Design Differences between Robotic Manipulators and Construction Equipment

Robotic manipulators and construction equipment come from different traditions that have different objectives. The differences impede use of robotics in construction and use of construction technology in robotics. Robots come from the machine tool tradition where the objective is to hold the position of a tool independent of the forces on it, allowing repetitive production of uniform parts despite differences in stock. The objective of construction equipment is to augment human strength, e.g., to move heavy loads over uneven surfaces. Robotic manipulators have bulky, rigid limbs, the result of designing to put natural mode frequencies above the control system roll off, so that the control system will not respond to the vibration. The typical maximum payload-to-weight ratio of a robotic manipulator is only about 1:20 far too low for a crane. Construction equipment is designed to be rugged rather than rigid; thus, some bending of a boom or flexing of an outrigger is acceptable. An understanding of the fundamental differences between machine tools and construction equipment can show where improvement would benefit both technologies.