Real time path planning based on the potential method with 3-D diffusion process for an overhead traveling crane

This paper presents a method to establish real time path planning for three-dimensional (3-D) autonomous mobile overhead crane system for prospective factories. The proposed crane system is constructed from a visual system, a planning system and a control system. In the visual system, CCD image sensors, laser line markers and ultra sonic sensor (USS) are used to scan the environment of transfer space. The original transfer environment is recognized by CCD image sensors and laser line markers while real-time partial changes of transfer environment are recognized by USS. In the planning system, taking advantage of the previous research for the off-line path planning based on the potential method, expanded planning system is proposed to accomplish the on-line path planning. In this system, transfer path is reconstructed as environmental changes occur by means of the potential method. Also, this transfer path is used as crane control references.