2.2.1 Planetary Rovers

This segment of the program supports the development of robotics to satisfy the planned requirements for exploration of planetary surfaces. These plans call for robotic reconnaissance and exploration systems traversing the Mars terrain. During such missions robots will explore potential landing sites and areas of scientific interest, place science instruments, and gather samples for analysis and possible return to Earth. The robotic systems required for these operations will require high levels of local autonomy, including the ability to perform local navigation, identify areas of potential scientific interest, regulate on-board resources, and schedule activities, all with limited ground command intervention. The objectives of the tasks within this segment of the program are to develop these abilities, as well as conduct research into mobility systems, miniature mechanisms, planning, and on-board navigation. Specific applications are to the Mars Pathfinder, Mars Surveyor Network project and other programs planned by the Space Science user community.

Long-Duration Microrover Survivability and Mobility

Behaviour Control of Multiple Robots

Micro-Lander Dexterous Manipulators

Science Rovers / Remote Geologist

Touch Guided Grasping

Planetary Aerobot Technology

Pathfinder Planetary Rover

Technology Transfer Roadmap Details

Long-Duration Microrover Survivability and Mobility

In the context of the present Mars Surveyor Program (MSP) lander architecture, science return available from mobile robotics appears limited. The Mars 1998/2001 lander integrated science deck payload -- per a recent Mars '98 Science AO release -- is capped at 20 kilograms, 70 liters, 25 watts and $20M. Resulting Mars '98 proposal concepts have favored a primary allocation of resources (60-80%) to lander science instrumentation, and relegated rovers of the 4-6 kg class to simple sample collection or instrument deployment in the near field a few meters distant. This rover resource budgeting has been motivated by perceptions of operational risk, science return as function of rover mass, and that a majority rover mass budget (15-20 kg) will require a fundamentally new lander concept. Specific to microrover designs in the 4-6 kg ranges, science community concerns for MSP mission design and rover utilization beyond '98 include:

limited diversity of sample acquisition and manipulation (sample exposure, soil and fresh rock collection, subsurface access & striated extraction, burial/emplacement of instruments)

minimal on-board science instrumentation and lack of opportunity for in situ analysis, also confinement to a limited area (10's of meters)

given a capable on-board rover instrument, time-bandwidth data constraints on mission efficiency relative to line-of-sight lander-rover communications (versus a direct high data rate orbiter uplink from a larger rover)

limited mission duration (10 days) and reduced science efficiency due to high levels of ground intervention (little on-board sensor-based autonomy)

cost, particularly flight-specific electronic design & qualification

In essence, flight relevance of 5 kg class rover operations is severely curtailed by lack of science payload and survivability, given the primary resources go to rover system infrastructure -- to chassis, actuation, power and thermal management. The purpose of this task is to attack some of the above assumptions limiting microrover design head on. These are technology challenges -- can they be answered? -- how can they be answered and benchmarked?

Focus and Directions

The basic goal of this work is thus to shift the 5 kg microrover paradigm to one of higher-yield, longer duration science -- for both equatorial and polar Martian extremes. Fundamental issues include reducing mass and volume of rover structural and actuator design, achieving high density power delivery over wide thermal ranges, maintaining a stable thermal environment with a minimal WEB mass-volume product (facilitating use of more conventional, mass-and-volume efficient commercial electronics), creating new classes of ultra-light, environmentally resistant miniaturized robotic sampling devices (including active tooling), controlling force contact tasks of an ultra-light rover-manipulator platform on uneven terrain, and integrating broad-capability science instruments into these rover architectural innovations. The resulting technology products will be valuable both to breakthrough microrover design for local operations, and the above-noted larger scale science rovers dedicated to long distance traverse and orbiter-based communications. If most of these objectives can be addressed, a 5 kg rover would become a viable vehicle for extended duration MSP science under line of sight (10-100 m), and could also provide a major technology option for the MSP Mars Sample Return circa 2005, particularly in context of a likely precision landing capability by that date. A small, low cost, survivable rover carrying significant instrumentation would also significantly broaden terrestrial interests in NASA robotics work, e.g. for military field operations, hazard detection, nuclear site inspection, etc.).

