Tham khảo tài liệu 'petri nets applications part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 391 Design and Implementation of Hierarchical and Distributed Control for Robotic Manufacturing Systems using Petri Nets For the example system the hierarchical and distributed control system has been realized using a set of PCs. Each machine controller is implemented on a dedicated PC. The robot controller executes robot motion control through the transmission of command. The station controller is implemented on another PC. Communications among the controllers are performed using serial communication interfaces. The machine controllers control two conveyors or robots so control software on each PC is written using multithreaded programming. The names of global transitions and their conflict relations are loaded into the coordinator in the station controller. The connection structure of a decomposed Petri net model and conflict relations among local transitions are loaded into the Petri net based controller in a machine controller. In the connection structure a transition of a Petri net model is defined using the names of its input places and output places for example t1-1 b1-1 -b1-11 where the transition t1-1 of Robot controller subsystem is connected to the input place and the output place . For the distributed control system shown in Fig. 9 b information inputted to the loader is as follows. Robot controller t1-21 -b1-3 t1-100 b1-3 -b1-4 t1-71 b1-4 -b1-5 t1-101 b1-5 -b1-6 t1-81 b1-6 -b1-7 t1-31 b1-7 t1-41 -b1-13 t1-102 b1-13 -b1-14 t1-91 b1-14 -b1-15 t1-103 b1-15 -b1-16 t1-51 b1-16 MC controller t2-22 -b2-8 t2-200 b2-8 -b2-9 t2-82 b2-9 -b2-10 t2-32 b2-10 -b2-12 t2-42 b2-11 -b2-17 t2-92 b2-17 Conveyor controller t3-13 -b3-1 t3-23 b3-1 -b3-2 t3-73 b3-2 t3-43 -b3-12 t3-53 b3-12 -b3-19 t3-63 b3-19 Using the names of transitions in the subsystems global transitions are defined for example G2 t0-2 t1-21 t2-22 t3-23 indicates that the global transition G2 is composed of the transition of Station controller subsystem the transition of
