and software co-design is a well-established approach that can streamline and parallelise system development. Similarly, Segura et al [56] use a distributed co-simulation protocol to propose a generic interface for CPS simulation and development.…”

A Real-time Degradation Abatement Technique in Hybrid Electric Vehicle using Data-Driven Methods

“…The controller hardware-in-the-loop (CHIL) experiments are conducted to test and validate algorithms or frameworks in realtime systems using real-time simulators and controllers [38]. Therefore, the execution of the proposed strategy is exemplified through a CHIL experiment.…”