Position/force control system for unmanned underwater vehicles with manipulators in the hovering mode

Abstract

The paper proposes a control system for unmanned underwater vehicles (UUV) equipped with multilink manipulators (MM) to perform contact (position-force) operations in the hover mode over objects. This system is built on the basis of methods for ensuring the stabilization of the UUV at a given point in water with the help of thrusts created by the propellers of the vehicle. Unavoidable errors in the stabilization of the UUV emerge due to force contact of the MM working tool (WT) with the object of work. These errors are compensated by additional correction of the trajectory and orientation of the tool. As a result, the MM changes its configuration and continues to move along the surface of the object. For operations that require control of the created force, a method is additionally implemented that allows real-time creation of forces and moments by the propellers of the UUV. These forces and moments are necessary for performing manipulation operations. At the same time, the force effects of the object on the MM WT are calculated using observers in its electric drives, without requiring the installation of force-torque sensors on this tool and at the point of attachment of the MM to the UUV. Due to the simultaneous formation of force effects of MM and UUV, contact operations are ensured. The operability and efficiency of the system were confirmed using numerical simulation in Matlab/Simulink with visualization in the CoppeliaSim simulator.