The Secret to Marathon-Winning Humanoid Robots

2026-06-17 · Source: IEEE Spectrum · Field: Technology & Digital — Robotics & Autonomous Systems, Artificial Intelligence & Machine Learning · Depth: Advanced, medium

Summary

On April 19, 2026, the Honor Lightning humanoid robot completed a half-marathon in 50 minutes and 26 seconds, surpassing the human world record by 7 minutes and the previous robot best by almost two hours. This performance was achieved through specific engineering optimizations rather than novel technology. Key factors include a drivetrain with a gear ratio (e.g., 45:1) specifically chosen for high-speed running at 7 m/s, which minimizes power consumption to approximately 400W and knee motor heat dissipation to ~150W. Crucially, the robot incorporates an advanced liquid-cooling system with capillary pipes and a high-power pump providing a heat-exchange flow rate exceeding 4 liters per minute, enabling sustained operation. In contrast, robots optimized for walking (e.g., 30:1 gearing for 1.5 m/s) would dissipate over 300W in knee motors during running, leading to overheating. The article also notes the trade-offs involved, as a running-optimized design is less efficient for walking.

Key takeaway

For Robotics Engineers designing legged systems aiming for peak performance in specialized tasks, you must prioritize task-specific optimizations like gear ratios and advanced thermal management. Evaluate your robot's primary use case to inform these critical engineering trade-offs. A running-optimized design requires a specific gear ratio (e.g., 45:1) and robust liquid cooling for sustained high power output. However, this will compromise efficiency for other activities like walking.

Key insights

Optimal robot performance for specific tasks like marathon running relies on task-specific engineering trade-offs, particularly in gearing and thermal management.

Principles

• Robot drivetrain gearing must be optimized for specific tasks.
• Sustained high-power output requires advanced thermal management.
• Engineering involves inherent trade-offs between specialized and versatile designs.

Method

Optimize motor gear ratios based on target speed (e.g., 45:1 for 7 m/s running) to minimize power consumption and integrate high-flow liquid cooling for sustained thermal dissipation.

In practice

• Design specific gear ratios for robot's primary function.
• Implement liquid cooling for high-power, sustained operations.
• Balance specialized performance against general versatility.

Topics

• Humanoid Robotics
• Robot Locomotion
• Gear Ratio Optimization
• Liquid Cooling
• Thermal Management
• Performance Engineering

Best for: Robotics Engineer, AI Engineer, AI Scientist

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Editorial summary, takeaway, and curation by AIssential. Original article published by IEEE Spectrum.