Active Use of Restoring Moments for Motion Control of an Underwater Vehicle-Manipulator System

Abstract

This paper proposes a framework for actively using the restoring moments of an underwater vehicle-manipulator system (UVMS) considering both kinematic and control aspects. The kinematic aspect concerns redundancy resolution of the UVMS where the redundant degrees of freedom are used to selectively optimize the restoring moments. For this, a performance index with variable gradient gain is newly proposed, in which the gain is determined by the result in the comparison of the task direction with the direction of the restoring moments. The control aspect concerns compensation of the restoring forces and moments. In this framework, the control input makes up for the difference between the performances due to the desired dynamics and the restoring moments. This is accomplished by compensation of the restoring forces and moments, which are consistently updated under certain constraints. In addition, the compensation and optimal proportional-integral-derivative (PID) control are merged into a robust adaptive control. The proposed framework requires only masses, buoyant forces, and centers of gravity and buoyancy, not any hydrodynamic parameters. Numerical simulations are presented to demonstrate the performance of the proposed framework, in which a UVMS can perform specific tasks with less control input and achieve smaller tracking errors compared to conventional control systems.Index Terms-Redundancy resolution, robust adaptive control, underwater vehicle-manipulator system (UVMS).

Approximation grid evaluation-based PID control in cascade with nonlinear gain

“…This can be done in open-or closed-loop structure, by deliberately injecting some stimulus or simply relying on the excitation provided by standard maneuvers like set point changes, and in a number of different ways, see e.g., the discussions in studies such as [5] and the references therein. In general, different values of these parameters are expected to develop an optimal strategy either as operating condition or dynamics of the system vary [6] or at different phases of control process [7], [8], [9]. Current PID control modules provide "tuning on demand" with upset [10].…”

Uncalibrated Visual Servoing for Underwater Vehicle Manipulator Systems with an Eye in Hand Configuration Camera

“…Although some previous works utilize the GPM to optimize restoring moments for UVMSs [32][33][34], there are two main differences. One is the Jacobian matrix in [32][33][34] is used to describe the velocity relationship between the configuration space and the Cartesian space (i.e., the Jacobian matrix in (27)), rather than the Jacobian matrix described in (26). The other one is previous works [32][33][34] all depend on the accurate Jacobian matrix, rather than the estimated Jacobian matrix.…”

Towards autonomy in ROV operations

“…Another option is the one of Han et al (2014) who propose a more model independent approach, namely a framework for actively using restoring moments requiring only masses, buoyancy forces and centers' of gravity, and reducing the need to identify all parameters in the equations of motion.…”