Off-the-Shelf Servo Drive Selection and Test Plan for Future Integration Into the S19E Sounding Rocket Guidance System

Sammanfattning

Equipping a sounding rocket with a guidance system one might be provided with increased control of the vehicle during flight, from lowering impact dispersion which enable launching from a wider range of launch sites, to increasing the vehicle's wind tolerance meaning lower waiting time for better conditions. Beyond Gravity Sweden's portfolio of sounding rocket guidance systems include the S19E, a canard controlling guidance module ready to be mounted on the payload stack of the customers launch vehicle. Upgrades are always investigated and Beyond Gravity is seeking to exchange the servo drives for the canards' electrical servos for an off-the-shelf drive instead. The aim of this thesis is therefore to initiate this process by selecting a drive and develop a test program so that Beyond Gravity can evaluate its performance relative to the existing hardware. The selection process is based on the ECSS standard for "OTS item utilization in space systems", wherein two drives were initially identified, but only one of them remained after the first screening. The remaining drive (the Gold Solo Hornet digital servo drive) was further characterised before the decision was made to procure a unit, to be tested with a newer revision of electrical servos. A test programme was then developed based on the ECSS standard for "Testing", but modified to fit the scope of qualification stage servo drive testing on equipment level. The output of the thesis is a test specification for both functional and performance tests, and will form a reference for Beyond Gravity to perform said future tests on the servo drive. During the thesis work additional studies were carried out of what other future steps for Beyond Gravity might be preferred. Conclusions of future work include drive programming, initailly with simple user programs and later with full S19E integration in mind. Other work include the evaluation of test results, which inevitably shall be compared to the existing hardware. Should the drive pass the future testing then Beyond Gravity can proceed with more extensive testing and qualification activities, such as environmental and integration tests, before acceptance testing and finally an upgraded guidance system.