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+SOFTWARE ENGINEERING DEPARTMENT
+
+SITUATION REPORT 3
+
+Implementing a Parachute Launching System using Pixhawk
+
+Luís Jesus
+
+October, 2022
+
+Summary
+=======
+
+With this report, I want to introduce a way to implement our Parachute
+Recovery System that will guarantee that the rocket lands on the ground
+successfully. This implementation was suggested by Professor Anuj Regmi
+(SYSTEC). Even though there are not rocketry implementations of its
+suggestion (besides BPS.space) in which we can rely on, it is relevant
+to search how it could be done and some of its constraints.
+
+As concluded in the previous meeting, designing our own board computer
+"from scratch\" is actually very risky and may lead to difficult
+challenges that we may not be able to solve "in-time\", which means that
+we must choose a more reliable path, at least for now. The suggestion
+was to use a Pixhawk Autopilot Board - Pixhawk \[[full specifications'
+sheet
+here](https://docs.px4.io/main/en/flight_controller/pixhawk4.html)\] -
+and ArduPilot as the controller/receiver of this board (it is tipically
+the software used along with Pixhawk).
+
+If we move on to this solution, that means that a great part of the plan
+made by the Electrical Engineering Department will have to be discarded,
+as Pixhawk4 has in-built sensors and they won't have to face the
+expected assembly and testing procedure that was initially designed.
+
+Introduction
+============
+
+Ardupilot is a open source autopilot system that supports many vehicle
+types, such as multi-copters, traditional helicopters, fixed wing
+aircraft, etc. However, there is not much information about its
+implementation in rockets, and the only example we have is
+[BPS.SPACE](https://bps.space/), from which we don't have many
+information.
+
+Considering this, we know that this implementation would need some
+adjustments to fit in the rocketry field.
+
+Mission Planner is part of ArduPilot and it has the interface that
+allows us to follow the vehicle during its flight. However, if we look
+to the picture bellow, we can also see that there is not compatibility
+with a rocket-type vehicle. A amateur SpaceX inspired rocket ([see
+here](https://hackaday.io/project/174329-spacex-inspired-edf-rocket))
+actually implemented Pixhawk running with ArduPilot V4.0.4 configured as
+a single-copter, however, the mentioned project is very different. It's
+not a real rocket; it \"flies\" like a drone, it does not reach high
+altitude, it is remote controlled, etc. The analysis about the
+requirements to make a Pixhawk based board fit a rocket model is in
+charge of our team member João Gil, though.
+
+Considering this, there is not information about parachute deployment
+using Pixhawk + Ardupilot on rocketry, but we can see a more \"typical\"
+case (for example, how it is used in drones).
+
+![image](assets/missionplanner.png){width="\\textwidth"}
+
+Parachute Deployment System
+===========================
+
+As a baseline requirement to implement this, we have, of course, a
+complete parachute mechanism like [SkyCat](https://www.skycat.pro/shop/)
+or [CAD Drones](http://store.caddrones.com/products) but adapted, in
+this case, to fit our own vehicle that is way larger than the vehicles
+Ardupilot is meant for. This study is certainly under the analysis of
+another department, as it is not related to software.
+
+The release of the parachute is actually a mechanical \"phenomenon\" and
+that made the interpretation of the documentation a little bit hard.
+Maybe we need the help of a member of the Electrical and Mechanical
+Departments to help us understanding what is actually happening during
+the deployment of the parachute.
+
+The parachute release mechanism can be triggered from either a Relay or
+a PWM (Pulse-width modulation) signal. If a Relay pin is used, the
+parachute release has to be activated on a high level and RELAY\_DEFAULT
+has to be OFF or No Change, in order to avoid triggering the release
+during initialization. For more information about this and other
+parameters, see [Complete Parameter
+List](https://ardupilot.org/plane/docs/parameters.html#relay-default)
+(we need the help of other departments to better understand them).
+
+We may want the parachute to deploy automatically or manually, but in
+our case, it's just going to be automatic because the Ground Station is
+not sending any kind of signals/data/information to the rocket, it will
+only work as a receiver.
+
+In the [official documentation of
+ArduPilot](https://ardupilot.org/copter/docs/common-parachute.html), it
+is referred that the configuration is made via Mission Planner and we
+have a bunch of parameters to deal with according to our needs and
+specificities. There is some information about the PINs configuration,
+however, I did not understand how our rocket is in terms of mechanical
+components in order to make a detailed report about the implementation
+of this functionality. Considering this noticeable trouble on
+understanding other technical information in the documentation, we may
+need to establish a very close relationship with other departments
+because there are many subjects crossing our theoretical implementation.
+This terms and configurations are important to discuss with other
+departments:
+
+![image](assets/mpsetup.png){width="\\textwidth"}
+
+Apart from this, there is a project called
+[ArduRocket](https://diydrones.com/forum/topics/ardurocket?xg_source=activity)
+that seems to be a modified version of ArduPilot but it is quite old
+(check [GitHub repository](https://github.com/stew-lilley/ArduRocket)).
+
+Veredict
+========
+
+There is basically no information about Pixhawk + Ardupilot usage in
+rocketry, but only about their typical implementations in other
+vehicles. This means that there is a need to study the best way to make
+this type of implementation compatible.
+
+For this, it seems that the help and monitoring of other departments
+(Electrical and/or Mechanical ?) is crucial to understand the viability
+of the implementation. Invictus is being designed to reach an apogee of
+3000 meters and it uses hybrid-propulsion; it seems quite complex when
+compared to those simple vehicles supported by ArduPilot which means
+that there is a big analysis of viability to be made by a competent
+department before any kind of analysis of implementation.
+
+Apart from this, if the transposition of this technology to our rocket
+is achievable and viable, there is the official documentation mentioned
+in this report about the setup of the parachute deployment system, that
+has to be analyzed carefully not only by our department, but
+fundamentally with the help of the Mechanical Engineering Department and
+Electrical Engineering Department.
+
+References
+==========
+
+\[1\] [ArduPilot](https://ardupilot.org/);
+
+\[2\] [ArduRocket (DIY DRONES
+Forum](https://diydrones.com/forum/topics/ardurocket?xg_source=activity);
+
+\[3\] [ArduRocket GitHub
+repository](https://github.com/stew-lilley/ArduRocket);
+
+\[4\]
+[Hackaday](https://hackaday.io/project/174329-spacex-inspired-edf-rocket).