United States Out-of-Water Test Methods to Accelerate Implementation of Autonomous Rendezvous in the NPS ARIES AUV CAPT J.W. Nicholson, Ph.D. United States
Development: Server Vehicle Rendezvous 350 300 250 Target, 1 m/s Pursuit, 1.2 m/s Prop Nav, 1.2 m/s Direct, 1 m/s Meters North 200 150 100 50 0 Chaser Initial Position Target Initial Position -50 0 50 100 150 200 250 300 350 400 450 500 550 Meters East
Challenges (As Always) Significant software changes requiring Significant debugging Limited time, money, in-water opportunities
ARIES Software Modifications ARIES Main Control Loop (8 Hz) Execution Process (RExec) Finite State Machine - Monitor/initiate comms - Mission sequencing - Initiate planning - Initiate replanning - Initiate activation Queue Manager Function Rdvz Queue Mission Activation Function Active Mission RExec Shared Memory Modem Shared Memory Proxy Trigger Planning Shared Memory Rdvz Mission File (RdvzTrack.out) Loiter Mission File (Track.out) Modem Process (Rfm) Acoustic Modem Mission Planning Process (RPlan) Target Target Mission Target Mission Target Data Mission Data Mission Data Data Existing functions Terminate Mission File (TerminateTrack.out)
ARIES State Machine Rdvz comms complete (CC) Loiter Track.out Rdvz in queue Mission infeasible Plan Msn Mission feasible New target posit / GPS fix / Replanning timeout Closing RdvzTrack.out Arrival Init Rdvz Comms Start Timeout Comms Start (CS) Rdvz Query Posit Timeout New target posit Query Posit Mission timeout Terminate TerminateTrack.out
ARIES Control Architecture STATE MACHINE (Strategic Level) MISSION CONTROL (Tactical Level) AUTOPILOTS (Execution Level)
Solution: Laboratory Test Program Hardware-in-loop software development / debugging Install the capability to run missions in laboratory (dry) Benefits Time efficient Cheap Enhanced ability to monitor vehicle operation Shortened run-debug cycle Barriers Vehicle protective functions (abort signals: prop speed, minimum altitude) Risk of equipment damage, inadvertent loss of protective functions Providing simulated sensor inputs
Overcoming the Barriers to Lab Testing Control all modifications with a common, reliably set and cleared signal Block unnecessary protective signals Reduce prop speed by factor of 10 Inject simulated X-Y position and GPS reception data
Original ARIES Software Architecture FreeWave Login Mission Script File Exec 8 Hz Exec Rec SM Modified zone Exec SM fm SM QNXE QeR 16 Hz Way Point File QNXT 10Base2 Ethernet Connection fm (Acoustic Modem) Asynch. QtS 16 Hz Nav 8 Hz Nav SM Bob II (Video Overlay) 1 Hz Indicates Direction of Data Flow BOB SM RDI SM Mot Pak SM GPS SM Analog SM HMR SM RDI (Vel / Alt) ~2 Hz MotPak (IMU) 8 Hz GPS 1 Hz Analog (Depth, etc) 8 Hz HMR (Compass) ~7 Hz
Initial (Stand-alone) Software Testing Acoustic modem Minor modification of existing software and shared memory Test on ARIES using actual modem software / hardware / inputs State machine and queue manager function Logic intensive operations, but little math Exhaustive testing of inputs versus states Embed into existing function (Exec.c) PC (MATLAB), translate into C on ARIES Mission planning module Math / optimization / shared memory intensive Could develop on PC, but translation to C and integration in ARIES would involve a second round of significant debugging ARIES (C)
Integrated Software Testing Set-up 1050 1000 1 0 950 2 3 900 5 4 850 Target Track and Way Points 6 7 Meters North 800 750 9 10 11 8 700 13 12 650 600 550 ARIES Loiter For In-Water Runs Start Point for Laboratory Runs 500 200 300 400 500 600 700 800 Meters East
Time-Optimal In-Lab Track Meters North 950 900 850 800 5 Rendezvous Point (900,500.9) Programming ARIES rendezvous behavior Target Position at Request (900,664) Start Final Course / Speed Change (881.5,515.1) Finite state machine representation of rendezvous process 4 750 700 End of Initial Course / Speed Change (703.3, 501.5) ARIES Initial Position (690,500) 650 350 400 450 500 550 600 650 700 Meters East
Replanned Time-Optimal Track 950 900 5 Final Rendezvous Point (900.0, 490.3) Original Rendezvous Point (900.0,500.9) 4 Meters North 850 800 750 Start Final Course / Speed Change (881.8,504.8) Programming ARIES rendezvous behavior ARIES Expected Position (759.1, 505.7) ARIES GPS Position (750,500) 700 650 400 450 500 550 600 650 700 Meters East
