Mitsuru Nakamura

Apparatus for reducing noise in a closed space having divergence detector

An automatic sound suppression system is automatically disengaged whenever noise in an area and generated counter noise deviate in their reverse phase relationship or if the amplitude of the counter noise deviates from that of the noise. The system can also be automatically disengaged whenever divergence prediction means predicts that sounds of the noise and the counter noise diverge or whenever divergence prediction means predict that sounds of the noise and the counter noise are about to diverge. The system can also operate as a vibration reducing apparatus which is also automatically disengaged whenever divergence prediction means predicts that a vibration and a generated countervibration diverge.

Fully-MMIC 76 GHz radar for ACC

The 76 GHz FSK (frequency shift keying) monopulse radar for the ACC (adaptive cruise control) using MMIC (monolithic microwave integrated circuits) has been developed. The radar transmits 2 frequencies in time-duplex, and measures the distance and the relative speed of targets. The monopulse feature detects the azimuth angle of targets without a scanning mechanism. A fully-MMIC 76 GHz module was developed, and the module was incorporated with microstrip-patch planar antennas. The MMIC module and signal processing electronics were combined into compact one-body unit. Basic radar performance and the new feature of the signal processing algorithm to discriminate multiple stationary targets were evaluated with good results.

Active Vibration Control of Stationary Vibration. Effect of Number and Location of Control Forces.

Recently, active vibration control has been applied to some bridges and buildings. However, the control has only been used to reduce vibration of lower modes. Control methods and spillover problems have also been discussed, but little has been done in terms of analysis of the number and location of actuators. For reduction of the vibration of higher modes, it is necessary to use many actuators. In terms of industrial application, it is important to know the necessary number and optimum location of actuators in order to obtain the required vibration reduction. In this report, we discuss the relationship between the number and location of actuators and vibration reduction for stationary vibration of a simple supported uniform beam. The following results were obtained. First, vibration reduction is strongly affected by the location of the actuators. Second, vibration reduction varies according to the distribution pattern of forces. Based on the findings, an estimation technique for the vibration reduction was proposed.