A drive unit for a robot, having an input shaft, an input shaft drive motor and a strain wave gear mechanism for transmission to an output shaft. The strain wave gear mechanism has a wave generator which is operatively connected to the input shaft, a flexible ring and a toothed ring are connectable to the output shaft, a first sensor for detecting an angular position of the input shaft and a second sensor for detecting the angular position of the output shaft. In order to allow the drive unit to precisely adjust the angular position of the output shaft to each setpoint angular position, the drive unit has a third sensor for detecting an expansion of the flexible ring. A robot having such a drive unit and a method for precisely adjusting the angular position of the output shaft are also provided.

A drive unit for a robot, having an input shaft, an input shaft drive motor and a strain wave gear mechanism for transmission to an output shaft. The strain wave gear mechanism has a wave generator which is operatively connected to the input shaft, a flexible ring and a toothed ring are connectable to the output shaft, a first sensor for detecting an angular position of the input shaft and a second sensor for detecting the angular position of the output shaft. In order to allow the drive unit to precisely adjust the angular position of the output shaft to each setpoint angular position, the drive unit has a third sensor for detecting an expansion of the flexible ring. A robot having such a drive unit and a method for precisely adjusting the angular position of the output shaft are also provided.