Introduction

Summary

• We are taking on a short term project to remove the paper airplanes from the E7 atrium ledges this term.

  • We will not be removing the dust.

  • Project is being taken on with significant coordination from Professor Rayside

    • https://uwaterloo.ca/electrical-computer-engineering/contacts/derek-rayside

• This test will be to validate our engineering solution in a low stakes area.

  • Our solution is blowing the planes away with prop wash from Houston.

  • This is the simplest solution we got and works well on the ground in the SDC.

• There will be a subsequent flight test (not covered by this document) with a different flight plan in which will involve closing off the north section of E7 in addition to the south section to clean the area.

Aircraft Information

• We will be flying a HOUSTON Class Quadcopters.

  • Lidar and rangefinder depopulated.

    • While the readings my be useful these add weight and cost to the system.

  • Weight is just above 1kg w/ battery.

    • Measured at 1.3kg with the prop guards and all

  • GPS will not function due to being indoors and pilots have practiced GPS denied flight.

    • GPS was manually disabled in ardupilot

    • the GPS module was still fitted on the drone so we could use it’s internal compass

  • Flight mode Stabilize or AltHold decided by pilots discretion.

• Sub 250 gram drones may be used as well in this testing if this is deemed as the only permissible option.

  • This was not done.

Known Rules & Regulations

• Transport Canada rules do not apply because flight is indoors.

• https://uwaterloo.ca/safety-office/occupational-health-safety/remotely-piloted-aircraft-systems-drones

• In the SDC only Graeme & Teertstra have informed us tethered flight is permissible without a need to request approval for a specific flight plan.

  • This was discussed a while ago and will be discussed again during F24 term.

Date

• We want to do it before the start of F24.

• We cannot do it on the weekend as plantops is not present.

• Evenings are preferred as E7 will be mostly depopulated.

• Date and time must be approved so this document will remain ambiguous

Members

Participating

• @Daniel Puratich

• @Hardy Yu

Confirmed Unavailable

Unavailable until the first day of F24 term.

• @Smile Khatri

• @Yuchen Lin

Further Information

• See our internal conversation at this discord thread.

• Further context can be found within the WARG Email.

Flight Test Plan

Timing

• Late in the evening or early in the morning is preferred as E7 will be mostly depopulated.

• Testing window should be ~ an hour in length.

  • Targeting 30 minutes of setup time and 30 minutes of flight time max.

Location

• Floorplans

  • https://uwaterloo.ca/plant-operations/floor-plans

  • https://plantops.uwaterloo.ca/floor_plans/pdf_drawings/067E7_01FLR.pdf

  • https://plantops.uwaterloo.ca/floor_plans/pdf_drawings/067E7_02FLR.pdf

• The flight area will be above the 2472 area of E7

  • E7 2472 is commonly known as the E7 event space and is depicted below on the floorplan in red.

  • See the below drawing. We will be flying above the pink/red exclusion zone for this test flight.

  • The area in green can be blocked off or have WARGians nearby to advise people not to enter.

• Flight test team will stand above the drone at all times

  • Flight team will be on a stairway, landing, or bridge in E7/E5 at a higher altitude than the drone at all times.

  • This is both for safety concerns and also to maintain visual contact with the drone for flight control.

  • It’s alright if there are spectators around the pilots during the flight.

Open

Concerns

Safety Controls

Referring to https://www.ccohs.ca/oshanswers/hsprograms/hazard/hierarchy_controls.html

• People will be prevented from going close to the drone.

  • This flight plan involves perimeter control to ensure there are no members of the general public / university community in the flight area so nets and tethers will not be employed.

• Pilots will maintain line of sight with the aircraft at all time.

Liability Controls

• The 7th floor administration is assuming responsibility if the unlikely case of a propeller strike.

Debrief

Open

Houston Aircraft (just prior to flight test at 1.3 kg w/ battery)

Media

• Hardy recorded on his phone.

