arXiv subjects

William H. Reinhardt

Publications and source records attributed to William H. Reinhardt.

3 recordsLinked to original sources

arXiv2025

Microscopic Robots That Sense, Think, Act, and Compute

While miniaturization has been a goal in robotics for nearly 40 years, roboticists have struggled to access sub-millimeter dimensions without making sacrifices to on-board information processing due to the unique physics of the microscale. Consequently, microrobots often lack the key features that distinguish their macroscopic cousins from other machines, namely on-robot systems for decision making, sensing, feedback, and programmable computation. Here, we take up the challenge of building a microrobot comparable in size to a single-celled paramecium that can sense, think, and act using onboard systems for computation, sensing, memory, locomotion, and communication. Built massively in parallel with fully lithographic processing, these microrobots can execute digitally defined algorithms and autonomously change behavior in response to their surroundings. Combined, these results pave the way for general purpose microrobots that can be programmed many times in a simple setup, cost under $0.01 per machine, and work together to carry out tasks without supervision in uncertain environments.

cs.RO↗

arXiv2025

Artificial Spacetimes for Reactive Control of Resource-Limited Robots

Field-based reactive control provides a minimalist, decentralized route to guiding robots that lack onboard computation. Such schemes are well suited to resource-limited machines like microrobots, yet implementation artifacts, limited behaviors, and the frequent lack of formal guarantees blunt adoption. Here, we address these challenges with a new geometric approach called artificial spacetimes. We show that reactive robots navigating control fields obey the same dynamics as light rays in general relativity. This surprising connection allows us to adopt techniques from relativity and optics for constructing and analyzing control fields. When implemented, artificial spacetimes guide robots around structured environments, simultaneously avoiding boundaries and executing tasks like rallying or sorting, even when the field itself is static. We augment these capabilities with formal tools for analyzing what robots will do and provide experimental validation with silicon-based microrobots. Combined, this work provides a new framework for generating composed robot behaviors with minimal overhead.

cs.RO↗

arXiv2024

Electrokinetic Propulsion for Electronically Integrated Microscopic Robots

Semiconductor microelectronics are emerging as a powerful tool for building smart, autonomous robots too small to see with the naked eye. Yet a number of existing microrobot platforms, despite significant advantages in speed, robustness, power consumption, or ease of fabrication, have no clear path towards electronics integration, limiting their intelligence and sophistication when compared to electronic cousins. Here, we show how to upgrade a self-propelled particle into an an electronically integrated microrobot, reaping the best of both in a single design. Inspired by electrokinetic micromotors, these robots generate electric fields in a surrounding fluid, and by extension propulsive electrokinetic flows. The underlying physics is captured by a model in which robot speed is proportional to applied current, making design and control straightforward. As proof, we build basic robots that use on-board circuits and a closed-loop optical control scheme to navigate waypoints and move in coordinated swarms at speeds of up to one body length per second. Broadly, the unification of micromotor propulsion with on-robot electronics clears the way for robust, fast, easy to manufacture, electronically programmable microrobots that operate reliably over months to years.

cs.RO↗