Tracked Vehicle Motion Correction

A self-propelled working machine (100), comprising:

• an undercarriage (122) supported by first and second ground engaging units (124 and 126);
• a main frame (132) supported by the undercarriage;
• a first sensor (170) configured to provide signals (170S) corresponding to an orientation and relative angular motion of the main frame with respect to the undercarriage;
• a second sensor (172) coupled in association with the main frame, and configured to provide signals (172S) corresponding to an orientation and relative angular motion of the main frame in an external reference frame independent of the undercarriage;
• and
• means for driving the first and second ground engaging units according to an intended orientation and relative angular motion of the undercarriage in the external reference frame, responsive to the signals from the first and second sensors.

A method (400) of controlling a working machine (100), the working machine including an undercarriage (122) supported by first and second ground engaging units (124 and 126), first and second drive units (128 and 130) for driving the first and second ground engaging units, respectively, and a main frame (132) supported by the undercarriage, the method comprising:

• detecting (402) an orientation and relative angular motion of the main frame relative to the undercarriage;
• detecting (404) an orientation and relative angular motion of the main frame in an external reference frame independent of the undercarriage;
• receiving (406) commands (114S) corresponding to an intended movement of the first and second ground engaging units;
• and
• generating (408) control signals (128S and 130S) to the first and second drive units to achieve or maintain the intended movement of the first and second ground engaging units, further accounting for a detected orientation of the main frame relative to the undercarriage and a detected orientation of the main frame in the external reference frame independent of the undercarriage.