Bases of the electromechanical systems (EMS) dynamics theory are exposed. That EMS include a wide class of electric drives of various machines and mechanisms which have slipping and skidding in normal or abnormal operating modes accompanied by self-oscillatory processes. It is shown, that the electric drive is a specific source of mechanical energy which may not only to generate self-oscillations, but also to eliminate ones, inevitable for mechanical system. The term «negative viscous friction» (NVT) is used for a «falling» section of electric drive load nonlinear mechanical characteristic by analogy with electric «negative dynamic resistance». Increasing of slipping speed at that section leads to reduction of friction factor. Dynamic modes of typical opened and closed EMS with NVT are researched, nonrelaxational frictional self-oscillations (FSO) appearance conditions are defined. Principles of electric drives control with nonlinear frictional load are specified and electromechanical systems synthesis methods (including fuzzy and neuroregulators), which eliminate nonrelaxational FSO are proposed. Quasineuroregulator providing regulation preset parameters, executed according of the elementary neuron structure, and weight factors calculation procedure are offered according developed formulas. Computer modeling confirms variety FSO forms and establishes their conformity to observable ones in real operating conditions of machines and mechanisms.
The phenomenon of amplification of elastic fluctuations by friction nonlinearity during fluctuations of normal pressure force which should be distinguished from FSO is discovered, described and explained by the author at experimental researches at the Magdebourg university Otto von Gerike.
EMS dynamics during slow movements at stick-slip conditions is investigated, and ways of task tracking accuracy increase by means of the adjustable electric drive are proposed.
The results of experimental researches confirming theoretical positions and also examples of practical design of slipping, skidding and frictional self-oscillations detection and elimination devices are resulted. Researches perspective directions in the field of electromechanical systems dynamics with nonlinear friction are specified.