1 Jillian Redfern Orbital Express Presentation TITAN All-Hands 07/08/2003

2 Topics to be Discussed Orbital Express and Mission Manager TITAN’s role Progress Future work Suggestions

3 DARPA’s Motivation

4 Movie of Robotic Arm

5 Movie of Direct Capture

6 Program Plans Develop and validate software for autonomous mission planning, rendezvous, proximity operations and docking. Design, fabricate, and test on-orbit robotic satellite servicing, including fuel and electronics transfer, deployment of and operations with a micro-satellite. Design, fabricate, and test on orbit a modular micro- satellite for protection of stationary satellites. Perform utility assessments of on-orbit servicing in conjunction with operational customers and plan for technology transition.

7 Main Operations –Guidance, Navigation, & Control –Capture Free Fly Capture (With Robotic Arm) Direct Capture (With Grappling Mechanism) –ORU Transfer NextSat to ASTRO (With Robotic Arm) ASTRO to NextSat (With Robotic Arm) –Fluid Transfer NextSat to ASTRO ASTRO to NextSat –Mission Manager (Draper Lab’s part)

8 Failure Concerns Top 12 Failures Which Require Autonomous Response Fail to direct capture Fail to free-flyer capture AC1 fault which results in reboot AC2 fault which results in reboot AVGS fails during prox ops MCU fail during arm use Battery DOD above 75 (TBR) % Fluid coupler fails to engage Fluid coupler fails to disengage Pump fails on RCS jet fail during prox ops Selected valves fail open or closed

9 Draper’s Mission Manager Draper’s Mission Manager “looks” a lot like TITAN at the high levels Current thinking for fault diagnosis: –rule-based -- system engineer generated fault response system which is pre-determined (simplifies Diagnosis and Planning step through database utilization) I want to add in a Diagnosis step through either TITAN or MINI-ME

10 MM Executive Database Monitor Sequencer NEXTSatOEDMSAutoGdAutoNavCMFTAPSASTRO Commands Resource Predictor Contingency Responder Response Messages Mission Manager

11 TITAN Model-based Program Titan Model-based Executive Sequencer Deductive Controller Control Program Plant Model Configuration goals State estimates Physical Plant Flight Control Software Control actionsObservations Mode Reconfiguration Mode Estimation Activity goals (from planner) CCAs

12 FTAPS Modeling (What Jillian has been up to)

13 System (Extremely simplified) 2 Valves (not pyro) 2 Fluid Transfer Tanks 1 Pump 1 Pressure Sensor 2 Flow Sensor Flow in both directions *Assume valves open individually Tank1Tank2 Valve2 Valve1 Pump F2 F1 P1

14 Fluid Transfer Tank Level (Tank1) Broken Filling/Emptying Empty Full (P1 = Nominal) (P1 = Low) (P1 = High) Pump = 1to2 Pump = 2to1 Pump = 1to2 Pump = Off

15 Fluid Transfer Tank Level (Tank2) Broken Filling/Emptying Empty Full (P1 = Nominal) (P1 = High) (P1 = Low) Pump=Off Pump = 1to2 Pump = 2to1 Pump = 1to2

16 Propellant Isolation Valve Number 1 Unknown Open Closed Leaking Cmd=OpenV1 Cmd=CloseV1 F1 = reverse F1 = stagnant F1 = forward

17 Propellant Isolation Valve Number 2 Unknown Open Closed Leaking Cmd=OpenV2 Cmd=CloseV2 F2 = stagnant F2 = reverse F2 = forward

18 Pump Broken 1to2 Off Cmd=PumpOff (NOT Valve2=open) OR (Valve2=open AND F2=forward) (F1 = Stagnant) AND (F2 = Stagnant) 2to1 (NOT Valve1=open) OR (Valve1=open AND F1=forward) Cmd=PumpOff Cmd=PumpRight Cmd = PumpLeft

19 Initial State Pump = Off V1 = Closed V2 = Closed Tank1Level = Full Tank2Level = Empty Pressure = High Flow1 = Stagnant Flow2 = Stagnant

20 Nominal Scenarios When Tank1Level = Full, turn pump on right and open valve V1 and close valve V2 When Tank1Level = Empty, turn pump off and close valve V1 and open valve V2. Turn the pump on left.

21 Off-Nominal Scenario At t = 1 –Pump = Off –Flow1 = Stagnant –Flow2 = Stagnant –V1 = Closed –V2 = Closed –Tank1Level = Empty –Tank2Level = Full –Pressure = Low At t = 2 –Valve2_Command = open –Pump_Command = PumpLeft At t = 3 –Pump = 2to1 –Flow1 = Reverse –Flow2 = Forward –V1 = Closed –V2 = Open –Tank1Level = Filling –Tank2Level = Filling –Pressure = Nominal At t = 4 –Valve1 = Leaking (Can I think of this as a fail to close?)

22 Another Off-Nominal Scenario At t = 1 –Pump = 1to2 –Flow1 = Forward –Flow2 = Stagnant –V1 = Open –V2 = Closed –Tank1Level = Filling –Tank2Level = Filling –Pressure = Nominal At t = 2 –Pump_Command = Off At t = 3 –Pump = Off –Flow1 = Forward –Flow2 = Stagnant –V1 = Open –V2 = Closed –Tank1Level = Filling –Tank2Level = Filling –Pressure = Nominal At t = 4 –Pump = Broken

23 Failure Probabilities Valve1 – equal probability of failure Valve2 – equal probability of failure Pump – higher probability of failure Tank1 – low probability of failure Tank2 – low probability of failure

24 Progress Extremely simple model has just now been compiled successfully I have not run the mof file through TITAN or even Mode Estimation

25 Goals for Thesis/Project Model the rest of the system accurately –FTAPS –Capture Direct Free-Flyer –ORU Transfer Adapt TITAN/MINI-ME to my needs or at least demonstrate its diagnosis is better than a system engineer Help improve the utility of TITAN to other programs

26 My questions to the group The monitor: I receive a lot of status updates from software and general system statuses. What can I do with those? Do I always assume the commands are getting to the correct components? Not sure whether I have hybrid capabilities with the monitor Is there someone who is a better modeler than I in this group? Why do we code it like this: (off :documentation "The OFF mode." :model (and (= (flow ?valveName1) stagnant) (= (flow ?valveName2) stagnant) (= (pump_mode ?pumpName) off))