First In-water Run: Time-optimal Rendezvous 1000 950 Target Position at Request 1 2 Rendezvous 0 3 Target Track 900 5 4 Programming ARIES Replan rendezvous behavior 850 800 750 700 Finite state machine representation of rendezvous process Closing Return to Loiter 650 600 ARIES Loiter 550 200 300 400 500 600 700
Summary Significant savings in time / effort / money Several hundred runs, in days (vice months) Enhanced fault diagnosis, rapid correction Simulated sensor inputs need not be complete set, or high fidelity (judgment / trade-offs) Care in blocking / restoring / retesting abort and other protective functions Power down unnecessary vehicle components to avoid wear and tear (nav / comms equipment) Nominal performance first time in the water
Questions CAPT Jack Nicholson, USN United States jnichols@usna.edu
Back-up Slides
RENDEZVOUS SHARED MEMORY RExec Shared Memory Rfm Shared Memory Outgoing Message Flag Outgoing Message ARIES X Coordinate ARIES Y Coordinate ARIES Course Read by Rfm Read by RExec New Data Flag Message Command Target Number Way Point Progress ARIES Speed Time Stamp Set Drift Optimization Objective/Check Sum Current Target Number Current Way Point Current Progress Current Time Stamp Current Optimization Objective/Check Sum Clock Time Read by RPlan Read by RExec RPlan Shared Memory Proxy ID Plan Ready Flag Plan Feasible Flag
Target Vehicle RENDEZVOUS TRAJECTORY Rendezvous Point (X 3,Y 3 ) (X 2,Y 2 ) GPS Fix Final Course/Speed Change (X 1,Y 1 ) (X i,y i ) Initial Course/Speed Change ARIES
ADVANCE, TRANSFER AND PATH LENGTH Start Turn Advance Transfer Parameterization of turn characteristics 50 Turn Complete 45 40 35 Advance Transfer Path Length 30 Meters 25 Used to compute spatial and temporal turn effects 20 15 10 5 0 0 0.5 1 1.5 2 2.5 3 3.5 Course Change (Radians)
SET OF REACHABLE STATES t=t 1 Target Vehicle Initial Position t=t 2 Earliest Possible Rendezvous Target Track Chaser Vehicle Set of Reachable Positions t=t 1 Chaser Vehicle Set of Reachable Positions t=t 2 Chaser Vehicle Initial Position
TIME-OPTIMAL RENDEZVOUS POINT Target Vehicle Find (X 3,Y 3 ) such that distance = u max x(t 2 -t 1 ) (X 1,Y 1,t 1 ) (X i,y i ) (X 2,Y 2, t 2 ) Initial Course/Speed Change ARIES Rendezvous Point (X 3,Y 3 ) Final Course/Speed Change
ENERGY-OPTIMAL RENDEZVOUS POINT Target Vehicle Refine u such that distance = u(t 2 -t 1 ) (X 1,Y 1,t 1 ) (X 2,Y 2, t 2 ) Sampled Rendezvous Points (X 3,Y 3 ) Minimum Energy Rendezvous Point (X i,y i ) ARIES
IN-LAB RUNS Rendezvous request: RVS,REQ,0,5,120,30,+/-155
ENERGY-OPTIMAL IN-LAB TRACK 950 900 Candidate Rendezvous Points 5 Target Position at Request (900,664) 4 850 Rendezvous Point (900,420) Meters North 800 Target Target Way Point ARIES 750 700 ARIES Initial Position (690,500) 650 400 450 500 550 600 650 700 Meters East
ENERGY-OPTIMAL CALCULATIONS 9 x 104 8.8 8.6 8.4 Energy (Joules) 8.2 8 7.8 7.6 7.4 7.2 7 400 410 420 430 440 450 460 470 480 490 500 Candidate Rendezvous Y Coordinate
CONTROLS AND STATES 2 Rendezvous Request Rendezvous Heading (deg) Rudder (deg) u (m/s) u com (m/s) 1.5 1 0.5 650 700 750 800 850 900 950 2 1.5 Programming ARIES rendezvous behavior Finite state machine representation of rendezvous process 1 650 700 750 800 850 900 950 20 0-20 650 700 750 800 850 900 950 100 50 0 650 700 750 800 850 900 950 Time (sec)
ENERGY-OPTIMAL IN-WATER TRACK 900 850 800 750 700 Programming ARIES rendezvous 9 behavior Replan Target Track Target Position at Request 6 7 Finite state machine representation of rendezvous process 8 Candidate Rendezvous Points Closing 650 600 ARIES Loiter 550 500 250 300 350 400 450 500 550 600 650 700 750
WORK TO BE DONE MAGNETIC SWITCH PANEL DEPTH CELL TRANSDUCER BOW SECTION LEAK DETECTOR VIDEO CAMERA RDI DOPPLER SONAR BENTHOS ACOUSTIC MODEM DIGITAL VIDEO RECORDER HONEYWELL HMR3000 COMPASS MODULE SYSTRON-DONNER MOTION PAK IMU FORWARD BALLAST TANK DUAL QNX PENTIUM COMPUTERS + CONTROL BOARDS + HARD DRIVES +DC/DC POWER SUPPLIES AFT BALLAST TANK CISCO WIRELESS LAN/AMPLIFIER ASHTEC GPS RECEIVER STERN SECTION LEAK DETECTOR WIRELESS LAN ANTENNA DC/DC POWER SUPPLIES 2 TECHNADYNE MODEL 520 THRUSTERS) KEARFOTT RATE GYRO BENTHOS MODEM ELECTRONICS BOB II VIDEO CARD PC104 SENSOR PROCESSOR 12 VOLT BATTERY (6) MID SECTION LEAK DETECTOR DC/DC POWER SUPPLIES MAIN POWER RELAY CURRENT SENSOR MULTI-PURPOSE ANTENNA FREEWAVE RADIO VEHICLE TO SHORE COMM. LINK FREEWAVE RADIO DGPS LINK GPS ANTENNA FIN SERVO (6) THRUSTER CONTROL BOARD Configuration: May 2004