The primary technology thrusts of this task are mechanical and structural: R&D areas include vehicle mobility innovation, ultra-light/high-strength chassis materials and structural forming, integrated thermal enclosures from new materials (e.g., phase-change media), stable control of high-torque density micro-actuators using minimum complexity drive trains, integration of same with novel composite material manipulator and mobility architectures (including actively tooled effectors), quasistatic and dynamical modeling of resulting designs (under what conditions are they robust in realistic terrain and operational environments, e.g., VL1/VL2 traverses, and what kind of contact sampling & manipulation tasks can realistically be performed in same?). This task will develop and quantify these approaches/devices, and leverage resources of other ongoing Code X tasks to integrate & test working microrover systems. Leverage includes cooperative development with the Science Rover effort of a modularizable vehicle control, perception, & computing architecture -- from which this task uses a subset of capabilities (e.g., local hazard detection, lander heading determination, and sample localization/ discrimination). Working with ongoing Mars Exploration Technology tasks, we will innovate a class of miniature microrover-targeted sample acquisition devices (actively tooled micro-arm), develop related in situ robotically integrated instrumentation & analysis techniques (incl. new rover-borne NMR spectroscopic and multi-spectral imaging devices), create rover-relevant PCM thermal isolation/exchange structures and chassis integration techniques, and perform the first robotic design for rechargeable Li-system power supplies capable of low temperature cycling. We will demonstrate and characterize the system level capability of these advances in realistic terrestrial environments (simulated VL1/VL2 terrain), including extended duration rover tasks that give insight to achievable lander-rover interactions (sample retrieval and transfers, command frequency and control interventions, lander imaging requirements, etc.). Further, we will progressively verify that key technology design elements of the system can be environmentally qualified for Mars equatorial (-50 C) and polar (-100C) diurnal/seasonal extremes.

FY96 Develop a composite body rover and mobility system enabling a minimum onboard science mass and volume of .5 kg and .5 liter (including support electronics/interfaces) and demonstrate the system at 5 kg maximum weight for in situ science data collection in simulated Mars VL1/VL2 terrain. Implement with a nominal 10MB memory/10MOP computing capability (commercial architecture) for untethered operations in a single science sortie of 10m or more. Develop applicable servo control and evaluate use of a high-torque density, lightweight solid state motor for mobility actuation.

FY97 Develop a composite body rover and mobility system enabling a minimum onboard science mass and volume of 1.0 kg and .5 liter (including support electronics/interfaces) and demonstrate system at 5 kg maximum weight for in situ science sample data collection and onboard analysis (simple feature extraction, viz. NMR spectral analysis/peak detection in simulated Mars VL1/VL2 terrain). Perform a continuous transect up to 100m. Incorporate a WEB structure relevant to Mars 2001-2005 missions (e.g., non-RHU based aerogel/composite insulation, PCM energy storage capability at ~ 270 K), characterizing rover system mass impact, diurnal temperature excursions, and any performance degradation with time. Develop and demonstrate a solid state motor rover drive train, characterizing control performance and mass/volume/power trades relative to conventional electromagnetic solutions. Develop and demonstrate a microminiature composite sampling arm.

FY98 Within the design framework above, develop and integrate for rover operation a microminiature composite sampling arm with active end tooling, capable of exposing a fresh rock surface. Demonstrate this device in coordinated use with in situ sampling and analysis -- e.g.,designate a feature of science interest, traverse the near field to this object (rock, outcropping), expose the medium, sample/image, and perform an automated analysis of the data (of interest - yes/no). Determine by environmental testing if the prevailing WEB mechanical/thermal approach maturity is sufficient to a Class D flight design utilizing commercial electronics and computing.

FY99 Again, within the above design framework, develop a rechargeable Li-system low temperature power source commensurate with extended duration rover sorties. Evolve the sampling device for micro-coring. Demonstrate capability to make multiple sorties about the lander near field (nominal 10-30m radius). The rover will utilize an on-board instrument and analysis to discriminate a sample of interest, and actively extract a core sample. The rover will then return to the lander, replenish its power as needed, and deposit the sample at the lander for detailed assay. Alternatively, as modeled for a MSR (2005) operation, the rover will rendezvous with a sample containment facility. (A significant challenge within this demonstration will be memory management, as pertains to progressive traverses, terrain map history, sample area statistics, etc.).

