MEMS electrochemical angular accelerometer: a paradigm shift for attitude detection and control in rotorcraft UAVs

Angular acceleration plays a very critical role for the dynamic control of the accurate attitude estimation of the unmanned aerial vehicles (UAVs), which is conventionally acquired by the differentiation of the gyroscope signals. However, this indirect derivation inherently introduces detrimental phase lags and amplifies noise, thereby compromising the control stability of flight control systems. To address these limitations, this work proposes a MEMS-based electrochemical angular accelerometer (EAA) with high performance, enabling a direct and high-fidelity angular acceleration measurement. Through theoretical modeling and finite element optimization, a compact plate-type electrode structure that enhances hydrodynamic resistance and sensitivity was developed with Glass-on-Silicon (GOS) package. The fabricated device (22 × 22 × 25 mm³) achieves a sensitivity of 4.5 V/(rad/s²) and a noise floor of 3.12 × 10^-6 (rad/s²)/√Hz at 1 Hz, with an ultra-low power consumption of 2.4 mW. While its intrinsic bandwidth is 0.01-0.2 Hz, a compensation circuit extends the -3 dB operational response to 10 Hz. The performance of the EAA was comprehensively validated, ranging from open-loop turntable performance evaluations to flight tests employing a closed-loop incremental nonlinear dynamic inversion (INDI) controller. The results demonstrate that the EAA yields faster command responsiveness and reduced tracking errors when compared to gyroscope-derived estimates. By establishing a robust architecture for direct, low-latency measurement, this work establishes a direct sensing paradigm for high-fidelity angular acceleration measurement in UAV attitude control.