We present gusimplewhiteboard, a software architecture analogous to ROS:services and ROS:messages, that enables the construction and extremely efficient inter-process relaying of message-types as C++11 objects, All gusimplewhiteboard objects reside in shared memory. Moreover, our principle is to use idempotent message communication, in direct contrast to previously released platforms for roboticmodule communication, that are based on an event-driven subscriber model that queues and multi-threads. We combine this with compiled, time-triggered, logic-labeled finite state machines (llfsms) the are executed concurrently, but scheduled sequentially, in an extremely efficient manner, removing all race conditions and requirements for explicit synchronisation. Together, these tools enable effective robotic behaviour design, where arrangements of llfsms can be organised as hierarchies of machines and submachines, enabling composition of very complex systems. They have proven to be very powerful for Model-Driven Development, capable of simulation, validation, and formal verification.

Simulation of models that specify behaviour of software in robots, embedded systems, and safety critical systems is crucial to ensure correctness. This is particularly important in conjunction with modeldriven development, which is highly prevalent due to its numerous benefits. We use vectors of finite-state machines (FSMs) as our modelling tool. Our FSMs can have their transitions labeled by expressions of a common sense logic, and they are more expressive than other modelling approaches (such as Behavior Trees, Petri nets, or plain FSMs). We interpret the models using the same round-robin scheduler which is integrated into the simulator. Execution on a platform is exactly the same as in the simulator (where sensors and actuators are masqueraded by proxies) and coincides with the generator of the Kripke structure for formal modelchecking. In three ubiquitous case studies we show that our simulation discovers issues where those models were incomplete, ambiguous, or incorrect. This further illustrates that simulation and monitoring need to complement formal verification.

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WiFi is prevalent in mobile robotics and the Internet of Things (IoT) despite the fact that many applications in these environments require real-time communication. WiFi does not guarantee timeliness and often introduces unbounded communication delays. We present TTWiFi, a time-triggered protocol for fault-tolerant real-time communication between devices situated in a broadcast domain, that only requires minor changes to IEEE 802.11 parameters and remains standards-compliant in critical aspects. We implemented TTWiFi on a representative platform and benchmarked our implementation with TCP and UDP over unmodified WiFi. Our results demonstrate that unlike the latter, TTWiFi has the ability to maintain communication in a congested environment while exhibiting fail-silent behaviour crucial for fault tolerance and real-time communication.