ABSTRACT
As discussed in the previous chapters, deadlocks in automated manufacturing systems (AMS) can be classified into two types. The machines in an AMS are versatile, and jobs of different types can be processed concurrently in the system. In the job production processes, jobs compete for manufacturing resources, including machines, buffers, and material handling devices, leading to one type of deadlock. The material handling systems (MHS) in an AMS may be an automated guide vehicle (AGV) system, or composed of a number of robots and conveyors. In an AGV system, AGVs compete for zones and lanes, leading to the other type of deadlocks. In Chapters 7 to 9, we deal with deadlock resolution problems for these two types of deadlocks separately by using the ROPN model presented in Chapter 5. The deadlock resolution problem for the integrated system with multiple AGVs as MHS is dealt with by using the ROPN model in Chapter 10. It shows that AGVs can be used as material handling devices as well as temporary buffers, in order to ease a deadlock resolution problem. Based on this observation, an effective deadlock control policy is presented in Chapter 10.
