A Homography-Based Dynamic Control Approach Applied to Station Keeping of Autonomous Underwater Vehicles Without Linear Velocity Measurements

Abstract

A homography-based dynamic control approach applied to station keeping of Autonomous Underwater Vehicles (AUVs) without relying on linear velocity measurements is proposed. The homography estimated from images of a planar target scene captured by a downward-looking camera is directly used as feedback information. The full dynamics of the AUV are exploited in a hierarchical control design with inner-outer loop architecture. Enhanced by integral compensation actions and disturbance torque estimation, the proposed controller is robust with respect to model uncertainties and unknown currents. The performance of the proposed control approach is illustrated via both comparative simulation results conducted on a realistic AUV model and experimental validations on an in-house AUV.

Two-Step Adaptive Control for Planar Type Docking of Autonomous Underwater Vehicle

“…Notice that the AUV is underactuated in its sway motion. The dynamic controller in each docking step is then designed based on the dynamic models described by (12) or (13).…”

“…Given that the accurate model parameters are inaccessible, the parameter uncertainty must be considered in the controller design. In the pre-docking process, using the 3-DOF dynamic model described by (12), the model parameters are denoted by:…”

“…As there is an increasing need for executing complex tasks, the shapes and structures of AUVs are diversified for extended functions [10]. In many occasions, irregularly shaped AUVs are more preferred for close-range and high-resolution underwater observation tasks than conventional torpedo-shaped AUVs [11,12], but the corresponding docking system designs are still challenging. Most of the current irregularly shaped docking systems have complex connecting and fitting structures along with complicated docking control methods [13,14], and thus are difficult to be further extended to other system constructions.…”

“…Specifically, monocular vision is an efficient and cost-effective approach to achieve the stabilization of an AUV in front of a planar target [28]. Typical examples of the visual servo of fully actuated AUVs include the inertial-aided visual servo approach investigated in [12,29], the sliding-mode observer-based model predictive control proposed in [30] and the pipeline following application conducted in [11]. However, these methods have not yet been extended to underactuated underwater AUVs.…”

Self Calibration of a Sonar–Vision System for Underwater Vehicles: A New Method and a Dataset

“…Another example of such applications is station-keeping, which gives the ROV increased stability when standing still during inspections. This can be achieved by using homography to estimate the movement of the robot and then compensate for it [ 1 ]. Furthermore, object detection algorithms can help guide the pilot to its goal.…”