Hello Aisler community,
We are VOID, a student rocketry team from the TU/e with the aim of researching and developing reusable rockets. More specifically, we focus on developing liquid bi-propellant powered rockets with the ability to propulsively land.
At the moment we have two main projects. The first is project Ignis, a rocket designed to compete at the European Rocketry Challenge (EuRoc) in the 3km apogee category. This project is also used as a stepping stone in developing the whole system and learning through it.
The second project is Jackalope which is the Vertical Takeoff Vertical Landing (VTVL) rocket that will perform the propulsive landing hop. Since testing rockets is not so trivial and far from cheap we also have a sub-project Tapeti, which is a drone that also uses the Thrust Vectored Control (TVC) mechanism and thus the dynamics are near identical to the ones that Jackalope will experience. Therefore we use Tapeti as a testing platform to validate all of the Guidance, Navigation and Control (GNC) as well as the avionics.
An integral part of Tapeti is the TVC platform, which is actuated by two rods that are connected to servo motors. These servos are what makes the thrust vector rotate, and therefore they are what determines Tapeti’s attitude. In other words, without the servos functioning flawlessly Tapeti’s fate is sealed, which is exactly where the Servo board comes into play.
Servo board
To keep up with the dynamics of the small drone (speaking in rocket terms) powered by two coaxial BLDC motors, the servos actuating the TVC receive control corrections every 10 ms and can often experience quite some current draw transients. This imposes significantly tougher requirements for powering the servos themselves, as well as requirements for isolation of the rest of the system, as such higher current transients can easily turn into EMI, and other forms of signal integrity degradation.
Moreover, the servos draw current even when simply idle and having them turned on all the time is also not desirable, especially when there is a need for validation of a sub-system disjunct with the function of the servos.
So overall, the function of this PCB is to mainly isolate the power delivered to the servos and provide a way to arm and disarm them.
For the design of the PCB, we used Altium Designer, as Altium is also kind enough to sponsor us and allow us to use all the features, which make the design process significantly smoother.
At the heart of it all is a relatively simple buck converter, which handles the voltage regulation of stepping the main battery voltage down to the voltage accepted by the servos. Around it are the quite generously sized components that enable its proper function. Lastly, there are the connectors to integrate the board into our system.
To satisfy the higher current and heat dissipation requirements, we also chose to use the 2oz copper layers. The PCBs also came out so stunning thanks to the ENIG finish, which makes them truly shine and also helps tremendously with solderability!
Now all of this would not be possible at all without the beautiful AISLER PCB making capabilities. We are incredibly thankful for the sponsorship, as it allows us to iterate and develop the critical sections at a pace that is unmatchable.
Kind regards and remember, pointy way up!