Localization and Tracking Control of Autonomous Vehicles in Time-Varying Bearing Formation

Abstract

This letter proposes an observer-based formation tracking control approach for multi-agent velocitycontrolled vehicles under the assumption that either relative or global position measurements are unavailable for all the vehicles. It is assumed that only some vehicles (at least one) have access to their own global position, and all vehicles are equipped with sensors capable of sensing the bearings relative to neighboring vehicles. Each vehicle estimates its global position using relative bearing measurements and estimates of neighboring vehicles received over a communications network. Then, a distributed outputfeedback observer-based controller is designed relying on bearing measurements and the estimated global positions. In contrast with the literature on bearing-based localization and control, we relax the common assumption of so-called bearing rigidity, and, in addition, we do not assume that the interconnections are constant. To the best of our knowledge, the bearing-based localization-and-tracking control problem under such assumptions remains open. In support of our theoretical findings, some simulation results are presented to illustrate the performance of the proposed observer-based tracking controllers.

Leader-follower bearing-based distributed pose estimation for multi-vehicle networks

“…Recently, the latter category is gaining in popularity because of the revolutionary development in bearing sensors. As a result, several bearing-based distributed position estimation solutions have been proposed in the literature [1], [2], [3], [4]. However, the aforementioned references assume that the bearings are expressed in a global reference frame (i.e., knowledge of agents' orientations with respect to a global reference frame), which, unfortunately, is not the case in most of the practical applications since the bearing measurements are usually obtained locally from a sensor (e.g., a camera) mounted on the agent.…”

“…For any R ∈ SO(3), the normalized Euclidean distance on SO(3), with respect to the identity I 3 , is defined as 2 , where v ∈ S 2 and θ ∈ R are the rotation axis and angle, respectively. The orthogonal projection map P : R 3 → R 3×3 is defined as…”

Relative Displacement Measurement Based Affine Formation Tracking Control for Nonholonomic Kinematic Agents

“…A few studies have focused on generating and tracking time-varying inter-agent bearings in multi-agent systems. Tang et al investigated a new type of formation based on the persistence of excitation (PE) to relax the classical bearing rigidity conditions on the graph topology and achieve the generation and tracking for time-varying interagent bearings, which is called bearing persistently exciting (BPE) formation [18]- [21]. Distributed control laws based on time-varying bearing measurements were designed under the assumption that the desired formation is BPE.…”

“…The work in [25] considered the self-localization and formation control task for single-integrator agents with bearingonly measurements, but theoretical analysis on the stability of the coupled system was not provided. In [21], bearing-based localization and formation tracking methods were proposed under the assumption that the desired formation is BPE, but the agents in this study are single integrators.…”

“…In this paper, we propose a bearing-based distributed localization algorithm to estimate global positions, which is utilized to devise control inputs for unicycle-type agents to track the desired time-varying formation, different from [21], [25], where single-integrator dynamics were considered, also from [14]- [16], where the desired inter-agent bearings are constant. The main contributions of this paper are summarized as follows:…”