Abstract: Electronic and information technologies have been rapidly developed since the third industrial revolution. Conventionally, machines are considered as cold and lifeless objects which depend solely on commands from central controllers to perform motions and responses. However, mechanical structures have historically exerted great impacts on various aspects of the society. With the fast development of mechanisms, robotics and materials, those machines that can think is re-examined by researchers, from which the concept of mechanical intelligence (MI) emerges. The characteristics of MI in traditional mechanisms, flexible mechanisms and robotics are reviewed, and the underlying scientific problems are elaborated. The relationship between MI and mechanical control system is discussed. It can be believed that the MI will become the one of the most promising directions in the study of intelligent machines or robots due to its high reliability, fast response and safety in human-machine interaction.

Key words: flexible mechanisms, mechanical feedback, mechanical intelligence, robotics