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

Tony JordenElie 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

Slope Bin #1(5m x 3m)

Slope Bin #2(3m x 5m)

Flat area(6m x 3m)

DESKSDESKS RAMP

11m

11m

1m

1m

0.3m

~2.7m

Team Building !

Terrain Area = 11m by 11m

EGSE Area = 11m by ~5m

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 SoftwareNumerical

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 roverWhite: UnsafeDark grey: “Do not plan a path into”

Areas classified as safe by roverGreen: Low costRed: High cost

ExoMars GNC development and validation Benches

GNC software specificationdocuments

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 development Formal 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 BenchEM= Eng. ModelEQM= 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