Modular Underwater Robots: Modeling and Docking Control

This paper investigates the problem of employing reconfigurable robots in an underwater setting. The main results presented is the experimental validation of a modelling methodology for a system consisting of N dynamically connected robots with heterogeneous dynamics. Two distinct types of experiments are performed, a series of hydrostatic free-decay tests and a series of open-loop trajectory tests. The results are compared to a simulation based on the modelling methodology. The modelling methodology shows promising results for usage with systems composed of reconfigurable underwater modules. The purpose of the model is to enable design of control strategies for cooperative reconfigurable underwater systems.

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Validation of multi-body modelling methodology for reconfigurable underwater robots

This paper describes a modeling approach to compute the lumped parameter hydrodynamic derivative matrices of an underwater multi-hull vehicle. The vehicle, modeled as a multi-body underwater system and denoted as cluster, can be composed by heterogeneous bodies with known dynamic parameters, rigidly connected. The nonlinear dynamic equations of the cluster and its parameters are derived by means of a modular approach, based on the composition of single basic elements. The ultimate objective is to derive a mathematical description of the multi-hull system that captures its most significant dynamics allowing to design model-based motion controllers and navigation filters. The modular nature of the resulting model can be exploited, by example, when control reconfiguration is to be dealt with in the presence of (possibly multiple) failures. The numerical simulation of a hypothetical cluster is presented and discussed.

Dynamic Modeling of Underwater Multi-Hull Vehicles

Preliminary results of a dynamic modelling approach for underwater multi-hull vehicles

We propose an improved Kane dynamic model theory for the 7-DOF modular robot in this paper, and the model precision is improved by the improved function . We designed three types of progressive modular joints for reconfigurable modular robot that can be used in industrial robot, space robot, and special robot. The Kane dynamic model and the solid dynamic model are established, respectively, for the 7-DOF modular robot. After that, the experimental results are obtained from the simulation experiment of typical task in the established dynamic models. By the analysis model of error, the equation of the improved torque is derived and proposed. And the improved Kane dynamic model is established for the modular robot that used . Based on the experimental data, the undetermined coefficient matrix is five-order linear that was proved in 7-DOF modular robot. And the explicit formulation is solved of the Kane dynamic model and can be used in control system.

/pdf/establishing-an-improved-kane-dynamic-model-for-the-7-dof-57nr6am9nq.pdf

Establishing an Improved Kane Dynamic Model for the 7-DOF Reconfigurable Modular Robot

The paper presents a detailed methodology for dynamic modeling of ROV with a robotic manipulator using Kane's dynamic equations. This methodology allows construction of the dynamic model simply and incrementally. The generalized active forces and the generalized inertia forces were deduced. The forces which contribute to dynamics were determined by Kane's approach. The model developed in this paper includes inertia force, gravity, buoyancy, control inputs and two major hydrodynamic forces: added mass, profile drag. The equations of hydrodynamic forces were deduced. The methodology provides a direct method for incorporating external environmental forces into the model. The resulting model is obtained in closed form. It is computationally efficient and provides physical insight as to what forces really influence the system dynamics. The dynamic model provides a framework for modern model-based control schemes.

Yang Ke

Papers

A Dynamic Model of ROV with a Robotic Manipulator Using Kane's Method