FIELD: transport engineering; automatic gear shifting in automatic and semi-automatic transmissions of vehicles with gear ratio changer operated by DC motor. SUBSTANCE: current in drive motor is controlled by microcontroller which determine whether gearshift mechanism encounters with obstacle (stops) at gearshifting, or not. Microcontroller is programmed for control of value (frequency) of voltage signals with pulse duration modulation (PDM) supplied to electric motor according to algorithm which provides proportional and differential control of difference between measured and preset currents. Quick decrease of current value under action of PDM control signal reduces force applied to gearshift mechanism and to shifting sleeve and gear of gearbox. EFFECT: improved reliability of operation. 4 cl, 6 dwg
