Design Simulation and Software Validation for Optimal Guidance
Transcript of Design Simulation and Software Validation for Optimal Guidance
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Design Simulation and Software Validation for
On-Board and Real-Time Optimal Guidance
Carlo Alberto Pascucci, Alvaro Fernandez, Juan Jerez, Samir Bennani, Jean-Philippe Preaud, Jorgen Bru
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WHY DO WE NEED REAL-TIME OPTIMAL GUIDANCE?
• Trajectory optimality under actual flight conditions
• Ensure mission completion under constraints and actual flight conditions
• Reduce missionization time
• Mid-flight replanning(mission flexibility)
On-line optimization enables autonomous space operations
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PROJECT TIMELINE
Phase 1Feasibility study
Phase 2.1Maturation and flight test plan
Phase 2.2Flight testing
Constrained Powered Descent
Constrained Attitude Guidance
2016 - 2017 2018 - 2019 2019 - 2020
ESSL
FES
SVFContinuous integration
testing
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MISSION PROFILE
INCAS Demonstrator for Technology Validation: DTV
• Jet powered
• Vertical Takeoff and Landing
• Max thrust = 900N
• Weight = 60 - 70 Kg
• Hight = 1.2 m
1. Vertical takeoff
2. Ascent (Real-Time Optimal Guidance)
3. Descent (Real-Time Optimal Guidance)
4. Vertical landing
End-to-End mission scenario
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GUIDANCE AND CONTROL ARCHITECTURE
Flight mode selector
MVM• Flight mode selector• Target manager• Handle exceptions• Tracking errors• Engine faults• Retargeting• Emergency landing
Guidance• Constant velocity takeoff• 3-DoF NLP optimal• Constant velocity landing
Control• LQR on position and attitude• FF aerodynamics balancing
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OPTIMAL GUIDANCE• Tested strategies
3-DoF convex
3-DoF convex with ToF lookup table
3-DoF non-convex
6-DoF non-convex
Glideslope constraint
Thrust constraints
Minimize fuel consumption
Minimize landing error
or
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OPTIMAL GUIDANCE GUIDANCE
ToFinitial
estimate
NLPFORCES
solver
Enough fuel? Optimal trajectory
NLP minimum landing Error FORCES solver Optimal trajectory
NLP Embotech guidance
ToFinitial
estimate CVX FORCES solver
ToF searchSolution found? Optimal trajectory
Problem infeasibleCVX Embotech guidance
Trajectoryinitial guess
Trajectoryinitial guess
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• A unifying framework designed to extensively evaluate and analyze the guidance and control performance
• Completely modular and extendable architecture
• Matlab/Simulink interface
• Support for automatic code generation and deployment on embedded platforms.
The generated C is embeddable on-board as part of the real-time flight code
SOFTWARE FRAMEWORK
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FORCES PROConcept
• State-of-the-art client/server code generation system for optimization solvers
• C code tailored for deployment on embedded systems
• Uses only static memory allocation
• No dependency on external libraries
• MISRA C compliant
• Wide range of algorithmic options for LPs, QPs, QCQPs, SOCPs, NLPs and MI-NLPs
• Developed and professionally maintained by embotech AG
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FUNCTIONAL ENGINEERING SIMULATOR (DTV)
An expandable simulation library built for INCAS’ DTV
Simulators
Library blocks
Initialization files:• mass
properties• propulsion
system• environment...
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LIBRARY BLOCK EXAMPLE
From initialization files
From utility library
From utility library
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SIMULATION ENVIRONMENTSVehicle and Environment
GNC
Functional Engineering Simulator
Speedgoatstandalone RT
computer
PC/104+ flight computer
ESSL
vehicle simulation
flight software
Simulink coded and compiled on host
Simulink coded and compiled on target
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SIMULATION EXAMPLE
1. Nominal end-to-end mission
2. Mid-flight retargeting
3. Engine fault
4. Wind on ascent
1 2
3 4
• Takeoff pad• Landing pad• Emergency pad
Glideslope
CPU Median [s] Max [s] Min [s]
i7 8550U @ 1.8
0.07 0.15 0.04
Atom E3845 @ 1.9
0.25 0.55 0.19
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SOFTWARE VALIDATION FACILITY
CONTROL COMMANDS
DTV MEASURED STATE
RS232
RS232
ETHERNET ETHERNET
Host Computer Tasks:
• Code generation;
• Code loading into Speedgoat & PC/104+;
• Processes launch;
• Data log recovery;
• Results plotting & analysis.
Key Features:• PC/104+ & Speedgoat connected using two different serial
cables;
• Communication between PC/104+ & Speedgoat at 25 Hz;
• Speedgoat & PC/104+ connected to the local embotech’snetwork via Ethernet;
• Host computer accesses PC/104+ via SSH;
• Host computer accesses Speedgoat via Simulink Real-Time Explorer. Host Computer
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REAL-TIME FLIGHT SOFTWARE
RTO
S s
che
du
lerPERIODIC GNC
OPTIMAL TRAJECTORY GENERATOR
OPTIMAL TRAJECTORY
COMPUTATION DONE FLAG
EN
AB
LE
0.04 [s]
Thread #1. RT priority
Thread #2. Lower priority
Shared Resource
Thread Process
Real-Time Operating System
Input/Output Signal
Read from A
Write to A
A
A
Read from/Write to AA
INIT
IAL
STA
TE
TAR
GE
T S
TATE
0.04 [s]
MEASUREMENTSCONTROL COMMANDS
MISSIONMVM
CONTROLNAVIGATION
REFERENCE GENERATION
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• Functional validation campaign• 2576 scenarios simulated under nominal, robust and fault conditions• Sensitivity analysis w.r.t. noise and dispersion
• Software validation campaign• Subset of scenarios necessary for full code coverage
Mission scenarios
case_1
case_2
case_n
• MVM• Trajectory
generation • Low-level control
Simulationenvironment
(vehicle, sensors…)
Test framework
reports
vehicle state
select new scenarios
PC / embedded PC / real-timePass/Fail criteria
FLIGHT SOFTWARE QUALIFICATION
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CONTINUOUS INTEGRATION
Report generation after every batch of tests
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CONCLUSION
SpaceX
Flight Testing on INCAS DTV, Q3 2019
ESSL
Design – Simulation – Validation
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www.embotech.com