Human clock based timing improves exoskeleton gait tracking accuracy
PhaseSync-Exo: Human Clock Anchored Reference Adaptation for Dynamic Gait Tracking
Robotics
Summary
Walking with an exoskeleton requires matching the user's walking pattern closely, including their timing. The authors developed PhaseSync-Exo, a system that uses sensors and advanced algorithms to closely track and adapt to a person’s walking rhythm. This approach helps the exoskeleton keep in sync with the user's internal walking clock, reducing timing errors and making movement smoother. Their tests in simulation showed this method greatly improves timing alignment without causing sudden jumps or falls.
What this means in practice
- •For exoskeleton developers: Improve the timing accuracy and smoothness of exoskeleton gait tracking to better match users’ natural walking rhythms.$Commercial implications: Enables creation of exoskeletons with enhanced human motion synchronization, providing better user comfort and performance.
- •For rehabilitation device engineers: Design assistive devices that maintain continuous alignment to a patient’s walking phase, improving therapy outcomes and device responsiveness.
Authors
Kaijie Qi, Yuehan Wang, Kaiming Xu, Chong Li, Jiakuo Yu
Abstract
Human-aware exoskeleton walking requires reconstructing gait, tracking diverse motions under dynamic constraints, and preserving human timing. We present PhaseSync-Exo, which combines two-IMU CNN-Transformer reconstruction, factorized amplitude-cadence retargeting with curriculum-trained recurrent control, and a human-clock-anchored adapter (HCA). HCA combines human-clock attraction with robot-relative feedback to adjust reference rate while preserving forward progression and continuity. The reconstruction module achieves a mean absolute error (MAE) of 3.24 degrees on a held-out recording, and the frozen tracking policy completes 356 of 357 amplitude-frequency trials. Two complementary dynamic comparisons isolate HCA's timing benefit without retraining. Against robot-relative correction, HCA reduces human-clock phase MAE from 95.55 degrees to 10.99 degrees, limiting reference drift. When human and delivered phases initially differ, it reduces phase MAE from 72.02 degrees to 13.90 degrees versus fixed-clock continuation. Compared with immediate phase reset, HCA reduces transient reference-tracking hip RMSE by 22.7% without reference jumps. All 420 timing rollouts complete without falls. These simulation results support continuous phase acquisition and sustained alignment to an independent human clock.