Abstract: A monitoring method for a drive system with a motor and a moving part driven by the motor. The movement of the driven part is monitored and the movement of the driving part is monitored and compared to recognize a collision between the driven part and another structure. Measurement of at least one drive-side motion quantity of the motor is taken and measurement of at least one driven-side motion quantity of the moving part is taken. The motion quantity can be a position, velocity or acceleration. A dynamic model is calculated based on predetermined or expected operational data and the drive side measured data. An error signal is generated when the motion quantity measured on the driven side varies from the dynamic model.