Project 4

This project will investigate the design and evaluation of a high torque-to-mass, compliant actuator intended for use in future space robotics and human–
robot interaction systems. The research aligns with NASA Space Technology and Exploration Systems Development mission directorates, where
lightweight, efficient, and robust actuation is critical for planetary surface operations, in-space assembly, and astronaut-assistive robotics. The actuator
concept will emphasize mechanical efficiency and inherent compliance to reduce reflected inertia, improve shock tolerance, and enhance safety when
operating in uncertain or unstructured environments such as the lunar surface. The mentored student will explore variable speed transmission
architectures and torque-sensitive mechanisms—such as elastic elements, passive torque modulation, or mechanically adaptive gear ratios—to achieve
high output torque without relying on large, high-power motors. Design activities will include conceptual studies, analytical modeling of torque output,
efficiency, and mass, and the development of a simplified prototype. Emphasis will be placed on comparing the proposed approach to traditional fixedratio geared actuators, highlighting potential gains in energy efficiency, controllability, and operational robustness. The project will conclude with
experimental characterization and performance assessment, including measurements of torque output, efficiency, compliance behavior, and response
under variable loading conditions. Results will be evaluated in the context of NASA-relevant applications such as robotic manipulators, mobility systems,
or astronaut-assist devices, with attention to long-duration operation. Deliverables will include a technical report, design documentation, and
recommendations for future development, providing a foundation for continued research in compliant, high-performance actuators for space exploration
missions.

The student will conduct a literature and technology review (≈40–50 hours) on high torque-to-mass actuators used in space robotics, planetary mobility
systems, and human–robot interaction. This will include reviewing NASA technical reports, recent journal publications, and open-source actuator
designs. The student will summarize key design tradeoffs involving torque density, efficiency, mass, compliance, and robustness, and identify
performance gaps relative to traditional fixed-ratio geared actuators. Next, the student will perform concept development and analytical modeling (≈90–
110 hours). This work will involve selecting one actuator architecture—such as a mechanically compliant transmission, variable-speed reduction
mechanism, or torque-modulating drive—and develop a simplified analytical models to predict torque output, efficiency, reflected inertia, and compliance characteristics. The modeling tools will evaluate how design parameters influence performance and compare the proposed concept against a baseline conventional actuator. The student will then design and assemble a benchtop prototype (≈70–80 hours). This phase will include detailed CAD of
mechanical components, selection of motors, elastic elements, and transmission components, and fabrication using off-the-shelf parts and basic
machine shop or rapid prototyping tools (e.g., 3D printing). The student will develop a simple test setup to safely apply loads and measure actuator
response. Finally, the student will conduct experimental testing and performance evaluation (≈60–70 hours). Tests will quantify torque output, efficiency
under varying loads, compliance behavior, and response to torque disturbances or speed changes. Experimental results will be compared to analytical
predictions and to traditional fixed-ratio actuator performance. The project will conclude with a report and design package, including recommendations for future improvements and potential pathways toward space-relevant testing or higher-fidelity prototypes

The expected outcome of this project is a well-documented, experimentally validated proof-of-concept compliant actuator design that demonstrates
improved torque-to-mass efficiency and mechanical adaptability compared to a conventional fixed-ratio actuator. By the end of the 300-hour effort, the
student will have produced analytical models, a functional benchtop prototype, and quantitative performance data characterizing torque output, efficiency, compliance behavior, and response under variable loading conditions. The results will clarify the benefits and limitations of using variable-speed transmissions or torque-sensitive mechanisms for space-relevant robotic applications, and will identify key design tradeoffs affecting efficiency,
robustness, and controllability. The project will deliver a technical report and design artifacts suitable for informing future NASA-aligned research in
lightweight, compliant actuation for exploration, robotic manipulation, and human–robot teaming systems.