A Hierarchical Knowledge Based System for Assembly Tasks in Human-robot Cell Manufacturing

Cell production in which a few human workers operate robots to manufacture products is popular in Japan due to its flexibility. However, it is difficult for human workers to teach the robots to perform the assembly tasks. Therefore, this paper proposes a hierarchical knowledge based system to facilitate teaching robots the assembly tasks. The hierarchical knowledge based system divides the teaching task into 3 levels: 1. the task level – human workers breakdown the complex assembly task with HTA (hierarchical task analysis); 2. the plan level – human workers teach robots to assemble each workpiece with the plan knowledge base; 3. the command level – with the command knowledge base, the assembling plan of each workpiece is translated into robot commands and executed by robots. As the knowledge bases in this system updated and augmented during each teaching task, the human workers’ assembling and teaching skills will be accumulated in the system to ease future teaching tasks.