An Algorithm for Rigid-Body Angular Velocity and Attitude Estimation Based on Isotropic Accelerometer Strapdowns

Ting Zou,Jorge Angeles

doi:10.1115/1.4039435

Abstract

A novel algorithm for the estimation of rigid-body angular velocity and attitude—the most challenging part of pose-and-twist estimation—based on isotropic accelerometer strapdowns, is proposed in this paper. Quaternions, which employ four parameters for attitude representation, provide a compact description without the drawbacks brought about by other representations, for example, the gimbal lock of Euler angles. Within the framework of quaternions for rigid-body angular velocity and attitude estimation, the proposed methodology automatically preserves the unit norm of the quaternion, thus improving the accuracy and efficiency of the estimation. By virtue of the inherent nature of isotropic accelerometer strapdowns, the centripetal acceleration is filtered out, leaving only its tangential counterpart, to be estimated and updated. Meanwhile, using the proposed integration algorithm, the angular velocity and the quaternion, which are dependent only on the tangential acceleration, are calculated and updated at appropriate sampled instants for high accuracy. This strategy, which brings about robustness, allows for relatively large time-step sizes, low memory demands, and low computational complexity. The proposed algorithm is tested by simulation examples of the angular velocity and attitude estimation of a free-rotating brick and the end-effector of an industrial robot. The simulation results showcase the algorithm with low errors, as estimated based on energy conservation, and high-order rate of convergence, as compared with other algorithms in the literature.

Highlights

Estimation of rigid-body twist and pose is a recurrent need in modern applications, involving air- and spacecraft, driverless automobiles and robots
The proposed estimation algorithm is tested with an example of the angular velocity and attitude estimation of a free rotating brick and the end-effector of an industrial robot
5 Conclusions The authors proposed a novel algorithm for the estimation of rigid-body angular velocity and attitude using isotropic accelerometer strapdowns, based on unit-quaternion integration

Summary

Introduction

Estimation of rigid-body twist (point-velocity and angular velocity) and pose (point position and attitude) is a recurrent need in modern applications, involving air- and spacecraft, driverless automobiles and robots. In this paper the authors propose a novel estimation algorithm, based on an innovative isotropic accelerometer strapdown design, for the angular velocity and attitude estimation of a rigid body Within this methodology, the quaternion at each time step is not obtained via a Taylor expansion, i.e., the addition or subtraction of quaternions at the previous time steps, but use direct quaternion-multiplication rules. Based on the isotropic accelerometer strapdown, the proposed estimation algorithm provides a straightforward approach to determining the angular acceleration, angular velocity and rigid-body attitude. The proposed estimation algorithm provides a straightforward approach to determining the angular velocity and attitude of the rigid body using the unit quaternion multiplication at appropriate time intervals.

Coping with Noise

Simulation Results and Discussion

Free-rotating brick

Conclusions