Correct-by-construction code generation from hybrid automata specification

Abstract

In the last years hybrid automata have been applied in the design and verification of embedded systems. Once a hybrid model of the system has been proved to be correct with respect to the desired properties, it would be valuable to extract a correct-by-construction HW/SW implementation of it. This work discusses a methodology and a corresponding tool chain that allow to extract a HW/SW implementation of a controller modeled by a subclass of timed automata, named elastic controllers, operating in an environment represented by a hybrid automaton. The required tools have been either developed from scratch or extended from the current state-of-the-art in order to support an automated flow from hybrid automata specifications to correct-by-construction discrete implementations described in the SystemC language

Interactive presentation abstract: Reusing of properties after discretization of hybrid automata

“…The developed methodology ( Figure 1) relies on the hybrid model discretization process proposed in [3] and is divided into the three phases summarized below: 1) Formal verification of the hybrid system. This phase consists of verifying the correctness of the hybrid model M of a hybrid system, against the set P of properties which represent the specifications that the system should satisfy.…”

“…For this reason, once the hybrid model of the system is proved to be correct, is still necessary to derive an implementable model of the hybrid system. Very few works in literature have focused on developing techniques for extracting a correct by construction HW/SW implementation from hybrid automata [2], [3]. Unfortunately, these approaches are able to refine, into a systematic way, only a subclass of hybrid automata, thus they allow to automatically implement only a small class of hybrid systems.…”

“…During such transitions, the supply voltage must follow a linearly rising/falling reference voltage as closely as possible. The PSS implementation and the related ∆ constraints have been obtained by using the approach in [3]. In particular, the module that controls the supply voltage value (i.e., the controller) has been automatically refined (by means of a SystemC implementation), while the module implementing the linearly rising/falling reference voltage (i.e., the voltage unit) has been manually defined (by using the SystemC-AMS library) considering the implementation constraints synthesized for the PSS.…”

A Platform-Based Design Methodology With Contracts and Related Tools for the Design of Cyber-Physical Systems

“…Two synthesis (mapping) approaches have also been presented that can incorporate finite-precision sensors and actuators as well as the finite response time of the controller [103], [104]. In these works, the synthesis problem is addressed for two sub-classes of hybrid automata, namely elastic controllers, and lazy linear hybrid automata, operating in an environment represented by hybrid automata.…”

“…The result is that any correct Almost ASAP controller can be implemented by a program on a hardware if this hardware is fast enough. The first paper [103] presents a corresponding automated tool chain that can extract from an elastic controller a correct-by-construction HW/SW implementation described in SystemC. On the other hand, lazy linear hybrid automata [107] are used to model the discrete-time behavior of control systems containing finite-precision sensors and actuators interacting with their environment under bounded delays.…”