Patent ID: 7193381

Claim:
An electric jack ground contact detection device for detecting ground contact of an electric motor-driven jack as the jack is being extended to adjust the attitude of a mobile platform, the device comprising: a controller configured to: monitor the electrical power draw of an electric motor-driven jack while the jack is being extended for use in adjusting the attitude of a mobile platform; recognize jack ground contact when the monitored power draw value exceeds a ground contact power draw value consistent with jack ground contact; and calculate the ground contact power draw value as equaling the sum of a dynamically-adjusted threshold power draw value associated with jack extension before ground contact and a power draw increase value equaling an amount of additional power that the jack is known to draw as a result of jack ground contact; and a jack motor power draw sensor connected to the controller and configured to sense electrical power drawn by a jack motor and to transmit a corresponding jack motor power draw feedback signal to the controller.