A door drive device for adjusting and/or locking a vehicle door relative to a vehicle body, the door drive device comprising: - an adjustment member, - a drive element operatively coupled to the adjustment member such that the adjustment member is movable with respect to the drive element for moving the vehicle door relative to the vehicle body, - a sensor device for measuring a measuring quantity indicative of a movement of the vehicle door to provide a sensor signal, and - a control device for controlling operation of the door drive device, wherein the control device is configured to compute, from said sensor signal obtained from the sensor device, an acceleration value indicative of an acceleration of the vehicle door, wherein the control device is further configured to evaluate said acceleration value to distinguish a moving of the vehicle door caused by a gravity force and a moving of the vehicle door caused by a user action, characterized in that the control device is configured to evaluate whether said acceleration value is substantially constant over a predetermined period of time or a predetermined period of position, wherein the control device is configured to compute, from said sensor signal obtained from the sensor device, a speed value indicative of a moving speed of the vehicle door, wherein the control device is configured to evaluate said speed value to distinguish a moving of the vehicle door caused by a gravity force and a moving of the vehicle door caused by a user action, wherein the control device is configured to initiate a braking of a movement of the vehicle door in case said acceleration value is detected to be substantially constant over said predetermined period of time or said predetermined period of position and in addition based on a comparison of said speed value to a predefined upper speed threshold. - an adjustment member, - a drive element operatively coupled to the adjustment member such that the adjustment member is movable with respect to the drive element for moving the vehicle door relative to the vehicle body, - a sensor device for measuring a measuring quantity indicative of a movement of the vehicle door to provide a sensor signal, and - a control device for controlling operation of the door drive device, wherein the control device is configured to compute, from said sensor signal obtained from the sensor device, an acceleration value indicative of an acceleration of the vehicle door, wherein the control device is further configured to evaluate said acceleration value to distinguish a moving of the vehicle door caused by a gravity force and a moving of the vehicle door caused by a user action, characterized in that the control device is configured to evaluate whether said acceleration value is substantially constant over a predetermined period of time or a predetermined period of position, wherein the control device is configured to compute, from said sensor signal obtained from the sensor device, a speed value indicative of a moving speed of the vehicle door, wherein the control device is configured to evaluate said speed value to distinguish a moving of the vehicle door caused by a gravity force and a moving of the vehicle door caused by a user action, wherein the control device is configured to initiate a braking of a movement of the vehicle door in case said acceleration value is detected to be substantially constant over said predetermined period of time or said predetermined period of position and in addition based on a comparison of said speed value to a predefined upper speed threshold.