Robot arm and method of its use

Abstract

An aircraft servicing system comprises four robot arms mounted to the ground so as to form a lane with the base of two of the robot arms delineating one side of the lane and the base of the other two robots delineating the other side of the lane. The robot arms may assume a low position which allows an aircraft's wings to pass over the arms while the aircraft enters the lane between the arms. Thereafter, the arms may be moved so that a nozzle array at the end of each arm may de-ice or wash the aircraft. Subsequently, the arms may again assume a low position to allow the aircraft to leave the lane. Each robot arm has an elongated member connected to the base by a yaw joint, a first arm segment connected to the elongated member by a pitch joint, second arm segment connected to the first arm segment by a pitch joint, and a third arm segment connected to the second arm segment by a telescoping joint. This gives the arm the needed range of motion and provides one degree of redundancy so that the arm has some freedom of movement while the end effector is stationary in free-space. This allows the arm to be reconfigured as necessary, on a dynamic basis, so as to anticipate possible singularities and avoid these. The system has application for servicing other large structures, such as the hull of a dry docked ship.