REG NASA-LLIS-1607--2005 Lessons Learned - Fin Actuator System Hinge Torque and Output Transistor Failure.pdf

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1、Lessons Learned Entry: 1607Lesson Info:a71 Lesson Number: 1607a71 Lesson Date: 2005-06-02a71 Submitting Organization: DFRCa71 Authored by: Jonathan BrownSubject: Fin Actuator System/Hinge Torque and Output Transistor Failure Abstract: Component manufacturers advisories, along with low-inductance gro

2、und and power planes/paths within (sub)systems, must be heeded. Following the recommendations from the X43A Flight 1 MIB, the Pegasus actuator system was redesigned to accommodate the need for greater hinge torque. The analog-based legacy actuator system was redesigned for digital drive of the power

3、 output stage to the actuators, an additional actuator was incorporated to provide the necessary torque including margins, and the power supply was increased to provide the required 80+ amps, instead of the previous 40 amp capability. Multiple failures during qualification testing, and the subsequen

4、t technical investigations, proved the lack of understanding between the ideal circuit operation and the impact of system implementation. Low-inductance ground and power planes/paths within (sub)systems are essential for proper operation. Description of Driving Event: Following the recommendations f

5、rom the X43A Flight 1 MIB, the Pegasus actuator system was redesigned to accommodate the need for greater hinge torque. The analog-based legacy actuator system was redesigned for digital drive of the power output stage to the actuators, an additional actuator was incorporated to provide the necessar

6、y torque including margins, and the power supply was increased to provide the required 80+ amps, instead of the previous 40 amp capability. Multiple failures during qualification testing, and the subsequent technical investigations, proved the lack of understanding between the ideal circuit operatio

7、n and the impact of system implementation. Lesson(s) Learned: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-During some of the system testing configurations, the output circuits were energized while no load (actuator) was connected. It is believed

8、that component degradation from this practice resulted in premature failure of output transistors and severe printed circuit board damage. Recommendation(s): All warnings and advisories from component manufacturers regarding implementation and testing must be followed. Energized, high current output

9、 drive circuits should always be connected to a “load” to prevent potential component degradation. Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Aeronautics Researcha71 Space OperationsAdditional Key Phrase(s): a71

10、 Accident Investigationa71 Flight Equipmenta71 Hardwarea71 Safety & Mission Assurancea71 Test & VerificationAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2006-04-18a71 Approval Name: dkruhma71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-