Smooth and Robust Trajectory Tracking of Single-Actuator Monocopters Via Incremental Nonlinear Dynamic Inversion
Emmanuel Tang, Xinyu Cai, SHAWNDY MICHAEL LEE, Shaohui Foong
AI summary
Problem
Single-actuator monocopters (SAMs) face strong precession and gyroscopic coupling that make aggressive trajectory tracking difficult, while existing control methods suffer from poor disturbance rejection and large tracking errors.
Approach
The authors apply Incremental Nonlinear Dynamic Inversion (INDI), which uses real-time angular acceleration measurements to incrementally compensate for unmodeled dynamics and precession, benchmarked against standard NDI and attitude control across different wing morphologies.
Key results
- INDI reduces mean angular acceleration tracking error by up to 13.8% compared to NDI
- INDI decreases motor PWM usage by up to 8.4%, improving actuator efficiency
- INDI achieves up to 65% improvement in 3D position tracking over traditional attitude control
- INDI maintains robust tracking performance under severe actuation constraints with ultralight-wing configurations
Why it matters
Provides a robust, sensor-reliant control framework that enables reliable and efficient aggressive flight for mechanically simple, single-actuator aerial robots.
Abstract
This letter presents a comprehensive comparative study of Incremental Nonlinear Dynamic Inversion (INDI) and standard Nonlinear Dynamic Inversion (NDI) for smooth trajec- tory tracking on Samara Seed-Inspired Single-Actuator Mono- copters (SAM). While prior work on SAMs has largely focused on hover stabilization, smooth robust control for aggressive trans- lational motion remains a largely uncharted frontier. Leveraging the precession-prone dynamics inherent to the SAM, we analyze the tracking performance of INDI across varying flight speeds, trajectories, and wing morphologies (long, short, ultralight). Our experiment results demonstrate that INDI on the long-wing con- sistently achieves lower angular acceleration tracking errors, re- ducing mean and RMS by up to 13.8% and 13.0%, respectively, while also improving motor efficiency with up to 8.4% less PWM usage compared to NDI. Additionally, INDI produces tighter and more stable body yaw rates (± 0.1 Hz) and delivers up to 65% improvement in position tracking over traditional purely attitude control(ATT).Finally,evenundersevereactuationconstraintswith an ultralight-wing operating at reduced thrust, INDI maintains robust performance, validating its resistance towards precession and robust control of highly under-actuated SAMs.