Method and device for monitoring a drive unit, especially of a window lifter, comprising a rotating drive motor

A method for monitoring an electric motor drive unit for a drivable adjusting element, to maintain a maximum allowable trapping force of the adjusting element, the method comprising:

• measuring a traveled drive path and/or a drive time of the drive unit continuously;
• determining a compensation path of the drive unit based on a temperature or a temperature-dependent first variable;
• determining a minimum change integral of a speed variable of the drive unit based on the temperature or a temperature-dependent second variable;
• determining, based on the temperature or a temperature-dependent third variable, a threshold function as a function of the drive path or the drive time, whose function values in each case represent a maximum allowable driving power and starting at a first higher threshold value, which is assigned to a first point in the starting area of the drive path or the drive time, over the course of the drive path or the drive time approach a second lower threshold value;
• determining a speed variable of the drive unit continuously and a change integral thereof;
• and
• determining continuously, after the determined compensation path is traveled and after the determined minimum change integral of the speed variable is reached, the driving power or a variable representing the driving power and monitoring the driving power or the variable representing the driving power according to the determined threshold function.