Relative Pose Estimation for Nonholonomic Robot Formation with UWB-IO Measurements (Extended version)
For multi-robot formation control, this work solves the practical problem of aligning sensor measurements in a common frame, which is a known bottleneck for nonholonomic robots.
This paper addresses distributed formation control for nonholonomic robots using only UWB distance and inertial odometer measurements, without requiring a common reference frame. The proposed method achieves relative pose estimation in a local frame and demonstrates effectiveness through real-world 3D and 2D experiments.
This article studies the problem of distributed formation control for multiple robots by using onboard ultra wide band (UWB) distance and inertial odometer (IO) measurements. Although this problem has been widely studied, a fundamental limitation of most works is that they require each robot's pose and sensor measurements are expressed in a common reference frame. However, it is inapplicable for nonholonomic robot formations due to the practical difficulty of aligning IO measurements of individual robot in a common frame. To address this problem, firstly, a concurrent-learning based estimator is firstly proposed to achieve relative localization between neighboring robots in a local frame. Different from most relative localization methods in a global frame, both relative position and orientation in a local frame are estimated with only UWB ranging and IO measurements. Secondly, to deal with information loss caused by directed communication topology, a cooperative localization algorithm is introduced to estimate the relative pose to the leader robot. Thirdly, based on the theoretical results on relative pose estimation, a distributed formation tracking controller is proposed for nonholonomic robots. Both 3D and 2D real-world experiments conducted on aerial robots and grounded robots are provided to demonstrate the effectiveness of the proposed method.