Stanford Robotics Seminar ENGR319 | Spring 2026 | Mechanical Intelligence in Locomotion

The Missing Middle in Robotics

Missile-scale robots weighing approximately 1 kilogram occupy a significant research gap between micro-robots (<1g) and macro-robots (>10kg), enabling navigation of confined spaces too tight for large robots while handling obstacles too large for microscopic ones.

High-Value Application Markets

This scale is critical for CBRN threat detection (projected $21.5B market by 2028) and precision agriculture ($21.9B by 2031), allowing operations in collapsed buildings and crop fields without the damage caused by heavy machinery.

The Noise-Dominated Regime

Unlike large robots interacting with continuous media or tiny robots engaging single objects, missile-scale robots simultaneously interact with approximately 10 terrain objects of similar mass, creating unpredictable reaction forces that defy conventional control methods.

Information Theory Analogy for Locomotion

Reliable locomotion can be achieved without sensory feedback by treating steps as digital bits and utilizing morphological redundancy (multiple legs), analogous to how error-correcting codes enable reliable signal transmission over noisy channels without retransmission requests.

Redundancy Enables Guaranteed Performance

Mathematical derivation shows that with sufficient leg count, the upper and lower bounds of travel time converge to a single predictable point, guaranteeing that a robot will arrive at its destination in exactly the planned time regardless of terrain complexity.

Passive Mechanical Stability

Morphological intelligence relies on passive physical responses to perturbations governed by body design and physical laws, eliminating the need for real-time computational intelligence to navigate heterogeneous terrain.

Centipede Gait Switching Strategy

While multi-legged designs traditionally sacrifice speed for robustness, biological studies show centipedes achieve three times higher speeds on flat ground by switching to a 'terrestrial swimming' gait, demonstrating that morphology and performance have a many-to-many rather than one-to-one mapping.

Viscous-Driven Terrestrial Swimming

On flat terrain, centipedes utilize viscous-dominated locomotion characterized by a low coasting number (similar to worms) rather than inertia-driven walking, effectively swimming through terrestrial environments via coordinated body-leg movement.

Leg Count Determines Reliability

Experiments comparing 6-legged to 16-legged robots showed that while leg count minimally affects flat-ground speed, 16-legged robots maintain consistent velocity over complex terrain whereas 6-legged robots frequently get stuck, validating the redundancy theory.

Convergence of Arrival Times

Empirical data confirmed that increasing leg count substantially reduces the variance in arrival times, with the distribution converging toward a guaranteed locomotion time even in highly unstructured environments.