Method for controlling an output shaft in a drive unit

A method for controlling an angular position of an output shaft in a drive unit having a drive shaft, a drive apparatus for driving the drive shaft, and a strain wave gear for transmission from the drive shaft to the output shaft, wherein the strain wave gear has a wave generator operatively connected to the drive shaft, a flexible ring, and a toothed ring connected to the output shaft, comprising a first sensor for detecting the angular position of the output shaft and a second sensor for detecting a first torque transmitted by the flexible ring, the method comprising the steps of:

• detecting a change in a direction of the drive apparatus with respect to a prior rotation,
• detecting the first torque transmitted by the flexible ring immediately upon detection of the change in the direction by means of the second sensor,
• determining a drive period of the drive apparatus until an expected attainment of a transmission torsion of the flexible ring on a basis of the first torque,
• driving the drive shaft by means of the drive apparatus over the drive period,
• detecting a change in the angular position of the output shaft immediately after an end of the drive period by means of the first sensor, and
• controlling the drive apparatus using the first sensor following the drive period when the change in the angular position is detected.