Stop to Decide: Latency-Aware Proprioceptive Navigation Primitives for Mapping-Free Quadruped Inspection

2026-07-13

AI Summary

This work addresses the problem of stair-top misidentification and overshooting in computationally constrained quadrupedal robots caused by navigation loop latency. The authors propose a “pause-and-decide” strategy that integrates a pause-stabilization rhythm during stair climbing, leveraging proprioceptive signals for precise top-edge detection. This approach enables the construction of map-free, learning-free navigation primitives suitable for confined-space inspection tasks. Notably, it incorporates a latency-aware pausing mechanism into a purely proprioceptive navigation stack—utilizing only an IMU, foot force sensors, a 1D rangefinder, and a line-scan camera—and achieves zero stair-overshoot incidents, 100% success in 90-degree corridor turns without collisions, and an overall mission success rate of 90% (18 out of 20 trials) under a low-frequency control loop of approximately 15 Hz.

Abstract

Compute-constrained quadrupeds often run their navigation loop far below the controller's design rate: sharing the onboard Jetson Orin with the vision pipeline slows our stair loop to about 15 Hz. This latency breaks a standard proprioceptive pattern: declaring stair-summit arrival from the body-pitch signal while still climbing. On a stepped platform whose 50 cm top is shorter than the robot (Unitree Go2, about 75 cm), in-motion detection overshoots the top edge with probability rising with the per-period advance v/f (the slowest about 15 Hz cell partly diluted by a separate non-arrival mode), whereas a climb-settle cadence holds overshoot near zero at every loop rate (pooled 22/45 vs 1/45 over about 30/20/15 Hz; Fisher p about 2.4e-7; 7/15 vs 0/15 at the deployed about 15 Hz). A logistic dose-response model in v/f captures the failure; a pre-specified 40 Hz out-of-sample test favours the protocol-clean fit (33% observed vs 43%/22% predicted), giving a deployment rule (critical loop rate about 19 Hz at 0.30 m/s). The detector sits in a fully onboard, mapping-free and learning-free stack: built-in inertial measurement unit, four foot-force channels, three 1-D ranges, one line camera, chaining line-following, a three-segment maneuver for 90-degree corners in a 55 cm corridor (20/20 contact-free vs 14/20 with 12 wall contacts for in-place yaw; exit-heading error 1.56 degrees vs 5.64 degrees), and stair traversal, completing the inspection course in 18/20 trials (90%). Results are from a single course geometry, platform, and operator.

Problem

• latency
• proprioceptive navigation
• quadruped robot
• stair traversal
• control loop rate

Innovation

• latency-aware navigation
• proprioceptive primitives
• mapping-free quadruped
• climb-settle cadence
• onboard perception