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NASA LuSTR – GRASP Lab, University of Pennsylvania
NASA LuSTR – GRASP Lab, University of Pennsylvania
Advisor: Prof. Mark Yim | Collaborators: SungLab (UPenn), Kod*lab (UPenn), Penn Soft Earth Dynamics Lab (UPenn) LASSIE Lab (USC), NASA Ames.
Advisor: Prof. Mark Yim | Collaborators: SungLab (UPenn), Kod*lab (UPenn), Penn Soft Earth Dynamics Lab (UPenn) LASSIE Lab (USC), NASA Ames.
DSCN2494.MOVVideo: Successive multi-robot collaboration in White Sands NM (Aug 2025)
As part of the NASA-funded Lunar Surface Technology Research (LuSTR) program, our team is developing autonomous, cooperative robots that can assemble and deploy infrastructure on the lunar surface. The platform demonstrates the first heterogeneous multi-robot docking and cooperative-mobility behaviors tested in planetary-analog terrain
This project demonstrates a compliant, modular docking mechanism and rover platform enabling heterogeneous robot collaboration for planetary exploration. Iterative hardware design and field testing culminated in the successful White Sands trials and an upcoming NASA Ames demo.
The TRUSSES Rover (pHusky) is one of the core ground robots in this modular, multi-robot system. My work focuses on the design, mechanical integration, and field validation of this rover, emphasizing mobility, docking, and recovery operations on granular terrain.
My Role and Focus (Summary)
My Role and Focus (Summary)
I lead the mechanical and systems integration of Penn’s TRUSSES robots, covering hardware design, low-level control, and field validation. My work spans the docking system (V1–V4)—from an early 3-DOF turret and passive coupler to a fully compliant, field-ready mechanism—and the rover platform (V1–V4), redesigned for soft-terrain mobility through modular ride height, a custom chain-sprocket drivetrain, and improved thermal management. I developed and tested polyurethane paddle tires informed by terramechanics analysis and consultations with granular-media experts, enabling successful traversal at White Sands NM.
Beyond mechanical work, I integrate autonomous low-level control and ROS 2-based docking behaviors, linking hardware with high-level planners and perception modules. Current efforts focus on the V4 rover and docking hardware for the upcoming NASA Ames demonstration, emphasizing drivetrain reinforcement, sand-proofing, PCB electronics, and full autonomy integration.
My Role and Focus (In-Depth)
My Role and Focus (In-Depth)
I lead end-to-end systems integration across TRUSSES: mechanical design, low-level control, autonomy, and field validation.
Docking System (V1 --> V4): Co-led development with Raymond Yang, from a 3-DOF turret (probe) + 2-DOF passive drogue, inspired by probe-drouge design, from concept to a fully compliant, robust, autonomous, and modular mechanism that has been validated across sand courts, beaches, and White Sands, NM. I owned the mechanical and manufacturing iteration, push-lock latching behavior, and compliant spring/gear system.
Rover Architecture (V1-->V4): Drove the redesign from an proof-of-concept chassis to a field-ready platform by iterating over critical field-tests, such as body chassis, drivetrain, electronics, and thermal limits
Ride height: Proposed and implemented a modular ride-height system (≈2× clearance).
Powertrain: Replaced direct drive with a chain–sprocket drivetrain and a custom axle→hub assembly (lathe/mill, GRASP shop), designed for replication (4 active + 2 spares).
Thermals: Modeled motor P–T curves to set duty-cycle envelopes; added white cladding to mitigate solar loading for >100 °F operation.
Front geometry: Designed a domed front-end(inspired by X-RHex) to reduce plowing in sand.
Batteries/Electronics: Introduced modular, field-swappable packs; migrated from protoboards toward PCB layouts for reliability.
Sand mobility (paddle tires): Researched dune-buggy/terramechanics, consulted Prof. Douglas Jerolmack, and designed polyurethane paddle tires with modular dovetail inserts (tunable spacing/contour) to balance compaction and shear—critical to successful traversal at White Sands.
Autonomy and control: Built low-level actuation and ROS 2 integration for docking and mobility; led system integration with high-level planners and perception (vision/GPS/mocap hooks).
Field validation: Planned and executed multi-robot trials (pHusky rover + Spirit quadruped + turret/docking) on slopes and variable sand; demonstrated heterogeneous rescue (Spirit pushing/pulling pHusky) and a TRUSS link (Spirit→pHusky→Spirit); established reliable telemetry/logging workflows.
Current (V4 → NASA Ames): Hardening for demo with dual-bearing drivetrain supports, internalized drivetrain mounts, sand-seal strategy across seams, carry/lift handles, PCB power distribution, and integration of autonomous driving + turret control and a custom pushing gait for Spirit.
What Makes this Work Novel
What Makes this Work Novel
The platform demonstrates the first heterogeneous multi-robot docking and cooperative, risk-aware mobility behaviors validated in planetary-analog terrain. These capabilities are enabled by hardware that can autonomously dock, coordinate, and adapt its traversal strategy based on granular-terrain feedback. The system integrates a compliant docking mechanism, a Spiral-Zipper turret, an evolving rover architecture, and a 2×-scaled RHex platform, each optimized for robust performance in soft-sand and unstructured environments.
Achievements and Current Milestones
Achievements and Current Milestones
Three field-ready systems deployed: Rover (pHusky), Quadruped (Spirit), and Docking + Turret subsystems tested across sandy courtyards, coastal beaches, and White Sands, NM.
Four-iteration docking mechanism designed and validated through progressive field trials.
River re-design encompassing drivetrain, thermal management, electronics, and polyurethane paddle-tire systems—enabling successful multi-robot “rescue” demonstrations.
V4 rover currently in development for NASA Ames Research Center demonstration in Fall/Winter 2025.
pHusky V1 (proof-of-concept)
pHusky V2 (Sandy Beach)
pHusky V3 ( White Sands)
pHusky V4 (NASA Ames)
Left to Right: 2xRhex , First iterations of docking mechanism, PsuedoHUSKY ( Ground Rover)
PseudoHUSKY - Made with Clipchamp.mp4IMG_4106.MOVA full technical report detailing the rover's, docking mechanism, and 2X-RHex mechaincal evolution, design rationale, and field-test deployment data is available below.
Left to Right: V1 Rover (Proof of Concept), V2 (Beach), V3 (White Sands), V4 (AMES, coming soon!)
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