Preliminary Detailed Design
Team Vision for Preliminary Detailed Design PhasePLANS FOR PHASE III
Proof of Concept
- Full hardware selection
- Respective beginning stages of analysis
- Begin drafting test plans and design for testing
- Power validation for all components
- Create Bill of Materials and maintain budget
- Redefine software diagram and create timeline for creation
- Create first iteration of attachment to be 3D printed
- Interface with personnel on campus to define process and time frame
- Track risks from system design phase
- Assess risks of hardware interfaces and design decisions
- Develop process to close all risks
- Develop all testing plans
- Create all software for system
- Order all necessary hardware
- Meet with subject matter experts to review design (heat transfer, general drone use, transmission, etc.)
- Selected transmitters, batteries, camera, VR headset, computer, and drone
- Validate high risk of transmission range and data rate through meeting with SME
- Satisfy power requirements for system
- Create and manage budget
- Develop hardware component to be 3D printed
- Began development of test plans
- Update risks and risk mitigation plans
- Develop timeline for finalizing detailed design
Feasibility: Data Throughput
We want to transmit 4K video live from the Ricoh Theta V to the base station. According to the Ricoh Theta V specifications listed on the Ricoh website, the Ricoh Theta V livestreams H.264 encoded 39 FPS 4K video at 120 Mbps (megabits per second) using the USB cable. We intend to use this interface method for our application.
Between the radio transmitter we intend to use and the Ricoh Theta V sits a USB OTG to ethernet adapter. This is required to livestream video using the Ricoh Theta V’s Android based “plugin” system, since no developers seem to have been able to get access to the USB host controls on the Ricoh Theta V. This adapter makes the USB connection appear to be an ethernet connection to the Android operating system on the Ricoh Theta V. USB OTG is a USB 2.0 based connection standard. While USB 2.0 had a theoretical 480 Mbps throughput, in real world scenarios (as a result of bus access constraints) USB 2.0 speeds are closer to 280 Mbps. At half of the expected USB 2.0 throughput, we should still be able to transmit our 120 Mbps video stream. The ethernet cable from the ethernet adapter is then connected directly to the radio transmitter.
We intend to use a PtP (point to point) WiFi / radio connection to stream our encoded video from the drone to the base station. We intend to use the Ubiquiti Nanostation 5AC as the transmitter mounted on the drone. According to the NanoStation 5AC specifications listed in the User Guide the NanoStation 5AC has a realistic throughput of 450 Mbps, and a range of 15 km when using the highest frequencies and 256 QAM modulation. The NanoStation was selected as the transmitter since it has a relatively large receiving cone, suitable for the vibrations on a UAV platform. If the built in antenna underperforms, we could always purchase a high gain, omni-directional antenna for the transmitter.
On the ground station we intend to complete the PtP link using a NanoBeam 5AC Gen2. According to the specifications in the User Guide, the NanoBeam 5AC Gen2 has a range of 15 km and a throughput of 450 Mbps. Compared to the NanoStation 5AC, it has a narrower FOV. This is fine for a ground-based receiver since we can accurately aim the NanoBeam and don’t need to worry about vibrations.
Even at half of Ubiquiti’s “real world” throughput of 450 Mbps, there should be no throughput issues transmitting the Ricoh Theta V’s 120 Mbps 4K video feed. The 120 Mbps video is fed through the USB to ethernet adapter to the NanoStation, which can reportedly beam data 15 km at 450 Mpbs. Then at the base station the NanoBeam communicates with the NanoStation, and has similar specifications. Our engineering requirements only require us to transmit our video 0.25 miles, or 0.4 km, which should allow our throughput to approach the advertised NanoStation / NanoBeam throughput rates. The caveats are there may be issues regarding range and signal quality given the test environment and the alignment of the NanoBeam and NanoStation. Fortunately these issues can be alleviated by purchasing new antennas and by consulting SMEs.
Feasibility: Heat Transfer
It becomes apparent with so much equipment operating on-board our drone, temperature may become a hazard. To better understand this, we set up a lumped capacitance model to understand the expected temperature gradient. The materials used are general solid plastic for the camera and ABS plastic for the casing.
In the next phase, this model will be reviewed with Dr. Stevens, a subject matter expert in Heat Transfer at RIT.
The current MATLAB code can be found here: Heat Transfer Analysis.
Feasibility: Weight Analysis
To track the payload we are adding to our drone as well as the overall weight, a chart containing the mass of every component on the drone was developed. This allows us to see a conservative estimate of the total weight of our drone, and ensure that it does not exceed the maximum payload specification of our chosen drone.
Feasibility: Mounting Bolt Calculations
The mounting holes on the DJI S900 drone that we purchased are M1.6x35. Due to the small size of these bolts, it was relevant to perform calculations to ensure they do not fail under shear stress during the worst case flying conditions. After conducting the calculations, it was discovered that the bolts will not fail under the worst case loading by a very large margin.
To thoroughly document all of the hardware that we will be using for this project, drawings for each piece of equipment have been made. These drawings document important specifications for each item as well as give a visual representation of the parts that will be used.
- For the transmitter and receiver recommended from SME Professor Indovina.
- Low price, high power laptop that is an "Oculus Ready" computer
Bill of Material (BOM)
Design and Flowcharts
The current state of Risks from phase II and III can be found here: Live Risk Management.
- Contact subject matter experts (SME) early in decision process
- Budget more time for feasibility studies and calculations
- Better accomplish deadlines and maintain schedule
- Maintain updates following meetings for action items prior to next meeting
- Better understand all external commitments to distribute work-scope
Plans for next phaseThe plan for Phase IV (Detailed Design) is outlined in Microsoft Project as shown below. High level objectives are as follows:
- Order all hardware
- Prototype attachment
- Appropriate hardware level testing
- Develop software