A method of positional-force control of an underwater manipulator

Vladimir Fedorovich Filaretov; Aleksandr Valer'evich Zuev; Aleksandr Alekseevich Timoshenko; Igor Vyachwslavovich Gornostaev; Yunli Nie

Vladimir Fedorovich Filaretov Institute of Automation and Control Processes FEB RAS http://orcid.org/0000-0001-8900-8081
Aleksandr Valer'evich Zuev Institute of Automation and Control Processes FEB RAS http://orcid.org/0000-0002-0934-6222
Aleksandr Alekseevich Timoshenko M.D. Ageev Institute of Marine Technology Problems FEB RAS http://orcid.org/0000-0003-1356-9602
Igor Vyachwslavovich Gornostaev Institute of Automation and Control Processes FEB RAS http://orcid.org/0000-0002-4102-3511
Yunli Nie College of Ocean Science and Engineering https://orcid.org/0000-0002-4102-3511

Keywords: underwater manipulator, autonomous underwater vehicle, control system, positional-force control

Abstract

The article is devoted to solving the problem of developing a method for constructing positional-force control systems for electric drives (ED) of multi-link underwater manipulators (UM) mounted on autonomous underwater vehicles operating in the mode of landing on the ground or on work sites. To solve this problem, a comprehensive method is proposed. First, for an ED of each degree of freedom of the UM, a self-adjusting correction device is constructed, which makes it possible to stabilize the variable dynamic parameters of this ED at a given nominal level. This stabilization compensates for the influence of Coulomb and viscous frictions, the interactions between the UM links and influence of a viscous medium, on the quality of control. Then, for each ED sliding observers are constructed, which make it possible to obtain information about the current values of the external torques, speeds and accelerations of rotation of the output shafts of all ED. Using this information and measurements of only position sensors of the specified ED, it is possible to construct position-force regulators for them that minimize the selected quadratic cost function. This minimization makes it possible to ensure not only the precise movement of the UM tool along specified spatial trajectories in the presence of significant impacts from the viscous medium, but also to create the required force effects on underwater work objects when performing various technological operations. The operability and effectiveness of the constructed positional-force control systems is confirmed by the results of computer modeling.