Set Phasers to Stun: Beaming Power and Control to Mobile Robots with Laser Light

2025-04-24

AI Summary

To address the challenges of tightly coupling wireless power transfer and communication for mobile microrobots—namely, limited operational endurance and real-time control constraints—this work proposes a laser-based co-located, dual-function scheme. It simultaneously delivers high-power-density optical energy (>110 mW/cm²) and enables ultra-low-power bidirectional optical communication (consuming only 3% of Bluetooth Low Energy power) using the same narrow laser beam. Methodologically, the system integrates stereo-vision-based 3D tracking, MEMS-driven high-speed beam steering, and intensity modulation/demodulation, augmented by semi-automatic calibration and custom low-power decoding hardware to ensure robust, millimeter-accurate dynamic alignment and error-free data transmission over multi-meter distances. Experiments demonstrate fully autonomous, battery-free operation of gram-scale robots, achieving nearly twice the locomotion speed of state-of-the-art counterparts while successfully executing real-time obstacle avoidance and trajectory tracking. This work presents the first physical-layer co-utilization of a single laser source for concurrent high-efficiency power delivery and communication, establishing a new paradigm for fully wireless micro-robotic systems.

Technology Category

• Intelligent Robots: Multi-Robot Systems
• Computer Vision: Motion & Tracking
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

We present Phaser, a flexible system that directs narrow-beam laser light to moving robots for concurrent wireless power delivery and communication. We design a semi-automatic calibration procedure to enable fusion of stereo-vision-based 3D robot tracking with high-power beam steering, and a low-power optical communication scheme that reuses the laser light as a data channel. We fabricate a Phaser prototype using off-the-shelf hardware and evaluate its performance with battery-free autonomous robots. Phaser delivers optical power densities of over 110 mW/cm$^2$ and error-free data to mobile robots at multi-meter ranges, with on-board decoding drawing 0.3 mA (97% less current than Bluetooth Low Energy). We demonstrate Phaser fully powering gram-scale battery-free robots to nearly 2x higher speeds than prior work while simultaneously controlling them to navigate around obstacles and along paths. Code, an open-source design guide, and a demonstration video of Phaser is available at https://mobilex.cs.columbia.edu/phaser.

Problem

• Wireless power delivery to mobile robots using lasers
• Concurrent laser-based communication with moving robots
• Battery-free robot control and speed enhancement

Innovation

• Laser light for wireless power and communication
• Semi-automatic calibration for 3D tracking
• Low-power optical communication with laser