Patent attributes
A method detects and prevents stall of a drive motor of an autonomous electric tractor. A stall detector receives, at intervals, a motor current value from a drive circuit of the autonomous electric tractor, determines when the motor current value reaches or exceeds a first current threshold and applies brakes, inhibits a throttle controlling the drive motor, and sets a motor stall flag. A method determines a height above the ground of a landing gear of a trailer coupled with a tractor. A lift detector controls a hydraulic pump to pump a hydraulic fluid into a chamber of a piston coupled to a fifth wheel of the tractor to raise the fifth wheel. The lift detector senses, at intervals as the fifth wheel rises, a pressure value of the hydraulic fluid in the chamber and processes the pressure value to determine when the landing gear is lifted off the ground.
