@@ -193,13 +194,6 @@ Use better and more reliable motors. Improve the opening angle and the locking p
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## Electrical Design (@stlerohss)
## Electrical Design (@stlerohss)
### Design Philosophy
Due to the project’s tight timeline, we were only able to design and order a single version of the PCB, which ruled out an iterative development approach.
Furthermore, the PCB design had to be finalized before the completion of the final mechanical layout, and we also could not wait for the final software implementation for apogee detection.
To best accommodate these constraints, we adopted a forward-compatible and flexible design strategy, ensuring that the PCB could integrate with evolving mechanical and software components without requiring major redesigns.
### Requirements
### Requirements
**Dimensions and Weight**
**Dimensions and Weight**
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The hardware must support a wide range of apogee detection algorithms and software implementations without requiring hardware modifications.
The hardware must support a wide range of apogee detection algorithms and software implementations without requiring hardware modifications.
**Adaptablility towards Mechanical Design**
**Adaptability towards Mechanical Design**
The hardware should be able to integrate with various mechanical designs without PCB redesigns.
The hardware should be able to integrate with various mechanical designs without PCB redesigns.
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@@ -226,61 +220,61 @@ The hardware must remain within the budget.
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**Starting Point**
**Starting Point**
The DLA used a custom Rocket PCB in previous Prjects therfore it was the foundation to be expandaed apon with additional functionality for this Project.
The DLA used a custom Rocket PCB in previous projects therefore it was the foundation to be expanded upon with additional functionality for this project.
WE kept the Xiao ESP32C3 as the Micoprocessor, the 10DOF Sensor PCB and the SingleCell LiPo Battery.
We kept the Xiao ESP32C3 as the microprocessor, the 10-DOF Sensor PCB and the single-cell LiPo battery.
The first Design is the most straightforward Solution.
The first design is the most straightforward solution.
While it is simple, not requiring additional Components it only offers 3.3V with a maximum of 750 mA for all electrical Components. While many Servo Motors will run at 3.3V most are rated for 3.8V or above and realy suffer with low torque and relaiability at lower Voltages.
While it is simple, not requiring additional components it only offers 3.3V with a maximum of 750 mA for all electrical components. While many servomotors will run at 3.3V most are rated for 3.8V or above and really suffer with low torque and reliability at lower voltages.
The Second Design Tested was to have a seperate Voltage Supply for the Motors and the rest of the Hardware.
The second design tested was to have a separate voltage supply for the motors and the rest of the hardware.
This failed hower because the Boost Converter and Esp32 would effectivly act as a Voltage Divider dropping the Voltage registered at the battery Protection circuit of the esp32 below the needed 3.2V, even at very low currents.
This failed however because the boost converter and ESP32 would effectively act as a voltage divider dropping the voltage registered at the battery protection circuit of the esp32 below the needed 3.2V, even at very low currents.
The third design tested was utilising a seperate BMS PCB to keep the Battery Voltage at the correct level on for Protection circuit while not beeing limited to the 0.75 A of the ESP32s Voltage regulator.
The third design tested was utilising a separate BMS PCB to keep the battery voltage at the correct level on for protection circuit while not being limited to the 0.75 A of the ESP32s voltage regulator.
While the Design theoretically provided optimal Power for the Motors it had a lot of Components and inefficiencies limiting the actual benefits.
While the design theoretically provided optimal power for the motors it had a lot of components and inefficiencies limiting the actual benefits.
The fourth Desing tested and ultimatly used in the Rocket was a hybrid design where the Motors could be connected to ether the Boosted Voltage or the ESP32 Voltage via a jumper.
The fourth design tested and ultimately used in the rocket was a hybrid design where the motors could be connected to either the boosted voltage or the ESP32 voltage via a jumper.
During testing we noticed that while the mechanical Power correlated to the electical Power provided the maximum Torque of the Moter was purly related to the supplyed Voltage.
During testing we noticed that while the mechanical power correlated to the electrical power provided the maximum torque of the motor was purely related to the supplied voltage.
The hybrid Design offerd maximum flexibility where the Servo Motor could ether be optimized for Torque by boosting the Voltage or optimized for optimal Power/Efficency using the ESP32 3.3V supply.
The hybrid design offered maximum flexibility where the servo motor could either be optimized for torque by boosting the voltage or optimized for optimal power/efficiency using the ESP32 3.3V supply.
The PCB was screwed into the Bottom Cargo Section leaving the Periphery accessible with a with hole to equalise the pressure for the barometer.
The PCB was screwed into the Bottom Cargo Section leaving the periphery accessible with a hole to equalize the pressure for the barometer.
## Testing
## Testing
During Testing we found that overcoming the friction of the linear Servo Motors and Hinges was the limiting Factor.
During testing we found that overcoming the friction of the linear servo motors and hinges was the limiting factor.
Therfore the optimal reliability of the Servomotors was reached when the voltage was boosted to 4.3V providing maximum Torque without dropping below 3.3V on the ESP32 during stall current.
Therefore the optimal reliability of the servomotors was reached when the voltage was boosted to 4.3V providing maximum torque without dropping below 3.3V on the ESP32 during stall current.
Additionaly lubrication with silicon greace helped tremendously.
Additionally lubrication with silicone grease helped tremendously.
## Launch Day
## Launch Day
On Launch Day one of the Servomotors provided significantly lower Torque and was therefore not able to reliably push one side of the Fairing open.
On Launch Day one of the servomotors provided significantly lower torque and was therefore not able to reliably push one side of the Fairing open.
This was ether because we transported the upper section fully assembled with most of the loads aplyed transfered into the motor or due to the greece of the silicon greece drying up which was applied during the extensive testing on the day before.
This was most likley because the upper section was transported fully assembled with most of the loads applied transfered into the motor or due to the silicone grease drying up which had been applied during the extensive testing on the day before.
However, the spring force of the packed parachute, combined with the second servo motor, successfully opened both sides of the fairing at apogee, allowing the satellite to deploy successfully.
## Software Design (@stsuyooo)
## Software Design (@stsuyooo)
To keep it simple an illustration of the state machine will be used to explain the software. To see the full code visit the project [repository](https://code.fbi.h-da.de/hda10343/dla/-/tree/Satellite/Satellite?ref_type=heads).
To keep it simple an illustration of the state machine will be used to explain the software. To see the full code visit the project [repository](https://code.fbi.h-da.de/hda10343/dla/-/tree/Satellite/Satellite?ref_type=heads).
