Robot, drive unit for a robot and positioning method

A method for adjusting an angular position of an output shaft positioned by a drive motor via a drive shaft and a strain wave gear mechanism in of a drive unit, the method comprising:

• providing the drive unit having the strain wave gear mechanism for transmission from the drive shaft to the output shaft, the strain wave gear mechanism having a wave generator operatively connected to the drive shaft, a flexible ring including a radially extending collar fixed to a housing of the drive unit, and a toothed ring that is connectable to the output shaft, a first sensor arranged on the drive shaft and configured for detecting an angular position of the drive shaft, a second sensor arranged on the toothed ring and configured for detecting an angular position of the output shaft, and a third sensor arranged on the collar and configured for detecting an expansion of the flexible ring;
• using a calibration method for determining angular distances of the drive shaft and the output shaft by the first, the second, and the third sensors at an acceleration over which there is a non-linear relationship between the angular position of the drive shaft and the angular position of the output shaft due to the expansion of the flexible ring;
• and
• using a positioning method and adjusting the angular position of the output shaft from an actual angular position to a target angular position with the second sensor as an actual value generator, and checking whether there is at least the determined angular distance of the output shaft between the actual angular position and the target angular position, and if this is not the case, rotating the output shaft until the actual angular position is spaced apart from the target angular position by at least the determined angular distance of the output shaft, and then adjusting the actual angular position to the target angular position using the second sensor.

A drive unit for a robot, the drive unit comprising:

• a drive motor having a drive shaft;
• a strain wave gear mechanism having a wave generator connected to the drive shaft, a toothed ring connected to an output shaft, and a flexible ring mounted opposite the wave generator by a ball bearing and between the wave generator and the toothed ring, wherein the flexible ring includes a radially extending collar which is fixed to a housing of the drive unit;
• a first sensor for detecting an angular position of the drive shaft;
• a second sensor for detecting an angular position of the output shaft;
• and
• a third sensor for detecting an expansion of the flexible ring.