In this paper we investigate the e®ects of microphone and speaker locations on the performance of active noise control in ducts. We study a so-called \symmetric" con ̄guration in which the collocated performance microphone/control speaker and the collocated measurement microphone/disturbance source pairs are located equidistance from the duct center. By applying an \alignment angle" analysis to ...

The development of a novel system for the generation and representation of haptic information in virtual reality is described. With this system the stiffness distribution of mechanically inhomogeneous objects can be detected and made perceivable for users at distant locations. The sensor part is based on ultrasonic elastography and the actuator part utilizes the ability of electrorheological fl...

A constructive method is developed to obtain optimal sensor and actuator locations for inverse optimal state estimation and control of a class of linear distributed parameter systems (DPSs). Given the inverse optimal state estimators and controllers for linear DPSs developed by the first author recently, it is shown that the performance index for optimal locations of sensors and actuators is th...

A novel system for the generation and representation of haptic information in virtual reality is described. With this system the stiffness distribution of mechanically inhomogeneous objects can be detected and made perceivable for users at distant locations. The sensor part is based on ultrasonic elastography and the actuator part utilizes the ability of electrorheological fluids to change thei...

In this research, a functionally graded microbeam bonded with piezoelectric layers is analyzed under electric force. Static and dynamic instability due to the electric actuation is studied because of its importance in micro electro mechanical systems, especially in micro switches. In order to prevent pull-in instability, two piezoelectric layers are used as sensor and actuator. A current amplif...

Researchers at NASA Langley Research Center have extensive experience using active structural acoustic control (ASAC) for aircraft interior noise reduction. One aspect of ASAC involves the selection of optimum locations for microphone sensors and force actuators. This paper explains the importance of sensor/actuator selection, reviews optimization techniques, and summarizes experimental and num...

During dental sinus lift surgery, it is important to monitor the thickness of the remaining maxilla to avoid perforating the sinus membrane. Therefore, a sensor should be integrated into ultrasonic dental tools to prevent undesirable damage. This paper presents a piezoelectric (PZT) sensor installed in an ultrasonic transducer to measure the stiffness of high and low materials. Four design type...

In this paper, the active buckling control of smart functionally graded (FG) plates using piezoelectric sensor/actuator patches is studied. A simply supported FG rectangular plate which is bonded with piezoelectric rectangular patches on the top and/or the bottom surface(s) as actuators/sensors is considered. When a constant electric charge is imposed, the governing differential equations of mo...