document title/ titre du document REGIONAL MARS ROVER FOR SCOUTING AND SAMPLE COLLECTION PART 1: MARS ROVER CHASSIS ANNEXE B 1: SYSTEM REQUIREMENTS DOCUMENT prepared by/pré paré par ESA reference/ré ference Aurora/LJ/KC/011.03 ANNEXE B issue/é dition 3 revision/ré vision 0 date of issue/date d é dition July 15th, 2003 status/é tat Document type/type de document System Requirements Document Distribution/distribution
APPROVAL Title titre issue 3 revision issue revision 0 author auteur date July 15th, 2003 date approved by approuvé by date date CHANGE LOG reason for change /raison du changement issue/issue revision/revision date/date CHANGE RECORD Issue: 3 Revision: 0 reason for change/raison du changement page(s)/page(s) paragraph(s)/paragraph(s)
T A B L E A B L E O F C O N T E N T S O N T E N T S 1 INTRODUCTION... 4 1.1 Scope of the Document...4 2 REQUIREMENTS... 4 2.1 Overall requirements...4 2.1.1 Other System Requirements 8 2.1.2 System Constraints 8 2.1.2.1 Environment Constraints 8 2.1.2.2 Interface Constraints 8 2.1.2.3 Implementation Constraints 8 2.2 Subsystem Requirements...9 2.2.1 Specific Requirements on parametric tool 9 2.2.2 Specific Requirements on 3D simulation tool 10 2.2.3 Specific Requirements on single wheel testbed 12 2.2.4 Specific Requirements on wheel AND FLEXIBle SUSPENSION Study 13 2.2.5 Specific Requirements on rover PROTOTYPE locomotion evaluation tools 14
1 INTRODUCTION 1.1 Scope of the Document This document describes the preliminary system requirements for the Regional Mars Rover for scouting and sample collection Part1: mars rover chassis contract. 2 REQUIREMENTS The requirements for RCET are given hereafter and shall be reviewed and completed by the Contractor to insure the completion of the goals defined in the chapter 1.3 of the Regional Mars Rover for scouting and sample collection Part1: mars rover chassis statement of work. These requirements are defined for planetary mini wheeled rovers in general. In some cases, it may happen that they are too general and restrictions may be needed. Then, the ExoMars mission [RD10] should be taken as a typical reference case. Requirements numbering: R: requirement M: Mandatory (use of shall ) G: Goal (use of should ) These requirement are important wishes which may be ignored if it is conflicting with mandatory requirements and would increase complexity, risk or cost to an extend which is considered unreasonable. 2.1 Overall requirements RM.1010 The RCET shall allow prediction of the locomotion performances of planetary wheeled mini-rovers. RM.1020 The RCET shall be a standalone system The tools shall be sufficient themselves to fully predict the performances of rover without external additional tools.
RM.1030 The RCET shall allow characterization of planetary rovers locomotion at different stage of the locomotion design phases. Preliminary conceptual phase Advanced design phase (availability of 3D CAD model) Wheel hardware prototype test phase Rover hardware prototype test phase RM.1040 The RCET shall allow irrefutable comparison of different rovers and locomotion concepts. The tools error shall be minimized and the tool shall be calibrated RM.1110 The RCET shall allow locomotion characterization over the following aspects: Trafficability Manoeuvrability Terrainability RM.1120 The RCET shall allow the characterisation of the wheel-soil interactions for any wheel of following dimensions: Max diameter 500mm. Max width 300mm RM.1130 Rover s maximum controlled linear velocity shall be 200m/h (TBC) RM.1210 The RCET shall make use of the most representative mars terrain characteristics available for both HW and SW The Contractor shall make use of the given reference documents about the terrain characteristics of Mars.
