Automatically steering a mobile machine

A method for automatically steering a tractor with a track-type system to follow a grade line, comprising:

• automatically steering the tractor in a track steering mode, wherein the tractor includes a cabin, a left track, a right track, and a blade positioned forward of the cabin, the left track, and the right track;
• initiating a blade steering mode based on a load condition of the tractor, wherein the load condition of the tractor is based on a measured load on the blade;
• and
• calculating a normalized pull weight of the tractor based on the load condition of the mobile machine;
• comparing the normalized pull weight to a dual steering mode initiation value;
• and
• automatically steering the tractor in the track steering mode and the blade steering mode, simultaneously, to follow the grade line based on the load condition of the tractor and based on the comparison between the normalized pull weight and the dual steering mode initiation value.

A system for automatically steering a mobile machine in both a track steering and blade steering mode, simultaneously, the system comprising:

• a cabin;
• a left track and a right track;
• a blade positioned forward of the cabin, the left track, and the right track in a direction of forward travel of the mobile machine;
• a sensor system configured to measure a load on the blade;
• a steering module that receives an input from an automatic steering control switch;
• and
• a controller configured to:
• automatically steer the mobile machine in a track steering mode;
• initiate a blade steering mode based on a load condition of the mobile machine based on the measured load on the blade;
• and
• calculate a normalized pull weight of the mobile machine based on the load condition of the mobile machine;
• compare the normalized pull weight to a dual steering mode initiation value;
• and
• automatically steer the mobile machine in the track steering mode and the blade steering mode, simultaneously, based on the load condition of the mobile machine and based on the comparison between the normalized pull weight and the dual steering mode initiation value.