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Recently, with increasing demand for precise micro-components productions, the importance of micro machining processes is increasing in many fields, including the automotive, aerospace engineering, medical instruments and computer industries. However, compared with macro machining processes, it is very difficult to observe the machining process due to its low MRR (material removal rate), very small tool size, high speed spindle, and low sensor signals levels, etc. Micro tool dynamometer can be a solution for this; however, its applications are limited due to the expense, sensitivity, robustness, and workpiece size. Thus, in the present study, a useful indirect cutting force measurement method involving an acceleration sensor and current hall sensor is proposed. A series of experiments were performed on a precise micro machining stage. Measured signals were analyzed in the frequency domain after FFT (Fast Fourier Transform), and the results were compared with the cutting force components measured via the acceleration sensor and current hall sensor, respectively. From the results, it could be verified that the proposed indirect cutting force measurement method is a useful way to monitor the micro end-milling processes. Finally, to predict the cutting forces in micromilling processes, the modified polynomial neural network (PNN) and the back-propagation neural network are compared.

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A new scheme for variable structure control design which is based on eigenvalues assignment of sliding mode is developed. In conventional methods, generally, specific type of system matrix like canonical or regular form is required to construct a switching surface. Furthermore, the methods are not explicit. The new method in this paper solved the problems. No special type of system matrix is required and very explicit. It is shown that the switching surface can be constructed and determined uniquely without any dependency on the system form. The proposed method is based on the fact that the dynamics of sliding mode is determined by system zeros. Finally, a numerical example is given to verify the validity of the results studied in this paper.

The simulators for pump operation developed by domestic or overseas research have been developed for dynamic analysis or operator training purposes. However, previous developed simulators focused on the operators so they are unsuitable for logic designers or commissioning engineers who need to change the operation conditions or logics arbitrarily. In addition, the simulator for two or more condensate pumps' operation, which can be used easily by plant designers or operators, has not been developed. Accordingly, this paper suggests a simulation method that can be used easily for plant designers or operators using MATLAB Simulink. This suggestion helps users who can use MATLAB to implement ANSI/ISA S5.2, which is applied mainly for DCS (Distributed Control System). In addition, to implement the logics specified in the CODE, Sub-Systems were created for the block and evaluated to determine if they can be used in the simulator. In the working level stage using the suggested method, all error possibilities that might occur during the three pumps' rotation operation could be verified with the suggested simulator during the design stage or before operation.