Worker Units
Each Worker combines a free-flying base, six-degree-of-freedom arm, gripper, docking interface, sensing, and local control.
STELLIFEX
Cooperative orbital robotics, organized around the object.
STELLIFEX is a platform of mobile robotic Worker Units that free-fly to a prepared worksite, dock and anchor, acquire shared objects, and coordinate manipulation for assembly, installation, and maintenance tasks.
Reference System
Mobile Robot
Worker A
Free base / Arm / Gripper
Central Coordination
Virtual Manipulator
Object pose to both tool poses
Mobile Robot
Worker B
Free base / Arm / Gripper
Controlled State
Shared Object
One coordinated path
Load Path
Prepared Worksite
Fixtures / Supports / Target
System Architecture
Independent Workers. Shared task state.
The reference architecture uses two Workers in one live multibody system. The wider platform is built around multiple independent units that share work through common object and worksite interfaces.
Prepared Worksite
Surveyed fixtures provide docking, positive latching, object support, prepared handles, and a target installation frame.
Coordination Engine
The shared layer selects the team, plans object motion, synchronizes tool commands, checks gates, and records the mission outcome.
Reference Mission
A complete local sequence in six controlled phases.
Assign
Select compatible Workers and assign distinct handles, docking fixtures, and approach corridors.
Free-Fly
Navigate independently through bounded corridors and perform terminal approach to the prepared worksite.
Dock
Seat and latch both Workers, settle motion and loads, and verify readiness before arm deployment.
Acquire
Retarget pregrasp from estimated handle poses and verify stable bilateral contact at both handles.
Manipulate
Move the object along one planned trajectory while monitoring contact, loads, limits, and placement.
Release
Release the object, retract both arms, unlatch, retreat through clear paths, and enter loiter.
Coordination Engine
The object trajectory is the common command source.
The Virtual Manipulator maps a desired object pose to both tool poses using the acquired object-to-tool transforms. Inverse kinematics then produces synchronized arm commands for each Worker.
Common object motion
Both arms derive their targets from the same time-indexed object trajectory.
Fixed grasp relationships
Acquired object-to-tool transforms preserve the intended shared geometry during manipulation.
Screened execution
Joint range, torque, collision, contact, latch, estimator, and phase conditions are checked before and during motion.
Virtual Manipulator
Input
Desired object pose
+
Geometry
Grasp transforms
=
Output
Two synchronized tool targets
Current Evidence
A simulation-validated architecture with retained failures.
The frozen engineering baseline covers the full reference mission in one MuJoCo multibody model. The limited development set varied Worker mass, asymmetric pairs, inertia, center-of-mass offset, and anchor compliance.
Physical Demonstration Path
Advance from characterized components to a complete two-Worker sequence.
Characterize
Measure gripper contact, wrist sensing, latch behavior, actuator authority, and test-rig disturbances.
Dock
Exercise free-base motion, capture loads, dual docking, positive latching, and condition-gated handoff.
Acquire
Verify bilateral contact and safe rejection across controlled pose, sensing, and calibration variation.
Integrate
Move, place, and release the object in complete nominal and off-nominal missions with independent measurement.
Program Discussion