A Giotto-Based Helicopter Control System

Abstract

We demonstrate the feasibility and benefits of Giotto-based control software development by reimplementing the autopilot system of an autonomously flying model helicopter. Giotto offers a clean separation between the platform-independent concerns of software functionality and I/O timing, and the platform-dependent concerns of software scheduling and execution. Functionality code such as code computing control laws can be generated automatically from Simulink models or, as in the case of this project, inherited from a legacy system. I/O timing code is generated automatically from Giotto models that specify real-time requirements such as task frequencies and actuator update rates. We extend Simulink to support the design of Giotto models, and from these models, the automatic generation of Giotto code that supervises the interaction of the functionality code with the physical environment. The Giotto compiler performs a schedulability analysis on the Giotto code, and generates timing code for the helicopter platform. The Giotto methodology guarantees the stringent hard real-time requirements of the autopilot system, and at the same time supports the automation of the software development process in a way that produces a transparent software architecture with predictable behavior and reusable components.

This research was supported in part by the DARPA SEC grant F33615-C-98-3614, the MARCO GSRC grant 98-DT-660, and the AFOSR MURI grant F49620-00-1-0327.