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FlightGear Newsletter May 2010: Difference between revisions
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===XML Autopilot Enhancements=== | ===XML Autopilot Enhancements=== | ||
Several developers have been collaborating to make the autopilot system more flexible, allowing it express the kind of logic found in modern flight control systems without relying on Nasal helpers or custom C++ code. To this end, the expression syntax (used in XML animations) is now also supported in conditions, and in the autopilot inputs (including references). This enables mathematical and trigonometric functions, and operations like min, max and average, to be used in autopilot logic. Another addition is support for 1-bit storage elements, known as flip-flops in digital electronics, which allows many standard autopilot behaviours to be modelled with simpler, clearer XML and fewer helper properties. RS and JK flip-flop are available, as well as the less common D and T types. | Several developers have been collaborating to make the autopilot system more flexible, allowing it express the kind of logic found in modern flight control systems without relying on Nasal helpers or custom C++ code. To this end, the expression syntax (used in XML animations) is now also supported in conditions, and in the autopilot inputs (including references). This enables mathematical and trigonometric functions, and operations like min, max and average, to be used in autopilot logic. Another addition is support for 1-bit storage elements, known as flip-flops in digital electronics, which allows many standard autopilot behaviours to be modelled with simpler, clearer XML and fewer helper properties. RS and JK flip-flop are available, as well as the less common D and T types - the RS type in particular is a good model of the 'arm/disarm' logic found in many automatic flight systems or modes. | ||
As an test-case for the new features, James is replacing the C++ autobrake logic with and XML version - once this is working reliably it will be installed in more aircraft, and should serve as an example for similar systems, for example auto-spoilers. | As an test-case for the new features, James is replacing the C++ autobrake logic with and XML version - once this is working reliably it will be installed in more aircraft, and should serve as an example for similar systems, for example auto-spoilers. | ||