[Show abstract][Hide abstract] ABSTRACT: In the field of civil engineering, wireless sensor networks are conceived to be deployed in structural monitoring systems. In the structural control applications, the requirement of continuous and real-time sensing represents the main challenge for the wireless sensor network due to the problem of data loss. In this paper, the authors attempt to introduce wireless links and a digital controller into a structural control system for a reduced-scale three-story steel frame mounted on a shaking table. The structural control system mainly consists of four accelerometers, a structural controller, and an active mass damper as actuator. The designed wireless sensors are based on the use of recent low-power System-on-Chip wireless CC1110 transceivers, which integrate an 8051 microcontroller core and are able to operate in most of the license-free ISM (Industrial, Scientific and Medical) frequency bands. The active mass damper is driven by a newly designed digital PID (proportional, integral, and derivative) direct-current motor controller, which is based on the high integration power amplifier LMD18200 and the enhanced 8051 core in CC1110.
Structural Control and Health Monitoring 02/2012; · 1.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The authors' research efforts recently led to the development of a customized wireless control unit which receives the real-time feedbacks from the sensors, and elaborates the consequent control signal to drive the actuator(s). The controller is wireless in performing the data transmission task, i.e., it receives the signals from the sensors without the need of installing any analogue cable connection between them, but it is powered by wire. The actuator also needs to be powered by wire. In this framework, the design of a power management unit is of interest only for the wireless sensor stations, and it should be adaptable to different kind of sensor requirements in terms of voltage and power consumption. In the present paper, the power management efficiency is optimized by taking into consideration three different kinds of accelerometers, a load cell, and a non-contact laser displacement sensor. The required voltages are assumed to be provided by a power harvesting solution where the energy is stored into a capacitor.
SMART STRUCTURES AND SYSTEMS 01/2012; 10:299-312. · 1.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this paper, a newly designed wireless sensing network platform for structural monitoring applications is presented, and the results of a validation test performed in the authors' laboratory are reported. The main features offered by the proposed wireless platform are the capability of real-time and multi-channel data transmission, the high compatibility to different types of sensors, a highly efficient power-supply, and low-cost. Instead of adopting the most commonly used commercial wireless modems, the wireless communication is pursued by implementing an optimized and customized solution based on a recent System on Chip wireless transceiver. The Frequency Division Multiplexing method is exploited to ensure the real-time feature of the multi-channel data transmission. A simple and practical point-to-point topology is pursued. The usage of switching regulators which feature low quiescent current, highly efficient power conversion, an adjustable output voltage, and a high output power make this platform suitable for both low-power and non low-power structural monitoring applications involving different types of sensors. In order to validate the prototyped platform, a laboratory test is performed. The measurements of the acceleration response of a simple 3-storey structure mounted on a shaking table are acquired from both a wired DAQ system and the developed wireless platform. The data comparison enables to validate the efficacy of the real-time, multi-channel wireless transmission.