RM.1220 The terrain model shall take into account the following different aspects: Inclination (slopes) Homogeneous regolith Non homogeneous regolith Rocks distribution RM.1230 The RCET shall allow definition, tuning, storing and use of predefined terrains with displayed or measured characteristics. RM.1240 The RCET shall take into account the rover controller if necessary In case of internal degrees of freedom or active suspension, the control strategy shall be simulated. RM.1250 The RCET shall be kept independent of the navigation strategy and software The navigation strategy shall not influence the evaluation. In fact the locomotion performances results shall feed any kind of navigation controller. RM.1260 Several types of Soil-wheel interaction models shall be able to be computed. Bekkers equations about soil-wheel interaction shall be the default. RM.1270 Choice for other types of computation than Bekker s equations (refined models, user models ) shall be available RM.1280 Soil-wheel interaction models shall be available in a C-library with User- Manual
RM.1290 The RCET shall take into account the planet gravity. RM.1300 The RCET shall allow comparison with rover chassis characterisation on Earth. This shall help the tool assessment on Earth RM.1310 The characteristics of the terrain shall be measured and measurement should be available This is essential to assess the prediction tools RG.1320 The hygrometry and temperature of soil should be taken into account. RG.1330 The RCET design, implementation and operations should insure that the hardware tests are consistent and reproducible. Otherwise, the tools results and chassis comparison are doubtful. RM.1340 The RCET shall provide a reference run (benchmark). This shall verify the integrity of the following tests. RM.1350 The wheel sinkage into the soil shall be taken into account RG.1360 The RCET shall have user-friendly MMI RM.1370 The RCET shall provide the visualisation of the data and measurements. RM.1380 The RCET shall provide reporting functionalities This shall allow having standard output of the use of the RCET
2.1.1 OTHER SYSTEM REQUIREMENTS RM.2010 The system shall comply with norm for machinery 89/392/CEE and following amendments RG.2020 The system should be designed to unable the spread of martian-like dust/sand over the place (for HW testbeds). 2.1.2 SYSTEM CONSTRAINTS 2.1.2.1 Environment Constraints RM.3010 The system shall be designed to run at ESTEC RG.3020 Simulation/computation tools should make use of commercial standards with 10 years durability. 2.1.2.2 Interface Constraints RG.4010 The system should be designed to be relocated in a laboratory environment RG.4020 The system should be operated by one person. RM.4030 The system shall make use of normal 230VAC power. 2.1.2.3 Implementation Constraints RM.5010 The system shall be designed to be transported in Europe with a truck.
RM.5020 Computations shall make use of PCs with Linux operating system (SuSE v 7.0 or better) RG.5030 Java programming language should be used when possible 2.2 Subsystem Requirements 2.2.1 SPECIFIC REQUIREMENTS ON PARAMETRIC TOOL RM.6010 The parametric tool shall allow predicting locomotion performances for a specified terrain with different types of rover parameters. The predictions will be refined with the number of rover s parameters available RM.6020 The parametric tool shall allow visualizing the influence of the design parameters. Variation of parameters in parametric equations shall be available. RM.6030 Performances predictions shall be computed from design parameters (forward computation for evaluation) as well as design parameters shall be computed from goal performances (inverse computation for design and optimisation) The values of some parameters shall be able to be fixed and the parametric equations to be reversed. RG.6040 The parametric tool should provide a user-friendly man-machine-interface. RG.6050 The parametric tool should provide a coherent methodology for the design
RM.6060 The parametric tool shall allow the user to understand and visualize what is computed. Typically, the user shall be able to visualize the equations RM.6070 The parametric tool shall allow graphical display of the results of parametric computation RM.6080 The parametric tool shall allow comparison of different design RM.6090 The parametric tool shall allow a reporting of the evaluation, design or comparison process RM.6100 The parametric tool shall allow definition, storing and reuse of robot designs Typically, a rover design database shall be available with all management functionalities 2.2.2 SPECIFIC REQUIREMENTS ON 3D SIMULATION TOOL It is not envisaged to build a simulator from scratch in the frame of this activity since many 3D simulators are available on the market. The Contractor is then strongly advised to use an existing simulator fitting the requirements of this activity. The following requirements are complementary to the overall requirements. RM.7010 The 3D tool shall allow the simulation of a planetary rover on a representative 3D environment to complement the parametric tool. RM.7020 The 3D tool shall predict the locomotion performances of a complete rover design. It shall especially handle the obstacle crossing abilities, steering abilities and wheels interactions.
