Cyclic scheduling in small-scale robotic cells served by a multi-function robot

The industrial robot is one of the popular devices used in fully automatic production lines as material handling tool. A consequential problem is finding a cyclic robot movement which gives the maximum cell output in mass production environments. The Robotic Cell Scheduling Problem (RCSP) is predominantly separated into two different problems: Single-Function Robotic Cell (SFRC) and Multi-Function Robotic Cell (MFRC) scheduling problem. These problems are layout-oriented and operation-oriented, respectively. Literature concerning with former case considered a robotic system served by a transporting robot performing a single task. This kind of transporting robot is usually called Single-Function Robot (SFR). For the latter case, the robotic system served by a Multi-Function Robot (MFR) which simultaneously perform an arbitrary task in addition to parts transportation task. Giving a real-life example of MFRs, the use of a class of grippers performing in-process control is significantly increased in industry. The grippers, install at the end of MFR arm, can perform quality control tasks (e.g. accurately measure diameters) while part is carried to next machine. Figure 1 shows an example of these grippers used for measuring the diameter of crankshaft [1]. The measuring heads are integrated into the automation by adding gages and crankshaft locating features to MFR using in these lines. Also, there is a special kind of MFR, namely SDA10, which is suitable for assembly and part transfer in production lines especially if fixturing is costly [2]. Thus, it is crucial to undertake a comprehensive research onto effect of MFRs on production rate