ROBOT WITH ARTICULATED OR VARIABLE LENGTH UPPER ARM

A robotic system includes a robotic arm that includes a first joint that connects a first segment to a second segment, the first segment being connected at an end of the first segment opposite the first joint to a shoulder joint of the robotic arm and the second segment being connected at an end of the second segment opposite the first joint to an elbow joint of the robotic arm; and a processor coupled to the robotic arm and configured to receive an end effector trajectory and determine a motion plan to move the end effector through the end effector trajectory, including by using the first joint to vary the distance between the shoulder joint and the elbow joint, as and if needed, to realize the end effector trajectory while using the joints and links other than the first joint in a preferred pose.