Points of Contact:
Paul Schenker
(818)354-2681
paul.s.schenker@jpl.nasa.gov

Brian Wilcox
(818) 354-4625
brian.wilcox@jpl.nasa.gov

Behaviour Control of Multiple Robots

Objectives

To develop autonomous capabilities using behavior-control methods to enable new classes of planetary exploration missions. In these missions very low mass systems should be able to operate completely autonomously and yet be able to produce good science results.

Approach

The approach is to couple the physics of a robot and its interaction with the environment with relatively simple computational schemes that modulate these dynamics. This leads to very robust systems that can operate over a wide variety of conditions as they vary from the baseline.

There are two thrusts to this work. One is to develop the capabilities of rovers in the 5 to 10 Kgm range, and the other is to develop new rovers inthe 10 gm range.

The 5 to 10 Kgm rovers navigate autonomously using vision. Rather than use structured light this task concentrates on purely passive lower energy approaches---lower energy in that no lasers are needed, and lower energy in that very little computation is needed. Many individual vision agents will compute desired actions from simple properties of the image. The actions will be combined to produce local navigation strategies. Additionally a manipulator with series elastic springs in the actuators will be used with these rovers. It couples the physics of a real spring with the behavior of a virtual spring to allow for advanced compliant tasks with the arm, such as hammering, splitting, and coring. We will work towards coupling the vision system and the arm, for vision guided manipulation of samples.

The second class of rovers are very lightweight--on the order of 10gms. In this task we will work closely with JPL to develop a generic platform which can accomodate a variety of JPL produced micro instruments. We will use ideas developed earlier in the program to have many of these very small rovers cooperate, without any global control system. Rather, local communication and signalling will be used to have a provably correct set of global behaviors emerge.

Focus and Directions

Jun 96 Complete outdoor navigation experiments with the Pebbles robot.

Jun 96 Demonstrate hand eye coordination in sample acquisition.

Dec 96 Demonstrate coordinated outdoor navigation and sample acquisition with an onboard manipulator.

Dec 96 Demonstrate a 10gm rover navigating in sandy and rocky terrains.

FY 97 Demonstrate a totally autonomous traverse outdoors of a rover with manipulator collecting geologically interesting samples.

FY 97 Demonstrate a 10gm rover collecting science data with a single micro instrument.

FY 98 Demonstrate a totally autonomous traverse with autonomously selected geological sites for coring and compliant sampling.

FY 99 Demonstrate a swarm of micro rovers carrying out coordinated and useful science experiments in an outdoor environment.

In FY 1995, this task was incorporated into the Rover Technology task, while work on the Boadicea research vehicle continues.

Point of Contact:
Rod Brooks
(617) 253-5223
brooks@ai.mit.edu

Micro-Lander Dexterous Manipulators

This task develops robotic technologies for planetary surface science, specifically, in situ science operations on, or from small-and-micro-lander spacecraft. The task emphasis is manipulation devices, advanced actuators, and their controls. The operational goal is increased science capability and productivity, both as a result of robotic enhancements to mission set design, and, improved science payload budget due to reduced robotic mass, volume, power, and cost. The NASA Mars Surveyor Program missions of 1998, 2001, 2003, and 2005 (a possible sample return) are potential technology applications, wherein lander-based-or-deployed robotic devices will acquire soil and rock specimens, emplace & retrieve surface instrumentation, and microscopically view & spectroscopically scan surface features of interest. Flight payload resources are limited in these MSP missions: for example, the Mars '98 science package is a 20 kilogram, 70 cubic liter, 25 watt (daytime average) design capped at $20M, of which 30% might be available to a robotic system giving good near-field coverage (manipulator) or beyond (rover, etc.). Our initial task efforts focus on conception and ground lab demonstrations of new structural, electro-mechanical, material components enabling an affordable, lander-based robot arm of two meter or greater reach into the lander science near field. One major task technology thrust develops a new miniature, lightweight, high torque-density solid state motor (SSM) for harsh operational environments (e.g., Mars polar climates). Another complementary technology thrust develops new robot manipulator and science effector architectures based in high-strength, lightweight composites, integrating the SSM actuation (requiring fundamental advances in both servo and task controls of this new motor class). In 1995, we developed a first prototype 3-d.o.f. serial lander manipulator using conventional commercial DC motors, and performed realistic ground laboratory simulation of Mars lander-based sample acquisition via an instrumented end-effector -- as shown in the accompanying photograph. This novel telescopically deployed arm design, compared to similarly scaled Viking lander technology, is the basis for future five-fold reduction in lander arm mass and stowage volume, while achieving greater dexterity. Drawing on this initial Code X developed technology concept, JPL supported an externally-led proposal for a robotic science payload on the Mars'98 mission. Our work in FY96 and beyond pursues these major objectives: basic advances in SSM design, fabrication, and flight environmental operability; innovation of small, scalable composite manipulators consistent with Mars'01/'03 flight constraints (including options for longer-range rover platform utilization); development of ultra-light effectors and active science tooling consistent with mission MSP functions guidelined by Mars science advisories (MarsSWG); and, ground lab evaluation of these advances in realistic scenarios mirroring experimental interests and themes of participating science users.

