This paper deals with a fault detection for a magnetic suspension system by using Generalized Internal Model Control (GIMC) structure. To design a robust fault detection filter, fault detection design problems are formulated as multiple objective optimization problems by minimizing the effects of disturbances and keeping the fault sensitivity involving an LTI system with disturbance and fault signals. The designed fault detection filters by solving each optimization problems are implemented with the magnetic suspension system to verify its validity. In experimental results, the sensor fault is detected by the designed filter. Moreover, the disturbance affection is more reduced than the detection system using the conventional detection filter.

View full abstract

The optimum tapered Burg (OTB) algorithm is based on minimization of the average variance of the estimated frequency of a sinusoid. The decimation technique has also been used to resolve clearly sinusoids of closely spaced frequencies. This paper newly derives the optimum tapered weight for the Burg algorithm with decimation and shows that the variance of the estimated frequency becomes even smaller than that of the OTB algorithm. The decimation technique with this optimum tapered weight is applied to measure sub-micron thickness of multi layer film and its effectiveness is shown.

View full abstract

In this paper, we consider the problem of stabilizing the state feedback control systems that have quantizers in feedback loop. We study “the binary expansion quantization” where by using the finite bits measurement signals are endorded. Since there is no assumption on the infinite fineness of the quantizer, asymptotic stability cannot be ensured. However we derive a sufficient condition, in terms of the matrix norm and the matrix inequality form, on a quantization bit rate and gains for the ultimate boundedness of the state of the closed loop.

View full abstract

This paper empirically investigates the effect of Desktop Grid Environment on the computational cost of Evolution Strategies (ES). Especially, for task scheduling, List Scheduling with Round-robin order Replication (RR) is adopted to reduce waiting time due to synchronization in ES. Computer simulations are conducted which compare with the loss energy of theoretical maximum value and an actual maximum measurement on Desktop Grid Environment for ES. Results on RR prove that the loss energy of an actual maximum measurement is less than that of theoretical maximum value. Moreover, RR can reduce the synchronous waiting time and improve parallel efficiency in comparison with Work Queue algorithm.

View full abstract