RTOS to create resilient flight control system

NASA Goddard Space Flight Centre's Wallops Flight Facility is using the OSE real-time operating system to develop a state-of-the-art adaptive flight control system.

NASA Goddard Space Flight Centre's Wallops Flight Facility is using the OSE real-time operating system to develop a state-of-the-art adaptive flight control system.

To achieve autonomous, resilient flight control, the system will perform mission planning and management functions, incorporate built-in test and fault-detection algorithms, perform primary flight control functions as well as respond to faults and aberrant conditions.

A small UAV (unmanned aerial vehicle) will be used as an engineering test-bed and is itself designed with a robust, resilient architecture.

"NASA's primary concern is to build a highly reliable flight control system.

The flight manager needs to identify and make immediate adjustments for problems in the control links or for other conditions such as wind gusts", said Philip Ward, Guidance, Navigation and Control Systems Engineer at NASA Goddard Space Flight Centre's Wallops Flight Facility.

"The successful completion of a mission depends on the ability to intelligently evaluate current conditions and make adjustments as needed".

"OSE understands safety-critical systems such as NASA's unmanned aerial vehicles where the loss of the telemetry link cannot precipitate loss of aircraft or mission", states Vance Hilderman, Vice President of US Operations, OSE Systems.

"We are proud that NASA has recognised the mission-critical experience OSE brings to the table".

Designed for high-reliability and fault-tolerant conditions, the OSE RTOS provides the distributed, multicore organisation needed for this sophisticated flight-control matrix.

A series of control algorithms provide redundant commands to two Motorola PowerPC flight computers that ensure safe preflight automated tests, autonomous take-off, control of mission and landing, are fully organised via a series of layers.

The first layer, providing servo deflections based on sensed altitude, speed and attitude errors, and second layer, involving relative location and speed with respect to desired waypoints, are monitored by a third that checks status of the two control loops, mission progress, fuel load and other pertinent sensor data.

A fussy inference system detects anomalous conditions and makes adjustments.

High reliability is central to the design of this autonomous flight control system.

The OSE RTOS hosts the flight software on two PowerPC flight computers in a PC/104 footprint.

The OSE link handler together with the Altera programmable logic device will cross-strap the redundant servo command signals from the two computers to provide a highly reliable, fault-resistant environment.

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