Automating Verification of State Machines with Reactive Designs and Isabelle/UTP

State-machine based notations are ubiquitous in the description of component systems, particularly in the robotic domain. To ensure these systems are safe and predictable, formal verification techniques are important, and can be cost-effective if they are both automated and scalable. In this paper, we present a verification approach for a diagrammatic state machine language that utilises theorem proving and a denotational semantics based on Unifying Theories of Programming (UTP). We provide the necessary theory to underpin state machines (including induction theorems for iterative processes), mechanise an action language for states and transitions, and use these to formalise the semantics. We then describe the verification approach, which supports infinite state systems, and exemplify it with a fully automated deadlock-freedom check. The work has been mechanised in our proof tool, Isabelle/UTP, and so also illustrates the use of UTP to build practical verification tools.Comment: 18 pages, 16th Intl. Conf. on Formal Aspects of Component Software (FACS 2018), October 2018, Pohang, South Kore

Modelling and Verification of Timed Robotic Controllers

Designing robotic systems can be very challenging, yet controllers are often specified using informal notations with development driven primarily by simulations and physical experiments, without relation to abstract models of requirements. The ability to perform formal analysis and replicate results across different robotic platforms is hindered by the lack of well-defined formal notations. In this paper we present a timed state-machine based formal notation for robotics that is informed by current practice. We motivate our work with an example from swarm robotics and define a compositional CSP-based discrete timed semantics suitable for refinement. Our results support verification and, importantly, enable rigorous connection with sound simulations and deployments.</p

Formal Verification of Complex Robotic Systems on Resource-Constrained Platforms

International audienceSoftware constitutes a major part of the development of robotic and autonomous systems and is critical to their successful deployment in our everyday life. Robotic software must thus run and perform as specified. Since most of these systems are used in a hard real-time context, the schedulability of their tasks is a crucial property. In this work, we propose to use formal methods to check whether the tasks of a robotic application are schedulable with respect to a given hardware platform. For this, we automatically translate functional components specified in GenoM into FIACRE, a formal language for timed systems. The generated models integrate realistic real-time schedulers based on the FCFS and the SJF cooperative policies. We use then the model-checker TINA to assert schedulability properties. We carry out experiments on a real robotic system, namely a quadcopter flight controller. We demonstrate that, on its actual hardware, schedulability properties can be formally expressed and verified. We give examples on how we can check other important behavioral and timed properties on the same synthesized models

Sintering and dielectric properties of a technical porcelain prepared from economical natural raw materials

Abstract In this study, the production of a technical porcelain, for the ceramic dielectric applications by using economical natural raw materials, was investigated. The basic porcelain composition was selected consisting of 30 wt% kaolin, 45 wt% potash-feldspar and 25 wt% quartz. The obtained phases in the sintered samples were investigated by X-ray diffraction, Fourier transform infrared spectroscopy analysis, and scanning electron microscopy images. It has been confirmed by these techniques that the main crystalline phases were quartz and mullite. Dielectric measurements of technical porcelains have been carried out at 1 kHz from room temperature to 200 °C. The dielectric constant, loss factor, dielectric loss tangent, and resistivity of the porcelain sample sintered at 1160 °C were 22-25, 0.32-1.80, 0.006-0.07, and 0.2-9 x 1013 Ω.cm, respectively. The value of dielectric constant was significantly high when compared to that of conventional porcelains which did not exceed generally 9

On Reconciling Schedulability Analysis and Model Checking in Robotics

International audienceThe challenges of deploying robots and autonomous vehicles call for further efforts to bring the real-time systems and the formal methods communities together. In this paper, we discuss the practicality of paramount model checking formalisms in implementing dynamic-priority-based cooperative schedulers, where capturing the waiting time of tasks has a major impact on scalability. Subsequently , we propose a novel technique that alleviates such an impact, and thus enables schedulability analysis and verification of real-time/behavioral properties within the same model checking framework, while taking into account hardware and OS specificities. The technique is implemented in an automatic translation from a robotic framework to UPPAAL, and evaluated on a real robotic example

Statistical Model Checking of Complex Robotic Systems

International audienceFailure of robotic software may cause catastrophic damages. In order to establish a higher level of trust in robotic systems, formal methods are often proposed. However, their applicability to the functional layer of robots remains limited because of the informal nature of specifications, their complexity and size. In this paper, we formalize the robotic framework G en oM3 and automatically translate its components to UPPAAL-SMC, a real-time statistical model checker. We apply our approach to verify properties of interest on a real-world autonomous drone navigation that does not scale with regular UPPAAL

Formal Verification of Human-Robot Interaction in Healthcare Scenarios

We present a model-driven approach for the creation of formally verified scenarios involving human-robot interaction in healthcare settings. The work offers an innovative take on the application of formal methods to human modeling, as it incorporates physiology-related aspects. The model, based on the formalism of Hybrid Automata, includes a stochastic component to capture the variability of human behavior, which makes it suitable for Statistical Model Checking. The toolchain is meant to be accessible to a wide range of professional figures. Therefore, we have laid out a user-friendly representation format for the scenario, from which the full formal model is automatically generated and verified through the Uppaal tool. The outcome is an estimation of the probability of success of the mission, based on which the user can refine the model if the result is not satisfactory