Development of vertical power-assisted crane system to reduce the operators´ burden

A power-assisted crane system is proposed. The purpose of this research is to develop a crane system which reduces the operator\´s burden by power assistive function and facilitates the intuitive operation of a heavy object by direct manual manipulation. First, the structure of this system is described, and an analytical reduced order controller is designed to stabilize the system and to optimize response. Second, The effectiveness of this system is demonstrated by experiments. Finally, "limit cycle problem" is pointed out and the behavior of the system when an object contacts to the ground is discussed. An advantage of the proposed analytical controller is to be able to explain its behavior clearly.