FY95 Develop a three degrees of freedom arm capable of two meter full extent reach and stowage volume reduction into a nominal 10 liter space (via gas deployable segmented links) -- demonstrate the arm in simulated Mars lander operations such as sample acquisition [Level 1]. Initiate a JPL/MIT program in development of low mass-and-power, high torque solid state actuators.

FY96 Develop, demonstrate, and evaluate under task space control an evolved full composite body arm/effector structure, with the goal of 20-30% cumulative weight reduction [Level 1]. Develop and characterize a solid state motor (SSM) joint servo control, demonstrating same for application of the JPL/MIT motor designs to a lightweight sampling end effector. Validate SSM analytic design model on first prototype JPL/MIT motors. Initiate low temperature (-100 C) motor design.

FY97 Develop and demonstrate an integrated composite/SSM joint- actuated arm, with the goal of 30-40% cumulative weight reduction; develop and instrument this arm with an active science sampling device (e.g., core- drill/chipper/scraper) reflecting Mars science advisory priorities [Level 1]. Develop and demonstrate in relevant environment (temperature/pressure/ ambient/etc.) a flight-targeted SSM.

FY98 Show capability to scale the composite arm/SSM design concept as would enable use in multiple platform settings -- for example a design consistent with micro-lander (~4-8 kg total) science payload or mini-rover (12-15 kg class) architectures -- derived requirements to be defined in cooperation with MSP '01 interests and science advisories [Level 1]. Develop and characterize a stable and reliable approach to this arm's task space SSM control. Quantitatively characterize and validate analytic modeling techniques for the flight-targeted SSM design. Pursuant to JPL science interest, develop an effector/end-tooling concept demonstrating integral micro-science instrumentation.

Point of Contact:
Paul Schenker
(818)354-2681
paul.s.schenker@jpl.nasa.gov

Science Rovers / Remote Geologist

The science rover task develops technologies that enable 20 Kg class microrovers to autonomously traverse many kilometers on the surface of Mars and perform scientist directed experiments and return relevant data back to Earth. Present microrover technology has several limitations that preclude more ambitious science rich missions. Current microrovers have very limited traverse (10s of meters), are not capable of sample acquisition and manipulation (i.e., soil and rock acquisition, subsurface access, burial of instruments), have limited science packages onboard, are designed for short term missions (10 days), and require careful and repetitive ground monitoring and control (limited autonomy) There is great interest in the science community to explore Mars by landing near interesting geographic areas and moving to pre-selected targets to offset landing errors. It is desirable to place instruments against outcrops or loose rocks, possibly collect rocks for return to Earth, and search an area for sample of interest. Also, long traverse will provide an opportunity to make observations and measurements along traverses and to access a wide variety of rocks from different regions of Mars.

This task will develop a small prototype rover that will carry several science instruments. It is envisioned that the mass of the rover will be 12-14 Kg and that of the science payload 5-6 Kg. This rover will have the capability to perform macro and micro imaging, visual and near-infrared spectroscopy, sample acquisition and manipulation. The rover will carry several yet to be defined science instruments. This task will emphasize scientist involved field testing and long traverses so that relevant onboard and ground based automation tools for realistic surface exploration of Mars are developed. Ames Resaerch Center is collaborating in this task by providing virtual reality displays and ground- based science data analysis and visualization.

