Competition | 2023-2024 Aerial Evolution of Canada Student Competition | ||||||
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Team | Waterloo Aerial Robotics Group | ||||||
Technical Director | |||||||
Version | Document Version
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Min | Recc/Avg | Max | |
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Propeller Diameter (in) | 20 | 22 | 24 |
Battery Voltage (v) | 36 | - | 50.4 |
Takeoff Weight | 4.5 | < | 8 |
Thrust (kg) | ~16 | ||
Flight time (min) | 30 | TBD (40?) | |
Wind Lim. (kt) | < 20 | TBD (< 60) | |
Altitude (m) | < 120 | 200 | |
Horizontal Pos Accuracy (cm) | +/- 2 | +/-30 | +/- 200 |
Vertical Pos Accuracy (cm) | +/- 2 | +/- 15 | +/- 30 |
Usable Range (km) | 1 | 10 | inf w/LTE |
Airframe
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Pegasus is an X-frame configuration and motor arms attached directly to a straight aluminum block. Here are some of the key notes:
30x30mm mounting grid for peripheral and accessory mounting
Xmm 1.25mm thick mainplates
Xmm 76.2mm distance between mainplates
225 mm 422mm plate width (flat edge to flat edge)
Xcm 1.19m distance motor to motor
Xcm dimensions 1.80m tip-to-tip with props on
Xmm 20mm high spacer for the autopilot
Top & Bottom Plates
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Mech should probably fill this out a bit more |
<pegasus rendering>
< more information & dimensioning if necessary >
Top & Bottom Plates
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Mech should probably fill this out a bit more |
Featuring 30x30 mm blocksFeaturing 30x30mm pattern of holes on the majority of the surface with rounded square lightening holes, these plates provide torsional rigidity and protection for batteries within the drone. They are < more information here >. These are Xmm thick, and made with <material>. FILESapproximately 1.25mm thick, but the thickness across the sheets varies due to manufacturing imperfections. The plates were first made with custom carbon fiber flat layups, and were then cut out on the CNC router.
Center Block & Inner area
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The center block is where all 4 arms connect, and how the arms remain rigid and centered on the drone frame. It is made of <material> and uses <screws> to disconnect. Shoulder bolts are used <somewhere> to improve <something>consists or one aluminum square block in the middle with a large hole in the middle for wire routing and weight saving as well as 4 arm connector pieces. These bolt onto the center block using 4xM5 bolts and they have an OD that fits snugly in the ID of the carbon fiber arm tubes. The plates and standoffs are attached to the center block using M3 screws. It is designed for easy removal of the arms for transport, if necessary.
< Link to supporting documentation/CAD>
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Interfacing
The center block and arms are designed to allow 3-phase motor wires to run through the arms and exit out the cube below the pixhawk or otherwise <drawings here would help>.
MT30’s are designed to fit within the cube and arms for quick-disconnect of the 3-phase leads. See connector standardization for more information.
Removing the arms
Instructions for how to remove the arms, diagrams if possible.
Arms & Landing gear
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| panelIconId | 1f527 |
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| panelIcon | :wrench: |
| panelIconText | 🔧 |
| bgColor | #ABF5D1 |
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To remove the arms, the bolts on the top and bottom of the arm connectors need to be removed. After this, the arms can be slid off the arm connectors, the MT30 can be disconnected, and the arm is ready to be fully removed.
Arms & Landing gear
The arms mount to the airframe at the center block, and also through the spacers located at each corner of the frame. The landing gear mounts directly to the arms.
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Payload attachment points
Inofrmation about how exposed slots in the frame allows for payload attachment points and best practices for that
Motor Mounting
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Two slots per arm have been left in the plate to accommodate payload mounting and any other necessary additions to the aircraft. The slots are designed to give sufficient clearance for members extruding downwards from the frame, and space to access any connectors on the top of the tubes to mount and dismount payloads.
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Motor Mounting
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Mech should probably fill this out a bit more |
Motors are mounted on 3d printed mounts with a <pattern> (insert a photo if you can). 32mm M4 bolt circle pattern with 4 evenly spaced bolts. The motor mounts have an indent to relieve wire strain, and minimal material to save weight.
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Electrical Protection
Although not strictly airframe related, avionics covers and cabin covers will be an integral part of the airframe design, and must be well-integrated. The end goal of the system is simple:
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Most components will run ~ 20-30 degrees hotter than ambient, and will thermal limit around 80 degrees celcius. This means that on an average “warm” day, our compoments have around 20-30 degrees of headroom. Think about how much hotter a cabin may cause components to be, especially if black carbon fiber and in the air (exposed, not under shade).
Propulsion
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Electrical, please insert a schematic & layout diagram with motors, connectors, esc’s with breaks to the rest of the HV distribution system |
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Telemetry wires shall be connected to a uart port, in the case of a bidirectional dshot failure. This is significantly slower than bidirectional dshot but offers us a failsafe and backup.
Power Distribution
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On Pegasus, “power distribution” refers to all elements that affect and interact with power before it is distributed to individual components. Typically, this includes:
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DShot is only available on FMU out as of 4.4.0, but will be available (tentatively), on certain I/O FMU Outputs in the future.
Flight Control System
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Pegasus will operate using an ardupilot software stack. As of Fall 2023 Pegasus runs software revision 4.4.0, as this brings necessary changes for digital power monitoring and bidirectional dshot.
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Accelerometer calibration does not need to be done more than the first time you did setup, or if there is significant concern about the health of the system.
RF + Peripherals
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There are a number of external devices on the drone. Autonomy is largely responsible for additional compute, while Electrical is largely responsible for RF
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ok thank you for listening
Change Log
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