Implementing energy-based controllers in software represents a challenge for software engineers, as additional expertise is required to abide by the physics-domain constraints of energy exchange in the design and structure of the control software. Our paper bridges the gap between software engineering and the physics domain by conveying energy exchange to controlsoftware modelling. We use principles of physical systems and the bond-graph modelling language to identify the mechanisms and constraints of energy exchange and represent them as datacommunication services for software models. This work resulted in metamodels and models for power and energy communication that can facilitate the first-time-right implementation of robotcontrol software.

Composability and modularity in relation to physics are useful properties in the development of cyber-physical systems that interact with their environment. The bond-graph modeling language offers these properties. When systems structures conform to the bond-graph notation, all interfaces are defined as physical "power ports" which are guaranteed to exchange power. Having a single type of interface is a key feature when aiming for modular, composable systems. Furthermore, the facility to monitor energy flows in the system through power ports allows the definition of system-wide properties based on component properties. In this paper we present a metamodel of the bond-graph language aimed to facilitate the description and deployment of software components for cyber-physical systems. This effort provides a formalized description of standardized interfaces that enable physics-conformal interconnections. We present a use-case showing that the metamodel enables composability, reusability, extensibility, replaceability and independence of control software components.This research has received funding from the RobMoSys project (EU project No. 732410) under the subproject EG-IPC. https://robmosys.eu/eg-ipc/.

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Passivity is a sufficient condition for system stability and is particularly convenient in loop-control design. This paper presents an architecture for composing and structuring loop controllers out of generic components with preserved passivity properties. This allows handling passivity at a structural level by monitoring the energy flows. A use case shows how this architecture preserves the passivity and, in consequence, the stability of a robotic system operating under detrimental conditions. This effort facilitates generating loop-control software which passivity is unaffected by its composition and/or operation conditions.