Astrium ‘Robotics and Autonomy’ Test facilities - hardware and software verification - for 28 Feb 2012 Harwell meeting. Tony Jorden Elie Allouis.

Outline (1) Mars Yard  Current Mars Yard  Photos/ Layout /Slope Bins  Soil Simulants & Health & Safety  Localisation System  Future Mars Yard  Specification (2) Autonomy and software testing  Overview of testing- as applied to ExoMars rover (autonomous navigation vehicle)  Comparison of small-scale and large-scale testing

Current Astrium Mars Yard (2009) - as used for ExoMars rover vehicle testing

Layout : As Built Team Building !  Terrain Area = 11m by 11m  EGSE Area = 11m by ~5m

Photos

Slope Bins  Internal test area  Humidity control- for dry soil.  Allows controlled illumination  Aluminium slope bins used to create slopes up to 20 degrees  Two slope bins :  5m wide x 3m deep – used primarily for cross-slope trials  3m wide x 5m deep – used primarily for up/down-slope trials

Soil Simulants  Three soil types are used in the current Mars Yard  Slope bins: Sand representative of Engineering Soil 2 (ES2)  Flat area: Sand representative of Engineering Soil 3 (ES3)  Remaining area: Temporary material (red sand & rocks)  Health & Safety  Main risk is airborne sand  Minimal risk in current Mars Yard due to composition / particle size:  Silica-based sand is not flammable, therefore cannot cause a dust explosion  However, if sand becomes contaminated, risk of fire / explosion increases – in particular blasted sand should be avoided  Finest sand in the Mars Yard (Engineering Soil 2) has less than 0.2% of particles with grain sizes < 63 microns  Dusts with particle sizes below 63 microns may cause irritation to the nose and throat but dusts need to be 10 microns or less to be respirable and cause respiratory irritation

Localisation System  The Mars Yard Localisation System  54 markers (known as fiducials)  Installed in the ceiling  “i-Position” measurement system (Inition Ltd)  Pattern scanned using a theodolite and loaded into rover computers  Camera on the rover compares what it sees with this pattern  Outputs position and attitude data to a very high degree of accuracy  Used as a ‘ground truth’ for localisation sources on the rover

Extended Mars Yard

Specification  Key points from specification:  Mars Yard  Dimensions of 30m x 14m  No obstacles in terrain area (except Rocks)  Lighting: representative spectrum, minimum light intensity at ground level (lower than Mars) and uniform.  Dedicated loading area (with access ramps to terrain)  Ventilation system for terrain areas  Radiative heaters for terrain areas …soil must be dry- hence the need for an indoor test area  Extension of localisation system  Representative terrain – reference soils (& rocks /slopes) - commercial sand but similar colour & density… - emphasis is on integrated tests, including vision.  Separate area for perception tests  Control Room  “Office” environment  Rover control system (GNC, PSS, DHS etc)  Visibility across complete Terrain

Astrium Test facilities for software/autonomy testing - as used for ExoMars rover vehicle testing (eg navigation/GNC) and smaller-scale robotics instrumentation

Autonomous Systems – Key Elements  The end result is a system (eg. Rover) autonomously performing its function in the mission environment (eg. Martian surface)  A number of key elements (building blocks) are needed to develop and validate such a system Flight Software Numerical Models Hardware Breadboards Eg. Mars yard Flight Hardware Environment Mission Elements Development and Testing Elements Autonomy Algorithms

GNC Simulator Example of test case Rover start location Rover target Path planned by rover while traversing terrain 5m Areas classified as obstacles by rover White: Unsafe Dark grey: “Do not plan a path into” Areas classified as safe by rover Green: Low cost Red: High cost

ExoMars GNC development and validation Benches GNC software specification documents Development Sim GNC equipment & environment models FVB GNC flight software Prototype GNC algorithms Bread board rovers Prototype GNC algorithms GNC equipment & environment models NSVF Complete flight software All equipment & environment models ETB Complete flight software Env models Algorithm & model developmentFormal verification and validation Coding of GNC software V&V of models [Verification & Validation] EM/EQM H/W FVB= Functional Validation Bench NSVF= Numerical Software Validation Facility ETB=Electrical test Bench EM= Eng. Model EQM= Engineering Qualification Model e.g. Rover Dynamics Model Hardware model Used for operations also

Mars Yard test facility

Testing robotic equipment- small-scale Off-line development & test of control software and simulations Test bench- includes hardware in-the-loop Adaptable user-defined control and monitoring options LiRA Robotic arm – typical robotic payload

Large-scale and small-scale comparison  Overall process is the same  Numerical simulation facilities (for faster execution, repeatability…)  Test bench with hardware (may be multiple elements) in the loop  Hardware models must be designed to suit the scope of the testing.  Environment needs to be correct (e.g. terrain, lighting…)  For smaller scale systems some elements may be merged or omitted  E.g. rover simulation may include PANGU visual environment model, but not needed for robotic arm testing.  Still need to develop and test software independent of hardware initially (including simulations).  Still need to verify with appropriate hardware models and facilities

Summary of ExoMars facilities Astrium, under the ESA ExoMars project, has developed critical technologies using:  A Mars yard which allows for different soils and visual test conditions  Rover breadboards representative of the 2011 ExoMars flight design  Numerical simulators modelling the Martian environment, the Rover dynamics on the Martian surface, the sensors and actuators, etc.  The ExoMars GNC algorithms running on the Rover breadboards and on the numerical simulators  Several tools for the development and validation of the Rover autonomy  The integrated autonomy system has demonstrated its TRL 6  The next level (TRL 7) is the demonstration already on the Mars surface