On the effects of angular acceleration in orientation estimation using inertial measurement units

TL;DR

This paper investigates how angular acceleration affects orientation estimation with inertial measurement units, revealing that rotational accelerations alter filter dynamics and challenge existing algorithms, validated through experiments.

Contribution

It provides a detailed analysis of the impact of angular acceleration on filter behavior, highlighting the nonminimum phase issues and limitations of current validation methods.

Findings

Rotational accelerations introduce nonminimum phase behavior in filters.

Mahony and Madgwick filters can attenuate acceleration but reduce bandwidth.

Precollected data validation schemes may not accurately reflect real closed-loop effects.

Abstract

In this paper, we analyze the orientation estimation problem using inertial measurement units. Many estimation algorithms suffer degraded performance when accelerations other than gravity affect the accelerometer. We show that linear accelerations resulting from rotational accelerations cannot be treated as external disturbance to be attenuated, rather, they change the dynamic behavior of the filter itself. In particular, this results in the introduction of additional zeros in the linearized transfer functions. These zeros lead to nonminimum phase behavior, which is known to be challenging for control. We validate these findings experimentally. Further, we demonstrate that Mahony and Madgwick filters can attenuate the acceleration at the expense of reduced bandwidth. In addition, we show that validation schemes based on precollected data fail to capture these closed-loop effects accurately.