A specification language for automated design space exploration of production systems

Integrating simulation in the design process of production systems allows the predicted performance of design alternatives to be compared. However, many iterations of specifying the design, constructing the simulation model, performing simulation experiments, and evaluating the simulation results for each (re)design are required. The process of specifying, modelling, simulating, and evaluating a design can be automated using a framework for automated design space exploration of production systems. This paper presents a formal specification language for the design space of a production system topology. Using the specification of the design space, feasible designs can be generated. The language supports the specification of component types, component instances, and constraints such as how many instances of a type are allowed and how components are allowed to be connected. The specification language is validated through an adaptation of an industrial case study

Review of simulation software for cyber-physical production systems with intelligent distributed production control

Many intelligent distributed production control architectures have been developed for cyber-physical production systems (CPPSs), but the difficulty in predicting performance has hindered acceptance by industry. Performance predictions for systems with conventional control can be made by simulating product flow using discrete-event simulation (DES) software. However, DES is inadequate for capturing the intricacies of intelligent distributed production control architectures. Alternatively, agent-based simulation (ABS) software is more effective for capturing distributed intelligence. A hybrid discrete-event and agent-based simulation tool combines the strengths of both approaches, making it effective for capturing the intertwined physical and cyber layers of a CPPS. In this paper, a review is carried out to determine which off-the-shelf simulation tools are capable of using hybrid discrete-event and agent-based simulation for performance predictions in the conceptual design phase of a CPPS. This review is carried out using the following structured steps. First, the scope and evaluation criteria are identified. Next, a selection of simulation tools is collected. The selected tools are then evaluated and classified. Finally, the most promising simulation tool according to this evaluation – Anylogic – is subjected to a case study to assess if hybrid simulation can be used to predict the performance of a CPPS

Traffic control for automated guided vehicles on a grid layout

Automated guided vehicle (AGV) systems are widely used in a variety of industrial environments. The performance of these systems depends heavily on the control strategies used, among others for traffic control. The traffic control strategy should ensure all movements are executed such that the following hard and soft requirements are met. The hard requirements are: the system should be collision-free and deadlock-free, and starvation of all AGVs in the system should not occur. The soft requirements are: priorities should be followed, and starvation of a single AGV and start-stop behavior should be avoided. In this article, we propose an efficient workflow within the traffic control strategy to achieve this. The workflow is suitable for a grid-based system, where the drivable space is discretized into tiles and AGVs move from tile to tile. Tiles need to be reserved for an AGV before the AGV can move over them. Using the workflow, tiles are reserved for AGVs, such that hard requirements are met, and, where possible, also soft requirements are met