XPDS
A real-time graphical language for soft and hard real-time programs
...XPDS was developed at the University of Johannesburg as part of a Masters investigation. We've proven it on a number of complete systems - control systems for helicopters, normal and delta fixed-wings, as well as some derivative work like camera control systems and ground station interfaces.
If you try it out drop me a line at sam@adcourses.co.za, I'd appreciate the feedback.