Modeling and Optimization of Compensating Oil Viscous Power for a Deep-Sea Electric Manipulator

Abstract

The dynamic performance and load capacity of a deep-sea electric manipulator are obviously affected by the viscous resistance of compensating oil. However, the complex geometric clearance of the oil-filled joint of the manipulator makes it difficult for existing theoretical models to accurately model this problem. Based on the existing theoretical models, a viscous power model considering the influence of the surface grooves of the rotor and stator is proposed. To reduce the viscous power loss, an optimization method for the clearance geometry is proposed. This optimization method is carried out by filling the surface grooves of the motor rotor and stator with epoxy resin. This method makes the clearance geometry of the compensated oil more regular. The modified model and optimization method are validated by designing an experimental installation and method. The experimental results demonstrate the accuracy and effectiveness of the modified theoretical model and optimization method.INDEX TERMS Compensating oil viscous power, deep-sea electric manipulator, modified modeling, viscous power experiment, viscous power optimization.

Dexterity Based Viscous Resistance Optimization of a Deep-Sea Manipulator

“…where I represents the reduction ratio vector, η represents the efficiency vector, τ M represents the motor output torque, and τ V represents the viscous resistance. The modelling method of the viscous resistance τ V has been studied and verified in previous work [30]. By substituting Equation ( 4) into (2), the complete dynamic model of the deep-sea electric manipulator is established as…”

Prescribed Performance Non-Singular Fast Terminal Sliding Mode Control Based on Extended State Observer for a Deep-Sea Electric Oil-Filled Joint Actuator

“…Many researchers have studied the cause and change rules of the oil stirring viscos loss. The impact of oil type and motor structure on the oil stirring viscos loss was studied in [7]. The influence of temperature and pressure on the change rules of the oil stirring viscos loss was observed in [8].…”

“…Owing to the extremely high pressure in the deep-sea environment, the electric underwater manipulator is watertight and oil compensated from bearing the deep-sea water pressure [6,7]. The oil-filled joint actuator of electric underwater manipulator, which is commonly composed of a brushless, direct-drive motor with reduction gearbox featuring low backlash and a large reduction ratio [3], will suffer from oil stirring loss [7][8][9][10] resulting from the rotation viscos between the high speed rotor and oil, output shaft dynamic seal loss [10] deriving from the high-pressure action and high-speed rotation friction on the rubber seal rings, and core loss [9,10] caused by the high-pressure action on the motor cores. Therefore, the oil-filled joint actuator will show different characteristics and response performance compared with its common use.…”