A New Tightly-Coupled Dual-VIO for a Mobile Manipulator With Dynamic Locomotion

This article introduces a new dual monocular visual-inertial odometry (dual-VIO) strategy for a mobile manipulator operating under dynamic locomotion, i.e., coordinated movement involving both the base platform and the manipulator arm. Our approach has been motivated by challenges arising from inaccurate estimation due to coupled excitation when the mobile manipulator is engaged in dynamic locomotion in cluttered environments. The technique maintains two independent monocular VIO modules, with one at the mobile base and the other at the end-effector, which are tightly coupled at the low level of the factor graph. The proposed method treats each monocular visual-inertial odometry (VIO) with respect to each other as a positional anchor through arm-kinematics. These anchor points provide a soft geometric constraint during the VIO pose optimization. This allows us to stabilize both estimators in case of instability of one estimator in highly dynamic locomotions. The performance of our approach has been demonstrated through extensive experimental testing with a mobile manipulator tested in comparison to running dual VINS-Mono in parallel. We envision that our method can also provide a foundation toward active-simultaneous localization and mapping with a new perspective on multi-VIO fusion and system redundancy.