  • Will be uploaded to our Media Folders (Photos & Videos) | 📝 Media Ingest Folder .

  • Most flights were not recorded, but a few were particularly to document our issues.

• There are some images we took on the ops camera. Won’t bother downloading just yet.

• Daniel took some photos on his phone as well

  • mostly not during flight as was busy piloting

Timeline

• started setting up around 8:50 and finished at around 10pm

• First we went to the stairs between the second and third floor starting the first flight

  • We did not need to do accelerometer or megnetometer calibration in flight.

• Althold flight mode first, noticed some altitude instability during flight

  • This was somewhat predicted due to barometer error and similar behavior was observed outside.

  • Notably the barometer is temperature sensitive.

• Changed to Stabilize flight mode for the rest of the flights

  • eliminated the altitude instability and was controllable due to pilot practice with this more manual throttle mode.

• Disabled compass 1 and enabled compass 2 for determining heading when using 2nd battery

  • The IMU error didn’t get mitigated at all, more compass error noticed after making this change

  • it turns out this magnetometer change doesn’t play an important role in this game

• Noticed IMU drifts after a period of flight, have to land every 5 mins to reset it

  • Sometimes it would automatically reset, we have videos showing this

  • Sometimes a power cycle was required. This was very time consuming with only two people on the flight line.

• Ended up consuming all three batteries

  • Each battery can last for estimably 15 mins of flight time

Wins

• No crashes

  • Prop guards never contacted the wall

• Cleared some debris

• Yaw was very stable

• Throttle was very stable in stabilize flight mode

Issues

IMU Issue

• What was the issue:

  • The drone’s definition of level would drift over time.

• Resulted in

  • Pilotting became more difficult over time as pilot would have to hold a constant stick input to maintain level flight

  • We landed on the ledges accidentally twice when the drone was harder to control .

  • Lots of time having to land on the ground over and over again so the drone could reset it’s definition of level flight

• Possible Solutions (we can test these and may brainstorm more)

  • Installing optical flow sensor.

    • We have these sensors.

    • Was mentionned as a solution in https://discuss.ardupilot.org/t/indoor-flight-horizontal-position-shift-drift-using-only-imu-sensors/94877 .

  • Being able to use controller trim during flight may be able to resolve the issue without landing.

  • Disabling all compasses may help.

  • Changing IMU settings may help.

  • Try FlowHold flight mode which doesn’t need GPS https://discuss.ardupilot.org/t/indoor-flight-horizontal-position-shift-drift-using-only-imu-sensors/94877

  • Do ardupilot configuration following https://ardupilot.org/copter/docs/indoor-flying.html

  • An imu temperature calibration may help https://ardupilot.org/copter/docs/common-imutempcal.html

• Why we didn’t catch this sooner

  • All our other tests were outside and away from large metal obstacles so this condition did not arise as severely as it did.

• What caused it:

  • Flying near the metal walls seemed to cause the center drift to become much more severe.

  • Doing sharp stick inputs when in the middle of the event space did not cause any problems.

  • Flying near the concrete didn’t cause much problems either it seemed.

  • We have videos showing this, maybe review those and don’t trust us so much.

Debris Removal Issue

• Resulted in:

  • The paper airplanes get stuck under the metal piece on the edge of the wall and it means even though we’re blowing them up a bit the nose tip remains still stuck in the crevice.

  • hard to clean the paper airplane on the corner/beside the wall

  • sometimes we blow the paper airplane to those spots as well

• Possible Solutions (we can test these and may brainstorm more of course)

  • propeller direction config such that it sucks objects instead of blow them away?

  • A different approach.

• Why we didn’t catch this sooner

  • This was our simplest possible approach and we weren’t too sure how it would go

    • that is why we have this test flight !!

• What caused it:

  • the propellers blows the stuff outwards

  • It’s tough to get close to the wall to avoid blowing stuff closer to the wall

Next Steps

• Look into issues.

• Email Derek & Dennis to update them of our status.

• Try again on Friday evening for another test flight.