Focus and Direction:

This technology development program combines both research and actual system demonstrations as a means of pushing the state of existing autonomous vehicle technologies for long range traverses for scientific exploration of the surface of Mars while maintaining flight program relevance. While the primary focus is research, the planned system demonstrations and scientist directed field tests provide a means of testing the robustness of the technology components within a viable mission scenario/environment. The task will have three distinct components: Rover System; Science System; and Ground System. In addition to the integrated level-I milestones described in the following each subsystem will have its separate level 2 milestones. Level-II milestones are planned to occur about six months prior to the integrated level-I milestones to show the readiness of new technologies in each subsystem.

The following major milestones are planned:

FY 96: Demonstrate Rocky VII functionality in lander local (20m radius) scenario with planetary scientists controlling rover in a site outside of JPL (i.e., Mojave desert). The demonstration will include the following elements:

Lander based multi-spectral imaging with autonomous analysis of spectral data

Multiple science task execution including sampling, imaging of rocks, and point spectrometer pointing/calibration directed by scientist in lander panoramic imagery

Autonomous navigation with faster onboard stereo vision based collision avoidance and goal confirmation based on rock constellation.

Science target selection by scientists in imagery data (ARC)

Analysis and visualization of spectrometer data

Remote operation from JPL

FY 97: Demonstrate long range rover prototype (Rocky VIII) in a 500 meter mission in a TBD site with scientist controlling the rover remotely from JPL.

Non-line of sight navigation

Integration of imaging spectrometer on rover with actuated mast system enabling rover panoramic imaging

Integration of sample surface preparation mechanism on rover

Autonomous execution of multiple science tasks (navigate to science target, prepare sample, use multiple instruments) up-linked in single command with failure recovery (science task re-sequencing)

FY 98: Demonstrate autonomous long range rover prototype (Rocky VIII) in week long 3+ km mission in TBD (i.e., Kilauea) with scientist control from JPL.

Telescience command of rover in terms of science goals/ procedures

Automatic on-board generation of science tasks/plans based on commanded science goals/procedures (select target as well as select and use instruments)

1 Km autonomous navigation for specified heading with on-board position estimation

Autonomous local navigation of local site to science targets of interest

FY 99: Demonstration of a 20 Kg rover (rover plus science payload) traversing at least 5 Km with several science instruments and sample acquisition/preparation directed by multiple scientist from around the world. Rover status and data will be available to the scientists involved as well as to anyone on the net.

Points of Contact:
Samad Hayati
(818)354-8273
Samad.A.Hayati@jpl.nasa.gov

Touch Guided Grasping

Objectives

This task addresses the development of technologies required for using robots to perceive, grasp and manipulate objects in remotely located environments. It incorporates development of real-time vision, touch sensing, end-effector mechanisms, haptic virtual environment (VE) technology and overall command and control strategies. The major goal is to enable human mediated performance of situational assessment, scientific experiments and maintenance tasks. In particular we seek to enable selection and reliable handling of materials for scientific study.

Approach

Develop methods for visual and touch information gathering.

Develop local autonomies for stable and reliable grasping

Develop adaptation techniques to ensure stable manipulator operation in unknown environments

Develop VE methods for providing human operators with visual and touch information about remote tasks and to enable them to remotely assess and guide task performance

Results should provide increase in success rate for acquiring desired materials and range of objects which can be grasped and manipulated.

Focus and Directions

FY96 Demonstrate visual/touch perception, selection and autonomous grasping of multiple rock samples. Fabricate Rocky7 manipulation system prototype and demonstrate sample acquisition in simulated planetary scenario. Demonstrate haptic interaction with remotely gathered material property information.

FY97 Incorporate material property sensor into end effector, collect and display to user via haptic interface. Online assessment of grasp feasibility using visual and touch information. Transfer of preliminary Rocky7 grasping algorithms to JPL. Begin real-time natural image segmentation to identify fixed and moving objects. Enable object grasping and sorting in laboratory scenarios.

FY98 Demonstrate human directed robotic object acquisition via interaction with 2D display and utilization of remote autonomies in simulated task environments. Transfer preliminary ultrasonic material property sensor to JPL. Demonstrate real-time natural image segmentation in planetary and on orbit-task scenarios. Enable object grasping and sorting in realistic task scenarios.

FY99 Demonstrate human directed robotic object acquisition (in simulated task environments) via high-level commanding in 3D virtual environment (VE) and utilization of robot grasping autonomies. Structure remote adaptation and autonomies to enable consistent remote operation from VE commands.