RM.7030 The models shall be able to be imported directly from the most used commercial CAD tools like CATIA, SOLIDEDGE The Contractor shall demonstrate an easy way of using the RCET in the Industry, if this requirement is not fully met. RG.7040 The models and especially the terrain should be able to be exported directly to the most used commercial 3D visualisation softwares. RM.7050 The soil-wheel interactions models shall be implemented and if several models are available, the user shall be able to choose among them. RG.7060 A terrain generation function should be available with typical management functionalities (TBD) The usual terrain model is Digital Elevation Map but other formats exist. RG.7070 Several predefined typical terrain models shall be available. RM.7080 The rover locomotion capabilities shall be simulated All steering and internal degrees of freedom shall be controllable RM.7090 The 3D tool shall integrate all the models refinements created in the frame of this activity. Especially, the wheel and flexible suspension study results shall be taken into account RM.7100 Reporting shall be available.
2.2.3 SPECIFIC REQUIREMENTS ON SINGLE WHEEL TESTBED If such testbed exists already in Europe, it is not intended to create a concurrent one. The Contractor shall then propose upgrades if necessary and make use of such facilities. RM.8010 Adaptation of wheels shall be easy and cheap. Fixation shall be good enough to avoid any measurement error or noise. RM.8020 Wheel-soil slippage shall be controlled from 0% to 100%. It includes all the necessary odometry acquisition on the wheel RM.8030 Front and rear locomotion testing shall be available. RG.8040 Effects of an obstacle hit should be measurable. RG.8050 Soil compaction should be controlled. RM.8060 Wheel sinkage shall be measured (TBC) RM.8070 Gravity shall be controlled. (TBC) RM.8080 The following values shall be at least measured (TBC): Power consumption of wheel Normal reaction. Tangential reaction Transversal reaction Wheel s Slippage Wheel s rotation
RM.8090 Orientation of the wheel shall be possible. (TBC) This functionality should allow more configuration testing RG.8100 Several types of terrain shall be testable easily. RM.8110 Main switch and emergency stop button shall be available. RM.8120 Safety and integrity of the operator shall be taken into account in the design. 2.2.4 SPECIFIC REQUIREMENTS ON WHEEL AND FLEXIBLE SUSPENSION STUDY RM.9010 The front and rear motion shall be studied. RG.9020 The effect of hitting a rock should be studied RG.9030 The following wheel s shapes shall be studied as a minimum: Cylinder Sphere Tore RG.9040 Variations in the dimensions shall be taken into account For cylinders, the width versus diameter ratio shall be taken into account.
2.2.5 SPECIFIC REQUIREMENTS ON ROVER PROTOTYPE LOCOMOTION EVALUATION TOOLS If such testbed exists already in Europe, it is not intended to create a concurrent one. The Contractor shall then propose upgrades if necessary and make use of such facilities. RM.10010 The HW tool shall allow full verification of the performances predictions RM.10020 The tools and methods shall be applicable for mini rovers: Minimum size fully deployed of 200mm length and 200mm width Maximum size fully deployed of 2000 mm length and 1500mm width Maximum weight of 200kg RG.10030 The size of the tools should be kept minimum. It is not intended to build a martian-like testbed like in the ESTEC robotic laboratory. For example, an inclinable plan should fit some needs of testing the full prototype rover, since locomotion performances are not linked to long duration locomotion. If a large martian testbed is compulsory, the Contractor shall propose the use of existing European facilities. Outdoor testing is also a possibility to be taken into account. RM.10040 The tools shall be designed to be used outside with good weather conditions. RM.10050 The study shall provide a list of necessary rover telemetry, which should be available during field-testing to compute the rover locomotion performances (power consumption, odometry ). The LRM shall be tested as it is.