ZETA Sky Observer
Initial Phase
The ZETA Sky Observer has a large cylindrical compartment which serves as a fuselage to carry the flight instruments. We figured out the configuration and connections for system channels and wiring plans with help from our mentor Kanesh as well as references from seniors’ documents. Following the diagram below, the 1st row of connections is responsible for autonomous flight control; the 2nd row is for manual flight control; the 3rd row is for AV video transmission. All 3 lines of connections are connected to the Pixhawk 2.1 flight controller, which coordinates and communicates commands between the ground and air.
Prototype
Prototype images/videos with descriptions.
We first fixed up the old plane that was passed down to us by the seniors to test and run the systems.
Final Product
Final Product images/videos with descriptions.
Release Mechanism
Initial Phase
As mentioned, we aim to revamp the release mechanism of the balloon-drone. Previously, a hot-wire cutdown mechanism was adopted whereby the rope connecting the glider and the balloon would be heated and burnt. This approach while successful, comes with several limitations. At higher altitudes where temperatures become more extreme, the hotwire cutdown mechanism runs a greater risk of failing. Moreover, the heating process takes time which means that the cutting of the wire is not immediate. Hence, we concluded that a mechanical release mechanism would be more promising in ensuring a more immediate and predictable release.
With this idea, we went on to search for design inspirations online and came across the multi-ring release design principle. We shortlisted 2 basic designs, which will be described as follows:
Basic design 1 adopts a release pin that can be pulled out by the torque arm of the servo motor. When the hook is released, the upper blue ring (enlarged in size for display purpose) will drop and pass through the second ring, causing the rest of the rings to be released, hence allowing in the release of the plane drone.
However, in this system, significant tension is applied directly to the line pulling on the release pin as well as the ring that the pin hooks onto. Therefore there exists the risk for unsuccessful release due to great tension and insufficient strength of the torque arm that is attached to the servo motor.
Basic design 2 resembles the three-ring release system that is commonly used in parachutes. The advantage of this design is that the tension is not applied directly onto the release pin. Instead, only a small amount of force is needed to pull the release pin free.
After considerations, we decided to combine the 2 basic designs for our final prototype, selecting .
Prototype
Final Product
Final Product images/videos with descriptions.