CASCADE Case Study: Scan a Bridge
• Single-operator aerial inspection of the Clifton Suspension Bridge
• Thermal data, workflow and business case
Operational Challenges: Safety and Agility
• GGG
245ft
76ft
331ft
Operational Challenges: Safety and Agility
• Highly complex environment
• Risk mitigations• Exploit road closures
for events and planned maintenance
• Railway rarely used• Bridge Trust and
Bristol City Council supportive
• Tether?
Paths
Railway
Busy roads
Complexity
• Mitigation: use off-the-shelf small (<7kg) multirotor
• DJI * or AscTec Falcon8• Limited on-board complexity
• Congested, complex environment
• Mostly VLOS, some EVLOS
• Category A or B operation• Depends how you judge the
complexity
Research Challenges
• Major goal: single person (E)VLOS operation in complex* environment• “Crew – usually minimum of two. One pilot in command, and one observer/camera
operator. Other missions may require more crew; spotters, engineers, aides and so on.” – Network Rail
• * Means we will not sterilise the area… but maybe it’s quiet and partly controllable
• Approach: on-ground autonomy to mitigate environment complexity• Mission design for safety
• Includes Remote Pilot location, spotting, contingencies, and robust mission execution• Autonomous execution monitoring by Remote Pilot Station
• Concept: autonomous RPA Observer for EVLOS• Simple – low workload – Remote Pilot interface
• Pause / Go / Abort
System Platform Payload
ControllerAutonomous
AssistantMobile
Assistant
Tracking
Area Monitoring
Tracking
Mission Planner
H
Mission Design
• Inputs• CAD model of target structure• Routes of uncontrolled users through
region of interest• Platform and sensor parameters
• Output: robust sequence of segments• E.g. a behaviour tree• Each has safety preconditions
• Battery > X%; Zone Z clear; UAV at W; Remote Pilot at location Y
• System integrity confirmed• Whole mission proven safe
• Contingencies pre-planned
This Photo by Unknown Author is licensed under CC BY-NC-SA
Behaviour
DMS
Blackboard Tasks
States Sensing Dashboard
getPose getTwist getOtherCars approach_warning clear_range Passed car check LR pedestrian check RL pedestrian check RC pedestrian check OC cyclist check Button1_2BB Button2_2BB Button3_2BB Button4_2BB
Laps
Lap 1 Lap 2 Lap 3 Lap 4 Lap 5 Lap 6
drive L1 P1
Drive North -> Steps
Right - Steps - Empty drive L2 P1
Always True Drive Steps -> Steps
Right - Steps - Ped drive L3 P1
road crossing ped Drive Steps -> Steps*
Right - Steps - cyclist drive L4 P1 Left - MOD drive L4 P2
OC car Drive Steps -> MOD Always True* Drive MOD -> HP
Right - HP drive L5 P2 Right - MOD
Always True** Overtake Drive HP -> MOD
Overtake? Overtake?*
Request overtake Overtake right
Overtake Button? clear range check OC car* Passed?
Passed Obstacle CL Right
passed car CL Left
on overtake straight? running_is_failure
passed car*
Request overtake* Overtake right*
Overtake Button?* clear range check* OC car** Passed?*
Passed Obstacle* CL Right*
passed car** CL Left*
on overtake straight?* running_is_failure*
passed car***
Always True***
drive L6 P1 Right - Steps drive L6 P2 Right - HP* drive L6 P3 Zebra Crossing drive L6 P4
Drive Mod -> Steps Always True**** Drive steps -> HP Always True***** Overtake* Drive HP -> crossing
Overtake?**
Request overtake** Passed?**
Overtake Button?** clear range check** Passed Obstacle** CL Right**
passed car**** CL Left**
on overtake straight?** running_is_failure**
passed car*****
crossing ped RL Drive crossing -> North
Nuggets
MAIN STREAM• Mission modelling and design
methods
• Statistical basis for acceptance trials criteria
• SUA platform integration and safety case
• Autonomous Remote Pilot Station
EXTRA SCOPE (PhDs? Creep?)• Autonomous RPA Observer
• Flight design and operations with safety tether
• Ballistic characteristics of standard platforms
• Smartphone-based black box• “Internet of Drones”
Demonstration Milestones
• Following nuclear industry’s“lab / white / red” concept
• Thorough statistical analysis• Acceptance criterion = X hours of
problem-free operation• “Problem” here means an
unhandled circumstance• Manual intervention?
• Quick & dirty demo in Aug 2018
• Lab• Simulation HWIL sim HW at flying site
• Simulated disturbances, failures and passers-by
• White• Real site, but with closures, and
trained participants interacting• Include simulated failures
• Red• Real site, real day
Collaborations
Internal
• Cranfield: formal mission spec
• Manchester: mission & safety
• Southampton: visual tracking
• Imperial: drones & tethers
External
• UK Collaboratorium for Research on Infrastructure and Cities (UKCRIC):
• Value added and payload
• Clifton Suspension Bridge Trust• A bridge!
• Assuring Autonomy (?)
Next Steps
• “Quick and dirty” concept experiment
• August 2018
• Refinement of scope• Payload: UKCRIC• Tech: CASCADE
• Possible aligned PhDs• Sept 2018/19 start
• Target: August 2020
• What’s not in scope?
• Turbulence & poor weather
• Precision proximity control
• Multi-platform operations
• Autonomous flight control
• Dynamic mission re-planning
• 5G connectivity