FY00 Demonstrate human mediated directing of remote tasks including survey, acquisition of samples and moving objects in simulated science experiments. Enable merging of human judgment and robot adaptive control to permit performing complex remote tasks reliably

Point of Contact:
Ken Salisbury
617-253-5834
jks@ai.mit.edu

Planetary Aerobot Technology

The purpose of the overall task is to develop the telerobotic technologies necessary to fly autonomous, robotic aerovehicles in the atmospheres of Venus, Mars, Titan and the Outer Planets. This activity focuses on the development of robotic technologies associated with free-flying, Venus and Mars, robotic aerovehicles or "aerobots". An aerobot is capable of one or more of the following activities: 1) Autonomous state determination; 2) Periodic altitude variations where altitude, amplitude and period are design variables; 3) Control of altitude and following a designated flight path within a planetary atmosphere using prevailing planetary winds; and 4) Landing at a designated surface location.

JPL has demonstrated a balloon buoyancy control concept which is applicable to Venus and Titan. This altitude control concept employs phase change fluids such that a planet's atmosphere is used as a giant heat engine to provide the mobility energy to ascend and descend at will. In addition, JPL is developing concepts for buoyancy and its control using infrared radiation up welling from the deep interior of these outer planet atmospheres to heat hot air balloons. There are potential flight experiment opportunities as early as 1999 for Venus, 2001 for Mars and 2000-04 for Titan.

Technical Objectives

1. Develop telerobotic control of free-flying balloon aerovehicles or "aerobots" in planetary atmospheres, capable of: 1) autonomous position, altitude, and velocity determination without intervention from the ground or by a support spacecraft; 2) executing periodic altitude variations where altitude, amplitude and period are design variables; 3) controlling altitude and executing a designated flight path within an atmosphere using prevailing wind patterns; and 4) landing at a designated surface location.

2. Construct a planetary aerobot testbed vehicle and conduct a series of terrestrial technology demonstrations which: 1) move gradually from manual altitude control of the robotic vehicle to fully autonomous altitude change and eventually landings; 2) achieve increasingly long-range mobility from widely separated launch and landing sites (first predicted sites followed by designated sites).

3. Transfer telerobotics technology to emerging planetary aerobot flight mission and technology demonstration opportunities (e.g., Venus '99 or '01, Mars '01, Titan '00-'04).

Approach

Planetary Atmosphere Autonomous Navigation: Basic research in 3-D navigation and maneuvers will be carried out in order to achieve long autonomous flights, including periods when the aerobot is not in communications. Research will address global navigability at planetary scales to various target site regions, as well as local navigability to terminally guide the aerobot to a specific target of opportunity within the a region. Engineering models of the planetary atmosphere weather patterns will be developed, focusing on relatively simple computer models for on-board autonomous navigation combined with periodic Earth or orbiter spacecraft updates.

On-Board Navigation Sensors and Perception: The navigation approaches to operation on Venus and Mars will be explored, sensor concepts developed and prototypes tested. Sensor options for vehicle navigation over surfaces may include a terrain profile sensors that match terrain profiles against previous mission topographic data; sun or star sensors for latitude determination; inertial systems for dead-reckoning navigation and gondola orientation; and terminal sensing using vision-based correlation methods.

Vertical Vehicle Mobility Mechanisms: Vertical vehicle mobility concepts for reversible fluid balloons include activation fluid reservoirs, heat exchangers valves that control the rate of fluid boil-off and condensation.

Planetary Aerobot Testbed (PAT) Vehicle: A terrestrial flight testbed vehicle, consisting of a reversible fluid altitude control balloon system, will be designed, fabricated and flown in Earth flights to test and demonstrate telerobotic technologies.

Focus and Direction

FY96 First reversible fluid balloon altitude control manual operation demo; First Venus autonomous balloon navigation sensors prototype flight demos.

FY97 First reversible fluid balloon autonomous flight demo; First Mars autonomous balloon navigation sensor prototype flight demos.

FY98 First reversible fluid balloon autonomous landing demos.

Point of Contact:
Kerry Nock
818-354-2153
kerry.t.nock@jpl.nasa.gov

Mars Pathfinder

Point of Contact:
Jake Matijevic
818-393-7804
jake.matijevic@jpl.nasa.gov