Development Robotic Arm System Testbed for the Mars Sample Return Campaign

This paper presents the design, assembly, and commissioning of ‘Bradbury’, a robotic arm system testbed for the Sample Retrieval Lander mission’s Sample Transfer and Handling Subsystem. This work is part of the Mars Sample Return campaign, which aims to bring Martian samples to Earth for groundbreaking scientific analysis. A key part of this mission is the robotic transfer of sample tubes from the surface of Mars to the ascent vehicle, necessitating a sophisticated robotic arm and advanced control strategies. The control algorithms are being developed and tested at NASA’s Jet Propulsion Laboratory using R&D testbeds, while ESA develops the seven degree of freedom flight robotic arm hardware. The Bradbury testbed contains a development arm to be used for robotic algorithm and software development and testing, which was designed and built to closely resemble the kinematic configuration and mechanical performance of the flight arm. The Bradbury arm uses off-the-shelf drivetrain, sensors, and cable harness components, mirroring flight counterpart performance with reduced complexity and cost, and increased modularity. Arm actuators were tested individually for performance characterization and load capability qualification, while the integrated robotic arm was kinematically calibrated using vision-based metrology. Altogether, the Bradbury testbed provides an integrated robotic hardware and software venue to preform software development testing for sample transfer operations early in the project lifecycle.