This paper describes a formal modeling and verification of an arm pick-and-place system, in which nondeterministic behaviors of the arm state condition and timer function blocks are applied. We design an appropriate PLC program using a ladder diagram (LD) for the arm pick-and-place operation and apply in it a situation where the arm may drop the product or material being gripped because of an external force. In addition, the timer function blocks are used with formalization of their finite-state logical properties. We use an actual model of the arm to verify that safe operations are established for normal product pick-and-place, as well as when the product has fallen. In addition, we perform arm model verifications for five important temporal properties using the NuSMV model checker. We present two types of experiments to validate the safety of the designed LD program. We also verify that the nondeterminism that appears as a result of the system behaviors can be formalized and used to represent logical assumptions for the properties that need to be verified.

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Implementation of verification procedures is required to eliminate design errors that decrease the safety of an automation system. Design errors may vary from case to case but will certainly jeopardize the safety of manufacturing lines and operators. Therefore, checking the possibility of state transitions in the control systems from safe to unsafe states is essential. Formal verification via model checking procedures has proven to be efficient and is widely used. System finite element models are employed to automatically verify certain correctness properties. In this paper, we introduce a method of model checking technique for logic control design. A checking procedure based on Gröbner bases (GB) model is used to analyze and design a controller that meets the requirements defined by a predetermined safety function. We compare our proposed method with symbolic computation tree logic (CTL) model checking based on binary decision diagrams (BDDs). We implemented this technique to a case study by using a crane system.

This paper presents a method to analyze and design the safe control system using the safety function. The safety function is defined to represent a safety domain in the state space. Using a model of controlled plant and a number of control logic examples with appropriate predetermined safety function, we can evaluate whether the whole system is safe or not. Illustrative example shows that the proposed method is effective for verifying safety and designing safe control system.

Reusability of control codes is one of the basic angles in mechanical robotization, especially for the advancement of high dependable control frameworks. In this paper, we examine a general structure and usage of IEC 61499 standard that can be utilized to speak to conveyed control frameworks and rebuilding the control programs. This paper likewise expects to change the current IEC 61131 based model of computerization framework into the models that pursues IEC 61499 standard. We utilize a bore test system as precedent by mimicking the model utilizing Function Block Development Kit (FBDK) in light of IEC 61499. Accordingly, a piece of the control codes can be used for reusable reason to accomplish framework control objective.